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Sample records for atpap15 enhances phosphorus

  1. Polyphosphate Kinase from Activated Sludge Performing Enhanced Biological Phosphorus Removal†

    OpenAIRE

    Katherine D McMahon; Dojka, Michael A.; Pace, Norman R.; Jenkins, David; Keasling, Jay D.

    2002-01-01

    A novel polyphosphate kinase (PPK) was retrieved from an uncultivated organism in activated sludge carrying out enhanced biological phosphorus removal (EBPR). Acetate-fed laboratory-scale sequencing batch reactors were used to maintain sludge with a high phosphorus content (approximately 11% of the biomass). PCR-based clone libraries of small subunit rRNA genes and fluorescent in situ hybridization (FISH) were used to verify that the sludge was enriched in Rhodocyclus-like β-Proteobacteria kn...

  2. Enhanced Biological Phosphorus Removal for Liquid Dairy Manure

    OpenAIRE

    Hong, Yanjuan

    2009-01-01

    Enhanced biological phosphorus removal (EBPR) has been widely used in municipal wastewater treatment, but no previous studies have examined the application of EBPR to treat dairy manure. This study was conducted to evaluate the (i) performance of pilot-scale EBPR systems treating liquid dairy manure, to balance the ratio of nitrogen to phosphorus in manure to meet crop nutrient requirements, (ii) effects of dissolved oxygen and solids retention time on the efficiency of EBPR, and (iii) effect...

  3. Enhanced biological phosphorus removal employing EDTA disodium

    Energy Technology Data Exchange (ETDEWEB)

    Bojinova, D.; Velkova, R. [Higher Inst. of Chemical Technology, Sofia (Bulgaria)

    1996-12-31

    The biological phosphorus removal is a promising alternative to the conventional chemical technologies for processing of phosphate raw materials. The object of this study was the effect of EDTA disodium on the biotreatment of tunisian phosphorite with the strain of Aspergillus niger. The incubation was carried out in two nutritive mediums, with different phosphate content. The experimental results showed that the additives of EDTA disodium in the nutritive medium increased the rate of extraction of P{sub 2}O{sub 5} and shortened significantly the time for biological leaching. 5 refs., 3 figs., 2 tabs.

  4. Calcium effect on the metabolic pathway of phosphorus accumulating organisms in enhanced biological phosphorus removal systems.

    Science.gov (United States)

    Zhang, Hai-Ling; Sheng, Guo-Ping; Fang, Wei; Wang, Yong-Peng; Fang, Cai-Yun; Shao, Li-Min; Yu, Han-Qing

    2015-11-01

    Phosphorus accumulating organisms (PAOs) have been found to act as glycogen-accumulating organisms (GAOs) under certain conditions, thus, the deterioration in the performance of enhanced biological phosphorus removal systems is not always attributed to the proliferation of GAOs. In this work, the effects of calcium on the metabolic pathway of PAOs were explored. It was found that when the influent Ca(2+) concentration was elevated, the tendency and extent of extracellular calcium phosphate precipitation increased, and the intracellular inert Ca-bound polyphosphate was synthesized, while the microbial population remained almost unchanged. The changes in the ratios of phosphorus released/acetate uptaken, the glycogen degraded/acetate uptaken and the poly-β-hydroxyalkanoates synthesized/acetate uptaken during the anaerobic period confirm that, as the influent Ca(2+) concentration was increased, the polyphosphate-accumulating metabolism was partially shifted to the glycogen-accumulating metabolism. At an influent Ca(2+) around 50 mg/L, in addition to the extracellular calcium phosphate precipitation, the intracellular inert Ca-bound polyphosphate synthesis might also be involved in the metabolic change of PAOs. The results of the present work would be beneficial to better understand the biochemical metabolism of PAOs in enhanced biological phosphorus removal systems. PMID:26233656

  5. A novel approach for phosphorus recovery and no wasted sludge in enhanced biological phosphorus removal process with external COD addition.

    Science.gov (United States)

    Xia, Cheng-Wang; Ma, Yun-Jie; Zhang, Fang; Lu, Yong-Ze; Zeng, Raymond J

    2014-01-01

    In enhanced biological phosphorus removal (EBPR) process, phosphorus (P) in wastewater is removed via wasted sludge without actual recovery. A novel approach to realize phosphorus recovery with special external chemical oxygen demand (COD) addition in EBPR process was proposed. During the new operating approach period, it was found that (1) no phosphorus was detected in the effluent; (2) with an external addition of 10 % of influent COD amount, 79 % phosphorus in the wastewater influent was recovered; (3) without wasted sludge, the MLVSS concentration in the system increased from 2,010 to 3,400 mg/L and kept stable after day 11 during 24-day operating period. This demonstrates that the novel approach is feasible to realize phosphorus recovery with no wasted sludge discharge in EBPR process. Furthermore, this approach decouples P removal and sludge age, which may enhance the application of membrane bioreactor for P removal. PMID:24122666

  6. Enhanced Biological Phosphorus Removal from Dairy Manure to Meet Nitrogen:Phosphorus Crop Nutrient Requirements

    OpenAIRE

    Yanosek, Kristina Anne

    2002-01-01

    Over the last two decades, livestock operations have become highly concentrated due to growing trends towards larger, more confined facilities and a decrease in cropland on smaller farms. This has led to greater amounts of excess manure nutrients on farms, increasing the potential for nutrient pollution of water bodies from runoff. The purpose of this study was to determine if enhanced biological phosphorus removal (EBPR) is a viable alternative for managing excess manure nutrients on dairy...

  7. Phosphorus removal and recovery from domestic wastewater in a novel process of enhanced biological phosphorus removal coupled with crystallization.

    Science.gov (United States)

    Zou, Haiming; Wang, Yan

    2016-07-01

    A new process of enhanced biological phosphorus removal coupled with crystallization recovery of phosphorus was developed here, where the feasibility of nutrients removal and potential for phosphorus recovery from domestic wastewater was further assessed. Results showed that an excellent nutrients removal and phosphorus recovery performance was achieved, in which the averaged COD, PO4(3-)-P and NO3(-)-N removal efficiencies were 82.6%, 87.5% and 91.6%, respectively and a total of 59.3% of phosphorus was recovered as hydroxyapatite. What's more, crystallization recovery of phosphorus greatly enhanced the biological phosphorus removal efficiency. After the incorporation of the phosphorus recovery column via side-stream, the phosphorus concentration of effluent was significantly decreased ranging from 1.24mg/L to 0.85mg/L, 0.52mg/L and 0.41mg/L at the lateral flow ratios of 0, 0.1, 0.2 and 0.3, respectively. The results obtained here would be beneficial to provide a prospective alternative for phosphorus removal and recovery from wastewater. PMID:27003794

  8. Phosphorus

    OpenAIRE

    Linderholm, Kersti

    2012-01-01

    Phosphorus is an essential element for plants, animals and humans and is also a scarce resource as a raw material for fertilizer production. The flows of phosphorus to and from Swedish agriculture and food chain was investigated with a material flow analysis (MFA). The fertilizer value of recycled phosphorus in chemically precipitated sewage sludge, biological sludge, mineral fertilizer and ash was investigated in a three-year field experiment. The impact of different phosphorus fertilizers o...

  9. Enhanced biological phosphorus removal with different carbon sources.

    Science.gov (United States)

    Shen, Nan; Zhou, Yan

    2016-06-01

    Enhanced biological phosphorus removal (EBPR) process is one of the most economical and sustainable methods for phosphorus removal from wastewater. However, the performance of EBPR can be affected by available carbon sources types in the wastewater that may induce different functional microbial communities in the process. Glycogen accumulating organisms (GAOs) and polyphosphate accumulating organisms (PAOs) are commonly found by coexisting in the EBPR process. Predominance of GAO population may lead to EBPR failure due to the competition on carbon source with PAO without contributing phosphorus removal. Carbon sources indeed play an important role in alteration of PAOs and GAOs in EBPR processes. Various types of carbon sources have been investigated for EBPR performance. Certain carbon sources tend to enrich specific groups of GAOs and/or PAOs. This review summarizes the types of carbon sources applied in EBPR systems and highlights the roles of these carbon sources in PAO and GAO competition. Both single (e.g., acetate, propionate, glucose, ethanol, and amino acid) and complex carbon sources (e.g., yeast extract, peptone, and mixed carbon sources) are discussed in this review. Meanwhile, the environmental friendly and economical carbon sources that are derived from waste materials, such as crude glycerol and wasted sludge, are also discussed and compared. PMID:27087523

  10. Species and distribution of inorganic and organic phosphorus in enhanced phosphorus removal aerobic granular sludge.

    Science.gov (United States)

    Huang, Wenli; Huang, Weiwei; Li, Huifang; Lei, Zhongfang; Zhang, Zhenya; Tay, Joo Hwa; Lee, Duu-Jong

    2015-10-01

    The species and distribution of phosphorus (P) in an enhanced biological phosphorus removal (EBPR)-aerobic granular sludge (AGS) were fractionated and further analyzed. Results showed that microbial cells, extracellular polymeric substances (EPS) and mineral precipitates contributed about 73.7%, 17.6% and 5.3-6.4% to the total P (TP) of EBPR-AGS, respectively. Inorganic P (IP) species were orthophosphate, pyrophosphate and polyphosphate among which polyphosphate was the major P species in the AGS, cells and EPS. Monoester and diester phosphates were identified as the organic P (OP) species in the AGS and cells. Hydroxyapatite (Ca5(PO4)3OH) and calcium phosphate (Ca2(PO4)3) were the dominant P minerals accumulated in the core of the granules. Cells along with polyphosphate were mainly in the outer layer of AGS while EPS were distributed in the whole granules. Based on the above results, the distribution of IP and OP species in AGS has been conceived. PMID:26144019

  11. Results of activated sludge plants applying enhanced biological phosphorus removal

    Energy Technology Data Exchange (ETDEWEB)

    Machado, A.; Pinto, M.; Neder, K.; Hoffmann, H.

    1989-02-01

    To stop the eutrophication in lakes and rivers, the input of nutrient and phosphorus compounds must be limited. The biological elimination of phosphorus describes a possibility, to reduce phosphorus in the biological stage of a treatment plant to a considerable extent. In this paper the process-system and the operation-results of a pilot plant and two municipal treatment plants are presented, where biological phosphorus reduction about 80% takes place without any constructional modifications.

  12. “Candidatus Propionivibrio aalborgensis”: A Novel Glycogen Accumulating Organism Abundant in Full-Scale Enhanced Biological Phosphorus Removal Plants

    DEFF Research Database (Denmark)

    Albertsen, Mads; McIlroy, Simon Jon; Stokholm-Bjerregaard, Mikkel;

    2016-01-01

    Enhanced biological phosphorus removal (EBPR) is widely used to remove phosphorus from wastewater. The process relies on polyphosphate accumulating organisms (PAOs) that are able to take up phosphorus in excess of what is needed for growth, whereby phosphorus can be removed from the wastewater...

  13. Integrative microbial community analysis reveals full-scale enhanced biological phosphorus removal under tropical conditions

    OpenAIRE

    Yingyu Law; Rasmus Hansen Kirkegaard; Angel Anisa Cokro; Xianghui Liu; Krithika Arumugam; Chao Xie; Mikkel Stokholm-Bjerregaard; Drautz-Moses, Daniela I.; Per Halkjær Nielsen; Stefan Wuertz; Rohan B. H. Williams

    2016-01-01

    Management of phosphorus discharge from human waste is essential for the control of eutrophication in surface waters. Enhanced biological phosphorus removal (EBPR) is a sustainable, efficient way of removing phosphorus from waste water without employing chemical precipitation, but is assumed unachievable in tropical temperatures due to conditions that favour glycogen accumulating organisms (GAOs) over polyphosphate accumulating organisms (PAOs). Here, we show these assumptions are unfounded b...

  14. Diversity enhances agricultural productivity via rhizosphere phosphorus facilitation on phosphorus-deficient soils.

    Science.gov (United States)

    Li, Long; Li, Shu-Min; Sun, Jian-Hao; Zhou, Li-Li; Bao, Xing-Guo; Zhang, Hong-Gang; Zhang, Fu-Suo

    2007-07-01

    Intercropping, which grows at least two crop species on the same pieces of land at the same time, can increase grain yields greatly. Legume-grass intercrops are known to overyield because of legume nitrogen fixation. However, many agricultural soils are deficient in phosphorus. Here we show that a new mechanism of overyielding, in which phosphorus mobilized by one crop species increases the growth of a second crop species grown in alternate rows, led to large yield increases on phosphorus-deficient soils. In 4 years of field experiments, maize (Zea mays L.) overyielded by 43% and faba bean (Vicia faba L.) overyielded by 26% when intercropped on a low-phosphorus but high-nitrogen soil. We found that overyielding of maize was attributable to below-ground interactions between faba bean and maize in another field experiment. Intercropping with faba bean improved maize grain yield significantly and above-ground biomass marginally significantly, compared with maize grown with wheat, at lower rates of P fertilizer application (112.5 kg of P(2)O(5) per hectare). By using permeable and impermeable root barriers, we found that maize overyielding resulted from its uptake of phosphorus mobilized by the acidification of the rhizosphere via faba bean root release of organic acids and protons. Faba bean overyielded because its growth season and rooting depth differed from maize. The large increase in yields from intercropping on low-phosphorus soils is likely to be especially important on heavily weathered soils.

  15. Enhanced biological phosphorus removal - results of experiences in three large waste water treatment plants

    International Nuclear Information System (INIS)

    Within a scientific project especially the operation of four real-size sewage treatment plants with different processes of enhanced biological phosphorus removal is investigated under the aspect of efficiency, stability, practicability and costs of the enhanced biological phosphorus removal. Three plants and first results are explained and compared as well with one another as with data, which are generally regarded as favourable conditions for the enhanced biological phosphorus removal. Between the plants there are significant differences in the degree of P-elimination mainly due to different characteristics of the wastewater. An important influence on P-effluent concentrations may be exacted by P-resolution in the final clarifier. (orig.)

  16. Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.

    Science.gov (United States)

    Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2014-02-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4(2-)/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production and oxygen demand. Recently, the SANI(®) process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30 °C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0 mg P/mg S. There were no conventional PAOs in the sludge. PMID:24342048

  17. Some hints concerning phosphorus release and phosphorus uptake properties in enhanced biological phophorus removal; Empfehlungen zur Durchfuehrung und Auswertung von Phosphatrueckloese- und -aufnahmeversuchen

    Energy Technology Data Exchange (ETDEWEB)

    Scheer, H. [Hannover Univ. (Germany). Inst. fuer Siedlungswasserwirtschaft und Abfalltechnik

    1996-01-01

    Reproducible methods of analysis are necessary for the estimation of phosphorus release and phosphorus uptake properties of activated sludges in wastewater treatment plants using enhanced biological phosphorus removal (EBPR). These methods have to allow for comparisons and evaluations of different activated sludges impressed by EBPR. A phosphorus release and phosphorus uptake attempt modified for different operation facilities and conditions in wastewater treatment plants was developed. Using these methods phosphorus release and phosphorus uptake properties of activated sludges can be described qualitativley and quantitatively. (orig.) [Deutsch] Zur Abschaetzung der Phosphatrueckloese- und -aufnahmeeigenschaften eines belebten Schlammes bei Klaeranlagen mit vermehrter biologischer Phosphorelimination (BIO-P) bedarf es reproduzierbarer Untersuchungsmethoden, die einen Vergleich und eine Beurteilung hierzu durchgefuehrter Untersuchungen ermoeglichen. Hierzu wurde ein fuer klaeranlagenspezifische Betriebsbedingungen modifizierter Phosphatrueckloese- und -aufnahmeversuche entwickelt, mit dem die Phosphatrueckloese- und -aufnahmeeigenschaften eines belebten Schlammes qualitativ und quantitativ beschrieben werden koennen. (orig.)

  18. Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges.

    Science.gov (United States)

    Zeng, Wei; Li, Boxiao; Yang, Yingying; Wang, Xiangdong; Li, Lei; Peng, Yongzhen

    2014-02-01

    Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5% of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10(-3) mg HNO₂-N/L, aerobic P-uptake and oxidation of intercellular poly-β-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10(-3) mg HNO2-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10(-3) and 2.13 × 10(-3) mg HNO₂-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite. PMID:23771179

  19. Enhanced biological phosphorus removal in the wastewater treatment plant of Bunnik

    Energy Technology Data Exchange (ETDEWEB)

    Vries, H.P. de; Rensink, J.H.

    1989-02-01

    At several sewage treatment plants in the Netherlands there has been continuously found a remarkable high phosphorus removal rate, without using chemical additions. In Bunnik this is up to 90%. In the effluent we will mostly find less than 1 mg P/l. At the Bunnik plant we deal with biological excess phosphorus removal. Biological phosphorus removal is based on the luxury uptake of phosphorus by some bacteria. On certain circumstances micro-organisms of the genius Acinetobacter stored excess amounts of phosphates in their cells. In 1984 a project started, financed by the institute for inland waters and wastewater treatment (DBW/RIZA). The purpose of this research project was to find factors which were, responsible for the remarkable enhanced phosphorus removal in the Bunnik plant.

  20. Enhanced Biological Phosphorus Removal with Pseudomonas putida GM6 from Activated Sludge

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The enhanced biological phosphorus removal (EBPR) method is widely adopted for phosphorus removal from wastewater, yet little is known about its microbiological and molecular mechanisms. Therefore, it is difficult to predict and control the deterioration of the EBPR process in a large-scale municipal sewage treatment plant. This study used a novel strain isolated in the laboratory, Pseudomonas putida GM6, which had a high phosphate accumulating ability and could recover rapidly from the deteriorated system and enhance the capability of phosphorus removal in activated sludge. Strain GM6 marked with gfp gene, which was called GMTR, was delivered into a bench-scale sequencing batch reactor (SBR)of low efficiency, to investigate the colonization of GMTR and removal of phosphorus. After 21 days, the proportion of GMTR in the total bacteria of the sludge reached 9.2%, whereas the phosphorus removal rate was 96%, with an effluent concentration of about 0.2 mg L-1. In the reactor with the addition of GMTR, phosphorus was removed quickly, in 1 h under anaerobic conditions, and in 2 h under aerobic conditions. These evidences were characteristic of EBPR processes.Field testing was conducted at a hospital sewage treatment facility with low phosphorus removal capability. Twentyone days after Pseudononas putida GM6 was added, effluent phosphorus concentration remained around 0.3 mg L-1,corresponding to a removal rate of 96.8%. It was therefore demonstrated that Pseudomonas putida GM6 could be used for a quick startup and enhancement of wastewater biological phosphorus removal, which provided a scientific basis for potential large-scale engineering application.

  1. A phosphorus-free anolyte to enhance coulombic efficiency of microbial fuel cells

    Science.gov (United States)

    Tang, Xinhua; Li, Haoran; Du, Zhuwei; Ng, How Yong

    2014-12-01

    In this study, a phosphorus-free anolyte is prepared by using bicarbonate to replace phosphate buffer for application in two chamber microbial fuel cells (MFCs). Optical density test and Bradford protein assay shows that this phosphorus-free anolyte effectively inhibits the growth and reproduction of microorganisms suspended in the solution and greatly reduces the suspended cell mass. As a result, it considerably enhances the coulombic efficiency (CE) of MFCs. When the acetate concentration is 11 mM, the CE of the MFC using the pH 7 phosphate-containing anolyte is 9.7% and the CE with the pH 8.3 phosphate-containing anolyte is 9.1%, while the CE of the MFC using the phosphorus-free anolyte (pH 8.3) achieves 26.6%. This study demonstrates that this phosphorus-free anolyte holds the potential to enhance the feasibility for practical applications of MFCs.

  2. A metagenome of a full-scale microbial community carrying out enhanced biological phosphorus removal

    OpenAIRE

    Albertsen, Mads; Hansen, Lea Benedicte Skov; Saunders, Aaron Marc; Nielsen, Per Halkjær; Nielsen, Kåre Lehmann

    2011-01-01

    Enhanced biological phosphorus removal (EBPR) is widely used for removal of phosphorus from wastewater. In this study, a metagenome (18.2 Gb) was generated using Illumina sequencing from a full-scale EBPR plant to study the community structure and genetic potential. Quantitative fluorescence in situ hybridization (qFISH) was applied as an independent method to evaluate the community structure. The results were in qualitative agreement, but a DNA extraction bias against gram positive bacteria ...

  3. A Comparative Study of the Bacterial Community in Denitrifying and Traditional Enhanced Biological Phosphorus Removal Processes

    OpenAIRE

    Lv, Xiao-Mei; Shao, Ming-Fei; Li, Chao-Lin; Li, Ji; Gao, Xin-lei; Sun, Fei-Yun

    2014-01-01

    Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphoru...

  4. Determination of operational parameters of anaerobic phase for enhanced phosphorus removal in MBR

    Institute of Scientific and Technical Information of China (English)

    HE Sheng-bing; WANG Bao-zhen; WANG Lin; JIANG Yi-feng

    2004-01-01

    Two runs of experiments were carried out to obtain an understanding of phosphorus release and uptake under the anaerobic condition and then the aerobic condition respectively. Under anaerobic condition, it was found that the extent of phosphorus release appeared to increase with the increase of the initial organic loading rate when the initial organic loading rate was up to 0.1 gSCOD/gMLSS.When the initial organic loading rate was higher than 0.1 gSCOD/gMLSS, the amount of phosphorus release per unit mass of MLSS reached nearly a same stationary value, and it seemed this is not affected by organic loading rate when there is external available substrate remained. In addition, the effect of NOx-N on the phosphorus release and uptake was also investigated, it was proved that the denitrifiers has an advantage over polyphosphate accumulating bacteria in competition for organic substrate under anoxic condition. Therefore, the existence of NOx-N is disadvantageous to the phosphorus release. Based upon the above investigations, the process configuration of membrane bioreactor(MBR) in combination with anaerobic phase was proposed to enhance the removal of phosphorus in treating domestic wastewater. During the experimental period of four months, average removals of 92.50%, 84.25%, 100%, 94.09% and 85.33% were achieved for COD, TP, SS, NH3-N and TN respectively.

  5. Kinetic analysis of enhanced biological phosphorus removal in a hybrid integrated fixed film activated sludge process

    International Nuclear Information System (INIS)

    Hybrid integrated fixed film activated sludge is a promising process for the enhancement of nitrification, denitrification and phosphorus removal in conventional activated sludge systems that can be used for upgrading biological nutrient removal, particularly when they have space limitations or need modifications that will require large monetary expenses. In this research, successful implementation of hybrid integrated fixed film activated sludge process at temperate zone wastewater treatment facilities has been studied by the placement of fixed film media into aerobic, anaerobic and anoxic zones. The primary objective of this study was to investigate the incorporation of enhanced biological phosphorus removal into hybrid integrated fixed film activated sludge systems and study the interactions between the fixed biomass and the mixed liquor suspended solids with respect to substrate competition and nutrient removal efficiencies. A pilot-scale anaerobic-anoxic-oxic configuration system was used. The system was operated at different mean cell residence times and influent chemical oxygen demand/total phosphorus ratios and with split influent flows. The experimental results confirmed that enhanced biological phosphorus removal could be incorporated successfully into hybrid integrated fixed film activated sludge system, but the redistribution of biomass resulting from the integration of fixed film media and the competition of organic substrate between enhanced biological phosphorus removal and denitrification would affect performances. Also, kinetic analysis of the reactor with regarding to phosphorus removal has been studied with different kinetic models and consequently the modified Stover-Kincannon kinetic model has been chosen for modeling studies and experimental data analysis of the hybrid integrated fixed film activated sludge reactor

  6. Fouling of enhanced biological phosphorus removal-membrane bioreactors by humic-like substances.

    Science.gov (United States)

    Poorasgari, Eskandar; König, Katja; Fojan, Peter; Keiding, Kristian; Christensen, Morten Lykkegaard

    2014-12-01

    Fouling by free extracellular polymeric substances was studied in an enhanced biological phosphorus removal-membrane bioreactor. It was demonstrated that the free extracellular polymeric substances, primarily consisting of humic-like substances, were adsorbed to the membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant. Infrared analyses indicated the presence of the humic-like substances on the membrane's active surface after filtration of the free extracellular polymeric substances suspension. Scanning electron microscopy showed the presence of a gel layer on the membrane surface after filtration of the free extracellular polymeric substances suspension. The gel layer caused a significant decline in water flux. This layer was not entirely removed by a backwashing, and the membrane's water flux could not be re-established. The membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant showed infrared spectra similar to that fouled by the free extracellular polymeric substances suspension in the laboratory. Thus, the results of this study show the importance of humic-like substances in irreversible fouling of enhanced biological phosphorus removal-membrane bioreactor systems. PMID:25014564

  7. Recent developments in the biochemistry and ecology of enhanced biological phosphorus removal

    NARCIS (Netherlands)

    Kortstee, GJJ; Appeldoorn, KJ; Bonting, CFC; van Niel, EWJ; van Veen, HW

    2000-01-01

    Most of the genes encoding the enzymes involved in polyP synthesis and degradation and in phosphate transport have been studied in various Gram-negative bacteria. Progress has also been made in studying the biochemical mechanisms underlying the process of enhanced biological phosphorus removal (EBPR

  8. [Review on the main microorganisms and their metabolic mechanisms in enhanced biological phosphorus removal (EBPR) systems].

    Science.gov (United States)

    Sun, Xue; Zhu, Wei-Jing; Wang, Liang; Wu, Wei-Xiang

    2014-03-01

    Enhanced biological phosphorus removal (EBPR) process is applied widely for removing phosphorus from wastewater. Studies on functional microorganisms and their metabolic mechanisms are fundamental to effective regulation for stable operation and performance improvement of EBPR process. Two main types of microorganisms in EBPR systems, polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) were selected to summarize their metabolic mechanisms such as substrate uptake mechanisms, glycogen degradation pathways, extent of TCA cycle involvement and metabolic similarity between PAOs and GAOs. Application of molecular biology techniques in microbiology and metabolic mechanisms involved in the EBPR system was evaluated. Potential future research areas for the EBPR system and process optimization were also proposed. PMID:24984512

  9. Enhanced biological phosphorus removal from activated sludge system; Eliminacion biologica del fosfor en aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Pidre Bocardo, J. R.; Toja Santillana, J.; Alonso Alvarez, E. [Sevilla (Spain)

    1999-06-01

    A literature review of enhanced biological phosphorus removal was performed. This biological removal is based on the selective enrichment of bacteria accumulating inorganic polyphosphate, obtained at a cyclic regime of alternating anaerobic and aerobic conditions; or anaerobic, anoxic and aerobic zones for combined nitrogen and phosphorus removal. Some bacterial groups may to be implicate in this process, the gen Acinetobacter has been the most studied. In this paper a study of phosphorate forms from wastewater for a conventional activated sludge system is presented. (Author) 40 refs.

  10. A metagenome of a full-scale microbial community carrying out Enhanced Biological Phosphorus Removal

    DEFF Research Database (Denmark)

    Albertsen, Mads; Hansen, Lea Benedicte Skov; Saunders, Aaron Marc;

    2012-01-01

    Enhanced biological phosphorus removal (EBPR) is widely used for removal of phosphorus from wastewater. In this study, a metagenome (18.2 Gb) was generated using Illumina sequencing from a full-scale EBPR plant to study the community structure and genetic potential. Quantitative fluorescence...... the use of qFISH. The genetic potential for community function showed enrichment of genes involved in phosphate metabolism and biofilm formation, reflecting the selective pressure of the EBPR process. Most contigs in the assembled metagenome had low similarity to genes from currently sequenced genomes......, underlining the need for more reference genomes of key EBPR species. Only the genome of ‘Candidatus Accumulibacter’, a genus of phosphorus-removing organisms, was closely enough related to the species present in the metagenome to allow for detailed investigations. Accumulibacter accounted for only 4.8% of all...

  11. Enhanced visible light photocatalytic property of red phosphorus via surface roughening

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weibing, E-mail: lwbing@qust.edu.cn [School of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042 (China); Yue, Jiguang; Hua, Fangxia; Feng, Chang [School of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042 (China); Bu, Yuyu; Chen, Zhuoyuan [Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071 (China)

    2015-10-15

    Highlights: • Photocatalytic RhB degradation of red phosphorus was studied for the first time. • Surface rough can increase the photocatalysis reaction active sites. • Surface rough red phosphorus possesses high photocatalytic performance. • Surface rough red phosphorus has high industrial application value. - Abstract: Red phosphorus with rough surface (SRP) was prepared by catalyst-assisted hydrothermal synthesis using Co{sup 2+} catalyst. The photocatalytic Rhodamine B (RhB) degradation of red phosphorus (RP) and SRP was studied for the first time in this work. Rough surface can enhance the dye adsorption ability of RP. About 75% RhB was absorbed by SRP after 30-min adsorption in 100 ml RhB solution with concentration of 10 mg l{sup −1} in dark. After only 10 min of illumination by visible light, more than 95% RhB was degraded, indicating that SRP has a great application potential in the area of photocatalysis. The photocatalytic RhB degradation properties of RP are much weaker than those of SRP. The increase of the number of the active sites for the photocatalytic reactions, the electron mobility and the lifetime of the photogenerated electrons cause the significant improvement of the photocatalytic performance of SRP based on the experimental results obtained.

  12. Enhancement of Phosphorus Solubility by Humic Substances in Ferrosols

    Institute of Scientific and Technical Information of China (English)

    HUA Quan-Xian; LI Jian-Yun; ZHOU Jian-Min; WANG Huo-Yan; DU Chang-Wen; CHEN Xiao-Qin

    2008-01-01

    An investigation was conducted to study the effect of humic substance (HS) on the phosphorus (P) solubility in acidic soil. The soil (2.5 g), HS (0, 0.5, and 2.5 g), and P as monocalcium phosphate (0.31 and 1.25 g P kg-1 soil) were mixed with 50 mL distilled water and two different sequences of adding HS and P were used. The results indicated that the P concentration in water and 0.01 mol L-1 CaCl2 solution increased with increasing amounts of humic substance. The concentrations of Fe and Al were also increased. However, Olsen P decreased with increasing amount of humic substance.Water-soluble P concentrations from P rates at 0.31 and 1.25 g P kg-1 soil in the treatment with 0.5 g (2.5 g) humic substance addition were 360% and 70% (500% and 90%) higher, respectively, than those in the treatment with no humic substance addition. P extracted by 0.01 mol L-1 CaCl2 in the treatments with 0.5 and 2.5 g humic substance addition was increased by 400% and 540%, respectively, compared with that in the treatment without humic substance at the rate of 0.31 g P kg-1 soil, while the corresponding P concentrations were increased by 80% and 90% at the rate of 1.25 g P kg-1 soil. The order of mixing humic substance and phosphate did not significantly affect desorbed P and labile P extracted with CaCl2.

  13. Pectin enhances rice (Oryza sativa) root phosphorus remobilization.

    Science.gov (United States)

    Zhu, Xiao Fang; Wang, Zhi Wei; Wan, Jiang Xue; Sun, Ying; Wu, Yun Rong; Li, Gui Xin; Shen, Ren Fang; Zheng, Shao Jian

    2015-02-01

    Plants growing in phosphorus (P)-deficient conditions can either increase their exploration of the environment (hence increasing P uptake) or can solubilize and reutilize P from established tissue sources. However, it is currently unclear if P stored in root cell wall can be reutilized. The present study shows that culture of the rice cultivars 'Nipponbare' (Nip) and 'Kasalath' (Kas) in P-deficient conditions results in progressive reductions in root soluble inorganic phosphate (Pi). However, Nip consistently maintains a higher level of soluble Pi and lower relative cell wall P content than does Kas, indicating that more cell wall P is released in Nip than in Kas. P-deficient Nip has a greater pectin and hemicellulose 1 (HC1) content than does P-deficient Kas, consistent with the significant positive relationship between pectin and root-soluble Pi levels amongst multiple rice cultivars. These observations suggest that increased soluble Pi might result from increased pectin content during P starvation. In vitro experiments showed that pectin releases Pi from insoluble FePO4. Furthermore, an Arabidopsis thaliana mutant with reduced pectin levels (qua1-2), has less root soluble Pi and is more sensitive to P deficiency than the wild type (WT) Col-0, whereas NaCl-treated WT plants exhibit both an increased root pectin content and an elevated soluble Pi content during P-starvation. These observations indicate that pectin can facilitate the remobilization of P deposited in the cell wall. This is a previously unknown mechanism for the reutilization of P in P-starved plants.

  14. Enhancing combined biological nitrogen and phosphorus removal from wastewater by applying mechanically disintegrated excess sludge.

    Science.gov (United States)

    Zubrowska-Sudol, Monika; Walczak, Justyna

    2015-06-01

    The goal of the study was to evaluate the possibility of applying disintegrated excess sludge as a source of organic carbon to enhance biological nitrogen and phosphorus removal. The experiment, performed in a sequencing batch reactor, consisted of two two-month series, without and with applying mechanically disintegrated excess sludge, respectively. The effects on carbon, nitrogen and phosphorus removal were observed. It was shown that the method allows enhancement of combined nitrogen and phosphorus removal. After using disintegrated sludge, denitrification effectiveness increased from 49.2 ± 6.8% to 76.2 ± 2.3%, which resulted in a decline in the NOx-N concentration in the effluent from the SBR by an average of 21.4 mg NOx-N/L. Effectiveness of biological phosphorus removal increased from 28.1 ± 11.3% to 96.2 ± 2.5%, thus resulting in a drop in the [Formula: see text] concentration in the effluent by, on average, 6.05 mg PO4(3-)-P/L. The application of disintegrated sludge did not deteriorate effluent quality in terms of COD and NH4(+)-N. The concentration of NH4(+)-N in both series averaged 0.16 ± 0.11 mg NH4(+)-N/L, and the concentration of COD was 15.36 ± 3.54 mg O2/L. PMID:25776916

  15. Enhanced phosphorus flux from overlying water to sediment in a bioelectrochemical system.

    Science.gov (United States)

    Yang, Qinzheng; Zhao, Huazhang; Zhao, Nannan; Ni, Jinren; Gu, Xuejing

    2016-09-01

    This report proposed a novel technique for the regulation of phosphorus flux based on a bioelectrochemical system. In the simulated water system, a simple in situ sediment microbial fuel cell (SMFC) was constructed. SMFC voltage was increased with time until it was 0.23V. The redox potential of the sediment was increased from -220mV to -178mV during the process. Phosphorus concentration in the water system was decreased from 0.1mg/L to 0.01mg/L, compared with 0.09mg/L in the control. The installation of a SMFC produced an external current and internal circuit, which promoted the transfer of phosphate in overlying water to the sediment, enhanced the microbial oxidation of Fe(2+), and increased the formation of stable phosphorus in sediment. In conclusion, phosphorus flux from the overlying water to sediment was enhanced by SMFC, which has the potential to be used for eutrophication control of water bodies. PMID:27240233

  16. Enhanced biological phosphorus removal - results of experiences in three large waste water treatment plants. Biologische Phosphatelimination - Betriebserfahrungen an drei Grossanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, P. (Fachbereich Bauingenieurwesen, FG Siedlungswasserwirtschaft, Kassel Univ. (Gesamthochschule) (Germany)); Telgmann, U. (Fachbereich Bauingenieurwesen, FG Siedlungswasserwirtschaft, Kassel Univ. (Gesamthochschule) (Germany)); Memmen, K. (Fachbereich Bauingenieurwesen, FG Siedlungswasserwirtschaft, Kassel Univ. (Gesamthochschule) (Germany))

    1994-09-01

    Within a scientific project especially the operation of four real-size sewage treatment plants with different processes of enhanced biological phosphorus removal is investigated under the aspect of efficiency, stability, practicability and costs of the enhanced biological phosphorus removal. Three plants and first results are explained and compared as well with one another as with data, which are generally regarded as favourable conditions for the enhanced biological phosphorus removal. Between the plants there are significant differences in the degree of P-elimination mainly due to different characteristics of the wastewater. An important influence on P-effluent concentrations may be exacted by P-resolution in the final clarifier. (orig.)

  17. Facile synthesis of phosphorus doped graphitic carbon nitride polymers with enhanced visible-light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ligang [Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Xiufang; Guan, Jing; Jiang, Yijun; Hou, Tonggang [Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Mu, Xindong, E-mail: muxd@qibebt.ac.cn [Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)

    2013-09-01

    Graphical abstract: - Highlights: • P-doped g-C{sub 3}N{sub 4} has been prepared by a one-pot green synthetic approach. • The incorporation of P resulted in favorable textural and electronic properties. • Doping with P enhanced the visible-light photocatalytic activity of g-C{sub 3}N{sub 4}. • A postannealing treatment further enhanced the activity of P-doped g-C{sub 3}N{sub 4}. • Photogenerated holes were the main species responsible for the activity. - Abstract: Phosphorus-doped carbon nitride materials were prepared by a one-pot green synthetic approach using dicyandiamide monomer and a phosphorus containing ionic liquid as precursors. The as-prepared materials were subjected to several characterizations and investigated as metal-free photocatalysts for the degradation of organic pollutants (dyes like Rhodamine B, Methyl orange) in aqueous solution under visible light. Results revealed that phosphorus-doped carbon nitride have a higher photocatalytic activity for decomposing Rhodamine B and Methyl orange in aqueous solution than undoped g-C{sub 3}N{sub 4}, which was attributed to the favorable textural, optical and electronic properties caused by doping with phosphorus heteroatoms into carbon nitride host. A facile postannealing treatment further improved the activity of the photocatalytic system, due to the higher surface area and smaller structural size in the postcalcined catalysts. The phosphorus-doped carbon nitride showed high visible-light photocatalytic activity, making them promising materials for a wide range of potential applications in photochemistry.

  18. Enhancing anaerobic digestibility and phosphorus recovery of dairy manure through microwave-based thermochemical pretreatment.

    Science.gov (United States)

    Jin, Ying; Hu, Zhenhu; Wen, Zhiyou

    2009-08-01

    Anaerobic digestion and struvite precipitation are two effective ways of treating dairy manure for recovering biogas and phosphorus. Anaerobic digestion of dairy manure is commonly limited by slow fiber degradation, while struvite precipitation is limited by the availability of orthophosphate. The aim of this work is to study the possibility of using microwave-based thermochemical pretreatment to simultaneously enhance manure anaerobic digestibility (through fiber degradation) and struvite precipitation (through phosphorus solubilization). Microwave heating combined with different chemicals (NaOH, CaO, H(2)SO(4), or HCl) enhanced solubilization of manure and degradation of glucan/xylan in dairy manure. However, sulfuric acid-based pretreatment resulted in a low anaerobic digestibility, probably due to the sulfur inhibition and Maillard side reaction. The pretreatments released 20-40% soluble phosphorus and 9-14% ammonium. However, CaO-based pretreatment resulted in lower orthophosphate releases and struvite precipitation efficiency as calcium interferes with phosphate to form calcium phosphate. Collectively, microwave heating combined with NaOH or HCl led to a high anaerobic digestibility and phosphorus recovery. Using these two chemicals, the performance of microwave- and conventional-heating in thermochemical pretreatment was further compared. The microwave heating resulted in a better performance in terms of COD solubilization, glucan/xylan reduction, phosphorus solubilization and anaerobic digestibility. Lastly, temperature and heating time used in microwave treatment were optimized. The optimal values of temperature and heating time were 147 degrees C and 25.3 min for methane production, and 135 degrees C and 26 min for orthophosphate release, respectively. PMID:19555991

  19. A metabolic model for members of the genus Tetrasphaera involved in enhanced biological phosphorus removal

    OpenAIRE

    Kristiansen, Rikke; Nguyen, Hien Thi Thu; Saunders, Aaron Marc; Nielsen, Jeppe Lund; Wimmer, Reinhard; Le, Vang Quy; McIlroy, Simon Jon; Petrovski, Steve; Seviour, Robert J.; Calteau, Alexandra; Nielsen, Kåre Lehmann; Nielsen, Per Halkjær

    2012-01-01

    Members of the genus Tetrasphaera are considered to be putative polyphosphate accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) from wastewater. Although abundant in Danish full-scale wastewater EBPR plants, how similar their ecophysiology is to ‘Candidatus Accumulibacter phosphatis' is unclear, although they may occupy different ecological niches in EBPR communities. The genomes of four Tetrasphaera isolates (T. australiensis, T. japonica, T. elongata and T. jenk...

  20. Dynamics of Intracellular Polymers in Enhanced Biological Phosphorus Removal Processes under Different Organic Carbon Concentrations

    OpenAIRE

    Lizhen Xing; Li Ren; Bo Tang,; Guangxue Wu; Yuntao Guan

    2013-01-01

    Enhanced biological phosphorus removal (EBPR) may deteriorate or fail during low organic carbon loading periods. Polyphosphate accumulating organisms (PAOs) in EBPR were acclimated under both high and low organic carbon conditions, and then dynamics of polymers in typical cycles, anaerobic conditions with excess organic carbons, and endogenous respiration conditions were examined. After long-term acclimation, it was found that organic loading rates did not affect the yield of PAOs and the app...

  1. Enhancing phosphorus recovery by a new internal recycle seeding MAP reactor.

    Science.gov (United States)

    Liu, Zhigang; Zhao, Qingliang; Lee, Duu-Jong; Yang, Nan

    2008-09-01

    Phosphorus is a depleting resource that needs recovery from wastewater streams. The magnesium ammonium phosphate (MAP) crystallization process could simultaneously recover ammonium nitrogen and phosphorus at equal molar basis to yield slow-release MAP fertilizer. However, the present MAP processes are not efficient in recovering phosphorus at low P concentrations. This work presented and tested the performance of a newly proposed MAP reactor, the internal recycle seeding reactor (IRSR) that comprised of a reaction zone and a settling zone connecting with an internal recirculation loop. Owing to the enhanced secondary nucleation rates of MAP crystals in reaction zone under controlled circumstance, the proposed IRSR recovered 78% of phosphorus from wastewater at a low level of 21.7 mg-PL(-1). The optimal operation parameters for the IRSR were investigated with synthetic wastewater and determined as that the Mg/PO(4)(3-)-P molar ratio was 1.3-1.5:1, THRT was up to or longer than 1.14 h, the seed concentration of reaction zone was 0.40-1.0 gL(-1). Further needs for the proposed IRSR strategies were also discussed. PMID:18187321

  2. Passivation of hematite nanorod photoanodes with a phosphorus overlayer for enhanced photoelectrochemical water oxidation

    Science.gov (United States)

    Xiong, Dehua; Li, Wei; Wang, Xiaoguang; Liu, Lifeng

    2016-09-01

    Hematite (i.e., α-Fe2O3) nanorod photoanodes passivated with a phosphorus overlayer have been fabricated by decomposing sodium hypophosphite (NaH2PO2) at a low temperature over the hematite nanorod surface. Extensive scanning electron microscopy, transmission electron microscopy, x-ray diffractometry and UV–vis spectroscopy characterizations confirm that conformal deposition of an amorphous phosphorus overlayer does not change the crystal structure, morphology, and optical absorption properties of hematite photoanodes. X-ray photoelectron spectroscopy reveals that phosphorus in the deposited overlayer exists in an oxidized state. Comprehensive steady-state polarization, transient photocurrent response, and impedance spectroscopy measurements as well as Mott–Schottky analysis manifest that the phosphorus overlayer is able to effectively passivate surface states and suppress electron–hole recombination, substantially enhancing the photocurrent for water oxidation. Combining the phosphorization treatment with two-step thermal activation, a photocurrent density of 1.1 mA cm‑2 is achieved at 1.23 V versus reversible hydrogen electrode under illumination of 100 mW cm‑2, ca 55 times higher than that of the non-activated pristine hematite photoanode measured under the same conditions. The simple and fast phosphorization strategy we present here can be readily applied to passivate surfaces of other semiconductor photoelectrodes to improve their photoelectrochemical performance.

  3. Passivation of hematite nanorod photoanodes with a phosphorus overlayer for enhanced photoelectrochemical water oxidation

    Science.gov (United States)

    Xiong, Dehua; Li, Wei; Wang, Xiaoguang; Liu, Lifeng

    2016-09-01

    Hematite (i.e., α-Fe2O3) nanorod photoanodes passivated with a phosphorus overlayer have been fabricated by decomposing sodium hypophosphite (NaH2PO2) at a low temperature over the hematite nanorod surface. Extensive scanning electron microscopy, transmission electron microscopy, x-ray diffractometry and UV-vis spectroscopy characterizations confirm that conformal deposition of an amorphous phosphorus overlayer does not change the crystal structure, morphology, and optical absorption properties of hematite photoanodes. X-ray photoelectron spectroscopy reveals that phosphorus in the deposited overlayer exists in an oxidized state. Comprehensive steady-state polarization, transient photocurrent response, and impedance spectroscopy measurements as well as Mott-Schottky analysis manifest that the phosphorus overlayer is able to effectively passivate surface states and suppress electron-hole recombination, substantially enhancing the photocurrent for water oxidation. Combining the phosphorization treatment with two-step thermal activation, a photocurrent density of 1.1 mA cm-2 is achieved at 1.23 V versus reversible hydrogen electrode under illumination of 100 mW cm-2, ca 55 times higher than that of the non-activated pristine hematite photoanode measured under the same conditions. The simple and fast phosphorization strategy we present here can be readily applied to passivate surfaces of other semiconductor photoelectrodes to improve their photoelectrochemical performance.

  4. Enhancing of catalytic properties of vanadia via surface doping with phosphorus using atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Strempel, Verena E.; Naumann d' Alnoncourt, Raoul, E-mail: r.naumann@bascat.tu-berlin.de [BasCat - UniCat BASF JointLab, Technische Universität Berlin, Sekr. EW K 01, Hardenbergstraße 36, 10623 Berlin (Germany); Löffler, Daniel [Process Research and Chemical Engineering, BASF SE, Carl-Bosch-Straße 38, 67056 Ludwigshafen (Germany); Kröhnert, Jutta; Skorupska, Katarzyna; Johnson, Benjamin [Department of Inorganic Chemistry, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Driess, Matthias [BasCat - UniCat BASF JointLab, Technische Universität Berlin, Sekr. EW K 01, Hardenbergstraße 36, 10623 Berlin, Germany and Technische Universität Berlin, Institut für Chemie, Sekr. C2, Straße des 17. Juni 135, 10623 Berlin (Germany); Rosowski, Frank [BasCat - UniCat BASF JointLab, Technische Universität Berlin, Sekr. EW K 01, Hardenbergstraße 36, 10623 Berlin, Germany and Process Research and Chemical Engineering, BASF SE, Carl-Bosch-Straße 38, 67056 Ludwigshafen (Germany)

    2016-01-15

    Atomic layer deposition is mainly used to deposit thin films on flat substrates. Here, the authors deposit a submonolayer of phosphorus on V{sub 2}O{sub 5} in the form of catalyst powder. The goal is to prepare a model catalyst related to the vanadyl pyrophosphate catalyst (VO){sub 2}P{sub 2}O{sub 7} industrially used for the oxidation of n-butane to maleic anhydride. The oxidation state of vanadium in vanadyl pyrophosphate is 4+. In literature, it was shown that the surface of vanadyl pyrophosphate contains V{sup 5+} and is enriched in phosphorus under reaction conditions. On account of this, V{sub 2}O{sub 5} with the oxidation state of 5+ for vanadium partially covered with phosphorus can be regarded as a suitable model catalyst. The catalytic performance of the model catalyst prepared via atomic layer deposition was measured and compared to the performance of catalysts prepared via incipient wetness impregnation and the original V{sub 2}O{sub 5} substrate. It could be clearly shown that the dedicated deposition of phosphorus by atomic layer deposition enhances the catalytic performance of V{sub 2}O{sub 5} by suppression of total oxidation reactions, thereby increasing the selectivity to maleic anhydride.

  5. A comparative study of the bacterial community in denitrifying and traditional enhanced biological phosphorus removal processes.

    Science.gov (United States)

    Lv, Xiao-Mei; Shao, Ming-Fei; Li, Chao-Lin; Li, Ji; Gao, Xin-Lei; Sun, Fei-Yun

    2014-09-17

    Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphorus removal rates being 87.9% and 89.0% respectively. The community structures in denitrifying and traditional EBPR processes were evaluated by high-throughput sequencing of the PCR-amplified partial 16S rRNA genes from each sludge. The results obtained showed that the bacterial community was more diverse in A-O sludge than in A-A sludge. Taxonomy and β-diversity analyses indicated that a significant shift occurred in the dominant microbial community in A-A sludge compared with the seed sludge during the whole acclimation phase, while a slight fluctuation was observed in the abundance of the major taxonomies in A-O sludge. One Dechloromonas-related OTU outside the 4 known Candidatus "Accumulibacter" clades was detected as the main OTU in A-A sludge at the stationary operation, while Candidatus "Accumulibacter" dominated in A-O sludge. PMID:24964811

  6. Roles of extracellular polymeric substances in enhanced biological phosphorus removal process.

    Science.gov (United States)

    Li, Wen-Wei; Zhang, Hai-Ling; Sheng, Guo-Ping; Yu, Han-Qing

    2015-12-01

    Enhanced biological phosphorus removal (EBPR) process is known to mainly rely on the ability of phosphorus-accumulating organisms to take up, transform and store excess amount of phosphorus (P) inside the cells. However, recent studies have revealed considerable accumulation of P also in the extracellular polymeric substances (EPS) of sludge, implying a non-negligible role of EPS in P removal by EBPR sludge. However, the contribution of EPS to P uptake and the forms of accumulated extracellular P vary substantially in different studies, and the underlying mechanism of P transformation and transportation in EPS remains poorly understood. This review provides a new recognition into the P removal process in EBPR system by incorporating the role of EPS. It overviews on the characteristics of P accumulation in EPS, explores the mechanism of P transformation and transportation in EBPR sludge and EPS, summarizes the main influential factors for the P-accumulation properties of EPS, and discusses the remaining knowledge gaps and needed future efforts that may lead to better understanding and use of such an EPS role for maximizing P recovery from wastewater. PMID:26143588

  7. Enhanced Biological Phosphorus Removal in SBR Using Glucose as a Single Organic Substrate

    Institute of Scientific and Technical Information of China (English)

    JIANG Yi-feng; LI Xiang-kun; FENG Xiao-yu; WANG Shu-tao; WANG Bao-zhen; LIU Ya-nan; CHEN Jian-meng

    2008-01-01

    Enhanced biological phosphorus removal (EBPR) was investigated in an anaerobic/aerobic sequencing batch reactor (SBR) supplied with glucose as a single organic substrate. The results illustrated that EBPR process could also occur successfully with glucose other than short chain fatty acids (SCFAs). High phosphorus release and polyhydroxyalkanoate (PHA) accumulation in the anaerobic phase was found vital for the removal of phosphorus during the aerobic phase. The measurement of intracellular reserves revealed that glycogen had a higher chance to replace the energy role of poly-P under anaerobic conditions. Moreover, glycogen was also utilized as the carbon source for PHA synthesis. as well as a reducing power as reported earlier. The accumulated PHA in this system was mainly in the form of poly-hydroxyvalerate (PHV) instead of polyhydroxybutyrate (PHB), and was inferred to be caused by the excess reducing power contained in glucose. Lactate as a fermentation product was also found released into the bulk solution. Applying fundamental biochemistry knowledge to the experimental results, a conceptual biochemical model was developed to explain the metabolism of the glucoseinduced EBPR.

  8. Integrative microbial community analysis reveals full-scale enhanced biological phosphorus removal under tropical conditions

    Science.gov (United States)

    Law, Yingyu; Kirkegaard, Rasmus Hansen; Cokro, Angel Anisa; Liu, Xianghui; Arumugam, Krithika; Xie, Chao; Stokholm-Bjerregaard, Mikkel; Drautz-Moses, Daniela I.; Nielsen, Per Halkjær; Wuertz, Stefan; Williams, Rohan B. H.

    2016-05-01

    Management of phosphorus discharge from human waste is essential for the control of eutrophication in surface waters. Enhanced biological phosphorus removal (EBPR) is a sustainable, efficient way of removing phosphorus from waste water without employing chemical precipitation, but is assumed unachievable in tropical temperatures due to conditions that favour glycogen accumulating organisms (GAOs) over polyphosphate accumulating organisms (PAOs). Here, we show these assumptions are unfounded by studying comparative community dynamics in a full-scale plant following systematic perturbation of operational conditions, which modified community abundance, function and physicochemical state. A statistically significant increase in the relative abundance of the PAO Accumulibacter was associated with improved EBPR activity. GAO relative abundance also increased, challenging the assumption of competition. An Accumulibacter bin-genome was identified from a whole community metagenomic survey, and comparative analysis against extant Accumulibacter genomes suggests a close relationship to Type II. Analysis of the associated metatranscriptome data revealed that genes encoding proteins involved in the tricarboxylic acid cycle and glycolysis pathways were highly expressed, consistent with metabolic modelling results. Our findings show that tropical EBPR is indeed possible, highlight the translational potential of studying competition dynamics in full-scale waste water communities and carry implications for plant design in tropical regions.

  9. Integrative microbial community analysis reveals full-scale enhanced biological phosphorus removal under tropical conditions

    Science.gov (United States)

    Law, Yingyu; Kirkegaard, Rasmus Hansen; Cokro, Angel Anisa; Liu, Xianghui; Arumugam, Krithika; Xie, Chao; Stokholm-Bjerregaard, Mikkel; Drautz-Moses, Daniela I.; Nielsen, Per Halkjær; Wuertz, Stefan; Williams, Rohan B. H.

    2016-01-01

    Management of phosphorus discharge from human waste is essential for the control of eutrophication in surface waters. Enhanced biological phosphorus removal (EBPR) is a sustainable, efficient way of removing phosphorus from waste water without employing chemical precipitation, but is assumed unachievable in tropical temperatures due to conditions that favour glycogen accumulating organisms (GAOs) over polyphosphate accumulating organisms (PAOs). Here, we show these assumptions are unfounded by studying comparative community dynamics in a full-scale plant following systematic perturbation of operational conditions, which modified community abundance, function and physicochemical state. A statistically significant increase in the relative abundance of the PAO Accumulibacter was associated with improved EBPR activity. GAO relative abundance also increased, challenging the assumption of competition. An Accumulibacter bin-genome was identified from a whole community metagenomic survey, and comparative analysis against extant Accumulibacter genomes suggests a close relationship to Type II. Analysis of the associated metatranscriptome data revealed that genes encoding proteins involved in the tricarboxylic acid cycle and glycolysis pathways were highly expressed, consistent with metabolic modelling results. Our findings show that tropical EBPR is indeed possible, highlight the translational potential of studying competition dynamics in full-scale waste water communities and carry implications for plant design in tropical regions. PMID:27193869

  10. Effects of Solid Retention Time (SRT) on Sludge Characteristics in Enhanced Biological Phosphorus Removal (EBPR) Reactor

    OpenAIRE

    Li, N.; X Wang; N Ren; Zhang, K.; Kang, H; You, S.

    2008-01-01

    This study investigated the effects of solid retention time (SRT) on sludge characteristics and operational performance in enhanced biological phosphorus removal (EBPR) reactor. The results showed that the reactor operated at SRT of τ = 8.3 d could achieve phosphate removal efficiency η > 90 % and SVI < 100 mL g–1. In comparison, increasing SRT to τ = 16.6 d led to a decrease of phosphate removal (η < 85 %) and an increase of SVI value (160 mL g–1), implying a performance degradation and wors...

  11. Present and perspective of enhanced biological phosphorus removal process; Seibutsugakuteki rin jokyoho no genjo to kadai

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K. [National Inst. of Bioscience and Human-Technology, Tsukuba (Japan)

    1997-02-05

    Biological phosphorus removal process utilizing anaerobic and aerobic conditions, mechanism of phosphorus removal, and microbes relating to phosphorus removal are outlined, and future problems are discussed. By mixing waste water and sludge under anaerobic condition followed by treatment under aerobic condition, phosphorus content in sludge increases to enable biological phosphorus removal. More microbes with high polyphosphorus accumulating performance are acquired by the anaerobic/aerobic process than other microbes with the result of their preferential increase, and the process has high phosphorus removal characteristic than the general treatment process. Microbes relating to phosphorus removal, immobilization of polyphosphate accumulating microbes, and phosphorus acquiring and releasing characteristics of immobilized mycelium are discussed. Application of gel entrapped immobilized mycelium to phosphorus removal and problems in biological phosphorus removing methods are described. 18 refs., 12 figs.

  12. Partitionable-space enhanced coagulation (PEC) reactor and its working mechanism: a new prospective chemical technology for phosphorus pollution control.

    Science.gov (United States)

    Zhang, Meng; Zheng, Ping; Abbas, Ghulam; Chen, Xiaoguang

    2014-02-01

    Phosphorus pollution control and phosphorus recycling, simultaneously, are focus of attention in the wastewater treatment. In this work, a novel reactor named partitionable-space enhanced coagulation (PEC) was invented for phosphorus control. The working performance and process mechanism of PEC reactor were investigated. The results showed that the PEC technology was highly efficient and cost-effective. The volumetric removal rate (VRR) reached up to 2.86 ± 0.04 kg P/(m(3) d) with a phosphorus removal rate of over 97%. The precipitant consumption was reduced to 2.60-2.76 kg Fe(II)/kg P with low operational cost of $ 0.632-0.673/kg P. The peak phosphorus content in precipitate was up to 30.44% by P2O5, which reveal the benefit of the recycling phosphorus resource. The excellent performance of PEC technology was mainly attributed to the partitionable-space and 'flocculation filter'. The partition limited the trans-regional back-mixing of reagents along the reactor, which promoted the precipitation reaction. The 'flocculation filter' retained the microflocs, enhancing the flocculation process.

  13. Understanding the role of extracellular polymeric substances in an enhanced biological phosphorus removal granular sludge system.

    Science.gov (United States)

    Wang, Randeng; Peng, Yongzhen; Cheng, Zhanli; Ren, Nanqi

    2014-10-01

    The role of extracellular polymeric substances (EPS) in the enhanced biological phosphorus removal (EBPR) process was investigated in a P-accumulating granular sludge system by analyzing the distribution and transfer of P, K(+), Mg(2+) and Ca(2+) in the sludge phase, EPS, and the bulk liquid. In the sludge phase, about 30% P, 44.7% K(+), 27.7% Mg(2+), 28% Ca(2+) accumulated in the EPS at the end of aeration. The rate of P, K(+), Mg(2+) and Ca(2+) released from the EPS matrix into the bulk liquid in the anaerobic phase was faster than the rate they were adsorbed from the bulk liquid into the EPS in the aerobic phase. P, K(+), Mg(2+) and Ca(2+) were retained in EPS before transferring into the phosphorus accumulating organisms (PAOs). These results suggest that EPS play a critical role in facilitating the accumulation and transfer of P, K(+), Ca(2+) and Mg(2+) between PAO cells and bulk liquid. PMID:25063972

  14. Impact of butyrate on microbial selection in enhanced biological phosphorus removal systems.

    Science.gov (United States)

    Begum, Shamim A; Batista, Jacimaria R

    2014-01-01

    Microbial selection in an enhanced biological phosphorus removal system was investigated in a laboratory-scale sequencing batch reactor fed exclusively with butyrate as a carbon source. As reported in the few previous studies, butyrate uptake was slow and phosphorus (P) release occurred during the entire anaerobic period. Polyphosphate-accumulating organism (PAO), i.e. Candidatus Accumulibacter phosphatis (named as Accumulibacter), glycogen-accumulating organisms (GAOs), i.e. Candidatus Competibacter phosphatis (named as Competibacter) and Defluviicoccus-related, tetrad-forming alphaproteobacteria (named as Defluviicoccus) were identified using fluorescence in situ hybridization analysis. The results show that Accumulibacter and Defluviicoccus were selected in the butyrate-fed reactor, whereas Competibacter was not selected. P removal was efficient at the beginning of the experiment with an increasing percentage relative abundance (% RA) of PAOs. The % RA of Accumulibacter and Defluviicoccus increased from 13% to 50% and 8% to 16%, respectively, and the % RA of Competibacter decreased from 8% to 2% during the experiment. After 6 weeks, P removal deteriorated with the poor correlation between the percentage of P removal and % RA of GAOs. PMID:25189844

  15. Rare taxa have potential to make metabolic contributions in enhanced biological phosphorus removal ecosystems.

    Science.gov (United States)

    Lawson, Christopher E; Strachan, Blake J; Hanson, Niels W; Hahn, Aria S; Hall, Eric R; Rabinowitz, Barry; Mavinic, Donald S; Ramey, William D; Hallam, Steven J

    2015-12-01

    Enhanced biological phosphorus removal (EBPR) relies on diverse but specialized microbial communities to mediate the cycling and ultimate removal of phosphorus from municipal wastewaters. However, little is known about microbial activity and dynamics in relation to process fluctuations in EBPR ecosystems. Here, we monitored temporal changes in microbial community structure and potential activity across each bioreactor zone in a pilot-scale EBPR treatment plant by examining the ratio of small subunit ribosomal RNA (SSU rRNA) to SSU rRNA gene (rDNA) over a 120 day study period. Although the majority of operational taxonomic units (OTUs) in the EBPR ecosystem were rare, many maintained high potential activities based on SSU rRNA : rDNA ratios, suggesting that rare OTUs contribute substantially to protein synthesis potential in EBPR ecosystems. Few significant differences in OTU abundance and activity were observed between bioreactor redox zones, although differences in temporal activity were observed among phylogenetically cohesive OTUs. Moreover, observed temporal activity patterns could not be explained by measured process parameters, suggesting that other ecological drivers, such as grazing or viral lysis, modulated community interactions. Taken together, these results point towards complex interactions selected for within the EBPR ecosystem and highlight a previously unrecognized functional potential among low abundance microorganisms in engineered ecosystems. PMID:25857222

  16. Metabolic versatility in full-scale wastewater treatment plants performing enhanced biological phosphorus removal.

    Science.gov (United States)

    Lanham, Ana B; Oehmen, Adrian; Saunders, Aaron M; Carvalho, Gilda; Nielsen, Per H; Reis, Maria A M

    2013-12-01

    This study analysed the enhanced biological phosphorus removal (EBPR) microbial community and metabolic performance of five full-scale EBPR systems by using fluorescence in situ hybridisation combined with off-line batch tests fed with acetate under anaerobic-aerobic conditions. The phosphorus accumulating organisms (PAOs) in all systems were stable and showed little variability between each plant, while glycogen accumulating organisms (GAOs) were present in two of the plants. The metabolic activity of each sludge showed the frequent involvement of the anaerobic tricarboxylic acid cycle (TCA) in PAO metabolism for the anaerobic generation of reducing equivalents, in addition to the more frequently reported glycolysis pathway. Metabolic variability in the use of the two pathways was also observed, between different systems and in the same system over time. The metabolic dynamics was linked to the availability of glycogen, where a higher utilisation of the glycolysis pathway was observed in the two systems employing side-stream hydrolysis, and the TCA cycle was more active in the A(2)O systems. Full-scale plants that showed higher glycolysis activity also exhibited superior P removal performance, suggesting that promotion of the glycolysis pathway over the TCA cycle could be beneficial towards the optimisation of EBPR systems.

  17. Population dynamics of bacteria involved in enhanced biological phosphorus removal in Danish wastewater treatment plants.

    Science.gov (United States)

    Mielczarek, Artur Tomasz; Nguyen, Hien Thi Thu; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

    2013-03-15

    The enhanced biological phosphorus removal (EBPR) process is increasingly popular as a sustainable method for removal of phosphorus (P) from wastewater. This study consisted of a comprehensive three-year investigation of the identity and population dynamics of polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in 28 Danish municipal wastewater treatment plants with nutrient removal. Fluorescence in situ hybridization was applied to quantify ten probe-defined populations of PAO and GAO that in total constituted a large fraction (30% on average) of the entire microbial community targeted by the EUBmix probes. Two PAO genera, Accumulibacter and Tetrasphaera, were very abundant in all EBPR plants (average of 3.7% and 27% of all bacteria, respectively), and their abundance was relatively stable in the Danish full-scale plants without clear temporal variations. GAOs were occasionally present in some plants (Competibacter in 11 plants, Defluviicoccus in 6 plants) and were consistent in only a few plants. This shows that these were not core species in the EBPR communities. The total GAO abundance was always lower than that of Accumulibacter. In plants without EBPR design, the abundance of PAO and GAO was significantly lower. Competibacter correlated in general with high fraction of industrial wastewater. In specific plants Accumulibacter correlated with high C/P ratio of the wastewater and Tetrasphaera with high organic loading. Interestingly, the relative microbial composition of the PAO/GAO species was unique to each plant over time, which gives a characteristic plant-specific "fingerprint".

  18. Functionally relevant microorganisms to enhanced biological phosphorus removal performance at full-scale wastewater treatment plants in the United States.

    Science.gov (United States)

    Gu, April Z; Saunders, A; Neethling, J B; Stensel, H D; Blackall, L L

    2008-08-01

    The abundance and relevance ofAccumulibacter phosphatis (presumed to be polyphosphate-accumulating organisms [PAOs]), Competibacter phosphatis (presumed to be glycogen-accumulating organisms [GAOs]), and tetrad-forming organisms (TFOs) to phosphorus removal performance at six full-scale enhanced biological phosphorus removal (EBPR) wastewater treatment plants were investigated. Coexistence of various levels of candidate PAOs and GAOs were found at these facilities. Accumulibacter were found to be 5 to 20% of the total bacterial population, and Competibacter were 0 to 20% of the total bacteria population. The TFO abundance varied from nondetectable to dominant. Anaerobic phosphorus (P) release to acetate uptake ratios (P(rel)/HAc(up)) obtained from bench tests were correlated positively with the abundance ratio of Accumulibacter/(Competibacter +TFOs) and negatively with the abundance of (Competibacter +TFOs) for all plants except one, suggesting the relevance of these candidate organisms to EBPR processes. However, effluent phosphorus concentration, amount of phosphorus removed, and process stability in an EBPR system were not directly related to high PAO abundance or mutually exclusive with a high GAO fraction. The plant that had the lowest average effluent phosphorus and highest stability rating had the lowest P(rel)/HAc(up) and the most TFOs. Evaluation of full-scale EBPR performance data indicated that low effluent phosphorus concentration and high process stability are positively correlated with the influent readily biodegradable chemical oxygen demand-to-phosphorus ratio. A system-level carbon-distribution-based conceptual model is proposed for capturing the dynamic competition between PAOs and GAOs and their effect on an EBPR process, and the results from this study seem to support the model hypothesis. PMID:18751532

  19. Dynamics of Intracellular Polymers in Enhanced Biological Phosphorus Removal Processes under Different Organic Carbon Concentrations

    Directory of Open Access Journals (Sweden)

    Lizhen Xing

    2013-01-01

    Full Text Available Enhanced biological phosphorus removal (EBPR may deteriorate or fail during low organic carbon loading periods. Polyphosphate accumulating organisms (PAOs in EBPR were acclimated under both high and low organic carbon conditions, and then dynamics of polymers in typical cycles, anaerobic conditions with excess organic carbons, and endogenous respiration conditions were examined. After long-term acclimation, it was found that organic loading rates did not affect the yield of PAOs and the applied low organic carbon concentrations were advantageous for the enrichment of PAOs. A low influent organic carbon concentration induced a high production of extracellular carbohydrate. During both anaerobic and aerobic endogenous respirations, when glycogen decreased to around 80 ± 10 mg C per gram of volatile suspended solids, PAOs began to utilize polyphosphate significantly. Regressed by the first-order reaction model, glycogen possessed the highest degradation rate and then was followed by polyphosphate, while biomass decay had the lowest degradation rate.

  20. Microbiological study of bacteriophage induction in the presence of chemical stress factors in enhanced biological phosphorus removal (EBPR).

    Science.gov (United States)

    Motlagh, Amir Mohaghegh; Bhattacharjee, Ananda S; Goel, Ramesh

    2015-09-15

    Polyphosphate accumulating organisms (PAOs) are responsible for carrying the enhanced biological phosphorus removal (EBPR). Although the EBPR process is well studied, the failure of EBPR performance at both laboratory and full-scale plants has revealed a lack of knowledge about the ecological and microbiological aspects of EBPR processes. Bacteriophages are viruses that infect bacteria as their sole host. Bacteriophage infection of polyphosphate accumulating organisms (PAOs) has not been considered as a main contributor to biological phosphorus removal upsets. This study examined the effects of different stress factors on the dynamics of bacteriophages and the corresponding effects on the phosphorus removal performance in a lab-scale EBPR system. The results showed that copper (heavy metal), cyanide (toxic chemical), and ciprofloxacin (antibiotic), as three different anthropogenic stress factors, can induce phages integrated onto bacterial genomes (i.e. prophages) in an enriched EBPR sequencing batch reactor, resulting in a decrease in the polyphosphate kinase gene ppk1 clades copy number, phosphorus accumulation capacity, and phosphorus removal performance. This study opens opportunities for further research on the effects of bacteriophages in nutrient cycles both in controlled systems such as wastewater treatment plants and natural ecosystems. PMID:26024959

  1. Effect of Sludge Type on Enhanced Biological Phosphorus Removal in Sequencing Batch Reactors

    Science.gov (United States)

    Li, Xing; Gao, Dawen; Zhang, Baihui

    2010-11-01

    Aerobic granulation technology has become a novel biotechnology for wastewater treatment. However, the study of distinct properties and characteristics of phosphorus removal between granules and flocculent sludge are still sparse in EBPR. Two SBRs were concurrently operated to investigate the different phosphorus removal characteristics between granules (R1) and flocculate sludge (R2). Results indicated that R2 had a faster progress for enriching phosphorus-accumulating organisms compared with R1, and the phosphorus removal reached the steady state after 40 days in R1 but only 30 days in R2. The moisture content of granules (85.63%) was smaller than that (91.36%) in R2, and the granules had a higher removal efficiency of NH4+-N. However, flocculent sludge could release and take up more phosphorus. The special phosphorus release rate (SPRR) and special phosphorus uptake rate (SPUR) were 8.818 mg/gVSSṡh and 9.921 mg/gVSSṡh in R2 which were consistently larger than that (0.999 mg/gVSSṡh and 0.754 mg/gVSSṡh) in R1. The results of DGGE of PCR-amplified 16SrDNA fragments revealed that the diversity and the amount of phosphorus accumulating microbial of bacteria in flocculent sludge were much more than that in the granules. It can be concluded that the flocculent sludge showed a better phosphorus removal.

  2. Intensifying enhanced biological phosphorus removal by calciumdolomitehydrate; Intensivierung der vermehrten biologischen Phosphatelimination durch Dolomitkalkhydrat

    Energy Technology Data Exchange (ETDEWEB)

    Soelter, M. [AKDOLIT GmbH, Wuelfrath (Germany)

    1999-02-01

    Utilization of enhanced biological phosphorus removal is increasingly considered an essential part in designing wastewater treatment plant due to ecological and economical advantages. Effects of Akdophos (=special dolime-hydrate) were investigated and monitored in operational tests at the industrial effluent clarification plant of Gerolsteiner Brunnen and the municipal plant Dremmen. Results of a full year cyclus demonstrate the efficiency of Akdophos in stabilizing and intensifying the enhanced Bio-P removal. Cost-analysis shows a considerable cost cutting potential regarding precipitants as well as improvement of sludge volume index with only low increase of excess sludge. Dry product dosage of Akdophos to the aeration tank has been proved a reliable and cost-effective process method. (orig.) [Deutsch] Oekokogische und oekonomische Vorteile bestaetigen zunehmend die Nutzung der erweiterten biologischen Phosphatelimination als wesentlichen Bestandteil der Konzeption von Abwasserreinigungsanlagen. Anhand grosstechnischer Versuche auf der Klaeranlage des Gerolsteiner Brunnen und auf der Klaeranlage Dremmen (Stadt Heinsberg) wurde die Wirkung von Akdorphos (=speziell hergestelltes Dolomitkalkhydrat) auf die biologischen Vorgaenge von Klaeranlagen untersucht. Im Betrieb ueber einen vollstaendigen Jahreszyklus konnte nachgewiesen werden, dass die biologische Phosphatelimination durch eine geringfuegige Dosierung von Akdophos intensiviert und stabilisiert wird. Die Kostenanalyse in beiden betrachteten Faellen zeigt neben einer Kostenreduktion bei den Faellmitteln weitere Einsparungen durch deutlich verbesserte Schlammabsetzeigenschaften bei sehr geringem Schlammehranfall. Die Dosierung von Akdophos erfolgt vorzugsweise trocken und unmittelbar in die Belebung. Die entsprechende Anlagentechnik hat sich als betriebssicher und kostenguenstig erwiesen. (orig.)

  3. Effects of transgenic soybean on growth and phosphorus acquisition in mixed culture system

    Institute of Scientific and Technical Information of China (English)

    Jianna Xie; Jia Zhou; Xiurong Wang; Hong Liao

    2015-01-01

    Transgenic soybean plants overexpressing the Arabidopsis purple acid phosphatase gene AtPAP15 (OXp) or the soybean expansin gene GmEXPB2 (OXe) can improve phosphorous (P) efficiency in pure culture by increasing Apase secretion or changing root morphology. In this study, soybean‐soybean mixed cultures were employed to il uminate P acquisition among plants in mixed stands of transgenic and wild‐type soybean. Our results showed that transgenic soybean plants were much more competitive, and had greater growth and P uptake than wild‐type soybean in mixed culture in both low P calcareous and acid soils. Furthermore, OXe plants had an advantage in calcareous soils when mixed with OXp, whereas the latter performed much better in acid soils. In soybean‐maize mixed culture, transgenic soybean had no impact on maize growth compared to controls in both acid and calcareous soils with different P conditions. As for soybean in mixed culture, OXp plants had no significant advantages regardless of P availability or soil type, while P efficiency improved in OXe in calcareous soils compared to controls. These results imply that physiological traits could be easily affected by the mixed maize. Transgenic soybean plants with enhanced root traits had more competitive advantages than those with improved root physiology in mixed culture.

  4. Effects of COD to Phosphorus Ratios on the Metabolism of PAOs in Enhanced Biological Phosphorus Removal with Different Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    Tao Jiang; Junguo He; Xiaonan Yang; Jianzheng Li

    2015-01-01

    To elucidate the phosphorus removal and metabolism under various COD/P ratio, a sludge highly enriched in PAOs was used to investigate the impacts of COD/P in batch tests under different carbon supply conditions. Acetate, propionate and a mixture of acetate and propionate at a ratio of 3 ∶ 1 ( COD basis) was used as carbon sources with the COD/P of 20, 15,10 and 5�0 gCOD/gP, respectively. The minimum COD/P ratios for complete P removal were found to be 8�24 gCOD/gP for acetate, 11�40 gCOD/gP for propionate and 9�10 gCOD/gP for the 3 ∶ 1 mixture of acetate and propionate. Converted to a mass basis, all three cases had a very similar ratio of 7�7 gVFA/gP, which represented a useful guide for operation of EBPR plants to identify possible shortages inVFAs. The trend in PHV accumulation during the anaerobic period along with the decrease of COD/P ratios suggested that, PAOs may use the TCA pathway for anaerobic VFA uptake to maintain the required NADH production with reduced glycogen degradation. During the aerobic phase, the glycogen pool was reduced but remained enough compared to the requirement for anaerobic VFA uptake, and the synthesis and degradation of glycogen was not the inhibition factor of PAOs.

  5. Using the activated sludge model 2d (ASM2d) to understand and predict the phosphorus accumulating organisms mechanism in enhanced biological phosphorus removal in relation to disintegrated sludge as a carbon source

    OpenAIRE

    Boontian, Nittaya

    2012-01-01

    Carbon sources are considered as one of the most important factors in the performance of enhanced biological phosphorus removal (EBPR). Disintegrated sludge (DS) can act as carbon source to increase the efficiency of EBPR. This research explores the influence of DS upon phosphorus removal efficiency using mathematical simulation modeling. Activated Sludge Model No. 2d (ASM2d) is one of the most useful of activated sludge (AS) models. This is because ASM2d can express the integrated mechanisms...

  6. Enhanced phosphorus recovery and biofilm microbial community changes in an alternating anaerobic/aerobic biofilter.

    Science.gov (United States)

    Tian, Qing; Ong, Say Kee; Xie, Xuehui; Li, Fang; Zhu, Yanbin; Wang, Feng Rui; Yang, Bo

    2016-02-01

    The operation of an alternating anaerobic/aerobic biofilter (AABF), treating synthetic wastewater, was modified to enhance recovery of phosphorus (P). The AABF was periodically fed with an additional carbon source during the anaerobic phase to force the release of biofilm-sequestered P which was then harvested and recovered. A maximum of 48% of the total influent P was found to be released in the solution for recovery. Upon implementation of periodic P bio-sequestering and P harvesting, the predominant bacterial communities changed from β-Proteobacteria to γ-Proteobacteria groups. The genus Pseudomonas of γ-Proteobacteria was found to enrich greatly with 98% dominance. Dense intracellular poly-P granules were found within the cells of the biofilm, confirming the presence of P accumulating organisms (PAOs). Periodic addition of a carbon source to the AABF coupled with intracellular P reduction during the anaerobic phase most probably exerted environmental stress in the selection of Pseudomonas PAOs over PAOs of other phylogenic types. Results of the study provided operational information on the selection of certain microbial communities for P removal and recovery. This information can be used to further advance P recovery in biofilm systems such as the AABFs.

  7. Addition of anaerobic tanks to an oxidation ditch system to enhance removal of phosphorus from wastewater

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The oxidation ditch has been used for many years all over the world as an economic and efficient wastewater treatment technology. It can remove COD, nitrogen and a part of phosphorus efficiently. In the experiment described, a pilot scale Pasveer oxidation ditch system has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that influent total phosphorus(TP) was removed for 35% -50%. After this, two anaerobic tanks with total volume of 11 m3 were added to the system to release phosphorus. As a result, the TP removal efficiency increased by about 20%. At an anaerobic HRT of about 6 hours, a TP removal efficiency of 71 % was achieved.

  8. Enhanced biological phosphorus removal. Carbon sources, nitrate as electron acceptor, and characterization of the sludge community

    Energy Technology Data Exchange (ETDEWEB)

    Christensson, M.

    1997-10-01

    Enhanced biological phosphorus removal (EBPR) was studied in laboratory scale experiments as well as in a full scale EBPR process. The studies were focused on carbon source transformations, the use of nitrate as an electron acceptor and characterisation of the microflora. A continuous anaerobic/aerobic laboratory system was operated on synthetic wastewater with acetate as sole carbon source. An efficient EBPR was obtained and mass balances over the anaerobic reactor showed a production of 1.45 g poly-{beta}-hydroxyalcanoic acids (PHA), measured as chemical oxygen demand (COD), per g of acetic acid (as COD) taken up. Furthermore, phosphate was released in the anaerobic reactor in a ratio of 0.33 g phosphorus (P) per g PHA (COD) formed and 0.64 g of glycogen (COD) was consumed per g of acetic acid (COD) taken up. Microscopic investigations revealed a high amount of polyphosphate accumulating organisms (PAO) in the sludge. Isolation and characterisation of bacteria indicated Acinetobacter spp. to be abundant in the sludge, while sequencing of clones obtained in a 16S rDNA clone library showed a large part of the bacteria to be related to the high mole % G+C Gram-positive bacteria and only a minor fraction to be related to the gamma-subclass of proteobacteria to which Acinetobacter belongs. Operation of a similar anaerobic/aerobic laboratory system with ethanol as sole carbon source showed that a high EBPR can be achieved with this compound as carbon source. However, a prolonged detention time in the anaerobic reactor was required. PHA were produced in the anaerobic reactor in an amount of 1.24 g COD per g of soluble DOC taken up, phosphate was released in an amount of 0.4-0.6 g P per g PHA (COD) produced and 0.46 g glycogen (COD) was consumed per g of soluble COD taken up. Studies of the EBPR in the UCT process at the sewage treatment plant in Helsingborg, Sweden, showed the amount of volatile fatty acids (VFA) available to the PAO in the anaerobic stage to be

  9. Long-term study on the impact of temperature on enhanced biological phosphorus and nitrogen removal in membrane bioreactor.

    Science.gov (United States)

    Sayi-Ucar, N; Sarioglu, M; Insel, G; Cokgor, E U; Orhon, D; van Loosdrecht, M C M

    2015-11-01

    The study involved experimental observation and performance evaluation of a membrane bioreactor system treating municipal wastewater for nutrient removal for a period 500 days, emphasizing the impact of high temperature on enhanced biological phosphorus removal (EBPR). The MBR system was operated at relatively high temperatures (24-41 °C). During the operational period, the total phosphorus (TP) removal gradually increased from 50% up to 95% while the temperature descended from 41 to 24 °C. At high temperatures, anaerobic volatile fatty acid (VFA) uptake occurred with low phosphorus release implying the competition of glycogen accumulating organisms (GAOs) with polyphosphate accumulating organisms (PAOs). Low dissolved oxygen conditions associated with high wastewater temperatures did not appreciable affected nitrification but enhanced nitrogen removal. Dissolved oxygen levels around 1.0 mgO2/L in membrane tank provided additional denitrification capacity of 6-7 mgN/L by activating simultaneous nitrification and denitrification. As a result, nearly complete removal of nitrogen could be achieved in the MBR system, generating a permeate with no appreciable nitrogen content. The gross membrane flux was 43 LMH corresponding to the specific permeability (K) of 413 LMH/bar at 39 °C in the MBR tank. The specific permeability increased by the factor of 43% at 39 °C compared to that of 25 °C during long-term operation. PMID:26204227

  10. Metabolic modelling of full-scale enhanced biological phosphorus removal sludge.

    Science.gov (United States)

    Lanham, Ana B; Oehmen, Adrian; Saunders, Aaron M; Carvalho, Gilda; Nielsen, Per H; Reis, Maria A M

    2014-12-01

    This study investigates, for the first time, the application of metabolic models incorporating polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) towards describing the biochemical transformations of full-scale enhanced biological phosphorus removal (EBPR) activated sludge from wastewater treatment plants (WWTPs). For this purpose, it was required to modify previous metabolic models applied to lab-scale systems by incorporating the anaerobic utilisation of the TCA cycle and the aerobic maintenance processes based on sequential utilisation of polyhydroxyalkanoates, followed by glycogen and polyphosphate. The abundance of the PAO and GAO populations quantified by fluorescence in situ hybridisation served as the initial conditions of each biomass fraction, whereby the models were able to describe accurately the experimental data. The kinetic rates were found to change among the four different WWTPs studied or even in the same plant during different seasons, either suggesting the presence of additional PAO or GAO organisms, or varying microbial activities for the same organisms. Nevertheless, these variations in kinetic rates were largely found to be proportional to the difference in acetate uptake rate, suggesting a viable means of calibrating the metabolic model. The application of the metabolic model to full-scale sludge also revealed that different Accumulibacter clades likely possess different acetate uptake mechanisms, as a correlation was observed between the energetic requirement for acetate transport across the cell membrane with the diversity of Accumulibacter present. Using the model as a predictive tool, it was shown that lower acetate concentrations in the feed as well as longer aerobic retention times favour the dominance of the TCA metabolism over glycolysis, which could explain why the anaerobic TCA pathway seems to be more relevant in full-scale WWTPs than in lab-scale systems. PMID:25222332

  11. Heterogeneity of intracellular polymer storage states in enhanced biological phosphorus removal (EBPR)--observation and modeling.

    Science.gov (United States)

    Bucci, Vanni; Majed, Nehreen; Hellweger, Ferdi L; Gu, April Z

    2012-03-20

    A number of agent-based models (ABMs) for biological wastewater treatment processes have been developed, but their skill in predicting heterogeneity of intracellular storage states has not been tested against observations due to the lack of analytical methods for measuring single-cell intracellular properties. Further, several mechanisms can produce and maintain heterogeneity (e.g., different histories, uneven division) and their relative importance has not been explored. This article presents an ABM for the enhanced biological phosphorus removal (EBPR) treatment process that resolves heterogeneity in three intracellular polymer storage compounds (i.e., polyphosphate, polyhydroxybutyrate, and glycogen) in three functional microbial populations (i.e., polyphosphate-accumulating, glycogen-accumulating, and ordinary heterotrophic organisms). Model predicted distributions were compared to those based on single-cell estimates obtained using a Raman microscopy method for a laboratory-scale sequencing batch reactor (SBR) system. The model can reproduce many features of the observed heterogeneity. Two methods for introducing heterogeneity were evaluated. First, biological variability in individual cell behavior was simulated by randomizing model parameters (e.g., maximum acetate uptake rate) at division. This method produced the best fit to the data. An optimization algorithm was used to determine the best variability (i.e., coefficient of variance) for each parameter, which suggests large variability in acetate uptake. Second, biological variability in individual cell states was simulated by randomizing state variables (e.g., internal nutrient) at division, which was not able to maintain heterogeneity because the memory in the internal states is too short. These results demonstrate the ability of ABM to predict heterogeneity and provide insights into the factors that contribute to it. Comparison of the ABM with an equivalent population-level model illustrates the effect

  12. First-principles study of hydrogen-enhanced phosphorus diffusion in silicon

    Energy Technology Data Exchange (ETDEWEB)

    The Anh, Le, E-mail: letheanh@jaist.ac.jp; Lam, Pham Tien; Manoharan, Muruganathan; Matsumura, Hideki; Otsuka, Nobuo; Hieu Chi, Dam [School of Materials Science, Japan Advanced Institute of Science and Technology, Asahidai 1-1, Nomishi, Ishikawa 923-1292 (Japan); Tien Cuong, Nguyen [Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi (Viet Nam); Mizuta, Hiroshi [School of Materials Science, Japan Advanced Institute of Science and Technology, Asahidai 1-1, Nomishi, Ishikawa 923-1292 (Japan); Nanoelectronics and Nanotechnologies Research Group, Electronics and Computer Science, Faculty of Physical Sciences and Engineering, University of Southampton, Highfield, Southampton, Hampshire SO17 1BJ (United Kingdom)

    2016-01-28

    We present a first-principles study on the interstitial-mediated diffusion process of neutral phosphorus (P) atoms in a silicon crystal with the presence of mono-atomic hydrogen (H). By relaxing initial Si structures containing a P atom and an H atom, we derived four low-energy P-H-Si defect complexes whose formation energies are significantly lower than those of P-Si defect complexes. These four defect complexes are classified into two groups. In group A, an H atom is located near a Si atom, whereas in group B, an H atom is close to a P atom. We found that the H atom pairs with P or Si atom and changes the nature bonding between P and Si atoms from out-of-phase conjugation to in-phase conjugation. This fact results in the lower formation energies compare to the cases without H atom. For the migration of defect complexes, we have found that P-H-Si defect complexes can migrate with low barrier energies if an H atom sticks to either P or Si atom. Group B complexes can migrate from one lattice site to another with an H atom staying close to a P atom. Group A complexes cannot migrate from one lattice site to another without a transfer of an H atom from one Si atom to another Si atom. A change in the structure of defect complexes between groups A and B during the migration results in a transfer of an H atom between P and Si atoms. The results for diffusion of group B complexes show that the presence of mono-atomic H significantly reduces the activation energy of P diffusion in a Si crystal, which is considered as a summation of formation energy and migration barrier energy, leading to the enhancement of diffusion of P atoms at low temperatures, which has been suggested by recent experimental studies.

  13. Enhancing soluble phosphorus removal within buffer strips using industrial by-products.

    Science.gov (United States)

    Habibiandehkordi, Reza; Quinton, John N; Surridge, Ben W J

    2014-11-01

    Using industrial by-products (IBPs) in conjunction with buffer strips provides a potentially new strategy for enhancing soluble phosphorus (P) removal from agricultural runoff. Here, we investigate the feasibility of this approach by assessing the P sorption properties of IBPs at different solution-IBPs contact time (1-120 min) and solution pH (3, 5.5, 7.5), as well as possible adverse environmental effects including P desorption or heavy metal mobilisation from IBPs. Batch experiments were carried out on two widely available IBPs in the UK that demonstrated high P sorption capacity but different physicochemical characteristics, specifically ochre and Aluminium (Al) based water treatment residuals (Al-WTR). A series of kinetic sorption-desorption experiments alongside kinetic modelling were used to understand the rate and the mechanisms of P removal across a range of reaction times. The results of the kinetic experiments indicated that P was initially sorbed rapidly to both ochre and Al-WTR, followed by a second phase characterised by a slower sorption rate. The excellent fits of kinetic sorption data to a pseudo-second order model for both materials suggested surface chemisorption as the rate-controlling mechanism. Neither ochre nor Al-WTR released substantial quantities of either P or heavy metals into solution, suggesting that they could be applied to buffer strip soils at recommended rates (≤30 g kg(-1) soil) without adverse environmental impact. Although the rate of P sorption by freshly-generated Al-WTR applied to buffer strips reduced following air-drying, this would not limit its practical application to buffer strips in the field if adequate contact time with runoff was provided. PMID:24928382

  14. Startup and long term operation of enhanced biological phosphorus removal in continuous-flow reactor with granules.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-07-01

    The startup and long term operation of enhanced biological phosphorus removal (EBPR) in a continuous-flow reactor (CFR) with granules were investigated in this study. Through reducing the settling time from 9min to 3min gradually, the startup of EBPR in a CFR with granules was successfully realized in 16days. Under continuous-flow operation, the granules with good phosphorus and COD removal performance were stably operated for more than 6months. And the granules were characterized with particle size of around 960μm, loose structure and good settling ability. During the startup phase, polysaccharides (PS) was secreted excessively by microorganisms to resist the influence from the variation of operational mode. Results of relative quantitative PCR indicated that granules dominated by polyphosphate-accumulating organisms (PAOs) were easier accumulated in the CFR because more excellent settling ability was needed in the system. PMID:27085149

  15. Long term operation of continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-09-01

    In this study, a continuous-flow system with enhanced biological phosphorus removal (EBPR) granules was operated at different COD concentrations (200, 300 and 400mgL(-)(1)) to investigate the effect of COD loading on this system. The results showed that when the COD concentration in influent was increased to 400mgL(-)(1), the anaerobic COD removal efficiency and total phosphorus removal efficiency reduced obviously and the settling ability of granules deteriorated due to the proliferation of filamentous bacteria. Moreover, high COD loading inhibited the EPS secretion and destroyed the stability of granules. Results of high-through pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading. The performance of system, settling ability of granules and proportion of PAOs gradually recovered to the initial level after the COD concentration was reduced to 200mgL(-)(1) on day 81. PMID:27295254

  16. Population dynamics in wastewater treatment plants with enhanced biological phosphorus removal operated with and without nitrogen removal

    DEFF Research Database (Denmark)

    Lee, N.; Jansen, J.l.C.; Aspegren, H.;

    2002-01-01

    to the pilot plant was periodically manipulated by external addition of phosphorus (P), acetate and glucose, respectively. The population dynamics and the in situ physiology were monitored by quantitative fluorescence in situ hybridization (FISH) and microautoradiography. Significant P removal was observed......The population dynamics of activated sludge in a pilot plant with two activated sludge systems, both designed for enhanced biological phosphorus removal (EBPR), but one of them with (BNP) and the other without (BP) nitrogen removal, was monitored during a period of 2.5 years. The influent water...... Proteobacteria (part of them Rhodocyclus-related, the identity of the rest unknown) and the Actinobacteria. However, not all of the Rhodocyclus-related bacteria showed 33Pi uptake. The P removal in the investigated plants is thus believed to be mediated by a mixed population consisting of a part...

  17. Enhanced coagulation of ferric chloride aided by tannic acid for phosphorus removal from wastewater.

    Science.gov (United States)

    Zhou, Yunan; Xing, Xin-Hui; Liu, Zehua; Cui, Liwen; Yu, Anfeng; Feng, Quan; Yang, Haijun

    2008-05-01

    Phosphorus removal from wastewater is of great importance. In the present study, ferric chloride was selected as the coagulant, and tannic acid (TA), a natural polymer, as the coagulant aid to develop an effective coagulation process with the emphasis of phosphorus recovery from different types of wastewater. The results showed that TA can accelerate the settling speed by forming flocs with large size, reduce the residual Fe(III) to eliminate the yellow color caused by Fe(III), and slightly increase the phosphorus removal efficiency. The precipitate formed by TA-aided coagulation showed the advantage of releasing phosphorus faster than ferric phosphate, indicating the possibility of phosphorus recovery from wastewater as slow release fertilizer. To further understand the structural characteristics of the precipitate, analytical techniques such as Raman spectroscopy, X-ray photoelectron spectroscopy and matrix-assisted laser desorption ionization-time of flight mass spectrometry were employed. The analytical results indicated that TA-Fe-P complex was formed during the coagulation/flocculation processes. Solid phase in the precipitate consisted of TA-Fe-P complex, Fe-TA complex and/or ferric hydroxyphosphate. PMID:18395769

  18. "Candidatus Propionivibrio aalborgensis": A Novel Glycogen Accumulating Organism Abundant in Full-Scale Enhanced Biological Phosphorus Removal Plants.

    Science.gov (United States)

    Albertsen, Mads; McIlroy, Simon J; Stokholm-Bjerregaard, Mikkel; Karst, Søren M; Nielsen, Per H

    2016-01-01

    Enhanced biological phosphorus removal (EBPR) is widely used to remove phosphorus from wastewater. The process relies on polyphosphate accumulating organisms (PAOs) that are able to take up phosphorus in excess of what is needed for growth, whereby phosphorus can be removed from the wastewater by wasting the biomass. However, glycogen accumulating organisms (GAOs) may reduce the EBPR efficiency as they compete for substrates with PAOs, but do not store excessive amounts of polyphosphate. PAOs and GAOs are thought to be phylogenetically unrelated, with the model PAO being the betaproteobacterial "Candidatus Accumulibacter phosphatis" (Accumulibacter) and the model GAO being the gammaproteobacterial "Candidatus Competibacter phosphatis". Here, we report the discovery of a GAO from the genus Propionivibrio, which is closely related to Accumulibacter. Propionivibrio sp. are targeted by the canonical fluorescence in situ hybridization probes used to target Accumulibacter (PAOmix), but do not store excessive amounts of polyphosphate in situ. A laboratory scale reactor, operated to enrich for PAOs, surprisingly contained co-dominant populations of Propionivibrio and Accumulibacter. Metagenomic sequencing of multiple time-points enabled recovery of near complete population genomes from both genera. Annotation of the Propionivibrio genome confirmed their potential for the GAO phenotype and a basic metabolic model is proposed for their metabolism in the EBPR environment. Using newly designed fluorescence in situ hybridization (FISH) probes, analyses of full-scale EBPR plants revealed that Propionivibrio is a common member of the community, constituting up to 3% of the biovolume. To avoid overestimation of Accumulibacter abundance in situ, we recommend the use of the FISH probe PAO651 instead of the commonly applied PAOmix probe set. PMID:27458436

  19. “Candidatus Propionivibrio aalborgensis”: A Novel Glycogen Accumulating Organism Abundant in Full-Scale Enhanced Biological Phosphorus Removal Plants

    Science.gov (United States)

    Albertsen, Mads; McIlroy, Simon J.; Stokholm-Bjerregaard, Mikkel; Karst, Søren M.; Nielsen, Per H.

    2016-01-01

    Enhanced biological phosphorus removal (EBPR) is widely used to remove phosphorus from wastewater. The process relies on polyphosphate accumulating organisms (PAOs) that are able to take up phosphorus in excess of what is needed for growth, whereby phosphorus can be removed from the wastewater by wasting the biomass. However, glycogen accumulating organisms (GAOs) may reduce the EBPR efficiency as they compete for substrates with PAOs, but do not store excessive amounts of polyphosphate. PAOs and GAOs are thought to be phylogenetically unrelated, with the model PAO being the betaproteobacterial “Candidatus Accumulibacter phosphatis” (Accumulibacter) and the model GAO being the gammaproteobacterial “Candidatus Competibacter phosphatis”. Here, we report the discovery of a GAO from the genus Propionivibrio, which is closely related to Accumulibacter. Propionivibrio sp. are targeted by the canonical fluorescence in situ hybridization probes used to target Accumulibacter (PAOmix), but do not store excessive amounts of polyphosphate in situ. A laboratory scale reactor, operated to enrich for PAOs, surprisingly contained co-dominant populations of Propionivibrio and Accumulibacter. Metagenomic sequencing of multiple time-points enabled recovery of near complete population genomes from both genera. Annotation of the Propionivibrio genome confirmed their potential for the GAO phenotype and a basic metabolic model is proposed for their metabolism in the EBPR environment. Using newly designed fluorescence in situ hybridization (FISH) probes, analyses of full-scale EBPR plants revealed that Propionivibrio is a common member of the community, constituting up to 3% of the biovolume. To avoid overestimation of Accumulibacter abundance in situ, we recommend the use of the FISH probe PAO651 instead of the commonly applied PAOmix probe set. PMID:27458436

  20. BIOLOGY OF POLYPHOSPHATE-ACCUMULATING BACTERIA INVOLVED IN ENHANCED BIOLOGICAL PHOSPHORUS REMOVAL

    NARCIS (Netherlands)

    KORTSTEE, GJJ; APPELDOORN, KJ; BONTING, CFC; VANNIEL, EWJ; VANVEEN, HW

    1994-01-01

    Recent research on the process of biological phosphorus removal in lab-scale treatment systems has indicated that: (i) the development of an actively polyP-accumulating bacterial community after the introduction of an anaerobic period may take at least 4 months; (ii) up to 80% of all aerobic bacteri

  1. Controlled biomass removal - the key parameter to achieve enhanced biological phosphorus removal in biofilm systems

    DEFF Research Database (Denmark)

    Morgenroth, E.

    1999-01-01

    ) had only a minor effect on overall phosphorus removal. Soluble components fully penetrate the biofilm at certain times during the SBBR cycle as a consequence of SBBR operation with large concentration variations over the cycle time. The limiting processes for EBPR is the efficient removal...... and intensive backwashing resulting in thin biofilms is suggested. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved....

  2. Enhanced electro-oxidation resistance of carbon electrodes induced by phosphorus surface groups

    OpenAIRE

    Berenguer Betrián, Raúl; Ruiz Rosas, Ramiro; Gallardo, Aurora; Cazorla Amorós, Diego; Morallón Núñez, Emilia; Nishihara, Hirotomo; Kyotani, Takashi; Rodríguez-Mirasol, José; Cordero, Tomás

    2015-01-01

    The electro-oxidation of carbon materials enormously degrades their performance and limits their wider utilization in multiple electrochemical applications. In this work, the positive influence of phosphorus functionalities on the overall electrochemical stability of carbon materials has been demonstrated under different conditions. We show that the extent and selectivity of electroxidation in P-containing carbons are completely different to those observed in conventional carbons without P. T...

  3. Arbuscular mycorrhizal fungal colonization of Glycyrrhiza glabra roots enhances plant biomass, phosphorus uptake and concentration of root secondary metabolites

    Institute of Scientific and Technical Information of China (English)

    HongLing LIU; Yong TAN; Monika NELL; Karin ZITTER-EGLSEER; Chris WAWSCRAH; Brigitte KOPP; ShaoMing WANG; Johannes NOVAK

    2014-01-01

    Arbuscular mycorrhizal (AM) fungi penetrate the cortical cells of the roots of vascular plants, and are widely distributed in soil. The formation of these symbiotic bodies accelerates the absorption and utilization of min-eral elements, enhances plant resistance to stress, boosts the growth of plants, and increases the survival rate of transplanted seedlings. We studied the effects of various arbuscular mycorrhizae fungi on the growth and devel-opment of licorice (Glycyrrhiza glabra). Several species of AM, such as Glomus mosseae, Glomus intraradices, and a mixture of fungi (G. mosseae, G. intraradices, G. cladoideum, G. microagregatum, G. caledonium and G. etunica-tum) were used in our study. Licorice growth rates were determined by measuring the colonization rate of the plants by the fungi, plant dry biomass, phosphorus concentration and concentration of secondary metabolites. We estab-lished two cloned strains of licorice, clone 3 (C3) and clone 6 (C6) to exclude the effect of genotypic variations. Our results showed that the AM fungi could in fact increase the leaf and root biomass, as well as the phosphorus con-centration in each clone. Furthermore, AM fungi significantly increased the yield of certain secondary metabolites in clone 3. Our study clearly demonstrated that AM fungi play an important role in the enhancement of growth and development of licorice plants. There was also a significant improvement in the secondary metabolite content and yield of medicinal compounds from the roots.

  4. Ectopic Expression of a Phytase Gene from Medicago truncatula Barrel Medic Enhances Phosphorus Absorption in Plants

    Institute of Scientific and Technical Information of China (English)

    Kai Xiao; Jian-Heng Zhang; Maria Harrison; Zeng-Yu Wang

    2006-01-01

    In the present study, the phosphorus-absorption capacity of transgenic Arabidopsis plants ectopically expressing a novel phytase gene from Medicago truncatula Barrel Medic was evaluated. A full-length cDNA encoding an extracellular form of phytase was isolated from the model legume M. truncatula. The phytase gene (MtPHY1) has an open reading frame of 1 632 bp predicted to encode 543 amino acids, including an Nterminal signal peptide of 27 amino acids. The genomic sequence of the MtPHY1 gene is 5 151 bp, containing seven exons interrupted by six introns. Under high-Pi (2 mmol/L) growth conditions, higher levels of MtPHY1transcripts accumulated in the leaf and stem than in the root. The transcript level was reduced in the stem and increased in the root, with no obvious changes in the hybridization signal detected in the leaf under lowPi (10 μmol/L) conditions. Chimeric transgenes were constructed by placing MtPHY1 under the control of the constitutive CaMV35S promoter and the root-specific MtPT1 promoter. Phytase activities in root apoplast of transgenic Arabidopsis were 12.3- to 16.2-fold of that in control plants. The phytase expressed was secreted into the rhizosphere, as demonstrated by HPLC analysis of phytate degradation by root exudates. Ectopic expression of MtPHY1 in Arabidopsis, leading to significant improvement in organic phosphorus absorption and plant growth, indicated that MtPHY1 has great potential for improving plant phosphorus absorption and phytoremediation.

  5. Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.

    Science.gov (United States)

    Lin, Tzu-Yu; Wei, Chia-Cheng; Huang, Chi-Wei; Chang, Chun-Han; Hsu, Fu-Lan; Liao, Vivian Hsiu-Chuan

    2016-03-23

    Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater.

  6. Effect of high calcium concentration influents on enhanced biological phosphorus removal process

    International Nuclear Information System (INIS)

    In this work, the effect of calcium concentration in wastewater on the polyphosphate accumulating organisms (PAO) is investigated as well as its influence in PAO metabolism, specifically in the YPO4 (ratio between phosphorus release and acetic acid uptake). For this study a sequencing batch reactor (SBR) anaerobic-aerobic was used, in which the PAO enriched biomass was exposed to different calcium concentrations in the influent wastewater. The results indicate that until a given calcium level in the influent wastewater (35 mg Ca/l) the metabolism is not affect, but higher calcium concentrations lead to significant YPO4 decline. (Author) 18 refs.

  7. Enhancing effect of induced crystallization process on denitrifying phosphorus removal%诱导结晶对反硝化除磷的强化作用

    Institute of Scientific and Technical Information of China (English)

    顾倩; 吕锡武; 史静; 李洁

    2013-01-01

    To investigate the enhancing effect of induced crystallization on the denitrifying phosphorus removal,experiments were carried out by combining the two-sludge system and the induced crystallization process.The results show that the phosphorus recovery rate of induced crystallizer is not greatly improved when the mole ratio of n(Ca2+)/n(PO43--P) reaches 5∶1.The optimum value of n (Ca2 +)/n (PO43--P) is 3∶1 which achieves a phosphorus recovery rate of 62.05 %.Appropriately increasing the amount of phosphorus recovery does not have a significant effect on the amount of anaerobic phosphorus release.When the amount of phosphorus release maintains at (13.44 ± 0.55)mg/L,the amount of phosphorus uptake decreases from 21.11 to 16.42 mg/L.The ratio of phosphorus uptake amount to release amount falls from 1.51 to 1.24 along with a high recovery rate,which means that the burden of bio-P removal is lightened.During the prior period of denitrifying phosphorus removal,the rate of phosphorus uptake goes down while the amount of phosphorus recovery increases,but the reaction of denitrifying phosphorus removal all ends after 30 min.Chemical phosphorus recovery do not cause negative effect on biological phosphorus removal.Moreover,the process which combines biological phosphorus removal with chemical phosphorus recovery can ensure that the effluent quality meets the related requirements under the condition of low influent CODto-phosphorus mass ratio.%以双污泥-诱导结晶工艺为研究对象,考察诱导结晶工艺回收磷对反硝化除磷的强化作用.结果表明,当摩尔比n(Ca2+)/n(PO43--P)提高到5∶1时,反应器内回收率没有明显的提高,最佳n(Ca2+)/n(PO43--P)为3∶1,回收率可达62.05%;提高磷回收量对厌氧释磷影响并不大,当释磷量保持在(13.44±0.55) mg/L时,聚磷量由21.11 mg/L降至16.42 mg/L,聚磷量与释磷量之比从1.51降至1.24,化学回收磷减轻了生物除磷负担;提高结晶磷回收量会降低聚磷

  8. Enhanced nitrogen and phosphorus removal from eutrophic lake water by Ipomoea aquatica with low-energy ion implantation.

    Science.gov (United States)

    Li, Miao; Wu, Yue-Jin; Yu, Zeng-Liang; Sheng, Guo-Ping; Yu, Han-Qing

    2009-03-01

    Ipomoea aquatica with low-energy N+ ion implantation was used for the removal of both nitrogen and phosphorus from the eutrophic Chaohu Lake, China. The biomass growth, nitrate reductase and peroxidase activities of the implanted I. aquatica were found to be higher than those of I. aquatica without ion implantation. Higher NO3-N and PO4-P removal efficiencies were obtained for the I. aquatica irradiation at 25 keV, 3.9 x 10(16) N+ ions/cm(2) and 20 keV 5.2 x 10(16) N+ ions/cm(2), respectively (p phosphorus contents in the plant biomass with ion implantation were also greater than those of the controls. I. aquatica with ion implantation was directly responsible for 51-68% N removal and 54-71% P removal in the three experiments. The results further confirm that the ion implantation could enhance the growth potential of I. aquatica in real eutrophic water and increase its nutrient removal efficiency. Thus, the low-energy ion implantation for aquatic plants could be considered as an approach for in situ phytoremediation and bioremediation of eutrophic waters.

  9. Phosphorus-Doped Carbon Nitride Tubes with a Layered Micro-nanostructure for Enhanced Visible-Light Photocatalytic Hydrogen Evolution.

    Science.gov (United States)

    Guo, Shien; Deng, Zhaopeng; Li, Mingxia; Jiang, Baojiang; Tian, Chungui; Pan, Qingjiang; Fu, Honggang

    2016-01-26

    Phosphorus-doped hexagonal tubular carbon nitride (P-TCN) with the layered stacking structure was obtained from a hexagonal rod-like single crystal supramolecular precursor (monoclinic, C2/m). The production process of P-TCN involves two steps: 1) the precursor was prepared by self-assembly of melamine with cyanuric acid from in situ hydrolysis of melamine under phosphorous acid-assisted hydrothermal conditions; 2) the pyrolysis was initiated at the center of precursor under heating, thus giving the hexagonal P-TCN. The tubular structure favors the enhancement of light scattering and active sites. Meanwhile, the introduction of phosphorus leads to a narrow band gap and increased electric conductivity. Thus, the P-TCN exhibited a high hydrogen evolution rate of 67 μmol h(-1) (0.1 g catalyst, λ >420 nm) in the presence of sacrificial agents, and an apparent quantum efficiency of 5.68 % at 420 nm, which is better than most of bulk g-C3 N4 reported.

  10. Enhanced phosphorus removal in the DAF process by flotation scum recycling for advanced treatment of municipal wastewater.

    Science.gov (United States)

    Kwak, Dong-Heui; Lee, Ki-Cheol

    2015-01-01

    To remove phosphorus (P) from municipal wastewater, various types of advanced treatment processes are being actively applied. However, there is commonly a space limit in municipal wastewater treatment plants (MWTPs). For that reason, the dissolved air flotation (DAF), which is well known for small space and flexible application process, is preferred as an additive process to enhance the removal of P. A series of experiments were conducted to investigate the feasibility of flotation scum recycling for effective P removal from a MWTP using a DAF pilot plant over 1 year. The average increases in the removal efficiencies due to flotation scum recycling were 22.6% for total phosphorus (T-P) and 18.3% for PO4-P. A higher removal efficiency of T-P was induced by recycling the flotation scum because a significant amount of Al components remained in the flotation scum. The increase in T-P removal efficiency, due to the recycling of flotation scum, shifted from the boundary of the stoichiometric precipitate to the equilibrium control region. Flotation scum recycling may contribute to improving the quality of treated water and reducing treatment costs by minimizing the coagulant dosage required.

  11. Phosphorus-Doped Carbon Nitride Tubes with a Layered Micro-nanostructure for Enhanced Visible-Light Photocatalytic Hydrogen Evolution.

    Science.gov (United States)

    Guo, Shien; Deng, Zhaopeng; Li, Mingxia; Jiang, Baojiang; Tian, Chungui; Pan, Qingjiang; Fu, Honggang

    2016-01-26

    Phosphorus-doped hexagonal tubular carbon nitride (P-TCN) with the layered stacking structure was obtained from a hexagonal rod-like single crystal supramolecular precursor (monoclinic, C2/m). The production process of P-TCN involves two steps: 1) the precursor was prepared by self-assembly of melamine with cyanuric acid from in situ hydrolysis of melamine under phosphorous acid-assisted hydrothermal conditions; 2) the pyrolysis was initiated at the center of precursor under heating, thus giving the hexagonal P-TCN. The tubular structure favors the enhancement of light scattering and active sites. Meanwhile, the introduction of phosphorus leads to a narrow band gap and increased electric conductivity. Thus, the P-TCN exhibited a high hydrogen evolution rate of 67 μmol h(-1) (0.1 g catalyst, λ >420 nm) in the presence of sacrificial agents, and an apparent quantum efficiency of 5.68 % at 420 nm, which is better than most of bulk g-C3 N4 reported. PMID:26692105

  12. Assessment of crude glycerol for Enhanced Biological Phosphorus Removal: Stability and role of long chain fatty acids.

    Science.gov (United States)

    Tayà, Carlota; Guerrero, Javier; Suárez-Ojeda, María Eugenia; Guisasola, Albert; Baeza, Juan Antonio

    2015-12-01

    Enhanced Biological Phosphorus Removal (EBPR) of urban wastewaters is usually limited by the available carbon source required by Polyphosphate Accumulating Organisms (PAO). External carbon sources as volatile fatty acids (VFA) or other pure organic compounds have been tested at lab scale demonstrating its ability to enhance PAO activity, but the application of this strategy at full-scale WWTPs is not cost-effective. The utilization of industrial by-products with some of these organic compounds provides lower cost, but it has the possible drawback of having inhibitory or toxic compounds to PAO. This study is focused on the utilization of crude glycerol, the industrial by-product generated in the biodiesel production, as a possible carbon source to enhance EBPR in carbon-limited urban wastewaters. Crude glycerol has non-negligible content of other organic compounds as methanol, salts, VFA and long chain fatty acids (LCFA). VFA and methanol have been demonstrated to enhance PAO activity, but there is no previous study about the effect of LCFA on PAO. This work presents the operation of an EBPR SBR system using crude glycerol as sole carbon source, studying also its long-term stability. The effect of LCFA is evaluated at short and long-term operation, demonstrating for the first time EBPR activity with LCFA as sole carbon source and its long-term failure due to the increased hydrophobicity of the sludge. PMID:26092200

  13. The effect of COD loading on the granule-based enhanced biological phosphorus removal system and the recoverability.

    Science.gov (United States)

    Yu, Shenjing; Sun, Peide; Zheng, Wei; Chen, Lujun; Zheng, Xiongliu; Han, Jingyi; Yan, Tao

    2014-11-01

    In this study, the effect of varied COD loading (200, 400, 500, 600 and 800 mg L(-1)) on stability and recoverability of granule-based enhanced biological phosphorus removal (EBPR) system was investigated during continuously 53-d operation. Results showed that COD loading higher than 500 mg L(-1) could obviously deteriorate the granular EBPR system and result in sludge bulking with filamentous bacteria. High COD loading also changed the transformation patterns of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process of polyphosphate-accumulating organisms (PAOs) and inhibited the EPS secretion, which completely destroyed the stability and integrality of granules. Results of FISH indicated that glycogen-accumulating organisms (GAOs) and other microorganisms had a competitive advantage over PAOs with higher COD loading. The community composition and EBPR performance were recovered irreversibly in long time operation when COD loading was higher than 500 mg L(-1). PMID:25189512

  14. Community proteogenomics highlights microbial strain-variant protein expression within activated sludge performing enhanced biological phosphorus removal.

    Energy Technology Data Exchange (ETDEWEB)

    Wilmes, P [University of California, Berkeley; Andersson, Anders F. [University of California, Berkeley; Lefsrud, Mark G [McGill University, Montreal, Quebec; Wexler, Margaret [University of East Anglia, Norwich, United Kingdom; Shah, Manesh B [ORNL; Zhang, B [Vanderbilt University; Hettich, Robert {Bob} L [ORNL; Bond, P. L. [University of Queensland, The, Brisbane, Queensland, Australia; Verberkmoes, Nathan C [ORNL; Banfield, Jillian F. [University of California, Berkeley

    2008-01-01

    Enhanced biological phosphorus removal (EBPR) selects for polyphosphate accumulating organisms to achieve phosphate removal from wastewater. We used highresolution community proteomics to identify key metabolic pathways in "Candidatus Accumulibacter phosphatis"-mediated EBPR and to evaluate the contributions of co- 5 existing strains within the dominant population. Results highlight the importance of denitrification, fatty acid cycling and the glyoxylate bypass in EBPR. Despite overall strong similarity in protein profiles under anaerobic and aerobic conditions, fatty acid degradation proteins were more abundant during the anaerobic phase. By comprehensive genome-wide alignment of orthologous proteins, we uncovered strong 10 functional partitioning for enzyme variants involved in both core-metabolism and EBPR-specific pathways among the dominant strains. These findings emphasize the importance of genetic diversity in maintaining the stable performance of EBPR systems and demonstrate the power of integrated cultivation-independent genomics and proteomics for analysis of complex biotechnological systems.

  15. Effect of sludge retention time on continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-11-01

    The effect of sludge retention time (SRT) on the continuous-flow system with enhanced biological phosphorus removal (EBPR) granules at different COD loading was investigated during the operation of more than 220days. And the results showed that when the system operated at long SRT (30days) and low COD loading (200mg·L(-1)), it could maintain excellent performance. However, long SRT and high COD loading (300mg·L(-1)) deteriorated the settling ability of granules and the performance of system and resulted in the overgrowth of filamentous bacteria. Meanwhile, the transformation of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process was inhibited. Moreover, the results of pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading and long SRT. The PAOs specious of Candidatus_Accumlibater and system performance increased obviously when the SRT was reduced to 20days at high COD loading. PMID:27472749

  16. The potential role of 'Candidatus Microthrix parvicella' in phosphorus removal during sludge bulking in two full-scale enhanced biological phosphorus removal plants.

    Science.gov (United States)

    Wang, Juan; Qi, Rong; Liu, Miaomiao; Li, Qian; Bao, Haipeng; Li, Yaming; Wang, Shen; Tandoi, Valter; Yang, Min

    2014-01-01

    We investigated the bacterial community compositions and phosphorus removal performance under sludge bulking and non-bulking conditions in two biological wastewater treatment systems (conventional A²/O (anaerobic/anoxic/aerobic) and inverted A²/O (anoxic/anaerobic/aerobic) processes) receiving the same raw wastewater. Sludge bulking resulted in significant shift in bacterial compositions from Proteobacteria dominance to Actinobacteria dominance, characterized by the significant presence of filamentous 'Candidatus Microthrix parvicella'. Quantitative real-time polymerase chain reaction (PCR) analysis revealed that the relative abundance of 'Candidatus Accumulibacter phosphatis', a key polyphosphate-accumulating organism responsible for phosphorus removal, with respect to 16s rRNA genes of total bacteria was 0.8 and 0.7%, respectively, for the conventional and inverted A²/O systems when sludge bulking occurred, which increased to 8.2 and 12.3% during the non-bulking period. However, the total phosphorus removal performance during the bulking period (2-week average: 97 ± 1 and 96 ± 1%, respectively) was not adversely affected comparable to that during the non-bulking period (2-week average: 96 ± 1 and 96 ± 1%, respectively). Neisser staining revealed the presence of large polyphosphate granules in 'Candidatus Microthrix parvicella', suggesting that this microbial group might have been responsible for phosphorus removal during the sludge bulking period when 'Candidatus Accumulibacter phosphatis' was excluded from the systems. PMID:25051486

  17. A metabolic model for members of the genus Tetrasphaera involved in enhanced biological phosphorus removal

    DEFF Research Database (Denmark)

    Kristiansen, Rikke; Nguyen, Hien Thi Thu; Saunders, Aaron Marc;

    2013-01-01

    and substrate fermentation. During the aerobic phase, the stored glycogen is catabolized to provide energy for growth and to replenish the intracellular polyphosphate reserves needed for subsequent anaerobic metabolism. They are also able to denitrify. This physiology is markedly different to that displayed...... Accumulibacter phosphatis’ is unclear, although they may occupy different ecological niches in EBPR communities. The genomes of four Tetrasphaera isolates (T. australiensis, T. japonica, T. elongata and T. jenkinsii) were sequenced and annotated, and the data used to construct metabolic models. These models...... incorporate central aspects of carbon and phosphorus metabolism critical to understanding their behavior under the alternating anaerobic/aerobic conditions encountered in EBPR systems. Key features of these metabolic pathways were investigated in pure cultures, although poor growth limited their analyses to T...

  18. Phosphorus application to cotton enhances growth, yield, and quality characteristics on a sandy loam soil

    International Nuclear Information System (INIS)

    Phosphorus (P) is the second most limiting nutrient in cotton (Gossypium hirsutum L.) production after nitrogen. Under wheat-cotton cropping system of Pakistan most of the farmers apply P fertilizer only to wheat crop. A field experiment was conducted to evaluate the effect of fertilizer P on the growth, yield and fibre quality of cotton on a sandy loam calcareous soil at farmer's field in cotton growing area of district Khanewal, Punjab. Five levels of P (0, 17, 26, 34 and 43 kg P ha /sup -1/) along with 120 kg N and 53 kg K ha/sup -1/ were applied. The response of cotton growth parameters was greater than quality components to P addition in calcareous soil. There was significant increase in the growth and yield parameters with each additional rate of P. The response of number of bolls per plant, boll weight and seed cotton yield was to the tune of 88.23, 16.82 and 42%, respectively at P application rate of 34 kg ha/sup -1/. Cotton quality components (lint %age, fiber length and fiber strength) improved from 2 to 5% where 43 kg P ha/sup -1/ was added. The lint and seed P concentration was little affected by P application as compared to stem and leaves showing its essentiality for cell division and development of meristematic tissue. Phosphorus use, thus not only valuable for wheat crop but also its application to cotton crop is of vital importance in improving both lint yield and quality. (author)

  19. 强化混凝除磷技术的研究进展%Research Progress of Phosphorus Removal in Enhanced Coagulation

    Institute of Scientific and Technical Information of China (English)

    唐朝春; 邵鹏辉; 简美鹏; 余荷根

    2013-01-01

    Phosphorus is one of the prime cause of eutrophication,the research of phosphorus removal technology catched the most attention all the time.The traditional chemical aluminous salt,ferric salt coagulants for phosphorus removal and flocculation reactor's features were analyzed,which was focused on introducing the application and the progress of the solutions for the phosphorus removal,such as new type of coagulant,new coagulation craft and new flocculation reactor.It pointed out the core issues in restricting the development of the methods of enhanced coagulation in phosphorus removal,and gived a clear direction for the research of the methods of enhanced coagulation in phosphorus removal.The enhanced coagulation technology at lower cost and less energy was worth deeply researching.%磷是造成水体富营养化的主要原因之一,除磷技术的研究倍受人们关注.分析了传统化学除磷铝盐、铁盐混凝剂及其絮凝反应器的特性,介绍了新型混凝剂、新型混凝工艺及新型絮凝反应器等强化混凝技术在除磷方面最新的应用与研究进展,并对限制强化混凝除磷技术突破性进展的关键性问题及未来主要研究方向进行了探析,提出了高效低耗强化混凝除磷技术值得进一步研究的思路.

  20. Analysis of poly-β-hydroxyalkonates (PHA) during the enhanced biological phosphorus removal process using FTIR spectroscopy.

    Science.gov (United States)

    Li, Wei-hua; Mao, Qin-yan; Liu, Yi-xin; Sheng, Guo-ping; Yu, Han-qing; Huang, Xian-huai; Liu, Shao-geng; Ling, Qi; Yan, Guo-bing

    2014-06-01

    Enhanced biological phosphorus removal (EBPR) is the main phosphorus removal technique for wastewater treatment. During the anaerobic-aerobic alternative process, the activated sludge experienced the anaerobic storage of polyhydroxy-β-alkonates (PHA) and aerobic degradation, corresponding the infrared peak intensity of sludge at 1 740 cm(-1) increased in the aerobic phase and declined in the anaerobic phase. Compared with PHA standard, this peak was indentified to attribute the carbonyl of PHA. The overlapping peaks of PHA, protein I and II bands were separated using Gaussian peak fitting method. The infrared peak area ratios of PHA versus protein I had a good relationship with the PHA contents measured by gas chromatography, and the correlation coefficient was 0.873. Thus, the ratio of the peak area of PHA versus protein I can be considered as the indicator of the PHA content in the sludge. The infrared spectra of 1 480-1 780 cm(-1) was selected, normalized and transferred to the absorption data. Combined with the chromatography analysis of PHA content in the sludge sample, a model between the Fourier-transform infrared spectroscopy (ETIR) spectra of the sludge and PHA content was established, which could be used for the prediction of the PHA content in the unknown sample. The PHA content in the sludge sample could be acquired by the infrared spectra of the sludge sample and the established model, and the values fitted well with the results obtained from chromatograph. The results would provide a novel analysis method for the rapid characterization and quantitative determination of the intracellular PHA content in the activated sludge. PMID:25358156

  1. Phosphorus Recovery from Sewage Sludge Ash via Microwave Enhanced Thermochemical Treatment

    OpenAIRE

    Šyc, M. (Michal); Kameníková, P. (Petra); Giray, E.; Sobek, J; Pohořelý, M. (Michael); Svoboda, K.; Punčochář, M.

    2014-01-01

    Results of preliminary tests of sewage sludge ash (SSA) thermochemical treatment by means of chlorination agent with microwave enhanced heating are presented in the study. Elements speciation obtained by BCR sequential extraction procedure was studied in raw and treated SSA. Comparison of conventional and microwave enhanced heating at the same temperature on removal efficiency is presented as well.

  2. Manure and nitrogen application enhances soil phosphorus mobility in calcareous soil in greenhouses.

    Science.gov (United States)

    Yan, Zhengjuan; Chen, Shuo; Li, Junliang; Alva, Ashok; Chen, Qing

    2016-10-01

    Over many years, high phosphorus (P) loading for intensive vegetable cropping in greenhouses of North China has contributed to excessive P accumulation, resulting in environmental risk. In this study, the influences of manure and nitrogen (N) application on the transformation and transport of soil P were investigated after nine years in a greenhouse tomato double cropping system (winter-spring and autumn-winter seasons). High loading of manure significantly increased the soil inorganic P (Pi), inositol hexakisphosphate (IHP), mobile P and P saturation ratio (PSR, >0.7 in 0-30 cm depth soil; PSR was estimated from P/(Fe + Al) in an oxalate extract of the soil). The high rate of N fertilizer application to the studied calcareous soil with heavy loading of manure increased the following: (i) mobile organic P (Po) and Pi fractions, as evidenced by the decrease in the ratio of monoesters to diesters and the proportion of stable Pi (i.e., HCl-Pi) in total P (Pt) in 0-30 cm depth soil; (ii) relative distribution of Po in the subsoil layer; and (iii) P leaching to soil depths below 90 cm and the proportion of Po in Pt in the leachate. More acidic soil due to excessive N application increased P mobility and leaching. The increase in Ox-Al (oxalate-extractable Al) and the proportion of microbe-associated Po related to N application at soil depths of 0-30 cm suggested decrease in the net Po mineralization, which may contribute to downward transport of Po in the soil profile. PMID:27300290

  3. Anaerobic phosphate release from activated sludge with enhanced biological phosphorus removal. A possible mechanism of intracellular pH control

    Energy Technology Data Exchange (ETDEWEB)

    Bond, P.L.; Keller, J.; Blackall, L.L. [Univ. of Queensland, Brisbane (Australia)

    1999-06-05

    The biochemical mechanisms of the wastewater treatment process known as enhanced biological phosphorus removal (EBPR) are presently described in a metabolic model. The authors investigated details of the EBPR model to determine the nature of the anaerobic phosphate release and how this may be metabolically associated with polyhydroxyalkanoate (PHA) formation. Iodoacetate, an inhibitor of glycolysis, was found to inhibit the anaerobic formation of PHA and phosphate release, supporting the pathways proposed in the EBPR metabolic model. In the metabolic model, it is proposed that polyphosphate degradation provides energy for the microorganisms in anaerobic regions of these treatment systems. Other investigations have shown that anaerobic phosphate release depends on the extracellular pH. The authors observed that when the intracellular pH of EBPR sludge was raised, substantial anaerobic phosphate release was caused without volatile fatty acid (VFA) uptake. Acidification of the sludge inhibited anaerobic phosphate release even in the presence of VFA. from these observations, the authors postulate that an additional possible role of anaerobic polyphosphate degradation in EBPR is for intracellular pH control. Intracellular pH control may be a metabolic feature of EBPR, not previously considered, that could have some use in the control and optimization of EBPR.

  4. Enhanced biological phosphorus removal - results of a full scale pilot plant; Erhoehte biologische Phosphatelimination - Betriebsergebnisse einer grosstechnischen Versuchsanlage

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, P. [Kassel Univ. (Gesamthochschule) (Germany). Fachbereich 14 - Siedlungswasserwirtschaft; Bendzuck, C. [Kassel Univ. (Gesamthochschule) (Germany). Fachbereich 14 - Siedlungswasserwirtschaft

    1996-01-01

    Within a research project one line of Kassel`s wastewater treatment plant has been rebuilt to a large scale pilot plant run with the MUCT process configuration. Different investigations with variation of inflow size, trend of inflow over time and wastewater temperature have been done. The relation between the efficiency of enhanced biological phosphorus removal (EBPR) and the hydraulic loading is shown in some examples. Over all, the EBPR increases with the wastewater temperature, with the available organic carbon in the inflow and with decreasing fluctuation in the trend of inflow over time. (orig.) [Deutsch] Im Rahmen eines Forschungsvorhabens wurde ein Teil der biologischen Stufe der Kasseler Klaeranlage zur erhoehten biologischen Phosphatelimination nach dem MUCT-Verfahren umgebaut. Es wurden Versuche bei konstanter und periodisch schwankender hydraulischer Belastung sowie bei unterschiedlichen Abwassertemperaturen durchgefuehrt. Untersucht wurde die Abhaengigkeit der biologischen Phosphatelimination von verschiedenen Belastungssituationen und die Phosphorumsaetze innerhalb der Belebung sowohl in zeitlicher als auch in oertlicher Abhaengigkeit. Die Wiederholung bestimmter Versuchsphasen bei verschiedenen Abwassertemperaturen liess Rueckschluesse auf die Temperaturabhaengigkeit der biologischen Phosphatelimination zu. Der Wirkungsgrad der biologischen Phosphatelimination steigt mit der Temperatur, dem Angebot an organischem Kohlenstoff in der anaeroben Zone und mit zunehmender Vergleichmaessigung der hydraulischen Belastung. (orig.)

  5. Enhancing the Mobilization of Native Phosphorus in the Mung Bean Rhizosphere Using ZnO Nanoparticles Synthesized by Soil Fungi.

    Science.gov (United States)

    Raliya, Ramesh; Tarafdar, Jagadish Chandra; Biswas, Pratim

    2016-04-27

    Phosphorus (P) is a limiting factor to plant growth and productivity in almost half of the world's arable soil, and its uptake in plants is often constrained because of its low solubility in the soil. To avoid repeated and large quantity application of rock phosphate as a P fertilizer and enhance the availability of native P acquisition by the plant root surface, in this study a biosynthesized ZnO nanoparticle was used. Zn acts as a cofactor for P-solubilizing enzymes such as phosphatase and phytase, and nano ZnO increased their activity between 84 and 108%. The level of resultant P uptake in mung bean increased by 10.8%. In addition, biosynthesized ZnO also improves plant phenology such as stem height, root volume, and biochemical indicators such as leaf protein and chlorophyll contents. In the rhizosphere, increased chlorophyll content and root volume attract microbial populations that maintain soil biological health. ICP-MS results showed ZnO nanoparticles were distributed in all plant parts, including seeds. However, the concentration of Zn was within the limit of the dietary recommendation. To the best of our knowledge, this is the first holistic study focusing on native P mobilization using ZnO nanoparticles in the life cycle of mung bean plants. PMID:27054413

  6. Ectomycorrhizal fungi enhance nitrogen and phosphorus nutrition of Nothofagus dombeyi under drought conditions by regulating assimilative enzyme activities.

    Science.gov (United States)

    Alvarez, Maricel; Huygens, Dries; Olivares, Erick; Saavedra, Isabel; Alberdi, Miren; Valenzuela, Eduardo

    2009-08-01

    Drought stress conditions (DC) reduce plant growth and nutrition, restraining the sustainable reestablishment of Nothofagus dombeyi in temperate south Chilean forest ecosystems. Ectomycorrhizal symbioses have been documented to enhance plant nitrogen (N) and phosphorus (P) uptake under drought, but the regulation of involved assimilative enzymes remains unclear. We studied 1-year-old N. dombeyi (Mirb.) Oerst. plants in association with the ectomycorrhizal fungi Pisolithus tinctorius (Pers.) Coker & Couch. and Descolea antartica Sing. In greenhouse experiments, shoot and root dry weights, mycorrhizal colonization, foliar N and P concentrations, and root enzyme activities [glutamate synthase (glutamine oxoglutarate aminotransferase (GOGAT), EC 1.4.1.13-14), glutamine synthetase (GS, EC 6.3.1.2), glutamate dehydrogenase (GDH, EC 1.4.1.2-4), nitrate reductase (NR, EC 1.6.6.1), and acid phosphomonoesterase (PME, EC 3.1.3.1-2)] were determined as a function of soil-water content. Inoculation of N. dombeyi with P. tinctorius and D. antartica significantly stimulated plant growth and increased plant foliar N and P concentrations, especially under DC. Ectomycorrhizal inoculation increased the activity of all studied enzymes relative to non-mycorrhizal plants under drought. We speculate that GDH is a key enzyme involved in the enhancement of ectomycorrhizal carbon (C) availability by fuelling the tricarboxylic acid (TCA) cycle under conditions of drought-induced carbon deficit. All studied assimilative enzymes of the ectomycorrhizal associations, involved in C, N, and P transfers, are closely interlinked and interdependent. The up-regulation of assimilative enzyme activities by ectomycorrhizal fungal root colonizers acts as a functional mechanism to increase seedling endurance to drought. We insist upon incorporating ectomycorrhizal inoculation in existing Chilean afforestation programs.

  7. 铁强化微生物除磷的效能及机理%Efficiency and mechanism of ferric salt enhanced biological phosphorus removal

    Institute of Scientific and Technical Information of China (English)

    孙翠平; 周维芝; 赵海霞

    2015-01-01

    An efficient phosphorus (P)removal bacterium strain was screened from deep-sea bacteria,and phosphorus removal efficiency and mechanism by iron enhanced biological treatment were studied in the high salinity synthetic wastewater.The effects of molar ratio Fe(III)/P,initial pH on phosphorus removal and kinetics of iron enhanced bio-logical phosphorus removal were investigated by batch tests,and the surface morphology of bacteria was studied by SEM-EDS (scanning electron microscopy-energy dispersive X-ray spectroscopy).Results showed that the phosphorus removal efficiency of iron enhanced biological treatment was high and stable at more than 95% compared to those of in-dependent iron and biological treatment.Removal efficiency of phosphorus reached the maximum of 98.5% with molar ratio of Fe(III)and P being 1,which increased 30% than that of the biological treatment,whereas the maximum phos-phorus removal was 90% with molar ratio of Fe(III)and P ranging from 2 to 3 by independent iron treatment.Phos-phorus removal was mainly ascribed to bacterial growth and aided by iron,and pH was kept stable at about 7.2 when molar ratio of Fe(III)and P being not more than 1.Phosphorus removal was mainly by chemical precipitation with mo-lar ratio of Fe(III)and P being more than 1 because that the pH reduced to 5.5 or even lower by Fe(III)hydrolysis and significantly influenced bacterial growth.Phosphorus removal was kept at above 95% at pH of 6 ~9 with molar ratio of Fe(III)and P being 1.The dynamic pseudo-first-order model could fit the biological phosphorus removal process well, and the pseudo-second-order model could well describe the iron enhanced biological phosphorus removal without phos-phorus releasing for a long time.Except the uptake of part of the phosphorus by bacterial growth and bio-sorption by ex-tracellular polymeric substance,the hydroxyl phosphate iron complex compound and iron phosphorus precipitation in-duced by bacterium also contributed to the phosphorus

  8. Efficiency and mechanism of ferric salt enhanced biological phosphorus removal%铁强化微生物除磷的效能及机理

    Institute of Scientific and Technical Information of China (English)

    孙翠平; 周维芝; 赵海霞

    2015-01-01

    从深海菌中筛选出一株高效除磷菌,并研究了铁强化此除磷菌在高盐合成废水中的除磷效能及机理。通过批次试验研究了铁磷物质的量比、初始 pH 值对除磷效率的影响以及铁强化生物除磷的动力学,并利用扫描电镜和能谱分析对微生物表面形貌进行了研究。结果表明,与单独铁盐和生物除磷相比,铁强化微生物除磷效率更高效且稳定在95%以上。当 n(Fe(III))∶n(P)=1∶1时,铁强化微生物除磷的最大效率达98.50%,相比单纯生物除磷提高30%,而单独铁盐除磷 n(Fe(III))∶n(P)=2∶1~3∶1时,除磷率仅90%;当 n(Fe(III))∶n(P)≤1∶1时,铁强化微生物除磷以微生物除磷为主,铁盐辅助,处理后水 pH 中性且稳定;当物质的量比 n(Fe(III))∶n(P)>1∶1时,由于Fe(III)水解造成 pH 降低至5.50以下,微生物生长受抑,磷的去除主要靠化学沉淀。废水初始 pH 在6.0~9.0范围内,铁强化生物除磷去除率均在95%以上。准一级动力学模型能够很好地模拟生物除磷过程;准二级动力学模型能够很好地模拟铁强化生物除磷,且较长时间内无磷释放现象。铁强化生物除磷的机理包括:(1)细菌生长除磷以及胞外聚合物对磷的吸附;(2)在混合液中形成了羟基磷酸铁络合物;(3)在细菌表面形成了由细菌诱导的铁磷微沉淀。%An efficient phosphorus (P)removal bacterium strain was screened from deep-sea bacteria,and phosphorus removal efficiency and mechanism by iron enhanced biological treatment were studied in the high salinity synthetic wastewater.The effects of molar ratio Fe(III)/P,initial pH on phosphorus removal and kinetics of iron enhanced bio-logical phosphorus removal were investigated by batch tests,and the surface morphology of bacteria was studied by SEM-EDS (scanning electron microscopy

  9. Phosphorus, Agriculture & The Environment

    OpenAIRE

    Mullins, Gregory Lee

    2009-01-01

    Discusses potential environmental impacts of phosphorus, the functions of phosphorus in plants and animals, and the soil phosphorus cycle. Notes methods for controlling phosphorus losses to surface waters

  10. Enhanced solubility and ecological impact of atmospheric phosphorus deposition upon extended seawater exposure.

    Science.gov (United States)

    Mackey, Katherine R M; Roberts, Kathryn; Lomas, Michael W; Saito, Mak A; Post, Anton F; Paytan, Adina

    2012-10-01

    Atmospheric P solubility affects the amount of P available for phytoplankton in the surface ocean, yet our understanding of the timing and extent of atmospheric P solubility is based on short-term leaching experiments where conditions may differ substantially from the surface ocean. We conducted longer- term dissolution experiments of atmospheric aerosols in filtered seawater, and found up to 9-fold greater dissolution of P after 72 h compared to instantaneous leaching. Samples rich in anthropogenic materials released dissolved inorganic P (DIP) faster than mineral dust. To gauge the effect of biota on the fate of atmospheric P, we conducted field incubations with aerosol samples collected in the Sargasso Sea and Red Sea. In the Sargasso Sea phytoplankton were not P limited, and biological activity enhanced DIP release from aerosols, and aerosols induced biological mineralization of dissolved organic P in seawater, leading to DIP accumulation. However, in the Red Sea where phytoplankton were colimited by P and N, soluble P was rapidly consumed by phytoplankton following aerosol enrichment. Our results suggest that atmospheric P dissolution could continue over multiple days once reaching the surface ocean, and that previous estimates of atmospheric P deposition may underestimate the contribution from this source.

  11. The Relevance of Phosphorus and Iron Chemistry to the Recovery of Phosphorus from Wastewater: A Review.

    Science.gov (United States)

    Wilfert, Philipp; Kumar, Prashanth Suresh; Korving, Leon; Witkamp, Geert-Jan; van Loosdrecht, Mark C M

    2015-08-18

    The addition of iron is a convenient way for removing phosphorus from wastewater, but this is often considered to limit phosphorus recovery. Struvite precipitation is currently used to recover phosphorus, and this approach has attracted much interest. However, it requires the use of enhanced biological phosphorus removal (EBPR). EBPR is not yet widely applied and the recovery potential is low. Other phosphorus recovery methods, including sludge application to agricultural land or recovering phosphorus from sludge ash, also have limitations. Energy-producing wastewater treatment plants increasingly rely on phosphorus removal using iron, but the problem (as in current processes) is the subsequent recovery of phosphorus from the iron. In contrast, phosphorus is efficiently mobilized from iron by natural processes in sediments and soils. Iron-phosphorus chemistry is diverse, and many parameters influence the binding and release of phosphorus, including redox conditions, pH, presence of organic substances, and particle morphology. We suggest that the current poor understanding of iron and phosphorus chemistry in wastewater systems is preventing processes being developed to recover phosphorus from iron-phosphorus rich wastes like municipal wastewater sludge. Parameters that affect phosphorus recovery are reviewed here, and methods are suggested for manipulating iron-phosphorus chemistry in wastewater treatment processes to allow phosphorus to be recovered. PMID:25950504

  12. Interface Engineering for the Enhancement of Carrier Transport in Black Phosphorus Transistor with Ultra-Thin High-k Gate Dielectric

    Science.gov (United States)

    Ling, Zhi-Peng; Zhu, Jun-Tao; Liu, Xinke; Ang, Kah-Wee

    2016-05-01

    Black phosphorus (BP) is the most stable allotrope of phosphorus which exhibits strong in-plane anisotropic charge transport. Discovering its interface properties between BP and high-k gate dielectric is fundamentally important for enhancing the carrier mobility and electrostatics control. Here, we investigate the impact of interface engineering on the transport properties of BP transistors with an ultra-thin hafnium-dioxide (HfO2) gate dielectric of ~3.4 nm. A high hole mobility of ~536 cm2V‑1s‑1 coupled with a near ideal subthreshold swing (SS) of ~66 mV/dec were simultaneously achieved at room temperature by improving the BP/HfO2 interface quality through thermal treatment. This is attributed to the passivation of phosphorus dangling bonds by hafnium (Hf) adatoms which produces a more chemically stable interface, as evidenced by the significant reduction in interface states density. Additionally, we found that an excessively high thermal treatment temperature (beyond 200 °C) could detrimentally modify the BP crystal structure, which results in channel resistance and mobility degradation due to charge-impurities scattering and lattice displacement. This study contributes to an insight for the development of high performance BP-based transistors through interface engineering.

  13. Interface Engineering for the Enhancement of Carrier Transport in Black Phosphorus Transistor with Ultra-Thin High-k Gate Dielectric

    Science.gov (United States)

    Ling, Zhi-Peng; Zhu, Jun-Tao; Liu, Xinke; Ang, Kah-Wee

    2016-01-01

    Black phosphorus (BP) is the most stable allotrope of phosphorus which exhibits strong in-plane anisotropic charge transport. Discovering its interface properties between BP and high-k gate dielectric is fundamentally important for enhancing the carrier mobility and electrostatics control. Here, we investigate the impact of interface engineering on the transport properties of BP transistors with an ultra-thin hafnium-dioxide (HfO2) gate dielectric of ~3.4 nm. A high hole mobility of ~536 cm2V−1s−1 coupled with a near ideal subthreshold swing (SS) of ~66 mV/dec were simultaneously achieved at room temperature by improving the BP/HfO2 interface quality through thermal treatment. This is attributed to the passivation of phosphorus dangling bonds by hafnium (Hf) adatoms which produces a more chemically stable interface, as evidenced by the significant reduction in interface states density. Additionally, we found that an excessively high thermal treatment temperature (beyond 200 °C) could detrimentally modify the BP crystal structure, which results in channel resistance and mobility degradation due to charge-impurities scattering and lattice displacement. This study contributes to an insight for the development of high performance BP-based transistors through interface engineering. PMID:27222074

  14. Enhanced phosphorus removal from wastewater by growing deep-sea bacterium combined with basic oxygen furnace slag.

    Science.gov (United States)

    Zhou, Weizhi; Huang, Zhaosong; Sun, Cuiping; Zhao, Haixia; Zhang, Yuzhong

    2016-08-01

    As one solid waste with potential for phosphorus removal, application of slags in water treatment merits attention. But it was inhibited greatly by alkaline solution (pH>9.5) and cemented clogging generated. To give one solution, phosphorus removal was investigated by combining deep-sea bacterium Alteromonas 522-1 and basic oxygen furnace slag (BOFS). Results showed that by the combination, not only higher phosphorous removal efficiency (>90%) but also neutral solution pH of 7.8-8.0 were achieved at wide ranges of initial solution pH value of 5.0-9.0, phosphorus concentration of 5-30mg/L, salinity of 0.5-3.5%, and temperature of 15-35°C. Moreover, sedimentary property was also improved with lower amount of sludge production and alleviated BOFS cementation with increased porosity and enlarged particle size. These results provided a promising strategy for the phosphorus recovery with slags in large-scale wastewater treatment.

  15. Enhanced phosphorus removal from wastewater by growing deep-sea bacterium combined with basic oxygen furnace slag.

    Science.gov (United States)

    Zhou, Weizhi; Huang, Zhaosong; Sun, Cuiping; Zhao, Haixia; Zhang, Yuzhong

    2016-08-01

    As one solid waste with potential for phosphorus removal, application of slags in water treatment merits attention. But it was inhibited greatly by alkaline solution (pH>9.5) and cemented clogging generated. To give one solution, phosphorus removal was investigated by combining deep-sea bacterium Alteromonas 522-1 and basic oxygen furnace slag (BOFS). Results showed that by the combination, not only higher phosphorous removal efficiency (>90%) but also neutral solution pH of 7.8-8.0 were achieved at wide ranges of initial solution pH value of 5.0-9.0, phosphorus concentration of 5-30mg/L, salinity of 0.5-3.5%, and temperature of 15-35°C. Moreover, sedimentary property was also improved with lower amount of sludge production and alleviated BOFS cementation with increased porosity and enlarged particle size. These results provided a promising strategy for the phosphorus recovery with slags in large-scale wastewater treatment. PMID:27179297

  16. Enhanced Biological Phosphorus Removal in Anaerobic/Aerobic Sequencing Batch Reactor Supplied with Glucose as Carbon Source

    Institute of Scientific and Technical Information of China (English)

    LIU Yanan; YU Shui-li; JING Guo-lin; ZHAO Bing-jie; GUO Si-yuan

    2005-01-01

    Phosphorus removal performance in an aerobic/aerobic sequencing batch reactor (SBR) supplied with glucose as carbon source was investigated. It was found that there was no phosphate release concomitant with the storing of poly-β-hydroxyalkanoate (PHA) during the anaerobic phase. Whereas, glycogen was soon built up followed by rapid consumption, at the same time, glucose was depleted rapidly. Based on the analysis of different fractions of phosphorus in activated sludge, the relative ratio of organically bound phosphorus in sludge changed at the end of anaerobic and aerobic phases. The ratios were 45.3% and51.8% respectively. This showed that the polyphosphate broke down during the anaerobic phase to supply part of energy for PHA synthesis. The reason why there was no phosphate release might be the biosorption effect of extracellular exopolymers (EPS). It was also proved by the analysis of EPS with scanning electron microscopy (SEM)combined with energy dispersive spectrometry (EDS). The phosphorus weight percentage of EPS at the end of anaerobic phase was 9.22%.

  17. Wastewater resource recovery via the Enhanced Biological Phosphorus Removal and Recovery (EBP2R) process coupled with green microalgae cultivation

    DEFF Research Database (Denmark)

    Valverde Perez, Borja

    compatible to interface with ASM-2d. Therefore, the third part of the PhD project focusses on the development of a process model for micro-algal growth and substrate storage kinetics (referred to as ASM-A). To facilitate the integration in already well-stablished simulation platforms for wastewater treatment......, e.g., the Benchmark Simulation Models 1 and 2, ASM-A was implemented as an extension to the ASM-2d. A set of experiments at different laboratory-scales (microbatch, 1-litre and 24-litre SBR) was designed to generate data for model identification. Furthermore, an independent data set was used...... for model evaluation. The ASM-A can effectively predict the algal biomass growth, as well as the ammonium and phosphorus concentrations in the bulk liquid and the microbial stored phosphorus. Conversely, our results suggest that the maximum uptake rate parameter for nitrate can be significantly affected...

  18. Can deficit irrigation techniques be used to enhance phosphorus and water use efficiency and benefit crop yields?

    Science.gov (United States)

    Wright, Hannah R.; Dodd, Ian C.; Blackwell, Martin S. A.; Surridge, Ben W. J.

    2015-04-01

    Soil drying and rewetting (DRW) affects the forms and availability of phosphorus (P). Water soluble P has been reported to increase 1.8- to 19-fold after air-drying with the majority of the increase (56-100%) attributable to organic P. Similarly, in two contrasting soil types DRW increased concentrations of total P and reactive P in leachate, likely due to enhanced P mineralisation and physiochemical processes causing detachment of soil colloids, with faster rewetting rates related to higher concentrations of P. The intensity of drying as well as the rate of rewetting influences organic and inorganic P cycling. How these dynamics are driven by soil water status, and impact crop P acquisition and growth, remains unclear. Improving P and water use efficiencies and crop yields is globally important as both P and water resources become increasingly scarce, whilst demand for food increases. Irrigation supply below the water requirement for full crop evapotranspiration is employed by agricultural practitioners where water supply is limited. Regulated deficit irrigation describes the scheduling of water supply to correspond to the times of highest crop demand. Alternate wetting and drying (AWD) is applied in lowland irrigated rice production to avoid flooding at certain times of crop development, and has benefited P nutrition and yields. This research aims to optimise the benefits of P availability and uptake achieved by DRW by guiding deficit irrigation management strategies. Further determination of underlying processes driving P cycling at fluctuating soil moisture status is required. Presented here is a summary of the literature on DRW effects on soil P availability and plant P uptake and partitioning, in a range of soil types and cropping systems, with emphasis on alternate wetting and drying irrigation (AWD) compared to continuous flooding in lowland irrigated rice production. Soil water contents and matric potentials, and effects on P dynamics, are highly variable

  19. Approaches to the dimensioning of enhanced biological phosphorus elimination systems, taking dynamic simulation into account; Bemessungshinweise zur vermehrten biologischen Phosphorelimination unter Beruecksichtigung der dynamischen Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Scheer, H.

    1997-12-31

    With so many projects either planned or under construction, the question of the dimensioning of sewage treatment plants with enhanced biological phosphorus elimination (BIO-P) is becoming more and more important. A detailed search of literature established in how far dimensioning approaches or models were already available in the spring of 1994. These modelling approaches were critically examined and compared as to their practical applicability by means of parameter and sensitivity studies. For this purpose, they were programmed and the relevance of certain dimensioning parameters to biological phosphorus elimination was studied by means of a pilot plant. (orig./SR) [Deutsch] Der Auslegung von Klaeranlagen mit vermehrter biologischer Phosphorelimination (BIO-P) kommt bei der Vielzahl von Planungs- und Baumassnahmen eine immer wichtigere Bedeutung zu. Inwieweit fuer die Bemessung von Klaeranlagen mit BIO-P im Fruehjahr 1994 bereits auf vorhandene Bemessungsansaetze und -modelle zurueckgegriffen werden konnte, wurde mittels einer detaillierten Literaturstudie, untersucht. Diese Modellansaetze wurden im Hinblick auf ihre praxisorietierte Anwendbarkeit durch Parameter- und Sensitivitaetsstudien kritisch untersucht und verglichen. Hierzu wurden die verschiedenen, zum damaligen Zeitpunkt vorhandenen Ansaetze programmiert und die Auswirkungen wichtiger bemessungsrelevanter Parameter auf die BIO-P anhand einer Modellklaeranlage abgeschaetzt. (orig./SR)

  20. Enhancement of nitrogen and phosphorus removal from eutrophic water by economic plant annual ryegrass (Lolium multiflorum) with ion implantation.

    Science.gov (United States)

    Li, Miao; Sheng, Guo-ping; Wu, Yue-jin; Yu, Zeng-liang; Bañuelos, Gary S; Yu, Han-qing

    2014-01-01

    Severe eutrophication of surface water has been a major problem of increasing environmental concern worldwide. In the present study, economic plant annual ryegrass (Lolium multiflorum) was grown in floating mats as an economic plant-based treatment system to evaluate its potential after ion implantation for removing nutrients in simulated eutrophic water. The specific weight growth rate of L. multiflorum with ion implantation was significantly greater than that of the control, and the peroxidase, nitrate reductase, and acid phosphatase activities of the irradiated L. multiflorum were found to be greater than those plants without ion implantation. Higher total nitrogen (TN) and total phosphorus (TP) removal efficiencies were obtained for the L. multiflorum irradiated with 25 keV 5.2 × 10(16) N(+) ions/cm(2) and 30 keV 4.16 × 10(16) N(+) ions/cm(2), respectively (p phosphorus contents in the plant biomass with ion implantation were also greater than those in the control and were positively correlated with TN and TP supplied. L. multiflorum itself was directly responsible for 39-49 and 47-58 % of the overall N and P removal in the experiment, respectively. The research results suggested that ion implantation could become a promising approach for increasing phytoremediation efficiency of nutrients from eutrophic water by L. multiflorum.

  1. Immobilization of non-point phosphorus using stabilized magnetite nanoparticles with enhanced transportability and reactivity in soils

    Energy Technology Data Exchange (ETDEWEB)

    Pan Gang, E-mail: gpan@rcees.ac.c [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Li Lei [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhao Dongye [Department of Civil Engineering, Auburn University, AL 36830 (United States); Chen Hao [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2010-01-15

    Laboratory batch and column experiments were conducted to investigate the immobilization of phosphorus (P) in soils using synthetic magnetite nanoparticles stabilized with sodium carboxymethyl cellulose (CMC-NP). Although CMC-stabilized magnetite particles were at the nanoscale, phosphorus removal by the nanoparticles was less than that of microparticles (MP) without the stabilizer due to the reduced P reactivity caused by the coating. The P reactivity of CMC-NP was effectively recovered when cellulase was added to degrade the coating. For subsurface non-point P pollution control for a water pond, it is possible to inject CMC-NP to form an enclosed protection wall in the surrounding soils. Non-stabilized 'nanomagnetite' could not pass through the soil column under gravity because it quickly agglomerated into microparticles. The immobilized P was 30% in the control soil column, 33% when treated by non-stabilized MP, 45% when treated by CMC-NP, and 73% when treated by both CMC-NP and cellulase. - CMC-stabilized magnetite nanoparticles can effectively penetrate soil columns and immobilize phosphate in situ.

  2. Iron limitation in the Western Interior Seaway during the Late Cretaceous OAE 3 and its role in phosphorus recycling and enhanced organic matter preservation

    Science.gov (United States)

    Tessin, Allyson; Sheldon, Nathan D.; Hendy, Ingrid; Chappaz, Anthony

    2016-09-01

    The sedimentary record of the Coniacian-Santonian Oceanic Anoxic Event 3 (OAE 3) in the North American Western Interior Seaway is characterized by a prolonged period of enhanced organic carbon (OC) burial. This study investigates the role of Fe in enhancing organic matter preservation and maintaining elevated primary productivity to sustain black shale deposition within the Coniacian-Santonian-aged Niobrara Formation in the USGS #1 Portland core. Iron speciation results indicate the development of a reactive Fe limitation coeval with reduced bioturbation and increased organic matter preservation, suggesting that decreased sulfide buffering by reactive Fe may have promoted enhanced organic matter preservation at the onset of OAE 3. An Fe limitation would also provide a feedback mechanism to sustain elevated primary productivity through enhanced phosphorus recycling. Additionally our results demonstrate inconsistencies between Fe-based and trace metal redox reconstructions. Iron indices from the Portland core indicate a single stepwise change, whereas the trace metal redox proxies indicate fluctuating redox conditions during and after OAE 3. Using Fe speciation to reconstruct past redox conditions may be complicated by a number of factors, including Fe sequestration in diagenetic carbonate phases and efficient sedimentary pyrite formation in a system with limited Fe supply and high levels of export production.

  3. Understanding the impact of influent nitrogen concentration on granule size and microbial community in a granule-based enhanced biological phosphorus removal system.

    Science.gov (United States)

    Zou, Jinte; Li, Yongmei; Zhang, Lili; Wang, Ruyi; Sun, Jing

    2015-02-01

    To better understand the effect of influent nitrogen concentration on granule size and microbial community in a granule-based enhanced biological phosphorus removal system, three influent nitrogen concentrations were tested while carbon concentration was an unlimited factor. The results show that although ammonium and phosphate were well removed in the tested nitrogen concentration range (20-50 mg L(-1)), granule size, the amount of phosphate accumulating organisms (PAOs) and microbial activity were affected significantly. A possible mechanism for the effect of influent nitrogen concentration on granule size is proposed based on the experimental results. The increase in proteins/polysaccharides ratio caused by high influent nitrogen concentration plays a crucial role in granule breakage. The small granule size then weakens simultaneous nitrification-denitrification, which further causes higher nitrate concentration in the effluent and lower amount of PAOs in sludge. Consequently, phosphate concentration in the anaerobic phase decreases, which plays the secondary role in granule breakage. PMID:25496940

  4. 强化低碳源污水生物除磷的技术方式探究%Study on Technical Methods for Enhancing Biological Phosphorus Removal from Wastewater with Low Carbon Source

    Institute of Scientific and Technical Information of China (English)

    郝晓地; 衣兰凯; 王克巍

    2012-01-01

    以一营养物去除工艺——BNR为研究对象,分别采用试验与模拟,研究了通过厌氧上清液侧流磷回收和外加碳源方式对低碳源污水生物除磷的强化作用.试验结果与模拟预测双双显示,对COD/P值=50的实际生活污水实施30%的厌氧上清液旁路磷沉淀可明显强化生物除磷作用,使出水TP浓度从碳源抑制时的1.8 mgP/L下降至0.5 mgP/L以下.侧流磷回收不仅可回收40%的进水磷负荷,亦可节省27%的外加碳源.因此,厌氧上清液侧流磷回收与外加碳源对强化生物除磷作用有着异曲同工之处.模拟预测与试验结果几乎一致的演示表明,数学模拟技术可取代传统试验进行相关问题研究.%Based on a BNR process, enhancing biological phosphorus removal from wastewater with low carbon source by side-stream phosphorus recovery from anaerobic supernatant and addition of external carbon source was evaluated by both experiment and modeling. Both experiment and modeling demonstrate that side-stream phosphorus recovery from 30% anaerobic supernatant can effectively improve biological phosphorus removal from wastewater with the COD/P ratio of 50, which makes the effluent phosphorus lowered to^O. 5 mgP/L from 1. 8 mgP/L (limited by less carbon). Side-stream phosphorus recovery can not only recover 40% of the influent phosphorus loading, but also save 27% of external carbon source. Therefore, side-stream phosphorus recovery has the same function on enhancing biological phosphorus removal as addition of external carbon source. The simulation prediction matches the experimental results, which confirms that modeling is completely possible to replace conventional experiments for research purpose.

  5. 发酵液作为EBPR碳源的动力学模拟%Kinetic Simulation of Enhanced Biological Phosphorus Removal with Fermentation Broth as Carbon Source

    Institute of Scientific and Technical Information of China (English)

    张超; 陈银广

    2013-01-01

    发酵液是一种优质的碳源,能够提高生物除磷系统(EBPR)的除磷效果.采用基于碳源代谢的修正ASM2模型,能够较好地模拟发酵液作为EBPR碳源的动力学变化规律.发酵液作为EBPR唯一碳源时,系统中的异养菌不仅不对聚磷菌(PAO)的生长构成竞争关系,反而促进PAO的生长.发酵液作为实际污水的补充碳源时,优化了污水中的碳源组成,创造了有利于聚磷菌生长的环境,使EBPR中聚磷菌达到微生物总量的40%以上,比实际污水作为碳源的EBPR中的PAO含量提高了3.3倍.%As a high-quality carbon source,fermentation broth could promote the phosphorus removal efficiency in enhanced biological phosphorus removal (EBPR).The transformation of substrates in EBPR fed with fermentation broth was well simulated using the modified activated sludge model No.2 (ASM2) based on the carbon source metabolism.When fermentation broth was used as the sole carbon source,it was found that heterotrophic bacteria acted as a promoter rather than a competitor to the phosphorus accumulating organisms (PAO).When fermentation broth was used as a supplementary carbon source of real municipal wastewater,the wastewater composition was optimized for PAO growth; and the PAO concentration,which was increased by 3.3 times compared to that in EBPR fed with solely real municipal wastewater,accounting for about 40% of the total biomass in the reactor.

  6. Influence of enhanced biological phosphate removal on feedback of phosphorus from sludge treatment; Einfluss der erhoehten biologischen Phosphorelimination auf die Phosphorrueckbelastung aus der Schlammbehandlung

    Energy Technology Data Exchange (ETDEWEB)

    Jardin, N. [Inst. WAR, TH Darmstadt (Germany); Poepel, H.J. [Inst. WAR, TH Darmstadt (Germany)

    1995-06-01

    Phosphate release and phosphate fixation during sludge treatment of excess sludge was investigated with a pilot plant for enhanced biological phosphorus removal. The major part of the eliminated phosphorus in the pilot plant was due to the storage of polyphosphate in the excess sludge and was accompanied by an uptake of magnesium and potassium. Using separate thickening systems only a small P-feedback was observed, whereas with gravity thickeners a part of the polyphosphate was hydrolysed and phosphate was released into solution. Due to only a small transfer of the released phosphate from the sludge layer into the supernatant, the P-feedback was relatively low. As a result of a complete polyphosphate hydrolysis in stabilising systems, phosphate is released, but only a small part of the released phosphate remains in solution whereas the major fraction of the released phosphate was fixed by physico-chemical fixation mechanisms. (orig.) [Deutsch] Es wird ueber systematische Untersuchungen im halbtechnischen Massstab zum Einfluss der erhoehten biologischen Phosphorelimination auf die Phosphatrueckloesung und Phosphatrueckbelastung bei der Schlammbehandlung berichtet. Die durchgefuehrten Untersuchungen zeigten, dass der groesste Teil des im erhoehten Umfang gespeicherten Phosphors auf die Einlagerung von Polyphosphat zurueckzufuehren ist, wobei gleichzeitig auch Kalium- und Magnesiumionen aufgenommen werden. Die maschinellen Verfahren zur getrennten Ueberschussschlammeindickung verursachen nur eine geringe P-Rueckbelastung, waehrend bei der Schwerkrafteindickung das Polyphosphat teilweise hydrolysiert und als Phosphat rueckgeloest wird. Allerdings wurde nur ein geringer Transfer in den Ueberstand beobachtet, so dass die P-Rueckbelastung auch bei der Schwerkrafteindickung vergleichsweise gering war. Bei der Faulung und der aerob-thermophilen Stabilisierung wird das Polyphosphat vollstaendig hydrolisiert, aber nur ein kleiner Teil des freigesetzten Phosphats verbleibt in

  7. Influence of nitrite accumulation on "Candidatus Accumulibacter" population structure and enhanced biological phosphorus removal from municipal wastewater.

    Science.gov (United States)

    Zeng, Wei; Li, Boxiao; Wang, Xiangdong; Bai, Xinlong; Peng, Yongzhen

    2016-02-01

    A modified University of Cape Town (MUCT) process was used to treat real municipal wastewater with low carbon to nitrogen ratio (C/N). To our knowledge, this is the first study where the influence of nitrite accumulation on "Candidatus Accumulibacter" clade-level population structure was investigated during nitritation establishment and destruction. Real time quantitative PCR assays were conducted using the polyphosphate kinase 1 gene (ppk1) as a genetic marker. Abundances of total "Candidatus Accumulibacter", the relative distributions and population structure of the five "Candidatus Accumulibacter" clades were characterized. Under complete nitrification, clade I using nitrate as electron acceptor was below 5% of total "Candidatus Accumulibacter". When the reactor was transformed into nitritation, clade I gradually disappeared. Clade IID using nitrite as electron acceptor for denitrifying phosphorus (P) removal was always the dominant "Candidatus Accumulibacter" throughout the operational period. This clade was above 90% on average in total "Candidatus Accumulibacter", even up to nearly 100%, which was associated with good performance of denitrifying P removal via nitrite pathway. The nitrite concentrations affected the abundance of clade IID. The P removal was mainly completed by anoxic P uptake of about 88%. The P removal efficiency clearly had a positive correlation with the nitrite accumulation ratio. Under nitritation, the P removal efficiency was 30% higher than that under complete nitrification, suggesting that nitrite was appropriate as electron acceptor for denitrifying P removal when treating carbon-limited wastewater. PMID:26439519

  8. Study Progress on Biochemical Models for Enhanced Biological Phosphorus Removal%污水强化生物除磷的生化模型研究进展

    Institute of Scientific and Technical Information of China (English)

    彭永臻; 刘智波; Takashi MINO

    2006-01-01

    阐述了在污水强化生物除磷过程中生化模型的建立与发展,重点介绍了与聚磷菌有关的Mino模型,强调了在理解生化模型时应该注意的问题:所有聚磷菌生化模型都只是在试图描述发生在EBPR(Enhanced Biological Phosphorus Removal)生物群中的一些生物化学变化现象和规律(多聚磷酸盐的吸收和水解、PHA的合成与再利用).另外,还都假设所有具有EBPR能力的细菌都有着共同的代谢特征.所以,尽管这些生化模型有助于对整个EBPR过程的理解,但不应该拘泥于这些生化模型,只有通过对聚磷菌纯培养获得最终成功才能够彻底解决整个问题.

  9. PROGRESS ON DYNAMIC MODELS FOR ENHANCED BIOLOGICAL PHOSPHORUS REMOVAL%强化生物除磷动态模型研究进展

    Institute of Scientific and Technical Information of China (English)

    张立成; 王利平; 孙健

    2009-01-01

    概述了国内外强化生物除磷(EBPR)动态模型的研究进展,主要介绍了其中较成熟的ASM模型和代谢模型,并对这两类模型中的代表模型的运用条件、优缺点进行了评述.在此基础上指出了目前EBPR模型发展中存在的共性问题,并提出:代谢/ASM复合模型和杂交模型是EBPR模型未来发展的方向,但完善的EBPR模型的建立最终还要依赖于对EBPR代谢机理的透彻研究.%The establishment and development of the dynamic models in enhanced biological phosphorus removal process(EBPR)world wide were described, with focus on the operational conditions, advantages and disadvantages of two kinds of dynamic models: ASM models and Metabolic models. Based On this the general problems that exist in the development of EBPR models wre proposed. Further more, the future endeavours of dynamic models on EBPR were proposed: Combined metabolic/ASM models and hvbrid models. Nevertheless, the establishment of well-done models have to rely On the further research of metabolic mechanism in EBPR.

  10. Over-expression of the Arabidopsis proton-pyrophosphatase AVP1 enhances transplant survival, root mass, and fruit development under limiting phosphorus conditions.

    Science.gov (United States)

    Yang, Haibing; Zhang, Xiao; Gaxiola, Roberto A; Xu, Guohua; Peer, Wendy Ann; Murphy, Angus S

    2014-07-01

    Phosphorus (P), an element required for plant growth, fruit set, fruit development, and fruit ripening, can be deficient or unavailable in agricultural soils. Previously, it was shown that over-expression of a proton-pyrophosphatase gene AVP1/AVP1D (AVP1DOX) in Arabidopsis, rice, and tomato resulted in the enhancement of root branching and overall mass with the result of increased mineral P acquisition. However, although AVP1 over-expression also increased shoot biomass in Arabidopsis, this effect was not observed in tomato under phosphate-sufficient conditions. AVP1DOX tomato plants exhibited increased rootward auxin transport and root acidification compared with control plants. AVP1DOX tomato plants were analysed in detail under limiting P conditions in greenhouse and field trials. AVP1DOX plants produced 25% (P=0.001) more marketable ripened fruit per plant under P-deficient conditions compared with the controls. Further, under low phosphate conditions, AVP1DOX plants displayed increased phosphate transport from leaf (source) to fruit (sink) compared to controls. AVP1DOX plants also showed an 11% increase in transplant survival (Ptomato cultivars for increased proton pyrophosphatase gene expression could be useful when selecting for cultivars to be grown on marginal soils.

  11. Detection of Phosphorus, Sulphur, and Zinc in the Carbon-Enhanced Metal-Poor Star BD+44 493

    CERN Document Server

    Roederer, Ian U; Beers, Timothy C

    2016-01-01

    The carbon-enhanced metal-poor star BD+44 493 ([Fe/H]=-3.9) has been proposed as a candidate second-generation star enriched by metals from a single Pop III star. We report the first detections of P and S and the second detection of Zn in any extremely metal-poor carbon-enhanced star, using new spectra of BD+44 493 collected by the Cosmic Origins Spectrograph on the Hubble Space Telescope. We derive [P/Fe]=-0.34 +/- 0.21, [S/Fe]=+0.07 +/- 0.41, and [Zn/Fe]=-0.10 +/- 0.24. We increase by ten-fold the number of Si I lines detected in BD+44 493, yielding [Si/Fe]=+0.15 +/- 0.22. The solar [S/Fe] and [Zn/Fe] ratios exclude the hypothesis that the abundance pattern in BD+44 493 results from depletion of refractory elements onto dust grains. Comparison with zero-metallicity supernova models suggests that the stellar progenitor that enriched BD+44 493 was massive and ejected much less than 0.07 Msun of Ni-56, characteristic of a faint supernova.

  12. Phosphorus limitation enhances biofilm formation of the plant pathogen Agrobacterium tumefaciens through the PhoR-PhoB regulatory system

    DEFF Research Database (Denmark)

    Danhorn, T.; Hentzer, Morten; Givskov, Michael Christian;

    2004-01-01

    The plant pathogen Agrobacterium tumefaciens forms architecturally complex biofilms on inert surfaces. Adherence of A. tumefaciens C58 was significantly enhanced under phosphate limitation compared to phosphate-replete conditions, despite slower overall growth under low-phosphate conditions...... biofilms revealed that phosphate limitation increased both the overall attached biomass and the surface coverage, whereas the maximum thickness of the biofilm was not affected. Functions encoded on the two large plasmids of A. tumefaciens C58, pTiC58 and pAtC58, were not required for the observed phosphate......-borne copies of the genes, suggesting that this regulatory system might be essential. Expression of the A. tumefaciens phoB gene from a tightly regulated inducible promoter, however, correlated with the amount of biofilm under both phosphate-limiting and nonlimiting conditions, demonstrating that components...

  13. Detection of Phosphorus, Sulphur, and Zinc in the Carbon-enhanced Metal-poor Star BD+44 493

    Science.gov (United States)

    Roederer, Ian U.; Placco, Vinicius M.; Beers, Timothy C.

    2016-06-01

    The carbon-enhanced metal-poor star BD+44°493 ([Fe/H] = -3.9) has been proposed as a candidate second-generation star enriched by metals from a single Pop III star. We report the first detections of P and S and the second detection of Zn in any extremely metal-poor carbon-enhanced star, using new spectra of BD+44°493 collected by the Cosmic Origins Spectrograph on the Hubble Space Telescope. We derive [P/Fe] = -0.34 ± 0.21, [S/Fe] = +0.07 ± 0.41, and [Zn/Fe] = -0.10 ± 0.24. We increase by 10-fold the number of Si i lines detected in BD+44°493, yielding [Si/Fe] = +0.15 ± 0.22. The [S/Fe] and [Zn/Fe] ratios exclude the hypothesis that the abundance pattern in BD+44°493 results from depletion of refractory elements onto dust grains. Comparison with zero-metallicity supernova (SN) models suggests that the stellar progenitor that enriched BD+44°493 was massive and ejected much less than 0.07 M ⊙ of 56Ni, characteristic of a faint SN. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under NASA contract NAS 5-26555. These observations are associated with program GO-14231.

  14. A GAO hiding among the PAO: The role of the Propionivibrio spp. in biological phosphorus removal

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Albertsen, Mads; Stokholm-Bjerregaard, Mikkel;

    Enhanced biological phosphorus removal (EBPR) is widely used to remove phosphorus from wastewater. The process relies on polyphosphate accumulating organisms (PAOs) that are able to take up phosphorus in excess of what is needed for growth, whereby phosphorus can be removed from the wastewater...

  15. Transgenic barley (Hordeum vulgare L.) expressing the wheat aluminium resistance gene (TaALMT1) shows enhanced phosphorus nutrition and grain production when grown on an acid soil.

    Science.gov (United States)

    Delhaize, Emmanuel; Taylor, Phillip; Hocking, Peter J; Simpson, Richard J; Ryan, Peter R; Richardson, Alan E

    2009-06-01

    Barley (Hordeum vulgare L.), genetically modified with the Al(3+) resistance gene of wheat (TaALMT1), was compared with a non-transformed sibling line when grown on an acidic and highly phosphate-fixing ferrosol supplied with a range of phosphorus concentrations. In short-term pot trials (26 days), transgenic barley expressing TaALMT1 (GP-ALMT1) was more efficient than a non-transformed sibling line (GP) at taking up phosphorus on acid soil, but the genotypes did not differ when the soil was limed. Differences in phosphorus uptake efficiency on acid soil could be attributed not only to the differential effects of aluminium toxicity on root growth between the genotypes, but also to differences in phosphorus uptake per unit root length. Although GP-ALMT1 out-performed GP on acid soil, it was still not as efficient at taking up phosphorus as plants grown on limed soil. GP-ALMT1 plants grown in acid soil possessed substantially smaller rhizosheaths than those grown in limed soil, suggesting that root hairs were shorter. This is a probable reason for the lower phosphorus uptake efficiency. When grown to maturity in large pots, GP-ALMT1 plants produced more than twice the grain as GP plants grown on acid soil and 80% of the grain produced by limed controls. Expression of TaALMT1 in barley was not associated with a penalty in either total shoot or grain production in the absence of Al(3+), with both genotypes showing equivalent yields in limed soil. These findings demonstrate that an important crop species can be genetically engineered to successfully increase grain production on an acid soil.

  16. Towards high through-put biological treatment of municipal wastewater and enhanced phosphorus recovery using a hybrid microfiltration-forward osmosis membrane bioreactor with hydraulic retention time in sub-hour level.

    Science.gov (United States)

    Qiu, Guanglei; Zhang, Sui; Srinivasa Raghavan, Divya Shankari; Das, Subhabrata; Ting, Yen-Peng

    2016-11-01

    This work uncovers an important feature of the forward osmosis membrane bioreactor (FOMBR) process: the decoupling of contaminants retention time (CRT) and hydraulic retention time (HRT). Based on this concept, the capability of the hybrid microfiltration-forward osmosis membrane bioreactor (MF-FOMBR) in achieving high through-put treatment of municipal wastewater with enhanced phosphorus recovery was explored. High removal of TOC and NH4(+)-N (90% and 99%, respectively) was achieved with HRTs down to 47min, with the treatment capacity increased by an order of magnitude. Reduced HRT did not affect phosphorus removal and recovery. As a result, the phosphorus recovery capacity was also increased by the same order. Reduced HRT resulted in increased system loading rates and thus elevated concentrations of mixed liquor suspended solids and increased membrane fouling. 454-pyrosequecing suggested the thriving of Bacteroidetes and Proteobacteria (especially Sphingobacteriales Flavobacteriales and Thiothrix members), as well as the community succession and dynamics of ammonium oxidizing and nitrite oxidizing bacteria. PMID:27498011

  17. Local radiative treatment of hepatocellular cancer with phosphorus-32 glassmicrospheres to enhance the efficacy of hepatic artery chemoembolism andpossibly related with MDR expressed P-glycoprotein

    Institute of Scientific and Technical Information of China (English)

    Zao Jiang; Lu Liu; Wen Fang; Wei Zhang Shou; Dong Sheng Zhang; Mei Mei Dai

    2000-01-01

    AIM To investigate the local effect of phosphorus-32 glass microspheres (32 P-GMS) on hepatocellularcancer and its relation with chemoembolism.MVIETHODS (① Thirty-two BALB/c nu/nu nude mice were divided randomly into four groups, control groupand 3 treatment groups. Every mouse was implanted with human liver cancer cell line subset (H-CS). 32p-GMS amalgamated in iodine oil was injected directly into the tumor mass. After 2 wk, all animals but thosein the control group, were injected with 32p-GMS in the dosage of 880cGY, 1760cGY and 3520cGY formouce groups Ⅰ, Ⅱ and Ⅲ respectively. The histological reactions of tumor mass were observed; multidrugresistance (MDR) expressed p-glycoprotein was detected by flow cytometry. ②Forty-three patients withhepatocellular carcinoma based on the evidence from B sonography or CT and serum AFP >400 ng/mL orcytological and histological evidences in some cases with the negative AFP were divided randomly into twogroups, group Ⅰ treated with 32p-GMS (absorbed dose of 50Gy- 100Gy) alone, group Ⅱ treated with 32p-GMS and chemotherapeutics (half-dosage, doxorubicin 20mg/m2, cisplatin 30mg/m2). 32 P-GMS wasinjected through intra hepatic artery in these cases with single massive type and multi-nodular type. Everypatient was repeatedly treated with this method for 2 - 3 times. For evaluating the therapeutic results. Themodified WHO criteria for tumor therapy standard is the.RESULTS (①) Animal bearing tumors showed that the mass decreased markedly and the inhibitive ratesattained 66.53%, 83.06% and 91.53% in the absorbed doses ranged form 880GY, 1760Gy and 3520Gyrespectively (P<0.05, ANOVA). Flow cytometry detected MDR expressed p-glycoprotein decreased from68.2 ± 4.6 in control to 43.6 ± 3.4, 35.3 ± 4.3 and 33.2 ± 3.8 (P<0.05, compared with control, t-test) inthe cells from the tumors. (②) The foci in group Ⅰ revealed decreased in size dramatically with effective rate of71.43%, compared with 86.36% in the group Ⅱ (P<0

  18. Improving phosphorus availability in an acid soil using organic amendments produced from agroindustrial wastes.

    Science.gov (United States)

    Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab

    2014-01-01

    In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments. PMID:25032229

  19. Improving phosphorus availability in an acid soil using organic amendments produced from agroindustrial wastes.

    Science.gov (United States)

    Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab

    2014-01-01

    In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

  20. Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

    Directory of Open Access Journals (Sweden)

    Huck Ywih Ch’ng

    2014-01-01

    Full Text Available In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp. to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus, and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

  1. 化学强化生物除磷工艺系统优化%Optimization of Chemically Enhanced Biological Phosphorus Removal Process

    Institute of Scientific and Technical Information of China (English)

    于丹; 卢钢; 连小英; 关卫省

    2011-01-01

    In simultaneous deposition phosphorus removal process, first the biological phosphorus removal rate is forecasted according to the effluent quality of primary sedimentation tank, then the dosage of chemicals is derived from the formula of chemicals dosage for chemical phosphorus removal obtained by the jar test, and finally the variable addition of chemicals is achieved by automatic control system.The variable addition of chemicals enables the effluent quality to meet the discharge standard and reduces the discharge of sludge from chemical phosphorus removal to achieve energy-saving and consumption reduction.%在同步沉析除磷工艺中,首先由初沉池出水水质预测出生物除磷量,然后根据烧杯试验求得的化学除磷药剂投量公式求出药剂投量,最后通过除磷自控系统实现药剂的变量投加.药剂的变量投加不仅使出水水质满足排放标准,而且减少了化学除磷污泥的排放量,达到了节能减排的目的.

  2. Displacement of phosphorus in structured soils

    OpenAIRE

    Djodjic, Faruk

    2001-01-01

    Phosphorus losses from agriculture may enhance eutrophication of fresh water bodies. This thesis focuses on preferential flow as a phosphorus transport pathway. Both lysimeter and field plot observations were conducted to evaluate the significance of preferential flow for P losses and to test management practices to reduce P losses. A decision support system was also developed to identify critical source areas, to diagnose probable causes of P losses and to prescribe appropriate site-specific...

  3. Formation of granular sludge and its mechanism in enhanced process of biological phosphorus removal%强化生物除磷体系中颗粒污泥的形成及机理探讨

    Institute of Scientific and Technical Information of China (English)

    王然登; 彭永臻; 吴昌永; 李晓玲; 马勇

    2011-01-01

    以实验室小试SBR反应器为载体接种普通活性污泥,研究了强化生物除磷系统对颗粒污泥形成的促进作用并探讨了其形成机理.试验结果发现:在生物脱氮运行阶段,SBR中的活性污泥能维持较稳定的絮体状态,平均SVI为138.9 ml·g-1;当系统转为生物除磷方式运行时,随着除磷效果的好转,反应器中的污泥逐渐转化为颗粒污泥,平均SVI降低至74.1 ml·g-1,颗粒污泥的平均粒径为0.8 mm.因此,SBR生物除磷系统有利于颗粒污泥的形成.试验发现在强化生物除磷系统厌氧释磷的过程中会有带正电的微粒大量生成,它们可以作为颗粒污泥的晶核吸附带负电的细胞体,进而促进颗粒污泥的形成.强化生物除磷颗粒污泥系统有着较为稳定的磷去除性能,除磷效率接近100%.%The promoting effect on the formation of granular sludge by inoculating activated sludge in the enhanced process of biological phosphorus removal was studied in a laboratory-scale sequencing batch reactor (SBR). The results showed that the activated sludge kept in stabilized flocculent state at biological denitrification stage, and the average SVI was 138.9 ml·g-1, while at biological de-phosphorus one the activated sludge flocs became granular sludge gradually as the performance of P removal became better. The average SVI decreased to 74.1 ml·g-1 and the average diameter of the granules was 0.8 mm. Therefore, the biological phosphorus removal process performed in SBR favored for the formation of granular sludge. Moreover, it was found that a lot of positive charged particles were formed with the release of phosphorus at the anaerobic stage in the biological de-phosphorus process. These particles could serve as the cores of granules to attract the negative charged cells and stimulate the granulation. The granular sludge system of enhancing biological de-phosphorus have an excellent ability for the removal of phosphorus. The average removal rate

  4. Species distribution in relation to varying temperatures of microorganisms with enhanced biological phosphorus storage; Zusammensetzung und Temperaturabhaengigkeit der Mikroflora phosphatspeichernder belebter Schlaemme

    Energy Technology Data Exchange (ETDEWEB)

    Helmer, C. [Hannover Univ. (Germany). Inst. fuer Siedlungswasserwirtschaft und Abfalltechnik; Kunst, S. [Hannover Univ. (Germany). Inst. fuer Siedlungswasserwirtschaft und Abfalltechnik

    1996-01-01

    A continuous flow pilot plant with a mixed population of activated sludge was used to investigate the influence of varying temperatures between 20 C and 5 C on the efficiency of biological phosphorus removal and the composition of bacterial communities. Besides the registration of parameters, determinating - according to the models - the biological phosphorus removal, the sludge microflora was analysed regularly. Nearly all isolated strains were tested for their ability of polyphosphate storage. (orig.) [Deutsch] In einer kontinuierlich betriebenen Laborklaeranlage wurde an den Mischbiozoenosen belebter Schlaemme der Einfluss von Temepraturvariationen zwischen 20 C und 5 C auf die vermehrte biologische Phosphorelimination und die Zusammensetzung der Bakterienflora untersucht. Neben einer Erfassung der prozessbestimmenden Parameter der biologischen Phosphorelimination wurden regelmaessig Populationsanalysen und Versuche zum Polyphosphatspeichervermoegen der isolierten Reinkulturen durchgefuehrt. (orig.)

  5. Phosphorus poisoning in waterfowl

    Science.gov (United States)

    Coburn, D.R.; DeWitt, J.B.; Derby, J.V., Jr.; Ediger, E.

    1950-01-01

    Black ducks and mallards were found to be highly susceptible to phosphorus poisoning. 3 mg. of white phosphorus per kg. of body weight given in a single dose resulted in death of a black duck in 6 hours. Pathologic changes in both acute and chronic poisoning were studied. Data are presented showing that diagnosis can be made accurately by chemical analysis of stored tissues in cases of phosphorus poisoning.

  6. Kinetic analysis of anaerobic phosphorus release during biological phosphorus removal process

    Institute of Scientific and Technical Information of China (English)

    DOU Junfeng; LUO Guyuan; LIU Xiang

    2007-01-01

    Enhanced biological phosphorus removal(EBPR)is a commonly used and sustainable method for phosphorus removal from wastewater.Poly-β-hydroxybutyrate(PHB),polyphosphate,and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation organisms.The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release,which is very important for controlling the performance of EBPR.To obtain the mechanism and kinetic character of anaerobic phosphorus release,a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit of the biological phosphorus removal system in this study.The results showed that the volatile suspended solid(vss)had an increasing trend,while the mixed liquid suspended sludge(MLSS)and ashes were reduced during the anaerobic phosphorus release process.The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms is exhausted.Under the condition of lower initial HAc-COD,HAc became the limiting factor after some time for anaerobic HAc uptake.Under the condition of higher initial HAc-COD,HAc uptake was stopped because of the depletion of glycogen in the microorganisms.The mean ratio of △ρP/△ρPHB,△ρGLY/△ρPHB,△ρP/△COD,and △ρPHB/△COD was 0.48,0.50,0.44.and 0.92.respectively,which was nearly the same as the theoretical value.The calibrated kinetic parameters of the HAc-uptake and phosphorus-release model were evaluated as Kgly was 0.005,and KCOD was 3 mg/L.An apparently linear correlation was observed between the ratio of △ρP/△COD and pH of the solution,and the equation between them was obtained in this study.

  7. Role of extracellular exopolymers on biological phosphorus removal

    Institute of Scientific and Technical Information of China (English)

    LIU Ya-nan; XUE Gang; YU Shui-li; ZHAO Fang-bo

    2006-01-01

    Three sequencing batch reactors supplied with different carbon sources were investigated. The system supplied with glucose gained the best enhanced biological phosphorus removal although all of the three reactors were seeded from the same sludge. With the measurement of poly-β-hydroxyalkanoate (PHA) concentration, phosphorus content in sludge and extracellular exopolymers (EPS) with scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS), it was found that the biosorption effect of EPS played an important role in phosphorus removal and that the amount of PHA at the end of anaerobic phase was not the only key factor to determine the following phosphorus removal efficiency.

  8. A2/O工艺强化反硝化除磷控制策略研究%STUDY ON THE STRATEGIES OF ENHANCING DENITRIFYING PHOSPHORUS REMOVAL IN THE ANAEROBIC-ANOXIC-OXIC PROCESS

    Institute of Scientific and Technical Information of China (English)

    姚晓园

    2012-01-01

    Based on the conventional anaerobic-anoxic-oxic process, the nutrient removal ability of AVO process treating low C/N domestic sewage was improved by installing the pre-anoxic zone (forming the pre-anoxic/anaerobic/anoxic/aerobic process), adding the external carbon sources. The results showed that, these strategies enhanced the AVO reactor removal efficiency of COD, TN and TP, the removal rates of COD, TN and TP reached 92% -98% and 85% respectively. The system showed an obvious denitrifying phosphorus removal phenomenon, the phosphorus removal proportion by the anoxic zone reached up to 17.18% of the total phosphorus removal. The occurrence of denitrifying phosphorus removal decreased the affect of the carbon sources to the AVO process nutrient removal ability, raising the carbon utilizing efficiency. This paper offered an experience to the waste water treatment plant treating low C/N domestic sewage with the A2/O process.%在传统A2/O工艺的基础上,通过设立预缺氧区(即建立A-A2/O工艺)、外加碳源等手段,强化A2/O工艺处理低C/N生活污水的脱氮除磷能力.试验结果表明,经过强化后的A2/O反应器对COD、TN及TP去除效果良好,COD、TN及TP的去除率分别为92%、98%、85%.系统表现出明显的反硝化除磷现象,缺氧区除磷量占总除磷量的17.18%.反硝化除磷现象的产生降低了碳源缺乏对A2/O工艺脱氮除磷性能的影响,提高碳源的利用效率.为采用A2/O工艺处理低C/N生活污水的污水处理厂提供理论依据.

  9. Glacial atmospheric phosphorus deposition

    Science.gov (United States)

    Kjær, Helle Astrid; Dallmayr, Remi; Gabrieli, Jacopo; Goto-Azuma, Kumiko; Hirabayashi, Motohiro; Svensson, Anders; Vallelonga, Paul

    2016-04-01

    Phosphorus in the atmosphere is poorly studied and thus not much is known about atmospheric phosphorus and phosphate transport and deposition changes over time, though it is well known that phosphorus can be a source of long-range nutrient transport, e.g. Saharan dust transported to the tropical forests of Brazil. In glacial times it has been speculated that transport of phosphorus from exposed shelves would increase the ocean productivity by wash out. However whether the exposed shelf would also increase the atmospheric load to more remote places has not been investigated. Polar ice cores offer a unique opportunity to study the atmospheric transport of aerosols on various timescales, from glacial-interglacial periods to recent anthropogenic influences. We have for the first time determined the atmospheric transport of phosphorus to the Arctic by means of ice core analysis. Both total and dissolved reactive phosphorus were measured to investigate current and past atmospheric transport of phosphorus to the Arctic. Results show that glacial cold stadials had increased atmospheric total phosphorus mass loads of 70 times higher than in the past century, while DRP was only increased by a factor of 14. In the recent period we find evidence of a phosphorus increase over the past 50 yrs in ice cores close to human occupation likely correlated to forest fires. References: Kjær, Helle Astrid, et al. "Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores." Environmental science & technology 47.21 (2013): 12325-12332. Kjær, Helle Astrid, et al. "Greenland ice cores constrain glacial atmospheric fluxes of phosphorus." Journal of Geophysical Research: Atmospheres120.20 (2015).

  10. Phosphorus/sulfur Co-doped porous carbon with enhanced specific capacitance for supercapacitor and improved catalytic activity for oxygen reduction reaction

    Science.gov (United States)

    Zhou, Yao; Ma, Ruguang; Candelaria, Stephanie L.; Wang, Jiacheng; Liu, Qian; Uchaker, Evan; Li, Pengxi; Chen, Yongfang; Cao, Guozhong

    2016-05-01

    Phosphorus (P)/sulfur (S) co-doped porous carbon derived from resorcinol and furaldehyde are synthesized through one-step sol-gel processing with the addition of phosphorus pentasulfide as P and S source followed with freeze-drying and pyrolysis in nitrogen. The P/S co-doping strategy facilitates the pore size widening both in micropore and mesopore regions, together with the positive effect on the degree of graphitization of porous carbon through elimination of amorphous carbon through the formation and evaporation of carbon disulfide. As an electrode for supercapacitor application, P/S co-doped porous carbon demonstrates 43.5% improvement on specific capacitance of the single electrode compared to pristine porous carbon in organic electrolyte at a current of 0.5 mA due to the P-induced pseudocapacitive reactions. As for electrocatalytic use, promoted electrocatalytic activity and high resistance to crossover effects of oxygen reduction reaction (ORR) in alkaline media are observed after the introduction of P and S into porous carbon. After air activation, the specific capacitance of the single electrode of sample PS-pC reaches up to 103.5 F g-1 and an improved oxygen reduction current density.

  11. Effects of phytase on enhancement of phosphorus utilization from plant materials in bybrid catfish [Clarias macrocephalus (Gunther x Clarias gariepinus (Burchell

    Directory of Open Access Journals (Sweden)

    Phromkunthong,W.

    2005-01-01

    Full Text Available Hybrid catfish of initial weight 5.57-5.72g were studied in 235-1 glass tanks filled with 1801 water and closed-recirculation system with 0.8 l/m flow rate was attached. Complete randomized design was employed in which there were three replications (20 fingerlings each in each of nine treatments. The experimental period was 10 weeks. Formula 1 feed was the control in which fishmeal and soybean meal were used as protein source and was nutritionally suitable for catfish. In formulae 2-6 Feeds, only plant materials were used as feed components and sprayed phytase was aplied at 0,250,500,750 and 1,000 unit/kg feed. For formula 7-9 feeds, phosphorus from dicalcium phosphate (DCP at 0.1,0.2 and 0.3% was supplemented. The results showed that the supplementation of 500 unit/kg feed as well as of 0.2% phosphorus were the most effective in improving the weight gain, specific growth rate and feed efficiency (FCR, PER and ANPU. The supplementation of phytase as well as of DCP elevated the bone as well as in the whole body while the blood parameters were not markedly affected.

  12. Enhanced Visibility of MoS2, MoSe2, WSe2 and Black-Phosphorus: Making Optical Identification of 2D Semiconductors Easier

    Directory of Open Access Journals (Sweden)

    Gabino Rubio-Bollinger

    2015-10-01

    Full Text Available We explore the use of Si3N4/Si substrates as a substitute of the standard SiO2/Si substrates employed nowadays to fabricate nanodevices based on 2D materials. We systematically study the visibility of several 2D semiconducting materials that are attracting a great deal of interest in nanoelectronics and optoelectronics: MoS2, MoSe2, WSe2 and black-phosphorus. We find that the use of Si3N4/Si substrates provides an increase of the optical contrast up to a 50%–100% and also the maximum contrast shifts towards wavelength values optimal for human eye detection, making optical identification of 2D semiconductors easier.

  13. Effect of high calcium concentration influents on enhanced biological phosphorus removal process; Efecto del proceso de eliminacion biologica de fosforo en enfluentes con elevadas concentraciones de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Montoya Martinez, T.; Aguado Garcia, D.; Ferrer Polo, J.

    2010-07-01

    In this work, the effect of calcium concentration in wastewater on the polyphosphate accumulating organisms (PAO) is investigated as well as its influence in PAO metabolism, specifically in the Y{sub P}O4 (ratio between phosphorus release and acetic acid uptake). For this study a sequencing batch reactor (SBR) anaerobic-aerobic was used, in which the PAO enriched biomass was exposed to different calcium concentrations in the influent wastewater. The results indicate that until a given calcium level in the influent wastewater (35 mg Ca/l) the metabolism is not affect, but higher calcium concentrations lead to significant Y{sub P}O4 decline. (Author) 18 refs.

  14. Nutrient removal at the waste water treatment plant at Wathlingen. Special aspects of the enhanced biological phosphorus removal; Naehrstoffelemination auf der Klaeranlage Wathlingen. Besonderheiten bei der erhoehten biologischen Phosphatelimination

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, D. [Fachhochschule Suderburg (Germany); Fladerer, F. [Fachhochschule Suderburg (Germany)

    1996-01-01

    The article describes the problem of the nutrient removal in communal wastewater treatment plants. As an example the investigations about the optimisation of the denitrification and the enhanced biological phosphorus removal on the Wathlingen Wastewater Treatment Plant are explained. In this case the most important subjects are the anaerobic P-release despite a high amount of nitrate in the return sludge entering the anerobic tank, followed by an anoxic P-uptake in the denitrification zone before entering the aerobic tank for nitrification. Furthermore there is a short description of improvement measures carried out. The obtained effluent values show the success of these improvements. The specific P-dynamic in the treatment system requires conclusions supporting the optimisation of the nutrient removal in treatment plants using enhanced biological P-elimination and denitrification before nitrification. (orig.) [Deutsch] Der Artikel befasst sich mit der Problematik der Naehrstoffelimination auf kommunalen Klaeranlagen. Am Beispiel der Untersuchungen zur Optimierung der Dentrifikation und erhoehten biologischen Phosphorelimination auf der Klaeranlage Wathlingen werden Besonderheiten der biologischen P-Elimination dargestellt. Dabei geht es vor allem um eine anaerobe P-Freisetzung bei intermittierender Schlammumwaelzung im anaeroben Becken und gleichzeitigen hohen Nitrateintraegen ueber den Ruecklaufschlamm. Ebenso erfolgt die Darstellung der sich anschliessenden anoxischen P-Aufnahme im vorgeschalteten Denitrifikationsbecken. Des weiteren werden die druchgefuehrten Optimierungen kurz beschrieben und die damit erzielten Ablaufwerte aufgefuehrt. Schlussfolgerungen fuer die Prozessfuehrung bei Anlagenkonfigurationen mit biologischer P-Elimination und vorgeschalteter Denitrifikation ergeben sich aus dem Phaenomen der anoxischen Phosphataufnahme. (orig.)

  15. Organic chemistry of elemental phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Milyukov, V A; Budnikova, Yulia H; Sinyashin, Oleg G [A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Centre of the Russian Academy of Sciences, Kazan (Russian Federation)

    2005-09-30

    The principal achievements and the modern trends in the development of the chemistry of elemental phosphorus are analysed, described systematically and generalised. The possibilities and advantages of the preparation of organophosphorus compounds directly from white phosphorus are demonstrated. Attention is focused on the activation and transformation of elemental phosphorus in the coordination sphere of transition metal complexes. The mechanisms of the reactions of white phosphorus with nucleophilic and electrophilic reagents are discussed. Electrochemical approaches to the synthesis of organic phosphorus derivatives based on white phosphorus are considered.

  16. phosphorus retention data and metadata

    Data.gov (United States)

    U.S. Environmental Protection Agency — phosphorus retention in wetlands data and metadata This dataset is associated with the following publication: Lane , C., and B. Autrey. Phosphorus retention of...

  17. Long-term population dynamics and in situ physiology in activated sludge systems with enhanced biological phosphorus removal operated with and without nitrogen removal

    DEFF Research Database (Denmark)

    Lee, N.; Nielsen, P.H.; Aspegren, H.;

    2003-01-01

    Quantitative fluorescence in situ hybridization (FISH) and the combination of FISH with microautoradiography (MAR) were used in order to study the long-term population dynamics (2.5 years) and the in situ physiology in two parallel activated sludge pilot systems with enhanced biological phosphoru...

  18. 强化生物除磷系统主要微生物及其代谢机理研究进展%Review on the main microorganisms and their metabolic mechanisms in enhanced biological phosphorus removal (EBPR) systems

    Institute of Scientific and Technical Information of China (English)

    孙雪; 朱为静; 王亮; 吴伟祥

    2014-01-01

    强化生物除磷(enhanced biological phosphorus removal,EBPR)工艺在废水除磷处理中应用广泛.主要功能微生物及其代谢机理的研究是有效调控EBPR工艺稳定运行与效能提升的基础.本文选取EBPR系统中最主要的两类微生物(聚磷菌和聚糖菌),从底物吸收机制、糖酵解途径、TCA途径的贡献以及聚磷菌和聚糖菌的代谢相似性等方面对这些微生物的代谢机理进行综述,评价了分子生物学技术在研究EBPR系统微生物学及其代谢机理方面的应用现状,在此基础上对EBPR系统今后的研究方向进行了展望.

  19. Biological Phosphorus Removal in a Moving Bed Biofilm Reactor

    OpenAIRE

    Helness, Herman

    2007-01-01

    Phosphorus (P) and nitrogen (N) removal from municipal wastewater is performed to prevent or reduce eutrophication in the receiving water.Both P and N can be removed physical/chemically as well as biologically. While biological processes have always dominated in N-removal, chemical P-removal is used in many cases. Biological P-removal using enhanced biological phosphorus removal (EBPR) is normally carried out in suspended culture (activated sludge) processes while biological N-removal (throug...

  20. Nitrogen and phosphorus intake by phytoplankton in the Xiamen Bay

    Institute of Scientific and Technical Information of China (English)

    林彩; 林辉; 贺青; 许焜灿; 吴省三; 张元标; 陈金民; 陈宝红; 林力斌; 卢美鸾; 陈维芬; 汤荣坤; 暨卫东

    2010-01-01

    This paper describes a time series experiment examining the nitrogen and phosphorus intake of natural phytoplankton communities by a microcosms approach.Seawater samples containing natural phytoplankton communities were collected from waters around Baozhu Islet in inner Xiamen Bay and around Qingyu Islet in the outer bay.The goal was to elucidate the relationship between phytoplankton population enhancement,the biological removal of nitrogen and phosphorus from the seawater,and the phytoplankton nitrogen an...

  1. Biological phosphorus and nitrogen removal in a single sludge system

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Hans

    1996-05-01

    The primary aim of this thesis was to investigate the process stability of a single sludge activated system designed for the combined operation of enhanced biological phosphorus removal (EBPR) and nitrogen removal. A pilot plant at the Sjoelunda wastewater treatment plant in Malmoe, Sweden, has formed the basis for the investigation. The pilot plant study showed that the concentration of total phosphorus on average was low in the effluent, below 0.5 mg P/l. Simultaneously with the highest concentrations of phosphorus in the effluent, the lowest COD/P ratios in the effluent were recorded. A recurrent pattern of high concentrations of phosphorus was observed every year in July, which is the industrial holiday month in Sweden. Other instances of increased phosphorus concentrations in the secondary effluent illustrate the effect of prolonged periods of rain. Increasing flow rates due to rain lead to a dilution and a change in the composition of the COD in the influent wastewater. The COD/P and VFA/P ratios decrease with decreasing concentrations of COD. It was also shown that high removal ratios of both nitrogen and phosphorus during long periods are possible. The nitrogen removal was stable during the whole investigated period, whereas the phosphorus removal was unstable during prolonged periods with low concentrations of COD in the influent water. The combined biological phosphorus and nitrogen removal process implies that during these periods the risk of recirculating nitrate to the anaerobic reactor increases. Such a recirculation both stabilizes the nitrogen removal and withdraws some of the readily degradable organic material from the bio-P bacteria. The main conclusion of this study is that a phosphorus limited EBPR process can cope with the day to day variations, but occasionally, measures have to be taken if the demands for phosphorus removal are stringent. 49 refs, 8 figs, 1 tab

  2. Nitrogen and phosphorus intake by phytoplankton in the Xiamen Bay

    Science.gov (United States)

    Lin, Cai; Li, Hui; He, Qing; Xu, Kuncan; Wu, Shengsan; Zhang, Yuanbiao; Chen, Jinmin; Chen, Baohong; Lin, Libin; Lu, Meiluan; Chen, Weifen; Tang, Rongkun; Ji, Weidong

    2010-01-01

    This paper describes a time series experiment examining the nitrogen and phosphorus intake of natural phytoplankton communities by a microcosms approach. Seawater samples containing natural phytoplankton communities were collected from waters around Baozhu Islet in inner Xiamen Bay and around Qingyu Islet in the outer bay. The goal was to elucidate the relationship between phytoplankton population enhancement, the biological removal of nitrogen and phosphorus from the seawater, and the phytoplankton nitrogen and phosphorus intake ratio based on nitrogen and phosphorus removal from seawater by phytoplankton, to provide a basis for detecting prewarning conditions for red tide and the assessment of red tide events. Two key results were obtained: 1. During the experiment, the nitrogen and phosphorus seawater concentrations in samples from these two sites were negatively and closely correlated to the logarithm of the phytoplankton cell concentration and to the value of the apparent oxygen increment. The ratio of the intake coefficients was 3.5:1 for phosphorus and 1.1:1 for nitrogen for the phytoplankton between these samples from around Baozhu Islet and Qingyu Islet, respectively. This indicates that the intake capabilities of phytoplankton for nitrogen in the two waters are essentially identical. However, for phosphorus, the capability was much higher in the Baozhu Islet waters than the Qingyu Islet waters. In other words, the phytoplankton in Qingyu Islet waters produced more biomass while consuming the same amount of phosphorus as the other waters; 2. The phytoplankton nitrogen and phosphorus intake ratio from the Baozhu Islet and Qingyu Islet waters was 20:1 and 36:1, respectively. The latter waters had a significantly higher ratio than the former and both were higher than the Redfield Ratio. These results indicate that nitrogen and phosphorus intake ratios by phytoplankton can vary significantly from region to region.

  3. Phosphorus Deficiency in Ducklins

    Institute of Scientific and Technical Information of China (English)

    CuiHengmin; LuoLingping

    1995-01-01

    20 one-day-old Tianfu ducklings were fed on a natural diet deficient in phosphorus(Ca 0.80%,P 0.366%)for three weeks and examined for signs and lesions.Signs began to appear at the age of one week,and became serous at two weeks.13 ducklings died during the experiment.Morbidity was 100% and mortality was 65%.The affected ducklings mainly showed leg weakness,severe lamencess,deprssion,lack of appetite and stunted growth,The serum alkaline phosphatase activities increased markedly.The serum phosphorus concentration,tibial ash,ash calcium and phosphorus content decreased obviously.At necropsy,maxillae and ribe were soft,and the latter was crooked.Long ones were soft and broke easily.The hypertrophic zone of the growth-plate in the epiphysis of long ones was lengthened and osteoid tissue increased in the metaphyseal spongiosa histopathologically.The above mentioned symptoms and lesions could be prevented by adding phosphorus to the natural deficient diet(up to 0.65%),The relationship between lesions and signs,pathomorphological characterisation and pathogensis were also discussed in this paper.

  4. Effects of carbon-to-sulfur (C/S) ratio and nitrate (N) dosage on Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorus Removal (DS-EBPR)

    OpenAIRE

    Mei Yu; Hui Lu; Di Wu; Qing Zhao; Fangang Meng; Yudan Wang; Xiaodi Hao; Guang-Hao Chen

    2016-01-01

    In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the role of wastewater compositions in DS-EBPR performance. The optimal specific P release and uptake rates (0.4 and 2.4 mg P/g VSS/h, respectively) were ...

  5. Effects of carbon-to-sulfur (C/S) ratio and nitrate (N) dosage on Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorus Removal (DS-EBPR)

    Science.gov (United States)

    Yu, Mei; Lu, Hui; Wu, Di; Zhao, Qing; Meng, Fangang; Wang, Yudan; Hao, Xiaodi; Chen, Guang-Hao

    2016-03-01

    In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the role of wastewater compositions in DS-EBPR performance. The optimal specific P release and uptake rates (0.4 and 2.4 mg P/g VSS/h, respectively) were achieved at C/S/P/N mass ratio of 150/200/20/20, and poly-S is supplied as a potential electron and energy storage. The nitrate dosage in a range of 10–50 mg N/L had no significant influence on P uptake rates (2.1 ~ 2.4 mg P/g VSS/h), but significantly affected the storage of inclusion poly-S, the poly-S oxidation rate was increased about 16% while dosing nitrate from 20 to 30 mg N/L. It implies that nitrate is denitrified in the P uptake phase, and excess nitrate is further consumed by poly-S. Moreover, the microbial analysis showed that the functional bacteria should mostly belong to denitrifying bacteria or Unclassified genera.

  6. Effects of carbon-to-sulfur (C/S) ratio and nitrate (N) dosage on Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorus Removal (DS-EBPR).

    Science.gov (United States)

    Yu, Mei; Lu, Hui; Wu, Di; Zhao, Qing; Meng, Fangang; Wang, Yudan; Hao, Xiaodi; Chen, Guang-Hao

    2016-01-01

    In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the role of wastewater compositions in DS-EBPR performance. The optimal specific P release and uptake rates (0.4 and 2.4 mg P/g VSS/h, respectively) were achieved at C/S/P/N mass ratio of 150/200/20/20, and poly-S is supplied as a potential electron and energy storage. The nitrate dosage in a range of 10-50 mg N/L had no significant influence on P uptake rates (2.1 ~ 2.4 mg P/g VSS/h), but significantly affected the storage of inclusion poly-S, the poly-S oxidation rate was increased about 16% while dosing nitrate from 20 to 30 mg N/L. It implies that nitrate is denitrified in the P uptake phase, and excess nitrate is further consumed by poly-S. Moreover, the microbial analysis showed that the functional bacteria should mostly belong to denitrifying bacteria or Unclassified genera. PMID:26983801

  7. 强化生物除磷系统的微生物学及生化特性研究进展%Review on the Microbiological and Biochemical Characteristics of Enhanced Biological Phosphorus Removal System

    Institute of Scientific and Technical Information of China (English)

    徐立杰; 郭春艳; 彭永臻; 袁志国

    2011-01-01

    综述了强化生物除磷(Enhanced biological phosphorus removal,EBPR)系统的微生物学和生化特性两方面的最新研究进展.在微生物学方面,归纳了EBPR系统中的主要微生物--聚磷菌、聚糖菌、反硝化聚磷菌的分类及相互之间的竞争和联系.具有聚磷功能的微生物种类繁多,目前普遍认为Accumulibacter是一种典型的聚磷菌,在各种规模的EBPR系统中均不同程度的存在.关于聚磷菌和聚糖菌的联系、反硝化聚磷菌的分类问题存在争论.在生化特性方面,归纳了聚磷菌体内三大聚合物--糖原、聚β-羟基烷酸脂和聚合磷酸盐与聚磷菌代谢功能的关系.聚磷菌厌氧阶段的还原力由糖酵解和有机底物TCA循环共同提供,其比例受种群结构和实验条件影响.糖原根据不同菌株厌氧阶段的降解途径有所不同,但是对细胞都起到调节氧化平衡的作用.聚β-羟基烷酸脂的组成由有机底物决定,丙酸为底物时4种单体均可检测出来.聚磷菌厌氧释磷的能量来自聚磷分解和糖原分解,耗能受环境条件影响.图5表3参37%The microbiological and biochemical characteristics of enhanced biological phosphorus removal (EBPR) process was summarized. With respect to the microbiology, the competition and relationship among the main microbes in the system, including poly-phosphate accumulating organisms (PAOs), glycogen accumulating organisms (GAOs) and denitrified PAOs (DPAOs) were concluded. A wide variety of PAOs were separated from the EBPR system and the Accumulibacter was considered a typical PAO, existing in all kinds of EBPR systems. There was still controversy concerning the relationship between PAOs and GAOs and the classification of DPAOs. With respect to the biochemistry, the relevance between the intracellular polymers and the metabolic function was concluded. The reducing power in the anaerobic phase was provided both by the TCA circulation and the glycolysis process

  8. Sustainable Phosphorus Measures: Strategies and Technologies for Achieving Phosphorus Security

    OpenAIRE

    Stuart White; Dana Cordell

    2013-01-01

    Phosphorus underpins the world’s food systems by ensuring soil fertility, maximising crop yields, supporting farmer livelihoods and ultimately food security. Yet increasing concerns around long-term availability and accessibility of the world’s main source of phosphorus—phosphate rock, means there is a need to investigate sustainable measures to buffer the world’s food systems against the long and short-term impacts of global phosphorus scarcity. While the timeline of phosphorus scarcity is c...

  9. Phosphorus in prebiotic chemistry

    OpenAIRE

    Schwartz, Alan W

    2006-01-01

    The prebiotic synthesis of phosphorus-containing compounds—such as nucleotides and polynucleotides—would require both a geologically plausible source of the element and pathways for its incorporation into chemical systems on the primitive Earth. The mineral apatite, which is the only significant source of phosphate on Earth, has long been thought to be problematical in this respect due to its low solubility and reactivity. However, in the last decade or so, at least two pathways have been dem...

  10. Characterization and sonochemical synthesis of black phosphorus from red phosphorus

    Science.gov (United States)

    Aldave, Sandra H.; Yogeesh, Maruthi N.; Zhu, Weinan; Kim, Joonseok; Sonde, Sushant S.; Nayak, Avinash P.; Akinwande, Deji

    2016-03-01

    Phosphorene is a new two-dimensional material which is commonly prepared by exfoliation from black phosphorus bulk crystals that historically have been synthesized from white phosphorus under high-pressure conditions. The few layers of phosphorene have a direct band gap in the range of 0.3-2 eV and high mobility at room temperature comparable to epitaxial graphene. These characteristics can be used for the design of high speed digital circuits, radio frequency circuits, flexible and printed systems, and optoelectronic devices. In this work, we synthesized black phosphorus from red phosphorus, which is a safer solid precursor, using sonochemistry. Furthermore, via a variety of microscopy and spectroscopy techniques, we report characterization results of the sonochemically synthesized black phosphorus in addition to the commercial black phosphorus. Finally, we describe the air stability of black phosphors and the crystalline structure of the synthesized material. This is the first result of sonochemical or solution-based synthesis of black phosphorus based on readily available low-cost red phosphorus. This solution-based synthesis of black phosphorus is suitable for printable applications of nanomaterial.

  11. Sustainable Phosphorus Measures: Strategies and Technologies for Achieving Phosphorus Security

    Directory of Open Access Journals (Sweden)

    Stuart White

    2013-01-01

    Full Text Available Phosphorus underpins the world’s food systems by ensuring soil fertility, maximising crop yields, supporting farmer livelihoods and ultimately food security. Yet increasing concerns around long-term availability and accessibility of the world’s main source of phosphorus—phosphate rock, means there is a need to investigate sustainable measures to buffer the world’s food systems against the long and short-term impacts of global phosphorus scarcity. While the timeline of phosphorus scarcity is contested, there is consensus that more efficient use and recycling of phosphorus is required. While the agricultural sector will be crucial in achieving this, sustainable phosphorus measures in sectors upstream and downstream of agriculture from mine to fork will also need to be addressed. This paper presents a comprehensive classification of all potential phosphorus supply- and demand-side measures to meet long-term phosphorus needs for food production. Examples range from increasing efficiency in the agricultural and mining sector, to technologies for recovering phosphorus from urine and food waste. Such measures are often undertaken in isolation from one another rather than linked in an integrated strategy. This integrated approach will enable scientists and policy-makers to take a systematic approach when identifying potential sustainable phosphorus measures. If a systematic approach is not taken, there is a risk of inappropriate investment in research and implementation of technologies and that will not ultimately ensure sufficient access to phosphorus to produce food in the future. The paper concludes by introducing a framework to assess and compare sustainable phosphorus measures and to determine the least cost options in a given context.

  12. [Effects of soil phosphorus level on morphological and photosynthetic characteristics of Ageratina adenophora and chromolaena odorata].

    Science.gov (United States)

    Wang, Manlia; Feng, Yulong; Li, Xin

    2006-04-01

    In this paper, a comparative study was made on the growth, morphology, biomass allocation, and photosynthesis of two invasive plant species Ageratina adenophora and Chromolaena odorata under five soil phosphorus levels, aimed to know how the test plant species acclimate to the changes of soil phosphorus level, evaluate which plant traits were associated with the invasiveness of the two species, and know whether the increased level of soil phosphorus could facilitate their invasion. The results showed that the two species had considerable phenotypic plasticity and ? phosphorus acclimation ability. At low phosphorus levels, their root mass ratio increased, which could enhance the nutrient capture ability, while at high phosphorus levels, their specific leaf area, maximum net photosynthetic rate, light saturation point, and chlorophyll and carotenoid contents per unit area were high, and the assimilative capacity and area increased, which could facilitate their carbon gain. A. adenophora had higher phosphorus acclimation ability than C. odorata. With the increase of phosphorous level, the relative growth rate, total biomass, branch number, leaf area index, and maximum net photosynthetic rate of the two species increased significantly, and most of the parameters were not decreased significantly under over-optimal phosphorus level. The two species could grow better under high phosphorus levels which were usually excessive and/or harmful for most native species, and enhanced soil phosphorus level might promote their invasion. At high phosphorus levels, the two invasive plant species might shade out native species through increasing their plant height, branch number, and leaf area index. The two species could maintain relatively high growth rate under high phosphorus levels in dry season when native plant species almost stopped growing. The ability that the invasive plant species could temporally use natural resources which native plant species could not use was also

  13. PHOSPHORUS REMOVAL USING STEEL SLAG

    Institute of Scientific and Technical Information of China (English)

    Y.Z. Lan; S. Zhang; J.K. Wang; R. W. Smith

    2006-01-01

    Steel slag is a byproduct produced in large amounts in the steel-making process. It is an important resource that can be effectively utilized. An experiment was described in which steel slag was tested as an adsorbent for the removal of phosphorus from waste water. Phosphorus removal depended on the amount of steel slag added, the pH value, the contact time, and the initial concentration. Under laboratory conditions when the added slag was 7.5g/L, the contact time 2h, and the pH value was equivalent to 6.5, over 99% of the phosphorus was removed; the experimental data on steel slag adsorption of phosphorus in the water fitted the Freundlich isotherm model. Steel slag was found to be very effective in adsorbing phosphorus.

  14. 太阳辐射减弱和O3增加对冬小麦植株磷含量、分配和转运的影响%Effects of Reduced Solar Irradiance and Enhanced O3 on Phosphorus Concentration, Distribution and Translocation of Winter Wheat Plant

    Institute of Scientific and Technical Information of China (English)

    郑有飞; 李萍; 吴芳芳; 吴荣军; 姚娟

    2012-01-01

    and spike but increased in leaf and stem (in late growth periods) , the total output ( P < 0. 01 ) and phosphorus transfer rate ( P < 0. 05 ) of nutritorium were both decreased significantly, compared to natural background. (2) Phosphorus concentration in root, stem, leaf (in late growth stages) and spike were promoted respectively under 100nL ·L-1 ozone stress(T) , phosphorus distribution rate of milking ripe and mature stages in root and spike were reduced, but in stem and leaf were increased in the mature stage, phosphorus transfer in root, stem, leaf and nutritorium were debase very significantly ( P < 0. 01) , while phosphorus transfer rate in leaf and nutritorium were increased. (3 ) Winter wheat suffered in shadow cooperate enhanced ozone condition, I. E. 100nL ·l-1 +20% (TS1) , 100nL ·L-1 +40% (TS2) and 100nL·L-1 +60% (TS3) , phosphorus concentration were improved in root, stem, leaf and spike organ, phosphorus transfer volume in root, stem, leaf and nutritorium were decreased very significantly ( P < 0. 01 ) , phosphorus distribution rate in spike organ and root( during booting and heading stage) ( P < 0. 05 ) were drop, but in stem and leaf were go up in filling to mature stages ( P < 0. 05 ) . With the shadow intensity increased, the effects on phosphorus distribution rate in stem and spike showed growth trend, and the reduced solar irradiation and enhanced ozone showed synergy during milking ripe stage and mature stages.

  15. Synchronous Upgrading Iron and Phosphorus Removal from High Phosphorus Oolitic Hematite Ore by High Temperature Flash Reduction

    Directory of Open Access Journals (Sweden)

    Deqing Zhu

    2016-05-01

    Full Text Available In this paper, an effective method was developed to remove phosphorus and upgrade iron from high phosphorus oolitic hematite ore by high temperature flash reduction—a wet magnetic separation process. A thermodynamic analysis of iron and phosphorus mineral reactions and experiments with Fe-P separation process were performed, and the mechanism of phosphorus removal and beneficiation of iron is discussed as well. The results show that under the proper conditions, a final metallic iron powder assaying over 91% Fe and 0.25% P was obtained with iron recovery of 90% and phosphorus removal rate of 91.79% using the new process, indicating that the high temperature flash reduction process is a feasible and efficient way to process this kind of complex and refractory iron ore. Moreover, sodium sulfate is found to be capable of improving the removal of phosphorus and the upgrading of iron, as well as enhancing the growth of metallic iron grains significantly for higher recovery of iron.

  16. Functional bacteria and process metabolism of the Denitrifying Sulfur conversion-associated Enhanced Biological Phosphorus Removal (DS-EBPR) system: An investigation by operating the system from deterioration to restoration.

    Science.gov (United States)

    Guo, Gang; Wu, Di; Hao, Tianwei; Mackey, Hamish Robert; Wei, Li; Wang, Haiguang; Chen, Guanghao

    2016-05-15

    A sulfur conversion-associated Enhanced Biological Phosphorus (P) Removal (EBPR) system is being developed to cater for the increasing needs to treat saline/brackish wastewater resulting from seawater intrusion into groundwater and sewers and frequent use of sulfate coagulants during drinking water treatment, as well as to meet the demand for eutrophication control in warm climate regions. However, the major functional bacteria and metabolism in this emerging biological nutrient removal system are still poorly understood. This study was thus designed to explore the functional microbes and metabolism in this new EBPR system by manipulating the deterioration, failure and restoration of a lab-scale system. This was achieved by changing the mixed liquor suspended solids (MLSS) concentration to monitor and evaluate the relationships among sulfur conversion (including sulfate reduction and sulfate production), P removal, variation in microbial community structures, and stoichiometric parameters. The results show that the stable Denitrifying Sulfur conversion-associated EBPR (DS-EBPR) system was enriched by sulfate-reducing bacteria (SRB) and sulfide-oxidizing bacteria (SOB). These bacteria synergistically participated in this new EBPR process, thereby inducing an appropriate level of sulfur conversion crucial for achieving a stable DS-EBPR performance, i.e. maintaining sulfur conversion intensity at 15-40 mg S/L, corresponding to an optimal sludge concentration of 6.5 g/L. This range of sulfur conversion favors microbial community competition and various energy flows from internal polymers (i.e. polysulfide or elemental sulfur (poly-S(2-)/S(0)) and poly-β-hydroxyalkanoates (PHA)) for P removal. If this range was exceeded, the system might deteriorate or even fail due to enrichment of glycogen-accumulating organisms (GAOs). Four methods of restoring the failed system were investigated: increasing the sludge concentration, lowering the salinity or doubling the COD

  17. EXPERIMENTAL STUDY ON ENHANCED REMOVAL OF PHOSPHORUS FROM EFFLUENTS IN MUNICIPAL WASTEWATER TREATMENT PLANT BY CHEMICAL PRECIPITATION%城镇污水处理厂尾水深度化学除磷试验研究

    Institute of Scientific and Technical Information of China (English)

    潘理黎; 王玲; 郑海军; 吕伯昇; 徐伟勇

    2011-01-01

    以位于太湖流域的某城市污水处理厂A/O处理工艺的尾水为对象,进行了化学混凝除磷试验.结果表明,无机高分子混凝剂PFS和PAC较其他无机低分子混凝剂具有更好的除磷效果,且铁系混凝剂比铝系混凝剂除磷效果要好,PFS的除磷效果最好,PAC次之;混凝剂投加量为15 mg·L-1时,可使处理后出水TP的质量浓度<0.5 mg·L-1,混凝剂PFS当n(Fe3+)/n(P)为1.25时除磷效果最好,是一种高效的混凝剂,投加量少、成本低;混凝剂和助凝剂联用时,非离子型PAM对PAC和三氯化铁的助凝效果较明显.降低城镇污水处理厂尾水中磷含量,化学除磷方法是一种有效、可行的选择.%The removal of Phosphorus by chemical coagulation was carried out for the A/O treatment water in a municipal sewage treatment plant situated in the Tathu Lake Basin .The results showed that inorganic macromolecules coagulant PFS and PAC had a better effect on phosphorus removal compared with other inorganic molecules coagulants. And phosphorus removal effect of iron-based coagulants was better than aluminum-salt coagulants.Among the coagulants, phosphorus removal efficiency of PFS was best, PAC took the second place. When the coagulant dosage was 15 mg· L-1, the treated wastewater TP was less than 0.5 mg·L-1. PFS and phosphorus molar ratio (as n(Fe3+)/n(P)) was 1.25. PFS was an efficient coagulant with low dosage and Iow cost. When coagulant combined with flocculant, coagulation aid action of the non-ionic PAM for PAC and ferric chloride coagulant was obviously.Chemical phosphorus removal process can be a simple and effective method to reduce the phosphorus content of the end of the water in urban sewage treatment plants.

  18. Performance of biological phosphorus removal and characteristics of microbial community in the oxic-settling-anaerobic process by FISH analysis

    Institute of Scientific and Technical Information of China (English)

    Jian-fang WANG; Qing-liang ZHAO; Wen-biao JIN; Shi-jie YOU; Jin-na ZHANG

    2008-01-01

    Performance of biological phosphorus removal in the oxic-settling-anaerobic (OSA) process was investigated. Cell staining and fluorescent in situ hybridization (FISH) were used to analyze characteristics and microbial community of sludge.Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system, biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus (TP) contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms (PAOs). FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system, which accounted for around 28% of total bacteria.

  19. Total Value of Phosphorus Recovery.

    Science.gov (United States)

    Mayer, Brooke K; Baker, Lawrence A; Boyer, Treavor H; Drechsel, Pay; Gifford, Mac; Hanjra, Munir A; Parameswaran, Prathap; Stoltzfus, Jared; Westerhoff, Paul; Rittmann, Bruce E

    2016-07-01

    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies. PMID:27214029

  20. Prebiotic phosphorus chemistry reconsidered

    Science.gov (United States)

    Schwartz, A. W.; Orgel, L. E. (Principal Investigator)

    1997-01-01

    The available evidence indicates that the origin of life on Earth certainly occurred earlier than 3.5 billion years ago and perhaps substantially earlier. The time available for the chemical evolution which must have preceded this event is more difficult to estimate. Both endogenic and exogenic contributions to chemical evolution have been considered; i.e., from chemical reactions in a primitive atmosphere, or by introduction in the interiors of comets and/or meteorites. It is argued, however, that the phosphorus chemistry of Earth's earliest hydrosphere, whether primarily exogenic or endogenic in origin, was most likely dominated by compounds less oxidized than phosphoric acid and its esters. A scenario is presented for the early production of a suite of reactive phosphonic acid derivatives, the properties of which may have foreshadowed the later appearance of biophosphates.

  1. Electric Conductivity of Phosphorus Nanowires

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Xiang; LI Hui; ZHANG Xue-Qing; LIEW Kim-Meow

    2009-01-01

    We present the structures and electrical transport properties of nanowires made from different strands of phosphorus chains encapsulated in carbon nanotubes. Optimized by density function theory, our results indicate that the conductance spectra reveal an oscillation dependence on the size of wires. It can be seen from the density of states and current-voltage curves that the structure of nanowires affects their properties greatly. Among them,the DNA-like double-helical phosphorus nanowire exhibits the distinct characteristic of an approximately linear I - V relationship and has a higher conductance than others. The transport properties of phosphorus nanowires are highly correlated with their microstructures.

  2. Phosphorus removal mechanisms at the Yellow River Sweetwater Creek Water Reclamation Facility, Gwinnett County, Georgia. Master's thesis

    Energy Technology Data Exchange (ETDEWEB)

    Borowy, J.T.

    1994-01-01

    This research investigated the capabilities of the Yellow River Sweetwater Creek Water Reclamation Facility in Gwinnett County, GA. to remove phosphorus biologically. Phosphorus levels and removal locations were analyzed in plant operational units (sampling events), while in reactor experiments (pilot studies), waste was subjected to various conditions to promote-biological phosphorus release and uptake. Analysis of plant conditions at the time of experimentation indicates that one-half of the plant phosphorus removal is accomplished biologically through incorporation of phosphorus in microbial cells during growth. It does not appear, however, that enhanced biological phosphorus removal (BPR) is possible due to wastestream characteristics and/or microbial population. It was noted that the basic anaerobic-aerobic sequence associated with enhanced BPR appears to be occurring with the secondary clarifier sludge blanket and return to compartment A of the nitrification basin.

  3. Black Phosphorus based One-dimensional Photonic Crystals and Microcavities

    CERN Document Server

    Kriegel, I

    2016-01-01

    The latest achievements in the fabrication of black phosphorus thin layers, towards the technological breakthrough of a phosphorene atomically thin layer, are paving the way for a their employment in electronics, optics, and optoelectronics. In this work, we have simulated the optical properties of one-dimensional photonic structures, i.e. photonic crystals and microcavities, in which few-layer black phosphorus is one of the components. The insertion of the 5 nm black phosphorous layers leads to a photonic band gap in the photonic crystals and a cavity mode in the microcavity interesting for light manipulation and emission enhancement.

  4. Total Phosphorus in Surface Water

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALP is reported in kilograms/hectare/year. More information about these resources, including the...

  5. Phosphorus application strategies in potato

    OpenAIRE

    Ekelöf, Joakim

    2014-01-01

    Phosphorus (P) is an essential element that plays an important role in carbohydrate metabolism and energy transfer systems in all plants. Sufficient P supply is therefore essential for providing adequate food, fibre and fuel for society. In potato, P deficiency reduces yield and tuber number due to reduced radiation interception by the canopy. Phosphorus is a limited, non-renewable resource. When lost to water bodies, P causes environmental problems such as eutrophication. Potato fields ...

  6. Negative Compressibility in Graphene-terminated Black Phosphorus Heterostructures

    OpenAIRE

    Wu, Yingying; Chen, Xiaolong; Wu, Zefei; Xu, Shuigang; Han, Tianyi; Lin, Jiangxiazi; Cai, Yuan; He, Yuheng; Cheng, Chun; Wang, Ning

    2015-01-01

    Negative compressibility generated by many-body effects in 2D electronic systems can enhance gate capacitance. We observe capacitance enhancement in a newly emerged 2D layered material, atomically thin black phosphorus (BP). The encapsulation of BP by hexagonal boron nitride sheets with few-layer graphene as a terminal ensures ultraclean heterostructure interfaces, allowing us to observe negative compressibility at low hole carrier concentrations. We explained the negative compressibility bas...

  7. A Substance Flow Model for Global Phosphorus

    Science.gov (United States)

    Vaccari, D. A.

    2015-12-01

    A system-based substance flow model (SFM) for phosphorus is developed based on the global phosphorus substance flow analysis (SFA) of Cordell et al (2009). The model is based strictly on mass balance considerations. It predicts the sensitivity of phosphorus consumption to various interventions intended to conserve reserves, as well as interactions among these efforts, allowing a comparison of their impacts on phosphorus demand. The interventions include control of phosphorus losses from soil erosion, food production and food waste, or phosphorus recycling such as from animal manure or human waste.

  8. Anoxic phosphorus removal in a pilot scale anaerobic-anoxic oxidation ditch process

    Institute of Scientific and Technical Information of China (English)

    Hongxun HOU; Shuying WANG; Yongzhen PENG; Zhiguo YUAN; Fangfang YIN; Wang GAN

    2009-01-01

    The anaerobic-anoxic oxidation ditch (A2/O OD) process is popularly used to eliminate nutrients from domestic wastewater. In order to identify the existence of denitrifying phosphorus removing bacteria (DPB), evalu-ate the contribution of DPB to biological nutrient removal,and enhance the denitrifying phosphorus removal in the A2/O OD process, a pilot-scale A2/O OD plant (375 L)was conducted. At the same time batch tests using sequence batch reactors (12 L and 4 L) were operated to reveal the significance of anoxic phosphorus removal. The results indicated that: The average removal efficiency of COD, NH4+, pO3-4, and TN were 88.2%, 92.6%, 87.8%,and 73.1%, respectively, when the steady state of the pilotscale A2/O OD plant was reached during 31-73d,demonstrating a good denitrifying phosphorus removal performance. Phosphorus uptake took place in the anoxic zone by poly-phosphorus accumulating organisms NO2- could be used as electron receptors in denitrifying phosphorus removal, and the phosphorus uptake rate with NO2- as the electron receptor was higher than that with NO3- when the initial concentration of either NO2- or NO3 was 40 mg/L.

  9. Remove and recover phosphorus during anaerobic digestion of excess sludge by adding waste iron scrap

    Directory of Open Access Journals (Sweden)

    Zheng Wei

    2013-01-01

    Full Text Available In the current investigation, the feasibility of phosphorus removal in the anaerobic digestion of excess sludge by adding waste iron scrap (WIS was studied. The results show that the removal efficiency of phosphorus increases with the amount of WIS, and the maximum removal efficiency could reach 39%, 93% and 99% at WIS dosages of 1, 2 and 3 g/L, respectively. Sterilization greatly decreases the removal efficiency of phosphorus, having only -6%, 53% and 64% at WIS dosages of 1, 2 and 3 g/L, respectively. This means that iron-reducing bacteria and hydrolytic bacteria enhance 45%, 40% and 35% of phosphorus removal at WIS dosages of 1, 2 and 3 g/L, respectively. The first and the most important mechanism of phosphorus removal using WIS is hydrolytic bacteria, which reduce the pH of sludge to corrode the WIS, followed by precipitation of phosphorus by ferrous iron generated from the iron-reducing bacteria. Phosphorus adsorption onto the WIS is the second probable mechanism. The removed phosphorus is recovered up to 56% using magnet. This method is characterized by high removal efficiency, easy and steady operation, low cost, recovery and reuse, making it better than other physical and chemical treatments.

  10. Evaporation Behavior of Phosphorus from Metallurgical Grade Silicon via Calcium-Based Slag Treatment and Hydrochloric Acid Leaching

    Science.gov (United States)

    Huang, Liuqing; Lai, Huixian; Lu, Chenghao; Fang, Ming; Ma, Wenhui; Xing, Pengfei; Luo, Xuetao; Li, Jintang

    2016-01-01

    Phosphorus removal from metallurgical grade silicon by CaO-SiO2-CaCl2 slag treatment, HCl leaching, and vacuum refining was investigated. The effect of different compositions of slag was evaluated. The calcium concentration in slag-treated silicon increased with increasing CaO/SiO2 mass ratio of slag, decreasing the evaporation efficiency of phosphorus in molten silicon. The total phosphorus removal efficiency changed from 93.0% to 98.3% when the slag-treated silicon was treated with HCl before vacuum refining. The final concentration of phosphorus in silicon was 0.43 ppmw. This is because phosphorus was removed from metallurgical-grade silicon as follows: Phosphorus reacts with slag at the silicon/slag interface and forms Ca3(PO4)2 and Ca3P2, most of which diffuse from the interface to the slag phase. The remaining Ca3(PO4)2 and Ca3P2 reduce the phosphorus removal efficiency by altering the activity coefficient of phosphorus in molten silicon. HCl leaching enhanced the phosphorus removal efficiency by removing the remaining Ca3(PO4)2 and Ca3P2. Therefore, the mass transfer of phosphorus from metallurgical-grade silicon was accelerated.

  11. Study on biological phosphorus removal process by Acinetobacter lwoffi: possibility to by-pass the anaerobic phase

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, R.; Lodi, A.; Rovatti, M. [Institute of Chemical and Process Engineering ``G.B. Bonino``, University of Genoa (Italy)

    1998-03-01

    An Acinetobacter lwoffi culture has been submitted to anaerobic/aerobic conditions in a Sequencing Batch Reactor (SBR) in order to study the ability of this strain in biological phosphorus removal process. Even by feeding a pure sodium acetate substrate, no phosphorus release has been detected during anaerobiosis, while phosphorus uptake beyond metabolic needs has been recorded during the aerobic phase; the anaerobic phase seems to have no influence on the enhanced biological phosphorus removal mechanisms. Hence aerobic batch tests have been carried out in order to verify the ability of Acinetobacter lwoffi to remove phosphorus by ``luxury uptake`` and ``overplus accumulation`` without anaerobic stress. Obtained results revealed a phosphorus removal efficiency of 75-80%. (orig.) With 5 figs., 3 tabs., 18 refs.

  12. Natural Phosphorus Sources for the Pacific Northwest

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Phosphorus is a naturally occurring element found in all rocks; the amount varies by the type of rock. The amount of phosphorus in sediments is expected to be...

  13. Electric Conductivity of Phosphorus Nanowires

    International Nuclear Information System (INIS)

    We present the structures and electrical transport properties of nanowires made from different strands of phosphorus chains encapsulated in carbon nanotubes. Optimized by density function theory, our results indicate that the conductance spectra reveal an oscillation dependence on the size of wires. It can be seen from the density of states and current-voltage curves that the structure of nanowires affects their properties greatly. Among them, the DNA-like double-helical phosphorus nanowire exhibits the distinct characteristic of an approximately linear I – V relationship and has a higher conductance than others. The transport properties of phosphorus nanowires are highly correlated with their microstructures. (condensed matter: structure, mechanical and thermal properties)

  14. Edge phonons in black phosphorus.

    Science.gov (United States)

    Ribeiro, H B; Villegas, C E P; Bahamon, D A; Muraca, D; Castro Neto, A H; de Souza, E A T; Rocha, A R; Pimenta, M A; de Matos, C J S

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  15. Characteristics of EPS taken from an enhanced biological phosphorus removal system%强化生物除磷系统中胞外聚合物的特性

    Institute of Scientific and Technical Information of China (English)

    王然登; 程战利; 彭永臻; 王淑莹

    2014-01-01

    EPS could act as a reservoir for phosphorus in biological phosphorus removal process. To better understand the physicochemical properties of EPS in the biological phosphorus removal system, two types of EPS taken from the systems that operated complete aerobically with little phosphorus removal ability (R1) and alternative anaerobically/aerobically with excellent phosphorus removal efficiency (R2) were studied. Results showed that protein was predominant in the EPS of R2, while the EPS from R1 was dominated by polysaccharides. Protein-like fluorophores and fulvic acid-like fluorophores were the main EEM spectra in both EPS types, whereas the fluorescence intensity of protein-like substances in R2 was higher than that of R1 at the end of aerobic phase. The content of Ca2+was higher than Mg2+in R1, while it was opposite in R2. Meanwhile, the average value of Ca2+in R1 was 8.67mg/g-MLSS, higher than that of R2 (2.40mg/gMLSS) and the TP contents of R2 (21.65mg/gMLSS) was much higher than that in R1 (13.83mg/gMLSS) at the end of aeration. In addition, the zeta potential of R1 (-35mV) was more negative than that in R2 (-23mV).These results demonstrated that the characteristics of EBPR system was different from the complete-aerobic sludge system.%胞外聚合物(EPS)在生物除磷过程中具有蓄磷能力,为进一步明确生物除磷系统中的EPS特性,以不具有明显除磷能力的全程好氧活性污泥系统(R1)的EPS作为对比,考察了具有良好除磷效果的厌氧/好氧交替下的强化生物除磷系统(R2)中EPS的理化特性.结果表明,相对于R1中的EPS主成分在一个周期内的不固定,R2中的蛋白质含量一直明显高于多糖含量;两者的主要荧光物质均为类蛋白质和类富里酸,但在好氧末期 R2中类蛋白质的荧光强度高于 R1; R1的 EPS 中 Ca2+> Mg2+,而在 R2中, Mg2+>Ca2+,同时 R1中的 Ca2+含量平均值为8.67mg/gMLSS,大于 R2中 Ca2+的平均值2.40mg/gMLSS;在好氧末期,R2中的 TP

  16. Phosphorus stress effects on assimilation of nitrate

    International Nuclear Information System (INIS)

    An experiment was conducted to investigate alterations in uptake and assimilation of NO3- by phosphorus-stressed plants. Young tobacco plants (Nicotiana tabacum [L.], cv NC 2326) growing in solution culture were derived of an external phosphorus (P) supply for 12 days. On selected days, plants were exposed to 15NO3- during the 12 hour light period to determine changes in NO3- assimilation as the P deficiency progressed. Decreased whole-plant growth was evident after 3 days of P deprivation and became more pronounced with time, but root growth was unaffected until after day 6. Uptake of 15NO3- per gram root dry weight and translocation of absorbed 15NO3- out of the root were noticeably restricted in -P plants by day 3, and effects on both increased in severity with time. Whole-plant reduction of 15NO3- and 15N incorporation into insoluble reduced-N in the shoot decreased after day 3. Although the P limitation was associated with a substantial accumulation of amino acids in the shoot, there was no indication of excessive accumulation of soluble reduced-15N in the shoot during the 12 hour 15NO3- exposure periods. The results indicate that alterations in NO3- transport processes in the root system are the primary initial responses limiting synthesis of shoot protein in P-stressed plants. Elevated amino acid levels evidently are associated with enhanced degradation of protein rather than inhibition of concurrent protein synthesis

  17. Ruzigrass affecting soil-phosphorus availability

    Directory of Open Access Journals (Sweden)

    Alexandre Merlin

    2013-12-01

    Full Text Available The objective of this work was to evaluate the effectiveness of ruzigrass (Urochloaruziziensis in enhancing soil-P availability in areas fertilized with soluble or reactive rock phosphates. The area had been cropped for five years under no-till, in a system involving soybean, triticale/black-oat, and pearl millet. Previously to the five-year cultivation period, corrective phosphorus fertilization was applied once on soil surface, at 0.0 and 80 kg ha-1 P2O5, as triple superphosphate or Arad rock phosphate. After this five-year period, plots received the same corrective P fertilization as before and ruzigrass was introduced to the cropping system in the stead of the other cover crops. Soil samples were taken (0-10 cm after ruzigrass cultivation and subjected to soil-P fractionation. Soybean was grown thereafter without P application to seed furrow. Phosphorus availability in plots with ruzigrass was compared to the ones with spontaneous vegetation for two years. Ruzigrass cultivation increased inorganic (resin-extracted and organic (NaHCO3 soil P, as well as P concentration in soybean leaves, regardless of the P source. However, soybean yield did not increase significantly due to ruzigrass introduction to the cropping system. Soil-P availability did not differ between soluble and reactive P sources. Ruzigrass increases soil-P availability, especially where corrective P fertilization is performed.

  18. Phosphorus Accumulating Organisms and Biogeochemical Hotspots

    Science.gov (United States)

    Archibald, J.; Walter, M. T.

    2008-12-01

    Despite extensive research, many of the processes that control phosphorus (P) movement from agricultural fields to streams and lakes are not well understood. This limits our ability to develop management strategies that will mediate P contamination of freshwater ecosystems and subsequent eutrophication. Recent advances in molecular microbiology have prompted a paradigm shift in wastewater treatment that recognizes and exploits the ways specific microbial processes influence P solubility. Central to this enhanced biological phosphorus removal in wastewater treatment plants is a relatively recently discovered microorganism, Candidatus accumulibacter, which takes-up P and stores it internally as polyphosphate under alternating aerobic and anaerobic conditions. Within the past few months we have discovered this organism in the natural environment and its role in P biogeochemistry is unclear. We speculate that it may function similarly in variable source areas, which experience cycles of saturation and desaturation, as it does in the anaerobic- aerobic cycles in a wastewater treatment plant. If so, there may be potential opportunities to realize similarly new perspectives and advancements in the watershed context as have been seen in wastewater technologies. Here we present some of our preliminary findings.

  19. 起始 pH 值对序批式反应器中强化生物除磷系统的影响研究%Effect of Initial pH on Enhanced Biological Phosphorus Removal in Sequencing Batch Reactor (SBR)

    Institute of Scientific and Technical Information of China (English)

    李亚静; 谭静亮

    2013-01-01

    Three laboratory-scale sequencing batch reactors (SBRs) were operated continuously to investigate the influence of wastewater initial pH on enhanced biological phosphorus removal (SBR1: pH=6.5; SBR2: pH=7.0; SBR3: pH=7.5). Re-sults showed that the soluble ortho-phosphorus (SOP) release and uptake were increased, while the pH value was increased. And the SOP removal efficiency of the three reactors reached 82.69%、93.87% and 98.50% respectively. The proportion of phosphorus accumulating bacteria (PAO) in the three SBRs was calculated by FISH technology, namely SBR3 > SBR2 >SBR1, The proportion of PAO increased with the increase of the pH value. In the range of pH 6.5~7.5,the activity of dehy-drogenase increased linearly with pH value,The results indicated that a higher pH value was beneficial to the growth and the activity of PAO,which led to an improved phosphorus removal performance. Thus, the efficiency of enhanced biological phosphorus removal can be significantly improved by controlling the initial pH of wastewater.%  通过3个序批式反应器(SBR)的连续运行,研究了污水不同起始 pH 值对强化生物除磷系统(EBPR)的影响(SBR1:pH=6.5;SBR2:pH=7.0;SBR3:pH=7.5).结果表明:随着 pH 值的提高,厌氧释磷量和好氧吸磷量都逐渐增加,释磷速率和吸磷速率也在增加;除磷效率分别为82.69%、93.87%和98.50%.运用荧光原位杂交技术(FISH)鉴定 EBPR 中的功能菌为聚磷菌(PAO)并计算出其含量,即 SBR3>SBR2>SBR1,得到在一定的 pH 值范围内 pH 值越高聚磷菌的含量越高.比较不同 pH 值下 EBPR 系统中脱氢酶活性的变化规律,在 pH=6.5~7.5范围内,脱氢酶的活性随着 pH 的增加而线性增加,表明较高的 pH 有利于 PAO 的生长和提高 PAO 的活性,从而提高了除磷效率.因此,通过控制污水起始 pH 值的方法可以达到显著提高强化生物除磷效果的目的.

  20. Effect of Initial pH on Enhanced Biological Phosphorus Removal in Sequencing Batch Reactor (SBR)%起始 pH 值对序批式反应器中强化生物除磷系统的影响研究

    Institute of Scientific and Technical Information of China (English)

    李亚静; 谭静亮

    2013-01-01

      通过3个序批式反应器(SBR)的连续运行,研究了污水不同起始 pH 值对强化生物除磷系统(EBPR)的影响(SBR1:pH=6.5;SBR2:pH=7.0;SBR3:pH=7.5).结果表明:随着 pH 值的提高,厌氧释磷量和好氧吸磷量都逐渐增加,释磷速率和吸磷速率也在增加;除磷效率分别为82.69%、93.87%和98.50%.运用荧光原位杂交技术(FISH)鉴定 EBPR 中的功能菌为聚磷菌(PAO)并计算出其含量,即 SBR3>SBR2>SBR1,得到在一定的 pH 值范围内 pH 值越高聚磷菌的含量越高.比较不同 pH 值下 EBPR 系统中脱氢酶活性的变化规律,在 pH=6.5~7.5范围内,脱氢酶的活性随着 pH 的增加而线性增加,表明较高的 pH 有利于 PAO 的生长和提高 PAO 的活性,从而提高了除磷效率.因此,通过控制污水起始 pH 值的方法可以达到显著提高强化生物除磷效果的目的.%Three laboratory-scale sequencing batch reactors (SBRs) were operated continuously to investigate the influence of wastewater initial pH on enhanced biological phosphorus removal (SBR1: pH=6.5; SBR2: pH=7.0; SBR3: pH=7.5). Re-sults showed that the soluble ortho-phosphorus (SOP) release and uptake were increased, while the pH value was increased. And the SOP removal efficiency of the three reactors reached 82.69%、93.87% and 98.50% respectively. The proportion of phosphorus accumulating bacteria (PAO) in the three SBRs was calculated by FISH technology, namely SBR3 > SBR2 >SBR1, The proportion of PAO increased with the increase of the pH value. In the range of pH 6.5~7.5,the activity of dehy-drogenase increased linearly with pH value,The results indicated that a higher pH value was beneficial to the growth and the activity of PAO,which led to an improved phosphorus removal performance. Thus, the efficiency of enhanced biological phosphorus removal can be significantly improved by controlling the initial pH of wastewater.

  1. Full-scale biological phosphorus removal: quantification of storage polymers, microbial performance and metabolic modelling

    OpenAIRE

    Lanham, Ana Alexandra Barbosa

    2012-01-01

    Enhanced biological phosphorus removal (EBPR) can be applied in wastewater treatment plants (WWTPs), as a sustainable and efficient way to remove phosphorus from wastewater and hence reduce its impact on eutrophication. This work characterises the performance, metabolism and identity of the microbial EBPR communities in full-scale WWTPs. The accurate quantification of the internal storage compounds, namely polyhydroxyalkanoate (PHA) and glycogen, is crucial to the characterisat...

  2. Biological removal of phosphorus and nitrogen from wastewater : new insights from metagenomic and metatranscriptomic approaches

    OpenAIRE

    Mao, Yanping; 毛艷萍

    2014-01-01

    The study was conducted to reveal the insights of microbial diversity, functional profile and gene expression of microorganisms responsible for enhanced biological phosphorus removal (EBPR) and hydrogen-oxidizing autotrophic denitrification mainly by using metagenomic and metatranscriptomic analysis based on high-throughput sequencing. Two sequencing batch reactors (SBRs) were operated to remove phosphorus (15 mg/L) from synthetic wastewater. The integrated metagenomic and metatranscripto...

  3. Electrochemical characteristics of phosphorus doped Si-C composite for anode active material of lithium secondary batteries

    Institute of Scientific and Technical Information of China (English)

    Jae-Hyun NOH; Kwan-Young LEE; Joong-Kee LEE

    2009-01-01

    Phosphorus doped silicon-carbon composite particles were synthesized through a DC arc plasma torch. Silane(SiH4) and methane(CH4) were introduced into the reaction chamber as the precursor of silicon and carbon, respectively. Phosphine(PH3) was used as a phosphorus dopant gas. Characterization of synthesized particles were carried out by scanning electron microscopy(SEM), X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS) and bulk resistivity measurement. Electrochemical properties were investigated by cyclic test and electrochemical voltage spectroscopy(EVS). In the experimental range, phosphorus doped silicon-carbon composite electrode exhibits enhanced cycle performance than intrinsic silicon and phosphorus doped silicon. It can be explained that incorporation of carbon into silicon acts as a buffer matrix and phosphorus doping plays an important role to enhance the conductivity of the electrode, which leads to the improvement of the cycle performance of the cell.

  4. Microbial Phosphorus Removal in Waste Stabilisation Pond Wastewater Treatment Systems

    OpenAIRE

    Mbwele, Lydia Ambakisye

    2006-01-01

    Waste Stabilisation Ponds (WSPs) are characterised by low phosphorus (P) removal capacity. Heterotrophic bacteria are principal microbial agents in WSPs in addition to algae. As treatment proceeds in WSPs, algal growth increases and pH rises, this has lead to believe that P removal is mainly through sedimentation as organic P algal biomass and precipitation as inorganic P. In activated sludge treatment plants (AS), microbial P removal has been improved and is termed as enhanced biological pho...

  5. An Investigation of the Biochemistry of Biological Phosphorus Removal

    OpenAIRE

    Erdal, Zeynep Kisoglu

    2002-01-01

    Although enhanced biological phosphorus removal (EBPR) and complete biological nutrient removal (BNR) systems can be operated successfully by experienced operators, the accuracy of design and strength of the scientific background need to be reinforced to enable accurate modeling and economically optimal design. One way to accomplish this would be through a better understanding of the biochemical mechanisms and microbial population dynamics that determine the reliability and efficiency of EBPR...

  6. Struvite precipitation and phosphorus removal using magnesium sacrificial anode.

    Science.gov (United States)

    Kruk, Damian J; Elektorowicz, Maria; Oleszkiewicz, Jan A

    2014-04-01

    Struvite precipitation using magnesium sacrificial anode as the only source of magnesium is presented. High-purity magnesium alloy cast anode was found to be very effective in recovery of high-quality struvite from water solutions and from supernatant of fermented waste activated sludge from a wastewater treatment plant that does not practice enhanced biological phosphorus removal. Struvite purity was strongly dependent on the pH and the electric current density. Optimum pH of the 24 mM phosphorus and 46 mM ammonia solution (1:1.9 P:N ratio) was in the broad range between 7.5 and 9.3, with struvite purity exceeding 90%. Increasing the current density resulted in elevated struvite purity. No upper limits were observed in the studied current range of 0.05-0.2 A. Phosphorus removal rate was proportional to the current density and comparable for tests with water solutions and with the supernatant from fermented sludge. The highest P-removal rate achieved was 4.0 mg PO4-P cm(-2) h(-1) at electric current density of 45 A m(-2). Initial substrate concentrations affected the rate of phosphorus removal. The precipitated struvite accumulated in bulk liquid with significant portions attached to the anode surface from which regular detachment occurred. PMID:24387911

  7. Environmental Phosphorus Recovery Based on Molecular Bioscavengers

    DEFF Research Database (Denmark)

    Gruber, Mathias Felix

    pressure to develop sustainable phosphorus practices as well as new technologies for phosphorus recovery. Nature has spent billions of years refining proteins that interact with phosphates. This has inspired the present work where the overall ambitions are: to facilitate the development of a recovery......Phosphorus is a ubiquitous element of all known life and as such it is found throughout numerous key molecules related to various cellular functions. The supply of phosphorus is tightly linked to global food security, since phosphorus is used to produce agricultural fertilizers, without which it...... would not be possible to feed the world population. Sadly, the current supply of phosphorus is based on the gradual depletion of limited fossil reserves, and some estimates predict that within 15-25 years we will consume more phosphorus than we can produce. There is therefore a strong international...

  8. Kinetic Model of Enhanced Biological Phosphorus Removal with Mixed Acetic and Propionic Acids as Carbon Sources (Ⅰ) : Model Constitution%乙酸/丙酸作为EBPR碳源的动力学模型研究(Ⅰ)——模型的建立

    Institute of Scientific and Technical Information of China (English)

    张超; 陈银广

    2013-01-01

    以活性污泥ASM2模型为基础,采用混合短链脂肪酸(SCFAs)作为基准物质,建立了增强生物除磷系统中聚磷菌和(PAO)的厌氧/好氧动力学模型.模型的显著特点是厌氧代谢过程中的糖原水解、聚羟基烷酸合成、以及聚磷水解速率由SCFAs的速率方程表示,并考虑了厌氧维持对动力学和计量学的影响.模型建立了过程计量学系数矩阵,包括3个溶解性组分、4个颗粒性组分,同时考虑了pH对代谢动力学的影响.最后,在PAO模型的基础上,建立了GAO的动力学模型,该模型包含7个过程,磷的浓度仅对其好氧生长有影响.%Based on activated sludge model No. 2 ( ASM2 ) , the anaerobic/aerobic kinetic model of phosphorus-accumulating organisms ( PAO) was established with mixed short-chain fatty acids (SCFAs) as the base substance in enhanced biological phosphorus removal process. The characteristic of the PAO model was that the anaerobic metabolism rates of glycogen degradation, poly-β-hydroxyalkanoates synthesis and polyphosphate hydrolysis were expressed by SCFAs uptake equation, and the effects of anaerobic maintenance on kinetics and stoichiometry were considered. The PAO kinetic model was composed of 3 soluble components, 4 particulate components and a pH parameter, which constituted the matrix of stoichiometnc coefficients. On the basis of PAO model, the GAO kinetic model was established, which included 7 processes, and phosphorus content influenced the aerobic metabolism only.

  9. Phosphorus Recovery from Ashes of Sewage Sludge

    Energy Technology Data Exchange (ETDEWEB)

    Cornel, Peter; Schaum, Peter

    2003-07-01

    About 90% of the incoming phosphorus load of waste water is eliminated by waste water treatment and transferred into the sewage sludge. Considerable amounts of sewage sludge can not be used agriculturally but are incinerated. Thus the ash from mono sludge incineration plants contains significant amounts of phosphorus (up to 25% P{sub 2}O{sub 5}) and could be used as raw material in fertilizer industry. The ash is hygienically harmless and free of organic substances. The ratio of phosphorus to heavy metals is basically the same as in the sewage sludge. The first step in separating phosphorus from heavy metals is to dissolve phosphorus by extraction. The most promising way seems to be the release of phosphorus with acids or bases. With 1 m sulphuric acid it is possible to release phosphorus completely. By use of acid most of the heavy metals dissolve, too. With caustic soda as solvent, only 30-40% of the phosphorus can be dissolved but the eluate is almost free of heavy metals. The amount of phosphorus which can be released with caustic soda, depends on the applied precipitant (Al or Fe salts) for phosphorus elimination at the waste water treatment. (author)

  10. Black phosphorus nonvolatile transistor memory

    Science.gov (United States)

    Lee, Dain; Choi, Yongsuk; Hwang, Euyheon; Kang, Moon Sung; Lee, Seungwoo; Cho, Jeong Ho

    2016-04-01

    We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles).We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles). Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02078j

  11. Phosphorus doping a semiconductor particle

    Science.gov (United States)

    Stevens, G.D.; Reynolds, J.S.

    1999-07-20

    A method of phosphorus doping a semiconductor particle using ammonium phosphate is disclosed. A p-doped silicon sphere is mixed with a diluted solution of ammonium phosphate having a predetermined concentration. These spheres are dried with the phosphorus then being diffused into the sphere to create either a shallow or deep p-n junction. A good PSG glass layer is formed on the surface of the sphere during the diffusion process. A subsequent segregation anneal process is utilized to strip metal impurities from near the p-n junction into the glass layer. A subsequent HF strip procedure is then utilized to removed the PSG layer. Ammonium phosphate is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirement. 1 fig.

  12. Enhanced biological phosphorus removal under alternating anaerobic and anoxic conditions. Pt. 1. Data from literature and scientific fundamentals; Vermehrte biologische Phosphorelimination durch alternierende anaerob/anoxische Milieubedingungen. T. 1. Literaturuebersicht und naturwissenschaftliche Grundlagen

    Energy Technology Data Exchange (ETDEWEB)

    Sieker, C.A. [Berliner Wasserbetriebe, Berlin (Germany); Hegemann, W. [Technische Univ. Berlin (Germany). Fachgebiet Siedlungswasserwirtschaft

    2000-07-01

    This paper describes the state of research on excess biological phosphorus removal under alternating anaerobic/anoxic conditions. Up to now only a few experimental investigations exist. They show that denitrifying poly-P-organisms can be accumulated under alternating anaerobic/anoxic conditions and that the efficiency of P-uptake under anoxic and aerobic conditions is similar. Further, the existence of denitrifying poly-P-organisms has a positive influence on denitrification. The experimental results and developed models indicate that denitrifying poly-P-organisms need less substrate for denitrification compared to other heterotrophic denitrifying organisms. This should be reason enough to further investigations on anaerobic/anoxic operated bio-P-processes and to support process configurations, which help denitrifying poly-P-organisms to accumulate. (orig.) [German] In diesem Beitrag wird der Stand der Wissenschaft zur biologischen Phosphorelimination unter anaerob/anoxischen Milieubedingungen beschrieben. Bisher existieren erst vereinzelt Untersuchungen zu diesem Themengebiet. Diese zeigen, dass die Effizienz der P-Elimination unter aeroben und anoxischen Bedingungen vergleichbar ist. Ausserdem zeigen sie, das die Existenz denitrifizierender polyP-Organismen einen positiven Einfluss auf die Denitrifikation hat. Die Versuchsergebnisse und die daraus abgeleiteten metabolischen Modelle deuten an, dass polyP-Organismen weniger Substrat fuer die Denitrifikation benoetigen als andere heterotrophe Organismen. Dieses sollte Anlass genug sein, ueber anaerob/anoxische Bio-P-Verfahren nachzudenken und Betriebsweisen zu unterstuetzen, die die Anreicherung von denitrifizierenden polyP-Organismen beguenstigen. (orig.)

  13. Phosphorus recovery by one or two-step technology with use of acids and bases

    Energy Technology Data Exchange (ETDEWEB)

    Stark, Kristina; Hultman, Bengt

    2003-07-01

    The method of using sludge fractionation is considered to be a sustainable solution where the sludge is seen as the raw material from which products are recovered. This paper will present solutions of advanced technology system for a large wastewater treatment plant. Use of enhanced biological phosphorus removal and fractionation of the sludge in two stages is advantageous both with respect to low necessary chemical and energy demands and recovery efficiency. Phosphorous recovery may be based on one- or two-step technology. Experimental studies have shown that it is possible to recover phosphorus from sludge by the combination of supercritical water oxidation process and alkaline leaching. When the concentration of sodium hydroxide is around 1 M, approximate 50 % of total phosphorus is recovered in room temperature. Meanwhile, over 98 % of the soluble phosphorus is recovered from the liquid phase by adding calcium chloride (CaCl{sub 2}). (author)

  14. Possible complication regarding phosphorus removal with a continuous flow biofilm system: Diffusion limitation

    DEFF Research Database (Denmark)

    Falkentoft, C.M.; Arnz, P.; Henze, Mogens;

    2001-01-01

    Diffusion limitation of phosphate possibly constitutes a serious problem regarding the use of a biofilm reactor for enhanced biological phosphorus removal. A lab-scale reactor for simultaneous removal of phosphorus and nitrate was operated in a continuous alternating mode of operation. For a steady......-state operation with excess amounts of carbon source (acetate) during the anaerobic phase, the same amount of phosphate was released during the anaerobic phase as was taken up during the anoxic phase. The measured phosphorus content of the biomass that detached during backwash after an anoxic phase was low, 2.......4 ± 0.4% (equal to 24 ± 4 mg P/g TS). A simplified computer model indicated the reason to be phosphate diffusion limitation and the model revealed a delicate balance between the obtainable phosphorus contents of the biomass and operating parameters, such as backwash interval, biofilm thickness after...

  15. Phene synergism between root hair length and basal root growth angle for phosphorus acquisition.

    Science.gov (United States)

    Miguel, Magalhaes Amade; Postma, Johannes Auke; Lynch, Jonathan Paul

    2015-04-01

    Shallow basal root growth angle (BRGA) increases phosphorus acquisition efficiency by enhancing topsoil foraging because in most soils, phosphorus is concentrated in the topsoil. Root hair length and density (RHL/D) increase phosphorus acquisition by expanding the soil volume subject to phosphorus depletion through diffusion. We hypothesized that shallow BRGA and large RHL/D are synergetic for phosphorus acquisition, meaning that their combined effect is greater than the sum of their individual effects. To evaluate this hypothesis, phosphorus acquisition in the field in Mozambique was compared among recombinant inbred lines of common bean (Phaseolus vulgaris) having four distinct root phenotypes: long root hairs and shallow basal roots, long root hairs and deep basal roots, short root hairs and shallow basal roots, and short root hairs and deep basal roots. The results revealed substantial synergism between BRGA and RHL/D. Compared with short-haired, deep-rooted phenotypes, long root hairs increased shoot biomass under phosphorus stress by 89%, while shallow roots increased shoot biomass by 58%. Genotypes with both long root hairs and shallow roots had 298% greater biomass accumulation than short-haired, deep-rooted phenotypes. Therefore, the utility of shallow basal roots and long root hairs for phosphorus acquisition in combination is twice as large as their additive effects. We conclude that the anatomical phene of long, dense root hairs and the architectural phene of shallower basal root growth are synergetic for phosphorus acquisition. Phene synergism may be common in plant biology and can have substantial importance for plant fitness, as shown here.

  16. IMPROVING PHOSPHORUS NUTRITION OF COTTON

    OpenAIRE

    Walter B. Gordon; Larry Murphy; Pawel Wiatrak

    2014-01-01

    Crop recovery of applied Phosphorus (P) fertilizer can be low, especially during season of low soil temperature, which decreases plant root growth and nutrient uptake. The H2PO4- or HPO4-2 anions readily react with soil cations such as Calcium (Ca), Magnesium (Mg), iron (Fe) and Aluminum (Al) to produce various phosphate compounds of very limited water solubility. Specialty Ferti...

  17. Abiotic and prebiotic phosphorus chemistry

    OpenAIRE

    Micheletti, Gabriele

    2011-01-01

    The chief obstacle to understand the metabolic origin of life or RNA-based life is to identify a plausible mechanism for overcoming the clutter wrought by abiotic chemistry. Probably trough simple abiotic and then prebiotic reactions we could arrive to simple pre-RNA molecules. Here we report a possible preibiotic synthesis for heterocyclic compounds, and a self-assembling process of adenosine phosphates a constituent of RNA. In these processes we use a simple and prebiotic phosphorus cyc...

  18. The Galactic evolution of phosphorus

    CERN Document Server

    Caffau, E; Faraggiana, R; Steffen, M

    2011-01-01

    As a galaxy evolves, its chemical composition changes and the abundance ratios of different elements are powerful probes of the underlying evolutionary processes. Phosphorous is an element whose evolution has remained quite elusive until now, because it is difficult to detect in cool stars. The infrared weak P I lines of the multiplet 1, at 1050-1082 nm, are the most reliable indicators of the presence of phosphorus. The availability of CRIRES at VLT has permitted access to this wavelength range in stellar spectra.We attempt to measure the phosphorus abundance of twenty cool stars in the Galactic disk. The spectra are analysed with one-dimensional model-atmospheres computed in Local Thermodynamic Equilibrium (LTE). The line formation computations are performed assuming LTE. The ratio of phosphorus to iron behaves similarly to sulphur, increasing towards lower metallicity stars. Its ratio with respect to sulphur is roughly constant and slightly larger than solar, [P/S]=0.10+- 0.10. We succeed in taking an impo...

  19. Phytoextraction of excess soil phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Nilesh C. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Starnes, Daniel L. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Sahi, Shivendra V. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States)]. E-mail: shiv.sahi@wku.edu

    2007-03-15

    In the search for a suitable plant to be used in P phytoremediation, several species belonging to legume, vegetable and herb crops were grown in P-enriched soils, and screened for P accumulation potentials. A large variation in P concentrations of different plant species was observed. Some vegetable species such as cucumber (Cucumis sativus) and yellow squash (Cucurbita pepo var. melopepo) were identified as potential P accumulators with >1% (dry weight) P in their shoots. These plants also displayed a satisfactory biomass accumulation while growing on a high concentration of soil P. The elevated activities of phosphomonoesterase and phytase were observed when plants were grown in P-enriched soils, this possibly contributing to high P acquisition in these species. Sunflower plants also demonstrated an increased shoot P accumulation. This study shows that the phytoextraction of phosphorus can be effective using appropriate plant species. - Crop plants such as cucumber, squash and sunflower accumulate phosphorus and thus can be used in the phytoextraction of excess phosphorus from soils.

  20. Negative compressibility in graphene-terminated black phosphorus heterostructures

    Science.gov (United States)

    Wu, Yingying; Chen, Xiaolong; Wu, Zefei; Xu, Shuigang; Han, Tianyi; Lin, Jiangxiazi; Skinner, Brian; Cai, Yuan; He, Yuheng; Cheng, Chun; Wang, Ning

    2016-01-01

    Negative compressibility is a many-body effect wherein strong correlations give rise to an enhanced gate capacitance in two-dimensional (2D) electronic systems. We observe capacitance enhancement in a newly emerged 2D layered material, atomically thin black phosphorus (BP). The encapsulation of BP by hexagonal boron nitride sheets with few-layer graphene as a terminal ensures ultraclean heterostructure interfaces, allowing us to observe negative compressibility at low hole carrier concentrations. We explain the negative compressibility based on the Coulomb correlation among in-plane charges and their image charges in a gate electrode in the framework of Debye screening.

  1. Chromosomal Location of Traits Associated with Wheat Seedling Water and Phosphorus Use Efficiency under Different Water and Phosphorus Stresses

    Directory of Open Access Journals (Sweden)

    Wei-Yi Song

    2009-09-01

    Full Text Available The objective of this study was to locate chromosomes for improving water and phosphorus-deficiency tolerance of wheat at the seedling stage. A set of Chinese Spring- Egyptian Red wheat substitution lines and their parent Chinese Spring (recipient and Egyptian Red (donor cultivars were measured to determine the chromosomal locations of genes controlling water use efficiency (WUE and phosphorus use efficiency (PUE under different water and phosphorus conditions. The results underlined that chromosomes 1A, 7A, 7B, and 3A showed higher leaf water use efficiency (WUEl = Pn/Tr; Pn = photosynthetic rate; Tr = transpiration rate under W-P (Hoagland solution with1/2P, -W-P (Hoagland solution with 1/2P and 10% PEG. Chromosomes 7A, 3D, 2B, 3B, and 4B may carry genes for positive effects on individual plant water use efficiency (WUEp = biomass/TWC; TWC = total water consumption under WP (Hoagland solution, W-P and -W-P treatment. Chromosomes 7A and 7D carry genes for PUE enhancement under WP, -WP (Hoagland solution with 10% PEG and W-P treatment. Chromosome 7A possibly has genes for controlling WUE and PUE simultaneously, which indicates that WUE and PUE may share the same genetic background. Phenotypic and genetic analysis of the investigated traits showed that photosynthetic rate (Pn and transpiration rate (Tr, Tr and WUEl showed significant positive and negative correlations under WP, W-P, -WP and -W-P, W-P, -WP treatments, respectively. Dry mass (DM, WUEP, PUT (phosphorus uptake all showed significant positive correlation under WP, W-P and -WP treatment. PUE and phosphorus uptake (PUT = P uptake per plant showed significant negative correlation under the four treatments. The results might provide useful information for improving WUE and PUE in wheat genetics.

  2. Potential Phosphorus Mobilisation in Peat Soils

    DEFF Research Database (Denmark)

    Forsmann, Ditte M.; Kjærgaard, Charlotte

    2012-01-01

    Re-establishment of wetlands on peat soils containing phosphorus bound to iron(III)-oxides can lead to an undesirable phosphorus loss to the aquatic environment due to the reductive dissolution of iron(III)-oxides. Thus it is important to be able to assess the potential phosphorus mobilisation from...... peat soils before a re-establishment takes place. The potential phosphorus mobilisation from a peat soil depends not only on the geochemical characteristics but also on the redox conditions, the hydrological regime in the area as well as the hydro-physical properties of the soil. The hypothesis...... for this study is (i) the release of phosphorus in peat is controlled by the geochemistry; (ii) the mobilisation of phosphorus is controlled by both geochemistry and hydro-physics of the soil. For this study, 10 Danish riparian lowland areas with peat soil were selected based on their geochemical characteristics...

  3. Optimization of biological phosphorus and ammonia removal in a combined fixed and suspended growth wastewater treatment system: Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    This project was conducted to optimize design and operational criteria for enhanced biological phosphorus removal and nitrification of ammonia in the fixed growth reactor-suspended growth reactor (FGR-SGR) process. The research completed the investigation of optimum hydraulic retention times for biological phosphorus removal in both the unaerated and aerated phases of the suspended growth components of the FGR-SGR system, including an assessment of the possibility of reducing suspended growth aeration requirements by using oxidized forms of nitrogen rather than dissolved oxygen for biological phosphorus uptake; investigated the effects on biological phosphorus removal and nitrification of varying the internal recycle flow rates; and investigated the optimum solids retention time, or the optimum operating mixed liquor suspended solids concentration, in the suspended growth component of the system for biological phosphorus removal and nitrification-denitrification.

  4. The Story of Phosphorus : Sustainability implications of global phosphorus scarcity for food security

    OpenAIRE

    Cordell, Dana

    2010-01-01

    The story of phosphorus began with the search for the philosopher’s stone, and centuries later the critical role of phosphorus in soil fertility and crop growth was highlighted. Eventually, phosphorus was implicated in the global environmental challenge of eutrophication. Now, we are on the brink of yet another emerging chapter in the story: global phosphorus scarcity linked to food security. Through a transdisciplinary and systemic inquiry, this thesis has analyzed, reconceptualized and synt...

  5. Phosphorus removal in aerated stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, R.; Lodi, A.; Rovatti, M. [Inst. of Chemical and Process Engineering ``G.B. Bonino``, Univ. of Genoa (Italy)

    1999-03-01

    The possibility to obtain biological phosphorus removal in strictly aerobic conditions has been investigated. Experiments, carried out in a continuous stirred tank reactor (CSTR), show the feasibility to obtain phosphorus removal without the anaerobic phase. Reactor performance in terms of phosphorus abatement kept always higher then 65% depending on adopted sludge retention time (SRT). In fact increasing SRT from 5 days to 8 days phosphorus removal and reactor performance increase but overcoming this SRT value a decreasing in reactor efficiency was recorded. (orig.) With 6 figs., 3 tabs., 18 refs.

  6. Influence of feeding various phosphorus sources on apparent digestibility of phosphorus in dairy cows

    NARCIS (Netherlands)

    Ekelund, A.; Sporndly, R.; Valk, H.; Murphy, M.

    2003-01-01

    The present investigated differences in the apparent digestibility of phosphorus (ADP) in lactating cows fed various feed materials containing organic forms of phosphorus (P) or a highly available inorganic phosphorus source. Cows milking an average of 36 kg energy corrected milk (ECM) were used in

  7. Towards global phosphorus security: A systems framework for phosphorus recovery and reuse options

    NARCIS (Netherlands)

    Cordell, D.; Rosemarin, A.; Schroder, J.J.; Smit, A.L.

    2011-01-01

    Human intervention in the global phosphorus cycle has mobilised nearly half a billion tonnes of the element from phosphate rock into the hydrosphere over the past half century. The resultant water pollution concerns have been the main driver for sustainable phosphorus use (including phosphorus recov

  8. 系列混合碳源条件下颗粒化EBPR系统茵群结构变化规律研究%A study of microbial diversity of granule-based enhanced biological phosphorus removal systems cultivated with ratiometric propionate and acetate as mixed carbon sources

    Institute of Scientific and Technical Information of China (English)

    蒋涛; 孙培德; 金均

    2012-01-01

    A series of mixed carbon sources with different ratios of propionate and acetate was applied in granule-based enhanced biological phosphorus removal (EBPR) sludge in SBR reactor. Microbial diversity change during the granular process and functional bacteria competition under different carbon sources were studied. Significant microbial diversity change in EBPR system was exhibited during granulation. Uncultured bacteria previously dominated in the system disappeared rapidly, while uncultured rhodocyclaceae bacterium and portions of candidatus competibacter phosphatis, denitrifying bacterium, acinetobacter and uncultured alpha proteobacterium were gradually washed out. Uncultured chlorobi bacterium and uncultured alpha proteobacterium were the primary phosphorus removal bacteria in developed granular EBPR system. The change of bacteria population ofcandidatus competibacterphosphatis and uncultured chlorobi bacterium was evidenced as a result of microbial diversity under different ratios of mixed carbon sources. The population of candidatus competibacter phosphatis increased monotonically with acetate concentration, decreaseing the system phosphorus removal efficiency. Meanwhile, the population of uncultured chlorobi bacterium had a positive correlation with propionate concentration, which maintained good phosphorus removal efficiency of the EBPR system.%在SBR反应器中接种富含聚磷菌的活性污泥,采用一系列不同丙酸/乙酸比例混合的碳源进行EBPR系统污泥的颗粒化培养,并考察了颗粒化进程中的系统菌群结构变化,以及不同混合碳源条件对系统功能菌种竞争的影响.结果表明,污泥颗粒化过程对EBPR系统菌群结构产生了较大的筛选作用.原本在系统中占优势的一类Uncultured bacterium被迅速淘汰;Uncultured Rhodocyclaceae bacterium、部分Candidatus Competibacter phosphatis、部分Denitrifying bacterium、Acinetobacter及部分Uncultured alpha proteobacterium分别逐渐被淘

  9. Phosphorus diffusion in polycrystalline silicon

    Science.gov (United States)

    Losee, D. L.; Lavine, J. P.; Trabka, E. A.; Lee, S.-T.; Jarman, C. M.

    1984-02-01

    The diffusion of phosphorus in crystallized amorphous Si layers was studied with secondary-ion mass spectroscopy. A two-dimensional diffusion model is used to find effective grain (Dg) and grain-boundary (Dgb) diffusion coefficients. This simplified model leads to Dgb ≤ 10Dg, which is significantly lower than what has been deduced from conventional, larger grained polysilicon. Our result is consistent with specific-gravity measurements, which found a significantly lower ``mass defect'' for layers deposited amorphous and subsequently crystallized as compared to initially polycrystalline layers.

  10. Simulating the effects of phosphorus limitation in the Mississippi and Atchafalaya River plumes

    Science.gov (United States)

    Laurent, A.; Fennel, K.; Hu, J.; Hetland, R.

    2012-11-01

    The continental shelf of the northern Gulf of Mexico receives high dissolved inorganic nitrogen and phosphorus loads from the Mississippi and Atchafalaya rivers. The nutrient load results in high primary production in the river plumes and contributes to the development of hypoxia on the Louisiana shelf in summer. While phytoplankton growth is considered to be typically nitrogen-limited in marine waters, phosphorus limitation has been observed in this region during periods of peak river discharge in spring and early summer. Here we investigate the presence, spatio-temporal distribution and implications of phosphorus limitation in the plume region using a circulation model of the northern Gulf of Mexico coupled to a multi-nutrient ecosystem model. Results from a 7-yr simulation (2001-2007) compare well with several sources of observations and suggest that phosphorus limitation develops every year between the Mississippi and Atchafalaya deltas. Model simulations show that phosphorus limitation results in a delay and westward shift of a fraction of river-stimulated primary production. The consequence is a reduced flux of particulate organic matter to the sediment near the Mississippi delta, but slightly enhanced fluxes west of Atchafalaya Bay. Simulations with altered river phosphate concentrations (±50%) show that significant variation in the spatial extent of phosphorus limitation (±40% in July) results from changes in phosphate load.

  11. Simulating the effects of phosphorus limitation in the Mississippi and Atchafalaya River plumes

    Directory of Open Access Journals (Sweden)

    A. Laurent

    2012-05-01

    Full Text Available The continental shelf of the northern Gulf of Mexico receives high dissolved inorganic nitrogen and phosphorus loads from the Mississippi and Atchafalaya rivers. The nutrient load results in high primary production in the river plumes and contributes to the development of hypoxia on the Texas-Louisiana shelf in summer. While phytoplankton growth is considered to be typically nitrogen-limited, phosphorus limitation has been observed in this region during periods of peak river discharge in spring and early summer. Here we investigate the presence, spatio-temporal distribution and implications of phosphorus limitation in the plume region using a circulation model of the northern Gulf of Mexico coupled to a multi-nutrient ecosystem model. Results from a 7 yr simulation (2001–2007 compare well with available observations and suggest that phosphorus limitation develops every year between the Mississippi and Atchafalaya deltas. Model simulations show that phosphorus limitation results in a delay and westward shift of a fraction of river-stimulated primary production. The consequence is a reduced flux of particulate organic matter to the sediment near the Mississippi delta, but enhanced fluxes westward in the Atchafalaya and far-field regions. Two discharge scenarios with altered river phosphate concentrations (±50 % reveal a significant variation (±40 % in July in the spatial extent of phosphorus limitation with changes in phosphate load.

  12. Simulating the effects of phosphorus limitation in the Mississippi and Atchafalaya River plumes

    Directory of Open Access Journals (Sweden)

    A. Laurent

    2012-11-01

    Full Text Available The continental shelf of the northern Gulf of Mexico receives high dissolved inorganic nitrogen and phosphorus loads from the Mississippi and Atchafalaya rivers. The nutrient load results in high primary production in the river plumes and contributes to the development of hypoxia on the Louisiana shelf in summer. While phytoplankton growth is considered to be typically nitrogen-limited in marine waters, phosphorus limitation has been observed in this region during periods of peak river discharge in spring and early summer. Here we investigate the presence, spatio-temporal distribution and implications of phosphorus limitation in the plume region using a circulation model of the northern Gulf of Mexico coupled to a multi-nutrient ecosystem model. Results from a 7-yr simulation (2001–2007 compare well with several sources of observations and suggest that phosphorus limitation develops every year between the Mississippi and Atchafalaya deltas. Model simulations show that phosphorus limitation results in a delay and westward shift of a fraction of river-stimulated primary production. The consequence is a reduced flux of particulate organic matter to the sediment near the Mississippi delta, but slightly enhanced fluxes west of Atchafalaya Bay. Simulations with altered river phosphate concentrations (±50% show that significant variation in the spatial extent of phosphorus limitation (±40% in July results from changes in phosphate load.

  13. Large improvement of phosphorus incorporation efficiency in n-type chemical vapor deposition of diamond

    International Nuclear Information System (INIS)

    Microwave plasma enhanced chemical vapor deposition is a promising way to generate n-type, e.g., phosphorus-doped, diamond layers for the fabrication of electronic components, which can operate at extreme conditions. However, a deeper understanding of the doping process is lacking and low phosphorus incorporation efficiencies are generally observed. In this work, it is shown that systematically changing the internal design of a non-commercial chemical vapor deposition chamber, used to grow diamond layers, leads to a large increase of the phosphorus doping efficiency in diamond, produced in this device, without compromising its electronic properties. Compared to the initial reactor design, the doping efficiency is about 100 times higher, reaching 10%, and for a very broad doping range, the doping efficiency remains highly constant. It is hypothesized that redesigning the deposition chamber generates a higher flow of active phosphorus species towards the substrate, thereby increasing phosphorus incorporation in diamond and reducing deposition of phosphorus species at reactor walls, which additionally reduces undesirable memory effects

  14. Experimental study on phosphorus release from sediments of shallow lake in wave flume

    Institute of Scientific and Technical Information of China (English)

    SUN; Xiaojing; ZHU; Guangwei; LUO; Liancong

    2006-01-01

    Influence of wave on sediment resuspension and nutrients release from sediments, collected from Lake Taihu and Lake Chaohu, was studied in flume experiments. Under strong-wave conditions, concentrations of suspended solids (SS), total phosphorus (TP) and dissolved total phosphorus (DTP) in overlying water were increased significantly following the sediments re-suspension. During the experiments on sediments of Lake Taihu and Lake Chaohu, TP concentrations increased 6 times and 3 times, and DTP concentration increased 100% and 70% more than it in presuspension, respectively. Concentration of soluble reactive phosphorus (SRP) of experiment on sediment of Lake Taihu increased 25%. During the massive sediment suspension, the dissolved phosphorus in pore water and much of the phosphorus adsorbed by the sediment particles were released into overlying water. The phenomena in this wave flume experiment are quite similar to the situation observed in situ of Lake Taihu. The critical wave stresses of sediment re-suspension are nearly equal. The change of concentrations of SS, TP, and SRP was the same as that in situ situation.This study showed that concentrations of TP and SRP in lake water could be increased significantly by wave disturbance. Phosphorus release was significantly enhanced by wave disturbance at the beginning of massive sediment re-suspension, but decreased later.

  15. Sedimentary phosphorus cycling and a phosphorus mass balance for the Green Bay (Lake Michigan) ecosystem

    Science.gov (United States)

    Klump, J.V.; Edgington, D. N.; Sager, P.E.; Robertson, D.M.

    2011-01-01

    The tributaries of Green Bay have long been recognized as major sources of phosphorus in the Lake Michigan basin. The status of Green Bay as a sink or source of phosphorus for Lake Michigan proper has been less well defined. The bay receives nearly 70% of its annual load of phosphorus ( 700 metric tons (t) · year-1) from a single source: the Fox River. Most of this phosphorus is deposited in sediments accumulating at rates that reach 160 mg · cm-2 · year-1 with an average of 20 mg · cm-2 · year-1. The phosphorus content of these sediments varies from 70 µmol · g-1. Deposition is highly focused, with ~70% of the total sediment accumulation and at least 80% of the phosphorus burial occurring within 20% of the surface area of the bay. Diagenetic and stoichiometric models of phosphorus cycling imply that >80% of the phosphorus deposited is permanently buried. External phosphorus loading to the bay is combined with sediment fluxes of phophorus to arrive at a simple phosphorus budget. Green Bay acts as an efficient nutrient trap, with the sediments retaining an estimated 70-90% of the external phosphorus inputs before flowing into Lake Michigan.

  16. Sustainable use of phosphorus: a finite resource.

    Science.gov (United States)

    Scholz, Roland W; Ulrich, Andrea E; Eilittä, Marjatta; Roy, Amit

    2013-09-01

    Phosphorus is an essential element of life and of the modern agricultural system. Today, science, policy, agro-industry and other stakeholder groups are increasingly concerned about the sustainable use of this resource, given the dissipative nature of phosphorus and difficulties in assessing, evaluating, and coping with phosphorus pollution in aquatic and terrestrial systems. We argue that predictions about a forthcoming peak, followed by a quick reduction (i.e., physical phosphate rock scarcity) are unreasoned and stress that access to phosphorus (economic scarcity) is already, and may increasingly become critical, in particular for smallholders farmers in different parts of the world. The paper elaborates on the design, development, goals and cutting-edge contributions of a global transdisciplinary process (i.e. mutual learning between science and society including multiple stakeholders) on the understanding of potential contributions and risks related to the current mode of using phosphorus on multiple scales (Global TraPs). While taking a global and comprehensive view on the whole phosphorus-supply chain, Global TraPs organizes and integrates multiple transdisciplinary case studies to better answer questions which inform sustainable future phosphorus use. Its major goals are to contribute to four issues central to sustainable resource management: i) long-term management of biogeochemical cycles, in particular the challenge of closing the phosphorus cycle, ii) achieving food security, iii) avoiding environmental pollution and iv) sustainability learning on a global level by transdisciplinary processes. PMID:23769630

  17. Energy and phosphorus recovery from black water

    NARCIS (Netherlands)

    Graaff, de M.S.; Temmink, B.G.; Zeeman, G.; Buisman, C.J.N.

    2011-01-01

    Source-separated black water (BW) (toilet water) containing 38% of the organic material and 68% of the phosphorus in the total household waste (water) stream including kitchen waste, is a potential source for energy and phosphorus recovery. The energy recovered, in the form of electricity and heat,

  18. The Research Progress of H+-Pyrophosphatase-Mediated Enhancements on Plant Phosphorus Use%H+焦磷酸酶促进植物磷利用的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨玉梅; 张梦如; 罗著; 刘畅; 龚明; 邹竹荣

    2015-01-01

    植物的生长发育离不开磷这种大量营养元素,但其利用过程中仍旧存在几大主要问题:磷短缺、磷污染以及土壤有效磷含量低,而通过基因工程策略提高植物磷利用效率无疑是最有效的应对解决途径。其中,由植物质子焦磷酸酶(H+-PPase)介导的成效尤为突出,各种H+-PPase过表达转基因植株具有多方面且几乎一致的优异表型(包括耐低磷,耐盐,抗旱等),这可能与H+-PPase不同的细胞定位及其多功能性有关,并且涉及到质膜H+-ATPase的中间作用以及磷/糖的信号调控、代谢和转运。本文着重对H+-PPase与植物磷胁迫的内在关系、促进植物磷利用的研究成效及其可能的作用机理等方面进行综述,以期为H+-PPase在植物抗逆基因工程中发挥更大作用提供理论依据。%Phosphorus (Pi) is an essential macronutrient element for plant growth and development. However, Pi utilization in plants is still of several major limitations such as shortage of Pi reservoir, environmental pollution by soil Pi loss through leaching and runoff, and low content of absorbable Pi in soil. Accordingly, improvement on plant Pi use efficiency, mainly through the strategy of genetic engineering, has been well recognized as the most practical solution. Therein, a remarkable success mediated by plant H+-pyrophosphatase (H+-PPase) has been achieved, with multifarious meliorated traits (e.g. tolerances to salt, drought, and Pi deficiency) prevalently found in numerous transgenic plants. This outperformance is largely linked to the multifunction and different cellular locations of H+-PPase, and also correlated with the intermediate contribution of plasma membrane H+-ATPase, as well as the signalling&metabolism&transport of Pi and sugar. With a particular focus, this review summarized the current studies of H+-PPase on its major aspects such as the intrinsic relation with Pi stress, the facilitation on plant Pi

  19. Phosphorus recycling potential assessment by a biological test applied to wastewater sludge.

    Science.gov (United States)

    Braak, Etienne; Auby, Sarah; Piveteau, Simon; Guilayn, Felipe; Daumer, Marie-Line

    2016-01-01

    Phosphorus (P) recycling as mineral fertilizer from wastewater activated sludge (WAS) depends on the amount that can be dissolved and separated from the organic matter before the final crystallization step. The aim of the biological phosphorus dissolution potential (BPDP) test developed here was to assess the maximum amount of P that could be biologically released from WAS prior that the liquid phase enters the recovery process. It was first developed for sludge combining enhanced biological phosphorus removal and iron chloride. Because carbohydrates are known to induce acidification during the first stage of anaerobic digestion, sucrose was used as a co-substrate. Best results were obtained after 24-48 h, without inoculum, with a sugar/sludge ratio of 0.5 gCOD/gVS and under strict anaerobic conditions. Up to 75% of the total phosphorus in sludge from a wastewater treatment plant combining enhanced biological phosphorus removal and iron chloride phosphorus removal could be dissolved. Finally, the test was applied to assess BPDP from different sludge using alum compounds for P removal. No dissolution was observed when alum polychloride was used and less than 20% when alum sulphate was used. In all the cases, comparison to chemical acidification showed that the biological process was a major contributor to P dissolution. The possibility to crystallize struvite was discussed from the composition of the liquids obtained. The BPDP will be used not only to assess the potential for phosphorus recycling from sludge, but also to study the influence of the co-substrates available for anaerobic digestion of sludge. PMID:26786893

  20. Bronx River bed sediments phosphorus pool and phosphorus compound identification

    Science.gov (United States)

    Wang, J.; Pant, H. K.

    2008-12-01

    Phosphorus (P) transport in the Bronx River degraded water quality, decreased oxygen levels, and resulted in bioaccumulation in sediment potentially resulting in eutrophication, algal blooms and oxygen depletion under certain temperature and pH conditions. The anthropogenic P sources are storm water runoff, raw sewage discharge, fertilizer application in lawn, golf course and New York Botanical Garden; manure from the Bronx zoo; combined sewoverflows (CSO's) from parkway and Hunts Point sewage plant; pollutants from East River. This research was conducted in the urban river system in New York City area, in order to control P source, figure out P transport temporal and spatial variations and the impact on water quality; aimed to regulate P application, sharing data with Bronx River Alliance, EPA, DEP and DEC. The sediment characteristics influence the distribution and bioavailbility of P in the Bronx River. The P sequential extraction gave the quantitative analysis of the P pool, quantifying the inorganic and organic P from the sediments. There were different P pool patterns at the 15 sites, and the substantial amount of inorganic P pool indicated that a large amount P is bioavailable. The 31P- NMR (Nuclear Magnetic Resonance Spectroscopy) technology had been used to identify P species in the 15 sites of the Bronx River, which gave a qualitative analysis on phosphorus transport in the river. The P compounds in the Bronx River bed sediments are mostly glycerophophate (GlyP), nucleoside monophosphates (NMP), polynucleotides (PolyN), and few sites showed the small amount of glucose-6-phosphate (G6P), glycerophosphoethanoamine (GPEA), phosphoenopyruvates (PEP), and inosine monophosphate (IMP). The land use spatial and temporal variations influence local water P levels, P distributions, and P compositions.

  1. Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution

    Science.gov (United States)

    Demars, B. O. L.; Harper, D. M.; Pitt, J.-A.; Slaughter, R.

    2005-06-01

    In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years). In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001), were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The calibrated model explained 79% and 89% of the observed variance before and after phosphorus control, respectively. A split test revealed that predicted TP loads were in good agreement with observed TP loads (r2=0.85), although TP loads were underestimated under high flow conditions. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. This was despite a relatively modest critical discharge (Q) above which net remobilisation occur. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works) reduced phosphorus retention but not the remobilisation. This may indicate that the presence of impoundments and weirs, or overbank flows may have more control on the phosphorus dynamics under high flow conditions. Further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occurring independently of the unpredictable variability in weather conditions. More research is also needed to quantify the impact of the weir and overbank flows on phosphorus dynamics.

  2. Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution

    Directory of Open Access Journals (Sweden)

    B. O. L. Demars

    2005-01-01

    Full Text Available In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years. In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001, were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The calibrated model explained 79% and 89% of the observed variance before and after phosphorus control, respectively. A split test revealed that predicted TP loads were in good agreement with observed TP loads (r2=0.85, although TP loads were underestimated under high flow conditions. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. This was despite a relatively modest critical discharge (Q above which net remobilisation occur. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works reduced phosphorus retention but not the remobilisation. This may indicate that the presence of impoundments and weirs, or overbank flows may have more control on the phosphorus dynamics under high flow conditions. Further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occurring independently of the unpredictable variability in weather conditions. More research is also needed to quantify the impact of the weir and overbank flows on phosphorus dynamics.

  3. Metagenomic analysis of phosphorus removing sludgecommunities

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Martin, Hector; Ivanova, Natalia; Kunin, Victor; Warnecke,Falk; Barry, Kerrie; McHardy, Alice C.; Yeates, Christine; He, Shaomei; Salamov, Asaf; Szeto, Ernest; Dalin, Eileen; Putnam, Nik; Shapiro, HarrisJ.; Pangilinan, Jasmyn L.; Rigoutsos, Isidore; Kyrpides, Nikos C.; Blackall, Linda Louise; McMahon, Katherine D.; Hugenholtz, Philip

    2006-02-01

    Enhanced Biological Phosphorus Removal (EBPR) is not wellunderstood at the metabolic level despite being one of the best-studiedmicrobially-mediated industrial processes due to its ecological andeconomic relevance. Here we present a metagenomic analysis of twolab-scale EBPR sludges dominated by the uncultured bacterium, "CandidatusAccumulibacter phosphatis." This analysis resolves several controversiesin EBPR metabolic models and provides hypotheses explaining the dominanceof A. phosphatis in this habitat, its lifestyle outside EBPR and probablecultivation requirements. Comparison of the same species from differentEBPR sludges highlights recent evolutionary dynamics in the A. phosphatisgenome that could be linked to mechanisms for environmental adaptation.In spite of an apparent lack of phylogenetic overlap in the flankingcommunities of the two sludges studied, common functional themes werefound, at least one of them complementary to the inferred metabolism ofthe dominant organism. The present study provides a much-needed blueprintfor a systems-level understanding of EBPR and illustrates thatmetagenomics enables detailed, often novel, insights into evenwell-studied biological systems.

  4. Environmental distribution and population biology of Candidatus Accumulibacter, a primary agent of Biological Phosphorus Removal

    OpenAIRE

    Peterson, S. Brook; Warnecke, Falk; Madejska, Julita; McMahon, Katherine D.; Hugenholtz, Philip

    2008-01-01

    Members of the uncultured bacterial genus Candidatus Accumulibacter are capable of intracellular accumulation of inorganic phosphate (Pi) in activated sludge wastewater treatment plants (WWTPs) performing enhanced biological phosphorus removal (EBPR), but were also recently shown to inhabit freshwater and estuarine sediments. Additionally, metagenomic sequencing of two bioreactor cultures enriched in Candidatus Accumulibacter, but housed on separate continents, revealed the potential for glob...

  5. Improved phosphorus use efficiency in agriculture: A key requirement for its sustainable use

    NARCIS (Netherlands)

    Schroder, J.J.; Smit, A.L.; Cordell, D.; Rosemarin, A.

    2011-01-01

    Mineral phosphorus (P) fertilizers processed from fossil reserves have enhanced food production over the past 50 years and, hence, the welfare of billions of people. Fertilizer P has, however, not only been used to lift the fertility level of formerly poor soils, but also allowed people to neglect t

  6. Phosphorus removal from soil using Fe oxide-impregnated paper: Processes and applications

    NARCIS (Netherlands)

    Los, A.M.D.; Temminghoff, E.J.M.; Schenkeveld, W.D.L.; Hiemstra, T.; Riemsdijk, van W.H.

    2009-01-01

    Fe oxide-impregnated paper (Pi-paper) is used as an artificial Phosphorus (P) sink to study P availability in soils and runoff. Pi-papers were introduced as they would mimic P uptake by plant roots by decreasing the P concentration in solution to negligibly low levels and thus enhancing P desorption

  7. IMPROVING PHOSPHORUS NUTRITION OF CORN

    Directory of Open Access Journals (Sweden)

    Walter B. Gordon

    2014-01-01

    Full Text Available Phosphorus (P generally occurs in soils as the anions H2PO4- or HPO4-2 depending on soil pH. These anions readily react with soil cations such as calcium, magnesium, iron and aluminum to produce various phosphate compounds of very limited water solubility. Crop recovery of applied phosphate fertilizer can be quite low during the season of application. In addition, the large amounts of crop residue present in no-tillage production systems can lower soil temperature thus reducing root growth and nutrient uptake of plants even on soils not low in available Phosphorus (P. Specialty Fertilizer Products, Leawood, KS has developed and patented a product registered as AVAIL® that is reported to attract and sequester antagonistic cations out of the soil solution leaving more of the applied P in available form for plant uptake. The objective of this experiment was to evaluate the effectiveness of AVAIL treated P-fertilizer on growth, P-uptake and yield of irrigated corn (Zea mays L. grown in a no-tillage production system. A 3-year experiment was conducted from 2001-2003 at the North Central Kansas Experiment Field, located near Scandia, KS, on a Crete silt loam soil (fine, montmorillonitic, mesic Pachic Arquistoll. Treatments consisted of three rates of P with or without AVAIL. A no P check plot was also included. When averaged over the years and P rates, the use of AVAIL increased yield of corn by 1.1 Mg ha-1. AVAIL also increased corn dry weight at the six-leaf stage, whole plant P uptake at the six-leaf stage and P concentration at mid-silk. The use of AVAIL proved beneficial in overcoming many of the problems associated with P nutrition in corn. AVAIL consistently increased P uptake and yield in this experiment.

  8. Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution

    Directory of Open Access Journals (Sweden)

    B. O. L. Demars

    2005-01-01

    Full Text Available In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years. In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001, were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The effectiveness of phosphorus stripping at two major sewage treatment works was quantified over different hydrological conditions. The model explained 78% and 88% of the observed variance before and after phosphorus control, respectively. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. The critical discharge (Q above which net remobilisation would occur, was only reached during few, high flow events Q25-Q13. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works reduced the phosphorus catchment mass balance variability by 20-24% under the Q99-Q1. range of flow conditions. Although the absorbing capacity of the catchment against human impact was remarkable, further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occuring independently of the unpredictable variability in weather conditions.

  9. Phosphorus-based Flame Retardancy Mechanisms—Old Hat or a Starting Point for Future Development?

    Directory of Open Access Journals (Sweden)

    Bernhard Schartel

    2010-09-01

    Full Text Available Different kinds of additive and reactive flame retardants containing phosphorus are increasingly successful as halogen-free alternatives for various polymeric materials and applications. Phosphorus can act in the condensed phase by enhancing charring, yielding intumescence, or through inorganic glass formation; and in the gas phase through flame inhibition. Occurrence and efficiency depend, not only on the flame retardant itself, but also on its interaction with pyrolysing polymeric material and additives. Flame retardancy is sensitive to modification of the flame retardant, the use of synergists/adjuvants, and changes to the polymeric material. A detailed understanding facilitates the launch of tailored and targeted development.

  10. Phosphorus availability from bottom sediments of lakes using a nuclear technique

    International Nuclear Information System (INIS)

    Availability of phosphorus from the bottom sediments of a lake plays an import role in the development of aquatic biota and in the enhancement of eutrophication process. In this work the 31P↔32P isotopic exchange (E values) technique was applied to assess the potential influence of this phosphorus reservoir on the water quality of Acaray and Yguazu Dams, at the Eastern Region of Paraguay. Samples analyzed were taken from the bottom sediments of the water bodies at different sites as well as from the shores. The method is reliable and yields information of ecological significance

  11. Phosphorus availability from bottom sediments of lakes using a nuclear technique

    International Nuclear Information System (INIS)

    Availability of phosphorus from the bottom sediments of a lake plays an import role in the development of aquatic biota and in the enhancement of the eutrophication process. In this work, the 31P-32P isotopic exchange (E values) technique was applied to assess the potential influence of this phosphorus 'reservoir' on the water quality of the Acaray and Yguazu Dams in the Easter Region of Paraguay. Samples analyzed were taken from the bottom sediments of the water body at different sites as well as from the shores. The method is reliable and yields information of potential ecological significance. (author) 14 refs.; 2 tabs

  12. Epitaxial Growth of Single Layer Blue Phosphorus: A New Phase of Two-Dimensional Phosphorus.

    Science.gov (United States)

    Zhang, Jia Lin; Zhao, Songtao; Han, Cheng; Wang, Zhunzhun; Zhong, Shu; Sun, Shuo; Guo, Rui; Zhou, Xiong; Gu, Cheng Ding; Yuan, Kai Di; Li, Zhenyu; Chen, Wei

    2016-08-10

    Blue phosphorus, a previously unknown phase of phosphorus, has been recently predicted by theoretical calculations and shares its layered structure and high stability with black phosphorus, a rapidly rising two-dimensional material. Here, we report a molecular beam epitaxial growth of single layer blue phosphorus on Au(111) by using black phosphorus as precursor, through the combination of in situ low temperature scanning tunneling microscopy and density functional theory calculation. The structure of the as-grown single layer blue phosphorus on Au(111) is explained with a (4 × 4) blue phosphorus unit cell coinciding with a (5 × 5) Au(111) unit cell, and this is verified by the theoretical calculations. The electronic bandgap of single layer blue phosphorus on Au(111) is determined to be 1.10 eV by scanning tunneling spectroscopy measurement. The realization of epitaxial growth of large-scale and high quality atomic-layered blue phosphorus can enable the rapid development of novel electronic and optoelectronic devices based on this emerging two-dimensional material. PMID:27359041

  13. Total Phosphorus in Surface Water (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALPFuture is reported in kilograms/hectare/year. More information about these resources,...

  14. [Lack of phosphorus intake and nutrition].

    Science.gov (United States)

    Takeda, Eiji; Ikeda, Syoko; Nakahashi, Otoki

    2012-10-01

    Since one gram of protein in food provides approximately 15 mg of phosphorus, phosphorus deficiency frequently observed in patients with protein-energy malnutrition (PEM). Chronic phosphorus deficiency in humans causes proximal myopathy. Acute hypophosphatemia may precipitate rhabdomyolysis. Plasma low phosphorus concentration suppresses erythrocyte synthesis and stores of 2,3-diphosphoglycerate (2,3-DPG) , which plays an important role in the affinity of hemoglobin for oxygen. Symptoms of nervous system dysfunction, such as weakness, apathy, a bedridden state, and intention tremors, are also observed in severe hypophosphatemia. Refeeding syndrome is caused by rapid refeeding in PEM, characterized by hypophosphatemia and has metabolic and clinical complications. This is potentially fatal, yet is preventable. Awareness and identification of at-risk patients is crucial to improving management.

  15. Use of phosphorus release batch tests for modelling an EBPR pilot plant

    DEFF Research Database (Denmark)

    Tykesson, E.; Aspegren, H.; Henze, Mogens;

    2002-01-01

    The aim of this study was to evaluate how routinely performed phosphorus release tests could be used when modelling enhanced biological phosphorus removal (EBPR) using activated sludge models such as ASM2d. A pilot plant with an extensive analysis programme was used as basis for the simulations....... Without any calibration the prediction of phosphorus removal was poor and the initial release rates from the simulations were not similar to those found from the laboratory tests. A period with low organic loading was chosen as a calibration period. In this period averages of daily influent measurements...... a simulated batch test and the PHA uptake rate was increased to fit this release rate with the average initial rates from laboratory batch tests performed during the period. The calibrated model was verified with data from the subsequent period where acetate was dosed....

  16. Possibility in optimization of biological phosphorus removal

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberger, R.

    1989-02-01

    The elimination-efficiency of wastewater treatment plants with biological phosphorus removal is often limited by the following aspects: Low concentrations of organic acids in influent wastewater, hydraulic- and load fluctuations, low anaerobic sludge detention time, transfer of nitrate into the anaerobic zone, phosphorus release in the final clarifier and in sludge treatment units, high effluent suspended solids content. In this context, the following optimization measures seem to be advantageous: 'Activated primary tanks' and 'activated sludge thickeners' are adequate techniques to raise the concentration of organic acids in the wastewater by pre-acidification. Simultaneous acidification takes place in an anaerobic sedimentation basin as realized in the EASC-process (extended anaerobic sludge contact). Below the sludge blanket of an EASC-sedimentation tank, anaerobic conditions can be maintained even in the case of nitrate input. Furthermore, this process is suitable to compensate load- and hydraulic fluctuations of wastewater. To avoid phosphorus release in the final clarifier, it is important to improve sludge settleability. If a low sludge blanket and/or high oxygen concentrations are maintained, phosphorus release in the final clarifier can be limited. Further reduction of total phosphorus is possible with filtration only. Measures against high return flow phosphorus loads are mechanical dewatering of excess sludge and chemical precipitation of digester supernatant.

  17. Recovery of phosphorus from sewerage treatment sludge

    Energy Technology Data Exchange (ETDEWEB)

    Manuilova, Anastasia

    1999-07-01

    This thesis is a review of the current state of technologies for the removal of phosphorus from wastewater and sludge, and the recovery and re-use of phosphorus. It explains the need for phosphorus removal and describes the current removal processes. Focus is given to phosphorus crystallisation processes and to the processes which treat sewage treatment sludges into potential sources of phosphorus. An interesting possibility to recover phosphorus from sewage sludge by use of Psenner fractionation is also discussed. By this method, the following phosphate fractions of technological significance may be distinguished: (1) redox sensitive phosphates, mainly bound to Fe(OH){sub 3}; (2) phosphate adsorbed to surfaces (Al{sub 2}O{sub 3}), exchangeable against OH{sup -}, and alkali-soluble phosphate; (3) phosphate bound to CaCO{sub 3}, MgCO{sub 3} and in apatite; and (4) organically bound phosphate. The basic removal mechanisms, process schemes and treatment results are described. Two experiments with three different types of sludges from Henriksdal wastewater treatment plant in Stockholm were performed in the laboratory. It was shown that the addition of sodium hydroxide or hydrochloric acid cause the significant release of phosphate (about 80%) for all types of sludges. If a whole Psenner fractionation was performed the phosphate release is approximately 100%.

  18. Assessing phosphorus reduction efforts in the Everglades

    Science.gov (United States)

    Tretkoff, Ernie

    2011-05-01

    Years of agricultural and urban runoff have resulted in too much phosphorus in northern regions of the Florida Everglades. To deal with this problem, very large constructed wetlands, known as Stormwater Treatment Areas (STAs), have been built to strip phosphorus from runoff before the water enters protected Everglades areas. The more than $1 billion STA project currently relies on large areas (cells) of submerged aquatic vegetation (SAV) to absorb phosphorus as the final stage of treatment. To evaluate how well the treatment cells are functioning, as well as the potential lower limits of treatment, it is essential to have an accurate picture of the inflows, outflows, and background phosphorus levels. Juston and DeBusk made long-term measurements in one of the SAV cells. They found that after total phosphorous levels in the cells reached about 15 micrograms per liter, no more phosphorus removal occurred. They also analyzed inflow and outflow data from the cell and inferred background phosphorus concentrations for eight additional SAV cells. Background concentrations averaged around 16 micrograms per liter. (Water Resources Research, doi:10.1029/2010WR009294, 2011)

  19. Soil phosphorus constrains biodiversity across European grasslands.

    Science.gov (United States)

    Ceulemans, Tobias; Stevens, Carly J; Duchateau, Luc; Jacquemyn, Hans; Gowing, David J G; Merckx, Roel; Wallace, Hilary; van Rooijen, Nils; Goethem, Thomas; Bobbink, Roland; Dorland, Edu; Gaudnik, Cassandre; Alard, Didier; Corcket, Emmanuel; Muller, Serge; Dise, Nancy B; Dupré, Cecilia; Diekmann, Martin; Honnay, Olivier

    2014-12-01

    Nutrient pollution presents a serious threat to biodiversity conservation. In terrestrial ecosystems, the deleterious effects of nitrogen pollution are increasingly understood and several mitigating environmental policies have been developed. Compared to nitrogen, the effects of increased phosphorus have received far less attention, although some studies have indicated that phosphorus pollution may be detrimental for biodiversity as well. On the basis of a dataset covering 501 grassland plots throughout Europe, we demonstrate that, independent of the level of atmospheric nitrogen deposition and soil acidity, plant species richness was consistently negatively related to soil phosphorus. We also identified thresholds in soil phosphorus above which biodiversity appears to remain at a constant low level. Our results indicate that nutrient management policies biased toward reducing nitrogen pollution will fail to preserve biodiversity. As soil phosphorus is known to be extremely persistent and we found no evidence for a critical threshold below which no environmental harm is expected, we suggest that agro-environmental schemes should include grasslands that are permanently free from phosphorus fertilization.

  20. Phosphorus speciation by coupled HPLC-ICPMS: low level determination of reduced phosphorus in natural materials

    Science.gov (United States)

    Atlas, Zachary; Pasek, Matthew; Sampson, Jacqueline

    2015-04-01

    Phosphorus is a geologically important minor element in the Earth's crust commonly found as relatively insoluble apatite. This constraint causes phosphorus to be a key limiting nutrient in biologic processes. Despite this, phosphorus plays a direct role in the formation of DNA, RNA and other cellular materials. Recent works suggest that since reduced phosphorus is considerably more soluble than oxidized phosphorus that it was integrally involved in the development of life on the early Earth and may continue to play a role in biologic productivity to this day. This work examines a new method for quantification and identification of reduced phosphorus as well as applications to the speciation of organo-phosphates separated by coupled HPLC - ICP-MS. We show that reduced phosphorus species (P1+, P3+ and P5+) are cleanly separated in the HPLC and coupled with the ICPMS reaction cell, using oxygen as a reaction gas to effectively convert elemental P to P-O. Analysis at M/Z= 47 producing lower background and flatter baseline chromatography than analyses performed at M/Z = 31. Results suggest very low detection limits (0.05 μM) for P species analyzed as P-O. Additionally we show that this technique has potential to speciate at least 5 other forms of phosphorus compounds. We verified the efficacy of method on numerous materials including leached Archean rocks, suburban retention pond waters, blood and urine samples and most samples show small but detectible levels of reduced phosphorus and or organo-phaospates. This finding in nearly all substances analyzed supports the assumption that the redox processing of phosphorus has played a significant role throughout the history of the Earth and it's presence in the present environment is nearly ubiquitous with the reduced oxidation state phosphorus compounds, phosphite and hypophosphite, potentially acting as significant constituents in the anaerobic environment.

  1. A nested phosphorus and proton coil array for brain magnetic resonance imaging and spectroscopy.

    Science.gov (United States)

    Brown, Ryan; Lakshmanan, Karthik; Madelin, Guillaume; Parasoglou, Prodromos

    2016-01-01

    A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7T. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4cm nominal isotropic resolution in 15min (2.3cm actual resolution), while additionally enabling 1mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer's and Parkinson's diseases, as well as mental disorders such as schizophrenia.

  2. High performance of nitrogen and phosphorus removal in an electrolysis-integrated biofilter.

    Science.gov (United States)

    Gao, Y; Xie, Y W; Zhang, Q; Yu, Y X; Yang, L Y

    2016-01-01

    A novel electrolysis-integrated biofilter system was developed in this study to evaluate the intensified removal of nitrogen and phosphorus from contaminated water. Two laboratory-scale biofilter systems were established, one with electrolysis (E-BF) and one without electrolysis (BF) as control. The dynamics of intensified nitrogen and phosphorus removal and the changes of inflow and outflow water qualities were also evaluated. The total nitrogen (TN) removal rate was 94.4% in our newly developed E-BF, but only 74.7% in the control BF. Ammonium removal rate was up to 95% in biofilters with or without electrolysis integration with an influent ammonium concentration of 40 mg/L, and the accumulation of nitrate and nitrite was much lower in the effluent of E-BF than that of BF. Thus electrolysis plays an important role in TN removal especially the nitrate and nitrite removal. Phosphorus removal was significantly enhanced, exceeding 90% in E-BF by chemical precipitation, physical adsorption, and flocculation of phosphorus because of the in situ formation of ferric ions by the anodizing of sacrificial iron anodes. Results from this study indicate that the electrolysis integrated biofilter is a promising solution for intensified nitrogen and phosphorus removal. PMID:27508376

  3. A novel control strategy for efficient biological phosphorus removal with carbon-limited wastewaters.

    Science.gov (United States)

    Guerrero, Javier; Guisasola, Albert; Baeza, Juan A

    2014-01-01

    This work shows the development and the in silico evaluation of a novel control strategy aiming at successful biological phosphorus removal in a wastewater treatment plant operating in an A(2)/O configuration with carbon-limited influent. The principle of this novel approach is that the phosphorus in the effluent can be controlled with the nitrate setpoint in the anoxic reactor as manipulated variable. The theoretical background behind this control strategy is that reducing nitrate entrance to the anoxic reactor would result in more organic matter available for biological phosphorus removal. Thus, phosphorus removal would be enhanced at the expense of increasing nitrate in the effluent (but always below legal limits). The work shows the control development, tuning and performance in comparison to open-loop conditions and to two other conventional control strategies for phosphorus removal based on organic matter and metal addition. It is shown that the novel proposed strategy achieves positive nutrient removal results with similar operational costs to the other control strategies and open-loop operation. PMID:25116500

  4. A study on influential factors of high-phosphorus wastewater treated by electrocoagulation-ultrasound.

    Science.gov (United States)

    Li, Jiangping; Song, Chen; Su, Yixin; Long, Hai; Huang, Ta; Yeabah, Trokon Omarley; Wu, Wei

    2013-08-01

    A combined treatment of electrocoagulation and ultrasound was proposed to solve some problems which exist in the phosphorus removal processes in fine chemical industry. The intermittently discharged wastewater has the features of high initial phosphorus concentration and wide initial pH variation. The electrocoagulation-ultrasound effective performance for the removal of phosphorus was investigated. The results obtained from synthetic wastewater showed that the total phosphorus (TP) decreased from 86 to about 0.4 mg/L, and the removal efficiency reached about 99.6 %, when ultrasound was applied to the electrocoagulation cell under the optimum working conditions in 10 min. Comparatively, the TP removal efficiency of electrocoagulation group was 81.3 % and the ultrasound group has almost no change. Therefore, we can conclude that the electrocoagulation and ultrasound synergistic effect can effectively degrade high-phosphorus wastewater. We have discussed the impact of various parameters on the electrocoagulation-ultrasound based on the phosphorus removal efficiency. The results obtained from synthetic wastewater showed that the optimum working pH was found to be 6, allowing the effluent to be met the emission standards without pH adjustment. An increased current enhanced the speed of treatment significance, but higher current (>40 mA/cm(2)) enhanced ultrasonic cavitation effect causing flocculation ineffective. In addition, it was found that the optimum ultrasonic power was 4 W/cm(2) and the frequency was 20 kHz. The best ultrasound intervention and ultrasonic irradiation time were processed with electrocoagulation simultaneously. The results indicated that the electrocoagulation-ultrasound could be utilized as an attractive technique for removal of phosphate in the real wastewater.

  5. The renaissance of black phosphorus

    Science.gov (United States)

    Ling, Xi; Wang, Han; Huang, Shengxi; Xia, Fengnian; Dresselhaus, Mildred S.

    2015-04-01

    One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from condensed matter physicists, chemists, semiconductor device engineers, and material scientists. Similar to graphite and transition metal dichalcogenides (TMDs), black P has a layered structure but with a unique puckered single-layer geometry. Because the direct electronic band gap of thin film black P can be varied from 0.3 eV to around 2 eV, depending on its film thickness, and because of its high carrier mobility and anisotropic in-plane properties, black P is promising for novel applications in nanoelectronics and nanophotonics different from graphene and TMDs. Black P as a nanomaterial has already attracted much attention from researchers within the past year. Here, we offer our opinions on this emerging material with the goal of motivating and inspiring fellow researchers in the 2D materials community and the broad readership of PNAS to discuss and contribute to this exciting new field. We also give our perspectives on future 2D and thin film black P research directions, aiming to assist researchers coming from a variety of disciplines who are desirous of working in this exciting research field.

  6. Soil phosphorus availability and soybean response to phosphorus starter fertilizer

    Directory of Open Access Journals (Sweden)

    Ciro Antonio Rosolem

    2014-10-01

    Full Text Available Phosphorus fixation in tropical soils may decrease under no-till. In this case, P fertilizer could be surface-spread, which would improve farm operations by decreasing the time spend in reloading the planter with fertilizers. In the long term, less soluble P sources could be viable. In this experiment, the effect of surface-broadcast P fertilization with both soluble and reactive phosphates on soil P forms and availability to soybean was studied with or without fertilization with soluble P in the planting furrow in a long-term experiment in which soybean was grown in rotation with Ruzigrass (Brachiaria ruziziensis. No P or 80 kg ha-1 of P2O5 in the form of triple superphosphate or Arad reactive rock phosphate was applied on the surface of a soil with variable P fertilization history. Soil samples were taken to a depth of 60 cm and soil P was fractionated. Soybean was grown with 0, 30, and 60 kg ha-1 of P2O5 in the form of triple phosphate applied in the seed furrow. Both fertilizers applied increased available P in the uppermost soil layers and the moderately labile organic and inorganic forms of P in the soil profile, probably as result of root decay. Soybean responded to phosphates applied on the soil surface or in the seed furrow; however, application of soluble P in the seed furrow should not be discarded. In tropical soils with a history of P fertilization, soluble P sources may be substituted for natural reactive phosphates broadcast on the surface. The planting operation may be facilitated through reduction in the rate of P applied in the planting furrow in relation to the rates currently applied.

  7. Enhanced phosphorus and nitrogen removal from municipal waste water with increased phosphorus release

    Energy Technology Data Exchange (ETDEWEB)

    Rensink, J.H.; Donker, H.J.G.W.; Anink, D.M.

    1989-02-01

    Experiments were carried out in biological P- and N-removal from settled domestic waste water in a pilot activated sludge plant of 1000 l. The pilot plant consisted of 10 interconnected compartments. The compartments 1, 2, 7, 8 and 9 were stirred, while the compartments 3, 4, 5, 6 and 10 were aerated. The waste water was fed into compartment 1 and 7 with a ratio of 3:1. A part of the return sludge was quickly stripped in a tank by dosing 25 mg Na-acetate per g sludge. The stripped sludge was sent back to compartment 3. At dry wheather flow the supernatant of the concentrating phosphate of the stripper tank amounted to 100 mg P/l. The P- and N-content of the settled waste water was respectively reduced to 99,9 and 90%. Further research with this pilot plant is now focussed on the elimination of the phosphate of the supernatant of the strippertank by cristallization of calcium-phosphate in a fluidized bed reactor, developed by DHV Consulting Engineers in the Netherlands. The obtained calcium phosphate pellets can be used in the phosphate industry.

  8. Further developments and field deployment of phosphorus functionalized polymeric scale inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Todd, Malcolm J.; Thornton, Alex R.; Wylde, Jonathan J.; Strachan, Catherine J.; Moir, Gordon [Clariant Oil Services, Muttenz (Switzerland); Goulding, John [John Goulding Consultancy, York (United Kingdom)

    2012-07-01

    As the oil and gas industry strives to replace ageing, environmentally undesirable scale inhibitors there is an ever increasing use of polymeric inhibitors. The incorporation of phosphorous functionality into a polymer backbone has been shown to improve inhibition efficiency, enhance adsorption characteristics and allow the polymer concentration to be analyzed by elemental phosphorus. It is known that some phosphorus tagged polymers can be problematic to analyze in oil field brines as they typically have a low phosphorus content which is difficult to determine from the background. The development of novel phosphorus functionalized polymeric scale inhibitors was previously described (IBP3530-10). This paper follows the development of the inhibitor class. Utilizing extensive laboratory testing the interactive nature of the scale inhibitors and reservoir lithology was studied. These novel phosphorus functionalized inhibitors were compared to a number of other available scale inhibitors. The incorporation of phosphorus functionality into polymeric inhibitors can be expensive utilizing traditional methods as the phosphorus containing monomers are the financially limiting factor. These are typically vinyl phosphonic acid (VPA), or vinyl diphosphonic acid (VDPA). The novel phosphorus functionalized monomers utilized herein are simpler to manufacture allowing higher phosphorus content within the polymer backbone. The addition of phosphorus into a polymer backbone has previously been known to exacerbate analysis issues in some commercially available scale inhibitors. This is due to incomplete polymerization reactions leaving free and/or inorganic phosphorus containing moieties which can interfere with the analysis, or low levels of phosphorus within end-capped polymers can make it difficult to determine the active concentration accurately within field brines which contain many impuritie. Polymeric inhibitors are known to contain a range of molecular weights with varying

  9. Critical phosphorus concentrations in winter wheat genotypes with various phosphorus efficiencies

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Under greenhouse conditions, a pot experiment was conducted to seek critical phosphorus concentrations of wheat genotypes with high and low phosphorus use efficiency. Results indicated that low efficient genotype was much more sensitive to phosphorus deficiency, with low or without phosphorus application, seed yield and dry matter of biomass were much lower. The yield of all the genotypes gradually got higher as application rate increased, but high efficient genotype--Lofflin produced relatively higher yields of seeds and biomass with low or without phosphorus input. Highly tolerate to low availability of soil phosphorus and efficient activation and absorption for soil unavailable phosphorus had been displayed. As application rates increased, yields of both genotypes were increased but high efficient genotype maintained stable while low efficient one showed continuously increase with remuneration decrease progressively. Critical phosphorus concentrations in high efficient genotypes of winter wheat were lower than that in low efficient ones and changed with various development stages, for example, at seedling state, the concentrations of high efficient genotype were 4.50-4.60 g/kg while low efficient one was 5.0 g/kg. They were 2.25-2.30 g/kg and 2.52 g/kg at flower stage, 1.96-2.05 g/kg and 2.15 g/kg at maturity respectively. But the values in seeds were reversal, higher in high efficient genotype(4.05-4.10 g/kg) than that in low efficient(3.90 g/kg). Therefore, phosphorus high efficient genotypes belong to the phosphorus resource saving type.

  10. Supporting phosphorus management in Austria: Potential, priorities and limitations.

    Science.gov (United States)

    Zoboli, Ottavia; Zessner, Matthias; Rechberger, Helmut

    2016-09-15

    Protecting water bodies from eutrophication, ensuring long-term food security and shifting to a circular economy represent compelling objectives to phosphorus management strategies. This study determines how and to which extent the management of phosphorus in Austria can be optimized. A detailed national model, obtained for the year 2013 through Material Flow Analysis, represents the reference situation. Applicability and limitations are discussed for a range of actions aimed at reducing consumption, increasing recycling, and lowering emissions. The potential contribution of each field of action is quantified and compared using three indicators: Import dependency, Consumption of fossil-P fertilizers and Emissions to water bodies. Further, the uncertainty of this assessment is characterized and priorities for the upgrade of data collection are identified. Moreover, all the potential gains discussed in the article are applied to the reference situation to generate an ideal target model. The results show that in Austria a large scope for phosphorus stewardship exists. Strategies based exclusively either on recycling or on the decline of P consumption hold a similar potential to reduce import dependency by 50% each. An enhanced P recycling from meat and bone meal, sewage sludge and compost could replace the current use of fossil-P fertilizers by 70%. The target model, i.e. the maximum that could be achieved taking into account trade-offs between different actions, is characterized by an extremely low import dependency of 0.23kgPcap(-1)y(-1) (2.2kgPcap(-1)y(-1) in 2013), by a 28% decline of emissions to water bodies and by null consumption of fossil-P fertilizers. This case study shows the added value of using Material Flow Analysis as a basis to design sound management strategies. The systemic approach inherent to it allows performing a proper comparative assessment of different actions, identifying priorities, and visualizing a target model. PMID:27177138

  11. Metabolic Adaptations of White Lupin Roots and Shoots under Phosphorus Deficiency

    Science.gov (United States)

    Müller, Julia; Gödde, Victoria; Niehaus, Karsten; Zörb, Christian

    2015-01-01

    White lupin (Lupinus albus L.) is highly adapted to phosphorus-diminished soils. P-deficient white lupin plants modify their root architecture and physiology to acquire sparingly available soil phosphorus. We employed gas chromatography–mass spectrometry (GC-MS) for metabolic profiling of P-deficient white lupins, to investigate biochemical pathways involved in the P-acquiring strategy. After 14 days of P-deficiency, plants showed reduced levels of fructose, glucose, and sucrose in shoots. Phosphorylated metabolites such as glucose-6-phosphate, fructose-6-phosphate, myo-inositol-phosphate and glycerol-3-phosphate were reduced in both shoots and roots. After 22 days of P-deficiency, no effect on shoot or root sugar metabolite levels was found, but the levels of phosphorylated metabolites were further reduced. Organic acids, amino acids and several shikimate pathway products showed enhanced levels in 22-day-old P-deficient roots and shoots. These results indicate that P-deficient white lupins adapt their carbohydrate partitioning between shoot and root in order to supply their growing root system as an early response to P-deficiency. Organic acids are released into the rhizosphere to mobilize phosphorus from soil particles. A longer period of P-deficiency leads to scavenging of Pi from P-containing metabolites and reduced protein anabolism, but enhanced formation of secondary metabolites. The latter can serve as stress protection molecules or actively acquire phosphorus from the soil. PMID:26635840

  12. Secondary poisoning of kestrels by white phosphorus

    Science.gov (United States)

    Sparling, D.W.; Federoff, N.E.

    1997-01-01

    Since 1982, extensive waterfowl mortality due to white phosphorus (P4) has been observed at Eagle River Flats, a tidal marsh near Anchorage, Alaska. Ducks and swans that ingest P4 pellets become lethargic and may display severe convulsions. Intoxicated waterfowl attract raptors and gulls that feed on dead or dying birds. To determine if avian predators can be affected by secondary poisoning, we fed American kestrels (Falco sparverius) 10-day-old domestic chickens that had been dosed with white phosphorus. Eight of 15 kestrels fed intact chicks with a pellet of P4 implanted in their crops died within seven days. Three of 15 kestrels fed chicks that had their upper digestive tracts removed to eliminate any pellets of white phosphorus also died. Hematocrit and hemoglobin in kestrels decreased whereas lactate dehydrogenaseL, glucose, and alanine aminotransferase levels in plasma increased with exposure to contaminated chicks. Histological examination of liver and kidneys showed that the incidence and severity of lesions increased when kestrels were fed contaminated chicks. White phosphorus residues were measurable in 87% of the kestrels dying on study and 20% of the survivors. This study shows that raptors can become intoxicated either by ingesting portions of digestive tracts containing white phosphorus pellets or by consuming tissues of P4 contaminated prey.

  13. Effect of phosphorus-ion implantation on the corrosion resistance and biocompatibility of titanium.

    Science.gov (United States)

    Krupa, D; Baszkiewicz, J; Kozubowski, J A; Barcz, A; Sobczak, J W; Biliński, A; Lewandowska-Szumieł, M; Rajchel, B

    2002-08-01

    This work presents data on the structure and corrosion resistance of titanium after phosphorus-ion implantation with a dose of 10(17)P/cm2. The ion energy was 25keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The corrosion resistance was examined by electrochemical methods in a simulated body fluid at a temperature of 37 C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both phosphorus-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by transmission electron microscope results, the surface layer formed during phosphorus-ion implantation was amorphous. The results of electrochemical examinations indicate that phosphorus-ion implantation increases the corrosion resistance after short-term as well as long-term exposures.

  14. Response of Sugarcane in a Red Ultisol to Phosphorus Rates, Phosphorus Sources, and Filter Cake.

    Science.gov (United States)

    Caione, Gustavo; Prado, Renato de Mello; Campos, Cid Naudi Silva; Rosatto Moda, Leandro; de Lima Vasconcelos, Ricardo; Pizauro Júnior, João Martins

    2015-01-01

    We evaluated the effect of phosphorus application rates from various sources and in the presence or absence of filter cake on soil phosphorus, plant phosphorus, changes in acid phosphatase activity, and sugarcane productivity grown in Eutrophic Red Ultisol. Three P sources were used (triple superphosphate, Araxa rock phosphate, and Bayovar rock phosphate) and four application rates (0, 90, 180, and 360 kg ha(-1) of P2O5) in the presence or absence of filter cake (7.5 t ha(-1), dry basis). The soil P, the accumulated plant P, the leaf acid phosphatase activity and straw, the stalk productivity, the concentration of soluble solids in the juice (Brix), the juice sucrose content (Pol), and the purity were the parameters evaluated. We found that P applications increased levels of soil, leaf, and juice phosphorus and led to higher phosphorus accumulation and greater stalk and straw productivity. These levels were highest in the presence of filter cake. Acid phosphatase activity decreased with increasing plant phosphorus concentration. Phosphate fertilization did not show effect on sugarcane technological quality. We concluded that P application, regardless of source, improved phosphorus nutrition and increased productivity in sugarcane and, when associated with filter cake, reduced the need for mineral fertilizer. PMID:26078993

  15. Response of Sugarcane in a Red Ultisol to Phosphorus Rates, Phosphorus Sources, and Filter Cake

    Science.gov (United States)

    Prado, Renato de Mello; Campos, Cid Naudi Silva; Rosatto Moda, Leandro; de Lima Vasconcelos, Ricardo; Pizauro Júnior, João Martins

    2015-01-01

    We evaluated the effect of phosphorus application rates from various sources and in the presence or absence of filter cake on soil phosphorus, plant phosphorus, changes in acid phosphatase activity, and sugarcane productivity grown in Eutrophic Red Ultisol. Three P sources were used (triple superphosphate, Araxa rock phosphate, and Bayovar rock phosphate) and four application rates (0, 90, 180, and 360 kg ha−1 of P2O5) in the presence or absence of filter cake (7.5 t ha−1, dry basis). The soil P, the accumulated plant P, the leaf acid phosphatase activity and straw, the stalk productivity, the concentration of soluble solids in the juice (Brix), the juice sucrose content (Pol), and the purity were the parameters evaluated. We found that P applications increased levels of soil, leaf, and juice phosphorus and led to higher phosphorus accumulation and greater stalk and straw productivity. These levels were highest in the presence of filter cake. Acid phosphatase activity decreased with increasing plant phosphorus concentration. Phosphate fertilization did not show effect on sugarcane technological quality. We concluded that P application, regardless of source, improved phosphorus nutrition and increased productivity in sugarcane and, when associated with filter cake, reduced the need for mineral fertilizer. PMID:26078993

  16. Response of Sugarcane in a Red Ultisol to Phosphorus Rates, Phosphorus Sources, and Filter Cake

    Directory of Open Access Journals (Sweden)

    Gustavo Caione

    2015-01-01

    Full Text Available We evaluated the effect of phosphorus application rates from various sources and in the presence or absence of filter cake on soil phosphorus, plant phosphorus, changes in acid phosphatase activity, and sugarcane productivity grown in Eutrophic Red Ultisol. Three P sources were used (triple superphosphate, Araxa rock phosphate, and Bayovar rock phosphate and four application rates (0, 90, 180, and 360 kg ha−1 of P2O5 in the presence or absence of filter cake (7.5 t ha−1, dry basis. The soil P, the accumulated plant P, the leaf acid phosphatase activity and straw, the stalk productivity, the concentration of soluble solids in the juice (Brix, the juice sucrose content (Pol, and the purity were the parameters evaluated. We found that P applications increased levels of soil, leaf, and juice phosphorus and led to higher phosphorus accumulation and greater stalk and straw productivity. These levels were highest in the presence of filter cake. Acid phosphatase activity decreased with increasing plant phosphorus concentration. Phosphate fertilization did not show effect on sugarcane technological quality. We concluded that P application, regardless of source, improved phosphorus nutrition and increased productivity in sugarcane and, when associated with filter cake, reduced the need for mineral fertilizer.

  17. Xingfa Group: To Be World-Famous Phosphorus Chemical Enterprise

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ As the biggest fine phosphorus chemical producer in China, Hubei Xingfa Chemicals Co., Ltd. (Xingfa Group, SH: 600141) is mainly engaged in the production and sales of phosphorus chemicals and fine chemicals.

  18. Phosphorus doped TiO{sub 2} as oxygen sensor with low operating temperature and sensing mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Han, Zhizhong; Wang, Jiejie; Liao, Lan [Institute of Research on the Functional Materials, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China); College of Chemistry and Chemical Engineering, Qishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); Pan, Haibo, E-mail: hbpan@fzu.edu.cn [Institute of Research on the Functional Materials, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China); College of Chemistry and Chemical Engineering, Qishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); Shen, Shuifa [Institute of Research on the Functional Materials, Yishan Campus, Fuzhou University, Fuzhou, Fujian 350002 (China); College of Chemistry and Chemical Engineering, Qishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China); Chen, Jianzhong, E-mail: j.z.chen@fzu.edu.cn [College of Chemistry and Chemical Engineering, Qishan Campus, Fuzhou University, Fuzhou, Fujian 350108 (China)

    2013-05-15

    Nano-scale TiO{sub 2} powders doped with phosphorus were prepared by sol–gel method. The characterization of the materials was performed by XRD, BET, FT-IR spectroscopy, Zeta potential measurement and XPS analysis. The results indicate that the phosphorus suppresses the crystal growth and phase transformation and, at the same time, increases the surface area and enhances the sensitivity and selectivity for the P-doped TiO{sub 2} oxygen sensors. In this system, the operating temperature is low, only 116 °C, and the response time is short. The spectra of FT-IR and XPS show that the phosphorus dopant presents as the pentavalent-oxidation state in TiO{sub 2}, further phosphorus can connect with Ti{sup 4+} through the bond of Ti-O-P. The positive shifts of XPS peaks indicate that electron depleted layer of P-doped TiO{sub 2} is narrowed compared with that of pure TiO{sub 2}, and the results of Zeta potential illuminate that the density of surface charge carrier is intensified. The adsorptive active site and Lewis acid characteristics of the surface are reinforced by phosphorus doping, where phosphorus ions act as a new active site. Thus, the sensitivity of P-doped TiO{sub 2} is improved, and the 5 mol% P-doped sample has the optimal oxygen sensing properties.

  19. Environmental Phosphorus Recovery Based on Molecular Bioscavengers

    DEFF Research Database (Denmark)

    Gruber, Mathias Felix

    . Finally, it is shown how computational fluid dynamics can be used to optimize large-scale industrial processes using an open-source model, which we have made freely available online to the membrane community, and the advantages/disadvantages of different potential physical implementations of the proposed......Phosphorus is a ubiquitous element of all known life and as such it is found throughout numerous key molecules related to various cellular functions. The supply of phosphorus is tightly linked to global food security, since phosphorus is used to produce agricultural fertilizers, without which...... characteristic amino acid distributions of the binding sites. Quantum mechanical methods are used to investigate how phosphate moieties are described using electronic structure methods, and molecular dynamics in combination with quantum mechanics are used to show how the dynamical interaction between phosphates...

  20. Identification and Metabolic Mechanism of Non-fermentative Short-cut Denitrifying Phosphorus-removing Bacteria

    Institute of Scientific and Technical Information of China (English)

    LIU Hui; SUN Yanfu; JIA Xiaoshan; LI Jun; ZHOU Kangqun; QU Xiangdong; TAO Xueqin

    2013-01-01

    To investigate the characteristics and metabolic mechanism of short-cut denitrifying phosphorus-removing bacteria (SDPB) that are capable of enhanced biological phosphorus removal (EBPR) using nitrite as an electron acceptor,an aerobic/anoxic sequencing batch reactor was operated under three phases.An SDPB-strain YC was screened after the sludge enrichment and was identified by morphological,physiological,biochemical properties and 16S rDNA gene sequence analysis.Denitrifying phosphorus-removing experiments were conducted to study anaerobic and anoxic metabolic mechanisms by analyzing the changes of chemical oxygen demand (COD),phosphate,nitrite,poly-fβ-hydroxybutyrate (PHB),and glycogen.The results show that strain YC is a non-fermentative SDPB similar to Paracoccus denitrificans.As a kind of non-fermentative bacteria,the energy of strain YC was mainly generated from phosphorus release (96.2%) under anaerobic conditions with 0.32 mg P per mg synthesized PHB.Under anoxic conditions,strain YC accumulated 0.45 mg P per mg degraded PHB,which produced most of energy for phosphate accumulation (91.3%) and a little for glycogen synthesis (8.7%).This metabolic mechanism of strain YC is different from that of traditional phosphorus-accumulating organisms (PAOs).It is also found that PHB,a kind of intracellular polymer,plays a very important role in denitrifying and accumulating phosphorus by supplying sufficient energy for phosphorous accumulation and carbon sources for denitrification.Therefore,monitoring △P/△PHB and △NO2--N/△PHB is more necessary than monitoring △P/△COD,△NO2--N/△COD,or △P/△NO2--N.

  1. Soil Solution Phosphorus Status and Mycorrhizal Dependency in Leucaena leucocephala†

    Science.gov (United States)

    Habte, Mitiku; Manjunath, Aswathanarayan

    1987-01-01

    A phosphorus sorption isotherm was used to establish concentrations of P in a soil solution ranging from 0.002 to 0.807 μg/ml. The influence of P concentration on the symbiotic interaction between the tropical tree legume Leucaena leucocephala and the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum was evaluated in pot experiments. The level of mycorrhizal infection in Leucaena roots increased as the concentration of P was raised from 0.002 to 0.153 μg/ml. Higher levels of P depressed mycorrhizal infection, but the level of infection never declined below 50%. Periodic monitoring of P contents of Leucaena subleaflets indicated that significant mycorrhizal activity was detected as early as 17 days after planting, with the activity peaking 12 to 16 days thereafter. The highest level of mycorrhizal activity was associated with a soil solution P level of 0.021 μg/ml. Even though the mycorrhizal inoculation effect diminished as the concentration of P in the soil solution was increased, mycorrhizal inoculation significantly increased P uptake and dry-matter yield of Leucaena at all levels of soil solution P examined. The concentration of P required by nonmycorrhizal L. leucocephala for maximum yield was 27 to 38 times higher than that required by mycorrhizal L. leucocephala. The results illustrate the very high dependence of L. leucocephala on VAM fungi and the significance of optimizing soil solution phosphorus for enhancing the benefits of the VAM symbiosis. PMID:16347323

  2. Size dependence of phosphorus doping in silicon nanocrystals.

    Science.gov (United States)

    He, Wei; Li, Zhengping; Wen, Chao; Liu, Hong; Shen, Wenzhong

    2016-10-21

    Doping of silicon nanocrystals (Si-NCs) is one of the major challenges for silicon nanoscale devices. In this work, phosphorus (P) doping in Si-NCs which are embedded within an amorphous silicon matrix is realized together with the growth of Si-NCs by plasma-enhanced chemical vapor deposition under a tunable substrate direct current (DC) bias. The variation of phosphorus concentration with substrate bias can be explained by the competition of bonding processes of Si-Si and P-Si bonds. The formation of Si-Si and P-Si bonds is differently influenced by the ion bombardment controlled by the substrate bias, due to their bonding energy difference. We have studied the influences of grain size on P doping in Si-NCs. Free carrier concentration, which is provided by activated P atoms, decreases with decreasing grain size due to increasing formation energy and activation energy of P atoms incorporated in Si-NCs. Furthermore, we have studied the P locations inside Si-NCs and hydrogen passivation of P in the form of P-Si-H complexes using the first-principles method. Hydrogen passivation of P can also contribute to the reduced free carrier concentration in smaller Si-NCs. These results provide valuable understanding of P doping in Si-NCs. PMID:27632417

  3. Aluminum-Based Water Treatment Residue Reuse for Phosphorus Removal

    Directory of Open Access Journals (Sweden)

    Lai Yoke Lee

    2015-04-01

    Full Text Available Aluminum-based water treatment residue (Al-WTR generated during the drinking water treatment process is a readily available recycled material with high phosphorus (P adsorption capacity. The P adsorption capacity of Al-WTR generated from Singapore’s water treatment plant was evaluated with reference to particle size range, adsorption pH and temperature. Column tests, with WTR amendments in sand with and without compost, were used to simulate the bioretention systems. The adsorption rate decreased with increasing WTR sizes. Highest P adsorption capacity, 15.57 mg PO43−-P/g WTR, was achieved using fine WTR particles (>50% particles at less than 0.30 mm. At pH 4, the contact time required to reduce effluent P concentration to below the detectable range was half compared with pH 7 and 9. The adsorption rate observed at 40 ± 2 °C was 21% higher compared with that at 30 ± 2 °C. Soil mixes amended with 10% WTR and compost were able to maintain consistently high (90% total phosphorus (TP removal efficiency at a TP load up to 6.45 g/m3. In contrast, TP removal efficiencies associated with columns without WTR amendment decreased to less than 45% as the TP load increased beyond 4.5 g/m3. The results showed that WTR application is beneficial for enhanced TP removal in bioretention systems.

  4. Effect of humic substances on phosphorus removal by struvite precipitation.

    Science.gov (United States)

    Zhou, Zhen; Hu, Dalong; Ren, Weichao; Zhao, Yuzeng; Jiang, Lu-Man; Wang, Luochun

    2015-12-01

    Humic substances (HS) are a major fraction of dissolved organic matters in wastewater. The effect of HS on phosphorus removal by struvite precipitation was investigated using synthetic wastewater under different initial pH values, Mg/P molar ratios and HS concentrations. The composition, morphology and thermal properties of harvested precipitates were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and thermo-gravimetric analysis (TGA), respectively. It showed that inhibition effect of HS reached its maximum value of 48.9% at pH 8.0, and decreased to below 10% at pH>9.0. The increase of Mg/P ratio enhanced phosphorus removal efficiency, and thus reduced the influence of HS on struvite precipitation. At pH 9.0, the inhibitory effect of initial HS concentration matched the modified Monod model with half maximum inhibition concentration of 356mgL(-1), and 29% HS was removed in conjunction with struvite crystallisation. XRD analysis revealed that the crystal form of struvite precipitates was changed in the presence of HS. The morphology of harvested struvite was transformed from prismatic to pyramid owing to the coprecipitation of HS on crystal surface. TGA results revealed that the presence of HS could compromise struvite purity. PMID:26151483

  5. Transcriptional responses of maize seedling root to phosphorus starvation.

    Science.gov (United States)

    Lin, Hai-Jian; Gao, Jian; Zhang, Zhi-Ming; Shen, Ya-Ou; Lan, Hai; Liu, Li; Xiang, Kui; Zhao, Maojun; Zhou, Shufeng; Zhang, Yong-Zhong; Gao, Shi-Bin; Pan, Guang-Tang

    2013-09-01

    Maize (Zea mays) is the most widely cultivated crop around the world, however, it is commonly affected by phosphate (Pi) deficiency and the underlying molecular basis of responses mechanism is still unknown. In this study, the transcriptional response of maize roots to Pi starvation at 3 days after the onset of Pi deprivation was assessed. The investigation revealed a total of 283 Pi-responsive genes, of which 199 and 84 genes were found to be either up- or down-regulated respectively, by 2-fold or more. Pi-responsive genes were found to be involved in sugar and nitrogen metabolic pathways, ion transport, signal transduction, transcriptional regulation, and other processes related to growth and development. In addition, the expression patterns of maize inorganic phosphorus transporters, acid phosphatase, phytase, 2-deoxymugineic acid synthase1, POD and MYB transcription factor were validated in 178 roots response to low phosphorus stress. of which, two genes encoding phytase and acid phosphatase were significantly induced by Pi deficiency and may play a pivotal role in the process of absorption and re-utilization of Pi in Maize. These results not only enhance our knowledge about molecular processes associated with Pi deficiency, but also facilitate the identification of key molecular determinants for improving Pi use in maize. Moreover, this work sets a framework to produce Pi-specific maize microarrays to study the changes in global gene expression between Pi-efficient and Pi-inefficient maize genotypes. PMID:23670044

  6. The release of dissolved phosphorus from lake sediments.

    OpenAIRE

    Boers, P.C.M.

    1991-01-01

    Chapter 1. Introduction: Eutrophication is one of the world's major water quality problems. Attempts to alleviate eutrophication of lakes have involved the control of phosphorus loadings. In such cases, an internal loading of phosphorus from the sediments may retard an improvement of the water quality. Chapters 2 - 5 deal specifically with the sediments of Lake Loosdrecht.Chapter 2. Distribution and forms of phosphorus in the sediments of the Loosdrecht Lakes (the Netherlands): The phosphorus...

  7. Mechanical properties of low alloy high phosphorus weathering steel

    OpenAIRE

    Jena B.K.; Gupta N; Singh B; Ahoo G.S.

    2015-01-01

    Mechanical behaviour of two low alloy steels (G11 and G12) was studied with respect to different phosphorus contents. Tensile strength and yield strength increased while percentage elongation at fracture decreased on increasing phosphorus content. The SEM and light optical photomicrograph of low phosphorus steel (G11) revealed ferrite and pearlite microstructure. On increasing phosphorus content from 0.25 wt.% to 0.42 wt.%, the morphology of grain changed f...

  8. Response of Sugarcane in a Red Ultisol to Phosphorus Rates, Phosphorus Sources, and Filter Cake

    OpenAIRE

    Gustavo Caione; Renato de Mello Prado; Cid Naudi Silva Campos; Leandro Rosatto Moda; Ricardo de Lima Vasconcelos; João Martins Pizauro Júnior

    2015-01-01

    We evaluated the effect of phosphorus application rates from various sources and in the presence or absence of filter cake on soil phosphorus, plant phosphorus, changes in acid phosphatase activity, and sugarcane productivity grown in Eutrophic Red Ultisol. Three P sources were used (triple superphosphate, Araxa rock phosphate, and Bayovar rock phosphate) and four application rates (0, 90, 180, and 360 kg ha−1 of P2O5) in the presence or absence of filter cake (7.5 t ha−1, dry basis). The soi...

  9. Improving methane production and phosphorus release in anaerobic digestion of particulate saline sludge from a brackish aquaculture recirculation system.

    Science.gov (United States)

    Zhang, Xuedong; Ferreira, Rui B; Hu, Jianmei; Spanjers, Henri; van Lier, Jules B

    2014-06-01

    In this study, batch tests were conducted to examine the effects of trehalose and glycine betaine as well as potassium on the specific methanogenic activity (SMA), acid and alkaline phosphatase activity of anaerobic biomass and phosphorus release in anaerobic digestion of saline sludge from a brackish recirculation aquaculture system. The results of ANOVA and Tukey's HSD (honestly significant difference) tests showed that glycine betaine and trehalose enhanced SMA of anaerobic biomass and reactive phosphorus release from the particulate waste. Moreover, SMA tests revealed that methanogenic sludge, which was long-term acclimatized to a salinity level of 17 g/L was severely affected by the increase in salinity to values exceeding 35 g/L. Addition of compatible solutes, such as glycine betaine and trehalose, could be used to enhance the specific methane production rate and phosphorus release in anaerobic digestion from particulate organic waste produced in marine or brackish aquaculture recirculation systems.

  10. Phosphorus, beverages, and chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Di Irorio B

    2012-10-01

    Full Text Available Biagio Di Iorio, Lucia Di Micco, Serena Torraca, Maria Luisa SiricoNephrology-Medicine Department, "A Landolfi" Hospital, Solofra, ItalyAbstract: Phosphate is present in food in two forms, ie, organic and inorganic phosphate salts, which are naturally present in food and as phosphates added for industrial and commercial reasons. There is also a high content of added phosphate in beverages, and phosphates in this form are highly absorbable. The real content of phosphate contained in beverages is often unrecognized, and nephrologists do not always take into account the amount of phosphorus that patients ingest in this form.Keywords: phosphorus, beverages, additive, diet

  11. Homogeneous phosphorus of silicon by neutron transmutation

    International Nuclear Information System (INIS)

    The manufacture of high-voltage power semiconductors requires a homogeneous phosphorus doping of silicon within extremely narrow limits. It was the aim of the investigations to develop neutron irradiation as a means to homogeneously dope silicon with phosphorus on an industrial scale. Special attention was given to the selection of suitable reactor positions, the annealing of the irradiation damage, and the electrical properties of the devices. The experience with the application of neutron irradiated silicon for a wide spectrum of devices shows that expected homogeneity and aiming accuracy with respect to the doping can be reached with high reliability. (orig.) 891 ORU/orig. 892 MB

  12. IMPROVING PHOSPHORUS NUTRITION OF COTTON

    Directory of Open Access Journals (Sweden)

    Walter B. Gordon

    2014-01-01

    Full Text Available Crop recovery of applied Phosphorus (P fertilizer can be low, especially during season of low soil temperature, which decreases plant root growth and nutrient uptake. The H2PO4- or HPO4-2 anions readily react with soil cations such as Calcium (Ca, Magnesium (Mg, iron (Fe and Aluminum (Al to produce various phosphate compounds of very limited water solubility. Specialty Fertilizer Products (SFP, Leawood, KS, USA has developed and patented a product registered as AVAIL® that is reported to attract and sequester antagonistic cations out of the soil solution leaving more of applied P in available form for plant uptake. To evaluate effectiveness of AVAIL product for cotton production, experiments were conducted in two locations in West Tennessee, Grand Junction (GJ in Hardeman County and Ames Plantation (AP located in Fayette County. Treatments consisted of applying Mono-Ammonium Phosphate (MAP, 11-52-0 alone or coated with AVAIL at rates of 34 or 68 kg ha-1 P2O5. A no P check was also included. An additional treatment consisting of AVAIL treated P in combination with Nutrisphere-N®, a Nitrogen (N stabilizer product offered by SFP, was also included. At GJ site, when averaged over P rates and years, AVAIL treated MAP improved tissue P concentration and increased cotton lint yield by 157 kg ha-1 over untreated MAP. At AP site, when averaged over years and P rates, application of AVAIL treated MAP increased cotton lint yield by 85 kg ha-1 over untreated MAP. In both experiments, 34 kg ha-1 AVAIL treated MAP produced higher tissue P concentrations and greater yields than 68 kg ha-1 without AVAIL. Influencing reactions in the micro-environment around the fertilizer granule has proven to have a significant benefit on the yield and P uptake of cotton. More research is needed to determine P content in the soil and further

  13. Effect of Phosphorus and Irrigation Levels on Yield, Water Productivity, Phosphorus Use Efficiency and Income of Lowland Rice in Northwest Pakistan

    Institute of Scientific and Technical Information of China (English)

    Khalid USMAN

    2013-01-01

    With decreasing availability of water for agriculture and increasing demand for rice production,an optimum use of irrigation water and phosphorus may guarantee sustainable rice production.Field experiments were conducted in 2003 and 2004 to investigate the effect of phosphorus and irrigation levels on yield,water productivity (WP),phosphorus use efficiency (PUE) and income of low land rice.The experiment was laid out in randomized complete block design with split plot arrangements replicated four times.Main plot consisted of five phosphorus levels,viz.0 (P0),50 (P50),100 (P100),150(P150),and 200 (P200) kg/hm2,while subplots contained of irrigation times,i.e.8 (I8),10 (I10),12 (I12),and 14 (I14) irrigation levels,each with a water depth of 7.5 cm.Mean values revealed that P150 in combination with I10 produced the highest paddy yield (9.8 t/hm2) and net benefit (1231.8 US$/hm2)among all the treatments.Phosphorus enhanced WP when applied in appropriate combination with irrigation level.The highest mean WP [13.3 kg/(hm2·mm)] could be achieved at P150 with I8 and decreased with increase in irrigation level,while the highest mean PUE (20.1 kg/kg) could be achieved at P100 with I10 and diminished with higher P levels.The overall results indicate that P150 along with I10 was the best combination for sustainable rice cultivation in silty clay soil.

  14. Phosphorus flows and balances of the European Union Member States

    NARCIS (Netherlands)

    Dijk, van K.C.; Lesschen, J.P.; Oenema, O.

    2015-01-01

    Global society faces serious “phosphorus challenges” given the scarcity, essentiality, unequal global distribution and, at the same time, regional excess of phosphorus (P). Phosphorus flow studies can be used to analyze these challenges, providing insight into how society (re)uses and loses phosphor

  15. 77 FR 46298 - Phosphorus Water Quality Standards for Florida Everglades

    Science.gov (United States)

    2012-08-03

    ... AGENCY 40 CFR Part 131 RIN 2040-AF38 Phosphorus Water Quality Standards for Florida Everglades AGENCY... provisions of Florida's Water Quality Standards for Phosphorus in the Everglades Protection Area (Phosphorus... are not applicable water quality standards for purposes of the Clean Water Act. EPA is...

  16. Reaching ultra low phosphorus concentrations by filtration techniques

    NARCIS (Netherlands)

    Scherrenberg, S.M.

    2011-01-01

    This research deals with tertiary treatment techniques used for the removal of phosphorus from wastewater treatment plant (WWTP) effluent. The main objective of this research is to obtain ultra low total phosphorus (<0.15 mg total phosphorus/L) concentrations by coagulation, flocculation and filtrat

  17. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Epoxy resin containing phosphorus... Specific Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance... epoxy resin containing phosphorus (PMN P-00-912) is subject to reporting under this section for...

  18. Availability of phosphorus contained in poultry litter for lambs.

    Science.gov (United States)

    Tagari, H; Silanikove, N; Hurwitz, S

    1981-03-01

    Percentage net phosphorus availability (NPHA) and set phosphorus utilization (NPHU) of the phosphorus contained in a heat-sterilized poultry litter (PL) as compared to feed grade dicalcium phosphate (DCP) for lambs was assessed by the "slope" method. The method was based on the evaluation of the function of apparent phosphorus absorption (NPHA), or retention (NPHU), on phosphorus intake. Nitrogen retention was also evaluated. Plasma inorganic phosphorus concentration as a function of phosphorus intake was evaluated and compared to NPHA and NPHU. The percentage of NPHA was found to be 63.7 and 39, and that of NPHU was 63 and 38 for the phosphorus supplied by DCP and PL, respectively. Thus, the NPHA or NPHU for the phosphorus contained in PL is 60.9 and 60.3% of that of DCP, respectively. The slope ratio between the two phosphate supplements as observed for plasma inorganic phosphorus concentrations was similar to those found for NPHA and NPHU but the coefficient of variation was 5 times higher. Nitrogen digestibility was not affected by the level of phosphorus in the diets. Correlation between nitrogen retention and NPHA or NPHU was, however, significant (P less than 0.05). The slopes of dependence of N retention upon phosphorus intake were 2.81 and 1.6 (P less than 0.05) for DCP and PL treatments, respectively, and the ratio between the slopes was 0.57, close to the ratio of NPHU in PL to DCP-supplemented diets.

  19. Synchronous Upgrading Iron and Phosphorus Removal from High Phosphorus Oolitic Hematite Ore by High Temperature Flash Reduction

    OpenAIRE

    Deqing Zhu; Zhengqi Guo; Jian Pan; Feng Zhang

    2016-01-01

    In this paper, an effective method was developed to remove phosphorus and upgrade iron from high phosphorus oolitic hematite ore by high temperature flash reduction—a wet magnetic separation process. A thermodynamic analysis of iron and phosphorus mineral reactions and experiments with Fe-P separation process were performed, and the mechanism of phosphorus removal and beneficiation of iron is discussed as well. The results show that under the proper conditions, a final metallic iron powder as...

  20. Solutions Network Formulation Report. The Potential Contributions of the Global Precipitation Measurement Mission to Phosphorus Reduction Efforts in the Florida Everglades

    Science.gov (United States)

    Anderson, Daniel; Hilbert, Kent; Lewis, David

    2009-01-01

    This candidate solution suggests the use of GPM precipitation observations to enhance the CERP. Specifically, GPM measurements could augment in situ precipitation data that are used to model agricultural phosphorus discharged into the Everglades. This solution benefits society by aiding water resource managers in identifying effective phosphorus reduction scenarios and thereby returning the Everglades to a more natural state. This solution supports the Water Management, Coastal Management, and Ecological Forecasting National Applications.

  1. Changes of water quality and sediment phosphorus of a small productive lake following decreased phosphorus loading

    OpenAIRE

    Heaney, S. I.; Corry, J.E.; Lishman, J.P.

    1992-01-01

    Esthwaite Water is the most productive or eutrophic lake in the English Lake District. Since 1945 its water quality has been determined from weekly or biweekly measurements of temperature, oxygen, plant nutrients and phytoplankton abundance. The lake receives phosphorus from its largely lowland-pasture catchment, sewage effluent from the villages of Hawkshead and Near Sawrey, and from a cage-culture fish farm. From 1986 phosphorus has been removed from the sewage effluent of Hawkshead which w...

  2. Effect of Form and Amount of Phosphorus and Phytase Supplementation on Phosphorus Utilization by Ruminants

    OpenAIRE

    Shanklin, Rachel Kristina

    2001-01-01

    EFFECT OF AMOUNT AND FORM OF PHOSPHORUS AND PHYTASE SUPPLEMENTATION ON PHOSPHORUS UTILIZATION BY RUMINANTS by Rachel Kristina Shanklin Committee Chair, Joseph P. Fontenot Animal and Poultry Sciences (ABSTRACT) The use of animal manures to replace commercial fertilizer has increased the economic and environmental sustainability of agriculture. However, this practice has resulted in excess P being applied to the soil in some areas. Excess P may run-off into surface wa...

  3. Lake Erie phosphorus loading and Cladophora updates

    Science.gov (United States)

    The presentation will focus on updates or progress being made on each Phosphorus Loadings and Cladophora for Lake Erie. The format will give a brief summary of data, findings, and results that were used by the Great Lakes Water Quality Agreement (GLWQA) Annex 4 Nutrients Modeli...

  4. Phosphorus recycling from the waste sector

    NARCIS (Netherlands)

    Ruijter, de F.J.; Dijk, Van W.; Curth-van Middelkoop, J.C.; Reuler, van H.

    2015-01-01

    An efficient use of phosphorus (P) is necessary as phosphate rock is a finite resource and P is essential for crop production. From the waste sector in the Netherlands, 23 Mkg P is sequestered in landfill, incineration ashes and cement. Flows containing P are discussed, together with options to reco

  5. Use of reactive materials to bind phosphorus

    NARCIS (Netherlands)

    Chardon, W.J.; Groenenberg, J.E.; Temminghoff, E.J.M.; Koopmans, G.F.

    2012-01-01

    Phosphorus (P) losses from agricultural soils have caused surface water quality impairment in many regions of the world, including The Netherlands. Due to the large amounts of P accumulated in Dutch soils, the generic fertilizer and manure policy will not be sufficient to reach in time the surface w

  6. Stewardship to tackle global phosphorus inefficiency

    NARCIS (Netherlands)

    Withers, P.J.A.; Dijk, van K.C.; Neset, T.S.S.; Nesme, Thomas; Oenema, Oene; Rubæk, G.H.; Schoumans, O.F.; Smit, Bert; Pellerin, Sylvain

    2015-01-01

    The inefficient use of phosphorus (P) in the food chain is a threat to the global aquatic environment and the health and well-being of citizens, and it is depleting an essential finite natural resource critical for future food security and ecosystem function. We outline a strategic framework of 5

  7. Nanotubes based on monolayer blue phosphorus

    KAUST Repository

    Montes, E.

    2016-07-08

    We demonstrate structural stability of monolayer zigzag and armchair blue phosphorus nanotubes by means of molecular dynamics simulations. The vibrational spectrum and electronic band structure are determined and analyzed as functions of the tube diameter and axial strain. The nanotubes are found to be semiconductors with a sensitive indirect band gap that allows flexible tuning.

  8. Phosphate recycling in the phosphorus industry

    NARCIS (Netherlands)

    Schipper, W.J.; Klapwijk, A.; Potjer, A.; Rulkens, W.H.; Temmink, B.G.; Kiestra, F.D.G.; Lijmbach, A.C.M.

    2001-01-01

    The feasibility of phosphate recycling in the white phosphorus production process is discussed. Several types of materials may be recycled, provided they are dry inorganic materials, low in iron, copper and zinc. Sewage sludge ash may be used if no iron is used for phosphate precipitation in the tre

  9. Phosphorus recovery from sewage sludge char ash

    NARCIS (Netherlands)

    Atienza-Martinez, M.; Gea, G.; Arauzo, J.; Kersten, S.R.A.; Kootstra, A.M.J.

    2014-01-01

    Phosphorus was recovered from the ash obtained after combustion at different temperatures (600 °C, 750 °C and 900 °C) and after gasification (at 820 °C using a mixture of air and steam as fluidising agent) of char from sewage sludge fast pyrolysis carried out at 530 °C. Depending on the leaching con

  10. Temperature-dependant study of phosphorus ion implantation in germanium

    Science.gov (United States)

    Razali, M. A.; Smith, A. J.; Jeynes, C.; Gwilliam, R. M.

    2012-11-01

    We present experimental results on shallow junction formation in germanium by phosphorus ion implantation and standard rapid thermal processing. An attempt is made to improve phosphorus activation by implanting phosphorus at high and low temperature. The focus is on studying the germanium damage and phosphorus activation as a function of implant temperature. Rutherford backscattering spectrometry with channelling and Hall Effect measurements are employed for characterisation of germanium damage and phosphorus activation, respectively. High and low temperature implants were found to be better compared to room temperature implant.

  11. Improving settleability and achieving biological phosphorus removal through the application of sidestream gravimetric selectors

    OpenAIRE

    Welling, Claire Marie

    2015-01-01

    This project utilizes hydrocyclones in wastewater treatment to select for heavier solids, and has been used before in multiple small-scale systems. This is the first implementation of hydrocyclones in a full-scale plant for the purpose of increased settleability, while also achieving enhanced biological phosphorus removal without the use of an anaerobic selector. Hydrocyclones receive mixed liquor tangentially and separate light solids from more dense solids through their tapered shape, in...

  12. Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress

    OpenAIRE

    Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

    2015-01-01

    Abstract: Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake...

  13. Phosphorus reduction by sifting fish waste meal

    Directory of Open Access Journals (Sweden)

    Ronaldo Lima de Lima

    2014-10-01

    Full Text Available Fish meal is widely included in animal feed because it contains ideal essential amino acids profile, it is rich in energy, essential fatty acids, vitamins and minerals and with >80% apparent protein digestibility in peneid shrimp. In human nutrition, studies are investigating the inclusion of fish meal in snacks, cakes, breads and cookies, as an enrichment in calcium, phosphorus, iron, protein and, especially, omega-3 fatty acids. Omega-3 fatty acids reduces heart diseases and have antithrombotic and anti-inflammatory properties (eicosapentaenoic acid, and are essential to the formation of brain tissue and retina in infants and are important during pregnancy and lactation (docosahexaenoic acid. Fish meal produced from fish waste is rich in minerals (phosphorus, which may cause eutrophication and impair water quality in aquaculture. The aim of this study was to reduce phosphorus content from commercial fish meal produced from waste by sifting (0.60 - 1.00 - 1.18 - 1.40 - 2.36 and 3.35mm mesh sizes. Fish meal samples were collected monthly for 24 months. Proximate composition of subsamples per mesh size was compared to the unsieved sample. Results indicate that sifting through a 0.60mm sieve total phosphorus and ash contents were reduced up to 32% and 36%, respectively, further to increase protein content up to 20%. Average composition of the subsamples was 47.04% ash, 5.56% of total phosphorus and 39.45% protein, suggesting that the residue of the fractionation may be marketed as a mineral and protein supplement.

  14. Stabilization of the coupled oxygen and phosphorus cycles by the evolution of bioturbation

    Science.gov (United States)

    Boyle, R. A.; Dahl, T. W.; Dale, A. W.; Shields-Zhou, G. A.; Zhu, M.; Brasier, M. D.; Canfield, D. E.; Lenton, T. M.

    2014-09-01

    Animal burrowing and sediment-mixing (bioturbation) began during the run up to the Ediacaran/Cambrian boundary, initiating a transition between the stratified Precambrian and more well-mixed Phanerozoic sedimentary records, against the backdrop of a variable global oxygen reservoir probably smaller in size than present. Phosphorus is the long-term limiting nutrient for oxygen production via burial of organic carbon, and its retention (relative to carbon) within organic matter in marine sediments is enhanced by bioturbation. Here we explore the biogeochemical implications of a bioturbation-induced organic phosphorus sink in a simple model. We show that increased bioturbation robustly triggers a net decrease in the size of the global oxygen reservoir--the magnitude of which is contingent upon the prescribed difference in carbon to phosphorus ratios between bioturbated and laminated sediments. Bioturbation also reduces steady-state marine phosphate levels, but this effect is offset by the decline in iron-adsorbed phosphate burial that results from a decrease in oxygen concentrations. The introduction of oxygen-sensitive bioturbation to dynamical model runs is sufficient to trigger a negative feedback loop: the intensity of bioturbation is limited by the oxygen decrease it initially causes. The onset of this feedback is consistent with redox variations observed during the early Cambrian rise of bioturbation, leading us to suggest that bioturbation helped to regulate early oxygen and phosphorus cycles.

  15. Phosphorus removal coupled to bioenergy production by three cyanobacterial isolates in a biofilm dynamic growth system.

    Science.gov (United States)

    Gismondi, Alessandra; Pippo, Francesca Di; Bruno, Laura; Antonaroli, Simonetta; Congestri, Roberta

    2016-09-01

    In the present study a closed incubator, designed for biofilm growth on artificial substrata, was used to grow three isolates of biofilm-forming heterocytous cyanobacteria using an artificial wastewater secondary effluent as the culture medium. We evaluated biofilm efficiency in removing phosphorus, by simulating biofilm-based tertiary wastewater treatment and coupled this process with biodiesel production from the developed biomass. The three strains were able to grow in the synthetic medium and remove phosphorus in percentages, between 6 and 43%, which varied between strains and also among each strain according to the biofilm growth phase. Calothrix sp. biofilm turned out to be a good candidate for tertiary treatment, showing phosphorus reducing capacity (during the exponential biofilm growth) at the regulatory level for the treated effluent water being discharged into natural water systems. Besides phosphorus removal, the three cyanobacterial biofilms produced high quality lipids, whose profile showed promising chemical stability and combustion behavior. Further integration of the proposed processes could include the integration of oil extracted from these cyanobacterial biofilms with microalgal oil known for high monounsaturated fatty acids content, in order to enhance biodiesel cold flow characteristics.

  16. Model of phosphorus precipitation and crystal formation in electric arc furnace steel slag filters.

    Science.gov (United States)

    Claveau-Mallet, Dominique; Wallace, Scott; Comeau, Yves

    2012-02-01

    The objective of this study was to develop a phosphorus retention mechanisms model based on precipitation and crystallization in electric arc furnace slag filters. Three slag columns were fed during 30 to 630 days with a reconstituted mining effluent at different void hydraulic retention times. Precipitates formed in columns were characterized by X-ray diffraction and transmission electronic microscopy. The proposed model is expressed in the following steps: (1) the rate limiting dissolution of slag is represented by the dissolution of CaO, (2) a high pH in the slag filter results in phosphorus precipitation and crystal growth, (3) crystal retention takes place by filtration, settling and growth densification, (4) the decrease in available reaction volume is caused by crystal and other particulate matter accumulation (and decrease in available reaction time), and (5) the pH decreases in the filter over time if the reaction time is too low (which results in a reduced removal efficiency). Crystal organization in a slag filter determines its phosphorus retention capacity. Supersaturation and water velocity affect crystal organization. A compact crystal organization enhances the phosphorus retention capacity of the filter. A new approach to define filter performance is proposed: saturation retention capacity is expressed in units of mg P/mL voids.

  17. Phosphorus removal coupled to bioenergy production by three cyanobacterial isolates in a biofilm dynamic growth system.

    Science.gov (United States)

    Gismondi, Alessandra; Pippo, Francesca Di; Bruno, Laura; Antonaroli, Simonetta; Congestri, Roberta

    2016-09-01

    In the present study a closed incubator, designed for biofilm growth on artificial substrata, was used to grow three isolates of biofilm-forming heterocytous cyanobacteria using an artificial wastewater secondary effluent as the culture medium. We evaluated biofilm efficiency in removing phosphorus, by simulating biofilm-based tertiary wastewater treatment and coupled this process with biodiesel production from the developed biomass. The three strains were able to grow in the synthetic medium and remove phosphorus in percentages, between 6 and 43%, which varied between strains and also among each strain according to the biofilm growth phase. Calothrix sp. biofilm turned out to be a good candidate for tertiary treatment, showing phosphorus reducing capacity (during the exponential biofilm growth) at the regulatory level for the treated effluent water being discharged into natural water systems. Besides phosphorus removal, the three cyanobacterial biofilms produced high quality lipids, whose profile showed promising chemical stability and combustion behavior. Further integration of the proposed processes could include the integration of oil extracted from these cyanobacterial biofilms with microalgal oil known for high monounsaturated fatty acids content, in order to enhance biodiesel cold flow characteristics. PMID:26939844

  18. Integrated physicochemical and biological treatment process for fluoride and phosphorus removal from fertilizer plant wastewater.

    Science.gov (United States)

    Gouider, Mbarka; Mlaik, Najwa; Feki, Mongi; Sayadi, Sami

    2011-08-01

    The phosphate fertilizer industry produces highly hazardous and acidic wastewaters. This study was undertaken to develop an integrated approach for the treatment of wastewaters from the phosphate industry. Effluent samples were collected from a local phosphate fertilizer producer and were characterized by their high fluoride and phosphate content. First, the samples were pretreated by precipitation of phosphate and fluoride ions using hydrated lime. The resulting low- fluoride and phosphorus effluent was then treated with the enhanced biological phosphorus removal (EBPR) process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two-stage anaerobic/aerobic system operating under continuous flow. Pretreated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate (OLR) from 0.3 to 1.2 g chemical oxygen demand (COD)/L.d. The stable and high removal rates of COD, NH4(+)-N, and PO4(3-)-P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L, and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively. PMID:21905410

  19. Impact of Fish Farming on Phosphorus in Reservoir Sediments

    Science.gov (United States)

    Jia, Binyang; Tang, Ya; Tian, Liyan; Franz, Leander; Alewell, Christine; Huang, Jen-How

    2015-11-01

    Fish farming has seriously influenced the aquatic environment in Sancha reservoir in SW China since 1985 and has been strongly restricted since 2005. Thus, phosphorus speciation in a sediment core dated between 1945 and 2010 at cm-resolution and in surface sediments from Sancha reservoir may allow us track how fish farming impacts phosphorus dynamics in lake sediments. Fish farming shifts the major binding forms of phosphorus in sediments from organic to residual phosphorus, which mostly originated from fish feed. Sorption to metal oxides and association with organic matters are important mechanisms for phosphorus immobilisation with low fish farming activities, whereas calcium-bound phosphorous had an essential contribution to sediment phosphorus increases under intensive fish framing. Notwithstanding the shifting, the aforementioned phosphorus fractions are usually inert in the lake environment, therefore changing phosphorus mobility little. The use of fish feed and water-purification reagents, the most important additives for fish farming, introduce not only phosphorus but also large amounts of sand-sized minerals such as quartz into the lake, to which phosphorus weakly sorbs. The sand-sized minerals as additional sorbents increase the pool of easily mobilisable phosphorus in sediments, which will slow down the recovery of reservoir water due to its rapid re-mobilisation.

  20. Effect of Carbon on Grain Boundary Segregation of Phosphorus and Phosphorus-Induced Intergranular Fracture in High Purity Iron with Phosphorus

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The segregation of carbon at grain boundaries and its effect on phosphorus segregation and phosphorus-induced intergranular fracture in the alloy of high purity iron with phosphorus were investigated by scanning Auger electron spectroscopy, impact test and SEM observation of fractured surface. The experimental results showed that the carbon segregation at grain boundaries decreases the phosphorus segregation, and a change of fracture mode from intergranular fracture to transgranular one, hence a decrease of ductile-brittle transition temperature is observed. The mechanism of these effects was discussed.

  1. A model for microbial phosphorus cycling in bioturbated marine sediments: Significance for phosphorus burial in the early Paleozoic

    Science.gov (United States)

    Dale, Andrew W.; Boyle, Richard A.; Lenton, Timothy M.; Ingall, Ellery D.; Wallmann, Klaus

    2016-09-01

    A diagenetic model is used to simulate the diagenesis and burial of particulate organic carbon (Corg) and phosphorus (P) in marine sediments underlying anoxic versus oxic bottom waters. The latter are physically mixed by animals moving through the surface sediment (bioturbation) and ventilated by burrowing, tube-dwelling organisms (bioirrigation). The model is constrained using an empirical database including burial ratios of Corg with respect to organic P (Corg:Porg) and total reactive P (Corg:Preac), burial efficiencies of Corg and Porg, and inorganic carbon-to-phosphorus regeneration ratios. If Porg is preferentially mineralized relative to Corg during aerobic respiration, as many previous studies suggest, then the simulated Porg pool is found to be completely depleted. A modified model that incorporates the redox-dependent microbial synthesis of polyphosphates and Porg (termed the microbial P pump) allows preferential mineralization of the bulk Porg pool relative to Corg during both aerobic and anaerobic respiration and is consistent with the database. Results with this model show that P burial is strongly enhanced in sediments hosting fauna. Animals mix highly labile Porg away from the aerobic sediment layers where mineralization rates are highest, thereby mitigating diffusive PO43- fluxes to the bottom water. They also expand the redox niche where microbial P uptake occurs. The model was applied to a hypothetical shelf setting in the early Paleozoic; a time of the first radiation of benthic fauna. Results show that even shallow bioturbation at that time may have had a significant impact on P burial. Our model provides support for a recent study that proposed that faunal radiation in ocean sediments led to enhanced P burial and, possibly, a stabilization of atmospheric O2 levels. The results also help to explain Corg:Porg ratios in the geological record and the persistence of Porg in ancient marine sediments.

  2. Phosphorus Recycling from an Unexplored Source by Polyphosphate Accumulating Microalgae and Cyanobacteria-A Step to Phosphorus Security in Agriculture.

    Science.gov (United States)

    Mukherjee, Chandan; Chowdhury, Rajojit; Ray, Krishna

    2015-01-01

    Phosphorus (P), an essential element required for crop growth has no substitute. The global food security depends on phosphorus availability in soil for crop production. World phosphorus reserves are fast depleting and with an annual increase of 2.3% in phosphorus demand, the current reserves will be exhausted in coming 50-100 years. India and other Western countries are forced to import phosphorus fertilizers at high costs to meet their agricultural demands due to uneven distribution of phosphate rocks on earth. The present study from India, aims to draw attention to an unnoticed source of phosphorus being wasted as parboiled rice mill effluent and subsequent bio-recovery of the valuable element from this unconventional source. The research was conducted in West Bengal, India, a state with the highest number of parboiled rice mills where its effluent carries on an average ~40 mg/L of soluble phosphorus. Technology to recover and recycle this wastewater P in India in a simple, inexpensive mode is yet to be optimized. Our strategy to use microalgae, Chlorella sp. and cyanobacteria, Cyanobacterium sp., Lyngbya sp., and Anabaena sp. to sequester the excess phosphorus from the effluent as polyphosphate inclusions and its subsequent recycling as slow and moderate release phosphorus biofertilizers to aid plant growth, preventing phosphorus loss and pollution, is a contemporary venture to meet the need of the hour. These polyphosphate accumulating microorganisms play a dual role of remediation and recovery of phosphorus, preliminarily validated in laboratory scale. PMID:26733966

  3. Potential Impact of Dietary Choices on Phosphorus Recycling and Global Phosphorus Footprints: The Case of the Average Australian City

    Science.gov (United States)

    Metson, Geneviève S.; Cordell, Dana; Ridoutt, Brad

    2016-01-01

    Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world’s main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region’s “phosphorus footprint” – the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident’s annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management. PMID:27617261

  4. Potential Impact of Dietary Choices on Phosphorus Recycling and Global Phosphorus Footprints: The Case of the Average Australian City.

    Science.gov (United States)

    Metson, Geneviève S; Cordell, Dana; Ridoutt, Brad

    2016-01-01

    Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world's main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region's "phosphorus footprint" - the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident's annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management. PMID:27617261

  5. Phosphorus recycling from an unexplored source by polyphosphate accumulating microalgae and cyanobacteria – a step to phosphorus security in agriculture

    Directory of Open Access Journals (Sweden)

    Chandan eMukherjee

    2015-12-01

    Full Text Available Phosphorus (P, an essential element required for crop growth has no substitute. The global food security depends on phosphorus availability in soil for crop production. World phosphorus reserves are fast depleting and with an annual increase of 2.3% in phosphorus demand, the current reserves will be exhausted in coming 50-100 years. India and other Western countries are forced to import phosphorus fertilizers at high costs to meet their agricultural demands due to uneven distribution of phosphate rocks on earth. The present study from India, aims to draw attention to an unnoticed source of phosphorus being wasted as parboiled rice mill effluent and subsequent bio-recovery of the valuable element from this unconventional source. The research was conducted in West Bengal, India, a state with the highest number of parboiled rice mills where its effluent carries on an average ~40 mg/L of soluble phosphorus. Technology to recover and recycle this wastewater P in India in a simple, inexpensive mode is yet to be optimized. Our strategy to use microalgae, Chlorella sp. and cyanobacteria, Cyanobacterium sp., Lyngbya sp. and Anabaena sp. to sequester the excess phosphorus from the effluent as polyphosphate inclusions and its subsequent recycling as slow and moderate release phosphorus biofertilizers to aid plant growth, preventing phosphorus loss and pollution, is a contemporary venture to meet the need of the hour. These polyphosphate accumulating microorganisms play a dual role of remediation and recovery of phosphorus, preliminarily validated in laboratory scale.

  6. Elevated carbon dioxide increases soil nitrogen and phosphorus availability in a phosphorus-limited Eucalyptus woodland.

    Science.gov (United States)

    Hasegawa, Shun; Macdonald, Catriona A; Power, Sally A

    2016-04-01

    Free-air CO2 enrichment (FACE) experiments have demonstrated increased plant productivity in response to elevated (e)CO2, with the magnitude of responses related to soil nutrient status. Whilst understanding nutrient constraints on productivity responses to eCO2 is crucial for predicting carbon uptake and storage, very little is known about how eCO2 affects nutrient cycling in phosphorus (P)-limited ecosystems. Our study investigates eCO2 effects on soil N and P dynamics at the EucFACE experiment in Western Sydney over an 18-month period. Three ambient and three eCO2 (+150 ppm) FACE rings were installed in a P-limited, mature Cumberland Plain Eucalyptus woodland. Levels of plant accessible nutrients, evaluated using ion exchange resins, were increased under eCO2, compared to ambient, for nitrate (+93%), ammonium (+12%) and phosphate (+54%). There was a strong seasonality to responses, particularly for phosphate, resulting in a relatively greater stimulation in available P, compared to N, under eCO2 in spring and summer. eCO2 was also associated with faster nutrient turnover rates in the first six months of the experiment, with higher N (+175%) and P (+211%) mineralization rates compared to ambient rings, although this difference did not persist. Seasonally dependant effects of eCO2 were seen for concentrations of dissolved organic carbon in soil solution (+31%), and there was also a reduction in bulk soil pH (-0.18 units) observed under eCO2. These results demonstrate that CO2 fertilization increases nutrient availability - particularly for phosphate - in P-limited soils, likely via increased plant belowground investment in labile carbon and associated enhancement of microbial turnover of organic matter and mobilization of chemically bound P. Early evidence suggests that there is the potential for the observed increases in P availability to support increased ecosystem C-accumulation under future predicted CO2 concentrations. PMID:26546164

  7. ِDetermining the Efficiency of WWTP in Khoy Power Plant and Improving Phosphorus Removal by Anoxic-Oxic Process

    OpenAIRE

    A.R Mesdaginia; M Aganeghad; F Vaezi

    2009-01-01

    "n "nBackgrounds and Objectives: Now a days modified activated sludge ways are used for standard removing nutrient substances from waste water that is named Enhanced biological phosphorus removal One of the most suitable ways is Anoxic-Oxic(A/O) process. The goal of this research is investigation and solving existing problems of Khoy power plant(P.P) waste water treatment plant(WWTP)and optimizing of phosphorus removal in it."nMaterials and Methods: This research is done full scale in this tr...

  8. [Radioactivity of phosphorus implanted TiNi alloy].

    Science.gov (United States)

    Zhao, Xingke; Cai, Wei; Zhao, Liancheng

    2003-09-01

    Exposed to neutron flow, the phosphorus implanted TiNi alloy gets radioactive. This radioactive material is used in vascular stent for prevention and cure of restenosis. Phosphorus implantation is carried out in a plasma immerged ion implantation system, and the dose of phosphorus implantation is in the range of 2-10 x 10(17) cm-2. After ion implantation, the alloy is exposed to the slow neutron flow in a nuclear reactor, the dose of the slow neutron is 1.39-5.88 x 10(19) n/cm2. The radioactivity of the TiNi alloy was measured by liquid scintillation spectrometry and radio-chromic-film dosimetry. The result shows that whether the phosphorus is implanted or not, the TiNi alloy comes to be radioactive after exposure to neutron flow. Just after neutron irradiation, the radiation dose of phosphorus implanted TiNi alloy is about one hundred times higher than that of un-phosphorus implanted TiNi alloy. The radiation difference between phosphorus and un-phosphorus implanted alloy decreases as time elapses. Within three months after neutron irradiation, the average half-decay period of phosphorus implanted TiNi alloy is about 62 days. The radiation ray penetration of phosphorus implanted TiNi alloy is deeper than that of pure 32P; this is of benefit to making radiation uniformity between stent struts and reducing radiation grads beyond the edge of stent.

  9. Rhizosphere effect of different aquatic plants on phosphorus depletion

    Institute of Scientific and Technical Information of China (English)

    Zhenyu WANG; Shengfang WEN; Baoshan XING; Dongmei GAO; Fengmin LI

    2008-01-01

    A series of pot experiments with Alternanthera philoxeroides, Typha latifolia, Sagittaria sagittifolia and Phragmites communis were conducted to assess the phos-phorus depletion effect in the rhizosphere. The ratio of root to shoot, root morphology, phosphorus uptake efficiency and phosphorus utilization efficiency were analyzed. An obvious variation in phosphorus concentrations between the rhizosphere soil and non-rhizosphere soil was observed. The water-soluble P contents in the rhizosphere soil of A. philoxeroides, T. latifolia, S. sagittifolia and P. communis were reduced by 81%, 42%, 18% and 16%, respectively, compared with that in the non-rhizosphere soil. A. philox-eroides had the highest phosphorus uptake efficiency (1.32 mg/m), while T. latifolia achieved the effective phos-phorus depletion by the strong rooting system and the high phosphorus uptake efficiency (0.52 mg/m). T. latifolia not only used phosphorus to produce biomass economically, but also adjusted carbon allocation to the roots to explore the soil for more available phosphorus. A. philoxeroides and T. latifolia were more effective in depleting phosphorus in the rhizosphere than S. sagittifolia and P. communis.

  10. Landslide-induced changes in soil phosphorus speciation and availability in Xitou, Central Taiwan

    Science.gov (United States)

    Cheng, Chih-Hsin; Hsiao, Sheng-Che; Huang, Yu-Sheng; Chen, Chiu-Ping; Menyailo, Oleg

    2016-04-01

    Phosphorus is an important nutrient in forest ecosystem. In tropical/subtropical areas, phosphorus is generally limited because of strong soil weathering but its speciation and availability can be changed by disturbances, such as the geological landslide events. In this study, we evaluated the changes in soil P speciation and availability after landslide in a mountainous forest ecosystem in Xitou, central Taiwan. Five soil pedons along a landslide/nonlanslide affected sequence from deep landslide deposit to nonlandslide were collected. The Hedley's sequential extraction procedure and synchrotron-based phosphorus x-ray adsorption near edge structure (XANES) spectroscopy were applied for the surface 0-10 cm and 10-20 cm soils to provide information concerning chemical and structural composition of phosphorus. The results indicated that plant available P (Resin-P + NaHCO3 extract P) and total P were reduced after landslide, from 150 and 500 mg kg-1, respectively, at nonlandsliding sites to 50 and 350 mg kg-1 at landsliding sites. However, the apatite-type P was significantly increased after landslide, from about 70 mg kg-1 at nonlandsliding sites to around 200 mg kg-1 at landsliding sites. Similar trend of enhanced apatite-type P after landslide was also observed in the XANES spectra. The ryegrass pot experiment confirmed that the landsliding soils were less fertile and had less growth rate. However, both nitrogen and phosphorus nutrients were limited at landsliding sites. The results demonstrated that soil P speciation and availability were significantly altered after landslide; these resultant changes are expected to influence functions in forest ecosystems.

  11. Regulating phosphorus from the agricultural sector

    DEFF Research Database (Denmark)

    Hansen, Line Block; Hansen, Lars Gårn; Rubæk, Gitte Holton

    2010-01-01

    do not take into account the importance of P already stored in the soils. Phosphorus stored in the soils is the major source of P losses to surface waters, but at the same time crucial for the soils ability to sustain a viable crop production. Even if measures on P losses from agricultural areas...... could be obtained, such measures may not truly reflect stocks and hence potential risks associated with eg erosion, run-off or climate change. This calls for a method which handles the continuous supply of P to the soils (the current flow effect), P accumulated in the soil (a stock effect......  Loss of phosphorus (P) from agricultural areas is one of the main contributors to eutrophication of water systems in many European countries. Regulatory systems such as ambient taxes or discharge taxes which are suitable for regulation of N are insufficient for regulating P because these systems...

  12. SYNTHESIS AND CHARACTERIZATION OF POLYBENZOXAZINE CONTAINING PHOSPHORUS

    Institute of Scientific and Technical Information of China (English)

    Ting-ting Zhang; Wei-wei Men; Ying Liu; Zai-jun Lu

    2012-01-01

    The novel benzoxazine monomer containing phosphorus has been synthesized based on multifunctional amine route from bis(4-aminophenyl)phenylphosphate,p-cresol and formaldehyde.Subsequently,the benzoxazine monomer was thermo-cured into polybenzoxazine containing phosphorus.The chemical structures were identified by nuclear magnetic resonance (NMR),Fourier transform infrared spectroscopy (FT-IR).The curing reaction was monitored by differential scanning calorimetry (DSC) and FT-IR.The thermal and flame-retardant properties of obtained polybenzoxazine were evaluated by dynamic mechanical thermal analysis (DMA),thermal gravimetric analysis (TGA) and oxygen index meter,respectively.The results show that the novel polybenzoxazine has high limiting oxygen index (38.1) and glass transition temperature (232℃).

  13. Peak phosphorus - peak food? The need to close the phosphorus cycle.

    Science.gov (United States)

    Rhodes, Christopher J

    2013-01-01

    The peak in the world production of phosphorus has been predicted to occur in 2033, based on world reserves of rock phosphate (URR) reckoned at around 24,000 million tonnes (Mt), with around 18,000 Mt remaining. This figure was reckoned-up to 71,000 Mt, by the USGS, in 2012, but a production maximum during the present century is still highly probable. There are complex issues over what the demand will be for phosphorus in the future, as measured against a rising population (from 7 billion to over 9 billion in 2050), and a greater per capita demand for fertiliser to grow more grain, in part to feed animals and meet a rising demand for meat by a human species that is not merely more populous but more affluent. As a counterweight to this, we may expect that greater efficiencies in the use of phosphorus - including recycling from farms and of human and animal waste - will reduce the per capita demand for phosphate rock. The unseen game changer is peak oil, since phosphate is mined and recovered using machinery powered by liquid fuels refined from crude oil. Hence, peak oil and peak phosphorus might appear as conjoined twins. There is no unequivocal case that we can afford to ignore the likelihood of a supply-demand gap for phosphorus occurring sometime this century, and it would be perilous to do so.

  14. Low phosphorus tolerance mechanisms: phosphorus recycling and photosynthate partitioning in the tropical forage grass, Brachiaria hybrid cultivar Mulato compared with rice.

    Science.gov (United States)

    Nanamori, Masahito; Shinano, Takuro; Wasaki, Jun; Yamamura, Takuya; Rao, Idupulapati M; Osaki, Mitsuru

    2004-04-01

    The Brachiaria hybrid cv. Mulato is well adapted to low-fertility acid soils deficient in phosphorus (P). To study the grassy forage's mechanisms for tolerating low P supply, we compared it with rice (Oryza sativa L. cv. Kitaake). We tested by using nutrient solution cultures, and quantified the effects of P deficiency on the enzymatic activities of phosphohydrolases and on carbon metabolism in P-deficient leaves. While P deficiency markedly induced activity of phosphohydrolases in both crops, the ratio of inorganic phosphorus to total P in leaves was greater in Brachiaria hybrid. Phosphorus deficiency in leaves also markedly influenced the partitioning of carbon in both crops. In the Brachiaria hybrid, compared with rice, the smaller proportion of (14)C partitioned into sugars and the larger proportion into amino acids and organic acids in leaves coincided with decreased levels of sucrose and starch. Hence, in P-deficient leaves of the Brachiaria hybrid, triose-P was metabolized into amino acids or organic acids. Results thus indicate that the Brachiaria hybrid, compared with rice, tolerates low P supply to leaves by enhancing sugar catabolism and by inducing the activity of several phosphohydrolases. This apparently causes rapid P turnover and enables the Brachiaria hybrid to use P more efficiently. PMID:15111721

  15. Isolation and Identification of Phosphate-accumulating Strain PAO3-1 and Its Phosphorus Removal Characteristics

    Institute of Scientific and Technical Information of China (English)

    LIU Ya-nan; XUE Gang; SHI Feng-hua; YU Shui-li

    2007-01-01

    A phosphate-accumulating bacteria strain PAO3-1 was isolated from biological phosphorus removal sludge supplied with sodium acetate as carbon source under stable performance. This strain has good enhanced biological phosphorus removal effect on normal activated sludge system. Phosphorus removal ratio was raised form 44%with no added strain to more than 82% with strain strengthening biological phosphorus removal. It is identified to be AlcaUgenes sp. according to its morphology,biochemical characteristics and 16S rDNA sequence analysis. The cell of strain PAO3-1 is straight bacilli form, 0.4×1.1 μm, no flagellum, gram negative and special aerobiotic. The optimal temperature and pH for growth are 32℃-37℃ and 5.5-9.5, respectively. The shape of slant clone is feathery. The phosphate situation, which was 76. 5% higher than that in non-starving situation. Its phosphate release rate of log course in anaerobic phase and in culture without phosphorus was lower than that in log course.

  16. Initial and residual effects of fertilizer phosphorus on soil phosphorus and maize yields on phosphorus fixing soils. A case study in south-west Kenya

    NARCIS (Netherlands)

    Eijk, van der D.; Janssen, B.H.; Oenema, O.

    2006-01-01

    The objective of this article is to provide experimental data and new insights about the best P fertilization strategy for phosphorus (P) fixing soils in the tropics. Two controversial strategies to manage soils with high phosphorus (P) fixation capacity were compared with regard to effects on maize

  17. Distribution behavior of phosphorus in the coal-based reduction of high-phosphorus-content oolitic iron ore

    Institute of Scientific and Technical Information of China (English)

    Yong-sheng Sun; Yue-xin Han; Peng Gao; Duo-zhen Ren

    2014-01-01

    This study focuses on the reduction of phosphorus from high-phosphorus-content oolitic iron ore via coal-based reduction. The distribution behavior of phosphorus (i.e., the phosphorus content and the phosphorus distribution ratio in the metal, slag, and gas phases) during reduction was investigated in detail. Experimental results showed that the distribution behavior of phosphorus was strongly influenced by the reduction temperature, the reduction time, and the C/O molar ratio. A higher temperature and a longer reaction time were more favor-able for phosphorus reduction and enrichment in the metal phase. An increase in the C/O ratio improved phosphorus reduction but also hin-dered the mass transfer of the reduced phosphorus when the C/O ratio exceeded 2.0. According to scanning electron microscopy analysis, the iron ore was transformed from an integral structure to metal and slag fractions during the reduction process. Apatite in the ore was reduced to P, and the reduced P was mainly enriched in the metal phase. These results suggest that the proposed method may enable utilization of high-phosphorus-content oolitic iron ore resources.

  18. Closing the Phosphorus Loop by Recovering Phosphorus From Waste Streams With Layered Double Hydroxide Nanocomposites and Converting the Product into an Efficient Fertilizer

    Science.gov (United States)

    Yan, H.; Shih, K.

    2015-12-01

    Phosphorus (P) recovery has been frequently discussed in recent decades due to the uncertain availability and uneven distribution of global phosphate rock reserves. Sorption technology is increasingly considered as a reliable, efficient and environmentally friendly P removal method from aqueous solution. In this study, a series of Mg-Al-based layered double hydroxide nanocomposites and their corresponding calcined products were fabricated and applied as phosphate adsorbents. The prepared samples were with average size at ~50 nm and self-assembled into larger particles in irregular shapes. The results of batch adsorption experiments demonstrated that calcination significantly enhanced the adsorption ability of LDHs for phosphorus, and the maximum adsorption capacity of calcined Mg-Al-LDH was as high as 100.7 mg-P/g. Furthermore, incorporation of Zr4+ and La3+ into LDH materials increases the sorption selectivity as well as sorption amount of phosphorus in LDHs, which was confirmed by experiments operated in synthetic human urine. For the first time ammonia (NH4OH) and potassium hydroxide (KOH) solutions were employed to desorb the P-loaded LDH. Identification of solids derived from two eluting solutions showed that struvite (MgNH4PO4•6H2O, MAP) was precipitated in ammonia solution while most phosphate was desorbed into liquid phase in KOH system without crystallization of potassium struvite (MgKPO4•6H2O) due to its higher solubility. Quantitative X-ray diffraction technique was used to determine struvite contents in obtained solids and the results revealed that ~ 30% of adsorbed P was transferred into struvite form in the sample extracted by 0.5M NH4OH. Leaching tests suggested that the phosphorus releasing kinetics of ammonia treated LDH was comparable to that of pure struvite product, indicating that postsorption Mg-Al-LDH desorbed with ammonia could serve as a slow-releasing fertilizer in agriculture (see Figure 1).

  19. Biological phosphorus uptake under anoxic and aerobic conditions

    DEFF Research Database (Denmark)

    Kerrn-Jespersen, Jens Peter; Henze, Mogens

    1993-01-01

    Biological phosphorus removal was investigated under anoxic and aerobic conditions. Tests were made to establish whether phosphorus accumulating bacteria can take up phosphate under anoxic conditions and thus utilise nitrate as oxidant. Furthermore, it was tested how the amount of organic matter...... sludge from two different pilot plants incorporating phosphorus removal. The results showed that the phosphorus accumulating bacteria can be divided into two groups in respect of process; one group capable of utilising only oxygen as oxidant and another group capable of utilising both oxygen and nitrate...... taken up by the phosphorus accumulating bacteria during the anaerobic phase affects the total denitrification rate, as well as the rate at which the phosphorus accumulating bacteria take up phosphate under anoxic conditions. The tests were conducted as batch experiments in 21. reactors with activated...

  20. Attaining 2D Black Phosphorus and Investigations into Floating-Electrode Dielectric Barrier Discharge Treatment of Solutions

    Science.gov (United States)

    Smith, Joshua Benjamin

    -ray diffraction, transmission electron microscopy, and Raman spectroscopy have confirmed successful growth of 2D black phosphorus from red phosphorus thin films for potential uses in 2D semiconductor applications. Additionally, this work discusses some of the chemistry occurring in solution as a result of nonthermal plasma treatment from a floating-electrode dielectric barrier discharge (FE-DBD) configuration. Nonthermal plasma generation allows for the treatment of heat sensitive materials. This has opened up the field to numerous clinical applications of nonthermal plasma treatment including sterilization and wound healing along with potentials in dentistry, dermatology, and even food industries. FE-DBD plasma treatment of water was found to provide a wide-range antimicrobial solution that remained active following 2 years of aging. This plasma-treated water was found to generate a number of ROS/RNS and the formation of these components was studied and verified with UV/Vis and ESR spectroscopy. Enhanced effects were observed when cell culture medium was plasma treated, suggesting the formation of additional reactive species from the plasma treatment of a variety of biomolecules. It is essential to understand these effects for a number of reasons. The possibility to generate a wide range of antimicrobial solutions from air, water, and basic biomolecules could provide a solution for those bacteria that have developed antibiotic resistances. Simultaneously, information into the reaction mechanisms of this FE-DBD plasma treatment can be investigated. All of the applications mentioned above involve complex networks of basic biomolecules, from skin tissue to bacteria cell walls. This work analyzes the effects of plasma treatment on several biomolecule solutions and simultaneously takes aim at understanding some of the potential mechanisms of plasma treatment. Studies were carried out using NMR and GC/MS. This information was used to investigate the possible targeted areas for FE

  1. Metabolism of nonparticulate phosphorus in an acid bog lake

    Energy Technology Data Exchange (ETDEWEB)

    Koenings, J. P.

    1977-01-01

    In North Gate Lake, an acid bog lake located on the northern Michigan-Wisconsin border, U.S.A., the algal nutrient inorganic phosphate (FRP) is not detectable by chemical means. Organic phosphorus (FUP) represents 100% of the detectable filterable phosphorus. The availability and cycling of this organic fraction are of considerable interest in regard to the primary productivity of this system. To clarify these relationships, the cycling of nonparticulate forms of phosphorus found in the epilimnion of this lake was studied.

  2. The Modern Phosphorus Sustainability Movement: A Profiling Experiment

    OpenAIRE

    Andrea E. Ulrich; Ewald Schnug

    2013-01-01

    Since the “peak phosphorus†concept emerged in 2007, concerns about the future availability of phosphate rock have funneled into a growing number of actions, often in the form of new and innovative platforms focusing on phosphorus sustainability. This trend seems to continue on different levels and in different formats, which makes the landscape of activities increasingly blurred and complex. This article considers the emerging phase of the modern phosphorus sustainability movement. It pro...

  3. Isotopic fingerprint for phosphorus in drinking water supplies

    OpenAIRE

    Gooddy, Daren C.; Lapworth, Dan J.; Ascott, Matthew J.; Sarah A Bennett; Heaton, Timothy H.E.; Surridge, Ben W.J.

    2015-01-01

    Phosphate dosing of drinking water supplies, coupled with leakage from distribution networks, represents a significant input of phosphorus to the environment. The oxygen isotope composition of phosphate (δ18OPO4), a novel stable isotope tracer for phosphorus, offers new opportunities to understand the importance of phosphorus derived from sources such as drinking water. We report the first assessment of δ18OPO4 within drinking water supplies. A total of 40 samples from phosphate-dosed distrib...

  4. Eutrophication of aquatic ecosystems: Bistability and soil phosphorus

    OpenAIRE

    Stephen R Carpenter

    2005-01-01

    Eutrophication (the overenrichment of aquatic ecosystems with nutrients leading to algal blooms and anoxic events) is a persistent condition of surface waters and a widespread environmental problem. Some lakes have recovered after sources of nutrients were reduced. In others, recycling of phosphorus from sediments enriched by years of high nutrient inputs causes lakes to remain eutrophic even after external inputs of phosphorus are decreased. Slow flux of phosphorus from overfertilized soils ...

  5. Metabolism of nonparticulate phosphorus in an acid bog lake

    International Nuclear Information System (INIS)

    In North Gate Lake, an acid bog lake located on the northern Michigan-Wisconsin border, U.S.A., the algal nutrient inorganic phosphate (FRP) is not detectable by chemical means. Organic phosphorus (FUP) represents 100% of the detectable filterable phosphorus. The availability and cycling of this organic fraction are of considerable interest in regard to the primary productivity of this system. To clarify these relationships, the cycling of nonparticulate forms of phosphorus found in the epilimnion of this lake was studied

  6. Phosphorus speciation in sediments of Lake Hongfeng, China

    Institute of Scientific and Technical Information of China (English)

    JIANG Cuihong; HU Jiwei; HUANG Xianfei; LI Cunxiong; DENG Jiajun; ZHANG Jie; LIU Feng

    2011-01-01

    This study was conducted to evaluate the distribution characteristics of phosphorus and its species in 14 sediments samples collected from Lake Hongfeng based on sequential extraction. Lake Hongfeng, a major drinking-water source for Guiyang City in southwestern China, is one of the largest artificial reservoirs located in a typical karstic area of the Yunnan-Guizhou Plateau. The results of this study indicate that the average percentages of DP, Al-P, Fe-P, Ca-P and OP in the lake sediments were 0.52, 6.59, 6.09, 42.85 and 40.27, respectively. The concentrations of organic phosphorus (OP) were lower than those of inorganic phosphorus (IP), which consisted mainly of calcium-bound phosphorus (Ca-P). The high concentrations of Ca-P may temporarily control the release of phosphorus from the sediments because it is a relatively stable, inert, and non-bioavailable phosphorus fraction. However, a large number of phosphate solubilizing bacteria can transform insoluble phosphate into bioavailable forms. Moreover, the concentrations of total phosphorus (TP) in the lake sediments were high; thus, the potential for the release of phosphorus from the sediments to the water column and phosphorus bioavailability were still significant. Further statistical analyses of the results revealed significant correlations between phosphorus species in sediments from the lake with two extractable principal component species (PCs) and five selectable cluster levels allowing interpretation of possible origins of phosphorus loading and the release of phosphorus. Furthermore, available remediation measures were briefly assessed for the lake with consideration of its distinctive environmental features.

  7. Importance of Farm Phosphorus Mass Balance and Management Options

    OpenAIRE

    Maguire, Rory

    2014-01-01

    Phosphorus is a naturally occurring element that is one of 16 elements essential for plant growth and animal health. Research has documented that applying phosphorus in fertilizers or manure increases crop growth and yield on soils that are below critical agronomic levels, as measured during routine soil testing. Although the economic benefits of phosphorus fertilization on crop production are well-documented, too much of a good thing can be detrimental to the environment. Excessive soil phos...

  8. Resource recovery from wastewater: application of meta-omics to phosphorus and carbon management.

    Science.gov (United States)

    Sales, Christopher M; Lee, Patrick K H

    2015-06-01

    A growing trend at wastewater treatment plants is the recovery of resources and energy from wastewater. Enhanced biological phosphorus removal and anaerobic digestion are two established biotechnology approaches for the recovery of phosphorus and carbon, respectively. Meta-omics approaches (meta-genomics, transcriptomics, proteomics, and metabolomics) are providing novel biological insights into these complex biological systems. In particular, genome-centric metagenomics analyses are revealing the function and physiology of individual community members. Querying transcripts, proteins and metabolites are emerging techniques that can inform the cellular responses under different conditions. Overall, meta-omics approaches are shedding light into complex microbial communities once regarded as 'blackboxes', but challenges remain to integrate information from meta-omics into engineering design and operation guidelines. PMID:25827118

  9. ESR studies of high-energy phosphorus-ion implanted synthetic diamond crystals

    Energy Technology Data Exchange (ETDEWEB)

    Isoya, J. [University of Library and Information Science, Tsukuba, Ibaraki (Japan); Kanda, H.; Morita, Y.; Ohshima, T.

    1997-03-01

    Phosphorus is among potential n-type dopants in diamond. High pressure synthetic diamond crystals of type IIa implanted with high energy (9-18 MeV) phosphorus ions have been studied by using electron spin resonance (ESR) technique. The intensity and the linewidth of the ESR signal attributed to the dangling bond of the amorphous phase varied with the implantation dose, suggesting the nature of the amorphization varies with the dose. The ESR signals of point defects have been observed in the low dose as-implanted crystals and in the high dose crystals annealed at high temperature and at high pressure. (author)

  10. Phosphorus limitation in biofiltration for drinking water treatment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Bacterial growth potential(BGP) method and two parallel pilot-scale biofilters were used to investigate phosphorus limitation and itseffect on the removal of organic matters in biofiltration for drinking water treatment. Addition of phosphorus can substantially increase the BGPsof the samples. Its effect was equivalent to that of addition of a mixture of various inorganic nutrients including phosphorus. The biofilter withphosphate added into its influent performed a higher biological stability of the effluent and a higher CODMn removal than the control filter. Theseresults suggested that phosphorus was the limiting nutrient in the biofiltration and the removal efficiency of organic matters could be improved byadding phosphate into the influent.

  11. Phosphorus removal from domestic wastewater by Echinodorus cordifolius L.

    Science.gov (United States)

    Torit, Jirawan; Siangdung, Wipawan; Thiravetyan, Paitip

    2012-01-01

    This study was to use the plants to remove phosphorus from domestic wastewater which contained high phosphorus concentration. Six higher plant species such as Crinum asiaticum L., Echinodorus cordifolius L., Spathiphyllum clevelandii Schott, Rhizophora apiculata Blume, Thalia dealbata J.fraser., Heliconia psittacorum L.f. were screened for phosphorus removal. Plants were grown in the domestic wastewater and the remaining phosphorus-phosphate concentration in the systems was determined. The results indicated that among studied plants, Echinodorus cordifolius L. was the best for phosphorus removal. Using this plant will improve the quality of domestic wastewater which contained excess phosphorus concentration and induced eutrophication. The relationship between the plants, microorganisms, and soil in the system were also investigated. In this system, adsorption by soil was the major role for phosphorus removal (71%), followed by E. cordifolius (16%), microorganisms in domestic wastewater (7%), and microorganisms in soil (6%). These results indicated the ability of E. cordifolius to remove phosphorus which was superior to that of the microorganisms in the system. Moreover, the rapid phosphorus removal was concomitant to the growth, photosynthesis activity and biomass of E. cordifolius grown in domestic wastewater. The C:N:P ratio of E. cordifolius tissue in the system indicated that elements were taken up from the wastewater. From these results, the suitability of E. cordifolius for domestic wastewater treatment was confirmed.

  12. Phosphorus removal from domestic wastewater by Echinodorus cordifolius L.

    Science.gov (United States)

    Torit, Jirawan; Siangdung, Wipawan; Thiravetyan, Paitip

    2012-01-01

    This study was to use the plants to remove phosphorus from domestic wastewater which contained high phosphorus concentration. Six higher plant species such as Crinum asiaticum L., Echinodorus cordifolius L., Spathiphyllum clevelandii Schott, Rhizophora apiculata Blume, Thalia dealbata J.fraser., Heliconia psittacorum L.f. were screened for phosphorus removal. Plants were grown in the domestic wastewater and the remaining phosphorus-phosphate concentration in the systems was determined. The results indicated that among studied plants, Echinodorus cordifolius L. was the best for phosphorus removal. Using this plant will improve the quality of domestic wastewater which contained excess phosphorus concentration and induced eutrophication. The relationship between the plants, microorganisms, and soil in the system were also investigated. In this system, adsorption by soil was the major role for phosphorus removal (71%), followed by E. cordifolius (16%), microorganisms in domestic wastewater (7%), and microorganisms in soil (6%). These results indicated the ability of E. cordifolius to remove phosphorus which was superior to that of the microorganisms in the system. Moreover, the rapid phosphorus removal was concomitant to the growth, photosynthesis activity and biomass of E. cordifolius grown in domestic wastewater. The C:N:P ratio of E. cordifolius tissue in the system indicated that elements were taken up from the wastewater. From these results, the suitability of E. cordifolius for domestic wastewater treatment was confirmed. PMID:22416873

  13. Determination of phosphorus in hypereutectic aluminium-silicon alloys.

    Science.gov (United States)

    Mukai, K

    1972-04-01

    A reproducible method is described for determination of small amounts of phosphorus (from 0.0005% to 0.02%) in hypereutectic aluminium-silicon complex alloys. The method permits the separate determination of phosphorus in acid-soluble and acid-insoluble fractions. Phosphomolybdate is extracted with n-butanol-chloroform solvent mixture and back-extracted with a btannous chloride reducing solution. The phosphorus content of a sample cut into small pieces decreases during storage; loss of phosphorus is negligible on acid dissolution under oxidizing conditions. PMID:18961077

  14. [Dynamic change of phosphorus leaching of neutral purple soil at different re-wetting rate].

    Science.gov (United States)

    Zhang, Si-Lan; Shi, Xiao-Jun; Guo, Tao

    2014-03-01

    Re-wetting was one of the most common forms of abiotic stresses experienced by soils. To investigate the effects of soil re-wetting rate on phosphorus (P) leaching and the relationship between soil microbial biomass carbon (MBC) and forms of P in leachate; five kinds of neutral purple soils of different fertilizer treatments were analyzed using simulating lab test at re-wetting rate of 0 h, 2 h, 4 h, 24 h and 48 h. The results showed that: (1) The lowest content of MBC appeared at the rate of 2 h during the soil re-wetting process, and the content of MBC increased with the reducing re-wetting rate. (2) Slower re-wetting helped to enhance soil microbial activity and the enhancement effect of organic fertilizer with NPK fertilizer (MNPK) was more significant. (3) The P leaching events of all fertilizer treatments occurred mainly at rapid re-wetting rates such as 0 h, 2 h, 4 h. Slower re-wetting was an important measure to prevent P leaching especially for the soils applied with chemical fertilizers, and it was of great significance in the field management of P. (4) Dissolved organic phosphorus (DOP) was the primary leaching part in leachate, and the variation range of ratio of total dissolved phosphorus (TDP) to total phosphorus (TP) and DOP to TP was 35.42%-85.99% and 29.74%-78.58% respectively. (5) With the reducing of re-wetting rate, significant negative correlation was observed between MBC and TP, TDP as well as DOP in the leachate (P < 0.05). To sum up, it was speculated that the P in soil leachate mainly came from soil microorganisms. PMID:24881404

  15. Opportunities for improving phosphorus-use efficiency in crop plants.

    Science.gov (United States)

    Veneklaas, Erik J; Lambers, Hans; Bragg, Jason; Finnegan, Patrick M; Lovelock, Catherine E; Plaxton, William C; Price, Charles A; Scheible, Wolf-Rüdiger; Shane, Michael W; White, Philip J; Raven, John A

    2012-07-01

    Limitation of grain crop productivity by phosphorus (P) is widespread and will probably increase in the future. Enhanced P efficiency can be achieved by improved uptake of phosphate from soil (P-acquisition efficiency) and by improved productivity per unit P taken up (P-use efficiency). This review focuses on improved P-use efficiency, which can be achieved by plants that have overall lower P concentrations, and by optimal distribution and redistribution of P in the plant allowing maximum growth and biomass allocation to harvestable plant parts. Significant decreases in plant P pools may be possible, for example, through reductions of superfluous ribosomal RNA and replacement of phospholipids by sulfolipids and galactolipids. Improvements in P distribution within the plant may be possible by increased remobilization from tissues that no longer need it (e.g. senescing leaves) and reduced partitioning of P to developing grains. Such changes would prolong and enhance the productive use of P in photosynthesis and have nutritional and environmental benefits. Research considering physiological, metabolic, molecular biological, genetic and phylogenetic aspects of P-use efficiency is urgently needed to allow significant progress to be made in our understanding of this complex trait.

  16. Effect of phytase supplementation on apparent phosphorus digestibility and phosphorus output in broiler chicks fed low-phosphorus diets

    Directory of Open Access Journals (Sweden)

    Xian-Ren Jiang

    2015-04-01

    Full Text Available This study was conducted to evaluate the effect of supplemental phytase in broiler chicks fed different low levels of total phosphorus (P on the apparent phosphorus digestibility (APD and phosphorus output (PO in the faeces and ileal digesta. After fed a standard broiler starter diet from day 0 to 14 post-hatch, a total of 144 male broiler chicks were allocated to 6 groups for a 7-d experiment with a 2 × 3 factorial design comparing phytase (supplemented without (CTR or with 400 FTU/kg phytase (PHY and total P levels (2.0, 2.5 and 3.0 g/kg. The faecal samples were collected from day 17 to 21 post-hatch. At 22 days of age, all the chicks were slaughtered and collected the ileal digesta. Phytase supplementation significantly (P < 0.01 increased APD and decreased PO in the faeces and ileal digesta in comparison with the CTR group. In addition, PO in the faeces expressed as g/kg DM diets and faeces (Diet × P level, P = 0.047 and < 0.01, respectively as well as PO in the ileal digesta expressed as g/kg DM digesta (Diet × P level, P = 0.04 were affected by diet and P level, which were due to the significant reduction (P < 0.01 by PHY supplementation to the diets with 3.0 g/kg total P. The results evidenced that supplemental phytase improved the APD and PO when chicks was fed 3.0 g/kg total P diet, while lower total P levels may limit exogenous phytase efficacy.

  17. Effect of mycorrhiza on growth criteria and phosphorus nutrition of lettuce (Lactuca sativa L. under different phosphorus application rates

    Directory of Open Access Journals (Sweden)

    S. Fatih Ergin

    2016-10-01

    Full Text Available In this study, effect of mycorrhiza on growth criteria and phosphorus nutrition of lettuce (Lactuca sativa L. under different phosphorus fertilization rates were investigated. Phosphorus were added into growing media as 0, 50, 100 and 200 mg P2O5/kg with and without mycorrhiza applications. Phosphorus applications significantly increased yield criteria of lettuce according to the control treatment statistically. Mycorrhiza application also significantly increased plant diameter, plant dry weight and phosphor uptake by plant. The highest phosphorus uptakes by plants were determined in 200 mg P2O5/kg treatments as 88.8 mg P/pot with mycorrhiza and 83.1 mg P/pot without mycorrhiza application. In the control at 0 doses of phosphorus with mycorrhiza treatment, phosphorus uptake (69.9 mg P/pot, edible weight (84.36 g, dry weight (8.64 g and leaf number (28 of lettuce were higher than that (47.7 mg P/pot, 59.33 g, 6.75 g and 20, respectively in the control without mycorrhiza application. It was determined that mycorrhiza had positive effect on growth criteria and phosphorus nutrition by lettuce plant, and this effect decreased at higher phosphorus application rates.

  18. Regional Substance Flow Analysis for Assessment of Long-term Phosphorus Accumulation in Soil

    OpenAIRE

    Zabrodina, Marina Vladimirovna

    2013-01-01

    Phosphorus is a non-renewable resource that is essential for food production. At the same time, phosphorus may cause environmental problems because excess phosphorus in agricultural soil often leads to eutrophication. For rational and sound phosphorus management in order to mitigate resource scarcity and eutrophication problems, reliable estimates of phosphorus pools and flows and the understanding of phosphorus soil dynamics are needed. Studies in Material Flow Analysis that consider soil ph...

  19. Numerical Simulation of Phosphorus Removal from Silicon by Induction Vacuum Refining

    Science.gov (United States)

    Zheng, Songsheng; Engh, Thorvald Abel; Tangstad, Merete; Luo, Xue-Tao

    2011-08-01

    Phosphorus can be expected to evaporate preferentially from silicon melt by induction vacuum refining (IVR). In the present study, on the assumption of phosphorus evaporating from silicon melt as gas species P and P 2, a numerical model of phosphorus removal from silicon by IVR was developed. The factors affecting phosphorus removal in decreasing order are temperature, chamber pressure, geometry of silicon melt, holding time, and original phosphorus concentration. Calculated phosphorus removal shows good agreement with the present experimental data.

  20. Patient education for phosphorus management in chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Kalantar-Zadeh K

    2013-05-01

    Full Text Available Kamyar Kalantar-ZadehHarold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California Irvine’s School of Medicine, Irvine, CA, USAObjectives: This review explores the challenges and solutions in educating patients with chronic kidney disease (CKD to lower serum phosphorus while avoiding protein insufficiency and hypercalcemia.Methods: A literature search including terms “hyperphosphatemia,” “patient education,” “food fatigue,” “hypercalcemia,” and “phosphorus–protein ratio” was undertaken using PubMed.Results: Hyperphosphatemia is a strong predictor of mortality in advanced CKD and is remediated via diet, phosphorus binders, and dialysis. Dietary counseling should encourage the consumption of foods with the least amount of inorganic or absorbable phosphorus, low phosphorus-to-protein ratios, and adequate protein content, and discourage excessive calcium intake in high-risk patients. Emerging educational initiatives include food labeling using a “traffic light” scheme, motivational interviewing techniques, and the Phosphate Education Program – whereby patients no longer have to memorize the phosphorus content of each individual food component, but only a “phosphorus unit” value for a limited number of food groups. Phosphorus binders are associated with a clear survival advantage in CKD patients, overcome the limitations associated with dietary phosphorus restriction, and permit a more flexible approach to achieving normalization of phosphorus levels.Conclusion: Patient education on phosphorus and calcium management can improve concordance and adherence and empower patients to collaborate actively for optimal control of mineral metabolism.Keywords: hyperphosphatemia, renal diet, phosphorus binders, educational programs, food fatigue, concordance

  1. Digestible phosphorus levels for barrows from 50 to 80 kg

    Directory of Open Access Journals (Sweden)

    Viviane Maria Oliveira dos Santos Nieto

    2016-05-01

    Full Text Available ABSTRACT This study was carried out to evaluate the levels of digestible phosphorus in diets for barrows with a high potential for lean meat deposition from 50 to 80 kg. Eighty barrows, with an initial weight of 47.93±3.43 kg, were distributed in completely randomized blocks, with each group given five levels of digestible phosphorus (1.86, 2.23, 2.61, 2.99, and 3.36 g kg−1. There were eight replicates, and two animals per experimental unit. Phosphorus levels did not significantly influence feed intake, weight gain, or feed conversion ratio. Daily digestible phosphorus intake increased linearly as levels of phosphorus in the diet were increased. Phosphorus levels did not significantly influence muscle depth, loin eye area, backfat thickness, or the percentage and quantity of lean meat in the carcass. A linear increase was observed for feeding cost as the levels of digestible phosphorus in the diet were increased, and the level of 1.86 g kg−1 cost 29.4% less when compared with the level of 2.61 g kg−1. The dry matter, natural matter, the coefficient of the residue, and volatile solids of the waste were not significantly influenced by phosphorus levels. Conversely, it was possible to observe an increasing linear effect for total solids, total phosphorus, and total nitrogen in the waste of animals receiving diets with increased levels of digestible phosphorus. The level of 1.86 g kg−1, which corresponded to a daily intake of 4.77 g−1 of digestible phosphorus, meets the requirements of barrows weighing 50 to 80 kg.

  2. Process for improving phosphorus-vanadium oxide and phosphorus-vanadium-co-metal oxide catalysts

    International Nuclear Information System (INIS)

    A process is described for the improvement of a vanadium-phosphorus-oxygen catalyst having a phosphorus to vanadium atomic ratio of about 2:1 to about 0.8:1 which catalyst is present on a catalyst bed having a portion therof containing an initial exotherm of reaction. The catalyst is suitable for use in the manufacture of maleic anhydride from a feed gas stream comprising C/sub 4/ hydrocarbons, benzene, or butane which process comprises: applying to the catalyst bed, simultaneously with introduction of the feed gas stream thereon, water and a phosphorus compound in an amount sufficient to initiate (a) deactivation of the portion of the catalyst containing the initial exotherm, and (b) formation of a new exotherm downstream in the catalyst bed from the initial exotherm, and thereafter reducing or discontinuing application of the phosphorus compound at a point in time when the initial exotherm portion of the catalyst bed is still undergoing deactivation, thereby allowing the partially deactivated exotherm portion to reactivate by producing a more isothermal catalyst bed

  3. Phosphorus solubility in an acid forest soil as influenced by form of applied phosphorus and liming

    Energy Technology Data Exchange (ETDEWEB)

    Fransson, Ann-Mari; Bergkvist, Bo; Tyler, Germund [Lund Univ. (Sweden). Dept. of Ecology

    1999-07-01

    Sedimentary phosphorus, superphosphate, and wood-ash, as well as either sedimentary phosphorus. superphosphate or ash combined with lime, were distributed in selected plots in an 80-yr-old Norway spruce forest [Picea abies (L.) Karst]. After 2 yrs, the sedimentary phosphorus had increased the oxalate/oxalic acid-extractable P in the O-horizon, and the superphosphate had increased the oxalate/oxalic acid-extractable P in the E-horizon. At first, the percolation water from the superphosphate treatment showed high P concentrations. It soon returned to control levels, however. The percolation water from the sedimentary phosphorus treatment gradually showed increased phosphate concentrations. The wood-ash increased neither the amount of extractable P nor the P concentration in the percolation water. The oxalate/oxalic acid-extractable P from the sedimentary P treatment was reduced by liming. The P concentration in the percolation water also tended to be reduced. This was perhaps due to formation of Ca phosphates in the vicinity of the lime particles. In addition, if the solubility rate was similar to the uptake rate, it could account for the decreased P concentration.

  4. Application of Wood Char in Processing Oolitic High-phosphorus Hematite for Phosphorus Removal

    Institute of Scientific and Technical Information of China (English)

    Hui-qing TANG; Yan-qi QIN; Teng-fei QI; Zhi-lei DONG; Qing-guo XUE

    2016-01-01

    Phosphorus removal from oolitic high-phosphorus hematite using direct reduction followed by melting sep-aration was investigated.At the direct reduction stage,highly volatile wood char was prepared by carbonizing j uj ube wood at 673 K for 2 h and was used as reducing agent.The results of the direct reduction tests show that at a tem-perature of 1 373 K,a char mixing ratio of 0�8,and a reduction time of 10-25 min,the briquettes reached a metal-lization degree of 80%-84% and a residual carbon content of 0�13-1�98 mass%.Phosphorus remained in the gangue as calcium phosphate after reduction.The results of the melting separation tests show that residual carbon in reduced briquette negatively affects the phosphorus content (w[P])in hot metal.When the reduced briquettes ob-tained under the aforementioned conditions were used for melting separation,hot metal suitable for basic oxygen steelmaking (w[P]<0�4 mass%)could not be obtained from metallic briquettes with a residual carbon content more than 1�0 mass%.In contrast,it could be obtained from metallic briquettes with residual carbon content less than 0�35 mass% by mixing with 2%-4% Na2 CO3 .

  5. Effect of Microwave Treatment Upon Processing Oolitic High Phosphorus Iron Ore for Phosphorus Removal

    Science.gov (United States)

    Tang, Hui-Qing; Liu, Wei-Di; Zhang, Huan-Yu; Guo, Zhan-Cheng

    2014-10-01

    Influence of microwave treatment on the previously proposed phosphorus removal process of oolitic high phosphorus iron ore (gaseous reduction followed by melting separation) has been studied. Microwave treatment was carried out using a high-temperature microwave reactor (Model: MS-WH). Untreated ore fines and microwaved ore fines were then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). Thereafter, experiments on the proposed phosphorus removal process were conducted to examine the effect of microwave treatment. Results show that microwave treatment could change the microstructure of the ore fines and has an intensification effect on its gaseous reduction by reducing gas internal resistance, increasing chemical reaction rate and postponing the occurrence of sintering. Results of gaseous reduction tests using tubular furnace indicate both microwave treatment and high reduction temperature high as 1273 K (1000 °C) are needed to totally break down the dense oolite and metallization rate of the ore fines treated using microwave power of 450 W could reach 90 pct under 1273 K (1000 °C) and for 2 hours. Results of melting separation tests of the reduced ore fines with a metallization rate of 90 pct show that, in addition to the melting conditions in our previous studies, introducing 3 pct Na2CO3 to the highly reduced ore fines is necessary, and metal recovery rate and phosphorus content of metal could reach 83 pct and 0.31 mass pct, respectively.

  6. Phosphorus availability for plant uptake in a phosphorus-enriched noncalcareous sandy soil

    NARCIS (Netherlands)

    Koopmans, G.F.; Chardon, W.J.; Ehlert, P.A.I.; Dolfing, J.; Suurs, R.A.A.; Oenema, O.; Riemsdijk, van W.H.

    2004-01-01

    Mining soil phosphorus (i.e., harvesting P taken up from the soil by a crop grown without external P addition) has been proposed as a possible management strategy for P-enriched soils to decrease the risk of P leaching. We performed a pot experiment in a greenhouse where grass was cropped on a P-enr

  7. COMPARISON OF SOIL PHOSPHORUS TEST METHODS

    Directory of Open Access Journals (Sweden)

    Brigita Popović

    2010-06-01

    Full Text Available Soil-P test is obligate chemical analysis for soil productivity estimation and most frequent used method in Croatia is AL method (soil extraction by ammoniumlactate solution at pH 3.75. Howewer, in some soils AL method (especially calcareous could be inaccurate for phosphorus fertilizer recommendations and crop response could be inadequate. Hence, the aim of this research was to compare 6 different P-tests: Olsen, Morgan, Bray1, Bray 2, CAL and DL. Each of these methods had a different pH of extraction solutios: Olsen (pH 8.5, Morgan (4,8, Bray 1 and Bray 2 (2.6, CAL (4.1 DL (3.7. Aiming to compare these 7 soil tests, 360 soil samples were collected from the continental part od Croatia. The soil pH, organic matter, AL-P2O5 and % CaCO3 were analyzed. All samples were grouped according to soil pH in two groups (pHKCl 6 179 samples. Phosphorus content on the average decreased: Bray 1 > DL > AL > CAL > Bray 2> Olsen > Morgan. Significant corellations were estimeted between AL and Olsen P test (r= 0.88, AL and Bray 1 P test (r=0.68, Olsen and Bray 1 P test (r= 0,75 and CAL and DL P tests (r=0.45. In the analysed samples total phospohrus content was recorded in all samples and portion of organic phosphorus in total phosporus in soil ranged from 0.54 to 78.29 %. The developed models are very simple and useful because they can predict soil phosphurus using only one soil test data. The models were validated and showed that all recorded corelations in this study were precise and approved the aforementioned models accuracy.

  8. Elastic properties of suspended black phosphorus nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jia-Ying; Li, Yang; Zhen, Liang; Xu, Cheng-Yan, E-mail: cy-xu@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); MOE Key Laboratory of Micro-systems and Micro-structures Manufacturing, Harbin Institute of Technology, Harbin 150080 (China); Zhan, Zhao-Yao [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714 (China); Li, Tie [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2016-01-04

    The mechanical properties of black phosphorus (BP) nanosheets suspended over circular holes were measured by an atomic force microscope nanoindentation method. The continuum mechanic model was introduced to calculate the elastic modulus and pretension of BP nanosheets with thicknesses ranging from 14.3 to 34 nm. Elastic modulus of BP nanosheets declines with thickness, and the maximum value is 276 ± 32.4 GPa. Besides, the effective strain of BP ranges from 8 to 17% with a breaking strength of 25 GPa. Our results show that BP nanosheets serve as a promising candidate for flexible electronic applications.

  9. Phosphorus leaching in relation to soil type and soil phosphorus content.

    Science.gov (United States)

    Djodjic, Faruk; Börling, Katarina; Bergström, Lars

    2004-01-01

    Phosphorus losses from arable soils contribute to eutrophication of freshwater systems. In addition to losses through surface runoff, leaching has lately gained increased attention as an important P transport pathway. Increased P levels in arable soils have highlighted the necessity of establishing a relationship between actual P leaching and soil P levels. In this study, we measured leaching of total phosphorus (TP) and dissolved reactive phosphorus (DRP) during three years in undisturbed soil columns of five soils. The soils were collected at sites, established between 1957 and 1966, included in a long-term Swedish fertility experiment with four P fertilization levels at each site. Total P losses varied between 0.03 and 1.09 kg ha(-1) yr(-1), but no general correlation could be found between P concentrations and soil test P (Olsen P and phosphorus content in ammonium lactate extract [P-AL]) or P sorption indices (single-point phosphorus sorption index [PSI] and P sorption saturation) of the topsoil. Instead, water transport mechanism through the soil and subsoil properties seemed to be more important for P leaching than soil test P value in the topsoil. In one soil, where preferential flow was the dominant water transport pathway, water and P bypassed the high sorption capacity of the subsoil, resulting in high losses. On the other hand, P leaching from some soils was low in spite of high P applications due to high P sorption capacity in the subsoil. Therefore, site-specific factors may serve as indicators for P leaching losses, but a single, general indicator for all soil types was not found in this study. PMID:15074820

  10. Chemical and biological properties of phosphorus-fertilized soil under legume and grass cover (Cerrado region, Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Fernando Pereira Souza

    2013-12-01

    Full Text Available The use of cover crops has been suggested as an effective method to maintain and/or increase the organic matter content, while maintaining and/or enhancing the soil physical, chemical and biological properties. The fertility of Cerrado soils is low and, consequently, phosphorus levels as well. Phosphorus is required at every metabolic stage of the plant, as it plays a role in the processes of protein and energy synthesis and influences the photosynthetic process. This study evaluated the influence of cover crops and phosphorus rates on soil chemical and biological properties after two consecutive years of common bean. The study analyzed an Oxisol in Selvíria (Mato Grosso do Sul, Brazil, in a randomized block, split plot design, in a total of 24 treatments with three replications. The plot treatments consisted of cover crops (millet, pigeon pea, crotalaria, velvet bean, millet + pigeon pea, millet + crotalaria, and millet + velvet bean and one plot was left fallow. The subplots were represented by phosphorus rates applied as monoammonium phosphate (0, 60 and 90 kg ha-1 P2O5. In August 2011, the soil chemical properties were evaluated (pH, organic matter, phosphorus, potential acidity, cation exchange capacity, and base saturation as well as biological variables (carbon of released CO2, microbial carbon, metabolic quotient and microbial quotient. After two years of cover crops in rotation with common bean, the cover crop biomass had not altered the soil chemical properties and barely influenced the microbial activity. The biomass production of millet and crotalaria (monoculture or intercropped was highest. The biological variables were sensitive and responded to increasing phosphorus rates with increases in microbial carbon and reduction of the metabolic quotient.

  11. Potential impact of dietary choices on phosphorus recycling and global phosphorus footprints: the case of the average Australian city

    Directory of Open Access Journals (Sweden)

    Genevieve Metson

    2016-08-01

    Full Text Available Changes in human diets, population increase, changes in farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are however threatened by such increased phosphorus consumption because the world’s main source, phosphate rock, is an increasingly scarce resource. At the same time losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are two-fold: First, dietary choices affects a person or region’s ‘phosphorus footprint’ – the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta, and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g. potential for recycling, dietary changes may be undervalued as a solution towards phosphorus sustainability. In an average Australian city for example, a vegetable-based diet could marginally increase phosphorus in human excreta (8% increase. However such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident’s annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management.

  12. Anthropogenic phosphorus flow analysis of Hefei City, China

    International Nuclear Information System (INIS)

    The substance flow analysis (SFA) method was employed to examine phosphorus flow and its connection to water pollution in the city of Hefei, China, in 2008. As human activity is the driving force of phosphorus flux from the environment to the economy, the study provides a conceptual framework for analyzing an anthropogenic phosphorus cycle that includes four stages: extraction, fabrication and manufacturing, use, and waste management. Estimates of phosphorus flow were based on existing data as well as field research, expert advice, local accounting systems, and literature. The total phosphorus input into Hefei in 2008 reached 7810 tons, mainly as phosphate ore, chemical fertilizer, pesticides, crops and animal products. Approximately 33% of the total phosphorus input left the area, and nearly 20% of that amount was discharged as waste to surface water. Effluent containing excessive fertilizer from farming operations plays an important role in phosphorus overloads onto surface water; the other major emission source is sewage discharge. We also provide suggestions for reducing phosphorus emissions, for example reducing fertilizer use, recycling farming residues, and changing human consumption patterns.

  13. The total phosphorus budget of a peat-covered catchment

    Science.gov (United States)

    Worrall, Fred; Moody, Catherine S.; Clay, Gareth D.; Burt, Tim P.; Rose, Rob

    2016-07-01

    Although many studies have considered the carbon or greenhouse gas budgets of peat ecosystems, only a few have considered the nutrient budget of peat soils, and this, in turn, has limited the ability of studies to consider the impact of changes in climate and atmospheric deposition on the phosphorus budget of a peat soil. This study considered the total phosphorus (P) budget of an upland peat-covered catchment over the period 1993 to 2012. The study has shown (i) total atmospheric deposition of phosphorus varied from 62 to 175 kg P/km2/yr; (ii) the carbon:phosphorus ratio of the peat profile declines significantly from values in the litter layer (C:P = 1326) to approximately constant at 30 cm depth (C:P = 4240); (iii) the total fluvial flux of phosphorus varied from 49 to 111 kg P/km2/yr, of which between 45 and 77% was dissolved P; and (iv) the total phosphorus sink varied from -5.6 to +71.7 kg P/km2/yr with a median of +29.4 kg P/km2/yr, which is within the range of the estimated long-term accumulation rate of phosphorus in the peat profile of between 3 and 32 kg P/km2/yr. The phosphorus budget of the peat ecosystem relies on rapid recycling near the soil surface, and this means that any vegetation management may critically deprive the ecosystem of this nutrient.

  14. Environmental Benefits and Burdens of Phosphorus Recovery from Municipal Wastewater.

    Science.gov (United States)

    Bradford-Hartke, Zenah; Lane, Joe; Lant, Paul; Leslie, Gregory

    2015-07-21

    The environmental benefits and burdens of phosphorus recovery in four centralized and two decentralized municipal wastewater systems were compared using life cycle assessment (LCA). In centralized systems, phosphorus recovered as struvite from the solids dewatering liquid resulted in an environmental benefit except for the terrestrial ecotoxicity and freshwater eutrophication impact categories, with power and chemical use offset by operational savings and avoided fertilizer production. Chemical-based phosphorus recovery, however, generally required more resources than were offset by avoided fertilizers, resulting in a net environmental burden. In decentralized systems, phosphorus recovery via urine source separation reduced the global warming and ozone depletion potentials but increased terrestrial ecotoxicity and salinization potentials due to application of untreated urine to land. Overall, mineral depletion and eutrophication are well-documented arguments for phosphorus recovery; however, phosphorus recovery does not necessarily present a net environmental benefit. While avoided fertilizer production does reduce potential impacts, phosphorus recovery does not necessarily offset the resources consumed in the process. LCA results indicate that selection of an appropriate phosphorus recovery method should consider both local conditions and other environmental impacts, including global warming, ozone depletion, toxicity, and salinization, in addition to eutrophication and mineral depletion impacts. PMID:26121005

  15. Ups and Downs of the Yellow Phosphorus Market in 2007

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 1 Surplus capacity The rapid growth of the economy in China promoted drastic development of the yellow phosphorus sector from 1985 to 2004. The capacity of yellow phosphorus expanded rapidly from 100 000 t/a in 1985 to 1.2 million t/a in 2004 with an average annual growth of around 14.0%.

  16. Removal of Phosphorus from Silicon Melts by Vacuum Refining

    OpenAIRE

    Xakalashe, Buhle Sinaye

    2011-01-01

    Induction vacuum refining testwork has been carried out for the removal of phosphorus from silicon melts. This work is of interest for the production of solar-grade silicon, since phosphorus is hard to remove from silicon and an important impurity in solar cells.

  17. Biological Phosphorus Removal in a Moving Bed Biofilm Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Helness, Herman

    2007-09-15

    The scope of this study was to investigate use of the moving bed biofilm reactor (MBBR) process for biological phosphorus removal. The goal has been to describe the operating conditions required for biological phosphorus and nitrogen removal in a MBBR operated as a sequencing batch reactor (SBR), and determine dimensioning criteria for such a process

  18. Phosphorus Removal By Silage Corn In Southern Idaho

    Science.gov (United States)

    Corn silage is the predominant crop in Idaho used for recovering phosphorus (P) that has accumulated in soils from dairy manure applications. However, little is known about how much phosphorus and other nutrients are being recovered under Idaho conditions. The objective of the study is to estimate p...

  19. Phosphorus recovery from pig manure solids prior to land application

    Science.gov (United States)

    Land disposal of pig manure is an environmental concern due to an imbalance of the nitrogen to phosphorus (N:P) ratio for crop production, leading to excess phosphorus (P) in soils and potential risks of water pollution. A process called “quick wash” was investigated for its feasibility to extract ...

  20. The release of dissolved phosphorus from lake sediments.

    NARCIS (Netherlands)

    Boers, P.C.M.

    1991-01-01

    Chapter 1. Introduction: Eutrophication is one of the world's major water quality problems. Attempts to alleviate eutrophication of lakes have involved the control of phosphorus loadings. In such cases, an internal loading of phosphorus from the sediments may retard an improvement o

  1. Phosphorus isothermal adsorption characteristics of mulch of bioretention

    Directory of Open Access Journals (Sweden)

    Mei Ying

    2012-01-01

    Full Text Available This study aims to identify mulch of bioretention which has high phosphorus sorption capacity. The phosphorus adsorption characteristics of five types of mulch of bioretention are studied by three isothermal adsorption experiments. Results show that the Langmuir eqution is suitable for describing absorption characteristics of five types of mulch. The positive values of Gibbs free energy for phosphorus indicate that the phosphorus biosorption by five mulches is a non-spontaneous process, and the values of mean sorption free energy of mulch are less than 8 kJ/mol, which proves that the adsorption process can be dominated by physical forces. The vermiculite is the better mulch of bioretention based on high phosphorus removal capacity.

  2. Soil phosphorus and the ecology of lowland tropical forests

    Science.gov (United States)

    Turner, Ben

    2016-04-01

    In this presentation I will explore the extent to which phosphorus influences the productivity, diversity, and distribution of plant species in tropical forests. I will highlight the range of soils that occur in tropical forests and will argue that pedogenesis and associated phosphorus depletion is a primary driver of forest diversity over long timescales. I will draw on data from a regional-scale network of forest dynamics plots in Panama to show that tree species distributions are determined predominantly as a function of dry season intensity and soil phosphorus availability, and will suggest potential mechanistic explanations for this pattern in relation to phosphorus acquisition. Finally, I will present observational and experimental evidence from Panama to show how phosphorus, nitrogen, and potassium, limit plant productivity and microbial communities on strongly-weathered soils in the lowland tropics.

  3. Influence of phosphorus on point defects in an austenitic alloy

    International Nuclear Information System (INIS)

    The influence of phosphorus on points defects clusters has been studied in an austenitic alloy (Fe/19% at. Cr/13% at. Ni). Clusters are observed by transmission electron microscopy. After quenching and annealing, five types of clusters produced by vacancies or phosphorus-vacancies complexes are observed whose presence depends on cooling-speed. Vacancy concentration (with 3.6 10-3 at. P) in clusters is about 10-5 and apparent vacancy migration is 2± 0.1 eV. These observations suggest the formation of metastable small clusters during cooling which dissociate during annealing and migrate to create the observed clusters. With phosphorus, the unfrequent formation of vacancy loops has been observed during electron irradiation. Ions irradiations show that phosphorus does not favour nucleation of interstitial loops but slowers their growth. It reduces swelling by decreasing voids diameter. Phosphorus forms vacancy complexes whose role is to increase the recombination rate and to slow vacancy migration

  4. Denuded Zone Formation in Germanium Codoped Heavily Phosphorus-Doped Czochralski Silicon

    Institute of Scientific and Technical Information of China (English)

    LIN Li-Xia; CHEN Jia-He; WU Peng; ZENG Yu-Heng; MA Xiang-Yang; YANG De-Ren

    2011-01-01

    The formation of a denuded zone(DZ) by conventional furnace annealing(CFA) and rapid thermal annealing (RTA) based denudation processing is investigated and the gettering of copper(Cu) atoms in germanium co-doped heavily phosphorus-doped Czochralski(GHPCZ)silicon wafers is evaluated. It is suggested that both a good quality defect-free DZ with a suitable width in the sub-surface area and a high density bulk micro-defect(BMD)region could be formed in heavily phosphorus-doped Czochralski(HPCZ)silicon and GHPCZ silicon wafers.This is ascribed to the formation of phosphorus-vacancy(P-V) related complexes and germanium-vacancy(GeV) related complexes. Compared with HPCZ silicon, the DZ width is wider in the GHPCZ silicon sample with CFA-based denudation processing but narrower in the one with two-step RTA pretreatments. These phenomena are ascribed to the enhancing effect of germanium on oxygen out-diffusion movement and oxygen precipitate nucleation, respectively. Furthermore, fairly clean DZs near the surface remain in both the HPCZ and GHPCZ silicon wafers after Cu in-diffusion, except for the HPCZ silicon wafer which underwent denudation processing with a CFA pretreatment, suggesting that germanium doping could improve the gettering of Cu contamination.

  5. Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean

    Science.gov (United States)

    Ezzat, Leïla; Maguer, Jean-François; Grover, Renaud; Ferrier-Pagès, Christine

    2016-01-01

    During the 20th century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health. PMID:27531136

  6. Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean.

    Science.gov (United States)

    Ezzat, Leïla; Maguer, Jean-François; Grover, Renaud; Ferrier-Pagès, Christine

    2016-08-17

    During the 20(th) century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health.

  7. Improving phosphorus availability from Patos phosphate rock for Eucalyptus: a study with 32P radiotracer

    International Nuclear Information System (INIS)

    Eucalyptus plantation in Brazil is generally set on low fertility soils, therefore phosphorus (P) fertilization is mandatory and increases the cost of plantation operation. Using species that more efficiently uptake phosphorus from less soluble sources is an interesting option. However, little is known about eucalyptus regarding its ability of using less soluble forms of phosphorus. The use of P by eucalyptus (E. urophylla, E. grandis, and E. urophylla E. grandis) was studied in greenhouse using a loamy-textured, hipodystrophic Typic Haplustox from the Cerrado region, and 32P isotopic method. The P sources tested were triple superphosphate (TSP), phosphate rock (PR) and the triple superphosphate mixed with PR (TSP+PR). The effectiveness of P sources in terms of increasing dry matter yield was TSP = (TSP + PR) > PR, and the P uptake followed the order (TSP + PR) > TSP > PR for both species plus the hybrid. The increase in P uptake from PR due to TSP influence was 217.3% for E. urophylla, 235.7% for E. grandis, and 28.7% for E. urophylla E. grandis, indicating an enhancement effect of TSP on the effectiveness of PR. The hybrid E. urophylla E. grandis was the most efficient genotype on P soil use and E. grandis most exigent in P fertilizer. (author)

  8. Atmospheric pressure microwave sample preparation procedure for the combined analysis of total phosphorus and kjeldahl nitrogen.

    Science.gov (United States)

    Collins, L W; Chalk, S J; Kingston, H M

    1996-08-01

    An atmospheric pressure microwave digestion method has been developed for the combined analysis of total phosphorus and Kjeldahl nitrogen in complex matrices. In comparison to the digestion steps in EPA Methods 365.4 (total phosphorus) and 351.x (Kjeldahl nitrogen), this method requires less time, eliminates the need for a catalyst, and reduces the toxicity of the waste significantly. It employs a microwave-assisted digestion step, using refluxing borosilicate glass vessels at atmospheric pressure. Traditionally, this method has a time-consuming sample preparation step and generates toxic waste through the use of heavy metal catalysts. These advantages are gained by the combination of a high boiling point acid (sulfuric acid) and the application of focused microwave irradiation, which enhances the digestion process by direct energy coupling. NIST standard reference materials 1572 (citrus leaves), 1577a (bovine liver), and 1566 (oyster tissue) and tryptophan were analyzed to validate the method. Phosphorus concentrations were determined by the colorimetric ascorbic acid method outlined in EPA Method 365.3. Kjeldahl nitrogen concentrations were determined using EPA Method 351.1. The results of the analyses showed good precision and are in excellent agreement with the NIST published values for both elements.

  9. Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean.

    Science.gov (United States)

    Ezzat, Leïla; Maguer, Jean-François; Grover, Renaud; Ferrier-Pagès, Christine

    2016-01-01

    During the 20(th) century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health. PMID:27531136

  10. Theoretical Study on Adsorption of Methanol on Zeolite and Phosphorus Modified Zeolite

    Institute of Scientific and Technical Information of China (English)

    Lü Renqing; Li Ting; Gu Jun; Liu Chenguang

    2004-01-01

    Methanol adsorption in zeolite and phosphorus modified zeolite has been investigated within the cluster model framework of quantum chemical calculation. Full optimization and frequency analysis of all cluster model have been carried out using Gaussian 94 soft package with Hartree-Fock method and B3LYP, B3P86 hybrid methods of density functional theory at 3-2 1 G, 6-31G basis set level for hydrogen atoms and 6-31G+(d) basis set level for the other atoms performed on small cluster model for CH3OH, H3Al(OH)SiH2(H2PO4), H3Al(OH)SiH2(H3SiO4), H3Al(OH-CH3OH)SiH2(H2PO4) and H3Al(OHCH3OH)SiH2(H3SiO4). The results show that phosphorus grafting in the zeolite framework has modified the chemical environment in the vicinity of the zeolite bridging hydroxyl. Phosphorus modification can enhance the acid strength of zeolite bridging hydroxyl, which was suggested by the lengthening of zeolite bridging hydroxyl O-H bond and the increasing methanol adsorption energy. This may be favorable to the initial CH3OCH3 formation in the methanol to gasoline (MTG) process.

  11. Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean

    Science.gov (United States)

    Ezzat, Leïla; Maguer, Jean-François; Grover, Renaud; Ferrier-Pagès, Christine

    2016-08-01

    During the 20th century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health.

  12. Seasonal Phosphorus Dynamics in Turfgrass of Different Purposes

    Directory of Open Access Journals (Sweden)

    Mirjana Herak Ćustić

    2016-05-01

    Full Text Available Phosphorus (P is a component of phospholipids, nucleic acids and molecules that store energy. It increases yield and water and nutrients use efficiency. Phosphorus turfgrass content is essential for root development, and, indirectly, nutrient uptake. The aim of this research was to determine soil and turfgrass blade phosphorus dynamics on two recreational (parks Bundek and Jarun and two sports (Hippodrome and SP Mladost turfgrasses in the city of Zagreb and determine adequate fertilization. Soil and plant material sampling was performed three times during the growing season 2012 in each of the four investigated locations. The results showed that, generally, soil phosphorus content was low or even turfgrass blade phosphorus content was on the lower end of optimal supply range. Soil phosphorus values ranged from 1.78 to 6.78 mg P2O5 100 g-1, while turfgrass blade phosphorus content ranged from 0.15 to 0.45 % P. Sampling time does not affect turfgrass blade phosphorus content. Due to the particularly low soil and turfgrass blade phosphorus status, special attention when designing the fertilization program should be given to phosphorus application with at least 10 g of P2O5 m-2 in the early spring, and, if necessary, with 1 g of P2O5 m-2 during the growing season. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";}

  13. Soil Phosphorus Gains and Losses with Afforestation: A Meta-analysis

    Science.gov (United States)

    McMahon, D.; Deng, Q.; Xiang, Y.; Yu, C. L.; Hui, D.; Jackson, R. B.

    2015-12-01

    Afforestation, the planting of trees on previously non-forested land, is commonly practiced around the world to provide wood, reduce erosion, and restore degraded agricultural land. Although afforestation has the potential to meet these objectives while increasing carbon uptake, its net impact on the soil depends on environmental conditions and land-use history. Availability of vital plant nutrients, such as phosphorus (P), may be altered by afforestation, but prior work has largely focused on soil carbon, and changes in soil P had not been quantitatively reviewed. We conducted a literature meta-analysis of changes in total and plant-available soil P with afforestation, compiling 49 studies representing 186 independent forest stands on five continents. Over the full dataset, mean concentration of plant-available phosphorus (mg kg-1 soil) increased by 22.7% with afforestation (bootstrapped 95% confidence interval = [15.1%, 30.7%]), while mean concentration of total phosphorus decreased by 13.5% (95% CI = [-18.4%, -8.6%]). These data reflect trends in upper mineral soil horizons, with sampling depths clustered around 20 cm and few studies reporting data below 50 cm. Differences in prior land use partially explain the substantial variation in effect size, with larger increases in available P and smaller decreases in total P when trees were planted on degraded soils. Trends in both available and total P were also enhanced with increasing time since afforestation, suggesting that changes in soil P concentrations are driven by cumulative processes rather than site preparation and planting. Our meta-analysis suggests that 1. afforestation can transform phosphorus into more plant-accessible forms, while potentially depleting total soil stocks of P, and 2. land-use history, more than climate or species planted, determines the effects of afforestation on soils' ability to meet the nutrient needs of vegetation.

  14. Toughening by the addition of phosphorus to a high-strength steel with ultrafine elongated grain structure

    Science.gov (United States)

    Jafari, Meysam; Kimura, Yuuji; Tsuzaki, Kaneaki

    2013-02-01

    Phosphorus-doped high-strength steels are typically brittle at room temperature. In contrast to the non-hardening embrittlement of body-centred cubic (bcc) steels which decreases toughness without increasing strength, we observed an increase in toughness of about 20% by adding a large amount (0.053 wt%) of phosphorus (P) to a high-strength bcc steel with an ultrafine elongated ferrite grain structure processed by warm calibre rolling at 500 °C which produced a 91% reduction in area. The enhanced toughness is attributed to P segregation, which causes grain boundaries to become feasible crack propagation paths, thereby enhancing delamination toughening. The 0.053% P steel showed a microstructure and tensile properties similar to those of 0.001% P steel (reference steel).

  15. Reduction of phosphorus diffusion in germanium by fluorine implantation

    Science.gov (United States)

    El Mubarek, H. A. W.

    2013-12-01

    The control of phosphorus (P) diffusion in germanium (Ge) is essential for the realisation of ultrashallow n-type junctions in Ge. This work reports a detailed study of the effect of fluorine (F) co-implantation on P diffusion in Ge. P and F profiles were characterized by secondary ion mass spectroscopy. The ion implantation damage was investigated using cross sectional transmission electron microscopy. It is shown that F co-implantation reduces the implanted P profile width and reduces both intrinsic and extrinsic P diffusion in Ge. A defect mediated mechanism for the strong influence of F co-implantation on P diffusion in Ge is proposed and invokes the formation of FnVm clusters in the F-amorphized Ge layer. A fraction of these FnVm clusters decorate the interstitial type end-of-range defects in the re-grown Ge layer and the rest react during re-growth with interstitial germanium atoms diffusing back from the amorphous crystalline interface. The Ge vacancies are then annihilated and mobile interstitial F is released and out diffuses from the surface. This results in a re-grown Ge layer which has a low vacancy concentration and in which the P diffusion rate is reduced. These results open the way to the realization of enhanced Ge n-type devices.

  16. Reduction of phosphorus diffusion in germanium by fluorine implantation

    Energy Technology Data Exchange (ETDEWEB)

    El Mubarek, H. A. W. [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom)

    2013-12-14

    The control of phosphorus (P) diffusion in germanium (Ge) is essential for the realisation of ultrashallow n-type junctions in Ge. This work reports a detailed study of the effect of fluorine (F) co-implantation on P diffusion in Ge. P and F profiles were characterized by secondary ion mass spectroscopy. The ion implantation damage was investigated using cross sectional transmission electron microscopy. It is shown that F co-implantation reduces the implanted P profile width and reduces both intrinsic and extrinsic P diffusion in Ge. A defect mediated mechanism for the strong influence of F co-implantation on P diffusion in Ge is proposed and invokes the formation of F{sub n}V{sub m} clusters in the F-amorphized Ge layer. A fraction of these F{sub n}V{sub m} clusters decorate the interstitial type end-of-range defects in the re-grown Ge layer and the rest react during re-growth with interstitial germanium atoms diffusing back from the amorphous crystalline interface. The Ge vacancies are then annihilated and mobile interstitial F is released and out diffuses from the surface. This results in a re-grown Ge layer which has a low vacancy concentration and in which the P diffusion rate is reduced. These results open the way to the realization of enhanced Ge n-type devices.

  17. Phosphorus starvation induces membrane remodeling and recycling in Emiliania huxleyi.

    Science.gov (United States)

    Shemi, Adva; Schatz, Daniella; Fredricks, Helen F; Van Mooy, Benjamin A S; Porat, Ziv; Vardi, Assaf

    2016-08-01

    Nutrient availability is an important factor controlling phytoplankton productivity. Phytoplankton contribute c. 50% of the global photosynthesis and possess efficient acclimation mechanisms to cope with nutrient stress. We investigate the cellular response of the bloom-forming coccolithophore Emiliania huxleyi to phosphorus (P) scarcity, which is often a limiting factor in marine ecosystems. We combined mass spectrometry, fluorescence microscopy, transmission electron microscopy (TEM) and gene expression analyses in order to assess diverse cellular features in cells exposed to P limitation and recovery. Early starvation-induced substitution of phospholipids in the cells' membranes with galacto- and betaine lipids. Lipid remodeling was rapid and reversible upon P resupply. The PI3K inhibitor wortmannin reduced phospholipid substitution, suggesting a possible involvement of PI3K- signaling in this process. In addition, P limitation enhanced the formation and acidification of membrane vesicles in the cytoplasm. Intracellular vesicles may facilitate the recycling of cytoplasmic content, which is engulfed in the vesicles and delivered to the main vacuole. Long-term starvation was characterized by a profound increase in cell size and morphological alterations in cellular ultrastructure. This study provides cellular and molecular basis for future ecophysiological assessment of natural E. huxleyi populations in oligotrophic regions. PMID:27111716

  18. Phosphorus doping of Si nanocrystals: Interface defects and charge compensation

    Science.gov (United States)

    Stegner, A. R.; Pereira, R. N.; Klein, K.; Wiggers, H.; Brandt, M. S.; Stutzmann, M.

    2007-12-01

    Using electron paramagnetic resonance (EPR), Fourier-transform infrared absorption (FTIR) and temperature programmed desorption (TPD), we have investigated the doping of silicon nanocrystals (Si-ncs) and the interaction between intrinsic defects and dopants. Si-ncs were produced in a low-pressure microwave plasma reactor using silane as precursor gas. Phosphorus doping was achieved by addition of phosphine to the precursor gas. The low temperature EPR spectra of all P-doped samples display a line at g=1.998, which is the fingerprint of substitutional P in crystalline silicon for [P]>1018 cm-3. In addition, the characteristic hyperfine signature of P in Si is also observed for samples with nominal P doping levels below 1019 cm-3. Two more features are observed in our EPR spectra: a broad band located at g=2.0056, due to isotropic Si dangling bonds (Si-dbs), and an axially symmetric powder pattern (g⊥=2.0087,g∥=2.0020) arising from Si-dbs at the interface between the crystalline Si core and a native oxide shell. The formation of this oxide layer and the presence of different H-termination configurations are revealed by FTIR spectroscopy. The density of Si-dbs is reduced in P-doped samples, indicating a sizable compensation of the doping by Si-dbs. This compensation effect was verified by H desorption, which enhances the density of Si-dbs, in combination with TPD and FTIR.

  19. Gate-Tuned Thermoelectric Power in Black Phosphorus.

    Science.gov (United States)

    Saito, Yu; Iizuka, Takahiko; Koretsune, Takashi; Arita, Ryotaro; Shimizu, Sunao; Iwasa, Yoshihiro

    2016-08-10

    The electric field effect is a useful means of elucidating intrinsic material properties as well as for designing functional devices. The electric-double-layer transistor (EDLT) enables the control of carrier density in a wide range, which is recently proved to be an effective tool for the investigation of thermoelectric properties. Here, we report the gate-tuning of thermoelectric power in a black phosphorus (BP) single crystal flake with the thickness of 40 nm. Using an EDLT configuration, we successfully control the thermoelectric power (S) and find that the S of ion-gated BP reached +510 μV/K at 210 K in the hole depleted state, which is much higher than the reported bulk single crystal value of +340 μV/K at 300 K. We compared this experimental data with the first-principles-based calculation and found that this enhancement is qualitatively explained by the effective thinning of the conduction channel of the BP flake and nonuniformity of the channel owing to the gate operation in a depletion mode. Our results provide new opportunities for further engineering BP as a thermoelectric material in nanoscale.

  20. Plant adaptations to severely phosphorus-impoverished soils.

    Science.gov (United States)

    Lambers, Hans; Martinoia, Enrico; Renton, Michael

    2015-06-01

    Mycorrhizas play a pivotal role in phosphorus (P) acquisition of plant roots, by enhancing the soil volume that can be explored. Non-mycorrhizal plant species typically occur either in relatively fertile soil or on soil with a very low P availability, where there is insufficient P in the soil solution for mycorrhizal hyphae to be effective. Soils with a very low P availability are either old and severely weathered or relatively young with high concentrations of oxides and hydroxides of aluminium and iron that sorb P. In such soils, cluster roots and other specialised roots that release P-mobilising carboxylates are more effective than mycorrhizas. Cluster roots are ephemeral structures that release carboxylates in an exudative burst. The carboxylates mobilise sparingly-available sources of soil P. The relative investment of biomass in cluster roots and the amount of carboxylates that are released during the exudative burst differ between species on severely weathered soils with a low total P concentration and species on young soils with high total P concentrations but low P availability. Taking a modelling approach, we explore how the optimal cluster-root strategy depends on soil characteristics, thus offering insights for plant breeders interested in developing crop plants with optimal cluster-root strategies. PMID:25912783

  1. Simultaneous nitrogen and phosphorus removal under low dissolved oxygen conditions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A full-scale test was operated by using low dissolved oxygen activated sludge process to enhance biological nitrogen and phosphorus removal. When the influent concentrations of CODCr, TN and TP varied in a range of 352.9 mg/L-1338.2 mg/L, 34.4 mg/L-96.3 mg/L, and 2.21 mg/L-24.0 mg/L, the average removal efficiencies were 94.9%, 86.7% and 93.0%, respectively. During the test period of two months, effluent meas of CODCr, BOD5, NH3-N, TN and TP were below 50 mg/L, 25 mg/L, 10 mg/L and 1.0 mg/L, respectively. The low dissolved oxygen activated sludge process has a simple flow sheet, fewer facilities and high N and P removal efficiency. It is very convenient to retrofit the conventional activated sludge process with the above process.

  2. Device performance simulations of multilayer black phosphorus tunneling transistors

    Science.gov (United States)

    Liu, Fei; Shi, Qing; Wang, Jian; Guo, Hong

    2015-11-01

    We report a theoretical investigation of ballistic transport in multilayer black phosphorus (BP) tunneling transistors (TFETs) with HfO2 as the gate oxide. First-principles calculations show that monolayer BP can be preserved well on HfO2 (111) surface. For a better device performance, the optimum layer and transport direction at different channel lengths are investigated. It is shown that BP TFETs have larger drain current in the armchair direction (AD) than in the zigzag direction, and the current difference can be several orders of magnitude. On-state current can be enhanced in the BP TFETs using thicker BP film, while the minimal leakage current is increased at the same time. To reduce the leakage current and subthreshold swing in the multilayer BP TFETs, lower source/drain doping concentration and smaller drain voltage should be applied. Compared to monolayer MoS2, MoSe2, and MoTe2 TFETs monolayer BP TFETs in AD can reach larger on-state current at the same Ion/Ioff ratio.

  3. Localization effects in the tunnel barriers of phosphorus-doped silicon quantum dots

    Directory of Open Access Journals (Sweden)

    T. Ferrus

    2012-06-01

    Full Text Available We have observed a negative differential conductance with singular gate and source-drain bias dependences in a phosphorus-doped silicon quantum dot. Its origin is discussed within the framework of weak localization. By measuring the current-voltage characteristics at different temperatures as well as simulating the tunneling rates dependences on energy, we demonstrate that the presence of shallow energy defects together with an enhancement of localization satisfactory explain our observations. Effects observed in magnetic fields are also discussed.

  4. Effect of different carbon sources on the biological phosphorus removal by a sequencing batch reactor using pressurized pure oxygen

    OpenAIRE

    Wei, Jie; Imai, Tsuyoshi; Higuchi, Takaya; Arfarita, Novi; YAMAMOTO, Koichi; Sekine, Masahiko; Kanno, Ariyo

    2014-01-01

    The effect of different carbon source on the efficiency of enhanced biological phosphorus removal (EBPR) from synthetic wastewater with acetate and two ratios of acetate/starch as a carbon source was investigated. Three pressurized pure oxygen sequencing batch reactor (POSBR) experiments were operated. The reactors (POSBR1, POSBR2 and POSBR3) were developed and studied at different carbon source ratios of 100% acetate, 75% acetate plus 25% starch and 50% acetate plus 50% starch, respectively....

  5. Manipulation of oil synthesis in Nannochloropsis strain NIES-2145 with a phosphorus starvation–inducible promoter from Chlamydomonas reinhardtii

    OpenAIRE

    Iwai, Masako; Hori, Koichi; Sasaki-Sekimoto, Yuko; Shimojima, Mie; Ohta, Hiroyuki

    2015-01-01

    Microalgae accumulate triacylglycerols (TAGs) under conditions of nutrient stress. Phosphorus (P) starvation induces the accumulation of TAGs, and the cells under P starvation maintain growth through photosynthesis. We recently reported that P starvation–dependent overexpression of type-2 diacylglycerol acyl-CoA acyltransferase (CrDGTT4) from Chlamydomonas reinhardtii using a sulfoquinovosyldiacylglycerol synthase 2 (SQD2) promoter, which has increased activity during P starvation, enhances T...

  6. Influence of soil phosphorus and manure on phosphorus leaching in Swedish topsoils

    OpenAIRE

    Svanbäck, Annika; Ulen, Barbro; Etana, Ararso; Bergström, Lars; Kleinman, Peter J.A.; Mattsson, Lennart

    2013-01-01

    In Sweden, subsurface transport of phosphorus (P) from agricultural soils represents the primary pathway of concern for surface water quality. However, there are mixed findings linking P in leachate with soil P and limited understanding of the interactive effects of applied P sources and soil test P on P leaching potential. Identifying soils that are susceptible to P leaching when manure is applied is critical to management strategies that reduce P loadings to water bodies. Intact soil column...

  7. Preliminary analysis of phosphorus flow in Hue Citadel.

    Science.gov (United States)

    Anh, T N Q; Harada, H; Fujii, S; Anh, P N; Lieu, P K; Tanaka, S

    2016-01-01

    Characteristics of waste and wastewater management can affect material flows. Our research investigates the management of waste and wastewater in urban areas of developing countries and its effects on phosphorus flow based on a case study in Hue Citadel, Hue, Vietnam. One hundred households were interviewed to gain insight into domestic waste and wastewater management together with secondary data collection. Next, a phosphorus flow model was developed to quantify the phosphorus input and output in the area. The results showed that almost all wastewater generated in Hue Citadel was eventually discharged into water bodies and to the ground/groundwater. This led to most of the phosphorus output flowing into water bodies (41.2 kg P/(ha year)) and ground/groundwater (25.3 kg P/(ha year)). Sewage from the sewer system was the largest source of phosphorus loading into water bodies, while effluent from on-site sanitation systems was responsible for a major portion of phosphorus into the ground/groundwater. This elevated phosphorus loading is a serious issue in considering surface water and groundwater protection. PMID:26744936

  8. Relative Contributions of Phosphorus in High Elevation Sierra Nevada Lakes

    Science.gov (United States)

    Jensen, L. K.; McIntyre, B. M.; Lyons, R. A.

    2015-12-01

    High elevation lakes of the Sierra Nevada mountain range show signs of eutrophication due to increased phosphorus loading. Phosphorus is a major contributing factor to freshwater lake eutrophication when in excess. Three previously researched sources of phosphorus to high-elevation montane lakes include atmospheric deposition, internal loading from sediments, and excretions from non-native stocked fish. The goal of this research was to isolate the estimated phosphorus contributions from residential shoreline developments and stocked non-native fish. A steady-state phosphorus loading rate model was created to quantify relative phosphorus loading into two lakes in the Eastern Sierra Nevada: Convict and Silver Lake. A conglomerate control lake was created from Eastern Brook Lake in the Eastern Sierra Nevada, Pear Lake in the Southern Sierra Nevada, and Snowflake Lake in Canada. Both Convict and Silver Lakes contain stocked non-native trout species and Silver Lake also has ~25 vacation homes on its eastern shore. Seasonal steady-state total phosphorus concentrations were determined using EPA Method 365.2. Loading rate constants were calculated using loading rates from literature and corresponding concentrations. It was determined that as much as 42% of phosphorous to Silver Lake came from shoreline housing developments, and 24% came from stocked fish depending on the season. Previous studies showed much lower contributions from non-native fish.

  9. Preliminary analysis of phosphorus flow in Hue Citadel.

    Science.gov (United States)

    Anh, T N Q; Harada, H; Fujii, S; Anh, P N; Lieu, P K; Tanaka, S

    2016-01-01

    Characteristics of waste and wastewater management can affect material flows. Our research investigates the management of waste and wastewater in urban areas of developing countries and its effects on phosphorus flow based on a case study in Hue Citadel, Hue, Vietnam. One hundred households were interviewed to gain insight into domestic waste and wastewater management together with secondary data collection. Next, a phosphorus flow model was developed to quantify the phosphorus input and output in the area. The results showed that almost all wastewater generated in Hue Citadel was eventually discharged into water bodies and to the ground/groundwater. This led to most of the phosphorus output flowing into water bodies (41.2 kg P/(ha year)) and ground/groundwater (25.3 kg P/(ha year)). Sewage from the sewer system was the largest source of phosphorus loading into water bodies, while effluent from on-site sanitation systems was responsible for a major portion of phosphorus into the ground/groundwater. This elevated phosphorus loading is a serious issue in considering surface water and groundwater protection.

  10. Black phosphorus saturable absorber for ultrashort pulse generation

    International Nuclear Information System (INIS)

    Low-dimensional materials, due to their unique and versatile properties, are very interesting for numerous applications in electronics and optoelectronics. Recently rediscovered black phosphorus, with a graphite-like layered structure, can be effectively exfoliated up to the single atomic layer called phosphorene. Contrary to graphene, it possesses a direct band gap controllable by the number of stacked atomic layers. For those reasons, black phosphorus is now intensively investigated and can complement or replace graphene in various photonics and electronics applications. Here, we demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation. The mechanically exfoliated ∼300 nm thick layers of black phosphorus were transferred onto the fiber core, and under pulsed excitation at 1560 nm wavelength, its transmission increases by 4.6%. We have demonstrated that the saturable absorption of black phosphorus is polarization sensitive. The fabricated device was used to mode-lock an Er-doped fiber laser. The generated optical solitons with the 10.2 nm bandwidth and 272 fs duration were centered at 1550 nm. The obtained results unambiguously show that black phosphorus can be effectively used for ultrashort pulse generation with performances similar or even better than currently used graphene or carbon nanotubes. This application of black phosphorus proves its great potential to future practical use in photonics

  11. Dietary phosphorus requirement of young abalone Haliotis discus Hannai Ino

    Science.gov (United States)

    Tan, Bei-Ping; Mai, Kang-Sen; Liufu, Zhi-Guo

    2002-03-01

    An experiment was performed to determine the dietary phosphorus requirement of the young abalone, Haliotis discus hannai. Five semi-purified diets were formulated to provide a series of graded levels of dietary total phosphorus (0.23% 1.98) from monobasic potassium phosphate (KH2P04). The brown alga, Laminaria japonica, was used as a control diet. Similar size abalone were distributed in a single-pass, flow-through system using a completely randomized design with six treatments and three replicates each treatment. The abalone were hand-fed to satiation with appropriate diets in excess, once daily at 17:00. The feeding trial was run for 120-d. Survival rate and soft-body to shell ratio (SB/S) were constantly maintained regardless of dietary treatment. However, the weight gain rate (WGR), daily increment in shell length (DISL), muscle RNA to DNA ratio (RNA/DNA), carcass levels of lipid and protein, soft-body alkaline phosphatase (SBAKP), and phosphorus concentrations of whole body (WB) and soft body (SB) were significantly (ANOVA, P<0.05) affected by the dietary phosphorus level. The dietary phosphorus requirements of the abalone were evaluated from the WGR, DISL, and RNA/DNA ratio respectively, by using second-order polynomial regression analysis. Based on these criteria, about 1.0% 1.2% total dietary phosphorus, i.e. 0.9% 1.1% dietary available phosphorus is recommended for the maximum growth of the abalone.

  12. Black phosphorus saturable absorber for ultrashort pulse generation

    Energy Technology Data Exchange (ETDEWEB)

    Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, Wroclaw 50-370 (Poland); Macherzynski, W.; Paletko, P. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroclaw 50-372 (Poland)

    2015-08-03

    Low-dimensional materials, due to their unique and versatile properties, are very interesting for numerous applications in electronics and optoelectronics. Recently rediscovered black phosphorus, with a graphite-like layered structure, can be effectively exfoliated up to the single atomic layer called phosphorene. Contrary to graphene, it possesses a direct band gap controllable by the number of stacked atomic layers. For those reasons, black phosphorus is now intensively investigated and can complement or replace graphene in various photonics and electronics applications. Here, we demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation. The mechanically exfoliated ∼300 nm thick layers of black phosphorus were transferred onto the fiber core, and under pulsed excitation at 1560 nm wavelength, its transmission increases by 4.6%. We have demonstrated that the saturable absorption of black phosphorus is polarization sensitive. The fabricated device was used to mode-lock an Er-doped fiber laser. The generated optical solitons with the 10.2 nm bandwidth and 272 fs duration were centered at 1550 nm. The obtained results unambiguously show that black phosphorus can be effectively used for ultrashort pulse generation with performances similar or even better than currently used graphene or carbon nanotubes. This application of black phosphorus proves its great potential to future practical use in photonics.

  13. A Novel Approach to Bioleach Soluble Phosphorus from Rock Phosphate

    Institute of Scientific and Technical Information of China (English)

    池汝安; 肖春桥; 黄晓慧; 王存文; 吴元欣

    2007-01-01

    A novel approach to bioleach soluble phosphorus from rock phosphate, involving the bio-oxidation of pyrite by adaptated Acidithiobacillus ferrooxidans (At. f) and the product of sulfuric acid to dissolve rock phosphate, has been proposed in this paper. The soluble phosphorus could be leached more effectively in the presence of pyrite by At. f than that leached directly by sulfuric acid. The optimal technological parameters are presented. The highest phosphorus leaching rate is 9.00% when the culture substrate is the mixture of FeSO4·7H2O and pyrite, the phosphorus leaching rate is 8.00% when the initial pH and culture time are 2.5 and 5 d, respectively. The optimal rock phosphate particle size is 0.05 mm for the leaching of phosphorus. The bigger the grains of pyrite, the lower the phosphorus leaching rate. The bacterium At. f should be appropriately adaptated, which makes it easier to bioleach soluble phosphorus from rock phosphate.

  14. Evaluation of a Membrane Biological Reactor for Reclaiming Water, Alkalinity, Salts, Phosphorus, and Protein Contained in a High-Strength Aquacultural Wastewater

    Science.gov (United States)

    The capacity of a membrane biological reactor to provide nitrification, denitrification, and enhanced biological phosphorus removal of a high-strength aquaculture backwash flow (control condition), or the same flow amended with 100 mg/L of NO3-N and 3 mg/L of dissolved P (test condition), was assess...

  15. Investigation of charges carrier density in phosphorus and boron doped SiNx:H layers for crystalline silicon solar cells

    International Nuclear Information System (INIS)

    Highlights: ► We investigate the properties of phosphorus and boron-doped silicon nitride films. ► Phosphorus-doped layers yield higher lifetimes than undoped ones. ► The fixed charges density decreases when increasing the films phosphorus content. ► Boron-doped films feature very low lifetimes. ► These doped layers are of particular interest for crystalline silicon solar cells. -- Abstract: Dielectric layers are of major importance in crystalline silicon solar cells processing, especially as anti-reflection coatings and for surface passivation purposes. In this paper we investigate the fixed charge densities (Qfix) and the effective lifetimes (τeff) of phosphorus (P) and boron (B) doped silicon nitride layers deposited by plasma-enhanced chemical vapour deposition. P-doped layers exhibit a higher τeff than standard undoped layers. In contrast, B-doped layers exhibit lower τeff. A strong Qfix decrease is to be seen when increasing the P content within the film. Based on numerical simulations we also demonstrate that the passivation obtained with P- and B-doped layers are limited by the interface states rather than by the fixed charges

  16. Simultaneous nitrification, denitrification and phosphorus removal (SNDPR) in a full-scale water reclamation plant located in warm climate.

    Science.gov (United States)

    Yang, Qin; Shen, Nan; Lee, Zarraz M-P; Xu, Guangjing; Cao, Yeshi; Kwok, Beehong; Lay, Winson; Liu, Yu; Zhou, Yan

    2016-01-01

    The combination of simultaneous nitrification-denitrification (SND) with enhanced biological phosphorus removal (EBPR) provides a more efficient and economically viable option for nutrient removal from municipal wastewater compared to conventional two-step nitrification-denitrification. This study analyzed the nutrients (N and P) profiles in a full-scale municipal wastewater reclamation plant (WRP) located in the tropical region, in which more than 90% of nitrogen was removed. Interestingly, average SND efficiency in aerobic zones was found to be up to 50%, whereas phosphorus profile displayed a clear cyclic release and uptake pattern with a phosphorus removal efficiency of up to 76%. The capability of sludge to perform SND and EBPR was further confirmed through a series of batch experiments. Microbial analysis revealed the presence of Accumulibacter and Tetrasphaera phosphate accumulating organisms in the plant, while few glycogen accumulating organisms (GAO) was observed. This study showed the significant occurrence of combined SND and EBPR, known as simultaneous nitrification, denitrification and phosphorus removal (SNDPR), in the studied WRP under warm climate. The possible causes behind the observed SNDPR were also discussed.

  17. Simultaneous nitrification, denitrification and phosphorus removal (SNDPR) in a full-scale water reclamation plant located in warm climate.

    Science.gov (United States)

    Yang, Qin; Shen, Nan; Lee, Zarraz M-P; Xu, Guangjing; Cao, Yeshi; Kwok, Beehong; Lay, Winson; Liu, Yu; Zhou, Yan

    2016-01-01

    The combination of simultaneous nitrification-denitrification (SND) with enhanced biological phosphorus removal (EBPR) provides a more efficient and economically viable option for nutrient removal from municipal wastewater compared to conventional two-step nitrification-denitrification. This study analyzed the nutrients (N and P) profiles in a full-scale municipal wastewater reclamation plant (WRP) located in the tropical region, in which more than 90% of nitrogen was removed. Interestingly, average SND efficiency in aerobic zones was found to be up to 50%, whereas phosphorus profile displayed a clear cyclic release and uptake pattern with a phosphorus removal efficiency of up to 76%. The capability of sludge to perform SND and EBPR was further confirmed through a series of batch experiments. Microbial analysis revealed the presence of Accumulibacter and Tetrasphaera phosphate accumulating organisms in the plant, while few glycogen accumulating organisms (GAO) was observed. This study showed the significant occurrence of combined SND and EBPR, known as simultaneous nitrification, denitrification and phosphorus removal (SNDPR), in the studied WRP under warm climate. The possible causes behind the observed SNDPR were also discussed. PMID:27438250

  18. COMPARISON OF SOIL TEST METHODS FOR AVAILABLE PHOSPHORUS IN COMMON CALCAREOUS BLACK SOIL

    Directory of Open Access Journals (Sweden)

    Biryukova O. A.

    2014-11-01

    Full Text Available The article presents a comparative analysis of the results on available phosphorus measurements in common black soils using the Machigin and Olsen methods. The relationships between maize productivity and soil available phosphorus and also between phosphorus concentrations in the above-ground plant parts and soil available phosphorus were identified at various stages of crop development

  19. COMPARISON OF SOIL TEST METHODS FOR AVAILABLE PHOSPHORUS IN COMMON CALCAREOUS BLACK SOIL

    OpenAIRE

    Biryukova O. A.; Bozhkov D. V.; Nosov V. V.

    2014-01-01

    The article presents a comparative analysis of the results on available phosphorus measurements in common black soils using the Machigin and Olsen methods. The relationships between maize productivity and soil available phosphorus and also between phosphorus concentrations in the above-ground plant parts and soil available phosphorus were identified at various stages of crop development

  20. Impact of fertilizer phosphorus application on phosphorus release kinetics in some calcareous soils

    Science.gov (United States)

    Hosseinpur, A. R.; Biabanaki, F. S.

    2009-01-01

    Phosphate reactions and retention in the soil are of paramount importance from the perspective of plant nutrition and fertilizer use efficiency. The objective of this work was to study the kinetics of phosphorus (P) desorption in different soils of Hamadan in fertilized and unfertilized soils. Soils were fertilized with 200 mg P kg-1. Fertilized and unfertilized soils were incubated at 25 ± 1°C for 6 months. After that, release of P was studied by successive extraction with 0.5 M NaHCO3 over a period of 1,752 h. The results showed that phosphorus desorption from the fertilized and unfertilized soils began with a fast initial reaction, followed by a slow secondary reaction. The amount of P released after 1,752 h in fertilized and unfertilized soils ranged from 457 to 762.4 and 309.6 to 586.7 mg kg-1, respectively. The kinetics of cumulative P release was evaluated using the five kinetic equations. Phosphorus desorption kinetics were best described by parabolic diffusion law, first order, and power function equations. Rate constants of these equations were higher in fertilized than unfertilized soils. Results from this study indicate that release rate of P plays a significant role in supplying available P and released P in runoff.

  1. Mass transfer of phosphorus in high-phosphorus hot-metal refining

    Institute of Scientific and Technical Information of China (English)

    Jiang Diao; Xuan Liu,; Tao Zhang; Bing Xie

    2015-01-01

    Mass transfer of phosphorus in high-phosphorus hot-metal refining was investigated using CaO−FetO−SiO2 slags at 1623 K. Based on a two-film theory kinetic model and experimental results, it was found that the overall mass transfer coefficient, which includes the effects of mass transfer in both the slag phase and metal phase, is in the range of 0.0047 to 0.0240 cm/s. With the addition of a small amount of fluxing agents Al2O3 or Na2O into the slag, the overall mass transfer coefficient has an obvious increase. Silicon content in the hot metal also influences the overall mass transfer coefficient. The overall mass transfer coefficient in the lower [Si] heat is much higher than that in the higher [Si] heat. It is concluded that both fluxing agents and lower [Si] hot metal facilitate mass transfer of phosphorus in liquid phases. Fur-thermore, the addition of Na2O could also prevent rephosphorization at the end of the experiment.

  2. Organ-specific phosphorus-allocation patterns and transcript profiles linked to phosphorus efficiency in two contrasting wheat genotypes.

    Science.gov (United States)

    Aziz, Tariq; Finnegan, Patrick M; Lambers, Hans; Jost, Ricarda

    2014-04-01

    Recent studies have identified genotypic variation in phosphorus (P) efficiency, but rarely have the underlying mechanisms been described at the molecular level. We demonstrate that the highly P-efficient wheat (Triticum aestivum L.) cultivar Chinese 80-55 maintains higher inorganic phosphate (Pi ) concentrations in all organs upon Pi withdrawal in combination with higher Pi acquisition in the presence of Pi when compared with the less-efficient cultivar Machete. These findings correlated with differential organ-specific expression of Pi transporters TaPHT1;2, TaPHT1;5, TaPHT1;8, TaPHT2;1 and H(+) -ATPase TaHa1. Observed transcript level differences between the cultivars suggest that higher de novo phospholipid biosynthetic activities in Pi -limited elongating basal leaf sections are another crucial adaptation in Chinese 80-55 for sustaining growth upon Pi withdrawal. These activities may be supported through enhanced breakdown of starch in Chinese 80-55 stems as suggested by higher TaGPho1 transcript levels. Chinese 80-55 fine roots on the other hand show strong suppression of transcripts involved in glycolysis, transcriptional regulation and ribosomal activities. Our work reveals major differences in the way the two contrasting cultivars allocate Pi and organic P compounds between source and sink tissues and in the acclimation of their metabolism to changes in Pi availability.

  3. Remaining Phosphorus Estimate Through Multiple Regression Analysis

    Institute of Scientific and Technical Information of China (English)

    M. E. ALVES; A. LAVORENTI

    2006-01-01

    The remaining phosphorus (Prem), P concentration that remains in solution after shaking soil with 0.01 mol L-1 CaCl2 containing 60 μg mL-1 P, is a very useful index for studies related to the chemistry of variable charge soils. Although the Prem determination is a simple procedure, the possibility of estimating accurate values of this index from easily and/or routinely determined soil properties can be very useful for practical purposes. The present research evaluated the Premestimation through multiple regression analysis in which routinely determined soil chemical data, soil clay content and soil pH measured in 1 mol L-1 NaF (pHNaF) figured as Prem predictor variables. The Prem can be estimated with acceptable accuracy using the above-mentioned approach, and PHNaF not only substitutes for clay content as a predictor variable but also confers more accuracy to the Prem estimates.

  4. Recovery of gallium from phosphorus industry flue

    Institute of Scientific and Technical Information of China (English)

    许可; 邓彤; 戴玉杰; 王静

    2004-01-01

    The flue dust generated during electric furnace production of elemental phosphorus was investigated for the recovery of gallium. Then the flue dust was slurried with water and blended with concentrated sulfuric acid, followed by ageing. The gallium in the dust was thereby converted to soluble sulfate. The factors affecting the dust curing were investigated to understand the process chemistry of the pretreatment. The optimal curing conditions are determined as follows: the mass ratio of dust to water and acid is 1: 1: 1, ageing temperature and time are 200 ℃ and 2 h, respectively. Almost all the gallium available to acid dissolution in the dust, about 900%00 gallium, can be extracted by leaching the cured dust at 80 ℃ for 1 h.

  5. Phosphorus removal using novel crystallisation technology.

    Science.gov (United States)

    Wood, K; Wood, G; Prokop, D; Lewyille, F

    2006-01-01

    A soy protein manufacturing facility was faced with the challenge of reducing its effluent phosphorus (P) content from 20-50 mg L(-1) down to salt levels to comply with discharge and receiving water requirements. A number of biological and chemical P removal technologies previously evaluated either failed to achieve the new standards or would have produced prohibitive amounts of residual sludge and unacceptably high effluent salt concentrations. Lime precipitation, utilising a novel crystallisation technology, was demonstrated through on-site pilot testing to meet the process objectives. It is capable of achieving the required P removal at pH 10 while not increasing soluble salts and producing rapid settling and filterable particles. Also, minimal carbonate removal was observed with residual solids generation being only 40% of a complete lime softening reaction. This paper describes the technical evaluation that led to the full-scale treatment system that was put into operation in late 2005. PMID:16889253

  6. Agricultural trade and the global phosphorus cycle

    Science.gov (United States)

    Schipanski, M.; Bennett, E.; Riskin, S.; Porder, S.

    2012-12-01

    Trends of increasing agricultural trade, increased concentration of livestock production systems, and increased human consumption of livestock products influence the distribution of nutrients across the global landscape. Phosphorus (P) represents a unique management challenge as we are rapidly depleting mineable reserves of this essential and non-renewable resource. At the same time, its overuse can lead to pollution of aquatic ecosystems. We analyzed the relative contributions of food crop, feed crop, and livestock product trade to P flows through agricultural soils for twelve countries from 1961 to 2007. We then used case studies of P fertilizer use in the world's three major soybean export regions: Iowa (USA), Mato Grosso (Brazil), and Buenos Aires (Argentina) to examine the influence of historical P management and soil types on agriculture's environmental consequences. Due to the intensification of agricultural production, average soil surface P balances more than tripled from 6 to 21 kg P per ha between 1961 and 2007 for the twelve study countries. Consequently, countries that are primarily agricultural exporters carried increased risks for water pollution or, for Argentina, reduced soil fertility due to soil P mining to support exports. In 2007, nations imported food and feed from regions with higher apparent P fertilizer use efficiencies than if those crops were produced domestically. However, this was largely because imports were sourced from regions depleting soil P resources to support export crop production. In addition, the pattern of regional specialization and intensification of production systems also reduced the potential to recycle P resources, with greater implications for livestock production than crop production. In a globalizing world, it will be increasingly important to integrate biophysical constraints of our natural resources and environmental impacts of agricultural systems into trade policy and agreements and to develop mechanisms that

  7. Organic Phosphorus in the Deep Subseafloor Environment

    Science.gov (United States)

    Defforey, D.; Paytan, A.

    2014-12-01

    Phosphorus (P) is a macronutrient involved both in functional and structural components of all living cells. This makes it an essential nutrient for life, including microbial life in the deep subseafloor habitat. P availability in this environment is limited since organic matter is scarce and P is thought to be mainly present in refractory mineral phases. However, recent estimates suggest that the deep biosphere may contain up to 1% of Earth's total biomass, which implies that microorganisms may possess mechanisms to harvest recalcitrant phosphorus compounds in this environment. In addition, the role of the organic P pool in this setting is poorly understood and could be of great importance should it represent an important P pool fueling the deep biosphere. This study aims to identify and quantify organic P compounds in open ocean sediments using our newly developed sequential extraction procedure for 31P nuclear magnetic resonance spectroscopy (31P NMR). This method amplifies the signal of organic P in spectra by increasing its concentration and quantitatively removing the majority of inorganic P. Briefly, P bound to iron oxyhydroxides is removed from sediment samples during a reductive step; then, P in authigenic and biogenic apatite is solubilized over the course of an extraction in an acidic buffer. These two steps remove the majority of inorganic P from the sample. Lastly, the residue is extracted in 0.25M NaOH+ 0.05M Na2EDTA and the supernatant is frozen and lyophilized prior to 31P NMR analysis. This method will be applied to sediment samples from North Pond (IODP expedition 336), an isolated sediment pond on the western flank of the Mid-Atlantic ridge. This work will provide valuable insight into the diagenetic processes affecting organic P in open ocean sediments and into possible nutrient sources to the deep biosphere.

  8. Layer Tunable Third-Harmonic Generation in Multilayer Black Phosphorus

    CERN Document Server

    Youngblood, Nathan; Nemilentsau, Andrei; Low, Tony; Li, Mo

    2016-01-01

    Black phosphorus has been the subject of growing interest due to its unique band structure that is both layer dependent and anisotropic. While many have studied the linear optical response of black phosphorus, the nonlinear response has remained relatively unexplored. Here we report on the observation of third-harmonic generation in black phosphorus using an ultrafast near-IR laser and measure chi(3) experimentally for the first time. It was found that chi(3) is highly dependent on both the incident polarization and the number of layers present.

  9. Induced mutation-facilitated genetic studies of seed phosphorus

    International Nuclear Information System (INIS)

    Both the chemical composition and total amount of seed phosphorus (P) are important to the end-use quality of cereal and legume seed crops, whether for use in human foods or animal feeds. They are also important to the management of P in agricultural production, and to the long-term sustainability of that production. About 75% (±10%) of seed total P is found as phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate). Mutations that block the synthesis or accumulation of phytic acid during seed development, often referred to as low phytic acid (lpa) mutations, have been isolated in maize (Zea mays L.), barley (Hordeum vulgare L.), rice (Oryza sativa L.), wheat (Triticum aestivum L.) and soybean (Glycine max L. (Merr.). Chromosomal mapping has identified as many as six non-allelic lpa loci in a single species (barley). Studies of lpa mutants has enhanced knowledge of the genes and proteins important to phytic acid P metabolism. While there has been substantial research into the biology of P uptake by plants, there has been little progress in the genetics of seed total P. Genetics that either decreases or increases seed total P might be of value for both enhancing the end-use quality of seed crops and for optimizing the utilization of P during agricultural production. As proof-of-principle, homozygosity for recessive alleles of barley lpa1 both blocks seed phytic acid accumulation by 50% and reduces seed total P by 15%, while having little impact on yield. The current status of lpa genetics and current efforts at isolating 'seed-total P' mutants, using both forward and reverse genetics approaches, will be described. (author)

  10. Induced Mutation-Facilitated Genetic Studies of Seed Phosphorus

    International Nuclear Information System (INIS)

    Both the chemical composition and total amount of seed phosphorus (P) are important to the end-use quality of cereal and legume seed crops, whether for use in human foods or animal feeds. They are also important to the management of P in agricultural production, and to the long-term sustainability of that production. About 75% (±10%) of seed total P is found as phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate). Mutations that block the synthesis or accumulation of phytic acid during seed development, often referred to as low phytic acid (lpa) mutations, have been isolated in maize (Zea mays L.), barley (Hordeum vulgare L.), rice (Oryza sativa L.), wheat (Triticum aestivum L.) and soybean (Glycine max L. (Merr.). Chromosomal mapping has identified as many as six non-allelic lpa loci in a single species (barley). Studies of lpa mutants has enhanced knowledge of the genes and proteins important to phytic acid P metabolism. While there has been substantial research into the biology of P uptake by plants, there has been little progress in the genetics of seed total P. Genetic factors that either decrease or increase seed total P might be of value for both enhancing the end-use quality of seed crops and for optimizing the utilization of P during agricultural production. As proof-of-principle, homozygosity for recessive alleles of barley lpa 1 both blocks seed phytic acid accumulation by 50% and reduces seed total P by 15%, while having little impact on yield. The current status of lpa genetics and current efforts at isolating 'seed-total P' mutants, using both forward and reverse genetics approaches, will be described. (author)

  11. Roasting-induced phase change and its influence on phosphorus removal through acid leaching for high-phosphorus iron ore

    Science.gov (United States)

    Yang, Min; Zhu, Qing-shan; Fan, Chuan-lin; Xie, Zhao-hui; Li, Hong-zhong

    2015-04-01

    In the present study, roasting-induced phase change and its influence on phosphorus removal via leaching has been investigated for high-phosphorus iron ore. The findings indicate that phosphorus in the ore is associated with goethite and exists mainly in amorphous Fe3PO7 phase. The phosphorus remains in the amorphous phase after being roasted below 300°C. Grattarolaite (Fe3PO7) is found in samples roasted at 600-700°C, revealing that phosphorus phase is transformed from the amorphous form to crystalline grattarolaite during roasting. Leaching tests on synthesized pure grattarolaite reveal a low rate of phosphorus removal by sulfuric acid leaching. When the roasting temperature is higher than 800°C, grattarolaite is found to react with alumina to form aluminum phosphate, and the reactivity of grattarolaite with alumina increases with increasing roasting temperature. Consequently, the rate of phosphorus removal also increases with increasing roasting temperature due to the formation of acid-soluble aluminum phosphate.

  12. Advanced phosphorus recovery using a novel SBR system with granular sludge in simultaneous nitrification, denitrification and phosphorus removal process.

    Science.gov (United States)

    Lu, Yong-Ze; Wang, Hou-Feng; Kotsopoulos, Thomas A; Zeng, Raymond J

    2016-05-01

    In this study, a novel process for phosphorus (P) recovery without excess sludge production from granular sludge in simultaneous nitrification-denitrification and P removal (SNDPR) system is presented. Aerobic microbial granules were successfully cultivated in an alternating aerobic-anaerobic sequencing batch reactor (SBR) for removing P and nitrogen (N). Dense and stable granular sludge was created, and the SBR system showed good performance in terms of P and N removal. The removal efficiency was approximately 65.22 % for N, and P was completely removed under stable operating conditions. Afterward, new operating conditions were applied in order to enhance P recovering without excess sludge production. The initial SBR system was equipped with a batch reactor and a non-woven cloth filter, and 1.37 g of CH3COONa·3H2O was added to the batch reactor after mixing it with 1 L of sludge derived from the SBR reactor to enhance P release in the liquid fraction, this comprises the new system configuration. Under the new operating conditions, 93.19 % of the P contained in wastewater was released in the liquid fraction as concentrated orthophosphate from part of granular sludge. This amount of P could be efficiently recovered in the form of struvite. Meanwhile, a deterioration of the denitrification efficiency was observed and the granules were disintegrated into smaller particles. The biomass concentration in the system increased firstly and then maintained at 4.0 ± 0.15 gVSS/L afterward. These results indicate that this P recovery operating (PRO) mode is a promising method to recover P in a SNDPR system with granular sludge. In addition, new insights into the granule transformation when confronted with high chemical oxygen demand (COD) load were provided. PMID:26728017

  13. Contrasting effects of exogenous phosphorus application on N2O emissions from two tropical forest soils with contrasting phosphorus availability.

    Science.gov (United States)

    Mori, Taiki; Yokoyama, Daiki; Kitayama, Kanehiro

    2016-01-01

    An incubation study was conducted to test the effects of phosphorus (P) addition on nitrous oxide (N2O) emissions from the soils taken from two tropical rain forests established on different parent materials [meta-sedimentary (MS) and ultrabasic (UB) rock] on Mt. Kinabalu, Borneo. Earlier studies suggest that the forest on UB soils is more strongly limited by P than that on MS soils is. In MS soils, P addition significantly reduced N2O emissions. Since neither ammonium (NH4 (+)) nor nitrate (NO3 (-)) contents were reduced by P addition, we assumed that the decrease in N2O emissions were not due to the previously-reported mechanism: P addition stimulated microbial nitrogen (N) immobilization and collateral inorganic N consumption, reducing resources for producing N2O. Since P addition enhanced the ratios of microbial biomass to CO2 and N2O emissions (indicators of nitrifying and/or denitrifying respiratory efficiency), it was suggested that the N required for the respiration of nitrifying and/or denitrifying bacteria was reduced, leading to reduced N2O emissions. On the other hand, P addition had no effects on N2O emissions in UB soils. The respiratory efficiency did not change significantly by P addition, possibly because the microbial community in the highly-P-depleted UB soils shifted by P addition, with which the enhancement of respiration efficiency did not co-vary. We concluded that (1) P addition may control N2O emissions through increasing respiratory efficiency, and (2) the effects may be different depending on the differences in P availability. PMID:27536520

  14. Chemical vapor deposition of amorphous ruthenium-phosphorus alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Shin Jinhong [Texas Materials Institute, University of Texas at Austin, Austin, TX 78750 (United States); Waheed, Abdul [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712 (United States); Winkenwerder, Wyatt A. [Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 (United States); Kim, Hyun-Woo [Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 (United States); Agapiou, Kyriacos [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712 (United States); Jones, Richard A. [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712 (United States); Hwang, Gyeong S. [Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 (United States); Ekerdt, John G. [Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 (United States)]. E-mail: ekerdt@che.utexas.edu

    2007-05-07

    Chemical vapor deposition growth of amorphous ruthenium-phosphorus films on SiO{sub 2} containing {approx} 15% phosphorus is reported. cis-Ruthenium(II)dihydridotetrakis-(trimethylphosphine), cis-RuH{sub 2}(PMe{sub 3}){sub 4} (Me = CH{sub 3}) was used at growth temperatures ranging from 525 to 575 K. Both Ru and P are zero-valent. The films are metastable, becoming increasingly more polycrystalline upon annealing to 775 and 975 K. Surface studies illustrate that demethylation is quite efficient near 560 K. Precursor adsorption at 135 K or 210 K and heating reveal the precursor undergoes a complex decomposition process in which the hydride and trimethylphosphine ligands are lost at temperatures as low at 280 K. Phosphorus and its manner of incorporation appear responsible for the amorphous-like character. Molecular dynamics simulations are presented to suggest the local structure in the films and the causes for phosphorus stabilizing the amorphous phase.

  15. Black phosphorus photodetector for multispectral, high-resolution imaging.

    Science.gov (United States)

    Engel, Michael; Steiner, Mathias; Avouris, Phaedon

    2014-11-12

    Black phosphorus is a layered semiconductor that is intensely researched in view of applications in optoelectronics. In this letter, we investigate a multilayer black phosphorus photodetector that is capable of acquiring high-contrast (V > 0.9) images both in the visible (λVIS = 532 nm) as well as in the infrared (λIR = 1550 nm) spectral regime. In a first step, by using photocurrent microscopy, we map the active area of the device and we characterize responsivity and gain. In a second step, by deploying the black phosphorus device as a point-like detector in a confocal microsope setup, we acquire diffraction-limited optical images with submicron resolution. The results demonstrate the usefulness of black phosphorus as an optoelectronic material for hyperspectral imaging applications.

  16. Dietary phosphorus requirement of pejerrey fingerlings (Odontesthes bonariensis

    Directory of Open Access Journals (Sweden)

    Cleber Bastos Rocha

    2014-02-01

    Full Text Available To determine the available phosphorus requirement of pejerrey fish, four semi-purified diets were formulated to contain increasing available phosphorus levels (0.90, 2.7, 5.7 and 8.3 g/kg. Each diet was assigned to groups of 10 fish with average weight of 1.26±0.17 g, distributed into a completely randomized design with four treatments and four replications. Fish were fed at a rate of 10% total biomass four times a day for 60 days. The parameters productive performance, body chemical composition and mineral composition of bones and scales were evaluated. The best productive performance of fingerlings was obtained with the diet containing 4.3 g/kg available phosphorus. The average level of 6.3 g/kg available phosphorus promotes better mineralization of bones and scales in pejerrey fish.

  17. Phosphorus limitation on bacterial regrowth in drinking water

    Institute of Scientific and Technical Information of China (English)

    SANG Jun-qiang; ZHANG Xi-hui; YU Guo-zhong; WANG Zhan-sheng

    2003-01-01

    Assimilable organic carbon (AOC) test and bacterial regrowth potential (BRP) analysis were used to investigate the effect of phosphorus on bacterial regrowth in the drinking water that was made from some raw water taken from a reservoir located in northern China. It was shown that AOC of the drinking water samples increased by 43.9%-59.6% and BRP increased by 100%-235% when 50 μg/L PO3-4-P(as NaH2 PO4 ) was added alone to the drinking water samples. This result was clear evidence of phosphorus limitation on bacteria regrowth in the drinking water. This investigation indicated the importance of phosphorus in ensuring biological stability of drinking water and offered a novel possible option to restrict microbial regrowth in drinking water distribution system by applying appropriate technologies to remove phosphorus efficiently from drinking water in China.

  18. Selective nitration and bromination of surprisingly ruffled phosphorus corroles.

    Science.gov (United States)

    Pomarico, Giuseppe; Tortora, Luca; Fronczek, Frank R; Smith, Kevin M; Paolesse, Roberto

    2016-05-01

    Phosphorus complexes of corrole have recently attracted increasing interest since these compounds can be easily prepared in good yields, are stable, and show unusual optical properties. For these reasons, phosphorus corroles represent a class of interesting compounds to be exploited in the field of material science or for biomedical investigations and the definition of synthetic pathways for their functionalization is an important step to optimize their properties for various applications. We report here the reactivity of the phosphorus complex of 5,10,15-tritolylcorrole in the nitration or bromination reaction. Both these attempts were successful, allowing the preparation of substituted phosphorus corroles, which can be used as intermediates of more complex architectures endowed with useful properties. Furthermore, the crystallographic characterization of both complexes shows that they have an unusual ruffled geometry of the corrole core, a conformation that has not been considered possible for such a macrocycle.

  19. A single phosphorus treatment doubles growth of cyanobacterial lichen transplants.

    Science.gov (United States)

    McCune, Bruce; Caldwell, Bruce A

    2009-02-01

    Lichens are reputedly slow growing and become unhealthy or die in response to supplements of the usual limiting resources, such as water and nitrogen. We found, however, that the tripartite cyanobacterial lichen Lobaria pulmonaria doubled in annual biomass growth after a single 20-minute immersion in a phosphorus solution (K2HPO4), as compared to controls receiving no supplemental phosphorus. This stimulation of cyanolichens by phosphorus has direct relevance to community and population ecology of lichens, including improving models of lichen performance in relation to air quality, improving forest management practices affecting old-growth associated cyanolichens, and understanding the distribution and abundance of cyanolichens on the landscape. Phosphorus may be as important a stimulant to cyanobacterial-rich lichen communities as it is to cyanobacteria in aquatic ecosystems. PMID:19323240

  20. Penta-coordinated phosphorus structure analysis on kinases

    Institute of Scientific and Technical Information of China (English)

    LI; Wu; MA; Yuan; ZHAO; Yufen

    2004-01-01

    In this paper, based on the known crystal structures of Square Pyramid (SP) and Trigonal Bipyramid (TBP) penta-coordinated phosphorus compounds containing amino acid side chains, such as amino, carboxyl, hydroxyl or thiol, a software designed to survey the P(5)-Structure of phosphorylated proteins. By this software, it was found that 382 of 398 phosphorus-related kinases (96%) from current PDB could go through the penta-coordinated phosphorus transition state or intermediate. For example, in protein 1HE8, amino group in Lysine16was within 3.58 A from the phosphorus atom, and a potential TBP structure consisting GNP2 and Nz could be overlapped with an authentic TBP with an RMSD value of 0.71 A.

  1. Phosphorus Removal from Silicon by Vacuum Refining and Directional Solidification

    Science.gov (United States)

    Jiang, Dachuan; Ren, Shiqiang; Shi, Shuang; Dong, Wei; Qiu, Jieshan; TAN, Yi; Li, Jiayan

    2014-02-01

    Silicon is widely used as a raw material for production of solar cells. As a major impurity in silicon, phosphorus must be removed to 1 × 10-5 wt.%. In the present study, based on the distribution of phosphorus in a silicon ingot obtained by vacuum refining and directional solidification, the mechanism for removal of phosphorus from silicon is investigated. The results show that the distribution is controlled not only by segregation at the solid-liquid interface but also by evaporation at the gas-liquid interface, showing some deviation from Scheil's equation. A modified model which considers both segregation and evaporation is used to simulate the distribution, matching quite well with the experimental results. The temperature and solidification rate are two important parameters that affect the overall mass transfer coefficient and the effective segregation coefficient and thus the distribution of phosphorus. A high removal efficiency and a homogeneous distribution can be obtained by adjusting these two parameters.

  2. 31P NMR Study on Some Phosphorus-Containing Compounds

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    31P NMR has become a widely applied spectroscopic probe of the structure of phosphorus-containing compounds. Meanwhile, the application of 31P NMR has been rapidly expanded to biochemistry and medicinal chemistry of phosphorus-containing compounds because the growing importance of the phosphorus compounds is now widely realized. We report here the results of 31P NMR study on some phosphorus-containing compounds, namely, O-alkyl O-4-nitrophenyl methyl phosphonates with different alkyl chain-length (MePO-n), 4-nitrophenyl alkylphenylphosphinates with different alkyl chain-length (PhP-n), diethyl phosphono- acetonitrile anion and diethyl phosphite anion . Our results indicate that 31P NMR can not only be applied to not only the study of the hydrolytic reactions of MePO-8 and PhP-8 but also be applied to the study of the presence of the anions of diethylphosphonoacetonitrile and diethyl phosphite in nucleophilic reactions.

  3. Calcination-Digestion-Desliming of Phosphorus Ore Bearing Rare Earth

    Institute of Scientific and Technical Information of China (English)

    Zhang Qin; Zhang Jie; Wang Jing; Qiu Yue qin

    2004-01-01

    The recoveries of phosphorus and RE of ore from Zhijin in Guizhou were studied.The influences of the calcination temperature, resident time, the digested time and water volume of the calcinating on concentrate yield by desliming were also investigated by orthogonal design.Appropriate calcination temperature is initial condition that makes carbonate mineral decomposition.The recovery of phosphorus is 83.02% and rare earth is 90.56% in phosphorus concentrate when calcined temperature is 900 ℃, other conditions include: calcined time is 30 min, digestion water volume is 300 ml, digestion time is 20 min.The results show that the pre-treatment of the ore is favorable for the separation and enrichment of rare earth from phosphorus ore, and a process of calcination-digestion-desliming was promised.

  4. Virus production in phosphorus-limited Micromonas pusilla stimulated by a supply of naturally low concentrations of different phosphorus sources, far into the lytic cycle.

    Science.gov (United States)

    Maat, Douwe S; van Bleijswijk, Judith D L; Witte, Harry J; Brussaard, Corina P D

    2016-09-01

    Earlier studies show that the proliferation of phytoplankton viruses can be inhibited by depletion of soluble reactive phosphorus (SRP; orthophosphate). In natural marine waters, phytoplankton phosphorus (P) availability is, however, largely determined by the supply rate of SRP (e.g. through remineralization) and potentially by the source of P as well (i.e. the utilization of soluble non-reactive P; SNP). Here we show how a steady low supply of P (mimicking natural P recycling) to virally infected P-limited Micromonas pusilla stimulates virus proliferation. Independent of the degree of P limitation prior to infection (0.32 and 0.97μmax chemostat cultures), SRP supply resulted in 2-fold higher viral burst sizes (viruses lysed per host cell) as compared with no addition (P starvation). Delaying these spikes during the infection cycle showed that the added SRP was utilized for extra M. pusilla virus (MpV) production far into the lytic cycle (18 h post-infection). Moreover, P-limited M. pusilla utilized several SNP compounds with high efficiency and with the same extent of burst size stimulation as for SRP. Finally, addition of virus-free MpV lysate (representing a complex SNP mixture) to newly infected cells enhanced MpV production, implicating host-associated alkaline phosphatase activity, and highlighting its important role in oligotrophic environments. PMID:27316561

  5. Electrodialytic recovery of phosphorus from chemically precipitated sewage sludge ashes

    DEFF Research Database (Denmark)

    Parés Viader, Raimon; Jensen, Pernille Erland; Ottosen, Lisbeth M.;

    Phosphorus scarcity requires improved recover and reuse of urban sources; the recycling of this nutrient from sewage sludge has become increasingly important in the last years. Using an innovative electrodialytic process, the present study shows the potential for P separation from Fe and Al preci...... precipitated sewage sludge ash using this technique, with a recovery rate of around 70%. Furthermore, heavy metals were removed from the phosphorous fraction, producing a pure and safe phosphorus source in the end....

  6. Electrodialytic recovery of phosphorus from chemically precipitated sewage sludge ashes

    DEFF Research Database (Denmark)

    Viader, Raimon Parés; Erland Jensen, Pernille; Ottosen, Lisbeth M.;

    Phosphorus scarcity requires improved recover and reuse of urban sources; the recycling of this nutrient from sewage sludge has become increasingly important in the last years. Using an innovative electrodialytic process, the present study shows the potential for P separation from Fe and Al preci...... precipitated sewage sludge ash using this technique, with a recovery rate of around 70%. Furthermore, heavy metals were removed from the phosphorous fraction, producing a pure and safe phosphorus source in the end...

  7. Global baseline data on phosphorus pollution of large lakes

    Science.gov (United States)

    Fink, Gabriel; Flörke, Martina; Alcamo, Joseph

    2016-04-01

    Lakes are exposed to harmful eutrophication which is the most concerning water quality issue on global scale. Eutrophication is caused by phosphorous pollution in most lakes. Hence, global consistent base line data on phosphorus loadings are needed to assess future sustainable development. We used the modeling framework WaterGAP3 to calculate present total phosphorus loadings to the world's largest lakes. Estimates of modeled total phosphorus (TP) loadings as well as the contributions of different sectors were successfully validated against measured data. Based on these findings, annual total phosphorus loadings to lakes were calculated for diffuse and point sources according to the different sectors domestic, manufacturing, urban surface runoff, agriculture and background for the time period 1990 to 2010. Our results show high phosphorus loadings into lakes in southern latitudes. On global average, industrial fertilizer is the main anthropogenic source while background loadings are low in comparison. Nevertheless, both features indicate a high potential to reduce the exposure to eutrophication in lakes which are faced with high phosphor inputs. The global average of TP loadings was 7% higher in the time period 2005-2010 than in the period 1990-1995. The global average in 2005-2010 results from an increase in TP loadings of 79% in South America, which was dampened by a decrease in Europe, North America, and Asia. Chinese lakes were exposed to massive increasing phosphorus loadings, too. Both increasing and decreasing trends are caused primarily by changing industrial fertilizer application rates. In conclusion, this study provides a consistent and model based synopsis of global trends and sources of phosphorus loadings to large lakes. The estimates of phosphorus pollution of lakes present a basis for assessing and managing the global eutrophication problem.

  8. TEMPORAL AND SPATIAL DISTRIBUTION OF PHOSPHORUS IN THE XIANGXI RIVER

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Phosphorus is an essential and oftenlimiting nutrientin both marine andfreshwater ecosystems,yetits oversup-plyis of concern in many environments due to its role ineutrophication[1].Phosphorus enters rivers from diffusecatchment sources(particularly agriculture)and point(effluent)sources.However,river systems have an im-portant internal capacity to remove or release phosphorusfrom/to the water column and to trans-form phosphorusbetween organic,inorganic,particulate and dissolvedforms.River bed sediments can...

  9. Phosphorus flows and balances of the European Union Member States.

    Science.gov (United States)

    van Dijk, Kimo C; Lesschen, Jan Peter; Oenema, Oene

    2016-01-15

    Global society faces serious "phosphorus challenges" given the scarcity, essentiality, unequal global distribution and, at the same time, regional excess of phosphorus (P). Phosphorus flow studies can be used to analyze these challenges, providing insight into how society (re)uses and loses phosphorus, identifying potential solutions. Phosphorus flows were analyzed in detail for EU-27 and its Member States. To quantify food system and non-food flows, country specific data and historical context were considered. The sectors covered were crop production (CP), animal production (AP), food processing (FP), non-food production (NF) and consumption (HC). The results show that the EU-27 imported 2392 Gg P in 2005, half of which accumulated in agricultural soils (924 Gg) and half was lost as waste (1217 Gg). Net accumulation was 4.9 kg P/ha/year ranging between +23.2 (Belgium) and -2.8 (Slovakia). From the system losses, 54% was lost from HC in diverse waste flows and 28% from FP, mainly through incinerated slaughter residues. The largest HC losses (655 Gg) were wastewater (55%), food waste (27%), and pet excreta (11%). Phosphorus recycling rates were 73% in AP, 29% in FP, 21% in HC and ~0% in NF. The phosphorus use efficiencies showed that, relative to sector input, about 70% was taken up by crops (CP), 24% was retained in animals (AP), 52% was contained in food products (FP), 76% was stored in non-food materials (NF), and 21% was recycled (HC). Although wide-ranging variation between countries, generally phosphorus use in EU-27 was characterized by relatively (1) large dependency on (primary) imports, (2) long-term accumulation in agricultural soils, especially in west European countries, (3) leaky losses throughout entire society, especially emissions to the environment and sequestered waste, (4) little recycling with the exception of manure, and (5) low use efficiencies, because of aforementioned issues, providing ample opportunities for improvement. PMID:26421756

  10. Present status of phosphorus removal technology and its future prospect

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kazuaki

    1988-10-10

    This report outlines the special features of two representative processes of the technology for phosphorus removal from municipal sewage: a physical and chemical method and a biological method. In Japan, coagulating precipitation is carried out using aluminum sulphate or polyaluminum chloride but it is pointed out that this method increases the developed amount of sludge and drops the concentration and dehydration of sludge. Recently, crystallization dephosphorization technology is drawing much attention. This technology precipitates phosphorus as hydroxyapatite using phosphorus ore and bone black as crystal druse under the condition of the addition of lime. For biological dephosphorization, a phostrip method and an anaerobic-aerobic method are being developed. According to the estimation in Japan, it is possible to lower the concentration of total phosphorus in municipal sewage from 5mg*1/sup /minus/1/ to less than 1.0mg*1/sup /minus/1/ by this anaerobic-aerobic method. It is desirable that in the future technical features of the physical and chemical phosphorus removal method and the biological phosphorus removal method will be comparatively studied and a most effective and economic method of preventing eutrophication will be developed and selected. 6 references, 3 figures, 1 table.

  11. Phosphorus and nitrogen regulate arbuscular mycorrhizal symbiosis in Petunia hybrida.

    Directory of Open Access Journals (Sweden)

    Eva Nouri

    Full Text Available Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis, the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi.

  12. Global phosphorus scarcity: identifying synergies for a sustainable future.

    Science.gov (United States)

    Neset, Tina-Simone S; Cordell, Dana

    2012-01-15

    Global food production is dependent on constant inputs of phosphorus. In the current system this phosphorus is not predominantly derived from organic recycled waste, but to a large degree from phosphate-rock based mineral fertilisers. However, phosphate rock is a finite resource that cannot be manufactured. Our dependency therefore needs to be addressed from a sustainability perspective in order to ensure global food supplies for a growing global population. The situation is made more urgent by predictions that, for example, the consumption of resource intensive foods and the demand for biomass energy will increase. The scientific and societal debate has so far been focussed on the exact timing of peak phosphorus and on when the total depletion of the global reserves will occur. Even though the timing of these events is important, all dimensions of phosphorus scarcity need to be addressed in a manner which acknowledges linkages to other sustainable development challenges and which takes into consideration the synergies between different sustainability measures. Many sustainable phosphorus measures have positive impacts on other challenges; for example, shifting global diets to more plant-based foods would not only reduce global phosphorus consumption, but also reduce greenhouse gas emissions, reduce nitrogen fertiliser demand and reduce water consumption. PMID:21969145

  13. Changes in water quality of the River Frome (UK) from 1965 to 2009: Is phosphorus mitigation finally working?

    Energy Technology Data Exchange (ETDEWEB)

    Bowes, M.J., E-mail: mibo@ceh.ac.uk [Centre for Ecology and Hydrology, Maclean Building, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB (United Kingdom); Smith, J.T. [School of Earth and Environmental Sciences, Burnaby Building, University of Portsmouth, Portsmouth PO1 3QL (United Kingdom); Neal, C. [Centre for Ecology and Hydrology, Maclean Building, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB (United Kingdom); Leach, D.V. [formally Centre for Ecology and Hydrology, Winfrith Technology Centre, Dorchester, Dorset, DT2 8ZD (United Kingdom); Scarlett, P.M.; Wickham, H.D.; Harman, S.A.; Armstrong, L.K. [Centre for Ecology and Hydrology, Maclean Building, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB (United Kingdom); Davy-Bowker, J. [Freshwater Biological Association, River Laboratory, East Stoke, Wareham, Dorset, BH20 6BB (United Kingdom); Haft, M. [Freshwater Biological Association, Ferry Landing, Far Sawrey, Ambleside, Cumbria, LA22 0LP (United Kingdom); Davies, C.E. [Centre for Ecology and Hydrology, Maclean Building, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB (United Kingdom)

    2011-08-15

    The water quality of the River Frome, Dorset, southern England, was monitored at weekly intervals from 1965 until 2009. Determinands included phosphorus, nitrogen, silicon, potassium, calcium, sodium, magnesium, pH, alkalinity and temperature. Nitrate-N concentrations increased from an annual average of 2.4 mg l{sup -1} in the mid to late 1960s to 6.0 mg l{sup -1} in 2008-2009, but the rate of increase was beginning to slow. Annual soluble reactive phosphorus (SRP) concentrations increased from 101 {mu}g l{sup -1} in the mid 1960s to a maximum of 190 {mu}g l{sup -1} in 1989. In 2002, there was a step reduction in SRP concentration (average = 88 {mu}g l{sup -1} in 2002-2005), with further improvement in 2007-2009 (average = 49 {mu}g l{sup -1}), due to the introduction of phosphorus stripping at sewage treatment works. Phosphorus and nitrate concentrations showed clear annual cycles, related to the timing of inputs from the catchment, and within-stream bioaccumulation and release. Annual depressions in silicon concentration each spring (due to diatom proliferation) reached a maximum between 1980 and 1991, (the period of maximum SRP concentration) indicating that algal biomass had increased within the river. The timing of these silicon depressions was closely related to temperature. Excess carbon dioxide partial pressures (EpCO{sub 2}) of 60 times atmospheric CO{sub 2} were also observed through the winter periods from 1980 to 1992, when phosphorus concentration was greatest, indicating very high respiration rates due to microbial decomposition of this enhanced biomass. Declining phosphorus concentrations since 2002 reduced productivity and algal biomass in the summer, and EpCO{sub 2} through the winter, indicating that sewage treatment improvements had improved riverine ecology. Algal blooms were limited by phosphorus, rather than silicon concentration. The value of long-term water quality data sets is discussed. The data from this monitoring programme are made

  14. Phosphorus Mobilization from Manure-Amended and Unamended Alkaline Soils to Overlying Water during Simulated Flooding.

    Science.gov (United States)

    Amarawansha, E A G S; Kumaragamage, D; Flaten, D; Zvomuya, F; Tenuta, M

    2015-07-01

    Anaerobic soil conditions resulting from flooding often enhance release of phosphorus (P) to overlying water. Enhanced P release is well documented for flooded acidic soils; however, there is little information for flooded alkaline soils. We examined the effect of flooding and anaerobic conditions on P mobilization using 12 alkaline soils from Manitoba that were either unamended or amended with solid cattle manure. Pore water and floodwater were analyzed over 8 wk of simulated flooding for dissolved reactive P (DRP), Ca, Mg, Fe, and Mn. As expected, manured soils had significantly greater pore and floodwater DRP concentrations than unamended. Flooding increased pore water DRP concentrations significantly in all soils and treatments except one manured clay in which concentrations increased initially and then decreased. Floodwater DRP concentrations increased significantly by two- to 15-fold in 10 soils regardless of amendment treatment but remained relatively stable in the two soils with greatest clay content. Phosphorus release at the onset of flooding was associated with the release of Ca, Mg, and Mn, suggesting that P release may be controlled by the dissolution of Mg and Ca phosphates and reductive dissolution of Mn phosphates. Thereafter, P release was associated with release of Fe, suggesting the reductive dissolution of Fe phosphates. Differences in pore water and floodwater DRP concentrations among soils and amendment treatments and the high variability in P mobilization from pore water to floodwater among soils indicate the need to further investigate chemical reactions responsible for P release and mobility under anaerobic conditions.

  15. Recycling phosphorus by fast pyrolysis of pig manure: concentration and extraction of phosphorus combined with formation of value-added pyrolysis products

    NARCIS (Netherlands)

    Azuara, M.; Kersten, S.R.A.; Kootstra, A.M.J.

    2013-01-01

    In order to recycle phosphorus from the livestock chain back to the land, fast pyrolysis of concentrated pig manure at different temperatures (400 °C, 500 °C, 600 °C), was undertaken to concentrate the phosphorus in the char fraction for recovery. Results show that 92%–97% of the phosphorus present

  16. Impacts of anthropic pressures on soil phosphorus availability, concentration, and phosphorus forms in sediments in a Southern Brazilian watershed

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, Joao Batista Rossetto; Rheinheimer dos Santos, Danilo; Goncalves, Celso Santos; Copetti, Andre Carlos Cruz [Dept. de Solos, Univ. Federal de Santa Maria, Centro de Ciencias Rurais, Santa Maria, RS (Brazil); Bortoluzzi, Edson Campanhola [Faculdade de Agronomia e Medicina Veterinaria da Univ. de Passo Fundo, RS (Brazil); Tessier, Daniel [Inst. National de la Recherche Agronomique, Versailles (France)

    2010-04-15

    Purpose: The transfer of soil sediments and phosphorus from terrestrial to aquatic systems is a common process in agricultural lands. The aims of this paper are to quantify the soil phosphorus availability and to characterize phosphorus forms in soil sediments as contaminant agents of waters as a function of anthropic pressures. Materials and methods On three subwatersheds with different anthropic pressure, water and sediment samples were collected automatically in upstream and downstream discharge points in six rainfall events during the tobacco growing season. Phosphorus desorption capacity from soil sediments was estimated by successive extractions with anion exchange resins. First-order kinetic models were adjusted to desorption curves for estimating potentially bioavailable particulate phosphorus, desorption rate constant, and bioavailable particulate phosphorus. Results and discussion The amount of bioavailable particulate phosphorus was directly correlated with the iron oxide content. The value of desorption rate constant was directly related with the total organic carbon and inversely with the iron oxide contents. Phosphate ions were released to solution, on average, twice as rapidly from sediments collected in subwatersheds with low anthropic activity than from those ones of highly anthropic subwatersheds. Anthropic pressure on watershed can engender high sediment discharge, but these solid particles seem to present low phosphorus-releasing capacity to water during transport due to the evidenced high affinity between phosphorus and iron oxide from sediments. Conclusions Anthropic pressure was related with sediment concentration and phosphorus release to aquatic systems. While natural vegetation along streams plays a role on soil and water depuration, it is unable to eliminate the phosphorus inputs intrinsic to the agricultural-intensive systems. Recommendations and perspectives The contamination of water in watershed by phosphates is facilitated by the

  17. Effect of phosphorus and organic matter on soil-plant phosphorus relationships in spinach

    Directory of Open Access Journals (Sweden)

    M. Zahedifar

    2011-03-01

    Full Text Available To determine the effect of application of phosphorus (P and organic matter on soil-plant P relationship at different growth stages of spinach, an experiment was conducted at greenhouse conditions. Treatments consisted of two levels of organic matter (0 and 2% of sheep manure and three levels of P as Ca(H2PO42 (0, 20 and 60 mg P kg-1soil. Soil and plant samples were collected at five growth stages (the first sampling was in the fourth week after emergence, and the other samplings were each one week after the first sampling. The results showed that crop yield increased with the increase of soil P at all growth stages, whereas it had no significant effect on plant P content. In the 4th week of growth, plant P increased with an increase of soil P, and it remained relatively unchanged in the 5th week. But it decreased significantly in the 6th to 8th week. Concentration of plant nutrients depends not only on soil nutrients concentration but also on plant age and availability of other nutrients. In some stages of the plant growth, the growth rate might be too fast such that total uptake of the nutrients is not enough to maintain the necessary concentration. Plants required adequate P at early growth stages for optimum growth. Phosphorus uptake was increased with plant growth in all samples. Soil P content was higher in all organic matter treatments (especially in the 6th week after emergence. Phosphorus uptake in samples with organic matter, and no addition of P, was more than the samples which received P. This might be due to mineralization of organic P added to the soil.

  18. Synthesis of vanadium-phosphorus oxide systems by joint chemisorption of phosphorus and vanadium oxychlorides on silica surface

    International Nuclear Information System (INIS)

    A new method of synthesis on silica of multilayer vanadium-phosphorus oxide systems containing vanadium in oxidation state (+4), which consists in joint chemisorption of phosphorus and vanadium oxychlorides, hydrolysis of surface chlorine-containing compounds by water steam and vanadium reduction by ammonia vapors, was suggested. The samples prepared were characterized by the method of ESR, IR spectroscopy and electron spectroscopy of diffuse reflection

  19. Performance Analysis of uniaxially strained Monolayer Black Phosphorus and Blue Phosphorus n-MOSFET and p-MOSFET

    OpenAIRE

    Banerjee, L.; Mukhopadhyay, A.; Sengupta, A.; Rahaman, H.

    2016-01-01

    In this work, we present a computational study on the possibility of strain engineering in monolayer Black Phosphorus (black P) and Blue Phosphorus (blue P) based MOSFETs. The material properties like band structure, carrier effective masses, carrier densities at band extrema are evaluated using Generalized Gradient Approximation (GGA) in Density Functional Theory (DFT).Thereafter self-consistent Non-Equilibrium Greens Function (NEGF) simulations are carried out to study the device performanc...

  20. Metal free earth abundant elemental red phosphorus: a new class of visible light photocatalyst and photoelectrode materials.

    Science.gov (United States)

    Ansari, Sajid Ali; Ansari, Mohammad Shahnawaze; Cho, Moo Hwan

    2016-02-01

    Developing a high-performance photocatalyst and a photoelectrode with enhanced visible light harvesting properties is essential for practical visible light photocatalytic applications. Noble metal-free, highly visible light-active, elemental red phosphorus (RP) was prepared by a facile mechanical ball milling method, which is a reproducible, low cost and controllable synthesis process. The synthesis used inexpensive and abundant raw materials because most RP hybrids are based on expensive noble-metals. The novel milled RP showed significantly enhanced photocatalytic and photoelectrochemical performances with a lower charge transfer resistance compared to commercial RP under wide visible photoirradiation, making it a feasible alternative for photocatalytic applications. PMID:26765211

  1. Effect of supplemented fungal phytase on performance and phosphorus availability by phosphorus-depleted juvenile rainbow trout (Oncorhynchus mykiss), and on the magnitude and composition of phosphorus waste output

    DEFF Research Database (Denmark)

    Dalsgaard, Anne Johanne Tang; Schøn Ekmann, K.; Pedersen, Per Bovbjerg;

    2009-01-01

    The effect of a supplemental fungal phytase on performance and phosphorus availability by juvenile rainbow trout fed diets with a high inclusion of plant based protein and on the magnitude and composition of the waste phosphorus production was tested in a 2 × 3 factorial design at a temperature...... of plant-derived protein. Conversely, the results demonstrated that fungal phytase should not be supplemented to diets in which the available phosphorus level already meets the requirement of the fish, as this will lead to a significant increase in the dissolved/suspended phosphorus waste output....... of 11 °C. Two factors comprised of two dietary fungal phytase levels (0 or 1400 U kg− 1 feed− 1), and three dietary total phosphorus levels (0.89, 0.97 or 1.12%). All fish were acclimated to the lowest total phosphorus diet for 16 days, which included 0.29% phytate-phosphorus and no supplemental fungal...

  2. Effect of phosphorus on vacancy-type defect behaviour in electron-irradiated Ni studied by positron annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Druzhkov, A.P., E-mail: druzhkov@imp.uran.ru; Danilov, S.E.; Perminov, D.A.; Arbuzov, V.L.

    2015-02-15

    Very dilute Ni–P system (containing 50–240 appm phosphorus) irradiated by 5 MeV electrons at various temperatures (270–543 K) was studied by positron annihilation spectroscopy (PAS) and the electrical resistivity measurements. Under irradiation at 270 K (below stage III in Ni), the accumulation of the monovacancies in the Ni–P system is 1.5–2.0 times greater than that in pure Ni irradiated in the same conditions. This fact attests to the strong interaction between P atoms and self-interstitial atoms (SIAs). As a result of the non-mobile SIA–P complexes formation, the mutual recombination of point defects is suppressed and the vacancy accumulation is, respectively, enhanced. During post-irradiation annealing, the vacancy migration induces the transport process of the phosphorus atoms and leads to the formation of the vacancy clusters decorated with P atoms. The annealing behaviour of the defect structures in Ni–P systems after irradiation at enhanced temperatures was also studied. The influence of phosphorus on the formation and further evolution of the vacancy aggregates decrease with increasing of the irradiation temperature.

  3. AN OVERVIEW ON ROLE OF PHOSPHORUS AND WATER DEFICITS ON GROWTH, YIELD AND QUALITY OF GROUNDNUT (ARACHIS HYPOGAEA L.

    Directory of Open Access Journals (Sweden)

    S. Hemalatha

    2013-08-01

    Full Text Available Fertilizer application in crop plants normally result in enhanced crop yields up to certain levels. Each of these major and minor nutrients have specific role in producing growth and yield enhancement in agricultural crops. However, the exact time and dose of fertilizer application in the given crop schedule is also of paramount importance for successfully exploiting the crop’s potentiality in terms of yield. Groundnut is an important oilseed crop in the tropics and semi-arid tropics. Yield and often quality of oil in groundnut is sizeably dependent on proper application of different nutrients that have a direct say on these attributes. Phosphorus application in groundnut has tremendous impact on growth and development in groundnut. Further, the effect of phosphorus on yield and yield attributes is also well established. Another important factor determining crop growth and yields in groundnut is water. During periods of unpredictable water shortages, within season adjustments of water scheduling must be made in relation to the difference in the yield sensitivity to water deficits on groundnut and its individual growth periods. Thus management of limited water supplies for increased crop production requires studies on water production function of groundnut. This paper reviews information on phosphorus fertilization studies in groundnut and also in identifying moisture sensitive periods in groundnut for limited water management.

  4. The Behavior of Phosphorus During Reduction and Carburization of High-Phosphorus Oolitic Hematite with H2 and CH4

    Science.gov (United States)

    Wang, Henghui; Li, Guangqiang; Yang, Jian; Ma, Jianghua; Khan, Babar Shahzad

    2016-06-01

    High-phosphorus oolitic hematite has not been widely utilized due to high content of phosphorus. Ca3(PO4)2 is the main component containing phosphorus in high-phosphorus oolitic hematite. In the present work, the thermodynamics was studied for Ca3(PO4)2 reduction by H2 gas and then carburization by CH4 gas. The results show that phosphorous in Ca3(PO4)2 cannot be reduced from gangue during the reduction of hematite and the formation of iron carbide at the temperature from 923 K to 1073 K (650 °C to 800 °C), in H2 and CH4 atmosphere. Reduction and carburization experiments were carried out. And phosphorus in reduced and carburized specimens was analyzed by EDS and wet chemical method. The results confirmed that phosphorous cannot be reduced during the preparation of iron carbide from this iron ore. So the metallic iron or iron carbide can be prepared without the reduction of phosphorous at relatively low temperature, which can be a new route of utilizing high-phosphorus oolitic hematite. After fine milling-magnetic separation, the 99.47 pct of Fe3C-containing material was recovered, but the dephosphorization rate reached to 19.37 pct only.

  5. Catalytic activity of phosphorus and steam modified HZSM-5 and the theoretical selection of phosphorus grafting model

    Institute of Scientific and Technical Information of China (English)

    Renqing Lü; Zuogang Cao; Xinhai Liu

    2008-01-01

    The modification of HZSM-5 zeolite with phosphorus and steam has been studied. Results show that 1% phospho-rus and steam modified HZSM-5 has the highest catalytic activity for n-heptane. Physicochemical and catalytic properties of 1% phosphorus and steam modified HZSM-5 zeolites have been investigated. The X-ray diffraction (XRD) results exhibit that there is considerable variation in the relative intensity of the individual diffraction peaks. The acidity of the samples decreases with an increase in the steaming temperature, which is determined by the IR of adsorbed pyridine and temperature programmed desorption (TPD) of ammonia. The oxidation state of phosphorus shown by XPS is +5, and a model for surface structure modification is proposed. The nitrogen adsorption isotherm for all samples is a combination of type Ⅰ and type Ⅳ, all hysteresis loops resemble the H4-type. The density functional and cluster model methods have been invoked to select the phosphorus grafting model, and it was found that the phosphorus grafting model were more probable in the form of the terminal oxygen coordinating with aluminum.

  6. Dynamics in phosphorus retention in wetlands upstream of Delavan Lake, Wisconsin

    Science.gov (United States)

    Robertson, Dale M.; Elder, John F.; Goddard, Gerald L.; James, William F.

    2009-01-01

    A phosphorus budget was constructed for Delavan Lake Inlet, a perennial riverine wetland with submersed and floating aquatic vegetation in southeastern Wisconsin, to better understand the phosphorus dynamics in natural wetlands and the role of wetlands in lake-rehabilitation efforts. During the growing season, the inlet served as a net source of phosphorus, primarily due to the release of phosphorus from the sediments. More phosphorus was released from the sediments of the inlet (600 kg) than was input from the upstream watershed (460 kg). This release was caused by high pH associated with high photosynthetic activity. During the remainder of the year, the inlet served as a net sink for phosphorus, retaining 6% of die phosphorus input from the watershed. Over the entire year, this wetland was a net source of over 500 kg of phosphorus to downstream Delavan Lake. A constructed riverine wetland upstream of Delavan Lake Inlet demonstrated a similar periodic release of phosphorus. However, in this case, the summer release of phosphorus was less than that trapped during the remainder of the year. The constructed wetland served as a net sink for approximately 20% of the input phosphorus on an annual time scale. The role of existing and constructed wetlands as phosphorus traps is complex. Wetlands can act as a source or a sink for phosphorus depending on the ambient conditions in die wetland. Howa wetland fits into a rehabilitation plan depends upon its net retention efficiency and the importance of the periodic releases of phosphorus to downstream waters.

  7. Black phosphorus nanoelectromechanical resonators vibrating at very high frequencies

    Science.gov (United States)

    Wang, Zenghui; Jia, Hao; Zheng, Xuqian; Yang, Rui; Wang, Zefang; Ye, G. J.; Chen, X. H.; Shan, Jie; Feng, Philip X.-L.

    2014-12-01

    We report on the experimental demonstration of a new type of nanoelectromechanical resonator based on black phosphorus crystals. Facilitated by a highly efficient dry transfer technique, crystalline black phosphorus flakes are harnessed to enable drumhead resonators vibrating at high and very high frequencies (HF and VHF bands, up to ~100 MHz). We investigate the resonant vibrational responses from the black phosphorus crystals by devising both electrical and optical excitation schemes, in addition to measuring the undriven thermomechanical motions in these suspended nanostructures. Flakes with thicknesses from ~200 nm down to ~20 nm clearly exhibit elastic characteristics transitioning from the plate to the membrane regime. Both frequency- and time-domain measurements of the nanomechanical resonances show that very thin black phosphorus crystals hold interesting potential for moveable and vibratory devices and for semiconductor transducers where high-speed mechanical motions could be coupled to the attractive electronic and optoelectronic properties of black phosphorus.We report on the experimental demonstration of a new type of nanoelectromechanical resonator based on black phosphorus crystals. Facilitated by a highly efficient dry transfer technique, crystalline black phosphorus flakes are harnessed to enable drumhead resonators vibrating at high and very high frequencies (HF and VHF bands, up to ~100 MHz). We investigate the resonant vibrational responses from the black phosphorus crystals by devising both electrical and optical excitation schemes, in addition to measuring the undriven thermomechanical motions in these suspended nanostructures. Flakes with thicknesses from ~200 nm down to ~20 nm clearly exhibit elastic characteristics transitioning from the plate to the membrane regime. Both frequency- and time-domain measurements of the nanomechanical resonances show that very thin black phosphorus crystals hold interesting potential for moveable and vibratory

  8. Expert systems guide biological phosphorus removal

    Energy Technology Data Exchange (ETDEWEB)

    Krichten, D.J.; Wilson, K.D.; Tracy, K.D. (Air Products and Chemicals, Inc., Allentown, PA (United States))

    1991-10-01

    There is a large body of knowledge regarding optimum control strategies for new secondary wastewater treatment technology using an anaerobic selector to provide biological phosphorus removal. However, because the selector technology is new and the concepts differ somewhat from those used in conventional activated sludge wastewater treatment, a method of communicating this knowledge to plant operators is needed. Traditional methods such as classroom training and operating manuals are of limited effectiveness. The commonplace availability and low cost of the personal computer (PC) makes it practical to use a computer program to communicate the type of information required to control a wastewater treatment plant. Knowledge-based systems technology, commonly referred to as expert systems (ES) technology, is easy to use, provides useful information regarding a consistent control strategy, relieves the anxiety associated with learning a new process,' and provides instruction for inexperienced personnel. ES technology does not require special formatted input and is therefore easily accessible. All information required by the program is readily available through routine laboratory analysis, common plant instrumentation, or direct user observation. The program was designed for all levels of computer users and will run on all IBM-compatible or Apple MacIntosh systems.

  9. Phosphorus requirements for containerized Pterocarpus indicus seedlings

    Institute of Scientific and Technical Information of China (English)

    Eng Hai Lok; Bernard Dell

    2015-01-01

    Pterocarpus indicus Willd is a tropical woody legume that holds promise for plantation forestry. Two glasshouse experiments were undertaken on two soil types to determine the phosphorus (P) concentration ranges in the foliage of P-stressed and healthy plants, and to define cri-tical P concentrations for the diagnosis of deficiency and toxicity. There was a narrow range in rates of P fertilizer, supplied as Ca(H2PO4)2?H20, between deficiency and toxicity compared to other tree species. The relationship between shoot yield and P concentration in the youngest fully expanded leaf enabled critical P concentrations for the diagnosis of deficiency (0.17%) and toxicity (0.41%) to be determined at 90% maximum yield from linear re-gressions fitted to the data. The foliar P concentration ranges for deficiency and toxicity were similar to other nitrogen-fixing trees. The defined P concentration ranges and the critical P concentrations for the diagnosis of P deficiency and P toxicity should be useful for monitoring the P status of nursery stock and the health of young seedlings after out-planting.

  10. The role of phosphorus in eutrophication

    Directory of Open Access Journals (Sweden)

    Bogdanović Darinka M.

    2006-01-01

    Full Text Available Eutrophication is an increase in the biological productivity of water basins resulting from the accumulation of biogenic elements under the influence of anthropogenic factors. Natural eutrophication is a slow and inevitable process. Artifical eutrophica-tion is caused by human activity and it can be very rapid, especially in technologically developed countries. Eutrophication does not represent a mere change of water but a change in the metabolism of the entire ecosystem and hence a change of the ecosystem itself. In Serbia and Montenegro, all factors are present that promote eutrophication in both still (especially in lowland areas and running waters. This paper deals with the results of eutrophication monitoring and prognostication for the DTD canal network and major rivers and lakes in Serbia, including a special review of the trophic status of lakes in the country's main lowland region, the Vojvodina Province. As phosphorus concentration is an important factor in the process of eutrophication of a body of water, the study has devoted particular attention to the control of this element.

  11. Phosphorus in lacustrine groundwater discharge drives eutrophication

    Science.gov (United States)

    Meinikmann, Karin; Hupfer, Michael; Lewandowski, Jörg

    2016-04-01

    Lake eutrophication has long been mainly associated with phosphorus (P) inputs from overland flow. Our work gives evidence that also groundwater can carry significant loads of dissolved P. We quantified P loads from groundwater to Lake Arendsee using near-shore measurements of P concentrations at a high spatial resolution and volume fluxes of lacustrine groundwater discharge (LGD) derived from a previous study. Results show that LGD accounts for more than 50% of the overall external P load, thus fueling the eutrophication of the lake. Several different approaches of groundwater sampling (groundwater observation wells, temporary piezometers, and domestic wells) reveal a broad spatial heterogeneity of P concentrations in the subsurface catchment of the lake. The highest P concentrations (above 4 mg/L) were found below a settled area along the southern lake shore. Contrary to expectations, other parameters (dissolved iron, ammonium, etc.) were not correlated with P, indicating that natural processes are superimposed by heavy contaminations. Both the intensity of the contamination and its proximity to the lake inhibit nutrient retention within vadose zone and aquifer and allow significant P loads to be discharged into the lake.

  12. Bacteria as transporters of phosphorus through soil

    DEFF Research Database (Denmark)

    Glæsner, N.; Bælum, Jacob; Jacobsen, C. S.;

    2016-01-01

    The transport of phosphorus (P) from agricultural land has led to the eutrophication of surface waters worldwide, especially in areas with intensive animal production. In this research, we investigated the role of bacteria in the leaching of P through three agricultural soils with different......RNA genes cell−1. Leaching of bacteria was in the range of 2.5–4.5 × 105 cells ml−1 prior to application of slurry to the three soil textures. After slurry application, leaching increased to 1.1 × 106 cells ml−1 in the loamy sand, 4.9 × 106 cells ml−1 in the sandy loam and 5.0 × 106 cells ml−1 in the loam....... Based on the reported P content of soil bacteria, 0.3–1.8% of the total P leached was present in the bacterial biomass when no slurry was applied, whereas slurry application increased the leaching of P from the bacterial biomass to 3−7.9% of total P leached. Bacterial leaching was related...

  13. The role of diet in phosphorus demand

    Science.gov (United States)

    Metson, Geneviève S.; Bennett, Elena M.; Elser, James J.

    2012-12-01

    Over the past 50 years, there have been major changes in human diets, including a global average increase in meat consumption and total calorie intake. We quantified how changes in annual per capita national average diets affected requirements for mined P between 1961 and 2007, starting with the per capita availability of a food crop or animal product and then determining the P needed to grow the product. The global per capita P footprint increased 38% over the 46 yr time period, but there was considerable variability among countries. Phosphorus footprints varied between 0.35 kg P capita-1 yr-1 (DPR Congo, 2007) and 7.64 kg P capita-1 yr-1 (Luxembourg, 2007). Temporal trends also differed among countries; for example, while China’s P footprint increased almost 400% between 1961 and 2007, the footprints of other countries, such as Canada, decreased. Meat consumption was the most important factor affecting P footprints; it accounted for 72% of the global average P footprint. Our results show that dietary shifts are an important component of the human amplification of the global P cycle. These dietary trends present an important challenge for sustainable P management.

  14. 不同固磷方式对巢湖沉积物磷吸附行为的影响%EFFECTS OF DIFFERENT PHOSPHORUS IMMOBILIZATION WAYS ON PHOSPHORUS SORPTION BEHAVIORS IN SEDIMENT OF LAKE CHAOHU

    Institute of Scientific and Technical Information of China (English)

    刘云兵; 孙爱华; 曹秀云; 宋春雷; 周易勇

    2011-01-01

    Internal phosphorus loading in sediment will exert negative effects on restoration of eutrophic lakes, whose control is dependent on the effective enhancement of phosphorus sorption on sediments, but relevant works are scare. In this study, the sediments from the seriously polluted areas in a Chinese eutrophic lake (Lake Chaohu) were obtained, and the effects of the routine technologies such as dosing salts of calcium, iron, aluminium and aeration, on sediments phosphorus sorption behavior and interstitial water soluble reactive phosphorus (SRP) concentration were compared with the application of calcium salt, no significant changes in phosphorus sorption maximum and the bonding energy were observed, together with the slight decrease in SRP concentration in interstitial water and zero equilibrium phosphorus concentration (EPC0) in sediment; furthermore, the application of salts of iron and aluminium not only significant enhanced phosphorus sorption maximum and the bonding energy, but also decreased SRP concentration in interstitial water and EPC0 in sediments, leading to a stronger ability to adsorb phosphate from aqueous phase into sediment.With the lowest dosage, iron salt could reduce sediment EPC0 more effective relative to aluminium salt; on the other hand, aeration had no significant effects on phosphorus sorption maximum and the bonding energy, and what is worse, it substantially gave rise to SRP concentration in interstitial water and sediment EPC0 value, thereby increasing risk of phosphorus release. Overall, iron salt application with optimal dosage can be taken as a suitable technology for sediment remediation of eutrophic lakes, while the benthic aeration must be cautiously used.%内源磷负荷将严重阻碍富营养化湖泊的恢复,其控制技术的关键在于有效增强沉积物吸附磷的能力,而相关研究相对较少.研究以典型富营养化湖泊(巢湖)严重污染区域的沉积物为实验对象,系统比较了

  15. Black Phosphorus Flexible Thin Film Transistors at Gighertz Frequencies.

    Science.gov (United States)

    Zhu, Weinan; Park, Saungeun; Yogeesh, Maruthi N; McNicholas, Kyle M; Bank, Seth R; Akinwande, Deji

    2016-04-13

    Black phosphorus (BP) has attracted rapidly growing attention for high speed and low power nanoelectronics owing to its compelling combination of tunable bandgap (0.3 to 2 eV) and high carrier mobility (up to ∼1000 cm(2)/V·s) at room temperature. In this work, we report the first radio frequency (RF) flexible top-gated (TG) BP thin-film transistors on highly bendable polyimide substrate for GHz nanoelectronic applications. Enhanced p-type charge transport with low-field mobility ∼233 cm(2)/V·s and current density of ∼100 μA/μm at VDS = -2 V were obtained from flexible BP transistor at a channel length L = 0.5 μm. Importantly, with optimized dielectric coating for air-stability during microfabrication, flexible BP RF transistors afforded intrinsic maximum oscillation frequency fMAX ∼ 14.5 GHz and unity current gain cutoff frequency fT ∼ 17.5 GHz at a channel length of 0.5 μm. Notably, the experimental fT achieved here is at least 45% higher than prior results on rigid substrate, which is attributed to the improved air-stability of fabricated BP devices. In addition, the high-frequency performance was investigated through mechanical bending test up to ∼1.5% tensile strain, which is ultimately limited by the inorganic dielectric film rather than the 2D material. Comparison of BP RF devices to other 2D semiconductors clearly indicates that BP offers the highest saturation velocity, an important metric for high-speed and RF flexible nanosystems. PMID:26977902

  16. Aerobic granular sludge for simultaneous accumulation of mineral phosphorus and removal of nitrogen via nitrite in wastewater.

    Science.gov (United States)

    Li, Yongmei; Zou, Jinte; Zhang, Lili; Sun, Jing

    2014-02-01

    Lab-scale experiments were conducted to investigate the aerobic granular sludge process for simultaneous phosphorus (P) accumulation by chemical precipitation and biological nitrogen removal via nitrite. The P-rich granules were successfully incubated in a sequencing batch reactor, in which simultaneous nitrification-denitrification occurred via nitrite. The average diameter of the P-rich granules was 2.47 mm and the P content in granules was much higher than that in other granular systems with enhanced biological phosphorus removal process. Filamentous bacteria (genus Thiothrix) in the granules and the long sludge retention time (30 d) of the granular system played a crucial role in accumulation of precipitated phosphate. X-ray diffraction analysis, scanning electron microscopy coupled with energy dispersive X-ray and the experimental design using response surface methodology confirmed that the main mineral patterns in P-rich granules were Ca-Mg phosphate and whitlockite. PMID:24388958

  17. THE INFLUENCE OF PHOSPHORUS SLAG ADDITION ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF METAKAOLIN-BASED GEOPOLYMER PASTES

    Directory of Open Access Journals (Sweden)

    M. A. SOLEIMANI

    2013-03-01

    Full Text Available In this study, metakaolin plus different weight percent of phosphorus slag (10-100 wt. % were used in preparation of geopolymer. The compressive strength, phase analysis and microstructure changes were compared with a metakaolin based geopolymer control sample. Results showed that the substitution of slag up to 40 wt. % instead of metakaolin increase the 28 days compressive strength (14.5 % compared with control sample. This enhancement of strength is related to coexistence of geopolymeric gel and C‒S‒H gel or C‒A‒S‒H phase by XRD and FTIR study. In slag containing geopolymer samples some microcracks were observed at microstructure that established by volume change during formation of new phase or mismatching of unreacted particle with geopolymeric gel. These microcrack can dominate at high content of slag (above 40 wt. % substitution and decrease the strength of samples. These results show that it is possible to produce geopolymer cement from waste phosphorus slages.

  18. Remoção de fósforo de efluentes da parboilização de arroz por absorção biológica estimulada em reator em batelada sequencial (RBS Rice parboilization wastewater phosphorus removal by enhanced biological assimilation in sequencing batch reactor (SBR

    Directory of Open Access Journals (Sweden)

    Osvaldo Luís Vieira Faria

    2006-06-01

    Full Text Available O efluente do arroz parboilizado contém altas concentrações de fósforo. Um reator em batelada seqüencial (RBS alimentado com efluente de reator UASB, operou com três fases anaeróbias e aeróbias e tempo de detenção de sólidos (TDS de 25 d, 15 d, 10 d e 5d e tempo de reação (tR de 1 d, 2 d e 3 d com e sem a adição de ácido acético (HAc. O reator operou com o efluente do equalizador em duas fases tratando com TDS de cinco dias. A eficiência foi calculada pela relação entre a massa de fósforo suspenso descartada e a massa total alimentada. O maior potencial de remoção de 46,14 mg ocorreu operando-se com uma fase anaeróbia e uma aeróbia com adição de HAc. O tR de um dia tem a maior possibilidade de aumento da eficiência pelo incremento do descarte de biomassa. A operação com TDS menores obtém as maiores eficiências de remoção. A capacidade de remoção é melhor utilizada com TDS de cinco dias. A maior eficiência (E=17,82% foi obtida tratando o efluente do reator UASB com TDS de cinco dias, com duas fases, sem a adição HAc.The parboiled rice effluent has high phosphorus concentration. A sequential batch reactor (SBR was fed with a UASB reactor effluent and operated with three anaerobic and aerobic phases and solids retention time (SRT of 25 d, 15 d, 10 d and 5 d, and reaction time (tR of 1 d, 2 d and 3 d, with and without acetic acid (HOAc addition. The reactor operated with 5 d of SRT and two phases treating equalization tank effluent. The removal efficiency was calculated by the relation between phosphorus suspended wasted mass and feed mass. The biggest removal potential, 46.14 mg, was operated with HOAc addition and one anaerobic and aerobic phase. The biggest possibility of efficiency increase by biomass waste was obtained with tR=1 d. The system operating with smaller SRT achieves higher removal efficiencies. The removal capacity is better utilized with five days of SRT. The highest efficiency (E=17.82% was

  19. Optimizing phosphorus diffusion for photovoltaic applications: Peak doping, inactive phosphorus, gettering, and contact formation

    Science.gov (United States)

    Wagner, Hannes; Dastgheib-Shirazi, Amir; Min, Byungsul; Morishige, Ashley E.; Steyer, Michael; Hahn, Giso; del Cañizo, Carlos; Buonassisi, Tonio; Altermatt, Pietro P.

    2016-05-01

    The phosphosilicate glass (PSG), fabricated by tube furnace diffusion using a POCl3 source, is widely used as a dopant source in the manufacturing of crystalline silicon solar cells. Although it has been a widely addressed research topic for a long time, there is still lack of a comprehensive understanding of aspects such as the growth, the chemical composition, possible phosphorus depletion, the resulting in-diffused phosphorus profiles, the gettering behavior in silicon, and finally the metal-contact formation. This paper addresses these different aspects simultaneously to further optimize process conditions for photovoltaic applications. To do so, a wide range of experimental data is used and combined with device and process simulations, leading to a more comprehensive interpretation. The results show that slight changes in the PSG process conditions can produce high-quality emitters. It is predicted that PSG processes at 860 °C for 60 min in combination with an etch-back and laser doping from PSG layer results in high-quality emitters with a peak dopant density Npeak = 8.0 × 1018 cm-3 and a junction depth dj = 0.4 μm, resulting in a sheet resistivity ρsh = 380 Ω/sq and a saturation current-density J0 below 10 fA/cm2. With these properties, the POCl3 process can compete with ion implantation or doped oxide approaches.

  20. Phosphorus fertilization of 'Fuyutoyo' cabbages in phosphorus-rich Eutrustox soil

    Directory of Open Access Journals (Sweden)

    Arthur Bernardes Cecílio Filho

    2013-09-01

    Full Text Available Crop fertilization with P is a practice that constantly needs to be improved because of its high cost, natural reserve constraints, and environmental impact caused by the excessive use of nutrients. Phosphorus rates (0, 120, 240, 360, 480, 600, and 720 kg P2O5 ha-1 in the cultivation of 'Fuyutoyo' cabbage (Brassica oleracea L. var. capitata in a P-rich Eutrustox soil (93 mg P dm-3 in Jaboticabal (21°15'22'' S, 48°15'58" W; 575 m a.s.l., São Paulo, Brazil, were evaluated in an experiment with a randomized complete block design with three replicates. Phosphorus rates influenced plant characteristics and soil P content. Maximum leaf and soil P content was obtained with 720 kg P2O5 ha-1, but maximum values of leaf area, leaf dry mass, cabbage head mass, and productivity were obtained with 420, 310, 430, and 437.5 kg ha-1 P2O5, respectively. Results indicate that even crops grown in a P-rich soil benefit from applying P fertilizer, which has a positive effect on the growth and productivity of the 'Fuyutoyo' cabbage.

  1. Phosphorus depletion in forest soils shapes bacterial communities towards phosphorus recycling systems.

    Science.gov (United States)

    Bergkemper, Fabian; Schöler, Anne; Engel, Marion; Lang, Friederike; Krüger, Jaane; Schloter, Michael; Schulz, Stefanie

    2016-06-01

    Phosphorus (P) is an important macronutrient for all biota on earth but similarly a finite resource. Microorganisms play on both sides of the fence as they effectively mineralize organic and solubilize precipitated forms of soil phosphorus but conversely also take up and immobilize P. Therefore, we analysed the role of microbes in two beech forest soils with high and low P content by direct sequencing of metagenomic deoxyribonucleic acid. For inorganic P solubilization, a significantly higher microbial potential was detected in the P-rich soil. This trait especially referred to Candidatus Solibacter usiatus, likewise one of the dominating species in the data sets. A higher microbial potential for efficient phosphate uptake systems (pstSCAB) was detected in the P-depleted soil. Genes involved in P starvation response regulation (phoB, phoR) were prevalent in both soils. This underlines the importance of effective phosphate (Pho) regulon control for microorganisms to use alternative P sources during phosphate limitation. Predicted genes were primarily harboured by Rhizobiales, Actinomycetales and Acidobacteriales. PMID:26690731

  2. Effect of polyaluminium chloride on phosphorus removal in constructed wetlands treated with swine wastewater.

    Science.gov (United States)

    Reddy, G B; Forbes, Dean A; Hunt, P G; Cyrus, Johnsely S

    2011-01-01

    Total phosphorus (TP) removal in aged constructed wetlands poses a challenge, especially when treated with swine wastewater with high concentrations of phosphorus (P). Our earlier studies with anaerobic lagoon swine wastewater treatment in constructed wetlands showed a decline in P removal (45-22%) with increased years of operation. These particular wetlands have been treated with swine wastewater every year since the first application in 1997. Preliminary lab-scale studies were conducted to evaluate the efficiency of polyaluminium chloride (PAC) in the removal of phosphate-P (PO4-P) from swine wastewater. The experimental objective was to increase the phosphorus treatment efficiency in constructed wetland by adding PAC as a precipitating agent. PAC was added by continuous injection to each wetland system at a rate of 3 L day(-1) (1:5 dilution of concentrated PAC). Swine wastewater was added from an anaerobic lagoon to four constructed wetland cells (11m wide x 40m long) at TP loads of 5.4-6.1 kg ha(-1) day(-1) in two experimental periods, September to November of 2008 and 2009. Treatment efficiency of two wetland systems: marsh-pond-marsh (M-P-M) and continuous marsh (CM) was compared. The wetlands were planted with cattails (Typha latifolia L.) and bulrushes (Scirpus americanus). In 2008, PAC treatment showed an increase of 27.5 and 40.8% of TP removal over control in M-P-M and CM respectively. Similar trend was also observed in the following year. PAC as a flocculant and precipitating agent showed potential to enhance TP removal in constructed wetlands treated with swine wastewater. PMID:22049722

  3. Wood ash as a magnesium source for phosphorus recovery from source-separated urine.

    Science.gov (United States)

    Sakthivel, S Ramesh; Tilley, Elizabeth; Udert, Kai M

    2012-03-01

    Struvite precipitation is a simple technology for phosphorus recovery from source-separated urine. However, production costs can be high if expensive magnesium salts are used as precipitants. Therefore, waste products can be interesting alternatives to industrially-produced magnesium salts. We investigated the technical and financial feasibility of wood ash as a magnesium source in India. In batch experiments with source-separated urine, we could precipitate 99% of the phosphate with a magnesium dosage of 2.7 mol Mg mol P(-1). The availability of the magnesium from the wood ash used in our experiment was only about 50% but this could be increased by burning the wood at temperatures well above 600 °C. Depending on the wood ash used, the precipitate can contain high concentrations of heavy metals. This could be problematic if the precipitate were used as fertilizer depending on the applicable fertilizer regulations. The financial study revealed that wood ash is considerably cheaper than industrially-produced magnesium sources and even cheaper than bittern. However, the solid precipitated with wood ash is not pure struvite. Due to the high calcite and the low phosphorus content (3%), the precipitate would be better used as a phosphorus-enhanced conditioner for acidic soils. The estimated fertilizer value of the precipitate was actually slightly lower than wood ash, because 60% of the potassium dissolved into solution during precipitation and was not present in the final product. From a financial point of view and due to the high heavy metal content, wood ash is not a very suitable precipitant for struvite production. Phosphate precipitation from urine with wood ash can be useful if (1) a strong need for a soil conditioner that also contains phosphate exists, (2) potassium is abundant in the soil and (3) no other cheap precipitant, such as bittern or magnesium oxide, is available. PMID:22297249

  4. Comparative proteome analysis of metabolic changes by low phosphorus stress in two Brassica napus genotypes.

    Science.gov (United States)

    Yao, Yinan; Sun, Haiyan; Xu, Fangsen; Zhang, Xuejiang; Liu, Shengyi

    2011-03-01

    In an attempt to determine the adaptation strategy to phosphorous (Pi) deficiency in oilseed rape, comparative proteome analyses were conducted to investigate the differences of metabolic changes in two oilseed rape genotypes with different tolerance to low phosphorus (LP). Generally in either roots or leaves, there existed few low phosphorus (LP)-induced proteins shared in the two lines. The LP-tolerant genotype 102 maintained higher Pi concentrations than LP-sensitive genotype 105 when growing hydroponically under the 5-μM phosphorus condition. In 102 we observed the downregulation of the proteins related to gene transcription, protein translation, carbon metabolism, and energy transfer in leaves and roots, and the downregulation of proteins related to leaf growth and root cellular organization. But the proteins related to the formation of lateral root were upregulated, such as the auxin-responsive family proteins in roots and the sucrose-phosphate synthase-like protein in roots and leaves. On the other hand, the LP-sensitive genotype 105 maintained the low level of Pi concentrations and suffered high oxidative pressure under the LP condition, and stress-shocking proteins were pronouncedly upregulated such as the proteins for signal transduction, gene transcription, secondary metabolism, universal stress family proteins, as well as the proteins involved in lipid oxygenation and the disease resistance in both leaves and roots. Although the leaf proteins for growth in 105 were downregulated, the protein expressions in roots related to glycolysis and tricarboxylic acid (TCA) cycle were enhanced to satisfy the requirement of organic acid secretion. PMID:21110039

  5. Species-specific variation in the phosphorus nutritional sources by microphytoplankton in a Mediterranean estuary

    Directory of Open Access Journals (Sweden)

    MARLY CAROLINA MARTINEZ SOTO

    2015-08-01

    Full Text Available We investigated the species-specific phosphorus (P nutrition sources in the microphytoplankton community in the Mahon estuary (Minorca, Western Mediterranean in 2011, under two contrasting hydrographic scenarios. Estuarine flow, nutrient concentrations, phytoplankton community composition and enzyme-labeled fluorescence (ELF were measured in June and October, corresponding to the beginning and the end of summer. Dissolved inorganic nitrogen (DIN and inorganic phosphate (Pi exhibited enhanced concentrations in the inner estuary where N:P molar ratios suggested P-limitation in both surveys. Pi was low and variable (0.09±0.02 μmol•l-1 in June and 0.06±0.02 μmol•l-1 in October, whereas organic phosphorus remained a more reliable P source. Even though ambient Pi concentrations were slightly higher on June, when the microphytoplankton assemblage was dominated by dinoflagellates, the percentage of cells expressing ELF labeling was notably higher (65% of total cells than in October (12%, when the presence of diatoms characterized the microphytoplankton community. ELF was mainly expressed by dinoflagellate taxa, whereas diatoms only expressed significant AP in the inner estuary during the June survey. A P-addition bioassay in which response of AP to Pi enrichment was evaluated showed remarkable reduction in AP with increasing Pi. However, some dinoflagellate species maintained AP even when Pi was supplied in excess. We suggest that in the case of some dinoflagellate species AP is not as tightly controlled by ambient Pi as previously believed. AP activity in these species could indicate selective use of organic phosphorus, or slow metabolic response to changes in P forms, rather than physiological stress to low Pi availability. We emphasize the importance of identifying the links between the different P sources and the species-specific requirements, in order to understand the ecological response to anthropogenic biogeochemical perturbations.

  6. Microbial ureolysis in the seawater-catalysed urine phosphorus recovery system: Kinetic study and reactor verification.

    Science.gov (United States)

    Tang, Wen-Tao; Dai, Ji; Liu, Rulong; Chen, Guang-Hao

    2015-12-15

    Our previous study has confirmed the feasibility of using seawater as an economical precipitant for urine phosphorus (P) precipitation. However, we still understand very little about the ureolysis in the Seawater-based Urine Phosphorus Recovery (SUPR) system despite its being a crucial step for urine P recovery. In this study, batch experiments were conducted to investigate the kinetics of microbial ureolysis in the seawater-urine system. Indigenous bacteria from urine and seawater exhibited relatively low ureolytic activity, but they adapted quickly to the urine-seawater mixture during batch cultivation. During cultivation, both the abundance and specific ureolysis rate of the indigenous bacteria were greatly enhanced as confirmed by a biomass-dependent Michaelis-Menten model. The period for fully ureolysis was decreased from 180 h to 2.5 h after four cycles of cultivation. Based on the successful cultivation, a lab-scale SUPR reactor was set up to verify the fast ureolysis and efficient P recovery in the SUPR system. Nearly complete urine P removal was achieved in the reactor in 6 h without adding any chemicals. Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis revealed that the predominant groups of bacteria in the SUPR reactor likely originated from seawater rather than urine. Moreover, batch tests confirmed the high ureolysis rates and high phosphorus removal efficiency induced by cultivated bacteria in the SUPR reactor under seawater-to-urine mixing ratios ranging from 1:1 to 9:1. This study has proved that the enrichment of indigenous bacteria in the SUPR system can lead to sufficient ureolytic activity for phosphate precipitation, thus providing an efficient and economical method for urine P recovery.

  7. Pyromineralization of soil phosphorus in savanna ecosystems

    Science.gov (United States)

    Hartshorn, A.; Coetsee, C.; Chadwick, O.

    2007-12-01

    The weathering of rock supplies phosphorus (P) to ecosystems. Phosphorus limitation of ecosystems can be severe in thicker or older soils, where soil production rates from rock and therefore release of P is slower than in thinner or younger soils. Limitation may be especially pronounced in drier ecosystems that are experiencing increasing N deposition. Our savanna field sites in Kruger National Park, South Africa meet all three of these criteria: soil residence times average 250 ky, the climate is semiarid, and N inputs average 20 kg ha-1 y-1. Not all soil P is plant-available, and because our field sites experience occasional fires, our objectives were to quantify the importance of pyromineralization of soil P, the transfer by fire of soil P from recalcitrant to labile (HCO3- extractable) pools. We quantified these soil P pools using a modified Hedley scheme (an array of chemical extractants). Three sets of soils were fractionated: 1. soils from 10 profiles along an intensively studied hillslope, bracketing a pronounced structural and functional ecotone; 2. surface soils from these 10 profiles after a simulated burn; and 3. surface soils from the Shabeni Experimental Plots, where 4 fire treatments have been maintained for decades: no fire, annual fire in the dry season, triennial fire in the dry season, and triennial fire in the wet season. Total P for hillslope soils ranged from 45 to 135 g m-2 (to 50 cm depth) and from 8 to 15 g m-2 (to 5 cm depth). Total soil P was lowest in midslope soils, where upslope sandy soils dominated by broad-leafed vegetation shift abruptly to downslope clayey soils with fine-leafed vegetation. Simulated fire for the hillslope soils reduced total P slightly, but boosted labile P by 1.7 g m-2 (to 5 cm), representing 17% of total P in the surface 5 cm. This pyromineralization effect was not uniform across the hillslope: downslope soils gained about 50% more labile P than midslope soils with simulated burning. With a fire return interval

  8. Remaining phosphorus estimated by pedotransfer function

    Directory of Open Access Journals (Sweden)

    Joice Cagliari

    2011-02-01

    Full Text Available Although the determination of remaining phosphorus (Prem is simple, accurate values could also be estimated with a pedotransfer function (PTF aiming at the additional use of soil analysis data and/or Prem replacement by an even simpler determination. The purpose of this paper was to develop a pedotransfer function to estimate Prem values of soils of the State of São Paulo based on properties with easier or routine laboratory determination. A pedotransfer function was developed by artificial neural networks (ANN from a database of Prem values, pH values measured in 1 mol L-1 NaF solution (pH NaF and soil chemical and physical properties of samples collected during soil classification activities carried out in the State of São Paulo by the Agronomic Institute of Campinas (IAC. Furthermore, a pedotransfer function was developed by regressing Prem values against the same predictor variables of the ANN-based PTF. Results showed that Prem values can be calculated more accurately with the ANN-based pedotransfer function with the input variables pH NaF values along with the sum of exchangeable bases (SB and the exchangeable aluminum (Al3+ soil content. In addition, the accuracy of the Prem estimates by ANN-based PTF were more sensitive to increases in the experimental database size. Although the database used in this study was not comprehensive enough for the establishment of a definitive pedotrasnfer function for Prem estimation, results indicated the inclusion of Prem and pH NaF measurements among the soil testing evaluations as promising ind order to provide a greater database for the development of an ANN-based pedotransfer function for accurate Prem estimates from pH NaF, SB, and Al3+ values.

  9. Forms of organic phosphorus in wetland soils

    Directory of Open Access Journals (Sweden)

    A. W. Cheesman

    2014-06-01

    Full Text Available Phosphorus (P cycling in freshwater wetlands is dominated by biological mechanisms, yet there has been no comprehensive examination of the forms of biogenic P (i.e. forms derived from biological activity in wetland soils. We used solution 31P NMR spectroscopy to identify and quantify P forms in surface soils of 28 palustrine wetlands spanning a range of climatic, hydro-geomorphic and vegetation types. Total P concentrations ranged between 51 and 3516 μg P g, of which an average of 58% was extracted in a single-step NaOH–EDTA extraction procedure. The extracts contained a broad range of P forms, including phosphomonoesters (averaging 24% of the total soil P, phosphodiesters (averaging 10% of total P, phosphonates (up to 4% of total P, and both pyrophosphate and long-chain polyphosphates (together averaging 6% of total P. Soil P composition was predicted by two key biogeochemical properties: organic matter content and pH. For example, stereoisomers of inositol hexakisphosphate were detected exclusively in acidic soils with high mineral content, while phosphonates were detected in soils from a broad range of vegetation and hydrogeomorphic types, but only under acidic conditions. Conversely inorganic polyphosphates occurred in a broad range of wetland soils and their abundance appears to reflect more broadly that of a "substantial" and presumably active microbial community with a significant relationship between total inorganic polyphosphates and microbial biomass P. We conclude that soil P composition varies markedly among freshwater wetlands, but can be predicted by fundamental soil properties.

  10. Alkaline phosphatase activity and the phosphorus mineralization rate of Lake Taihu

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The phosphorus fractions, the alkaline phosphatase activity (APA) and other water chemical parameters were concomitantly monitored from April 2003 to October 2004 in different ecotype sites of Lake Taihu. During the stages of algae growth, the phosphorus fractions and their relationships with APA in different ecotype sites were discussed and the phosphorus mineralization rate was calculated. In the water of Lake Taihu, most of the phosphorus (70.2%) could be attributed to the suspended particulate phosphorus, while the dissolved reactive phosphorus (DRP) seems to contribute less than 7%. About 58% of the total phosphorus, however, can be hydrolyzed as inorganic phosphate to compensate for phosphorus deficiency of algae and bacteria growth. During the different algae growth stages, the APA and its Kinetic parameters were varied significantly between different ecotype sites of Lake Taihu. This trend is also visible by comparing the phosphorus mineralization rate,and the most rapidly phosphorus turnover time is only several minutes. The fast recycle of phosphorus can, to some extent, be explained that the phosphorus source of algal blooms. The phytoplankton seems to compensate for phosphorus deficiency by using the alkaline phosphatase to hydrolyze phosphomonoesters.

  11. The "phosphorus pyramid": a visual tool for dietary phosphate management in dialysis and CKD patients.

    Science.gov (United States)

    D'Alessandro, Claudia; Piccoli, Giorgina B; Cupisti, Adamasco

    2015-01-20

    Phosphorus retention plays a pivotal role in the onset of mineral and bone disorders (MBD) in chronic kidney disease (CKD). Phosphorus retention commonly occurs as a result of net intestinal absorption exceeding renal excretion or dialysis removal. The dietary phosphorus load is crucial since the early stages of CKD, throughout the whole course of the disease, up to dialysis-dependent end-stage renal disease.Agreement exits regarding the need for dietary phosphate control, but it is quite challenging in the real-life setting. Effective strategies to control dietary phosphorus intake include restricting phosphorus-rich foods, preferring phosphorus sourced from plant origin, boiling as the preferred cooking procedure and avoiding foods with phosphorus-containing additives. Nutritional education is crucial in this regard.Based on the existing literature, we developed the "phosphorus pyramid", namely a novel, visual, user-friendly tool for the nutritional education of patients and health-care professionals. The pyramid consists of six levels in which foods are arranged on the basis of their phosphorus content, phosphorus to protein ratio and phosphorus bioavailability. Each has a colored edge (from green to red) that corresponds to recommended intake frequency, ranging from "unrestricted" to "avoid as much as possible".The aim of the phosphorus pyramid is to support dietary counseling in order to reduce the phosphorus load, a crucial aspect of integrated CKD-MBD management.

  12. Population dynamics of bacteria for phosphorus removal in sequencing batch reactor (SBR) activated sludge processes. Kaibunshiki kassei odeiho ni okeru datsu rin tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Okada, M.; Ueno, Y.; Lin, C.; Murakami, A. (Tokyo University of Agriculture and Technology, Tokyo (Japan))

    1990-01-10

    As the phosphorus removal processes, chemical methods and biological methods are considered. This paper discussed a biological phosphorus removal method. Laboratory experiments of phosphorus removal in sequencing batch reactor (SBR) activated sludge processes were operated using synthetic waste water to clarify the effects of solid retention time (SRT) and organic substrates on the accumulation of bacteria having phosphorus removal ability (bio-P-bacteria). The accumulation of bio-P-bacteria was enhanced by large fluctuation in concentration of organic substances in the reactor fed in a short period of time under anaerobic condition. However, the accumulation did not be enhanced in the reactor operated with SRT less than 25 d. The specific growth rates of bio-P-bacteria were estimated to a range from 0.033/d to 0.035/d in the SBR activated sludge processes fed with glucose and polypeptone as substrates. Therefore, large SRT is necessary for the accumulation of bio-P-bacteria. 18 refs., 10 figs., 1 tab.

  13. Transport properties of ultrathin black phosphorus on hexagonal boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Doganov, Rostislav A.; Özyilmaz, Barbaros [Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, 117546 Singapore (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore (Singapore); Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 28 Medical Drive, 117456 Singapore (Singapore); Koenig, Steven P.; Yeo, Yuting [Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, 117546 Singapore (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore (Singapore); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2015-02-23

    Ultrathin black phosphorus, or phosphorene, is a two-dimensional material that allows both high carrier mobility and large on/off ratios. Similar to other atomic crystals, like graphene or layered transition metal dichalcogenides, the transport behavior of few-layer black phosphorus is expected to be affected by the underlying substrate. The properties of black phosphorus have so far been studied on the widely utilized SiO{sub 2} substrate. Here, we characterize few-layer black phosphorus field effect transistors on hexagonal boron nitride—an atomically smooth and charge trap-free substrate. We measure the temperature dependence of the field effect mobility for both holes and electrons and explain the observed behavior in terms of charged impurity limited transport. We find that in-situ vacuum annealing at 400 K removes the p-doping of few-layer black phosphorus on both boron nitride and SiO{sub 2} substrates and reduces the hysteresis at room temperature.

  14. Phosphorus recovery from municipal solid waste incineration fly ash.

    Science.gov (United States)

    Kalmykova, Yuliya; Fedje, K Karlfeldt

    2013-06-01

    The potential of phosphorus (P) recycling from municipal solid waste incineration (MSWI) residue is investigated. Vast and ever increasing amounts of incineration residues are produced worldwide; these are an environmental burden, but also a resource, as they are a major sink for the material flows of society. Due to strict environmental regulations, in combination with decreasing landfilling space, the disposal of the MSWI residues is problematic. At the same time, resource scarcity is recognized as a global challenge for the modern world, and even more so for future generations. This paper reports on the methods and efficiency of P extraction from MSWI fly ash by acid and base leaching and precipitation procedures. Phosphorus extracted from the MSWI residues generated each year could meet 30% of the annual demand for mineral phosphorus fertiliser in Sweden, given a recovery rate of 70% achieved in this initial test. The phosphorus content of the obtained product is slightly higher than in sewage sludge, but due to the trace metal content it is not acceptable for application to agricultural land in Sweden, whereas application in the rest of the EU would be possible. However, it would be preferable to use the product as a raw material to replace rock phosphate in fertilizer production. Further development is currently underway in relation to procedure optimization, purification of the phosphorus product, and the simultaneous recovery of other resources. PMID:23490361

  15. Removing Phosphorus from Aqueous Solutions Using Lanthanum Modified Pine Needles.

    Directory of Open Access Journals (Sweden)

    Xianze Wang

    Full Text Available The renewable pine needles was used as an adsorbent to remove phosphorus from aqueous solutions. Using batch experiments, pine needles pretreated with alkali-isopropanol (AI failed to effectively remove phosphorus, while pine needles modified with lanthanum hydroxide (LH showed relatively high removal efficiency. LH pine needles were effective at a wide pH ranges, with the highest removal efficiency reaching approximately 85% at a pH of 3. The removal efficiency was kept above 65% using 10 mg/L phosphorus solutions at desired pH values. There was no apparent significant competitive behavior between co-existing anions of sulfate, nitrate, and chloride (SO4(2-, NO3(- and Cl(-; however, CO3(2- exhibited increased interfering behavior as concentrations increased. An intraparticle diffusion model showed that the adsorption process occurred in three phases, suggesting that a boundary layer adsorption phenomena slightly affected the adsorption process, and that intraparticle diffusion was dominant. The adsorption process was thermodynamically unfavorable and non-spontaneous; temperature increases improved phosphorus removal. Total organic carbon (TOC assays indicated that chemical modification reduced the release of soluble organic compounds from 135.6 mg/L to 7.76 mg/L. This new information about adsorption performances provides valuable information, and can inform future technological applications designed to remove phosphorus from aqueous solutions.

  16. Removing Phosphorus from Aqueous Solutions Using Lanthanum Modified Pine Needles

    Science.gov (United States)

    Wang, Xianze; Liu, Zhongmou; Liu, Jiancong; Huo, Mingxin; Huo, Hongliang; Yang, Wu

    2015-01-01

    The renewable pine needles was used as an adsorbent to remove phosphorus from aqueous solutions. Using batch experiments, pine needles pretreated with alkali-isopropanol (AI) failed to effectively remove phosphorus, while pine needles modified with lanthanum hydroxide (LH) showed relatively high removal efficiency. LH pine needles were effective at a wide pH ranges, with the highest removal efficiency reaching approximately 85% at a pH of 3. The removal efficiency was kept above 65% using 10 mg/L phosphorus solutions at desired pH values. There was no apparent significant competitive behavior between co-existing anions of sulfate, nitrate, and chloride (SO42-, NO3- and Cl-); however, CO32- exhibited increased interfering behavior as concentrations increased. An intraparticle diffusion model showed that the adsorption process occurred in three phases, suggesting that a boundary layer adsorption phenomena slightly affected the adsorption process, and that intraparticle diffusion was dominant. The adsorption process was thermodynamically unfavorable and non-spontaneous; temperature increases improved phosphorus removal. Total organic carbon (TOC) assays indicated that chemical modification reduced the release of soluble organic compounds from 135.6 mg/L to 7.76 mg/L. This new information about adsorption performances provides valuable information, and can inform future technological applications designed to remove phosphorus from aqueous solutions. PMID:26630014

  17. Simultaneous denitrifying phosphorus accumulation in a sequencing batch reactor

    Institute of Scientific and Technical Information of China (English)

    YUAN Linjiang; HAN Wei; WANG Lei; YANG Yongzhe; WANG Zhiying

    2007-01-01

    In order to achieve simultaneous nitrogen and phosphorus removal in the biological treatment process,denitrifying phosphorus accumulation(DNPA)and its affecting factors were studied in a sequencing batch reactor(SBR)with synthetic wastewater.The results showed that when acetate was used as the sole carbon resource in the influent.the sludge acclimatized under anaerobic/aerobic operation had good phosphorus removal ability.Denitrifying phosphorus accumulation was observed soon when fed with nitrate instead of aeration following the anaerobic stage,which is a vital premise to DNPA.If DNPA sludge is fed with nitrate prior to the anaerobic stage,the DNPA would weaken or even disappear.At the high concen tration of nitrate fed in the anoxic stage,the longer anoxic time needed,the better the DNPA was.Induced DNPA did not disappear even though an aerobic stage followed the anoxic stage,but the shorter the aerobic stage lasted,the higher the proportions of phosphorus removal via DNPA to total removal.

  18. Remediation of phosphorus from electric furnace waste streams

    International Nuclear Information System (INIS)

    Electrothermal production of elemental phosphorus (P4) generates substantial amounts of highly toxic phossy water sludge, slag and other gaseous wastes. Because of their high phosphorus content the sludges pose potential fire hazards. In the absence of a reliable processing technology, large amounts of these hazardous wastes are accumulated at an annual rate of 1.5-2.5 million tons from current and past operations. The accumulated sludges are stored in ponds or in special containment vessels in 30 locations in 18 states including Alabama, California, Tennessee, Idaho and Montana. Serious water pollution problems will result unless these wastes are given extensive treatment to remove the elemental phosphorus. Federal regulations prohibit permanent storage of flammable wastes. This paper reports that recently, researchers at the University of Alabama have developed a two-step method for the treatment of phosphorus sludge that includes bulk removal of phosphorus by physical separation techniques followed by remediation of the residual P4 in the sludge using a novel wet air oxidation technique known as HSAD

  19. Atomic and electronic structure of exfoliated black phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ryan J.; Topsakal, Mehmet; Jeong, Jong Seok; Wentzcovitch, Renata M.; Mkhoyan, K. Andre, E-mail: mkhoyan@umn.edu [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Low, Tony; Robbins, Matthew C.; Haratipour, Nazila; Koester, Steven J. [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2015-11-15

    Black phosphorus, a layered two-dimensional crystal with tunable electronic properties and high hole mobility, is quickly emerging as a promising candidate for future electronic and photonic devices. Although theoretical studies using ab initio calculations have tried to predict its atomic and electronic structure, uncertainty in its fundamental properties due to a lack of clear experimental evidence continues to stymie our full understanding and application of this novel material. In this work, aberration-corrected scanning transmission electron microscopy and ab initio calculations are used to study the crystal structure of few-layer black phosphorus. Directly interpretable annular dark-field images provide a three-dimensional atomic-resolution view of this layered material in which its stacking order and all three lattice parameters can be unambiguously identified. In addition, electron energy-loss spectroscopy (EELS) is used to measure the conduction band density of states of black phosphorus, which agrees well with the results of density functional theory calculations performed for the experimentally determined crystal. Furthermore, experimental EELS measurements of interband transitions and surface plasmon excitations are also consistent with simulated results. Finally, the effects of oxidation on both the atomic and electronic structure of black phosphorus are analyzed to explain observed device degradation. The transformation of black phosphorus into amorphous PO{sub 3} or H{sub 3}PO{sub 3} during oxidation may ultimately be responsible for the degradation of devices exposed to atmosphere over time.

  20. Phosphorus Recovery Using Zirconium-Loaded Saponified Orange Juice Residue

    Science.gov (United States)

    Harada, Hiroyuki; Kondo, Mitsunori; Biswas, Biplob K.; Ohura, Seichirou; Inoue, Katsutoshi; Ishikawa, Susumu; Kawakita, Hidetaka; Ohto, Keisuke

    Zirconium was immobilized to orange juice residue, to investigate the feasibility of using zirconium-loaded saponified orange juice residue (Zr-SOJR) for phosphorus recovery from secondary effluent and the extraction solution from incinerated sewage sludge ash by using H2SO4 and HCl. These had phosphorus concentrations of 68.2 mg/dm3 and 5.9 mg/dm3, respectively. The phosphorus removal rate secondary effluent increased with an increasing solid/liquid ratio in batch experiments. The adsorption capacity of Zr-SOJR was also compared with those obtained using a synthetic phosphorus solution and using zirconium-loaded ferrite. The prepared absorbent was effective for phosphorus removal and exhibited a reasonably high sorption capacity, twice that of zirconium ferrite. Secondary effluent was treated by packed column, and this reached break-through after 300 bed volumes. The results from phosphorous extraction from the ash indicate that can be treated with acid to efficiently recover phosphorous and thus can be absorbed by Zr-SOJR.