Asparagus stem as a new lignocellulosic biomass feedstock for anaerobic digestion: increasing hydrolysis rate, methane production and biodegradability by alkaline pretreatment.

Science.gov (United States)

Chen, Xiaohua; Gu, Yu; Zhou, Xuefei; Zhang, Yalei

2014-07-01

Recently, anaerobic digestion of lignocellulosic biomass for methane production has attracted considerable attention. However, there is little information regarding methane production from asparagus stem, a typical lignocellulosic biomass, by anaerobic digestion. In this study, alkaline pretreatment of asparagus stem was investigated for its ability to increase hydrolysis rate and methane production and to improve biodegradability (BD). The hydrolysis rate increased with increasing NaOH dose, due to higher removal rates of lignin and hemicelluloses. However, the optimal NaOH dose was 6% (w/w) according to the specific methane production (SMP). Under this condition, the SMP and the technical digestion time of the NaOH-treated asparagus stem were 242.3 mL/g VS and 18 days, which were 38.4% higher and 51.4% shorter than those of the untreated sample, respectively. The BD was improved from 40.1% to 55.4%. These results indicate that alkaline pretreatment could be an efficient method for increasing methane production from asparagus stem. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhanced biogas production from penicillin bacterial residue by thermal-alkaline pretreatment

International Nuclear Information System (INIS)

Zhong, Weizhang; Li, Guixia; Gao, Yan; Li, Zaixing; Geng, Xiaoling; Li, Yubing; Yang, Jingliang; Zhou, Chonghui

2015-01-01

In this study, the orthogonal experimental design was used to determine the optimum conditions for the effect of thermal alkaline; pretreatment on the anaerobic digestion of penicillin bacterial residue. The biodegradability of the penicillin; bacterial residue was evaluated by biochemical methane potential tests in laboratory. The optimum values of temperature,; alkali concentration, pretreatment time and moisture content for the thermal-alkaline pretreatment were determined as; 70 °C, 6% (w/v), 30 min, and 85%, respectively. Thermal-alkaline pretreatment could significantly enhance the soluble; chemical oxygen demand solubilization, the suspended solid solubilization and the biodegradability. Biogas production; was enhanced by the thermal-alkaline pretreatment, probably as a result of the breakdown of cell walls and membranes of; micro-organisms, which may facilitate the contact between organic molecules and anaerobic microorganisms.; Keywords: penicillin bacterial residue; anaerobic digestion; biochemical methane potential tests; pretreatment

Mechanistic studies of the alkaline degradation of cellulose in cement

International Nuclear Information System (INIS)

Greenfield, B.F.; Robertson, G.P.; Spindler, M.W.; Harrison, W.N.; Somers, P.J.

1993-07-01

The alkaline degradation of cellulose-based materials under conditions simulating those of a deep underground radioactive waste repository has been investigated. A number of key degradation products, of which 2-C-(hydroxymethyl)-3-deoxy-D-pentonic acid (isosaccharinic acid) is the most important, have been synthesised, and the solubilities of their plutonium complexes have been determined. Analysis of leachates of anaerobically degraded cellulose has shown concentrations of organic acids which are broadly consistent with the enhanced plutonium solubilities found in these leachates. Reaction mechanisms have been identified that can lead to isosaccharinic acid production by non-oxidative transformations, which may be catalysed by some divalent cations. (Author)

Full-scale production of VFAs from sewage sludge by anaerobic alkaline fermentation to improve biological nutrients removal in domestic wastewater.

Science.gov (United States)

Liu, He; Han, Peng; Liu, Hongbo; Zhou, Guangjie; Fu, Bo; Zheng, Zhiyong

2018-07-01

A full-scale project of thermal-alkaline pretreatment and alkaline fermentation of sewage sludge was built to produce volatile fatty acids (VFAs) which was then used as external carbon source for improving biological nitrogen and phosphorus removals (BNPR) in wastewater plant. Results showed this project had efficient and stable performances in VFA production, sludge reduce and BNPR. Hydrolysis rate in pretreatment, VFAs yield in fermentation and total VS reduction reached 68.7%, 261.32 mg COD/g VSS and 54.19%, respectively. Moreover, fermentation liquid with VFA presented similar efficiency as acetic acid in enhancing BNPR, obtaining removal efficiencies of nitrogen and phosphorus up to 72.39% and 89.65%, respectively. Finally, the project also presented greater economic advantage than traditional processes, and the net profits for VFAs and biogas productions are 9.12 and 3.71 USD/m 3 sludge, respectively. Long-term operation indicated that anaerobic alkaline fermentation for VFAs production is technically and economically feasible for sludge carbon recovery. Copyright © 2018 Elsevier Ltd. All rights reserved.

Physiologically anaerobic microorganisms of the deep subsurface

Energy Technology Data Exchange (ETDEWEB)

Stevens, S.E. Jr.; Chung, K.T.

1991-06-01

This study seeks to determine numbers, diversity, and morphology of anaerobic microorganisms in 15 samples of subsurface material from the Idaho National Engineering Laboratory, in 18 samples from the Hanford Reservation and in 1 rock sample from the Nevada Test Site; set up long term experiments on the chemical activities of anaerobic microorganisms based on these same samples; work to improve methods for the micro-scale determination of in situ anaerobic microbial activity;and to begin to isolate anaerobes from these samples into axenic culture with identification of the axenic isolates.

Improving methane production from anaerobic digestion of Pennisetum Hybrid by alkaline pretreatment.

Science.gov (United States)

Kang, Xihui; Sun, Yongming; Li, Lianhua; Kong, Xiaoying; Yuan, Zhenhong

2018-05-01

Alkaline pretreatment with NaOH was used to improve methane yield from Pennisetum Hybrid. The pretreatments were carried out with different NaOH solutions (2-8% w/w) at three temperatures (35, 55 and 121 °C) for different periods of time (24, 24 and 1 h). All treated and untreated Pennisetum Hybrid were digested under mesophilic conditions (37 °C) to biogas, significant effects of the pretreatments on the yield of methane were observed. Results showed the modified Gompertz equation was reliable (determination coefficients (R 2 ) greater than 0.96) to describe the kinetic behavior of anaerobic digestion of Pennisetum Hybrid. The best result, obtained by the treatment at 35 °C 2% NaOH for 24 h, resulted in the methane yield of 301.7 mL/g VS, corresponding to 21.0% improvement in the methane yield. Compositional, SEM, XRD and FTIR analysis confirmed that lignin removal, structural modification and cellulose crystalline variation were responsible for the improvement. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparison of the anaerobic microbiota of deep-water Geodia spp. and sandy sediments in the Straits of Florida.

Science.gov (United States)

Brück, Wolfram M; Brück, Thomas B; Self, William T; Reed, John K; Nitecki, Sonja S; McCarthy, Peter J

2010-05-01

Marine sediments and sponges may show steep variations in redox potential, providing niches for both aerobic and anaerobic microorganisms. Geodia spp. and sediment specimens from the Straits of Florida were fixed using paraformaldehyde and 95% ethanol (v/v) for fluorescence in situ hybridization (FISH). In addition, homogenates of sponge and sediment samples were incubated anaerobically on various cysteine supplemented agars. FISH analysis showed a prominent similarity of microbiota in sediments and Geodia spp. samples. Furthermore, the presence of sulfate-reducing and annamox bacteria as well as other obligate anaerobic microorganisms in both Geodia spp. and sediment samples were also confirmed. Anaerobic cultures obtained from the homogenates allowed the isolation of a variety of facultative anaerobes, primarily Bacillus spp. and Vibrio spp. Obligate anaerobes such as Desulfovibrio spp. and Clostridium spp. were also found. We also provide the first evidence for a culturable marine member of the Chloroflexi, which may enter into symbiotic relationships with deep-water sponges such as Geodia spp. Resuspended sediment particles, may provide a source of microorganisms able to associate or form a symbiotic relationship with sponges.

Physiologically anaerobic microorganisms of the deep subsurface. Progress report, June 1, 1991--May 31, 1992

Energy Technology Data Exchange (ETDEWEB)

Stevens, S.E. Jr.; Chung, K.T.

1992-06-01

A variety of different media were used to isolate facultatively (FAB) and obligately anaerobic bacteria (OAB). These bacteria were isolated from core subsamples obtained from boreholes at the Idaho National Engineering Lab. (INEL) or at the Hanford Lab. (Yakima). Core material was sampled at various depths to 600 feet below the surface. All core samples with culturable bacteria contained at least FAB making thisthe most common physiological type of anaerobic bacteria present in the deep subsurface at these two sites. INEL core samples are characterized by isolates of both FAB and OAB. No isolates of acetogenic, methanogenic, or sulfate reducing bacteria were obtained. Yakima core samples are characterized by a marked predominance of FAB in comparison to OAB. In addition, isolates of acetogenic, methanogenic, and sulfate reducing bacteria were obtained. The Yakima site has the potential for complete anaerobic mineralization of organic compounds whereas this potential appears to be lacking at INEL.

Pertechnetate immobilization in aqueous media with hydrogen sulfide under anaerobic and aerobic environments

International Nuclear Information System (INIS)

Liu, Y.; Jurisson, S.; Terry, J.

2007-01-01

The basic chemistry for the immobilization of pertechnetate (TcO 4 - ) by hydrogen sulfide was investigated in aqueous solution under both aerobic and anaerobic environments. Pertechnetate immobilization was acid dependent, with accelerated rates and increased immobilization yields as the acid concentration increased. Oxygen had no effect under acidic conditions. Under anaerobic alkaline conditions, the pH, and therefore the speciation of sulfide, was the determining factor on the immobilization of pertechnetate. Only 53% of the TcO 4 - was immobilized at pH 8, while the yield increased to 83% at pH 9 as HS - became the dominant sulfide species. The immobilization yield then decreased to 73% at pH 13. No reaction was observed between TcO 4 - and sulfide under aerobic alkaline conditions, indicating that oxygen suppressed this reaction. Pertechnetate immobilization was found to be first order with respect to both sulfide and pertechnetate in acidic solutions, and in alkaline solution under anaerobic conditions. The results of stoichiometry studies and product analysis under alkaline anaerobic environments indicated that Tc 2 S 7 was obtained at pH 9. EXAFS (extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure) studies suggested that the samples obtained from acidic, aerobic solution and alkaline anaerobic solution were both Tc 2 S 7 . The stability of Tc 2 S 7 is affected by O 2 with accelerated dissolution at high pH. (orig.)

Effect of alkaline pretreatment on anaerobic digestion of solid wastes

International Nuclear Information System (INIS)

Lopez Torres, M.; Espinosa Llorens, Ma. del C.

2008-01-01

The introduction of the anaerobic digestion for the treatment of the organic fraction of municipal solid waste (OFMSW) is currently of special interest. The main difficulty in the treatment of this waste fraction is its biotransformation, due to the complexity of organic material. Therefore, the first step must be its physical, chemical and biological pretreatment for breaking complex molecules into simple monomers, to increase solubilization of organic material and improve the efficiency of the anaerobic treatment in the second step. This paper describes chemical pretreatment based on lime addition (Ca(OH) 2 ), in order to enhance chemical oxygen demand (COD) solubilization, followed by anaerobic digestion of the OFMSW. Laboratory-scale experiments were carried out in completely mixed reactors, 1 L capacity. Optimal conditions for COD solubilization in the first step of pretreatment were 62.0 mEq Ca(OH) 2 /L for 6.0 h. Under these conditions, 11.5% of the COD was solubilized. The anaerobic digestion efficiency of the OFMSW, with and without pretreatment, was evaluated. The highest methane yield under anaerobic digestion of the pretreated waste was 0.15 m 3 CH 4 /kg volatile solids (VS), 172.0% of the control. Under that condition the soluble COD and VS removal were 93.0% and 94.0%, respectively. The results have shown that chemical pretreatment with lime, followed by anaerobic digestion, provides the best results for stabilizing the OFMSW

Combined electrical-alkali pretreatment to increase the anaerobic hydrolysis rate of waste activated sludge during anaerobic digestion

International Nuclear Information System (INIS)

Zhen, Guangyin; Lu, Xueqin; Li, Yu-You; Zhao, Youcai

2014-01-01

Highlights: • Combined electrical-alkali pretreatment for improving sludge anaerobic digestion was proposed. • Combined process enhanced the cell lysis, biopolymers releases, and thus sludge disintegration. • Increased solubilization of sludge increased the anaerobic hydrolysis rate. • Increased solubilization does not always induce an improved anaerobic digestion efficiency. - Abstract: Pretreatment can be used prior to anaerobic digestion to improve the efficiency of waste activated sludge (WAS) digestion. In this study, electrolysis and a commonly used pretreatment method of alkaline (NaOH) solubilization were integrated as a pretreatment method for promoting WAS anaerobic digestion. Pretreatment effectiveness of combined process were investigated in terms of disintegration degree (DD SCOD ), suspended solids (TSS and VSS) removals, the releases of protein (PN) and polysaccharide (PS), and subsequent anaerobic digestion as well as dewaterability after digestion. Electrolysis was able to crack the microbial cells trapped in sludge gels and release the biopolymers (PN and PS) due to the cooperation of alkaline solubilization, enhancing the sludge floc disintegration/solubilization, which was confirmed by scanning electron microscopy (SEM) analysis. Biochemical methane potential (BMP) assays showed the highest methane yield was achieved with 5 V plus pH 9.2 pretreatment with up to 20.3% improvement over the non-pretreated sludge after 42 days of mesophilic operation. In contrast, no discernible improvements on anaerobic degradability were observed for the rest of pretreated sludges, probably due to the overmuch leakage of refractory soluble organics, partial chemical mineralization of solubilized compounds and sodium inhibition. The statistical analysis further indicated that increased solubilization induced by electrical-alkali pretreatment increased the first-order anaerobic hydrolysis rate (k hyd ), but had no, or very slight enhancement on WAS ultimate

Enhancing anaerobic digestion of waste activated sludge by pretreatment: effect of volatile to total solids.

Science.gov (United States)

Wang, Xiao; Duan, Xu; Chen, Jianguang; Fang, Kuo; Feng, Leiyu; Yan, Yuanyuan; Zhou, Qi

2016-01-01

In this study the effect of volatile to total solids (VS/TS) on anaerobic digestion of waste activated sludge (WAS) pretreated by alkaline, thermal and thermal-alkaline strategies was studied. Experimental results showed that the production of methane from sludge was increased with VS/TS. When anaerobic digesters were fed with sludge pretreated by the thermal-alkaline method, the average methane yield was improved from 2.8 L/d at VS/TS 0.35 to 4.7 L/d at VS/TS 0.56. Also, the efficiency of VS reduction during sludge anaerobic digestion varied between 18.9% and 45.6%, and increased gradually with VS/TS. Mechanism investigation of VS/TS on WAS anaerobic digestion suggested that the general activities of anaerobic microorganisms, activities of key enzymes related to sludge hydrolysis, acidification and methanogenesis, and the ratio of Archaea to Bacteria were all increased with VS/TS, showing good agreement with methane production.

Alkalinity production in intertidal sands intensified by lugworm bioirrigation.

Science.gov (United States)

Rao, Alexandra M F; Malkin, Sairah Y; Montserrat, Francesc; Meysman, Filip J R

2014-07-05

Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O 2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO 3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer.

Geochemical modeling of the influence of silicate mineral alteration on alkalinity production and carbonate precipitation

Science.gov (United States)

Herda, Gerhard; Kraemer, Stephan M.; Gier, Susanne; Meister, Patrick

2016-04-01

High CO2 partial pressure (pCO2) in deep rock reservoirs causes acidification of the porefluid. Such conditions occur during injection and subsurface storage of CO2 (to prevent the release of greenhouse gas) but also naturally in zones of strong methanogenic microbial activity in organic matter-rich ocean margin sediments. The acidic fluids are corrosive to carbonates and bear the risk of leakage of CO2 gas to the surface. Porefluid acidification may be moderated by processes that increase the alkalinity, i.e. that produce weak acid anions capable of buffering the acidification imposed by the CO2. Often, alkalinity increases as a result of anaerobic microbial activity, such as anaerobic oxidation of methane. However, on a long term the alteration of silicates, in particular, clay minerals, may be a more efficient mechanism of alkalinity production. Under altered temperature, pressure and porefluid composition at depth, clay minerals may change to thermodynamically more stable states, thereby increasing the alkalinity of the porefluid by partial leaching of Mg-(OH)2 and Ca-(OH)2 (e.g. Wallmann et al., 2008; Mavromatis et al., 2014). This alteration may even be enhanced by a high pCO2. Thus, silicate alteration can be essential for a long-term stabilization of volatile CO2 in the form of bicarbonate or may even induce precipitation of carbonate minerals, but these processes are not fully understood yet. The goal of this study is to simulate the alkalinity effect of silicate alteration under diagenetic conditions and high pCO2 by geochemical modeling. We are using the program PHREEQC (Parkhurst and Appelo, 2013) to generate high rock/fluid ratio characteristics for deep subsurface rock reservoirs. Since we are interested in the long-term evolution of diagenetic processes, over millions of years, we do not consider kinetics but calculate the theoretically possible equilibrium conditions. In a first step we are calculating the saturation state of different clay minerals

The influence and mechanism of influent pH on anaerobic co ...

African Journals Online (AJOL)

Two pilot-scale activated sludge systems consisting of an anaerobic baffled reactor (ABR) and an aerobic plug flow reactor (PFR) were operated with the aim of minimising excess sludge output of the activated sludge process through coupled alkaline hydrolysis and anaerobic digestion. Variations in the effluent of total ...

Alkaline-mechanical pretreatment process for enhanced anaerobic digestion of thickened waste activated sludge with a novel crushing device: Performance evaluation and economic analysis.

Science.gov (United States)

Cho, Si-Kyung; Ju, Hyun-Jun; Lee, Jeong-Gyu; Kim, Sang-Hyoun

2014-08-01

Although various pretreatments have been widely investigated to enhance the anaerobic digestion (AD) of waste activated sludge (WAS), economic feasibility issues have limited real-world applications. The authors examined the performance and economic analysis of an alkaline-mechanical process with a novel mechanical crushing device for thickened WAS pretreatment. The pretreatment at 40gTS/L, pH 13, and 90min reaction time achieved 64% of solubilization efficiency and 8.3 times higher CH4 yield than the control. In addition, a synergistic CH4 yield enhancement was observed when the pretreated and raw WAS were used together as feedstock, and the greatest synergy was observed at a volumetric mixture ratio of 50:50. Economic estimates indicate that up to 22% of WAS treatment costs would be saved by the installation of the suggested process. The experimental results clearly indicate that the alkaline-mechanical process would be highly effective and economically feasible for the AD of thickened WAS. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sulfate reduction controlled by organic matter availability in deep sediment cores from the saline, alkaline Lake Van (Eastern Anatolia, Turkey

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Clemens eGlombitza

2013-07-01

Full Text Available As part of the International Continental Drilling Program (ICDP deep lake drilling project PaleoVan, we investigated sulfate reduction (SR in deep sediment cores of the saline, alkaline (salinity 21.4 ‰, alkalinity 155 m mEq-1, pH 9.81 Lake Van, Turkey. The cores were retrieved in the Northern Basin (NB and at Ahlat Ridge (AR and reached a maximum depth of 220 m. Additionally, 65-75 cm long gravity cores were taken at both sites. Sulfate reduction rates (SRR were low (≤ 22 nmol cm-3 d-1 compared to lakes with higher salinity and alkalinity, indicating that salinity and alkalinity are not limiting SR in Lake Van. Both sites differ significantly in rates and depth distribution of SR. In NB, SRR are up to 10 times higher than at AR. Sulfate reduction (SR could be detected down to 19 meters below lake floor (mblf at NB and down to 13 mblf at AR. Although SRR were lower at AR than at NB, organic matter (OM concentrations were higher. In contrast, dissolved OM in the pore water at AR contained more macromolecular OM and less low molecular weight OM. We thus suggest, that OM content alone cannot be used to infer microbial activity at Lake Van but that quality of OM has an important impact as well. These differences suggest that biogeochemical processes in lacustrine sediments are reacting very sensitively to small variations in geological, physical or chemical parameters over relatively short distances. 

Synergistic effect of alkaline pretreatment and Fe dosing on batch anaerobic digestion of maize straw

International Nuclear Information System (INIS)

Khatri, Shailendra; Wu, Shubiao; Kizito, Simon; Zhang, Wanqin; Li, Jiaxi; Dong, Renjie

2015-01-01

Highlights: • Synergistic effect of NaOH treatment and Fe dosage to maize straw was investigated. • Combining NaOH treatment and Fe dosing resulted in 57% and 56% higher biogas and methane yield respectively. • Combined treatment shortened the technical digestion time from 48 days to 7 days. • Methane content did not differ significantly among the straw treatments. - Abstract: The synergistic effect of alkaline pretreatment and Fe dosing on anaerobic digestion of maize straw was investigated using mesophilic batch reactors. Three straw treatments were investigated as follows: NaOH (4% and 6%) pretreatment, Fe dosage (50, 200, 1000 and 2000 mg/L), and combined NaOH pretreatment and Fe dosage. Compared to the control, NaOH pretreatment alone increased methane yield by 3.5% (313.3 mL CH_4/gVS) and 22.5% (370.9 mL CH_4/gVS) and shortened the technical digestion time (TDT) from 48 days to 19 days and 10 days in 4% NaOH and 6% NaOH pretreatment respectively. Moreover, Fe dosing (200–1000 mg/L) alone gave a methane yield higher (9.4%) than that obtained from 4% NaOH and 7.5% less than the methane yield from 6% NaOH pretreatment; however, the TDT was 10 days longer. Combining NaOH pretreatment and Fe dosage (200–1000 mg/L) significantly increased the methane yield even further to 21.8% (368.8 mL CH_4/gVS) and 56.2% (472.9 mL CH_4/gVS), and shortened TDT from 48 days to 13 days and 7 days in 4% NaOH and 6% NaOH pretreatment respectively. This synergistic effect may be attributed to the fact that the alkaline treatment improved accessibility of the biodegradable fraction of the straw while Fe contributed to increased microbial enzyme activity.

Hydrothermal and alkaline hydrothermal pretreatments plus anaerobic digestion of sewage sludge for dewatering and biogas production: Bench-scale research and pilot-scale verification.

Science.gov (United States)

Li, Chunxing; Wang, Xingdong; Zhang, Guangyi; Yu, Guangwei; Lin, Jingjiang; Wang, Yin

2017-06-15

To test the feasibility and practicability of the process combing hydrothermal pretreatment for dewatering with biogas production for full utilization of sewage sludge, hydrothermal/alkaline hydrothermal pretreatments and in turn anaerobic digestion of the filtrates obtained after dewatering the pretreated sludge were performed at bench- and pilot-scales. The hydrothermal temperature fell within the range of 140 °C-220 °C and the pretreatment time varied from 30 min to 120 min. For the alkaline hydrothermal pretreatment the pH value of the sludge was adjusted to 9.0-11.0 by adding Ca(OH) 2 . The results showed that the dewaterability of the sewage sludge was improved with increasing pretreatment temperature but the impact of the pretreatment time was not significant. The addition of Ca(OH) 2 gave better performance on the subsequent mechanical dewatering of the pretreated sludge compared to pure hydrothermal pretreatment, and the higher the pH value was, the better the dewaterability of the pretreated sludge was. The conditions of 180 °C/30 min and 160 °C/60 min/pH = 10.0 (for hydrothermal and alkaline hydrothermal pretreatments, respectively) resulted in relatively good results in the theoretical energy balance, which were verified in the pilot-scale tests. Based on the data from the pilot tests, the alkaline hydrothermal process realized self-sufficiency in energy at the cost of a proper amount of CaO. Copyright © 2017 Elsevier Ltd. All rights reserved.

The pressure effects on two-phase anaerobic digestion

International Nuclear Information System (INIS)

Chen, Yuling; Rößler, Benjamin; Zielonka, Simon; Lemmer, Andreas; Wonneberger, Anna-Maria; Jungbluth, Thomas

2014-01-01

Highlights: • The pressure effect on anaerobic digestion up to 9 bar was examined. • Increasing pressure decreased pH value in the anaerobic filter. • Increasing pressure increased methane content. • Increasing pressure decreased specific methane yield slightly. • The pressurized methane reactor was very stable and performed well. - Abstract: Two-phase pressurized anaerobic digestion is a novel process aimed at facilitating injection of the produced biogas into the natural gas grid by integrating the fermentative biogas production and upgrading it to substitute natural gas. In order to understand the mechanisms, knowledge of pressure effects on anaerobic digestion is required. To examine the effects of pressure on the anaerobic digestion process, a two-phase anaerobic digestion system was built up in laboratory scale, including three acidogenesis-leach-bed-reactors and one pressure-resistant anaerobic filter. Four different pressure levels (the absolute pressure of 1 bar, 3 bar, 6 bar and 9 bar) were applied to the methane reactor in sequence, with the organic loading rate maintained at approximately 5.1 kgCOD m −3 d −1 . Gas production, gas quality, pH value, volatile fatty acids, alcohol, ammonium-nitrogen, chemical oxygen demand (COD) and alkaline buffer capacity were analyzed. No additional caustic chemicals were added for pH adjustment throughout the experiment. With the pressure increasing from 1.07 bar to 8.91 bar, the pH value decreased from 7.2 to 6.5, the methane content increased from 66% to 75%, and the specific methane yield was slightly reduced from 0.33 l N g −1 COD to 0.31 l N g −1 COD. There was almost no acid-accumulation during the entire experiment. The average COD-degradation grade was always more than 93%, and the average alkaline buffering capacity (VFA/TIC ratio) did not exceed 0.2 at any pressure level. The anaerobic filter showed a very stable performance, regardless of the pressure variation

The influence of aerobic sludge retention time on anaerobic co ...

African Journals Online (AJOL)

ABR) and aerobic plug flow reactor (PFR) were operated aiming to minimize excess sludge output of the activated sludge process through coupled alkaline hydrolysis and anaerobic digestion. Variations in the effluent total chemical oxygen ...

Cassava Stillage Treatment by Thermophilic Anaerobic Continuously Stirred Tank Reactor (CSTR)

Science.gov (United States)

Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi

2010-11-01

This paper assesses the performance of a thermophilic anaerobic Continuously Stirred Tank Reactor (CSTR) in the treatment of cassava stillage under various organic loading rates (OLRs) without suspended solids (SS) separation. The reactor was seeded with mesophilic anaerobic granular sludge, and the OLR increased by increments to 13.80 kg COD/m3/d (HRT 5d) over 80 days. Total COD removal efficiency remained stable at 90%, with biogas production at 18 L/d (60% methane). Increase in the OLR to 19.30 kg COD/m3/d (HRT 3d), however, led to a decrease in TCOD removal efficiency to 79% due to accumulation of suspended solids and incomplete degradation after shortened retention time. Reactor performance subsequently increased after OLR reduction. Alkalinity, VFA and pH levels were not significantly affected by OLR variation, indicating that no additional alkaline or pH adjustment is required. More than half of the SS in the cassava stillage could be digested in the process when HRT was 5 days, which demonstrated the suitability of anaerobic treatment of cassava stillage without SS separation.

Anaerobic treatment of Tequila vinasses in a CSTR-type digester.

Science.gov (United States)

Méndez-Acosta, Hugo Oscar; Snell-Castro, Raúl; Alcaraz-González, Víctor; González-Alvarez, Víctor; Pelayo-Ortiz, Carlos

2010-06-01

Tequila industries in general produce great volumes of effluents with high pollutant loads, which are discharged (untreated or partially treated) into natural receivers, thus causing severe environmental problems. In this contribution, we propose an integrated system as a first step to comply with the Mexican ecological norms and stabilize the anaerobic treatment of Tequila vinasses with main design criteria: simple and easy operation, reduce operating time and associated costs (maintenance), integrated and compact design, minimal cost of set-up, start-up, monitoring and control. This system is composed of a fully instrumented and automated lab-scale CSTR-type digester, on-line measuring devices of key variables (pH, temperature, flow rates, etc.), which are used along with off-line readings of chemical oxygen demand (COD), biogas composition, alkalinity and volatile fatty acids to guarantee the operational stability of the anaerobic digestion process. The system performance was evaluated for 200 days and the experimental results show that even under the influence of load disturbances, it is possible to reduce the COD concentration to 85% in the start-up phase and up to 95% during the normal operation phase while producing a biogas with a methane composition greater than 65%. It is also shown that in order to maintain an efficient treatment, the buffering capacity (given by the alkalinity ratio, alpha = intermediate alkalinity/total alkalinity) must be closely monitored.

Anaerobic Digestion Analysis. Training Module 5.120.2.77.

Science.gov (United States)

Kirkwood Community Coll., Cedar Rapids, IA.

This document is an instructional module package prepared in objective form for use by an instructor familiar with alkalinity, volatile acids and carbon dioxide determinations for an anaerobic sludge digester. Included are objectives, instructor guides, student handouts and transparency masters. This module considers total and bicarbonate…

In situ detection of anaerobic alkane metabolites in subsurface environments

Directory of Open Access Journals (Sweden)

Lisa eGieg

2013-06-01

Full Text Available Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditions. Elucidating the pathways of anaerobic alkane metabolism has been of interest in order to understand how microbes can be used to remediate contaminated sites. Alkane activation primarily occurs by addition to fumarate, yielding alkylsuccinates, unique anaerobic metabolites that can be used to indicate in situ anaerobic alkane metabolism. These metabolites have been detected in hydrocarbon-contaminated shallow aquifers, offering strong evidence for intrinsic anaerobic bioremediation. Recently, studies have also revealed that alkylsuccinates are present in oil and coal seam production waters, indicating that anaerobic microbial communities can utilize alkanes in these deeper subsurface environments. In many crude oil reservoirs, the in situ anaerobic metabolism of hydrocarbons such as alkanes may be contibuting to modern-day detrimental effects such as oilfield souring, or may lead to more benefical technologies such as enhanced energy recovery from mature oilfields. In this review, we briefly describe the key metabolic pathways for anaerobic alkane (including n-alkanes, isoalkanes, and cyclic alkanes metabolism and highlight several field reports wherein alkylsuccinates have provided evidence for anaerobic in situ alkane metabolism in shallow and deep subsurface environments.

1.5 My benthic foraminiferal B/Ca record of carbonate chemistry in the deep Atlantic: Implications for ocean alkalinity and atmospheric CO2

Science.gov (United States)

Rosenthal, Y.; Sosdian, S. M.; Toggweiler, J. R.

2017-12-01

Most hypotheses to explain glacial-interglacial changes in atmospheric CO2 invoke shifts in ocean alkalinity explain roughly half the reduction in glacial CO2 via CaCO3 compensatory mechanism. It follows that changes in CaCO3 burial occur in response to an increase in deep ocean respired carbon content. To date our understanding of this process comes from benthic carbon isotope and %CaCO3 records. However, to understand the nature of the ocean's buffering capacity and its role in modulating pCO2, orbitally resolved reconstructions of the deep ocean carbonate system parameters are necessary. Here we present a 1.5 Myr orbitally resolved deep ocean calcite saturation record (ΔCO32-) derived from benthic foraminiferal B/Ca ratios in the North Atlantic. Glacial B/Ca values decline across the mid-Pleistocene transition (MPT) suggesting increased sequestration of carbon in the deep Atlantic. The magnitude, timing, and structure of deep Atlantic Ocean ΔCO32- and %CaCO3 cycles contrast with the small amplitude, anti-phased swings in IndoPacific ΔCO32- and %CaCO3 during the mid-to-late Pleistocene. Increasing corrosivity of the deep Atlantic causes the locus of CaCO3 burial to shift into the equatorial Pacific where the flux of CaCO3 to the seafloor is high enough to establish and maintain a new "hot spot". We propose that the CO32- in the deep IndoPacific rises in response to the same mechanism that keeps the CO32- in the deep Atlantic low and the atmospheric CO2 low. The increase in interglacial atmospheric pCO2 levels following the Mid-Brunhes event ( 400ka) are associated with increased G/IG ΔCO3 amplitude, expressed by a decrease in the glacial ΔCO32- values. We propose the low persistent ΔCO32- levels at Marine Isotope Stage (MIS) 12 set the stage for the high pCO2 levels at MIS 11 via an increase in whole ocean alkalinity followed by enhanced CaCO3 preservation. Based on this, we suggest that the development of classic (`anticorrelated') CaCO3 patterns was

Genomic analysis of Melioribacter roseus, facultatively anaerobic organotrophic bacterium representing a novel deep lineage within Bacteriodetes/Chlorobi group.

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Vitaly V Kadnikov

Full Text Available Melioribacter roseus is a moderately thermophilic facultatively anaerobic organotrophic bacterium representing a novel deep branch within Bacteriodetes/Chlorobi group. To better understand the metabolic capabilities and possible ecological functions of M. roseus and get insights into the evolutionary history of this bacterial lineage, we sequenced the genome of the type strain P3M-2(T. A total of 2838 open reading frames was predicted from its 3.30 Mb genome. The whole proteome analysis supported phylum-level classification of M. roseus since most of the predicted proteins had closest matches in Bacteriodetes, Proteobacteria, Chlorobi, Firmicutes and deeply-branching bacterium Caldithrix abyssi, rather than in one particular phylum. Consistent with the ability of the bacterium to grow on complex carbohydrates, the genome analysis revealed more than one hundred glycoside hydrolases, glycoside transferases, polysaccharide lyases and carbohydrate esterases. The reconstructed central metabolism revealed pathways enabling the fermentation of complex organic substrates, as well as their complete oxidation through aerobic and anaerobic respiration. Genes encoding the photosynthetic and nitrogen-fixation machinery of green sulfur bacteria, as well as key enzymes of autotrophic carbon fixation pathways, were not identified. The M. roseus genome supports its affiliation to a novel phylum Ignavibateriae, representing the first step on the evolutionary pathway from heterotrophic ancestors of Bacteriodetes/Chlorobi group towards anaerobic photoautotrophic Chlorobi.

Alkaline degradation of organic materials contained in TRU wastes under repository conditions

International Nuclear Information System (INIS)

Otsuka, Yoshiki; Banba, Tsunetaka

2007-09-01

Alkaline degradation tests for 9 organic materials were conducted under the conditions of TRU waste disposal: anaerobic alkaline conditions. The tests were carried out at 90degC for 91 days. The sample materials for the tests were selected from the standpoint of constituent organic materials of TRU wastes. It has been found that cellulose and plastic solidified products are degraded relatively easily and that rubbers are difficult to degrade. It could be presumed that the alkaline degradation of organic materials occurs starting from the functional group in the material. Therefore, the degree of degradation difficulty is expected to be dependent on the kinds of functional group contained in the organic material. (author)

A steady state model for anaerobic digestion of sewage sludges ...

African Journals Online (AJOL)

A steady state model for anaerobic digestion of sewage sludge is developed that comprises three sequential parts – a kinetic part from which the % COD removal and ... and a carbonate system weak acid/base chemistry part from which the digester pH is calculated from the partial pressure of CO2 and alkalinity generated.

Reduction of hexavalent chromium by Pannonibacter phragmitetus LSSE-09 stimulated with external electron donors under alkaline conditions

International Nuclear Information System (INIS)

Xu Lin; Luo Mingfang; Li Wangliang; Wei Xuetuan; Xie Keng; Liu Lijun; Jiang Chengying; Liu Huizhou

2011-01-01

Research highlights: → Growing cells have high Cr (VI) resistant and reducing ability aerobically. → Resting cells show strong anaerobic-reduction potential. → Acetate can highly stimulate both aerobic and anaerobic reduction process. - Abstract: A novel Cr (VI) resistant bacterial strain LSSE-09, identified as Pannonibacter phragmitetus, was isolated from industrial sludge. It has strong aerobic and anaerobic Cr (VI)-reduction potential under alkaline conditions. At 37 o C and pH 9.0, growing cells of strain LSSE-09 could completely reduce 100 and 1000 mg L -1 Cr (VI)-Cr (III) within 9 and 24 h, respectively under aerobic condition. Resting cells showed higher anaerobic reduction potential with the rate of 1.46 mg g -1 (dryweight) min -1 , comparing with their aerobic reduction rate, 0.21 mg g -1 min -1 . External electron donors, such as lactate, acetate, formate, pyruvate, citrate and glucose could highly increase the reduction rate, especially for aerobic reduction. The presence of 3000 mg L -1 acetate enhanced anaerobic and aerobic Cr (VI)-reduction rates up to 9.47 mg g -1 min -1 and 4.42 mg g -1 min -1 , respectively, which were 5 and 20 times faster than those without it. Strain LSSE-09 retained high activities over six batch cycles and NO 3 - and SO 4 2- had slightly negative effects on Cr (VI)-reduction rates. The results suggest that strain LSSE-09 has potential application for Cr (VI) detoxification in alkaline wastewater.

Evaluation of the 5 and 8 pH point titration methods for monitoring anaerobic digesters treating solid waste.

Science.gov (United States)

Vannecke, T P W; Lampens, D R A; Ekama, G A; Volcke, E I P

2015-01-01

Simple titration methods certainly deserve consideration for on-site routine monitoring of volatile fatty acid (VFA) concentration and alkalinity during anaerobic digestion (AD), because of their simplicity, speed and cost-effectiveness. In this study, the 5 and 8 pH point titration methods for measuring the VFA concentration and carbonate system alkalinity (H2CO3*-alkalinity) were assessed and compared. For this purpose, synthetic solutions with known H2CO3*-alkalinity and VFA concentration as well as samples from anaerobic digesters treating three different kind of solid wastes were analysed. The results of these two related titration methods were verified with photometric and high-pressure liquid chromatography measurements. It was shown that photometric measurements lead to overestimations of the VFA concentration in the case of coloured samples. In contrast, the 5 pH point titration method provides an accurate estimation of the VFA concentration, clearly corresponding with the true value. Concerning the H2CO3*-alkalinity, the most accurate and precise estimations, showing very similar results for repeated measurements, were obtained using the 8 pH point titration. Overall, it was concluded that the 5 pH point titration method is the preferred method for the practical monitoring of AD of solid wastes due to its robustness, cost efficiency and user-friendliness.

Biologic treatment of wastewater from cassava flour production using vertical anaerobic baffled reactor (VABR

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Gleyce T Correia

2008-08-01

Full Text Available The estimate cassava production in Brazil in 2007 was of 25 million tons (= 15% of the world production and most of it is used in the production of flour. During its processing, waste that can cause environmental inequality is generated, if discharged inappropriately. One of the liquid waste generated, manipueira, is characterized by its high level of organic matter. The anaerobic treatment that uses a vertical anaerobic baffled reactor (VABR inoculated with granulated sludge, is one of the ways of treating this effluent. The anaerobic biodigestion phases are separated in this kind of reactor, allowing greater stability and resistance to load shocks. The VABR was built with a width/height rate of 1:2. The pH, acidity, alkalinity, turbidity and COD removal were analyzed in 6 different regions of the reactor, which was operated with an increasing feeding from ? 2000 to ? 10000 mg COD L?¹ and HRT between 6.0 and 2.5 days. The VABR showed decreasing acidity and turbidity, an increase in alkalinity and pH, and 96% efficiency in COD removal with 3-day HRT and feeding of 3800 mg COD L?¹.

Treatment of municipal landfill leachate using a combined anaerobic digester and activated sludge system

International Nuclear Information System (INIS)

Kheradmand, S.; Karimi-Jashni, A.; Sartaj, M.

2010-01-01

The main objective of this study was to assess the feasibility of treating sanitary landfill leachate using a combined anaerobic and activated sludge system. A high-strength leachate from Shiraz municipal landfill site was treated using this system. A two-stage laboratory-scale anaerobic digester under mesophilic conditions and an activated sludge unit were used. Landfill leachate composition and characteristics varied considerably during 8 months experiment (COD concentrations of 48,552-62,150 mg/L). It was found that the system could reduce the COD of the leachate by 94% at a loading rate of 2.25 g COD/L/d and 93% at loading rate of 3.37 g COD/L/d. The anaerobic digester treatment was quite effective in removing Fe, Cu, Mn, and Ni. However, in the case of Zn, removal efficiency was about 50%. For the rest of the HMs the removal efficiencies were in the range 88.8-99.9%. Ammonia reduction did not occur in anaerobic digesters. Anaerobic reactors increased alkalinity about 3.2-4.8% in the 1st digester and 1.8-7.9% in the 2nd digester. In activated sludge unit, alkalinity and ammonia removal efficiency were 49-60% and 48.6-64.7%, respectively. Methane production rate was in the range of 0.02-0.04, 0.04-0.07, and 0.02-0.04 L/g COD rem for the 1st digester, the 2nd digester, and combination of both digesters, respectively; the methane content of the biogas varied between 60% and 63%.

Anaerobic methanotrophic communities thrive in deep submarine permafrost.

Science.gov (United States)

Winkel, Matthias; Mitzscherling, Julia; Overduin, Pier P; Horn, Fabian; Winterfeld, Maria; Rijkers, Ruud; Grigoriev, Mikhail N; Knoblauch, Christian; Mangelsdorf, Kai; Wagner, Dirk; Liebner, Susanne

2018-01-22

Thawing submarine permafrost is a source of methane to the subsurface biosphere. Methane oxidation in submarine permafrost sediments has been proposed, but the responsible microorganisms remain uncharacterized. We analyzed archaeal communities and identified distinct anaerobic methanotrophic assemblages of marine and terrestrial origin (ANME-2a/b, ANME-2d) both in frozen and completely thawed submarine permafrost sediments. Besides archaea potentially involved in anaerobic oxidation of methane (AOM) we found a large diversity of archaea mainly belonging to Bathyarchaeota, Thaumarchaeota, and Euryarchaeota. Methane concentrations and δ 13 C-methane signatures distinguish horizons of potential AOM coupled either to sulfate reduction in a sulfate-methane transition zone (SMTZ) or to the reduction of other electron acceptors, such as iron, manganese or nitrate. Analysis of functional marker genes (mcrA) and fluorescence in situ hybridization (FISH) corroborate potential activity of AOM communities in submarine permafrost sediments at low temperatures. Modeled potential AOM consumes 72-100% of submarine permafrost methane and up to 1.2 Tg of carbon per year for the total expected area of submarine permafrost. This is comparable with AOM habitats such as cold seeps. We thus propose that AOM is active where submarine permafrost thaws, which should be included in global methane budgets.

Physiologically anaerobic microorganisms of the deep subsurface. Progress report, June 1, 1990--May 30, 1991

Energy Technology Data Exchange (ETDEWEB)

Stevens, S.E. Jr.; Chung, K.T.

1991-06-01

This study seeks to determine numbers, diversity, and morphology of anaerobic microorganisms in 15 samples of subsurface material from the Idaho National Engineering Laboratory, in 18 samples from the Hanford Reservation and in 1 rock sample from the Nevada Test Site; set up long term experiments on the chemical activities of anaerobic microorganisms based on these same samples; work to improve methods for the micro-scale determination of in situ anaerobic microbial activity;and to begin to isolate anaerobes from these samples into axenic culture with identification of the axenic isolates.

Thermophilic Alkaline Fermentation Followed by Mesophilic Anaerobic Digestion for Efficient Hydrogen and Methane Production from Waste-Activated Sludge: Dynamics of Bacterial Pathogens as Revealed by the Combination of Metagenomic and Quantitative PCR Analyses.

Science.gov (United States)

Wan, Jingjing; Jing, Yuhang; Rao, Yue; Zhang, Shicheng; Luo, Gang

2018-03-15

Thermophilic alkaline fermentation followed by mesophilic anaerobic digestion (TM) for hydrogen and methane production from waste-activated sludge (WAS) was investigated. The TM process was also compared to a process with mesophilic alkaline fermentation followed by a mesophilic anaerobic digestion (MM) and one-stage mesophilic anaerobic digestion (M) process. The results showed that both hydrogen yield (74.5 ml H 2 /g volatile solids [VS]) and methane yield (150.7 ml CH 4 /g VS) in the TM process were higher than those (6.7 ml H 2 /g VS and 127.8 ml CH 4 /g VS, respectively) in the MM process. The lowest methane yield (101.2 ml CH 4 /g VS) was obtained with the M process. Taxonomic results obtained from metagenomic analysis showed that different microbial community compositions were established in the hydrogen reactors of the TM and MM processes, which also significantly changed the microbial community compositions in the following methane reactors compared to that with the M process. The dynamics of bacterial pathogens were also evaluated. For the TM process, the reduced diversity and total abundance of bacterial pathogens in WAS were observed in the hydrogen reactor and were further reduced in the methane reactor, as revealed by metagenomic analysis. The results also showed not all bacterial pathogens were reduced in the reactors. For example, Collinsella aerofaciens was enriched in the hydrogen reactor, which was also confirmed by quantitative PCR (qPCR) analysis. The study further showed that qPCR was more sensitive for detecting bacterial pathogens than metagenomic analysis. Although there were some differences in the relative abundances of bacterial pathogens calculated by metagenomic and qPCR approaches, both approaches demonstrated that the TM process was more efficient for the removal of bacterial pathogens than the MM and M processes. IMPORTANCE This study developed an efficient process for bioenergy (H 2 and CH 4 ) production from WAS and elucidates the

Methane Seep in Shallow-Water Permeable Sediment Harbors High Diversity of Anaerobic Methanotrophic Communities, Elba, Italy

Science.gov (United States)

Ruff, S. Emil; Kuhfuss, Hanna; Wegener, Gunter; Lott, Christian; Ramette, Alban; Wiedling, Johanna; Knittel, Katrin; Weber, Miriam

2016-01-01

The anaerobic oxidation of methane (AOM) is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB), and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic carbon depleted permeable sands off the Island of Elba (Italy). We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g-1 day-1 indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20–50 cm below seafloor) as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3, and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise distinct

Methane Seep in Shallow-Water Permeable Sediment Harbors High Diversity of Anaerobic Methanotrophic Communities, Elba, Italy.

Science.gov (United States)

Ruff, S Emil; Kuhfuss, Hanna; Wegener, Gunter; Lott, Christian; Ramette, Alban; Wiedling, Johanna; Knittel, Katrin; Weber, Miriam

2016-01-01

The anaerobic oxidation of methane (AOM) is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB), and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic carbon depleted permeable sands off the Island of Elba (Italy). We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g(-1) day(-1) indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20-50 cm below seafloor) as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3, and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise distinct

Pretreatment of wheat straw and conversion of xylose and xylan to ethanol by thermophilic anaerobic bacteria

DEFF Research Database (Denmark)

Ahring, Birgitte Kiær; Jensen, K.; Nielsen, P.

1996-01-01

solubilization was investigated. The two process parameters had little effect on the solubilization of hemicellulose. However alkaline conditions affected the furfural formation whereas oxygen had no effect. After pretreatment, the filtrate was used as a fermentation medium for thermophilic anaerobic bacterin...

Effect of alkaline pretreatment on mesophilic and thermophilic anaerobic digestion of a submerged macrophyte: Inhibition and recovery against dissolved lignin during semi-continuous operation.

Science.gov (United States)

Koyama, Mitsuhiko; Watanabe, Keiko; Kurosawa, Norio; Ishikawa, Kanako; Ban, Syuhei; Toda, Tatsuki

2017-08-01

The long-term effect of alkaline pretreatment on semi-continuous anaerobic digestion (AD) of the lignin-rich submerged macrophyte Potamogeton maackianus was investigated using mesophilic and thermophilic conditions. In pretreated reactors, dissolved lignin accumulated to high levels. CH 4 production under the pretreated condition was higher than that of the untreated condition, but decreased from Days 22 (mesophilic) and 42 (thermophilic). However, CH 4 production subsequently recovered, although dissolved lignin accumulated. Further, the change in the microbial community was observed between conditions. These results suggest that dissolved lignin temporarily inhibited AD, although acclimatization to dissolved lignin occurred during long-term operation. During the steady state period, mesophilic conditions achieved a 42% increase in the CH 4 yield using pretreatment, while thermophilic conditions yielded an 8% increment. Because volatile fatty acids accumulated even after acclimatization during the thermophilic pretreated condition and was discharged with the effluent, improvement of the methanogenic step would enable enhanced CH 4 recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

EFFECTS OF ALKALINE SANDY LOAM ON SULFURIC SOIL ACIDITY AND SULFIDIC SOIL OXIDATION

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Patrick S. Michael

2015-08-01

Full Text Available  In poor soils, addition of alkaline sandy loam containing an adequate proportion of sand, silt and clay would add value by improving the texture, structure and organic matter (OM for general use of the soils. In acid sulfate soils (ASS, addition of alkaline sandy would improve the texture and leach out salts as well as add a sufficient proportion of OM for vegetation establishment. In this study, addition of alkaline sandy loam into sulfuric soil effectively increased the pH, lowered the redox and reduced the sulfate content, the magnitude of the effects dependent on moisture content. Addition of alkaline sandy loam in combination with OM was highly effective than the effects of the lone alkaline sandy loam. When alkaline sandy was added alone or in combination with OM into sulfidic soil, the effects on pH and the redox were similar as in the sulfuric soil but the effect on sulfate content was variable. The effects under aerobic conditions were higher than under anaerobic conditions. The findings of this study have important implications for the general management of ASS where lime availability is a concern and its application is limited.International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 42-54

Alkalinity production in intertidal sands intensified by lugworm bioirrigation

NARCIS (Netherlands)

Rao, A.M.F.; Malkin, S.Y.; Montserrat, F; Meysman, F.J.R.

2014-01-01

Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete

Recovery of ammonia from anaerobically digested manure using gas-permeable membranes

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Maria Cruz García-González

Full Text Available ABSTRACT Nitrogen (N can be recovered from different types of wastewaters. Among these wastewaters, anaerobically digested swine manure (digestate has the highest N content in ammonia form (NH3. It is desirable to reduce N in digestate effluents to safely incorporate them in arable soil in N vulnerable zones (NVZ and to mitigate NH3 emissions during N land application. Additional benefit is to minimize inhibition of the anaerobic process by removing NH3 during the anaerobic digestion process. This work aimed to apply the gas-permeable membrane technology to evaluate ammonia (NH3 recovery from high-ammonia digested swine manure. Anaerobically digested swine manure with NH4+ content of 4,293 mg N L−1 was reduced by 91 % (to 381 mg N L−1 during the 32-day experiment. Although the results showed a total N recovery efficiency of 71 %, it is possible to increase this recovery efficiency to > 90 % by adjusting the area of the membrane system to match the high free ammonia concentration (FA in digested swine manure. Moreover, final digestate pH and alkalinity were kept around 8.1 and 8,923 mgCaCO3 L−1, which are convenient for the anaerobic process or incorporation in arable soil when the process is finished.

Gene expression in the deep biosphere.

Science.gov (United States)

Orsi, William D; Edgcomb, Virginia P; Christman, Glenn D; Biddle, Jennifer F

2013-07-11

Scientific ocean drilling has revealed a deep biosphere of widespread microbial life in sub-seafloor sediment. Microbial metabolism in the marine subsurface probably has an important role in global biogeochemical cycles, but deep biosphere activities are not well understood. Here we describe and analyse the first sub-seafloor metatranscriptomes from anaerobic Peru Margin sediment up to 159 metres below the sea floor, represented by over 1 billion complementary DNA (cDNA) sequence reads. Anaerobic metabolism of amino acids, carbohydrates and lipids seem to be the dominant metabolic processes, and profiles of dissimilatory sulfite reductase (dsr) transcripts are consistent with pore-water sulphate concentration profiles. Moreover, transcripts involved in cell division increase as a function of microbial cell concentration, indicating that increases in sub-seafloor microbial abundance are a function of cell division across all three domains of life. These data support calculations and models of sub-seafloor microbial metabolism and represent the first holistic picture of deep biosphere activities.

Isolation and characterization of Caldicellulosiruptor lactoaceticus sp. nov., an extremely thermophilic, cellulolytic, anaerobic bacterium

DEFF Research Database (Denmark)

Mladenovska, Zuzana; Mathrani, Indra M.; Ahring, Birgitte Kiær

1995-01-01

An anaerobic, extremely thermophilic, cellulolytic, non-spore-forming bacterium, strain 6A, was isolated from an alkaline hot spring in Hverageroi, Iceland. The bacterium was non-motile, rod-shaped (1.5-3.5 x 0.7 mu m) and occurred singly, in pairs or in chains and stained gram-negative. The growth...

Anaerobic animals from an ancient, anoxic ecological niche

Directory of Open Access Journals (Sweden)

Martin William

2010-04-01

Full Text Available Abstract Tiny marine animals that complete their life cycle in the total absence of light and oxygen are reported by Roberto Danovaro and colleagues in this issue of BMC Biology. These fascinating animals are new members of the phylum Loricifera and possess mitochondria that in electron micrographs look very much like hydrogenosomes, the H2-producing mitochondria found among several unicellular eukaryotic lineages. The discovery of metazoan life in a permanently anoxic and sulphidic environment provides a glimpse of what a good part of Earth's past ecology might have been like in 'Canfield oceans', before the rise of deep marine oxygen levels and the appearance of the first large animals in the fossil record roughly 550-600 million years ago. The findings underscore the evolutionary significance of anaerobic deep sea environments and the anaerobic lifestyle among mitochondrion-bearing cells. They also testify that a fuller understanding of eukaryotic and metazoan evolution will come from the study of modern anoxic and hypoxic habitats.

Millennia of magmatism recorded in crustal xenoliths from alkaline provinces in Southwest Greenland

DEFF Research Database (Denmark)

Smit, Matthijs; Waight, Tod Earle; Nielsen, Troels

2016-01-01

Neoproterozoic alkaline provinces in West Greenland: 1)Sarfartôq, which overlies Archean ultra-depleted SCLM and yielded ultra-deep mineral indicators, and 2)Sisimiut, where the SCLM is refertilized and deep xenoliths (>120km) are lacking. We focused on the rare and understudied crustal xenoliths, which preserve...

Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake

Science.gov (United States)

Deutzmann, Joerg S.; Stief, Peter; Brandes, Josephin; Schink, Bernhard

2014-01-01

Anaerobic methane oxidation coupled to denitrification, also known as “nitrate/nitrite-dependent anaerobic methane oxidation” (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were very abundant at deep-water sites (profundal sediment). In profundal sediment, the vertical distribution of M. oxyfera-like bacteria showed a distinct peak in anoxic layers that coincided with the zone of methane oxidation and nitrate consumption, a strong indication for n-damo carried out by M. oxyfera-like bacteria. Both potential n-damo rates calculated from cell densities (660–4,890 µmol CH4⋅m−2⋅d−1) and actual rates calculated from microsensor profiles (31–437 µmol CH4⋅m−2⋅d−1) were sufficiently high to prevent methane release from profundal sediment solely by this process. Additionally, when nitrate was added to sediment cores exposed to anoxic conditions, the n-damo zone reestablished well below the sediment surface, completely preventing methane release from the sediment. We conclude that the previously overlooked n-damo process can be the major methane sink in stable freshwater environments if nitrate is available in anoxic zones. PMID:25472842

Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake.

Science.gov (United States)

Deutzmann, Joerg S; Stief, Peter; Brandes, Josephin; Schink, Bernhard

2014-12-23

Anaerobic methane oxidation coupled to denitrification, also known as "nitrate/nitrite-dependent anaerobic methane oxidation" (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were very abundant at deep-water sites (profundal sediment). In profundal sediment, the vertical distribution of M. oxyfera-like bacteria showed a distinct peak in anoxic layers that coincided with the zone of methane oxidation and nitrate consumption, a strong indication for n-damo carried out by M. oxyfera-like bacteria. Both potential n-damo rates calculated from cell densities (660-4,890 µmol CH4⋅m(-2)⋅d(-1)) and actual rates calculated from microsensor profiles (31-437 µmol CH4⋅m(-2)⋅d(-1)) were sufficiently high to prevent methane release from profundal sediment solely by this process. Additionally, when nitrate was added to sediment cores exposed to anoxic conditions, the n-damo zone reestablished well below the sediment surface, completely preventing methane release from the sediment. We conclude that the previously overlooked n-damo process can be the major methane sink in stable freshwater environments if nitrate is available in anoxic zones.

Combination of alkaline and microwave pretreatment for disintegration of meat processing wastewater sludge.

Science.gov (United States)

Erden, G

2013-01-01

Meat processing wastewater sludge has high organic content but it is very slow to degrade in biological processes. Anaerobic digestion may be a good alternative for this type of sludge when the hydrolysis, known to be the rate-limiting step of biological sludge anaerobic degradation, could be eliminated by disintegration. This investigation deals with disintegration of meat processing wastewater sludge. Microwave (MW) irradiation and combined alkaline pretreatment and MW irradiation were applied to sludge for disintegration purposes. Disintegration performance of the methods was evaluated with disintegration degree based on total and dissolved organic carbon calculations (DD(TOC)), and the solubilization of volatile solids (S(VS)) in the pretreated sludge. Optimum conditions were found to be 140 degrees C and 30 min for MW irradiation using response surface methodology (RSM) and pH = 13 for combined pretreatment. While DD(TOC) was observed as 24.6% and 54.9, S(VS) was determined as 8.54% and 42.5% for MW pretreated and combined pretreated sludge, respectively. The results clearly show that pre-conditioning of sludge with alkaline pretreatment played an important role in enhancing the disintegration efficiency of subsequent MW irradiation. Disintegration methods also affected the anaerobic biodegradability and dewaterability of sludge. An increase of 23.6% in biogas production in MW irradiated sludge was obtained, comparing to the raw sludge at the end of the 35 days of incubation. This increase was observed as 44.5% combined pretreatment application. While MW pretreatment led to a little improvement of the dewatering performance of sludge, in combined pretreatment NaOH deteriorates the sludge dewaterability.

Anaerobic digestion of thin stillage for energy recovery and water reuse in corn-ethanol plants.

Science.gov (United States)

Alkan-Ozkaynak, A; Karthikeyan, K G

2011-11-01

Recycling of anaerobically-digested thin stillage within a corn-ethanol plant may result in the accumulation of nutrients of environmental concern in animal feed coproducts and inhibitory organic materials in the fermentation tank. Our focus is on anaerobic digestion of treated (centrifugation and lime addition) thin stillage. Suitability of digestate from anaerobic treatment for reuse as process water was also investigated. Experiments conducted at various inoculum-to-substrate ratios (ISRs) revealed that alkalinity is a critical parameter limiting digestibility of thin stillage. An ISR level of 2 appeared optimal based on high biogas production level (763 mL biogas/g volatile solids added) and organic matter removal (80.6% COD removal). The digester supernatant at this ISR level was found to contain both organic and inorganic constituents at levels that would cause no inhibition to ethanol fermentation. Anaerobic digestion of treated-thin stillage can be expected to improve the water and energy efficiencies of dry grind corn-ethanol plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Development of low alkaline cementitious grouting materials for a deep geological repository

International Nuclear Information System (INIS)

Suzuki, Kenichiro; Miura, Norihiko; Iriya, Keishiro; Kobayashi, Yasushi

2012-01-01

In order to reduce uncertainties of long-term safety assessment for a High Level radioactive Waste (HLW) repository system, low alkaline cementitious grouting materials have been studied. The pH of the leachate from the grouting material is targeted to be below 11.0, since the degradation of the bentonite buffer and host rock is limited. The current work focused on the effects of pozzolanic reactions to reduce pH and the development of low alkaline cementitious injection materials in which super-micro ordinary Portland cement (SOPC) was partially replaced by silica fume (SF), micro silica (MS) and fly ash (FA). As it is important to realize how the grouting material will respond to a high injection pressure into the fracture, and in order to understand the penetrability of different low alkaline cement mixes and to observe their flow behavior through the fracture, injection tests were conducted by using a simulated model fracture of 2 m diameter made from parallel plates of acrylic acid resin and stainless steel. Experimental results of the basic properties for selecting suitable materials and that of injecting into a simulated fracture to assess the grouting performance are described

Influence of leachate recirculation on aerobic and anaerobic decomposition of solid wastes

International Nuclear Information System (INIS)

Bilgili, M. Sinan; Demir, Ahmet; Ozkaya, Bestamin

2007-01-01

In this study, the effect of leachate recirculation on aerobic and anaerobic degradation of municipal solid wastes is determined by four laboratory-scale landfill reactors. The options studied and compared with the traditional anaerobic landfill are: leachate recirculation, landfill aeration, and aeration with leachate recirculation. Leachate quality is regularly monitored by the means of pH, alkalinity, total dissolved solids, conductivity, oxidation-reduction potential, chloride, chemical oxygen demand, ammonia, and total Kjeldahl nitrogen, in addition to generated leachate quantity. Aerobic leachate recirculated landfill appears to be the most effective option in the removal of organic matter and ammonia. The main difference between aerobic recirculated and non-recirculated landfill options is determined at leachate quantity. Recirculation is more effective on anaerobic degradation of solid waste than aerobic degradation. Further studies are going on to determine the optimum operational conditions for aeration and leachate recirculation rates, also with the operational costs of aeration and recirculation

Illumina sequencing-based analysis of a microbial community enriched under anaerobic methane oxidation condition coupled to denitrification revealed coexistence of aerobic and anaerobic methanotrophs.

Science.gov (United States)

Siniscalchi, Luciene Alves Batista; Leite, Laura Rabelo; Oliveira, Guilherme; Chernicharo, Carlos Augusto Lemos; de Araújo, Juliana Calabria

2017-07-01

Methane is produced in anaerobic environments, such as reactors used to treat wastewaters, and can be consumed by methanotrophs. The composition and structure of a microbial community enriched from anaerobic sewage sludge under methane-oxidation condition coupled to denitrification were investigated. Denaturing gradient gel electrophoresis (DGGE) analysis retrieved sequences of Methylocaldum and Chloroflexi. Deep sequencing analysis revealed a complex community that changed over time and was affected by methane concentration. Methylocaldum (8.2%), Methylosinus (2.3%), Methylomonas (0.02%), Methylacidiphilales (0.45%), Nitrospirales (0.18%), and Methanosarcinales (0.3%) were detected. Despite denitrifying conditions provided, Nitrospirales and Methanosarcinales, known to perform anaerobic methane oxidation coupled to denitrification (DAMO) process, were in very low abundance. Results demonstrated that aerobic and anaerobic methanotrophs coexisted in the reactor together with heterotrophic microorganisms, suggesting that a diverse microbial community was important to sustain methanotrophic activity. The methanogenic sludge was a good inoculum to enrich methanotrophs, and cultivation conditions play a selective role in determining community composition.

Methane seep in shallow-water permeable sediment harbors high diversity of anaerobic methanotrophic communities, Elba, Italy

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S Emil Ruff

2016-03-01

Full Text Available The anaerobic oxidation of methane (AOM is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME and sulfate-reducing bacteria (SRB, and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic-carbon depleted permeable sands off the Island of Elba (Italy. We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g-1 day-1 indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20–50 cm below seafloor as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3 and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise

Assessment of the ability of sludge to degrade PCP under anaerobic conditions

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R. M. L. Bolaños

2005-12-01

Full Text Available The capacity of sludge from different sources to degrade pentachlorophenol (PCP was evaluated. Three 2.5 liter reactors (R1, R2, and R3 were inoculated with different anaerobic sludges, semi continuously fed and maintained in orbital motion at 30±1°C. R1 was inoculated with aerobic sludge and river sediment collected downstream from a pulp and paper plant. R2 received sludge from an anaerobic reactor treating effluents from a paper recycling plant and R3 received anaerobic sludge from a biodigestor treating industrial and domestic effluents. The sludges were first acclimatized to a culture medium generally recommended for organochloride anaerobic degradation studies. The reactors were then subjected to increasing concentrations of PCP from 0.05 to 10.0 mg.l-1. PCP degradation and metabolite formation were monitored using gas chromatography, and the effects of PCP on the anaerobic process were verified by monitoring pH, volatile fatty acids, alkalinity, total suspended solids, and chemical oxygen demand. It was found that PCP did not affect reactor performance. All the sludges displayed the best PCP degradation capacity at a concentration of 0.2 mg.l-1, producing fewer chlorinated metabolites than when higher PCP concentrations were applied. R1 consistently produced fewer chlorinated metabolites, confirming the hypothesis that pre exposure to chlorinated compounds improves the sludge's capacity to degrade PCP.

New thermophilic anaerobes that decompose crystalline cellulose

Energy Technology Data Exchange (ETDEWEB)

Taya, M; Hinoki, H; Suzuki, Y; Yagi, T; Yap, M G.S.; Kobayashi, T

1985-01-01

Two strains (designated as 25A and 3B) of cellulolytic, thermophilic, anaerobic, spore-forming bacteria were newly isolated from an alkaline hot spring through enrichment cultures at 60/sup 0/C. Though strain 25A was nearly identical to Clostridium thermocellum ATCC 27405 as a reference strain, strain 3B had some characteristics different from the reference; no flagellation, alkalophilic growth property (optimum pH of 7.5-8) and orange-colored pigmentation of the cell mass. Strain 3B effectively decomposed micro-crystalline cellulose (Avicel) and raw cellulosics (rice straw, newspaper, and bagasse) without physical or chemical pretreatments. 20 references, 2 figures, 2 tables.

Identification and characterization of miRNAs and targets in flax (Linum usitatissimum) under saline, alkaline, and saline-alkaline stresses.

Science.gov (United States)

Yu, Ying; Wu, Guangwen; Yuan, Hongmei; Cheng, Lili; Zhao, Dongsheng; Huang, Wengong; Zhang, Shuquan; Zhang, Liguo; Chen, Hongyu; Zhang, Jian; Guan, Fengzhi

2016-05-27

MicroRNAs (miRNAs) play a critical role in responses to biotic and abiotic stress and have been characterized in a large number of plant species. Although flax (Linum usitatissimum L.) is one of the most important fiber and oil crops worldwide, no reports have been published describing flax miRNAs (Lus-miRNAs) induced in response to saline, alkaline, and saline-alkaline stresses. In this work, combined small RNA and degradome deep sequencing was used to analyze flax libraries constructed after alkaline-salt stress (AS2), neutral salt stress (NSS), alkaline stress (AS), and the non-stressed control (CK). From the CK, AS, AS2, and NSS libraries, a total of 118, 119, 122, and 120 known Lus-miRNAs and 233, 213, 211, and 212 novel Lus-miRNAs were isolated, respectively. After assessment of differential expression profiles, 17 known Lus-miRNAs and 36 novel Lus-miRNAs were selected and used to predict putative target genes. Gene ontology term enrichment analysis revealed target genes that were involved in responses to stimuli, including signaling and catalytic activity. Eight Lus-miRNAs were selected for analysis using qRT-PCR to confirm the accuracy and reliability of the miRNA-seq results. The qRT-PCR results showed that changes in stress-induced expression profiles of these miRNAs mirrored expression trends observed using miRNA-seq. Degradome sequencing and transcriptome profiling showed that expression of 29 miRNA-target pairs displayed inverse expression patterns under saline, alkaline, and saline-alkaline stresses. From the target prediction analysis, the miR398a-targeted gene codes for a copper/zinc superoxide dismutase, and the miR530 has been shown to explicitly target WRKY family transcription factors, which suggesting that these two micRNAs and their targets may significant involve in the saline, alkaline, and saline-alkaline stress response in flax. Identification and characterization of flax miRNAs, their target genes, functional annotations, and gene

Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

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Suschka Jan

2014-07-01

Full Text Available Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

Effects of lipid concentration on anaerobic co-digestion of municipal biomass wastes

International Nuclear Information System (INIS)

Sun, Yifei; Wang, Dian; Yan, Jiao; Qiao, Wei; Wang, Wei; Zhu, Tianle

2014-01-01

Highlights: • Lipid in municipal biomass would not inhibited the anaerobic digestion process. • A lipid concentration of 65% of total VS was the inhibition concentration. • The amount of Brevibacterium decreased with the increasing of the lipid contents. • Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process. - Abstract: The influence of the lipid concentration on the anaerobic co-digestion of municipal biomass waste and waste-activated sludge was assessed by biochemical methane potential (BMP) tests and by bench-scale tests in a mesophilic semi-continuous stirred tank reactor. The effect of increasing the volatile solid (VS) concentration of lipid from 0% to 75% was investigated. BMP tests showed that lipids in municipal biomass waste could enhance the methane production. The results of bench-scale tests showed that a lipids concentration of 65% of total VS was the inhibition concentration. Methane yields increased with increasing lipid concentration when lipid concentrations were below 60%, but when lipid concentration was set as 65% or higher, methane yields decreased sharply. When lipid concentrations were below 60%, the pH values were in the optimum range for the growth of methanogenic bacteria and the ratios of volatile fatty acid (VFA)/alkalinity were in the range of 0.2–0.6. When lipid concentrations exceeded 65%, the pH values were below 5.2, the reactor was acidized and the values of VFA/alkalinity rose to 2.0. The amount of Brevibacterium decreased with increasing lipid content. Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process, thereby inhibiting anaerobic digestion

Effects of lipid concentration on anaerobic co-digestion of municipal biomass wastes

Energy Technology Data Exchange (ETDEWEB)

Sun, Yifei, E-mail: sunif@buaa.edu.cn [School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Wang, Dian; Yan, Jiao [School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Qiao, Wei [College of Chemical Science and Engineering, China University of Petroleum, Beijing 102249 (China); Wang, Wei [School of Environment, Tsinghua University, Beijing 100084 (China); Zhu, Tianle [School of Chemistry and Environment, Beihang University, Beijing 100191 (China)

2014-06-01

Highlights: • Lipid in municipal biomass would not inhibited the anaerobic digestion process. • A lipid concentration of 65% of total VS was the inhibition concentration. • The amount of Brevibacterium decreased with the increasing of the lipid contents. • Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process. - Abstract: The influence of the lipid concentration on the anaerobic co-digestion of municipal biomass waste and waste-activated sludge was assessed by biochemical methane potential (BMP) tests and by bench-scale tests in a mesophilic semi-continuous stirred tank reactor. The effect of increasing the volatile solid (VS) concentration of lipid from 0% to 75% was investigated. BMP tests showed that lipids in municipal biomass waste could enhance the methane production. The results of bench-scale tests showed that a lipids concentration of 65% of total VS was the inhibition concentration. Methane yields increased with increasing lipid concentration when lipid concentrations were below 60%, but when lipid concentration was set as 65% or higher, methane yields decreased sharply. When lipid concentrations were below 60%, the pH values were in the optimum range for the growth of methanogenic bacteria and the ratios of volatile fatty acid (VFA)/alkalinity were in the range of 0.2–0.6. When lipid concentrations exceeded 65%, the pH values were below 5.2, the reactor was acidized and the values of VFA/alkalinity rose to 2.0. The amount of Brevibacterium decreased with increasing lipid content. Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process, thereby inhibiting anaerobic digestion.

Anaerobic methanethiol degradation and methanogenic community analysis in an alkaline (pH 10) biological process for liquefied petroleum gas desulfurization

NARCIS (Netherlands)

Leerdam, van R.C.; Bonilla-Salinas, M.; Bok, de F.A.M.; Bruning, H.; Lens, P.N.L.; Stams, A.J.M.; Janssen, A.J.H.

2008-01-01

Anaerobic methanethiol (MT) degradation by mesophilic (30 degrees C) alkaliphilic (pH 10) communities was studied in a lab-scale Upflow Anaerobic Sludge Bed (UASB) reactor inoculated with a mixture of sediments from the Wadden Sea (The Netherlands), Soap Lake (Central Washington), and Russian soda

Significance of dissolved methane in effluents of anaerobically ...

Science.gov (United States)

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10–30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11–100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Micro

Treatment of Alkaline Stripped Effluent in Aerated Constructed Wetlands: Feasibility Evaluation and Performance Enhancement

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Keli He

2016-09-01

Full Text Available Ammonium stripping has gained increasing interest for nitrogen recovery in anaerobically digested effluents. However, the stripped effluents often still do not meet discharge standards, having high pH and residual pollutants. Constructed wetlands (CWs are an easy to operate ecosystem and have a long history of application in treatment of wastewaters with extreme pH, such as acid mine drainage. However, knowledge of the mechanistic details involved in the use of CWs to treat high alkaline drainage, such as stripped effluent, is insufficient. This study explored the feasibility and effectiveness of using three sub-surface horizontal flow CWs to treat high alkaline stripped effluent (pH > 10. Two intensification strategies—intermittent aeration and effluent recirculation—were evaluated to enhance nitrogen depuration performance. The results show that the treatment of alkaline stripped effluent is feasible due to the high buffering capacity of the wetlands. Effluent recirculation combined with intermittent artificial aeration improves nitrogen removal, with 71% total nitrogen (TN removal. Ammonia volatilization from the surface of the wetlands in high alkaline conditions only contributed to 3% of the total removed ammonium. The microbial abundance and activity had significant diversity for the various enhancement strategies used in the constructed wetland systems. Anammox is an important process for nitrogen removal in CWs treating alkaline stripped effluent, and possible enhancements of this process should be investigated further.

Anaerobic co-digestion of canola straw and buffalo dung: optimization of methane production in batch experiments

International Nuclear Information System (INIS)

Sahito, A.R.; Brohi, K.M.

2014-01-01

In several regions of the Pakistan, crop cultivation is leading to the production crop residues and its disposal problems. It has been suggested that the co-digestion of the crop residues with the buffalo dung might be a disposal way for the wasted portion of the crops residue. The objective of present study was to optimize the anaerobic co-digestion of canola straw and the buffalo dung through batch experiments in order to obtain maximum methane production. The optimization was carried out in three stages. In first stage, the best canola straw to buffalo dung ratio was evaluated. In second stage, the best concentration of sodium hydrogen carbonate was assessedas the alkaline pretreatment chemical, whereas in the third stage most suitable particle size of the canola strawwas evaluated. The assessment criteria for the optimization of a co-digestion were cumulative methane production and ABD (Anaerobic Biodegradability). The results yield that anaerobic co-digestibility of the canola straw and the buffalo dung is obviously influenced by all the three factors of optimization. The maximum methane production was obtained as 911 NmL from the canola straw to buffalo dung ratio of 40:60, the alkaline doze of 0.6 gNaHCO/sub 3/ gVS and canola straw particle size of 2mm. However, because of the higher shredding cost to produce 2mm sized canola straw, particle size 4mm could be the best canola straw particle size. (author)

Anaerobic Co-Digestion of Canola Straw and Buffalo Dung: Optimization of Methane Production in Batch Experiments

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Abdul Razaque Sahito

2014-01-01

Full Text Available In several regions of the Pakistan, crop cultivation is leading to the production crop residues and its disposal problems. It has been suggested that the co-digestion of the crop residues with the buffalo dung might be a disposal way for the wasted portion of the crops' residue. The objective of present study was to optimize the anaerobic co-digestion of canola straw and the buffalo dung through batch experiments in order to obtain maximum methane production. The optimization was carried out in three stages. In first stage, the best canola straw to buffalo dung ratio was evaluated. In second stage, the best concentration of sodium hydrogen carbonate was assessedas the alkaline pretreatment chemical, whereas in the third stage most suitable particle size of the canola strawwas evaluated. The assessment criteria for the optimization of a co-digestion were cumulative methane production and ABD (Anaerobic Biodegradability. The results yield that anaerobic co-digestibility of the canola straw and the buffalo dung is obviously influenced by all the three factors of optimization. The maximum methane production was obtained as 911 NmL from the canola straw to buffalo dung ratio of 40:60, the alkaline doze of 0.6 gNaHCO3 / gVS and canola straw particle size of 2mm. However, because of the higher shredding cost to produce 2mm sized canola straw, particle size 4mm could be the best canola straw particle size.

Pretreatment and Anaerobic Co-digestion of Selected PHB and PLA Bioplastics

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Nicholas Benn

2018-01-01

Full Text Available Conventional petroleum-derived plastics are recalcitrant to biodegradation and can be problematic as they accumulate in the environment. In contrast, it may be possible to add novel, biodegradable bioplastics to anaerobic digesters at municipal water resource recovery facilities along with primary sludge to produce more biomethane. In this study, thermal and chemical bioplastic pretreatments were first investigated to increase the rate and extent of anaerobic digestion. Subsequently, replicate, bench-scale anaerobic co-digesters fed synthetic primary sludge with and without PHB bioplastic were maintained for over 170 days. Two polyhydroxybutyrate (PHB, one poly(3-hydroxybutyrate-co-4-hydroxybutyrate and one polylactic acid (PLA bioplastic were investigated. Biochemical methane potential (BMP assays were performed using both untreated bioplastic as well as bioplastic pretreated at elevated temperature (35–90°C under alkaline conditions (8anaerobic co-digesters fed synthetic primary sludge with PHB bioplastic resulted in 80–98% conversion of two PHB bioplastics to biomethane and a 5% biomethane production increase at the organic loadings employed (sludge OLR = 3.6 g COD per L of reactor volume per day [g COD/LR-d]; bioplastic OLR = 0.75 g theoretical oxygen demand per L of reactor volume per day [ThOD/LR-d] compared to digesters not fed bioplastics. Anaerobic digestion or co-digestion is a feasible management option for biodegradable plastics.

Anaerobic accumulation of short-chain fatty acids from algae enhanced by damaging cell structure and promoting hydrolase activity.

Science.gov (United States)

Feng, Leiyu; Chen, Yunzhi; Chen, Xutao; Duan, Xu; Xie, Jing; Chen, Yinguang

2018-02-01

Short-chain fatty acid (SCFAs) produced from harvested algae by anaerobic fermentation with uncontrolled pH was limited due to the solid cell structure of algae. This study, therefore, was undertaken to enhance the generation of SCFAs from algae by controlling the fermentation pH. pH influenced not only the total SCFAs production, but the percentage of individual SCFA. The maximal yield of SCFAs occurred at pH 10.0 and fermentation time of 6 d (3161 mg COD/L), which mainly contained acetic and iso-valeric acids and was nearly eight times that at uncontrolled pH (392 mg COD/L). Mechanism exploration revealed at alkaline pH, especially at pH 10.0, not only the cell structure of algae was damaged effectively, but also activities and relative quantification of hydrolases as well as the abundance of microorganisms responsible for organics hydrolysis and SCFAs production were improved. Also, the released microcystins from algae were removed efficiently during alkaline anaerobic fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover

International Nuclear Information System (INIS)

Xu Fuqing; Shi Jian; Lv Wen; Yu Zhongtang; Li Yebo

2013-01-01

Highlights: ► Compared methane production of solid AD inoculated with different effluents. ► Food waste effluent (FWE) had the largest population of acetoclastic methanogens. ► Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. ► Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. ► Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS feed , while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS feed . The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO 3 /kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents.

Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover

Energy Technology Data Exchange (ETDEWEB)

Xu Fuqing; Shi Jian [Department of Food, Agricultural and Biological Engineering, Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Ave., Wooster, OH 44691 (United States); Lv Wen; Yu Zhongtang [Department of Animal Sciences, Ohio State University, Columbus, OH 43210 (United States); Li Yebo, E-mail: li.851@osu.edu [Department of Food, Agricultural and Biological Engineering, Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Ave., Wooster, OH 44691 (United States)

2013-01-15

Highlights: Black-Right-Pointing-Pointer Compared methane production of solid AD inoculated with different effluents. Black-Right-Pointing-Pointer Food waste effluent (FWE) had the largest population of acetoclastic methanogens. Black-Right-Pointing-Pointer Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. Black-Right-Pointing-Pointer Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. Black-Right-Pointing-Pointer Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS{sub feed}, while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS{sub feed}. The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO{sub 3}/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents.

[Enhancement of anaerobic digestion of excess sludge by acid-alkali pretreatment].

Science.gov (United States)

Yuan, Guang-Huan; Zhou, Xing-Qiu; Wu, Jian-Dong

2012-06-01

In order to enhance the efficiency of anaerobic digestion of excess sludge, acid-alkali pretreatment method was studied. Three different pretreatment methods (alkali alone,acid-alkali, alkali-acid) were compared to investigate their impacts on hydrolysis and acidification of activated sludge. In addition, their influences on methane-producing in subsequent anaerobic digestion process were also studied. The results showed that the soluble chemical oxygen demand (SCOD) of alkaline treatment alone was about 16% higher than the combining of acid and alkali treatment, SCOD concentration increased to 5406.1 mg x L(-1) after 8 d pretreatment. After treated by acid (pH 4.0, 4 d) and alkali (pH 10.0, 4 d), the acetic acid production and its content in short-chain fatty acids (SCFAs) were higher than other pretreatment methods. And the acetic acid production (as COD/VSS) could reach 74.4 mg x g(-1), accounting for 60.5% of SCFAs. After acid-alkali pretreatment, the C: N ratio of the sludge mixed liquor was about 25, and the C: P ratio was between 35-40, which was more favorable than C: N and C: P ratio of alkali alone and alkali-acid to subsequent anaerobic digestion. The control experiments showed that, after acid-alkali pretreatment, anaerobic digestion cumulative methane yield (CH4/VSS(in)) reached to 136.1 mL x g(-1) at 15 d, which was about 2.5-, 1.6-, and 1.7-fold of the blank (unpretreated), alkali alone pretreatment and alkali-acid pretreatment, respectively. After acid-alkali pretreatment for 8 d and anaerobic digestion for 15 d, the removal efficiency of VSS was about 60.9%, and the sludge reduction effect was better than other pretreatments. It is obvious that the acid-alkali pretreatment method was more favorable to anaerobic digestion and sludge reduction.

Anaerobic methane oxidation and aerobic methane production in an east African great lake (Lake Kivu)

DEFF Research Database (Denmark)

Roland, Fleur A.E.; Morana, Cédric; Darchambeau, François

2018-01-01

We investigated CH4 oxidation in the water column of Lake Kivu, a deep meromictic tropical lake with CH4-rich anoxic deep waters. Depth profiles of dissolved gases (CH4 and N2O) and a diversity of potential electron acceptors for anaerobic CH4 oxidation (NO3 −, SO4 2−, Fe and Mn oxides) were dete...

Biotechnological application of sustainable biogas production through dry anaerobic digestion of Napier grass.

Science.gov (United States)

Dussadee, Natthawud; Ramaraj, Rameshprabu; Cheunbarn, Tapana

2017-05-01

Napier grass (Pennisetum purpureum), represents an interesting substrate for biogas production. The research project evaluated biogas potential production from dry anaerobic digestion of Napier grass using batch experiment. To enhance the biogas production from ensiled Napier grass, thermal and alkaline pre-treatments were performed in batch mode. Alkali hydrolysis of Napier grass was performed prior to batch dry anaerobic digestion at three different mild concentrations of sodium hydroxide (NaOH). The study results confirmed that NaOH pretreated sample produced high yield of biogas than untreated (raw) and hot water pretreated samples. Napier grass was used as the mono-substrate. The biogas composition of carbon dioxide (30.10%), methane (63.50%) and 5 ppm of H 2 S was estimated from the biogas. Therefore, fast-growing, high-yielding and organic matter-enriched of Napier grass was promising energy crop for biogas production.

Anaerobic Digestion Performance in the Energy Recovery of Kiwi Residues

Science.gov (United States)

Martins, Ramiro; Boaventura, Rui; Paulista, Larissa

2017-12-01

World production and trade of fruits generate losses in the harvest, post-harvest, handling, distribution and consumption phases, corresponding to 6.8% of total production. These residues present high potential as a substrate for the anaerobic digestion process and biogas generation. Thus, the energy valuation of the agro-industrial residues of kiwi production was evaluated by anaerobic digestion, aiming at optimizing the biogas production and its quality. Ten assays were carried out in a batch reactor (500 mL) under mesophilic conditions and varying a number of operational factors: different substrate/inoculum ratios; four distinct values for C: N ratio; inoculum from different digesters; and inoculum collected at different times of the year. The following parameters were used to control and monitor the process: pH, alkalinity, volatile fatty acids (VFA), volatile solids (VS) and chemical oxygen demand (COD). Among the tests performed, the best result obtained for the biogas production corresponded to the use of 2 g of substrate and 98 mL of inoculum of the anaerobic digester of the Wastewater Treatment Plant (WWTP) of Bragança, with addition of 150 mg of bicarbonate leading to a production of 1628 L biogas.kg-1 VS (57% methane). In relation to the biogas quality, the best result was obtained with 20 g of substrate and 380 mL of inoculum from the anaerobic digester sludge of WWTP of Ave (with addition 600 mg of sodium bicarbonate), presenting a value of 85% of CH4, with a production of 464 L biogas.kg-1 VS.

[Anaerobic bacteria isolated from patients with suspected anaerobic infections].

Science.gov (United States)

Ercis, Serpil; Tunçkanat, Ferda; Hasçelik, Gülşen

2005-10-01

The study involved 394 clinical samples sent to the Clinical Microbiology Laboratory of Hacettepe University Adult Hospital between January 1997 and May 2004 for anaerobic cultivation. Since multiple cultures from the same clinical samples of the same patient were excluded, the study was carried on 367 samples. The anaerobic cultures were performed in anaerobic jar using AnaeroGen kits (Oxoid, Basingstoke, U.K.) or GENbox (bioMérieux, Lyon, France). The isolates were identified by both classical methods and "BBL Crystal System" (Becton Dickinson, U.S.A.). While no growth was detected in 120 (32.7%) of the clinical samples studied, in 144 samples (39.2%) only aerobes, in 28 (7.6%) only anaerobes and in 75 (20.5%) of the samples both aerobes and anaerobes were isolated. The number of the anaerobic isolates was 217 from 103 samples with anaerobic growth. Of these 103 samples 15 showed single bacterial growth whereas in 88 samples multiple bacterial isolates were detected. Anaerobic isolates consisted of 92 Gram negative bacilli (Bacteroides spp. 50, Prevotella spp. 14, Porphyromonas spp. 10, Fusobacterium spp. 7, Tisierella spp. 2, unidentified 9), 57 Gram positive bacilli (Clostridium spp.17, Propionibacterium spp. 16, Lactobacillus spp. 8, Actinomyces spp. 5, Eubacterium spp. 2, Bifidobacterium adolescentis 1, Mobiluncus mulieris 1, unidentified nonspore forming rods 7), 61 Gram positive cocci (anaerobic cocci 44, microaerophilic cocci 17), and 7 Gram negative cocci (Veillonella spp.). In conclusion, in the samples studied with prediagnosis of anaerobic infection, Bacteroides spp. (23%) were the most common bacteria followed by anaerobic Gram positive cocci (20.3%) and Clostridium spp (7.8%).

Aerobic and anaerobic bacteria in tonsils of children with recurrent tonsillitis.

Science.gov (United States)

Brook, I; Yocum, P; Friedman, E M

1981-01-01

Tonsils were obtained from 50 children suffering from recurrent tonsillitis. Patients' ages ranged from 2.5 to 17 years (mean 6 years); 29 were males and 21 females. The tonsils were sectioned in half after heat searing of the surface and the core material was cultured for aerobic and anaerobic microorganisms. Mixed aerobic and anaerobic flora was obtained in all patients, yielding an average of 7.8 isolates (4.1 anaerobes and 3.7 aerobes) per specimen. There were 207 anaerobes isolated. The predominant isolates were 101 Bacteroides sp (including 10 B fragilis group, and 47 B melaninogenicus group), 29 Fusobacterium sp, 34 Gram-positive anaerobic cocci (25 Peptococcus sp and 9 Peptostreptococcus sp) and 16 Veillonella sp. There were 185 aerobic isolates. The predominant isolates were 41 alpha-hemolytic streptococci, 24 Staphylococcus aureus, 19 beta-hemolytic streptococci (11 group A, 4 group B, and 2 each group C and F), 14 Haemophilus sp (including 12 H influenzae type B) and 5 H parainfluenzae. Beta-lactamase production was noted in 56 isolates recovered from 37 tonsils. These were all isolates of S aureus (24) and B fragilis (10), 15 of 47 B melaninogenicus (32%), 5 of the 12 B oralis (42%), and 2 of 12 H influenzae type B (17%). Our findings indicate the polymicrobial aerobic and anaerobic nature of deep tonsillar flora in children with recurrent tonsillitis, and demonstrate the presence of many beta-lactamase-producing organisms in 74% of the patients.

Anaerobic Bacteria in Clinical Specimens - Frequent, But a Neglected Lot: A Five Year Experience at a Tertiary Care Hospital.

Science.gov (United States)

Shenoy, Padmaja Ananth; Vishwanath, Shashidhar; Gawda, Ashwini; Shetty, Seema; Anegundi, Renuka; Varma, Muralidhar; Mukhopadhyay, Chiranjay; Chawla, Kiran

2017-07-01

Anaerobic bacteria which constitute a significant proportion of the normal microbiota also cause variety of infections involving various anatomic sites. Considering the tedious culture techniques with longer turnaround time, anaerobic cultures are usually neglected by clinicians and microbiologists. To study the frequency of isolation of different anaerobic bacteria from various clinical specimens. A retrospective study to analyse the frequency of isolation of different anaerobic bacteria, was conducted over a period of five years from 2011 to 2015 including various clinical specimens submitted to anaerobic division of Microbiology laboratory. Anaerobic bacteria were isolated and identified following standard bacteriological techniques. Pathogenic anaerobes (n=336) were isolated from 278 (12.48%) of overall 2227 specimens processed with an average yield of 1.2 isolates. Anaerobes were isolated as polymicrobial flora with or without aerobic bacterial pathogens in 159 (57.2%) patients. Anaerobic Gram-negative bacilli (140, 41.7%) were the predominant isolates. B. fragilis group (67, 19.9%) were the most commonly isolated anaerobic pathogens. Anaerobes were predominantly isolated from deep seated abscess (23.9%). Pathogenic anaerobes were isolated from various infection sites. Unless culture and susceptibility tests are performed as a routine, true magnitude of antimicrobial resistance among anaerobic pathogens will not be known. Knowledge of the distribution of these organisms may assist in the selection of appropriate empirical therapy for anaerobic infections.

Controls on Methanogenesis in Organic-Rich Anaerobic Environments

Science.gov (United States)

Wilson, R.; Tfaily, M.; Chanton, J.; Rich, V. I.; Saleska, S. R.; Holmes, B.; Langford, L.; Hanson, P. J.; Bridgham, S. D.; Hopple, A.; Keller, J.; Cory, A.; Kostka, J. E.

2017-12-01

Peatlands contain an amount of C equal to half the CO2 in the atmosphere. That C is stored as organic C (OC) in peat deposits which form when plant productivity exceeds heterotrophic respiration. This balance has been attributed to cold, anaerobic, low pH conditions which slow microbial respiration rates, high aromatic content which may inhibit microbial decomposition, and recalcitrance of OC under terminal electron-acceptor (TEA) depleted conditions. Peat has been described as a potential C bomb which could release Gt of C into the atmosphere if rising global temperatures shifted this balance in favor of increased microbial respiration. At the Spruce and Peatlands Responses Under Changing Environments (SPRUCE) experimental site in Minnesota, U.S.A., peat up to 2 m deep was heated (+2.25°C to +9°C above ambient) both in situ and in laboratory incubations to test the response of microbial respiration to increasing temperatures. Our results demonstrated (1) that temperature did not influence CO2 or CH4 production rates in deep anaerobic peat, (2) that microbial decomposition was dominated by dissolved OC rather than the solid phase peat, and (3) that microbial decomposition in surface peat may become more methanogenic with warming. This shift towards higher CH4 production relative to CO2 has significant climate change implications since CH4 is a much stronger greenhouse gas than CO2. Under TEA-poor, anaerobic conditions, such as peat deposits, thermodynamic principles dictate that cellulose, the dominant OC form in Sphagnum peat, should be mineralized into equimolar CO2 and CH­4. However, deviations from this predicted ratio abound. The literature of rumen, a system similar to peat in many ways, revealed a potential mechanism for sustaining elevated CO2 production without accumulating inhibitory H2. Using FTICRMS, we found ubiquitous hydrogenation of unsaturated OC which could be acting as TEAs in peat deposits. This mechanism has the further advantages of

Using a combination of binning strategies and taxonomic approaches to unravel the anaerobic digestion microbiome

DEFF Research Database (Denmark)

Campanaro, Stefano; Treu, Laura; Kougias, Panagiotis

of scaffolds comprehensive of thousands genome sequences, but the binning of these scaffolds into OTUs representative of microbial genomes is still challenging. In the attempt to obtain a deep characterization of the anaerobic digestion microbiome, different metagenomic binning approaches were integrated...

Laboratory scale anaerobic digestion of fruit and vegetable solid waste

Energy Technology Data Exchange (ETDEWEB)

Lane, A.G.

1984-01-01

Anaerobic digestions that were fed waste apple, corn cobs, apple press cake, extracted sugarbeet pulp, pineapple pressings or asparagus waste were stable in trials lasting up to 226 days. Loading rates of 3.5-4.25 kg/m/sup 3/ day and conversions of 88-96% of the organic solids fed were obtained by ensuring adequate levels of alkalinity, nitrogen and other nutrients during digestion. Gas yields ranged from 0.429 to 0.568 litre (50-60% methane) per gram organic solids fed. For reasons not understood, gas yields from digestion of apricot waste declined after 63 days from 0.477 to 0.137 litre/g of feedstock. 22 references.

Interannual sedimentary effluxes of alkalinity in the southern North Sea: Model results compared with summer observations

OpenAIRE

Pätsch, Johannes; Kühn, Wilfried; Six, Katharina D.

2018-01-01

For the sediments of the central and southern North Sea different sources of alkalinity generation are quantified by a regional modelling system for the period 2000–2014. For this purpose a formerly global ocean sediment model coupled with a pelagic ecosystem model is adopted to shelf sea dynamics where much larger turnover rates than in the open and deep ocean occurs. To track alkalinity changes due to different nitrogen-related processes the open ocean sediment model was extended by t...

Experimental studies of the effect of irradiation on the anaerobic corrosion of carbon steel in relation to the Belgian supercontainer concept

Science.gov (United States)

Smart, N. R.; Fennell, P. A. H.; Rance, A. P.; Winsley, R. J.; Reddy, B.; Kursten, B.

2011-04-01

This paper describes recent results from an investigation of the effects of γ-radiation on the anaerobic corrosion of carbon steel in cement, in relation to the Belgian Supercontainer Concept for radioactive waste disposal. Anaerobic corrosion rates were measured by monitoring hydrogen evolution and the corresponding electrochemical behaviour was investigated by measuring open circuit potential and linear polarisation resistance. The test medium was alkaline simulated porewater, at γ-irradiation dose rates of 0 and 25 Gy hr-1, temperatures of 25 °C and 80 °C and chloride concentrations of 0 and 100 mg/l. The effects of radiation on the corrosion behaviour were found to be small.

Anaerobic Bacteria in Clinical Specimens – Frequent, But a Neglected Lot: A Five Year Experience at a Tertiary Care Hospital

Science.gov (United States)

Shenoy, Padmaja Ananth; Gawda, Ashwini; Shetty, Seema; Anegundi, Renuka; Varma, Muralidhar; Mukhopadhyay, Chiranjay; Chawla, Kiran

2017-01-01

Introduction Anaerobic bacteria which constitute a significant proportion of the normal microbiota also cause variety of infections involving various anatomic sites. Considering the tedious culture techniques with longer turnaround time, anaerobic cultures are usually neglected by clinicians and microbiologists. Aim To study the frequency of isolation of different anaerobic bacteria from various clinical specimens. Materials and Methods A retrospective study to analyse the frequency of isolation of different anaerobic bacteria, was conducted over a period of five years from 2011 to 2015 including various clinical specimens submitted to anaerobic division of Microbiology laboratory. Anaerobic bacteria were isolated and identified following standard bacteriological techniques. Results Pathogenic anaerobes (n=336) were isolated from 278 (12.48%) of overall 2227 specimens processed with an average yield of 1.2 isolates. Anaerobes were isolated as polymicrobial flora with or without aerobic bacterial pathogens in 159 (57.2%) patients. Anaerobic Gram-negative bacilli (140, 41.7%) were the predominant isolates. B. fragilis group (67, 19.9%) were the most commonly isolated anaerobic pathogens. Anaerobes were predominantly isolated from deep seated abscess (23.9%). Conclusion Pathogenic anaerobes were isolated from various infection sites. Unless culture and susceptibility tests are performed as a routine, true magnitude of antimicrobial resistance among anaerobic pathogens will not be known. Knowledge of the distribution of these organisms may assist in the selection of appropriate empirical therapy for anaerobic infections. PMID:28892897

Chemical reactivity of α-isosaccharinic acid in heterogeneous alkaline systems

International Nuclear Information System (INIS)

Glaus, M. A.; Loon, L. R. Van

2008-11-01

Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, α-isosaccharinic acid (α-ISA) is the strongest complexant. The prediction of the equilibrium concentration of α-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of α-ISA in heterogeneous alkaline model systems containing either Ca(OH) 2 or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of α-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, either at 25 o C or 90 o C, and under anaerobic atmospheres obtained by various methods. It was found that α-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than α-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was ∼50 % of the amount of α-ISA reacted. Sorption of α-ISA to Ca(OH) 2 contributed only to a minor extent to the loss of α-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of α-ISA. Under aerobic conditions α-ISA was quantitatively converted to reaction products, whereas under strict anaerobic conditions, only

Chemical reactivity of α-isosaccharinic acid in heterogeneous alkaline systems

International Nuclear Information System (INIS)

Glaus, M. A.; Loon, L. R. Van

2009-05-01

Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, α- isosaccharinic acid (α-ISA) is the strongest complexant. The prediction of the equilibrium concentration of α-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of α-ISA in heterogeneous alkaline model systems containing either Ca(OH) 2 or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of α-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, at either 25 o C or 90 o C, and under anaerobic atmospheres obtained by various methods. It was found that α-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than α-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was ∼ 50 % of the amount of α-ISA reacted. Sorption of α-ISA to Ca(OH) 2 contributed only to a minor extent to the loss of α-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of α-ISA. Under aerobic conditions α-ISA was quantitatively converted to reaction products, whereas under strict anaerobic conditions, only

Biogeochemistry of anaerobic crude oil biodegradation

Science.gov (United States)

Head, Ian; Gray, Neil; Aitken, Caroline; Sherry, Angela; Jones, Martin; Larter, Stephen

2010-05-01

Anaerobic degradation of crude oil and petroleum hydrocarbons is widely recognized as a globally significant process both in the formation of the world's vast heavy oil deposits and for the dissipation of hydrocarbon pollution in anoxic contaminated environments. Comparative analysis of crude oil biodegradation under methanogenic and sulfate-reducing conditions has revealed differences not only in the patterns of compound class removal but also in the microbial communities responsible. Under methanogenic conditions syntrophic associations dominated by bacteria from the Syntropheaceae are prevalent and these are likely key players in the initial anaerobic degradation of crude oil alkanes to intermediates such as hydrogen and acetate. Syntrophic acetate oxidation plays an important role in these systems and often results in methanogenesis dominated by CO2 reduction by members of the Methanomicrobiales. By contrast the bacterial communities from sulfate-reducing crude oil-degrading systems were more diverse and no single taxon dominated the oil-degrading sulfate-reducing systems. All five proteobacterial subdivisions were represented with Delta- and Gammaproteobacteria being detected most consistently. In sediments which were pasteurized hydrocarbon degradation continued at a relatively low rate. Nevertheless, alkylsuccinates characteristic of anaerobic hydrocarbon degradation accumulated to high concentrations. This suggested that the sediments harbour heat resistant, possibly spore-forming alkane degrading sulfate-reducers. This is particularly interesting since it has been proposed recently, that spore-forming sulfate-reducing bacteria found in cold arctic sediments may have originated from seepage of geofluids from deep subsurface hydrocarbon reservoirs.

Anaerobic bacteria in upper respiratory tract and head and neck infections: microbiology and treatment.

Science.gov (United States)

Brook, Itzhak

2012-04-01

Anaerobes are the predominant components of oropharyngeal mucous membranes bacterial flora, and are therefore a common cause of bacterial infections of endogenous origin of upper respiratory tract and head and neck. This review summarizes the aerobic and anaerobic microbiology and antimicrobials therapy of these infections. These include acute and chronic otitis media, mastoiditis and sinusitis, pharyngo-tonsillitis, peritonsillar, retropharyngeal and parapharyngeal abscesses, suppurative thyroiditis, cervical lymphadenitis, parotitis, siliadenitis, and deep neck infections including Lemierre Syndrome. The recovery from these infections depends on prompt and proper medical and when indicated also surgical management. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of increasing nitrobenzene loading rates on the performance of anaerobic migrating blanket reactor and sequential anaerobic migrating blanket reactor/completely stirred tank reactor system

International Nuclear Information System (INIS)

Kuscu, Ozlem Selcuk; Sponza, Delia Teresa

2009-01-01

A laboratory scale anaerobic migrating blanket reactor (AMBR) reactor was operated at nitrobenzene (NB) loading rates increasing from 3.33 to 66.67 g NB/m 3 day and at a constant hydraulic retention time (HRT) of 6 days to observe the effects of increasing NB concentrations on chemical oxygen demand (COD), NB removal efficiencies, bicarbonate alkalinity, volatile fatty acid (VFA) accumulation and methane gas percentage. Moreover, the effect of an aerobic completely stirred tank reactor (CSTR) reactor, following the anaerobic reactor, on treatment efficiencies was also investigated. Approximately 91-94% COD removal efficiencies were observed up to a NB loading rate of 30.00 g/m 3 day in the AMBR reactor. The COD removal efficiencies decreased from 91% to 85% at a NB loading rate of 66.67 g/m 3 day. NB removal efficiencies were approximately 100% at all NB loading rates. The maximum total gas, methane gas productions and methane percentage were found to be 4.1, 2.6 l/day and 59%, respectively, at a NB loading rate of 30.00 g/m 3 day. The optimum pH values were found to be between 7.2 and 8.4 for maximum methanogenesis. The total volatile fatty acid (TVFA) concentrations in the effluent were 110 and 70 mg/l in the first and second compartments at NB loading rates as high as 66.67 and 6.67 g/m 3 day, respectively, while they were measured as zero in the effluent of the AMBR reactor. In this study, from 180 mg/l NB 66 mg/l aniline was produced in the anaerobic reactor while aniline was completely removed and transformed to 2 mg/l of cathechol in the aerobic CSTR reactor. Overall COD removal efficiencies were found to be 95% and 99% for NB loading rates of 3.33 and 66.67 g/m 3 day in the sequential anaerobic AMBR/aerobic CSTR reactor system, respectively. The toxicity tests performed with Photobacterium phosphoreum (LCK 480, LUMIStox) and Daphnia magna showed that the toxicity decreased with anaerobic/aerobic sequential reactor system from the influent, anaerobic and to

Anaerobic Digestion: Process

DEFF Research Database (Denmark)

Angelidaki, Irini; Batstone, Damien J.

2011-01-01

Organic waste may degrade anaerobically in nature as well as in engineered systems. The latter is called anaerobic digestion or biogasification. Anaerobic digestion produces two main outputs: An energy-rich gas called biogas and an effluent. The effluent, which may be a solid as well as liquid...... with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9...

Acid-alkaline state of the blood in chronic combined effect of silicon dioxide, radon and tobacco smoke

International Nuclear Information System (INIS)

Ivanov, Z.; Charykchiev, D.

1987-01-01

Experimental observations were carried out on rats, subjected to inhalaion of radon-222 and combination of radon-222 with intratracheally introduced free silicon dioxide and tobacco smoke. A special method was used for anaerobic and narcosis-free taking of arterial blood from the left cardiac ventricle, the animals being investigated on the 2nd and the 6th month from the start of the experiment. In all tested animals a tendency to respiratory hypercapneic acidosis was established, particularly to the end of the experiment and in the group treated only with radon-222. In these animals a marked non-respiratory alkalosis with deviation of pH to alkaline direction was added. It is assumed that above-mentioned acid-alkaline disturbances could be due to the found morphological changes in the respiratory system, the liver and kidneys

Influence of alkalinity and VFAs on the performance of an UASB reactor with recirculation for the treatment of Tequila vinasses.

Science.gov (United States)

López-López, Alberto; León-Becerril, Elizabeth; Rosales-Contreras, María Elena; Villegas-García, Edgardo

2015-01-01

The main problem linked to the stability of upflow anaerobic sludge blanket (UASB) reactors during the treatment of Tequila vinasse is the high acidity and the null alkalinity present in this effluent. This research evaluates the effect of alkalinity and volatile fatty acids (VFAs) concentration on the performance of an UASB reactor with recirculation of the effluent for removing organic matter and biogas production from Tequila vinasses. Recirculation of the effluent reduces the impact of VFAs and organic matter concentration present in the influent, inducing the stability of the reactor. The UASB reactor was operated during 235 days at organic loading rates from 2.5 to 20.0 kg m(-3) d(-1), attaining a removal efficiency of COD greater than 75% with a methane yield of 335 ml CH4 g(-1) COD at SPT, maintaining a ratio of VFAs/Alk ≤ 0.5. Therefore, an optimal ratio of VFAs/Alk was established for the system operating in stable conditions for the treatment of Tequila vinasses. Under these conditions, the alkalinity was recuperated by the system itself, without the addition of external alkalinity.

PENGOLAHAN LIMBAH CAIR INDUSTRI FARMASI FORMULASI DENGAN METODE ANAEROB-AEROB DAN ANAEROB-KOAGULASI

OpenAIRE

Farida Crisnaningtyas; Hanny Vistanty

2016-01-01

Studi ini membahas mengenai pengolahan limbah cair industri farmasi dalam skala laboratorium dengan menggunakan konsep anaerob-kimia-fisika dan anaerob-aerob. Proses anaerob dilakukan dengan menggunakan reaktor Upflow Anaerobic Sludge Bed reactor (UASBr) pada kisaran OLR (Organic Loading Rate) 0,5 – 2 kg COD/m3hari, yang didahului dengan proses aklimatisasi menggunakan substrat gula. Proses anaerob mampu memberikan efisiensi penurunan COD hingga 74%. Keluaran dari proses anaerob diolah lebih ...

Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake

DEFF Research Database (Denmark)

Deutzmann, Joerg S.; Stief, Peter; Brandes, Josephin

2014-01-01

Anaerobic methane oxidation coupled to denitrification, also known as “nitrate/nitrite-dependent anaerobic methane oxidation” (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments......, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques...... in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were...

Anaerobes in pleuropulmonary infections

Directory of Open Access Journals (Sweden)

De A

2002-01-01

Full Text Available A total of 76 anaerobes and 122 aerobes were isolated from 100 patients with pleuropulmonary infections, e.g. empyema (64, pleural effusion (19 and lung abscess (13. In 14% of the patients, only anaerobes were recovered, while a mixture of aerobes and anaerobes was encountered in 58%. From all cases of lung abscess, anaerobic bacteria were isolated, alone (04 or along with aerobic bacteria (13. From empyema and pleural effusion cases, 65.6% and 68.4% anaerobes were recovered respectively. Amongst anaerobes, gram negative anaerobic bacilli predominated (Prevotella melaninogenicus 16, Fusobacterium spp. 10, Bacteroides spp. 9, followed by gram positive anaerobic cocci (Peptostreptococcus spp. 31. Coliform bacteria (45 and Pseudomonas aeruginosa (42 were the predominant aerobic isolates.

Anaerobic Psychrophiles from Alaska, Antarctica, and Patagonia: Implications to Possible Life on Mars and Europa

Science.gov (United States)

Hoover, Richard B.; Pikuta, Elena V.; Marsic, Damien; Ng, Joseph

2002-01-01

Microorganisms preserved within the permafrost, glaciers, and polar ice sheets of planet Earth provide analogs for microbial life forms that may be encountered in ice or permafrost of Mars, Europa, Callisto, Ganymede, asteroids, comets or other frozen worlds in the Cosmos. The psychrophilic and psychrotolerant microbes of the terrestrial cryosphere help establish the thermal and temporal limitations of life on Earth and provide clues to where and how we should search for evidence of life elsewhere in the Universe. For this reason, the cold-loving microorganisms are directly relevant to Astrobiology. Cryopreserved microorganisms can remain viable (in deep anabiosis) in permafrost and ice for millions of years. Permafrost, ice wedges, pingos, glaciers, and polar ice sheets may contain intact ancient DNA, lipids, enzymes, proteins, genes, and even frozen and yet viable ancient microbiota. Some microorganisms carry out metabolic processes in water films and brine, acidic, or alkaline channels in permafrost or ice at temperatures far below 0 C. Complex microbial communities live in snow, ice-bubbles, cryoconite holes on glaciers and ancient microbial ecosystems are cryopreserved within the permafrost, glaciers, and polar caps. In the Astrobiology group of the NASA Marshall Space Flight Center and the University of Alabama at Huntsville, we have employed advanced techniques for the isolation, culture, and phylogenetic analysis of many types of microbial extremophiles. We have also used the Environmental Scanning Electron Microscope to study the morphology, ultra-microstructure and chemical composition of microorganisms in ancient permafrost and ice. We discuss several interesting and novel anaerobic microorganisms that we have isolated and cultured from the Pleistocene ice of the Fox Tunnel of Alaska, guano of the Magellanic Penguin, deep-sea sediments from the vicinity of the Rainbow Hydrothermal Vent and enrichment cultures from ice of the Patriot Hills of Antarctica

A Simple Method for the Detection of Long-Chain Fatty Acids in an Anaerobic Digestate Using a Quartz Crystal Sensor

Directory of Open Access Journals (Sweden)

Takuro Kobayashi

2016-12-01

Full Text Available In anaerobic digestion (AD, long-chain fatty acids (LCFAs produced by hydrolysis of lipids, exhibit toxicity against microorganisms when their concentration exceeds several millimolar. An absorption detection system using a quartz crystal microbalance (QCM was developed to monitor the LCFA concentration during an anaerobic digester’s operation treating oily organic waste. The dissociation of the LCFAs considerably improved the sensor response and, moreover, enabled it to specifically detect LCFA from the mixture of LCFA and triglyceride. Under alkaline conditions, the frequency-shift rates of the QCM sensor linearly increased in accordance with palmitic acid concentration in the range of 0–100 mg/L. Frequency changes caused by anaerobic digestate samples were successfully measured after removing suspended solids and adjusting the pH to 10.7. Finally, the QCM measurements for digestate samples demonstrated that frequency-shift rates are highly correlated with LCFA concentrations, which confirmed that the newly developed QCM sensor is helpful for LCFA monitoring in terms of rapidness and usability.

Experimental studies of the effect of irradiation on the anaerobic corrosion of carbon steel in relation to the Belgian supercontainer concept

Directory of Open Access Journals (Sweden)

Reddy B.

2011-04-01

Full Text Available This paper describes recent results from an investigation of the effects of γ-radiation on the anaerobic corrosion of carbon steel in cement, in relation to the Belgian Supercontainer Concept for radioactive waste disposal. Anaerobic corrosion rates were measured by monitoring hydrogen evolution and the corresponding electrochemical behaviour was investigated by measuring open circuit potential and linear polarisation resistance. The test medium was alkaline simulated porewater, at γ-irradiation dose rates of 0 and 25 Gy hr−1, temperatures of 25 °C and 80 °C and chloride concentrations of 0 and 100 mg/l. The effects of radiation on the corrosion behaviour were found to be small.

Antibiotic Susceptibility Pattern of Aerobic and Anaerobic Bacteria Isolated From Surgical Site Infection of Hospitalized Patients.

Science.gov (United States)

Akhi, Mohammad Taghi; Ghotaslou, Reza; Beheshtirouy, Samad; Asgharzadeh, Mohammad; Pirzadeh, Tahereh; Asghari, Babak; Alizadeh, Naser; Toloue Ostadgavahi, Ali; Sorayaei Somesaraei, Vida; Memar, Mohammad Yousef

2015-07-01

Surgical Site Infections (SSIs) are infections of incision or deep tissue at operation sites. These infections prolong hospitalization, delay wound healing, and increase the overall cost and morbidity. This study aimed to investigate anaerobic and aerobic bacteria prevalence in surgical site infections and determinate antibiotic susceptibility pattern in these isolates. One hundred SSIs specimens were obtained by needle aspiration from purulent material in depth of infected site. These specimens were cultured and incubated in both aerobic and anaerobic condition. For detection of antibiotic susceptibility pattern in aerobic and anaerobic bacteria, we used disk diffusion, agar dilution, and E-test methods. A total of 194 bacterial strains were isolated from 100 samples of surgical sites. Predominant aerobic and facultative anaerobic bacteria isolated from these specimens were the members of Enterobacteriaceae family (66, 34.03%) followed by Pseudomonas aeruginosa (26, 13.4%), Staphylococcus aureus (24, 12.37%), Acinetobacter spp. (18, 9.28%), Enterococcus spp. (16, 8.24%), coagulase negative Staphylococcus spp. (14, 7.22%) and nonhemolytic streptococci (2, 1.03%). Bacteroides fragilis (26, 13.4%), and Clostridium perfringens (2, 1.03%) were isolated as anaerobic bacteria. The most resistant bacteria among anaerobic isolates were B. fragilis. All Gram-positive isolates were susceptible to vancomycin and linezolid while most of Enterobacteriaceae showed sensitivity to imipenem. Most SSIs specimens were polymicrobial and predominant anaerobic isolate was B. fragilis. Isolated aerobic and anaerobic strains showed high level of resistance to antibiotics.

The anaerobic degradation of organic matter in Danish coastal sediments: iron reduction, manganese reduction, and sulfate reduction

DEFF Research Database (Denmark)

Canfield, Donald Eugene; Thamdrup, B; Hansen, Jens Würgler

1993-01-01

). In the deep portion of the basin, surface Mn enrichments reached 3.5 wt%, and Mn reduction was the only important anaerobic carbon oxidation process in the upper 10 cm of the sediment. In the less Mn-rich sediments from intermediate depths in the basin, Fe reduction ranged from somewhat less, to far more...... speculate that in shallow sediments of the Skagerrak, surface Mn oxides are present in a somewhat reduced oxidation level (deep basin....

The utility of anaerobic blood culture in detecting facultative anaerobic bacteremia in children.

Science.gov (United States)

Shoji, Kensuke; Komuro, Hisako; Watanabe, Yasushi; Miyairi, Isao

2013-08-01

Routine anaerobic blood culture is not recommended in children because obligate anaerobic bacteremia is rare in the pediatric population. However, a number of facultative anaerobic bacteria can cause community and hospital acquired infections in children and the utility of anaerobic blood culture for detection of these organisms is still unclear. We conducted a retrospective analysis of all blood culture samples (n = 24,356) at a children's hospital in Japan from October 2009 to June 2012. Among the samples that had paired aerobic and anaerobic blood cultures, 717 samples were considered clinically significant with 418 (58%) organisms detected from both aerobic and anaerobic cultures, 167 (23%) detected only from aerobic culture and 132 (18%) detected only from anaerobic culture. While most facultative anaerobes were detectable by aerobic culture, over 25% of Enterobacteriaceae and 15% of Staphylococcus sp. were detected from anaerobic cultures bottles only, suggesting its potential role in selected settings. Copyright © 2013 Elsevier Inc. All rights reserved.

Anaerobic digestion of tuna waste for the production of volatile fatty acids.

Science.gov (United States)

Bermúdez-Penabad, Noela; Kennes, Christian; Veiga, Maria C

2017-10-01

Fish canning industries generate a significant amount of solid waste that can be digested anaerobically into volatile fatty acids (VFA). The aim of this research was to study the effect of various pHs, ranging from 5.0 to 10.0, and percentage of total solids on the anaerobic digestion of tuna waste into VFA, both in batch assays and continuous reactor. The production of VFA was affected by pH and was significantly higher under alkaline conditions. At pH 8.0, the VFA production reached 30,611mgCOD/L. The VFA mainly consisted of acetic, propionic, n-butyric and i-valeric acids. Acetic acid was the main product at all the pHs tested. In terms of total solids (TS) the best results were obtained with 2.5% total solids, reaching 0.73gCOD VFA /gCOD waste . At higher TS concentrations (5 and 8% TS) lower yields were reached probably due to inhibition at high VFA concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anaerobic digestion of food waste stabilized by lime mud from papermaking process.

Science.gov (United States)

Zhang, Jishi; Wang, Qinqing; Zheng, Pengwei; Wang, Yusong

2014-10-01

The effects of lime mud from papermaking process (LMP) addition as buffer agent and inorganic nutrient on the anaerobic digestion stability of food waste (FW) were investigated under mesophilic conditions with the aim of avoiding volatile fatty acids accumulation, and inorganic elements deficiency. When LMP concentration ranged from 6.0 to 10g/L, the FW anaerobic digestion could maintain efficient and stable state. These advantages are attributed to the existence of Ca, Na, Mg, K, Fe, and alkaline substances that favor the methanogenic process. The highest CH4 yield of 272.8mL/g-VS was obtained at LMP and VS concentrations of 10.0 and 19.8g/L, respectively, with the corresponding lag-phase time of 3.84d and final pH of 8.4. The methanogens from residue digestates mainly consisted of Methanobrevibacter, coccus-type and sarcina-type methanogens with LMP addition compared to Methanobacteria in control. However, higher concentration of LMP inhibited methanogenic activities and methane production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Leaching characteristics of poultry litter in first phase of multistage anaerobic digestion

Directory of Open Access Journals (Sweden)

Surya P Sunkavalli

2014-05-01

Full Text Available Poultry litter is highly biodegradable in nature. Therefore, it could be subjected to biomethanation to produce valuable biogas and bio-manure as byproducts. Some studies have been conducted along these lines in India by utilizing the poultry litter as a substrate in batch type dung digesters of KVIC and DENABANDHU models. However, these reactors have the drawbacks of high residence time (30 – 35 days, scum formation problems etc. Moreover, these batch type plants are not suitable for the treatment of large quantities of solid waste. Multistage anaerobic digestion has the potential to overcome some of the aforesaid issues. Anaerobic leaching experiments were conducted at different total solids concentration and pH using poultry litter in order to evaluate the leachate quality for a period of 7 days. The increase in Total solids (TS % from 15 to 20% show inverse effect on VFA and Alkalinity. The change in pH from 8.5 to 5.5 didn’t show much impact on VFA but there is a small impact on alkalinity. It was also observed that the leaching of the organic matter in the solid to the liquid phase is very fast and it is taking place approximately in three to four days and subsequently leachate getting saturated. Therefore, reactor set up was made in the last phase to regularly remove the water from the reactor so that higher driving force is available for leaching. The study resulted in leaching of maximum organic content in the solid to liquid within three days. DOI: http://dx.doi.org/10.3126/ije.v3i2.10516 International Journal of the Environment Vol.3(2 2014: 76-82

PENGOLAHAN LIMBAH CAIR INDUSTRI FARMASI FORMULASI DENGAN METODE ANAEROB-AEROB DAN ANAEROB-KOAGULASI

Directory of Open Access Journals (Sweden)

Farida Crisnaningtyas

2016-05-01

Full Text Available Studi ini membahas mengenai pengolahan limbah cair industri farmasi dalam skala laboratorium dengan menggunakan konsep anaerob-kimia-fisika dan anaerob-aerob. Proses anaerob dilakukan dengan menggunakan reaktor Upflow Anaerobic Sludge Bed reactor (UASBr pada kisaran OLR (Organic Loading Rate 0,5 – 2 kg COD/m3hari, yang didahului dengan proses aklimatisasi menggunakan substrat gula. Proses anaerob mampu memberikan efisiensi penurunan COD hingga 74%. Keluaran dari proses anaerob diolah lebih lanjut dengan menggunakan dua opsi proses: (1 fisika-kimia, dan (2 aerob. Koagulan alumunium sulfat dan flokulan kationik memberikan efisiensi penurunan COD tertinggi (73% pada kecepatan putaran masing-masing 100 rpm dan 40 rpm. Uji coba aerob dilakukan pada kisaran MLSS antara 4000-5000 mg/L dan mampu memberikan efisiensi penurunan COD hingga 97%. Hasil uji coba menunjukkan bahwa efisiensi penurunan COD total yang dapat dicapai dengan menggunakan teknologi anaerob-aerob adalah 97%, sedangkan kombinasi anaerob-koagulasi-flokulasi hanya mampu menurunkan COD total sebesar 72,53%. Berdasarkan hasil tersebut, kombinasi proses anaerob-aerob merupakan teknologi yang potensial untuk diaplikasikan dalam sistem pengolahan limbah cair industri farmasi. 

Recent developments in the thermophilic microbiology of deep-sea hydrothermal vents.

Science.gov (United States)

Miroshnichenko, Margarita L; Bonch-Osmolovskaya, Elizaveta A

2006-04-01

The diversity of thermophilic prokaryotes inhabiting deep-sea hot vents was actively studied over the last two decades. The ever growing interest is reflected in the exponentially increasing number of novel thermophilic genera described. The goal of this paper is to survey the progress in this field made in the years 2000-2005. In this period, representatives of several new taxa of hyperthermophilic archaea were obtained from deep-sea environments. Two of these isolates had phenotypic features new for this group of organisms: the presence of an outer cell membrane (the genus Ignicoccus) and the ability to grow anaerobically with acetate and ferric iron (the genus Geoglobus). Also, our knowledge on the diversity of thermophilic bacteria from deep-sea thermal environments extended significantly. The new bacterial isolates represented diverse bacterial divisions: the phylum Aquificae, the subclass Epsilonproteobacteria, the order Thermotogales, the families Thermodesulfobacteriaceae, Deferribacteraceae, and Thermaceae, and a novel bacterial phylum represented by the genus Caldithrix. Most of these isolates are obligate or facultative lithotrophs, oxidizing molecular hydrogen in the course of different types of anaerobic respiration or microaerobic growth. The existence and significant ecological role of some of new bacterial thermophilic isolates was initially established by molecular methods.

Carbon steel corrosion under anaerobic-aerobic cycling conditions in near-neutral pH saline solutions - Part 1: Long term corrosion behaviour

International Nuclear Information System (INIS)

Sherar, B.W.A.; Keech, P.G.; Shoesmith, D.W.

2011-01-01

Highlights: → Anaerobic-aerobic cycling on pipeline steel forms two distinct surface morphologies. → Seventy-five percentage of the surface was covered by a black, compact layer ∼4.5 μm thick. → A tubercle, ∼3 to 4 mm in cross section, covered the remaining 25% of surface. → The tubercle cross section showed a single large pit ∼275 μm deep. - Abstract: The influence of anaerobic-aerobic cycling on pipeline steel corrosion was investigated in near-neutral carbonate/sulphate/chloride solution (pH 9) over 238 days. The corrosion rate increased and decreased as exposure conditions were switched between redox conditions. Two distinct corrosion morphologies were observed. The majority of the surface corroded uniformly to produce a black magnetite/maghemite layer approximately 4.5 μm thick. The remaining surface was covered with an orange tubercle, approximately 3-4 mm in cross section. Analysis of the tubercle cross section revealed a single large pit approximately 275 μm deep. Repeated anaerobic-aerobic cycling localized the corrosion process within this tubercle-covered pit.

Chemical reactivity of {alpha}-isosaccharinic acid in heterogeneous alkaline systems

Energy Technology Data Exchange (ETDEWEB)

Glaus, M. A.; Loon, L. R. Van

2009-05-15

Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, {alpha}- isosaccharinic acid ({alpha}-ISA) is the strongest complexant. The prediction of the equilibrium concentration of {alpha}-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of {alpha}-ISA in heterogeneous alkaline model systems containing either Ca(OH){sub 2} or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of {alpha}-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, at either 25 {sup o}C or 90 {sup o}C, and under anaerobic atmospheres obtained by various methods. It was found that {alpha}-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than {alpha}-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was {approx} 50 % of the amount of {alpha}-ISA reacted. Sorption of {alpha}-ISA to Ca(OH){sub 2} contributed only to a minor extent to the loss of {alpha}-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of {alpha}-ISA. Under aerobic conditions {alpha}-ISA was

Radium, uranium and metals in acidic or alkaline uranium mill

International Nuclear Information System (INIS)

Somot, St.

1997-01-01

Uranium mill study sites have been chosen in function of their different characteristics: deposits age, treatment nature (alkaline or acid), mill origin. The realization of specific drilling allowed the simultaneous study of the interstitial water and the solid fraction of samples, cut at determined deep. A radiation imbalance between 230 Th and 226 Ra is observed in the acid treatment residues. The trace elements concentration spectrum is directly bound to the nature of the ore. Diamagnetic evolutions are observed in residues. The uranium concentrations are higher in carbonated waters than in calcic sulfated waters. The selective sequential lixiviation showed that the 226 Ra activity of the interstitial water is controlled by the Gypsum in acid treatment residues. In other hand in the alkaline treatment waters, the carbonates occur. The Ra retention is largely bound to the Fe and Mn oxy-hydroxides. (A.L.B.)

Electrochemical Corrosion Investigations on Anaerobic Treated Distillery Effluent

Science.gov (United States)

Ram, Chhotu; Sharma, Chhaya; Singh, A. K.

2014-09-01

Present study is focused on the corrosivity of anaerobic treated distillery effluent and corrosion performance of mild steel and stainless steels. Accordingly, electrochemical polarization tests were performed in both treated distillery and synthetic effluents. Polarization tests were also performed in synthetic solutions and it was observed that Cl- and K+ increase whereas SO4 -, PO4 -, NO3 -, and NO2 - decrease the corrosivity of effluent at alkaline pH. Further, comparison in corrosivity of distillery and synthetic effluents shows the former to be less corrosive and this is assigned due to the presence of amino acids and melanoidins. Mild steel experienced to have the highest corrosion rate followed by stainless steels—304L and 316L and lowest in case of SAF 2205. Relative corrosion resistance of stainless steels is observed to depend upon Cr, Mo, and N content.

Arsenic, Anaerobes, and Autotrophy.

Science.gov (United States)

Oremland, R. S.

2008-12-01

That microbes have resistance to the toxic arsenic oxyanions arsenite [As(III)] and arsenate [As(V)] has been recognized for some time. More recently it was shown that certain prokaryotes can demonstrate As- dependent growth by conserving the energy gained from the aerobic oxidation of As(III) to As(V), or from the reduction of As(V) to As(III) under anaerobic conditions. During the course of our field studies of two alkaline, hypersaline soda lakes (Mono Lake and Searles Lake, CA) we have discovered several new anaerobic chemo- and photo-autotrophic bacteria that can center their energy gain around the redox reactions between As(III) and As(V). Alkalilimnicola ehrlichii, isolated from the water column of Mono Lake is a nitrate-respiring, As(III)-oxidizing chemoautotroph of the gamma-proteobacteria that has a highly flexible metabolism. It can function either as a facultative anaerobe or as a chemo-autotroph, or as a heterotroph (Hoeft et al., 2007). In contrast, strain MLMS-1 of the delta-proteobacteria was also isolated from Mono Lake, but to date is the first example of an obligate As(V)-respirer that is also an obligate chemo-autotroph, gaining its energy via the oxidation of sulfide to sulfate (Hoeft et al., 2004). Strain SLAS-1, isolated from salt-saturated Searles Lake is a member of the Halananerobiales, and can either grow as a heterotroph (lactate e-donor) or chemo- autotroph (sulfide e-donor) while respiring As(V). The fact that it can achieve this feat at salt-saturation (~ 340 g/L) makes it a true extremophile (Oremland et. al., 2005). Finally, strain PHS-1 isolated from a hot spring on Paoha island in Mono Lake is the first example of a photosynthetic bacterium of the gamma- proteobacteria able to link its growth to As(III)-dependent anoxygenic photosynthesis (Kulp et al., 2008). These novel microbes give us new insights into the evolution of arsenic-based metabolism and their role in the biogeochemical cycling of this toxic element. Hoeft, S.E., et

Anaerobic bacteria

Science.gov (United States)

Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

Anaerobic bacteria in 118 patients with deep-space head and neck infections from the University Hospital of Maxillofacial Surgery, Sofia, Bulgaria.

Science.gov (United States)

Boyanova, Lyudmila; Kolarov, Rossen; Gergova, Galina; Deliverska, Elitsa; Madjarov, Jivko; Marinov, Milen; Mitov, Ivan

2006-09-01

The aim of this study was to assess the incidence and susceptibility to antibacterial agents of anaerobic strains in 118 patients with head and neck abscesses (31) and cellulitis (87). Odontogenic infection was the most common identified source, occurring in 73 (77.7%) of 94 patients. The incidence of anaerobes in abscesses and cellulitis was 71 and 75.9%, respectively, and that in patients before (31 patients) and after (87) the start of empirical treatment was 80.6 and 72.4%, respectively. The detection rates of anaerobes in patients with odontogenic and other sources of infection were 82.2 and 71.4%, respectively. In total, 174 anaerobic strains were found. The predominant bacteria were Prevotella (49 strains), Fusobacterium species (22), Actinomyces spp. (21), anaerobic cocci (20) and Eubacterium spp. (18). Bacteroides fragilis strains were isolated from 7 (5.9%) specimens. The detection rate of Fusobacterium strains from non-treated patients (32.2%) was higher than that from treated patients (13.8%). Resistance rates to clindamycin and metronidazole of Gram-negative anaerobes were 5.4 and 2.5%, respectively, and those of Gram-positive species were 4.5 and 58.3%, respectively. One Prevotella strain was intermediately susceptible to ampicillin/sulbactam. In conclusion, the start of empirical treatment could influence the frequency or rate of isolation of Fusobacterium species. The involvement of the Bacteroides fragilis group in some head and neck infections should be considered.

Anaerobic corrosion of carbon steel under unsaturated conditions in a nuclear waste deep geological repository

International Nuclear Information System (INIS)

Kwong, G.; Wang, St.; Newman, R.C.

2009-01-01

Full text of publication follows: Anaerobic corrosion behaviour of carbon steel in humid conditions, but not submerged in aqueous solution, was studied based on hydrogen generation. Initial tests monitored the hydrogen evolution from carbon steel in a high humidity environment (≥ 75% RH) at near-ambient temperature (30 C) using a high sensitivity pressure gauge system (sensitivity of 0.01 μm.a -1 ). The presence of hydrogen in test runs that showed no, or minimal, pressure increase was confirmed by a solid-state potentiometric hydrogen sensor which has the capability of detecting hydrogen partial pressure as low as 10 -6 bar or a corrosion rate of 1.5 * 10 -4 μm.a -1 . Preliminary results indicate that a corrosion rate as high as 0.2 μm.a -1 can be sustained for steel coated with salt at 100% RH. Higher corrosion rates (as high as 0.8 μm.a -1 ) were obtained in less humid environment (71% RH). Without a salt deposit, pickled steel in humid environment (as high as 100% RH) also showed detectable corrosion for a period up to 800 hours, during which 0.8 kPa of hydrogen was accumulated prior to the apparent arrest of corrosion, representing a metal loss of 3 nm. Corrosion scales are also identified with x-ray photoelectron spectroscopy (XPS) as well as by mass change monitoring using a quartz crystal microbalance. Corrosion mechanisms and prediction for longer-term exposure will be discussed. Results will be useful in predicting long-term carbon steel corrosion behaviour and improving the current knowledge of hydrogen gas evolution in a deep geological repository for nuclear waste. (authors)

Draft genome of an Aerophobetes bacterium reveals a facultative lifestyle in deep-sea anaerobic sediments

KAUST Repository

Wang, Yong

2016-07-01

Aerophobetes (or CD12) is a recently defined bacterial phylum, of which the metabolic processes and ecological importance remain unclear. In the present study, we obtained the draft genome of an Aerophobetes bacterium TCS1 from saline sediment near the Thuwal cold seep in the Red Sea using a genome binning method. Analysis of 16S rRNA genes of TCS1 and close relatives revealed wide distribution of Aerophobetes in deep-sea sediments. Phylogenetic relationships showed affinity between Aerophobetes TCS1 and some thermophilic bacterial phyla. The genome of TCS1 (at least 1.27 Mbp) contains a full set of genes encoding core metabolic pathways, including glycolysis and pyruvate fermentation to produce acetyl-CoA and acetate. The identification of cross-membrane sugar transporter genes further indicates its potential ability to consume carbohydrates preserved in the sediment under the microbial mat. Aerophobetes bacterium TCS1 therefore probably carried out saccharolytic and fermentative metabolism. The genes responsible for autotrophic synthesis of acetyl-CoA via the Wood–Ljungdahl pathway were also found in the genome. Phylogenetic study of the essential genes for the Wood–Ljungdahl pathway implied relative independence of Aerophobetes bacterium from the known acetogens and methanogens. Compared with genomes of acetogenic bacteria, Aerophobetes bacterium TCS1 genome lacks the genes involved in nitrogen metabolism, sulfur metabolism, signal transduction and cell motility. The metabolic activities of TCS1 might depend on geochemical conditions such as supplies of CO2, hydrogen and sugars, and therefore the TCS1 might be a facultative bacterium in anaerobic saline sediments near cold seeps. © 2016, Science China Press and Springer-Verlag Berlin Heidelberg.

In situ test plan for concrete materials using low alkaline cement at Horonobe URL

International Nuclear Information System (INIS)

Kobayashi, Yasushi; Yamada, Tsutomu; Nakayama, Masashi; Matsui, Hiroya; Matsuda, Takeshi; Konishi, Kazuhiro; Iriya, Keishiro; Noda, Masaru

2007-03-01

HLW (high-level radioactive waste) repository is to be constructed at depths of over three hundred meters below the surface. Shotcrete and lining will be used for safety under construction and operational period. Concrete is a kind of composite material which is constituted by aggregate, cement and additives. Low alkaline cement has been developed from the viewpoint of long term stability of the barrier systems which would be influenced by high alkaline arising from cement material. HFSC (Highly Fly-ash contained Silica-fume Cement) is one of a low alkaline cement, which contains silica fume and coal ash. It has been developed in Japan Atomic Energy Agency (JAEA). JAEA are now implementing the construction of the under ground research laboratory (URL) at Horonobe for the purpose of research in deep geological science and repository engineering technology. This report shows the in situ test plan for shotcrete using HFSC at Horonobe URL with identifying requirements for cement materials to be used in HLW repository, and also reviews major literatures of low alkaline cement. This in situ test plan is aiming to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. (author)

Accelerated anaerobic hydrolysis rates under a combination of intermittent aeration and anaerobic conditions

DEFF Research Database (Denmark)

Jensen, T. R.; Lastra Milone, T.; Petersen, G.

2017-01-01

Anaerobic hydrolysis in activated return sludge was investigated in laboratory scale experiments to find if intermittent aeration would accelerate anaerobic hydrolysis rates compared to anaerobic hydrolysis rates under strict anaerobic conditions. The intermittent reactors were set up in a 240 h...... for calculating hydrolysis rates based on soluble COD were compared. Two-way ANOVA with the Bonferroni post-test was performed in order to register any significant difference between reactors with intermittent aeration and strictly anaerobic conditions respectively. The experiment demonstrated a statistically...... significant difference in favor of the reactors with intermittent aeration showing a tendency towards accelerated anaerobic hydrolysis rates due to application of intermittent aeration. The conclusion of the work is thus that intermittent aeration applied in the activated return sludge process (ARP) can...

Microbial diversity in a permanently cold and alkaline environment in Greenland

DEFF Research Database (Denmark)

Glaring, Mikkel Andreas; Vester, Jan Kjølhede; Lylloff, Jeanette Eva

2015-01-01

The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C) and alkaline (above pH 10) environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting...... the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference...... in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic...

High-solid Anaerobic Co-digestion of Sewage Sludge and Cattle Manure: The Effects of Volatile Solid Ratio and pH

Science.gov (United States)

Dai, Xiaohu; Chen, Yang; Zhang, Dong; Yi, Jing

2016-01-01

High-solid anaerobic digestion is an attractive solution to the problem of sewage sludge disposal. One method that can be used to enhance the production of volatile fatty acids (VFAs) and the generation of methane from anaerobic digestion involves combining an alkaline pretreatment step with the synergistic effects of sewage sludge and cattle manure co-digestion, which improves the activity of key enzymes and microorganisms in the anaerobic co-digestion system to promote the digestion of organic waste. In this study, we describe an efficient strategy that involves adjusting the volatile solid (VS) ratio (sewage sludge/cattle manure: 3/7) and initial pH (9.0) to improve VFA production and methane generation from the co-digestion of sludge and manure. The experimental results indicate that the maximum VFA production was 98.33 g/kg-TS (total solid) at the optimal conditions. Furthermore, methane generation in a long-term semi-continuously operated reactor (at a VS ratio of 3/7 and pH of 9.0) was greater than 120.0 L/kg-TS. PMID:27725704

Anaerobic biodegradability of macropollutants

DEFF Research Database (Denmark)

Angelidaki, Irini

2002-01-01

A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors...

Influence of initial pH on thermophilic anaerobic co-digestion of swine manure and maize stalk.

Science.gov (United States)

Zhang, Tong; Mao, Chunlan; Zhai, Ningning; Wang, Xiaojiao; Yang, Gaihe

2015-01-01

The contradictions between the increasing energy demand and decreasing fossil fuels are making the use of renewable energy the key to the sustainable development of energy in the future. Biogas, a renewable clean energy, can be obtained by the anaerobic fermentation of manure waste and agricultural straw. This study examined the initial pH value had obvious effect on methane production and the process in the thermophilic anaerobic co-digestion. Five different initial pH levels with three different manure ratios were tested. All digesters in different initial pH showed a diverse methane production after 35 days. The VFA/alkalinity ratio of the optimum reaction condition for methanogens activity was in the range of 0.1-0.3 and the optimal condition that at the 70% dung ratio and initial pH 6.81, was expected to achieve maximum total biogas production (146.32 mL/g VS). Copyright © 2014 Elsevier Ltd. All rights reserved.

Anaerobic digestion of onion residuals using a mesophilic Anaerobic Phased Solids Digester

International Nuclear Information System (INIS)

Romano, Rowena T.; Zhang, Ruihong

2011-01-01

The anaerobic digestion of onion residual from an onion processing plant was studied under batch-fed and continuously-fed mesophilic (35 ± 2 o C) conditions in an Anaerobic Phased Solids (APS) Digester. The batch digestion tests were performed at an initial loading of 2.8 gVS L -1 and retention time of 14 days. The biogas and methane yields, and volatile solids reduction from the onion residual were determined to be 0.69 ± 0.06 L gVS -1 , 0.38 ± 0.05 L CH 4 gVS -1 , and 64 ± 17%, respectively. Continuous digestion tests were carried out at organic loading rates (OLRs) of 0.5-2.0 gVS L -1 d -1 . Hydrated lime (Ca(OH) 2 ) was added to the APS-Digester along with the onion residual at 16 mg Ca(OH) 2 gVS -1 to control the pH of the biogasification reactor above 7.0. At steady state the average biogas yields were 0.51, 0.56, and 0.62 L gVS -1 for the OLRs of 0.5, 1.0, and 2.0 gVS L -1 d -1 respectively. The methane yields at steady state were 0.29, 0.32, and 0.31 L CH 4 gVS -1 for the OLRs of 0.5, 1.0, and 2.0 gVS L -1 d -1 respectively. The study shows that the digestion of onion residual required proper alkalinity and pH control, which was possible through the use of caustic chemicals. However, such chemicals will begin to have an inhibitory effect on the microbial population at high loading rates, and therefore alternative operational parameters are needed. -- Highlights: → An APS-Digester was used to study biogas production from onion solid residues. → Biogas and methane yields from onion solids were determined. → Study showed substantial findings for treating onion solid residues.

Regional Variation of CH4 and N2 Production Processes in the Deep Aquifers of an Accretionary Prism.

Science.gov (United States)

Matsushita, Makoto; Ishikawa, Shugo; Nagai, Kazushige; Hirata, Yuichiro; Ozawa, Kunio; Mitsunobu, Satoshi; Kimura, Hiroyuki

2016-09-29

Accretionary prisms are mainly composed of ancient marine sediment scraped from the subducting oceanic plate at a convergent plate boundary. Large amounts of anaerobic groundwater and natural gas, mainly methane (CH4) and nitrogen gas (N2), are present in the deep aquifers associated with an accretionary prism; however, the origins of these gases are poorly understood. We herein revealed regional variations in CH4 and N2 production processes in deep aquifers in the accretionary prism in Southwest Japan, known as the Shimanto Belt. Stable carbon isotopic and microbiological analyses suggested that CH4 is produced through the non-biological thermal decomposition of organic matter in the deep aquifers in the coastal area near the convergent plate boundary, whereas a syntrophic consortium of hydrogen (H2)-producing fermentative bacteria and H2-utilizing methanogens contributes to the significant production of CH4 observed in deep aquifers in midland and mountainous areas associated with the accretionary prism. Our results also demonstrated that N2 production through the anaerobic oxidation of organic matter by denitrifying bacteria is particularly prevalent in deep aquifers in mountainous areas in which groundwater is affected by rainfall.

A survey of culturable aerobic and anaerobic marine bacteria in de novo biofilm formation on natural substrates in St. Andrews Bay, Scotland.

Science.gov (United States)

Finnegan, Lucy; Garcia-Melgares, Manuel; Gmerek, Tomasz; Huddleston, W Ryan; Palmer, Alexander; Robertson, Andrew; Shapiro, Sarah; Unkles, Shiela E

2011-10-01

This study reports a novel study of marine biofilm formation comprising aerobic and anaerobic bacteria. Samples of quartz and feldspar, minerals commonly found on the earth, were suspended 5 m deep in the North Sea off the east coast of St. Andrews, Scotland for 5 weeks. The assemblage of organisms attached to these stones was cultivated under aerobic and anaerobic conditions in the laboratory. Bacteria isolated on Marine Agar 2216 were all Gram-negative and identified to genus level by sequencing the gene encoding 16S rRNA. Colwellia, Maribacter, Pseudoaltermonas and Shewanella were observed in aerobically-grown cultures while Vibrio was found to be present in both aerobic and anaerobic cultures. The obligate anaerobic bacterium Psychrilyobacter atlanticus, a recently defined genus, was identified as a close relative of isolates grown anaerobically. The results provide valuable information as to the main players that attach and form de novo biofilms on common minerals in sea water.

Anaerobic Digestion and its Applications

Science.gov (United States)

Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

Science.gov (United States)

Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

2003-12-01

Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth

Long term behaviour of compacted argillite submitted to an alkaline fluid circulation

International Nuclear Information System (INIS)

Cuisinier, O.; Masrouri, F.; Deneele, Dimitri

2010-01-01

Document available in extended abstract form only. In the French concept of deep nuclear wastes repository, the galleries should be backfilled with excavated argillite after the site exploitation period. After several thousands of years, the degradation of the concrete lining of the galleries will generate alkaline fluid (pH > 12) that will diffuse through the backfill. The object of the study is to describe the influence of such solute diffusion on the microstructure of compacted argillite. Saturated-portlandite water was circulated through compacted samples for 3, 6 and 12 months at 20 or 60 deg. C. First, the mechanical behaviour of the samples was determined after the fluid circulation period. The microstructure of the samples was also analysed via mercury intrusion porosimetry tests, scanning electron microscopy and optical microscopy. Since it is planned to introduce additives (bentonite, calcareous sand or lime) in the remoulded argillite to backfill the deep galleries, such mixtures were also studied. The results showed that MA particles are sensitive to the alkaline fluid circulation at the microstructural level. In the case of the calcareous sand, no major changes of the microstructure nor the mechanical behaviour were observed. The pure argillite underwent slight modifications that can be related to a limited dissolution of its clayey particles. Conversely, intense alteration of the MX-80 particles was evidenced with a strong increase of the macro-pore void ration while the mechanical behaviour was slightly altered by the fluid circulation. Lime addition improved the mechanical characteristics of the argillite through the precipitation of cementitious compounds. The microstructure of the lime-treated argillite was also altered by the fluid circulation. That study evidenced that alkaline fluid circulation led to the dissolution clayey particles, leading to the increase of the macro-pore void ratio. Some of the dissolved compounds allowed the formation of

A One-compartment direct glucose alkaline fuel cell with methyl viologen as electron mediator

International Nuclear Information System (INIS)

Liu, Xianhua; Hao, Miaoqing; Feng, Mengnan; Zhang, Lin; Zhao, Yong; Du, Xiwen; Wang, Guangyi

2013-01-01

Highlights: ► A glucose–air alkaline fuel cell without using noble metal catalysts has been developed. ► The rudimentary fuel cell generates a maximum power density of 0.62 mW m −2 . ► The high performance is attributed to the use of MV and nickel foam. ► Main oxidation products are small organic acids indicating deep oxidation of glucose. - Abstract: Glucose is abundant, renewable, non-toxic and convenient as a fuel for fuel cells, but current technologies are unavailable for us to directly oxidize it to obtain energy. Fuel cells using enzymes and micro-organisms as catalysts are limited by their extremely low power output and rather short durability. Fuel cells using precious metal catalyst are expensive for large-scale use. In this work, a one-compartment direct glucose alkaline fuel cell has been developed that use methyl viologen (MV) as electron mediator and nickel foam as the anode. The rudimentary fuel cell generates a maximum power density of 0.62 mW cm −2 , while the maximum current density is 5.03 mA cm −2 . Electro-catalytic activities of MV and the nickel foam in alkaline conditions were studied by cyclic voltammetry. It is indicated that the high performance of the fuel cell is attributed to the combined use of MV and nickel foam. 13 C-NMR and HPLC were used to analyze oxidation products of glucose. The result shows that the principal oxidation products are short-chain organic acids indicating deep oxidation of glucose is achieved

Interannual sedimentary effluxes of alkalinity in the southern North Sea: model results compared with summer observations

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J. Pätsch

2018-06-01

Full Text Available For the sediments of the central and southern North Sea different sources of alkalinity generation are quantified by a regional modelling system for the period 2000–2014. For this purpose a formerly global ocean sediment model coupled with a pelagic ecosystem model is adapted to shelf sea dynamics, where much larger turnover rates than in the open and deep ocean occur. To track alkalinity changes due to different nitrogen-related processes, the open ocean sediment model was extended by the state variables particulate organic nitrogen (PON and ammonium. Directly measured alkalinity fluxes and those derived from Ra isotope flux observation from the sediment into the pelagic are reproduced by the model system, but calcite building and calcite dissolution are underestimated. Both fluxes cancel out in terms of alkalinity generation and consumption. Other simulated processes altering alkalinity in the sediment, like net sulfate reduction, denitrification, nitrification, and aerobic degradation, are quantified and compare well with corresponding fluxes derived from observations. Most of these fluxes exhibit a strong positive gradient from the open North Sea to the coast, where large rivers drain nutrients and organic matter. Atmospheric nitrogen deposition also shows a positive gradient from the open sea towards land and supports alkalinity generation in the sediments. An additional source of spatial variability is introduced by the use of a 3-D heterogenous porosity field. Due to realistic porosity variations (0.3–0.5 the alkalinity fluxes vary by about 4 %. The strongest impact on interannual variations of alkalinity fluxes is exhibited by the temporal varying nitrogen inputs from large rivers directly governing the nitrate concentrations in the coastal bottom water, thus providing nitrate necessary for benthic denitrification. Over the time investigated the alkalinity effluxes decrease due to the decrease in the nitrogen supply by the rivers.

Progress of research on the influence of alkaline cation and alkaline solution on bentonite properties

International Nuclear Information System (INIS)

Ye Weimin; Zheng Zhenji; Chen Bao; Chen Yonggui

2011-01-01

Based on the previous laboratory studies and numerical simulation on bentonite in alkaline environments, the effects of alkaline cation and alkaline solution on mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite are emphasized in this paper, temperature, pH values and concentration are discussed as main affecting factors. When bentonite is exposed to alkaline cation or alkaline solution, microstructure of bentonite will be changed due to the dissolution of montmorillonite and the formation of secondary minerals, which results in the decrease of swelling pressure. The amount of the reduction of swelling pressure depends on the concentration of alkaline solution. Temperature, polyvalent cation, salinity and concentration are the main factors affecting hydraulic properties of bentonite under alkaline conditions. Therefore, future research should focus on the mechanism of coupling effects of weak alkaline solutions on the mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite under different temperatures and different pH values. (authors)

Alkalinity in oil field waters - what alkalinity is and how it is measured

International Nuclear Information System (INIS)

Kaasa, B.; Oestvold, T.

1996-01-01

The alkalinity is an important parameter in the description of pH-behaviour, buffer capacity and scaling potentials in oil field waters. Although the alkalinity is widely used, it seems to be considerable confusion in connection with the concept. It is often used incorrectly and different authors define the concept in different ways. Several different methods for the determination of alkalinity can be found in the literature. This paper discusses the definition of alkalinity and how to use alkalinity in oil field waters to obtain data of importance for scale and pH predictions. There is also shown how a simple titration of oil field waters can give both the alkalinity and the content of organic acids in these waters. It is obvious from these findings that most of the methods used to day may give considerable errors when applied to oil field waters with high contents of organic acids. 8 refs., 8 figs., 5 tabs

[Current clinical significance of anaerobic bacteremia].

Science.gov (United States)

Jirsa, Roman; Marešová, Veronika; Brož, Zdeněk

2010-10-01

to estimate tje current clinical significance of anaerobic bacteremia in a group of Czech hospitals. this retrospective analysis comprised 8 444 anaerobic blood cultures in patients admitted to four Czech hospitals between 2004 and 2007. in 16 patients, blood cultures yielded significant anaerobic bacteria. Thus, anaerobic bacteremia accounted for less than 2 % of clinically significant bacteremia. Four patients (18 %) died but none of the deaths could be clearly attributable to anaerobic bacteria in the bloodstream. The most common comorbidities predisposing to anaerobic bacteremia and the most frequent sources of infection were similar to those reported by other authors. The majority of anaerobic bacteremia cases were due to gram-negative bacteria, followed by Clostridium perfringens and, surprisingly, Eubacterium spp. (particularly Eubacterium lentum). anaerobic bacteremia remains rare. The comparison of our data with those by other authors suggests that (despite the reported high mortality) the actual clinical significance of anaerobic bacteremia is rather controversial and that the anaerobic bacteremia might not correspond to more serious pathogenic role of the anaerobic bacteria as the source of infection.

Anaerobe Tolerance to Oxygen and the Potentials of Anaerobic and Aerobic Cocultures for Wastewater Treatment

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M.T. Kato

1997-12-01

Full Text Available The anaerobic treatment processes are considered to be well-established methods for the elimination of easily biodegradable organic matter from wastewaters. Some difficulties concerning certain wastewaters are related to the possible presence of dissolved oxygen. The common belief is that anaerobes are oxygen intolerant. Therefore, the common practice is to use sequencing anaerobic and aerobic steps in separate tanks. Enhanced treatment by polishing off the residual biodegradable oxygen demand from effluents of anaerobic reactors, or the biodegradation of recalcitrant wastewater pollutants, usually requires sequenced anaerobic and aerobic bacteria activities. However, the combined activity of both bacteria can also be obtained in a single reactor. Previous experiments with either pure or mixed cultures showed that anaerobes can tolerate oxygen to a certain extent. The oxygen toxicity to methanogens in anaerobic sludges was quantified in batch experiments, as well as in anaerobic reactors. The results showed that methanogens have a high tolerance to oxygen. In practice, it was confirmed that dissolved oxygen does not constitute any detrimental effect on reactor treatment performance. This means that the coexistence of anaerobic and aerobic bacteria in one single reactor is feasible and increases the potentials of new applications in wastewater treatment

Anaerobic Nitrogen Turnover by Sinking Diatom Aggregates at Varying Ambient Oxygen Levels

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Peter eStief

2016-02-01

Full Text Available In the world’s oceans, even relatively low oxygen (O2 levels inhibit anaerobic nitrogen cycling by free-living microbes. Sinking organic aggregates, however, might provide oxygen-depleted microbial hotspots in otherwise oxygenated surface waters. Here we show that sinking diatom aggregates can host anaerobic nitrogen cycling at ambient O2 levels well above the hypoxic threshold. Aggregates were produced from the ubiquitous diatom Skeletonema marinoi and the natural microbial community of seawater. Microsensor profiling through the center of sinking aggregates revealed internal anoxia at ambient 40% air saturation (~100 µmol O2 L-1 and below. Accordingly, anaerobic nitrate turnover inside the aggregates was evident within this range of ambient O2 levels. In incubations with 15N-labeled nitrate, individual Skeletonema aggregates produced NO2- (up to 10.7 nmol N h-1 per aggregate, N2 (up to 7.1 nmol N h-1, NH4+ (up to 2.0 nmol N h-1, and N2O (up to 0.2 nmol N h-1. Intriguingly, nitrate stored inside the diatom cells served as an additional, internal nitrate source for N2 production, which may partially uncouple anaerobic nitrate turnover by diatom aggregates from direct ambient nitrate supply. Sinking diatom aggregates can contribute directly to fixed-nitrogen loss in low-oxygen environments in the ocean and vastly expand the ocean volume in which anaerobic nitrogen turnover is possible, despite relatively high ambient O2 levels. Depending on the extent of intracellular nitrate consumption during the sinking process, diatom aggregates may also be involved in the long-distance export of nitrate to the deep ocean.

Effects of aerobic and anaerobic biological processes on leaching of heavy metals from soil amended with sewage sludge compost.

Science.gov (United States)

Fang, Wen; Wei, Yonghong; Liu, Jianguo; Kosson, David S; van der Sloot, Hans A; Zhang, Peng

2016-12-01

The risk from leaching of heavy metals is a major factor hindering land application of sewage sludge compost (SSC). Understanding the change in heavy metal leaching resulting from soil biological processes provides important information for assessing long-term behavior of heavy metals in the compost amended soil. In this paper, 180days aerobic incubation and 240days anaerobic incubation were conducted to investigate the effects of the aerobic and anaerobic biological processes on heavy metal leaching from soil amended with SSC, combined with chemical speciation modeling. Results showed that leaching concentrations of heavy metals at natural pH were similar before and after biological process. However, the major processes controlling heavy metals were influenced by the decrease of DOC with organic matter mineralization during biological processes. Mineralization of organic matter lowered the contribution of DOC-complexation to Ni and Zn leaching. Besides, the reducing condition produced by biological processes, particularly by the anaerobic biological process, resulted in the loss of sorption sites for As on Fe hydroxide, which increased the potential risk of As release at alkaline pH. Copyright © 2016 Elsevier Ltd. All rights reserved.

A laboratory study of anaerobic oxidation of methane in the presence of methane hydrate

Science.gov (United States)

Solem, R.; Bartlett, D.; Kastner, M.; Valentine, D.

2003-12-01

In order to mimic and study the process of anaerobic methane oxidation in methane hydrate regions we developed four high-pressure anaerobic bioreactors, designed to incubate environmental sediment samples, and enrich for populations of microbes associated with anaerobic methane oxidation (AMO). We obtained sediment inocula from a bacterial mat at the southern Hydrate Ridge, Cascadia, having cell counts approaching 1010 cells/cc. Ultimately, our goal is to produce an enriched culture of these microbes for characterization of the biochemical processes and chemical fluxes involved, as well as the unique adaptations required for, AMO. Molecular phylogenetic information along with results from fluorescent in situ hybridization indicate that consortia of Archaea and Bacteria are present which are related to those previously described for marine sediment AMO environments. Using a medium of enriched seawater and sediment in a 3:1 ratio, the system was incubated at 4° C under 43 atm of methane pressure; the temperature and pressure were kept constant. We have followed the reactions for seven months, particularly the vigorous consumption rates of dissolved sulfate and alkalinity production, as well as increases in HS-, and decreases in Ca concentrations. We also monitored the dissolved inorganic C (DIC) δ 13C values. The data were reproduced, and indicated that the process is extremely sensitive to changes in methane pressure. The rates of decrease in sulfate and increase in alkalinity concentrations were complimentary and showed considerable linearity with time. When the pressure in the reactor was decreased below the methane hydrate stability field, following the methane hydrate dissociation, sulfate reduction abruptly decreased. When the pressure was restored all the reactions returned to their previous rates. Much of the methane oxidation activity in the reactor is believed to occur in association with the methane hydrate. Upon the completion of one of the experiments

Vertical distribution and anaerobic biodegradation of polycyclic aromatic hydrocarbons in mangrove sediments in Hong Kong, South China

Energy Technology Data Exchange (ETDEWEB)

Li, Chun-Hua [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Zhou, Hong-Wei [Department of Environmental Health Science, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou (China); Wong, Yuk-Shan [Department of Biology, The Hong Kong University of Science and Technology (Hong Kong); Tam, Nora Fung-Yee, E-mail: bhntam@cityu.edu.hk [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2009-10-15

The vertical distribution of polycyclic aromatic hydrocarbons (PAHs) at different sediment depths, namely 0-2 cm, 2-4 cm, 4-6 cm, 6-10 cm, 10-15 cm and 15-20 cm, in one of the most contaminated mangrove swamps, Ma Wan, Hong Kong was investigated. It was the first time to study the intrinsic potential of deep sediment to biodegrade PAHs under anaerobic conditions and the abundance of electron acceptors in sediment for anaerobic degradation. Results showed that the total PAHs concentrations (summation of 16 US EPA priority PAHs) increased with sediment depth. The lowest concentration (about 1300 ng g{sup -1} freeze-dried sediment) and the highest value (around 5000 ng g{sup -1} freeze-dried sediment) were found in the surface layer (0-2 cm) and deeper layer (10-15 cm), respectively. The percentage of high molecular weight (HMW) PAHs (4 to 6 rings) to total PAHs was more than 89% at all sediment depths. The ratio of phenanthrene to anthracene was less than 10 while fluoranthene to pyrene was around 1. Negative redox potentials (Eh) were recorded in all of the sediment samples, ranging from - 170 to - 200 mv, with a sharp decrease at a depth of 6 cm then declined slowly to 20 cm. The results suggested that HMW PAHs originated from diesel-powered fishing vessels and were mainly accumulated in deep anaerobic sediments. Among the electron acceptors commonly used by anaerobic bacteria, sulfate was the most dominant, followed by iron(III), nitrate and manganese(IV) was the least. Their concentrations also decreased with sediment depth. The population size of total anaerobic heterotrophic bacteria increased with sediment depth, reaching the peak number in the middle layer (4-6 cm). In contrast, the aerobic heterotrophic bacterial count decreased with sediment depth. It was the first time to apply a modified electron transport system (ETS) method to evaluate the bacterial activities in the fresh sediment under PAH stress. The vertical drop of the ETS activity suggested that

Vertical distribution and anaerobic biodegradation of polycyclic aromatic hydrocarbons in mangrove sediments in Hong Kong, South China

International Nuclear Information System (INIS)

Li, Chun-Hua; Zhou, Hong-Wei; Wong, Yuk-Shan; Tam, Nora Fung-Yee

2009-01-01

The vertical distribution of polycyclic aromatic hydrocarbons (PAHs) at different sediment depths, namely 0-2 cm, 2-4 cm, 4-6 cm, 6-10 cm, 10-15 cm and 15-20 cm, in one of the most contaminated mangrove swamps, Ma Wan, Hong Kong was investigated. It was the first time to study the intrinsic potential of deep sediment to biodegrade PAHs under anaerobic conditions and the abundance of electron acceptors in sediment for anaerobic degradation. Results showed that the total PAHs concentrations (summation of 16 US EPA priority PAHs) increased with sediment depth. The lowest concentration (about 1300 ng g -1 freeze-dried sediment) and the highest value (around 5000 ng g -1 freeze-dried sediment) were found in the surface layer (0-2 cm) and deeper layer (10-15 cm), respectively. The percentage of high molecular weight (HMW) PAHs (4 to 6 rings) to total PAHs was more than 89% at all sediment depths. The ratio of phenanthrene to anthracene was less than 10 while fluoranthene to pyrene was around 1. Negative redox potentials (Eh) were recorded in all of the sediment samples, ranging from - 170 to - 200 mv, with a sharp decrease at a depth of 6 cm then declined slowly to 20 cm. The results suggested that HMW PAHs originated from diesel-powered fishing vessels and were mainly accumulated in deep anaerobic sediments. Among the electron acceptors commonly used by anaerobic bacteria, sulfate was the most dominant, followed by iron(III), nitrate and manganese(IV) was the least. Their concentrations also decreased with sediment depth. The population size of total anaerobic heterotrophic bacteria increased with sediment depth, reaching the peak number in the middle layer (4-6 cm). In contrast, the aerobic heterotrophic bacterial count decreased with sediment depth. It was the first time to apply a modified electron transport system (ETS) method to evaluate the bacterial activities in the fresh sediment under PAH stress. The vertical drop of the ETS activity suggested that the

Method of cleaning alkaline metal

International Nuclear Information System (INIS)

Kawakami, Yukio; Naito, Kesahiro; Iizawa, Katsuyuki; Nakasuji, Takashi

1981-01-01

Purpose: To prevent scattering of used sodium and aqueous alkaline solution when cleaning used sodium and metallic sodium adhering to equipment with an aqueous alkaline solution. Method: A sodium treating container is filled with an aqueous alkaline solution, and stainless steel gauze is sunk in the container. Equipment to be cleaned such as equipment with sodium adhering to it are retained under the gauze and are thus cleaned. On the other hand, the surface of the aqueous alkaline solution is covered with a fluid paraffin liquid covering material. Thus, the hydrogen produced by the reaction of the sodium and the aqueous alkaline solution will float up, pass through the liquid covering material and be discharged. The sodium will pass through the gauze and float upwardly while reacting with the aqueous alkaline solution in a partic ulate state to the boundary between the aqueous alkaline solution and up to the covering material, and thus the theratment reaction will continue. Thus, the cover material prevents the sodium and the aqueous alkaline solution from scattering. (Kamimura, M.)

Acetate biodegradation by anaerobic microorganisms at high pH and high calcium concentration

International Nuclear Information System (INIS)

Yoshida, Takahiro

2011-01-01

Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14 C compounds in cementitious repositories. Tamagawa river sediment or Teganuma pond sediment was anaerobically cultured with 5 mM acetate and 10 mM nitrate at pH 9.5-12 at 30 o C. After 20 and 90 days, the acetate concentration of the culture medium was analyzed and found to have decreased below 5 mM at pH ≤ 11. On the other hand, it did not decrease when either sediment was incubated in the absence of nitrate. These results suggest that nitrate-reducing bacteria can biodegrade acetate under more alkaline conditions than the reported pH range in which nitrate-reducing bacteria can exhibit activity. Acetate biodegradation was also examined at a high calcium concentration. Sediments were anaerobically cultured at pH 9.5 with 5 mM acetate and 10 mM nitrate in solution, equilibrated with ordinary Portland cement hydrate, in which the Ca concentration was 14.6 mM. No decrease in acetate concentration after incubation of the sediments was observed, nor was it lower than in the absence of cementitious composition, suggesting that kinetics of acetate biodegradation by anaerobic microorganisms is lowered by a high Ca concentration. - Research highlights: → Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14 C compounds in cementitious repositories. → Nitrate-reducing bacteria can biodegrade acetate at pH ≤ 11. → Kinetics of acetate biodegradation by anaerobic microorganisms might be lowered by a high Ca concentration.

Anaerobic treatment techniques

International Nuclear Information System (INIS)

Boehnke, B.; Bischofsberger, W.; Seyfried, C.F.

1993-01-01

This practical and theoretical guide presents the current state of knowledge in anaerobic treatment of industrial effluents with a high organic pollutant load and sewage sludges resulting from the treatment of municipal and industrial waste water. Starting from the microbiological bases of anaerobic degradation processes including a description and critical evaluation of executed plants, the book evolves the process-technical bases of anaerobic treatment techniques, derives relative applications, and discusses these with reference to excuted examples. (orig./UWA). 232 figs [de

Alkali-developable silicone-based negative photoresist (SNP) for deep UV, electron beam, and X-ray lithographies

International Nuclear Information System (INIS)

Ban, Hiroshi; Tanaka, Akinobu; Kawai, Yoshio; Deguchi, Kimiyoshi

1989-01-01

A new silicone-based negative photoresist (SNP) developable with alkaline aqueous solutions is prepared. SNP composed of acetylated phenylsilsesquioxane oligomer and azidopyrene is applied to deep UV, electron beam (EB), and X-ray lithographies. SNP slightly swells in alkaline developers, thus exhibiting exceptionally high resolution characteristics for a negative resist. The resistance of SNP to oxygen reactive ion etching is approximately 30 times greater than that of conventional novolac resists. (author)

Mechanical and Alkaline Hydrothermal Treated Corn Residue Conversion in to Bioenergy and Biofertilizer: A Resource Recovery Concept

Directory of Open Access Journals (Sweden)

Subhash Paul

2018-02-01

Full Text Available In this research fall time harvested corn residue (CR was first mechanically pretreated to produce 5 mm chopped and <500 µm ground particles, which underwent an anaerobic digestion (AD process to produce biomethane and biofertilizer. Another sample of CR was pretreated by an alkaline hydrothermal (HT process using 1%, 2% and 3% NaOH to produce solid biocarbon and the resulting alkaline hydrothermal process water (AHTPW, a co-product of biocarbon, underwent fast digestion under AD conditions to produce biomethane and biofertilizer. A predetermined HT process of 240 °C for 30 min was considered and the effect of alkali content on the HT process for biocarbon and biomethane product a rate of 8.21 MJ kg−1 and 9.23 MJ kg−1 of raw CR, respectively. Among the three selected alkaline HT processes, the 1% NaOH HT process produced the highest hybrid bioenergy of 11.39 MJ kg−1 of raw CR with an overall energy recovery of 62.82% of raw CR. The AHTPW of 2% and 3% NaOH HT-treated CR did not produce considerable amount of biomethane and their biocarbons contained 3.44 MJ kg−1 and 3.27 MJ kg−1 of raw CR of bioenergy, respectively. The biomethane produced from 5 mm chopped CR, <500 µm ground CR and 1% alkaline AHTPW for 30 days retention time were of 275.38 L kg−1 volatile solid (VS, 309.59 L kg−1 VS and 278.70 L kg−1 VS, respectively, compared to non-treated CR of 144–187 L kg−1 VS. Nutrient enriched AD digestate is useable as liquid fertilizer. Biocarbon, biomethane and biofertilizer produced from the 1% alkaline HT process at 240 °C for 30 min can reduce the greenhouse gas (GHG emissions of Ontario.

Anaerobic monodigestion of poultry manure: determination of operational parameters for CSTR.

Science.gov (United States)

Chamy, R; León, C; Vivanco, E; Poirrier, P; Ramos, C

2012-01-01

In this work the anaerobic monodigestion for the treatment of turkey manure was evaluated, without its codigestion with another substrate. The effect of the organic loading rate (OLR) and the substrate concentration (high total solids (TS) concentration) or product concentration (high volatile fatty acids (VFA) and/or ammonia (NH(3)-N) concentrations) was studied. The results show that for a continuous stirred tank reactor (CSTR) operation, a maximum of 40 g/L of TS and 4.0 g/L of ammonium (NH(4)(+)) was required. In addition, the maximum organic loading rate (OLR) will not exceed 1.5 kg VS/m(3)d. Higher TS and NH(4)(+) concentrations and OLR lead to a reduction on the methane productivity and volatile solids (VS) removal. During the CSTR operation, a high alkalinity concentration (above 10 g/L CaCO(3)) was found; this situation allowed maintaining a constant and appropriate pH (close to 7.8), despite the VFA accumulation. In this sense, the alkalinity ratio (α) is a more appropriate control and monitoring parameter of the reactor operation compared to pH. Additionally, with this parameter a VS removal of 80% with a methane productivity of 0.50 m(3)(CH4)/m(3)(R)d is achieved.

Natural analogues for expansion due to the anaerobic corrosion of ferrous materials

International Nuclear Information System (INIS)

Smart, N.R.; Adams, R.

2006-10-01

In Sweden, spent nuclear fuel will be encapsulated in sealed cylindrical canisters, consisting of a cast iron insert and a copper outer container. The canisters will be placed in a deep geologic repository and surrounded by bentonite. If a breach of the outer copper container were to occur the cast iron insert would undergo anaerobic corrosion, forming a magnetite film whose volume would be greater than that of the base metal. In principle there is a possibility that accumulation of iron corrosion product could cause expansion of the copper canister. Anaerobic corrosion rates are very slow, so in the work described in this report reference was made to analogous materials that had been corroding for long periods in natural anoxic aqueous environments. The report considers the types of naturally occurring environments that may give rise to anoxic environments similar to deep geological groundwater and where ferrous materials may be found. Literature information regarding the corrosion of iron archaeological artefacts is summarised and a number of specific archaeological artefacts containing iron and copper corroding in constrained geometries in anoxic natural waters are discussed in detail. No evidence was obtained from natural analogues which would suggest that severe damage is likely to occur to the SKB waste canister design as a result of expansive corrosion of cast iron under repository conditions

Natural analogues for expansion due to the anaerobic corrosion of ferrous materials

Energy Technology Data Exchange (ETDEWEB)

Smart, N.R.; Adams, R. [Serco Assurance, Culham Science Centre (United Kingdom)

2006-10-15

In Sweden, spent nuclear fuel will be encapsulated in sealed cylindrical canisters, consisting of a cast iron insert and a copper outer container. The canisters will be placed in a deep geologic repository and surrounded by bentonite. If a breach of the outer copper container were to occur the cast iron insert would undergo anaerobic corrosion, forming a magnetite film whose volume would be greater than that of the base metal. In principle there is a possibility that accumulation of iron corrosion product could cause expansion of the copper canister. Anaerobic corrosion rates are very slow, so in the work described in this report reference was made to analogous materials that had been corroding for long periods in natural anoxic aqueous environments. The report considers the types of naturally occurring environments that may give rise to anoxic environments similar to deep geological groundwater and where ferrous materials may be found. Literature information regarding the corrosion of iron archaeological artefacts is summarised and a number of specific archaeological artefacts containing iron and copper corroding in constrained geometries in anoxic natural waters are discussed in detail. No evidence was obtained from natural analogues which would suggest that severe damage is likely to occur to the SKB waste canister design as a result of expansive corrosion of cast iron under repository conditions.

Anaerobic ammonium oxidation by anammox bacteria in the Black Sea RID B-8834-2011

DEFF Research Database (Denmark)

Kuypers, MMM; Sliekers, AO; Lavik, G.

2003-01-01

The availability of fixed inorganic nitrogen (nitrate, nitrite and ammonium) limits primary productivity in many oceanic regions(1). The conversion of nitrate to N(2) by heterotrophic bacteria (denitrification) is believed to be the only important sink for fixed inorganic nitrogen in the ocean(2......). Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N(2) in the world's largest anoxic basin, the Black Sea. Phylogenetic analysis of 16S ribosomal RNA gene sequences shows that these bacteria are related to members of the order Planctomycetales performing...... the anammox (anaerobic ammonium oxidation) process in ammonium-removing bioreactors(3). Nutrient profiles, fluorescently labelled RNA probes, (15)N tracer experiments and the distribution of specific 'ladderane' membrane lipids(4) indicate that ammonium diffusing upwards from the anoxic deep water is consumed...

Combined (alkaline+ultrasonic) pretreatment effect on sewage sludge disintegration.

Science.gov (United States)

Kim, Dong-Hoon; Jeong, Emma; Oh, Sae-Eun; Shin, Hang-Sik

2010-05-01

The individual effects of alkaline (pH 8-13) and ultrasonic (3750-45,000kJ/kg TS) pretreatments on the disintegration of sewage sludge were separately tested, and then the effect of combining these two methods at different intensity levels was investigated using response surface methodology (RSM). In the combined pretreatment, ultrasonic treatment was applied to the alkali-pretreated sludge. While the solubilization (SCOD/TCOD) increase was limited to 50% in individual pretreatments, it reached 70% in combined pretreatment, and the results clearly showed that preconditioning of sludge at high pH levels played a crucial role in enhancing the disintegration efficiency of the subsequent ultrasonic pretreatment. By applying regression analysis, the disintegration degree (DD) was fitted based on the actual value to a second order polynomial equation: Y=-172.44+29.82X(1)+5.30x10(-3)X(2)-7.53x10(-5)X(1)X(2)-1.10X(1)(2)-1.043x10(-7)X(2)(2), where X(1), X(2), and Y are pH, specific energy input (kJ/kg TS), and DD, respectively. In a 2D contour plot describing the tendency of DD with respect to pH and specific energy input, it was clear that DD increased as pH increased, but it seemed that DD decreased when the specific energy input exceeded about 20,000kJ/kg TS. This phenomenon tells us that there exists a certain point where additional energy input is ineffective in achieving further disintegration. A synergetic disintegration effect was also found in the combined pretreatment, with lower specific energy input in ultrasonic pretreatment yielding higher synergetic effect. Finally, in order to see the combined pretreatment effect in continuous operation, the sludge pretreated with low intensity alkaline (pH 9)/ultrasonic (7500kJ/kg TS) treatment was fed to a 3 L of anaerobic sequencing batch reactor after 70 days of control operation. CH(4) production yield significantly increased from 81.9+/-4.5mL CH(4)/g COD(added) to 127.3+/-5.0mL CH(4)/g COD(added) by pretreatment, and

Mineralogical, petrological and geochemical aspects of alkaline and alkaline-carbonatite associations from Brazil

Science.gov (United States)

Morbidelli, L.; Gomes, C. B.; Beccaluva, L.; Brotzu, P.; Conte, A. M.; Ruberti, E.; Traversa, G.

1995-12-01

A general description of Mesozoic and Tertiary (Fortaleza) Brazilian alkaline and alkaline-carbonatite districts is presented with reference to mineralogy, petrology, geochemistry and geochronology. It mainly refers to scientific results obtained during the last decade by an Italo-Brazilian research team. Alkaline occurrences are distributed across Brazilian territory from the southern (Piratini, Rio Grande do Sul State) to the northeastern (Fortaleza, Ceará State) regions and are mainly concentrated along the borders of the Paraná Basin generally coinciding with important tectonic lineaments. The most noteworthy characteristics of these alkaline and alkaline-carbonatite suites are: (i) prevalence of intrusive forms; (ii) abundance of cumulate assemblages (minor dunites, frequent clinopyroxenites and members of the ijolite series) and (iii) abundance of evolved rock-types. Many data demonstrate that crystal fractionation was the main process responsible for magma evolution of all Brazilian alkaline rocks. A hypothesis is proposed for the genesis of carbonatite liquids by immiscibility processes. The incidence of REE and trace elements for different major groups of lithotypes, belonging both to carbonatite-bearing and carbonatite-free districts, are documented. Sr and preliminary Nd isotopic data are indicative of a mantle origin for the least evolved magmas of all the studied occurrences. Mantle source material and melting models for the generation of the Brazilian alkaline magma types are also discussed.

Clinical features of anaerobic orthopaedic infections.

Science.gov (United States)

Lebowitz, Dan; Kressmann, Benjamin; Gjoni, Shpresa; Zenelaj, Besa; Grosgurin, Olivier; Marti, Christophe; Zingg, Matthieu; Uçkay, Ilker

2017-02-01

Some patient populations and types of orthopaedic surgery could be at particular risk for anaerobic infections. In this retrospective cohort study of operated adult patients with infections from 2004 to 2014, we assessed obligate anaerobes and considered first clinical infection episodes. Anaerobes, isolated from intra-operative samples, were identified in 2.4% of 2740 surgical procedures, of which half (33/65; 51%) were anaerobic monomicrobial infections. Propionibacterium acnes, a penicillin and vancomycin susceptible pathogen, was the predominantly isolated anaerobe. By multivariate analysis, the presence of fracture fixation plates was the variable most strongly associated with anaerobic infection (odds ratio: 2.1, 95% CI: 1.3-3.5). Anaerobes were also associated with spondylodesis and polymicrobial infections. In contrast, it revealed less likely in native bone or prosthetic joint infections and was not related to prior antibiotic use. In conclusion, obligate anaerobes in our case series of orthopaedic infections were rare, and mostly encountered in infections related to trauma with open-fracture fixation devices rather than clean surgical site infection. Anaerobes were often co-pathogens, and cultures most frequently recovered P. acnes. These observations thus do not support changes in current practices such as broader anaerobe coverage for perioperative prophylaxis.

RISK FACTORS IN NEONATAL ANAEROBIC INFECTIONS

Directory of Open Access Journals (Sweden)

M. S. Tabib

2008-06-01

Full Text Available Anaerobic bacteria are well known causes of sepsis in adults but there are few studies regarding their role in neonatal sepsis. In an attempt to define the incidence of neonatal anaerobic infections a prospective study was performed during one year period. A total number of 400 neonates under sepsis study were entered this investigation. Anaerobic as well as aerobic cultures were sent. The patients were subjected to comparison in two groups: anaerobic culture positive and anaerobic culture negative and this comparison were analyzed statistically. There were 7 neonates with positive anaerobic culture and 35 neonates with positive aerobic culture. A significant statistical relationship was found between anaerobic infections and abdominal distention and pneumonia. It is recommended for those neonates with abdominal distention and pneumonia refractory to antibiotic treatment to be started on antibiotics with anaerobic coverage.

Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan)

NARCIS (Netherlands)

Felden, J.; Lichtschlag, A.; Wenzhöfer, F.; de Beer, D.; Feseker, T.; Pop Ristova, P.; de Lange, G.; Boetius, A.

2013-01-01

The Amon mud volcano (MV), located at 1250m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the

Fate of N-nitrosodimethylamine in recycled water after recharge into anaerobic aquifer.

Science.gov (United States)

Patterson, B M; Pitoi, M M; Furness, A J; Bastow, T P; McKinley, A J

2012-03-15

Laboratory and field experiments were undertaken to assess the fate of N-nitrosodimethylamine (NDMA) in aerobic recycled water that was recharged into a deep anaerobic pyritic aquifer, as part of a managed aquifer recharge (MAR) strategy. Laboratory studies demonstrated a high mobility of NDMA in the Leederville aquifer system with a retardation coefficient of 1.1. Anaerobic degradation column and (14)C-NDMA microcosm studies showed that anaerobic conditions of the aquifer provided a suitable environment for the biodegradation of NDMA with first-order kinetics. At microgram per litre concentrations, inhibition of biodegradation was observed with degradation half-lives (260±20 days) up to an order of magnitude greater than at nanogram per litre concentrations (25-150 days), which are more typical of environmental concentrations. No threshold effects were observed at the lower ng L(-1) concentrations with NDMA concentrations reduced from 560 ng L(-1) to recharge bore. These microcosm experiments showed a faster degradation rate than anaerobic microcosms, with a degradation half-life of 8±2 days, after a lag period of approximately 10 days. Results from a MAR field trial recharging the Leederville aquifer with aerobic recycled water showed that NDMA concentrations reduced from 2.5±1.0 ng L(-1) to 1.3±0.4 ng L(-1) between the recharge bore and a monitoring location 20 m down gradient (an estimated aquifer residence time of 10 days), consistent with data from the aerobic microcosm experiment. Further down gradient, in the anaerobic zone of the aquifer, NDMA degradation could not be assessed, as NDMA concentrations were too close to their analytical detection limit (<1 ng L(-1)). Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Aquatic macrophyte richness in Danish lakes in relation to alkalinity, transparency, and lake area

DEFF Research Database (Denmark)

Vestergaard, Ole Skafte; Sand-Jensen, Kaj

2000-01-01

We examined the relationship between environmental factors and the richness of submerged macrophytes species in 73 Danish lakes, which are mainly small, shallow, and have mesotrophic to hypertrophic conditions. We found that mean species richness per lake was only 4.5 in acid lakes of low...... alkalinity but 12.3 in lakes of high alkalinity due to a greater occurrence of the species-rich group of elodeids. Mean species richness per lake also increased significantly with increasing Secchi depth. No significant relationship between species richness and lake surface area was observed among the entire...... group of lakes or a subset of eutrophic lakes, as the growth of submerged macrophytes in large lakes may be restricted by wave action in shallow water and light restriction in deep water. In contrast, macrophyte species richness increased with lake surface area in transparent lakes, presumably due...

Simultaneous denitrification and anaerobic digestion in GRAnular Bed Baffled Reactor (GRABBR)

International Nuclear Information System (INIS)

Baloch, M.I.; Akunna, J.C.

2002-01-01

This study elucidates the characteristics of compartmentalised anaerobic system seeded with UASB granules, called GRAanular Bed Baffled Reactor (GRABBR), for combined denitrification and anaerobic digestion processes. The reactor was used for the treatment of glucose enriched synthetic wastewater with various nitrate concentrations. The study was carried out with a 10 litre working volume GRABBR divided into 5 equal compartments operating at organic loading rate (OLR) of 20 kg COD/m 3 .d with a hydraulic retention time (HRT) of 6 hours. At these conditions, phase separation (between acidogenesis and methanogenesis) was created in the system and then the effect of varying nitrate concentrations (50-200 mg/l NO 3 -N) in the acidogenic zone (i.e. first compartment) was studied. Due to its unique compartmentalised design, denitrification was the major pathway for nitrate reduction with no noticeable dissimilatory nitrate reduction to ammonia (DNRA). More than 84% of all added nitrates were removed in the acidogenic zone, showing that acidogens possess high denitrifying capabilities. The denitrification rate increased with increase in nitrate concentration, with maximum value estimated as 175 mg NO 3 -N/l.h at influent nitrate concentration of 200 mg/l NO 3 -N in the acidogenic zone. Although nitrate addition resulted in lower methane production, COD removal efficiencies improved by up to 8% when compared with the reactor performance before nitrate addition. Furthermore, the alkalinity produced during denitrification improved the stability of the system by controlling the decrease in pH resulting from acidogenesis. The system encouraged simultaneous denitrification and anaerobic digestion in a single unit by accommodating denitrifiers in the early compartments and allowing methanogenesis to flourish in the downstream compartments of the system, thus minimising inhibition to methane producing bacteria by nitrates. (author)

Selected Topics in Anaerobic Bacteriology.

Science.gov (United States)

Church, Deirdre L

2016-08-01

Alteration in the host microbiome at skin and mucosal surfaces plays a role in the function of the immune system, and may predispose immunocompromised patients to infection. Because obligate anaerobes are the predominant type of bacteria present in humans at skin and mucosal surfaces, immunocompromised patients are at increased risk for serious invasive infection due to anaerobes. Laboratory approaches to the diagnosis of anaerobe infections that occur due to pyogenic, polymicrobial, or toxin-producing organisms are described. The clinical interpretation and limitations of anaerobe recovery from specimens, anaerobe-identification procedures, and antibiotic-susceptibility testing are outlined. Bacteriotherapy following analysis of disruption of the host microbiome has been effective for treatment of refractory or recurrent Clostridium difficile infection, and may become feasible for other conditions in the future.

Anaerobic digestion of Chinese cabbage waste silage with swine manure for biogas production: batch and continuous study.

Science.gov (United States)

Kafle, Gopi Krishna; Bhattarai, Sujala; Kim, Sang Hun; Chen, Lide

2014-01-01

The aim of this study was to investigate the potential for anaerobic co-digestion of Chinese cabbage waste silage (CCWS) with swine manure (SM). Batch and continuous experiments were carried out under mesophilic anaerobic conditions (36-38°C). The batch test evaluated the effect of CCWS co-digestion with SM (SM: CCWS=100:0; 25:75; 33:67; 0:100, % volatile solids (VS) basis). The continuous test evaluated the performance of a single stage completely stirred tank reactor with SM alone and with a mixture of SM and CCWS. Batch test results showed no significant difference in biogas yield up to 25-33% of CCWS; however, biogas yield was significantly decreased when CCWS contents in feed increased to 67% and 100%. When testing continuous digestion, the biogas yield at organic loading rate (OLR) of 2.0 g VSL⁻¹ d⁻¹ increased by 17% with a mixture of SM and CCWS (SM:CCWS=75:25) (423 mL g⁻¹ VS) than with SM alone (361 mL g⁻¹ VS). The continuous anaerobic digestion process (biogas production, pH, total volatile fatty acids (TVFA) and TVFA/total alkalinity ratios) was stable when co-digesting SM and CCWS (75:25) at OLR of 2.0 g VSL⁻¹ d⁻¹ and hydraulic retention time of 20 days under mesophilic conditions.

Effect of ammoniacal nitrogen on one-stage and two-stage anaerobic digestion of food waste

International Nuclear Information System (INIS)

Ariunbaatar, Javkhlan; Scotto Di Perta, Ester; Panico, Antonio; Frunzo, Luigi; Esposito, Giovanni; Lens, Piet N.L.; Pirozzi, Francesco

2015-01-01

Highlights: • Almost 100% of the biomethane potential of food waste was recovered during AD in a two-stage CSTR. • Recirculation of the liquid fraction of the digestate provided the necessary buffer in the AD reactors. • A higher OLR (0.9 gVS/L·d) led to higher accumulation of TAN, which caused more toxicity. • A two-stage reactor is more sensitive to elevated concentrations of ammonia. • The IC 50 of TAN for the AD of food waste amounts to 3.8 g/L. - Abstract: This research compares the operation of one-stage and two-stage anaerobic continuously stirred tank reactor (CSTR) systems fed semi-continuously with food waste. The main purpose was to investigate the effects of ammoniacal nitrogen on the anaerobic digestion process. The two-stage system gave more reliable operation compared to one-stage due to: (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; and (iii) a higher conversion rate of organic substrate to biomethane. Also a small amount of biohydrogen was detected from the first stage of the two-stage reactor making this system attractive for biohythane production. As the digestate contains ammoniacal nitrogen, re-circulating it provided the necessary alkalinity in the systems, thus preventing an eventual failure by volatile fatty acids (VFA) accumulation. However, re-circulation also resulted in an ammonium accumulation, yielding a lower biomethane production. Based on the batch experimental results the 50% inhibitory concentration of total ammoniacal nitrogen on the methanogenic activities was calculated as 3.8 g/L, corresponding to 146 mg/L free ammonia for the inoculum used for this research. The two-stage system was affected by the inhibition more than the one-stage system, as it requires less alkalinity and the physically separated methanogens are more sensitive to inhibitory factors, such as ammonium and propionic acid

Endodontic pathogens causing deep neck space infections: clinical impact of different sampling techniques and antibiotic susceptibility.

Science.gov (United States)

Poeschl, Paul W; Crepaz, Valentina; Russmueller, Guenter; Seemann, Rudolf; Hirschl, Alexander M; Ewers, Rolf

2011-09-01

The aims of the present study were to compare microbial populations in patients suffering from deep neck space abscesses caused by primary endodontic infections by sampling the infections with aspiration or swabbing techniques and to determine the susceptibility rates of the isolated bacteria to commonly used antibiotics. A total of 89 patients with deep neck space abscesses caused by primary endodontic infections requiring extraoral incision and drainage under general anesthesia were included. Either aspiration or swabbing was used to sample microbial pus specimens. The culture of the microbial specimens and susceptibility testing were performed following standard procedures. A total of 142 strains were recovered from 76 patients. In 13 patients, no bacteria were found. The predominant bacteria observed were streptococci (36%), staphylococci (13%), Prevotella (8%), and Peptostreptococcus (6%). A statistically significant greater number of obligate anaerobes were found in the aspiration group. The majority of patients presented a mixed aerobic-anaerobic population of bacterial flora (62%). The antibiotic resistance rates for the predominant bacteria were 10% for penicillin G, 9% for amoxicillin, 0% for amoxicillin clavulanate, 24% for clindamycin, and 24% for erythromycin. The results of our study indicated that a greater number of anaerobes were found when sampling using the aspiration technique. Penicillin G and aminopenicillins alone are not always sufficient for the treatment of severe deep neck space abscesses; beta-lactamase inhibitor combinations are more effective. Bacteria showed significant resistant rates to clindamycin. Thus, its single use in penicillin-allergic patients has to be carefully considered. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

New perspectives in anaerobic digestion

DEFF Research Database (Denmark)

van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær

2001-01-01

The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern...... requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader...

Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

NARCIS (Netherlands)

Erşahin, M.E.

2015-01-01

Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become

Livestock Anaerobic Digester Database

Science.gov (United States)

The Anaerobic Digester Database provides basic information about anaerobic digesters on livestock farms in the United States, organized in Excel spreadsheets. It includes projects that are under construction, operating, or shut down.

Anaerobic granular sludge and biofilm reactors

DEFF Research Database (Denmark)

Skiadas, Ioannis V.; Gavala, Hariklia N.; Schmidt, Jens Ejbye

2003-01-01

by the immobilization of the biomass, which forms static biofilms, particle-supported biofilms, or granules depending on the reactor's operational conditions. The advantages of the high-rate anaerobic digestion over the conventional aerobic wastewater treatment methods has created a clear trend for the change......-rate anaerobic treatment systems based on anaerobic granular sludge and biofilm are described in this chapter. Emphasis is given to a) the Up-flow Anaerobic Sludge Blanket (UASB) systems, b) the main characteristics of the anaerobic granular sludge, and c) the factors that control the granulation process...

Optimization of pretreatment, process performance, mass and energy balance in the anaerobic digestion of Arachis hypogaea (Peanut) hull

International Nuclear Information System (INIS)

Dahunsi, S.O.; Oranusi, S.; Efeovbokhan, V.E.

2017-01-01

Highlights: • Biogas was maximally produced from the anaerobic digestion of peanut hull. • Thermo-alkaline pretreatment enhanced enormous biogas yield from the biomass. • The optimal condition for maximal biogas yield were established. • The digestate has great potentials for usage as biofertilizers/soil conditioner. • The pretreatment is economical by converting the gas to heat and electric energies. - Abstract: The potential of a major bioresource (Peanut hull) for biogas generation was evaluated. A sample was pretreated using combinations of mechanical and thermo-alkaline procedures using the Central Composite Design (CCD) for the optimization of the pretreatment temperature and time while another sample was treated without thermo-alkaline methods. The physico-chemical and microbial characteristics of the A. hypogaea hull and the rumen contents were carried out using standard methods. The actual biogas yields were 1739.20 m"3/kg TSfed and 1100.50 m"3/kg TSfed with desirability values of 91 and 100% for the pretreated and untreated experiments respectively. The methane and carbon dioxide content of biogas from both experiments as revealed by Gas chromatography were 61.5 ± 2.5%; 24 ± 1% and 51 ± 2%; 25 ± 2% respectively. The optimization of important process parameters in the anaerobic digestion were done using CCD of Response Surface Methodology (RSM) and the Artificial Neural Networks (ANNs) and the optimal values for each of the five major parameters optimized are as follows: Temperature = 30.00 °C, pH = 7.50, Retention time = 30.00 day, Total solids = 12.00 g/kg and Volatile solids = 4.00 g/kg. Taking these values into account, the predicted biogas yield for RSM was 1819.89 m"3/kg TSfed and 1743.6 m"3/kg TSfed for ANNs in the thermo-alkaline pretreated experiment. For the experiment without pretreatment, the RSM predicted yield was 1119.54 m"3/kg TSfed while that of ANNs was 1103.40 m"3/kg TSfed. In all there was a 38.5% increase in predicted

Understanding the impact of cationic polyacrylamide on anaerobic digestion of waste activated sludge.

Science.gov (United States)

Wang, Dongbo; Liu, Xuran; Zeng, Guangming; Zhao, Jianwei; Liu, Yiwen; Wang, Qilin; Chen, Fei; Li, Xiaoming; Yang, Qi

2018-03-01

Previous investigations showed that cationic polyacrylamide (cPAM), a flocculant widely used in wastewater pretreatment and waste activated sludge dewatering, deteriorated methane production during anaerobic digestion of sludge. However, details of how cPAM affects methane production are poorly understood, hindering deep control of sludge anaerobic digestion systems. In this study, the mechanisms of cPAM affecting sludge anaerobic digestion were investigated in batch and long-term tests using either real sludge or synthetic wastewaters as the digestion substrates. Experimental results showed that the presence of cPAM not only slowed the process of anaerobic digestion but also decreased methane yield. The maximal methane yield decreased from 139.1 to 86.7 mL/g of volatile suspended solids (i.e., 1861.5 to 1187.0 mL/L) with the cPAM level increasing from 0 to 12 g/kg of total suspended solids (i.e., 0-236.7 mg/L), whereas the corresponding digestion time increased from 22 to 26 d. Mechanism explorations revealed that the addition of cPAM significantly restrained the sludge solubilization, hydrolysis, acidogenesis, and methanogenesis processes. It was found that ∼46% of cAPM was degraded in the anaerobic digestion, and the degradation products significantly affected methane production. Although the theoretically biochemical methane potential of cPAM is higher than that of protein and carbohydrate, only 6.7% of the degraded cPAM was transformed to the final product, methane. Acrylamide, acrylic acid, and polyacrylic acid were found to be the main degradation metabolites, and their amount accounted for ∼50% of the degraded cPAM. Further investigations showed that polyacrylic acid inhibited all the solubilization, hydrolysis, acidogenesis, and methanogenesis processes while acrylamide and acrylic acid inhibited the methanogenesis significantly. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electrooxidation as the anaerobic pre-treatment of fats: oleate conversion using RuO2 and IrO2 based anodes.

Science.gov (United States)

Gonçalves, M; Alves, M M; Correia, J P; Marques, I P

2008-11-01

Electrochemical treatment of oleate using RuO2 and IrO2 type dimensionally stable anodes in alkaline medium was performed to develop a feasible anaerobic pre-treatment of fatty effluents. The results showed that the pre-treated solutions over RuO2 were faster degraded by anaerobic consortium than the raw oleate solutions or the electrolysed solutions using IrO2. In batch experiments carried out with pre-treated solutions over RuO2 (100-500mg/L), no lag phases were observed before the methane production onset. On the other hand, raw oleate and pre-treated oleate over IrO2 had originated lag phases of 0-140 and 0-210h, respectively. This study demonstrated that it is advantageous to apply the electrochemical treatment carried out on the RuO2 type DSA in order to achieve a faster biodegradation of lipid-containing effluent and consequently to obtain a faster methane production.

Detection of putatively thermophilic anaerobic methanotrophs in diffuse hydrothermal vent fluids.

Science.gov (United States)

Merkel, Alexander Y; Huber, Julie A; Chernyh, Nikolay A; Bonch-Osmolovskaya, Elizaveta A; Lebedinsky, Alexander V

2013-02-01

The anaerobic oxidation of methane (AOM) is carried out by a globally distributed group of uncultivated Euryarchaeota, the anaerobic methanotrophic arachaea (ANME). In this work, we used G+C analysis of 16S rRNA genes to identify a putatively thermophilic ANME group and applied newly designed primers to study its distribution in low-temperature diffuse vent fluids from deep-sea hydrothermal vents. We found that the G+C content of the 16S rRNA genes (P(GC)) is significantly higher in the ANME-1GBa group than in other ANME groups. Based on the positive correlation between the P(GC) and optimal growth temperatures (T(opt)) of archaea, we hypothesize that the ANME-1GBa group is adapted to thrive at high temperatures. We designed specific 16S rRNA gene-targeted primers for the ANME-1 cluster to detect all phylogenetic groups within this cluster, including the deeply branching ANME-1GBa group. The primers were successfully tested both in silico and in experiments with sediment samples where ANME-1 phylotypes had previously been detected. The primers were further used to screen for the ANME-1 microorganisms in diffuse vent fluid samples from deep-sea hydrothermal vents in the Pacific Ocean, and sequences belonging to the ANME-1 cluster were detected in four individual vents. Phylotypes belonging to the ANME-1GBa group dominated in clone libraries from three of these vents. Our findings provide evidence of existence of a putatively extremely thermophilic group of methanotrophic archaea that occur in geographically and geologically distinct marine hydrothermal habitats.

Economic viability of anaerobic digestion

Energy Technology Data Exchange (ETDEWEB)

Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

1996-01-01

The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

Uranium in alkaline rocks

Energy Technology Data Exchange (ETDEWEB)

Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

1978-04-01

Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

Uranium in alkaline rocks

International Nuclear Information System (INIS)

Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

1978-04-01

Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

Alkaline pH sensor molecules.

Science.gov (United States)

Murayama, Takashi; Maruyama, Ichiro N

2015-11-01

Animals can survive only within a narrow pH range. This requires continual monitoring of environmental and body-fluid pH. Although a variety of acidic pH sensor molecules have been reported, alkaline pH sensor function is not well understood. This Review describes neuronal alkaline pH sensors, grouped according to whether they monitor extracellular or intracellular alkaline pH. Extracellular sensors include the receptor-type guanylyl cyclase, the insulin receptor-related receptor, ligand-gated Cl- channels, connexin hemichannels, two-pore-domain K+ channels, and transient receptor potential (TRP) channels. Intracellular sensors include TRP channels and gap junction channels. Identification of molecular mechanisms underlying alkaline pH sensing is crucial for understanding how animals respond to environmental alkaline pH and how body-fluid pH is maintained within a narrow range. © 2015 Wiley Periodicals, Inc.

The Alkaline Diet: Is There Evidence That an Alkaline ph Diet Benefits Health?

International Nuclear Information System (INIS)

Schwalfenberg, G.K.

2012-01-01

This review looks at the role of an alkaline diet in health. Pub med was searched looking for articles on ph, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine

Anaerobic digestion performance of sweet potato vine and animal manure under wet, semi-dry, and dry conditions.

Science.gov (United States)

Zhang, Enlan; Li, Jiajia; Zhang, Keqiang; Wang, Feng; Yang, Houhua; Zhi, Suli; Liu, Guangqing

2018-03-22

Sweet potato vine (SPV) is an abundant agricultural waste, which is easy to obtain at low cost and has the potential to produce clean energy via anaerobic digestion (AD). The main objectives of this study were to reveal methane production and process stability of SPV and the mixtures with animal manure under various total solid conditions, to verify synergetic effect in co-digestion of SPV and manure in AD systems, and to determine the kinetics characteristics during the full AD process. The results showed that SPV was desirable feedstock for AD with 200.22 mL/g VS added of methane yield in wet anaerobic digestion and 12.20 L methane /L working volume in dry anaerobic digestion (D-AD). Synergistic effects were found in semi-dry anaerobic digestion and D-AD with each two mixing feedstock. In contrast with SPV mono-digestion, co-digestion with manure increased methane yield within the range of 14.34-49.11% in different AD digesters. The values of final volatile fatty acids to total alkalinity (TA) were below 0.4 and the values of final pH were within the range of 7.4-8.2 in all the reactors, which supported a positive relationship between carbohydrate hydrolysis and methanogenesis during AD process. The mathematical modified first order model was applied to estimate substrate biodegradability and methane production potential well with conversion constant ranged from 0.0003 to 0.0953 1/day, which indicated that co-digestion increased hydrolysis efficiency and metabolic activity. This work provides useful information to improve the utilization and stability of digestion using SPV and livestock or poultry manure as substrates.

Characterization and treatment of Denizli landfill leachate using anaerobic hybrid/aerobic CSTR systems.

Science.gov (United States)

Ağdağ, Osman Nuri

2011-01-01

Leachate generated in municipal solid waste landfill contains large amounts of organic and inorganic contaminants. In the scope of the study, characterization and anaerobic/aerobic treatability of leachate from Denizli (Turkey) Sanitary Landfill were investigated. Time-based fluctuations in characteristics of leachate were monitored during a one-year period. In characterization study; chemical oxygen demand (COD), biochemical oxygen demand (BOD) dissolved oxygen, temperature, pH, alkalinity, volatile fatty acids, total nitrogen, NH4-N, BOD5/COD ratio, suspended solid, inert COD, anaerobic toxicity assay and heavy metals concentrations in leachate were monitored. Average COD, BOD and NH4-N concentration in leachate were measured as 18034 mg/l, 11504 mg/l and 454 mg/l, respectively. Generally, pollution parameters in leachate were higher in summer and relatively lower in winter due to dilution by precipitation. For treatment of leachate, two different reactors, namely anaerobic hybrid and aerobic completely stirred tank reactor (CSTR) having effective volumes of 17.7 and 10.5 litres, respectively, were used. After 41 days of start-up period, leachate was loaded to hybrid reactor at 10 different organic loading rates (OLRs). OLR was increased by increasing COD concentrations. COD removal efficiency of hybrid reactor was carried out at a maximum of 91%. A percentage of 96% of residual COD was removed in the aerobic reactor. NH4-N removal rate in CSTR was quite high. In addition, high methane content was obtained as 64% in the hybrid reactor. At the end of the study, after 170 operation days, it can be said that the hybrid reactor and CSTR were very effective for leachate treatment.

Combination of Successive Alkalinity Producing System (SAPS) and Aeration for Passive Treatment of Highly Acidic Mine Drainage

Science.gov (United States)

Oh, C.; Ji, S.

2015-12-01

Passive treatment system has been widely used for remediation of mine drainage since its advantage of low installation and maintenance cost. The system, however, has also a disadvantage in assuring remediation and management efficiency if the drainage is highly acidic mine drainage. To remediate acid mine drainage (AMD) especially showing high acidity, passive treatment system which consists of successive alkalinity producing system (SAPS) and subsequent aeration pond was proposed and its mechanisms and efficiency was evaluated in this research. Target AMD was obtained from Waryong coal mine and showed typical characteristics of AMD having high metal concentration and low pH (acidity > 300 mg/L as CaCO3). Four experimental cases were conducted; untreated, treated with SAPS, treated with aeration, treated with SAPS and aeration to compare role and mechanism of each unit. Between organic matter and limestone layer which constitute SAPS, the former eliminated most of Fe(III) and Al in the AMD so that the latter was kept from being clogged by precipitates. Net acidity of the AMD rapidly decreased by supplement of alkalinity at the limestone layer. A primary function of SAPS, producing alkalinity constantly without clogging, was attained due to addition a portion of limestone particle into the organic matter layer. The discharge from SAPS had low ORP and DO values because of an anaerobic environment formed at the organic matter layer although its alkalinity was increased. This water quality was unfavorable for Fe(II) to be oxidized. Installation of aeration pond after SAPS, therefore, could be effective way of enhancing oxidation rate of Fe(II). Among the experimental cases, the combination of SAPS and aeration pond was only able to remediate the AMD. This concluded that to remediate highly acidic mine drainage with passive treatment system, three critical conditions were required; pre-precipitation of Fe(III) and Al at organic matter layer in SAPS, constant alkalinity

Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

Science.gov (United States)

Grübel, Klaudiusz; Suschka, Jan

2015-05-01

The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

Molecular ecology of anaerobic reactor systems

DEFF Research Database (Denmark)

Hofman-Bang, H. Jacob Peider; Zheng, D.; Westermann, Peter

2003-01-01

Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible for these ......Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible...... to the abundance of each microbe in anaerobic reactor systems by rRNA probing. This chapter focuses on various molecular techniques employed and problems encountered when elucidating the microbial ecology of anaerobic reactor systems. Methods such as quantitative dot blot/fluorescence in-situ probing using various...

Anaerobic bacteria as producers of antibiotics.

Science.gov (United States)

Behnken, Swantje; Hertweck, Christian

2012-10-01

Anaerobic bacteria are the oldest terrestrial creatures. They occur ubiquitously in soil and in the intestine of higher organisms and play a major role in human health, ecology, and industry. However, until lately no antibiotic or any other secondary metabolite has been known from anaerobes. Mining the genome sequences of Clostridium spp. has revealed a high prevalence of putative biosynthesis genes (PKS and NRPS), and only recently the first antibiotic from the anaerobic world, closthioamide, has been isolated from the cellulose degrading bacterium Clostridium cellulolyticum. The successful genetic induction of antibiotic biosynthesis in an anaerobe encourages further investigations of obligate anaerobes to tap their hidden biosynthetic potential.

Alkaline solution/binder ratio as a determining factor in the alkaline activation of aluminosilicates

Energy Technology Data Exchange (ETDEWEB)

Ruiz-Santaquiteria, C., E-mail: ruiz.cs@ietcc.csic.es [Eduardo Torroja Institute (CSIC), c/Serrano Galvache, n Degree-Sign 4, 28033 Madrid (Spain); Skibsted, J. [Instrument Centre for Solid-State NMR Spectroscopy, Interdisciplinary Nanoscience Center (iNANO), Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Fernandez-Jimenez, A.; Palomo, A. [Eduardo Torroja Institute (CSIC), c/Serrano Galvache, n Degree-Sign 4, 28033 Madrid (Spain)

2012-09-15

This study investigates the effect of the alkaline solution/binder (S/B) ratio on the composition and nanostructure of the reaction products generated in the alkaline activation of aluminosilicates. The experiments used two mixtures of fly ash and dehydroxylated white clay and for each of these, varying proportions of the solution components. The alkali activator was an 8 M NaOH solution (with and without sodium silicate) used at three S/B ratios: 0.50, 0.75 and 1.25. The {sup 29}Si, {sup 27}Al MAS NMR and XRD characterisation of the reaction products reveal that for ratios nearest the value delivering suitable paste workability, the reaction-product composition and structure depend primarily on the nature and composition of the starting materials and the alkaline activator used. However, when an excess alkaline activator is present in the system, the reaction products tend to exhibit SiO{sub 2}/Al{sub 2}O{sub 3} ratios of approximately 1, irrespective of the composition of the starting binder or the alkaline activator.

21 CFR 866.2120 - Anaerobic chamber.

Science.gov (United States)

2010-04-01

... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a device intended for medical purposes to maintain an anaerobic (oxygen...

pH and Organic Carbon Dose Rates Control Microbially Driven Bioremediation Efficacy in Alkaline Bauxite Residue.

Science.gov (United States)

Santini, Talitha C; Malcolm, Laura I; Tyson, Gene W; Warren, Lesley A

2016-10-18

Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H + produced per day with pH decreasing from 9.5 to ≤6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.

Hydrogenase-3 contributes to anaerobic acid resistance of Escherichia coli.

Science.gov (United States)

Noguchi, Ken; Riggins, Daniel P; Eldahan, Khalid C; Kitko, Ryan D; Slonczewski, Joan L

2010-04-12

Hydrogen production by fermenting bacteria such as Escherichia coli offers a potential source of hydrogen biofuel. Because H(2) production involves consumption of 2H(+), hydrogenase expression is likely to involve pH response and regulation. Hydrogenase consumption of protons in E. coli has been implicated in acid resistance, the ability to survive exposure to acid levels (pH 2-2.5) that are three pH units lower than the pH limit of growth (pH 5-6). Enhanced survival in acid enables a larger infective inoculum to pass through the stomach and colonize the intestine. Most acid resistance mechanisms have been defined using aerobic cultures, but the use of anaerobic cultures will reveal novel acid resistance mechanisms. We analyzed the pH regulation of bacterial hydrogenases in live cultures of E. coli K-12 W3110. During anaerobic growth in the range of pH 5 to 6.5, E. coli expresses three hydrogenase isoenzymes that reversibly oxidize H(2) to 2H(+). Anoxic conditions were used to determine which of the hydrogenase complexes contribute to acid resistance, measured as the survival of cultures grown at pH 5.5 without aeration and exposed for 2 hours at pH 2 or at pH 2.5. Survival of all strains in extreme acid was significantly lower in low oxygen than for aerated cultures. Deletion of hyc (Hyd-3) decreased anoxic acid survival 3-fold at pH 2.5, and 20-fold at pH 2, but had no effect on acid survival with aeration. Deletion of hyb (Hyd-2) did not significantly affect acid survival. The pH-dependence of H(2) production and consumption was tested using a H(2)-specific Clark-type electrode. Hyd-3-dependent H(2) production was increased 70-fold from pH 6.5 to 5.5, whereas Hyd-2-dependent H(2) consumption was maximal at alkaline pH. H(2) production, was unaffected by a shift in external or internal pH. H(2) production was associated with hycE expression levels as a function of external pH. Anaerobic growing cultures of E. coli generate H(2) via Hyd-3 at low external pH, and

Alkalinity of the Mediterranean Sea

OpenAIRE

Schneider, Anke; Wallace, Douglas W.R.; Körtzinger, Arne

2007-01-01

Total alkalinity (AT) was measured during the Meteor 51/2 cruise, crossing the Mediterranean Sea from west to east. AT concentrations were high (∼2600 μmol kg−1) and alkalinity-salinity-correlations had negative intercepts. These results are explained by evaporation coupled with high freshwater AT inputs into coastal areas. Salinity adjustment of AT revealed excess alkalinity throughout the water column compared to mid-basin surface waters. Since Mediterranean waters are supersaturated with r...

Environmental impacts of anaerobic digestion and the use of anaerobic residues as soil amendment

Energy Technology Data Exchange (ETDEWEB)

Mosey, F.E. [VFA Services Ltd., Herts (United Kingdom)

1996-01-01

This paper defines the environmental role of anaerobic digestion within the overall objective of recovering energy from renewable biomass resources. Examples and opportunities for incorporating anaerobic digestion into biomass-to-energy schemes are discussed, together with environmental aspects of anaerobic digestion plants. These include visual, public amenity, pathogens and public health, odor control, and gaseous emissions. Digestate disposal and the benefits of restrictions on recycling organic wastes and biomass residues back to the land are discussed, particularly as they relate to American and European codes of practice and environmental legislation. The paper concludes that anaerobic digestion, if performed in purpose-designed reactors that efficiently recover and use biogas, is an environmentally benign process that can enhance energy recovery and aid the beneficial land use of plant residues in many biomass-to-energy schemes.

Anaerobic treatment in Italy

Energy Technology Data Exchange (ETDEWEB)

Del Borghi, M; Solisio, C; Ferrailo, G

1984-02-01

In Italy, environmental protection and energy conservation have become very important since the increase in oil prices. The law requires that all waste waters have a B.O.D. of 40 mg/l by 1986 so there has been an expansion of purification plants since 1976, using anaerobic digestion. The report deals with the current state of anaerobic treatment in Italy with particular reference to (1) animal wastes. In intensive holdings, anaerobic digestion leads to a decrease in pollution and an increase in biogas generation which can be used to cover the energy demand of the process. The factors which influence the builders of digestors for farms are considered. (2) Non toxic industrial wastes. These are the waste waters emanating from the meat packing, brewing, pharmaceutical and chemical industries. Particular reference is made to the distillery plants using anaerobic treatment prior to aerobic digestion. (3) Urban wastes. The advantages and the disadvantages are considered and further research and development is recommended. 20 references.

Viscosity evolution of anaerobic granular sludge

NARCIS (Netherlands)

Pevere, A.; Guibaud, G.; Hullebusch, van E.D.; Lens, P.N.L.; Baudu, M.

2006-01-01

The evolution of the apparent viscosity at steady shear rate of sieved anaerobic granular sludge (20¿315 ¿m diameter) sampled from different full-scale anaerobic reactors was recorded using rotation tests. The ¿limit viscosity¿ of sieved anaerobic granular sludge was determined from the apparent

Anaerobic prosthetic joint infection.

Science.gov (United States)

Shah, Neel B; Tande, Aaron J; Patel, Robin; Berbari, Elie F

2015-12-01

In an effort to improve mobility and alleviate pain from degenerative and connective tissue joint disease, an increasing number of individuals are undergoing prosthetic joint replacement in the United States. Joint replacement is a highly effective intervention, resulting in improved quality of life and increased independence [1]. By 2030, it is predicted that approximately 4 million total hip and knee arthroplasties will be performed yearly in the United States [2]. One of the major complications associated with this procedure is prosthetic joint infection (PJI), occurring at a rate of 1-2% [3-7]. In 2011, the Musculoskeletal Infectious Society created a unifying definition for prosthetic joint infection [8]. The following year, the Infectious Disease Society of America published practice guidelines that focused on the diagnosis and management of PJI. These guidelines focused on the management of commonly encountered organisms associated with PJI, including staphylococci, streptococci and select aerobic Gram-negative bacteria. However, with the exception of Propionibacterium acnes, management of other anaerobic organisms was not addressed in these guidelines [1]. Although making up approximately 3-6% of PJI [9,10], anaerobic microorganisms cause devastating complications, and similar to the more common organisms associated with PJI, these bacteria also result in significant morbidity, poor outcomes and increased health-care costs. Data on diagnosis and management of anaerobic PJI is mostly derived from case reports, along with a few cohort studies [3]. There is a paucity of published data outlining factors associated with risks, diagnosis and management of anaerobic PJI. We therefore reviewed available literature on anaerobic PJI by systematically searching the PubMed database, and collected data from secondary searches to determine information on pathogenesis, demographic data, clinical features, diagnosis and management. We focused our search on five commonly

Microbial communities associated with the anthropogenic, highly alkaline environment of a saline soda lime, Poland.

Science.gov (United States)

Kalwasińska, Agnieszka; Felföldi, Tamás; Szabó, Attila; Deja-Sikora, Edyta; Kosobucki, Przemysław; Walczak, Maciej

2017-07-01

Soda lime is a by-product of the Solvay soda process for the production of sodium carbonate from limestone and sodium chloride. Due to a high salt concentration and alkaline pH, the lime is considered as a potential habitat of haloalkaliphilic and haloalkalitolerant microbial communities. This artificial and unique environment is nutrient-poor and devoid of vegetation, due in part to semi-arid, saline and alkaline conditions. Samples taken from the surface layer of the lime and from the depth of 2 m (both having pH ~11 and EC e up to 423 dS m -1 ) were investigated using culture-based (culturing on alkaline medium) and culture-independent microbiological approaches (microscopic analyses and pyrosequencing). A surprisingly diverse bacterial community was discovered in this highly saline, alkaline and nutrient-poor environment, with the bacterial phyla Proteobacteria (representing 52.8% of the total bacterial community) and Firmicutes (16.6%) showing dominance. Compared to the surface layer, higher bacterial abundance and diversity values were detected in the deep zone, where more stable environmental conditions may occur. The surface layer was dominated by members of the genera Phenylobacterium, Chelativorans and Skermanella, while in the interior layer the genus Fictibacillus was dominant. The culturable aerobic, haloalkaliphilic bacteria strains isolated in this study belonged mostly to the genus Bacillus and were closely related to the species Bacillus pseudofirmus, B. cereus, B. plakortidis, B. thuringensis and B. pumilus.

The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

Directory of Open Access Journals (Sweden)

Gerry K. Schwalfenberg

2012-01-01

Full Text Available This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine.

Effects of cellulose degradation products on the mobility of Eu(III) in repositories for low and intermediate level radioactive waste.

Science.gov (United States)

Diesen, Veronica; Forsberg, Kerstin; Jonsson, Mats

2017-10-15

The deep repository for low and intermediate level radioactive waste SFR in Sweden will contain large amounts of cellulosic waste materials contaminated with radionuclides. Over time the repository will be filled with water and alkaline conditions will prevail. In the present study degradation of cellulosic materials and the ability of cellulosic degradation products to solubilize and thereby mobilise Eu(III) under repository conditions has been investigated. Further, the possible immobilization of Eu(III) by sorption onto cement in the presence of degradation products has been investigated. The cellulosic material has been degraded under anaerobic and aerobic conditions in alkaline media (pH: 12.5) at ambient temperature. The degradation was followed by measuring the total organic carbon (TOC) content in the aqueous phase as a function of time. After 173days of degradation the TOC content is highest in the anaerobic artificial cement pore water (1547mg/L). The degradation products are capable of solubilising Eu(III) and the total europium concentration in the aqueous phase was 900μmol/L after 498h contact time under anaerobic conditions. Further it is shown that Eu(III) is adsorbed to the hydrated cement to a low extent (<9μmol Eu/g of cement) in the presence of degradation products. Copyright © 2017 Elsevier B.V. All rights reserved.

Atmospheric vs. anaerobic processing of metabolome samples for the metabolite profiling of a strict anaerobic bacterium, Clostridium acetobutylicum.

Science.gov (United States)

Lee, Sang-Hyun; Kim, Sooah; Kwon, Min-A; Jung, Young Hoon; Shin, Yong-An; Kim, Kyoung Heon

2014-12-01

Well-established metabolome sample preparation is a prerequisite for reliable metabolomic data. For metabolome sampling of a Gram-positive strict anaerobe, Clostridium acetobutylicum, fast filtration and metabolite extraction with acetonitrile/methanol/water (2:2:1, v/v) at -20°C under anaerobic conditions has been commonly used. This anaerobic metabolite processing method is laborious and time-consuming since it is conducted in an anaerobic chamber. Also, there have not been any systematic method evaluation and development of metabolome sample preparation for strict anaerobes and Gram-positive bacteria. In this study, metabolome sampling and extraction methods were rigorously evaluated and optimized for C. acetobutylicum by using gas chromatography/time-of-flight mass spectrometry-based metabolomics, in which a total of 116 metabolites were identified. When comparing the atmospheric (i.e., in air) and anaerobic (i.e., in an anaerobic chamber) processing of metabolome sample preparation, there was no significant difference in the quality and quantity of the metabolomic data. For metabolite extraction, pure methanol at -20°C was a better solvent than acetonitrile/methanol/water (2:2:1, v/v/v) at -20°C that is frequently used for C. acetobutylicum, and metabolite profiles were significantly different depending on extraction solvents. This is the first evaluation of metabolite sample preparation under aerobic processing conditions for an anaerobe. This method could be applied conveniently, efficiently, and reliably to metabolome analysis for strict anaerobes in air. © 2014 Wiley Periodicals, Inc.

Assessing the High Temperature, High Pressure Subsurface for Anaerobic Methane Oxidation

Science.gov (United States)

Harris, R. L.; Bartlett, D.; Byrnes, A. W.; Walsh, K. M.; Lau, C. Y. M.; Onstott, T. C.

2017-12-01

The anaerobic oxidation of methane (AOM) is an important sink in the global methane (CH4) budget. ANMEs are known to oxidize CH4 either independently or in consortia with bacteria, coupling the reduction of electron acceptors such as, SO42-, NO2-, NO3-, Mn4+, or Fe3+. To further constrain the contribution of AOM to the global CH4 budget, it is important to assess unexplored environments where AOM is thermodynamically possible such as the high pressure, high temperature deep biosphere. Provided plausible electron acceptor availability, increased temperature and pCH4 yield favorable Gibbs free energies for AOM reactions and the production of ATP (Fig. 1). To date, only sulfate-dependent AOM metabolism has been documented under high temperature conditions (50-72˚C), and AOM has not been assessed above 10.1 MPa. Given that ANMEs share close phylogenetic and metabolic heritage with methanogens and that the most heat-tolerant microorganism known is a barophilic methanogen, there possibly exist thermophilic ANMEs. Here we describe preliminary results from high pressure, high temperature stable isotope tracer incubation experiments on deep biosphere samples. Deep sub-seafloor sediments collected by IODP 370 from the Nankai Trough (257 - 865 m below seafloor) and deep fracture fluid from South Africa (1339 m below land surface) were incubated anaerobically in hydrostatic pressure vessels at 40 MPa in simulated in situ temperatures (40˚ - 80˚C). Sediments and fracture fluid were incubated in sulfate-free artificial seawater, a 2:98 13CH4:N2 headspace, and treated with one of the potential electron acceptors listed above in addition to kill and endogenous activity (i.e. no added electron acceptor) controls. Stable isotope analysis of dissolved inorganic carbon (DIC) suggests that AOM occurred within 60 days of incubation for all investigated electron acceptors and temperatures except 50˚C. Sulfate-dependent AOM rates are consistent with those previously reported in the

Determination of Acidity and Alkalinity of Food Materials

OpenAIRE

三浦,芳助; 福永,祐子; 瀧川,裕里子; 津田,真美; 渡辺,陽子; 瀨山,一正

2006-01-01

The acidity and alkalinity of food materials in various menus was determined to clarify the influence of food on physiological functions.　Menus mainly containing alkaline food materials (alkaline menu) and acid ones (acid menu) were compared.　Determination of acidity and alkalinity was performed for each food material in the alkaline menu and acid menu, and acidity and alkalinity of one meal and a day's one were estimated. １.　Most of food materials in acid menu were assessed to be...

Simple and convenient method for culturing anaerobic bacteria.

OpenAIRE

Behbehani, M J; Jordan, H V; Santoro, D L

1982-01-01

A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.

Microbial gene functions enriched in the Deepwater Horizon deep-sea oil plume

Energy Technology Data Exchange (ETDEWEB)

Lu, Z.; Deng, Y.; Nostrand, J.D. Van; He, Z.; Voordeckers, J.; Zhou, A.; Lee, Y.-J.; Mason, O.U.; Dubinsky, E.; Chavarria, K.; Tom, L.; Fortney, J.; Lamendella, R.; Jansson, J.K.; D?haeseleer, P.; Hazen, T.C.; Zhou, J.

2011-06-15

The Deepwater Horizon oil spill in the Gulf of Mexico is the deepest and largest offshore spill in U.S. history and its impacts on marine ecosystems are largely unknown. Here, we showed that the microbial community functional composition and structure were dramatically altered in a deep-sea oil plume resulting from the spill. A variety of metabolic genes involved in both aerobic and anaerobic hydrocarbon degradation were highly enriched in the plume compared to outside the plume, indicating a great potential for intrinsic bioremediation or natural attenuation in the deep-sea. Various other microbial functional genes relevant to carbon, nitrogen, phosphorus, sulfur and iron cycling, metal resistance, and bacteriophage replication were also enriched in the plume. Together, these results suggest that the indigenous marine microbial communities could play a significant role in biodegradation of oil spills in deep-sea environments.

Confirmation of the applicability of low alkaline cement-based material in the Horonobe Underground Research Laboratory

International Nuclear Information System (INIS)

Nakayama, Masashi; Niunoya, Sumio; Minamide, Masashi

2016-01-01

In Japan, high-level radioactive waste repository will be constructed in a stable host rock formation more than 300 m underground. Tunnel support is used for safety during the construction and operation, so, shotcrete and concrete lining are used as the tunnel support. Concrete is a composite material comprised of aggregate, cement, water and various additives. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. Japan Atomic Energy Agency (JAEA) has developed the low alkaline cement, named as HFSC (Highly fly-ash contained silicafume cement), containing over 60wt% of silicafume (SF) and Fly-ash (FA). JAEA is presently constructing the underground research laboratory (URL) at Horonobe for research and development in the geosciences and repository engineering technology. HFSC was used experimentally as the shotcrete material in construction of part of the 350 m deep gallery in the Horonobe URL in 2013. The objective of this experiment was to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. HFSC used in this experiment is composed of 40wt% OPC (Ordinary Portland Cement), 20wt% SF, and 40wt% FA. This composition was determined based on mechanical testing of various mixes of the above components. Because of the low OPC content, the strength of HFSC tends to be lower than that of OPC in normal concrete. The total length of tunnel constructed using HFSC shotcrete is about 112 m at 350 m deep drift. The workability of HFSC shotcrete was confirmed by this experimental construction. In this report, we present detailed results of the in-situ construction test. (author)

Inhibition of Anaerobic Biological Treatment: A Review

Science.gov (United States)

Hou, Li; Ji, Dandan; Zang, Lihua

2018-01-01

Anaerobic digestion is a method for treating living and industrial wastewater by anaerobic degradation of organic compounds, which can produce biogas (carbon dioxide and methane mixture) and microbial biomass. And biogas as a renewable resource, can replace the use of ore fuel. In the process of anaerobic digestion, the problems of low methane yield and unstable reaction process are often encountered, which limits the widespread use of this technology. Various inhibitors are the main limiting factors for anaerobic digestion. In this paper, the main factors limiting anaerobic digestion are reviewed, and the latest research progress is introduced.

Analysis of anaerobic blood cultures in burned patients.

Science.gov (United States)

Regules, Jason A; Carlson, Misty D; Wolf, Steven E; Murray, Clinton K

2007-08-01

The utility of anaerobic blood culturing is often debated in the general population, but there is limited data on the modern incidence, microbiology, and utility of obtaining routine anaerobic blood cultures for burned patients. We performed a retrospective review of the burned patients electronic medical records database for all blood cultures drawn between January 1997 and September 2005. We assessed blood cultures for positivity, organisms identified, and growth in aerobic or anaerobic media. 85,103 blood culture sets were drawn, with 4059 sets from burned patients. Three hundred and forty-five single species events (619 total blood culture isolates) were noted in 240 burned patients. For burned patients, four isolates were obligate anaerobic bacteria (all Propionibacterium acnes). Anaerobic versus aerobic culture growth was recorded in 310 of 619 (50.1%) burned patient blood culture sets. 46 (13.5%) of the identified organisms, most of which were not obligate anaerobic bacteria, were identified from solely anaerobic media. The results of our study suggest that the detection of significant anaerobic bacteremia in burned patients is very rare and that anaerobic bottles are not needed in this population for that indication. However anaerobic blood cultures systems are also able to detect facultative and obligate aerobic bacteria; therefore, the deletion of the anaerobic culture medium may have deleterious clinical impact.

Alkaline earth metals

International Nuclear Information System (INIS)

Brown, Paul L.; Ekberg, Christian

2016-01-01

The beryllium ion has a relatively small ionic radius. As a consequence of this small size, its hydrolysis reactions begin to occur at a relatively low pH. To determine the stability and solubility constants, however, the Gibbs energy of the beryllium ion is required. In aqueous solution calcium, like the other alkaline earth metals, only exists as a divalent cation. The size of the alkaline earth cations increases with increasing atomic number, and the calcium ion is bigger than the magnesium ion. The hydrolysis of barium(II) is weaker than that of strontium(II) and also occurs in quite alkaline pH solutions, and similarly, only the species barium hydroxide has been detected. There is only a single experimental study on the hydrolysis of radium. As with the stability constant trend, it would be expected that the enthalpy of radium would be lower than that of barium due to the larger ionic radius.

Effects of Physico-Chemical Post-Treatments on the Semi-Continuous Anaerobic Digestion of Sewage Sludge

Directory of Open Access Journals (Sweden)

Xinbo Tian

2017-07-01

Full Text Available Sludge production in wastewater treatment plants is increasing worldwide due to the increasing population. This work investigated the effects of ultrasonic (ULS, ultrasonic-ozone (ULS-Ozone and ultrasonic + alkaline (ULS+ALK post-treatments on the anaerobic digestion of sewage sludge in semi-continuous anaerobic reactors. Three conditions were tested with different hydraulic retention times (HRT, 10 or 20 days and sludge recycle ratios (R = QR/Qin (%: 50 or 100%. Biogas yield increased by 17.8% when ULS+ALK post-treatment was applied to the effluent of a reactor operating at 20 days HRT and at a 100% recycle ratio. Operation at 10 days HRT also improved the biogas yield (277 mL CH4/g VSadded (VS: volatile solids versus 249 mL CH4/g VSadded in the control. The tested post-treatment methods showed 4–7% decrease in effluent VS. The post-treatment resulted in a decrease in the cellular ATP (Adenosine tri-phosphate concentration indicating stress imposed on microorganisms in the reactor. Nevertheless, this did not prevent higher biogas production. Based on the results, the post-treatment of digested sludge or treating the sludge between two digesters is an interesting alternative to pre-treatments.

Hydraulic retention time on vinasse stabilisation with limestone in the acidogenic phase of anaerobic digestion

Directory of Open Access Journals (Sweden)

Ismael Plácido Tomielis

Full Text Available ABSTRACT: The main problem in anaerobic digestion of low-protein residues is the instability caused acidity. The use of limestone at the same time as a neutralizing agent and support material is innovative because stones wear allows the slow release of the calcium carbonate thereby eliminating dispersers. Free calcium content in the system was measured in two plug flow reactors filled with vinasse at initial pH of 4.50. The proportion of 1.8 tonnes of limestone per m³ of vinasse was evaluated at the Hydraulic Retention Times (HRT of 24, 48, 72, 96 and 120 hours, allowing stabilisation at 96 hours. The ratio of Volatile Acids/Total Alkalinity (VA/TA ranged from 0.2 to 0.4 and the pH reached 7.0, at the HRT of 120 hours. Increasing the HRT also increased the volatile total solids (VTS and fixed total solids (TFS in a similar profile to the measured free calcium content, but calcium remained at the appropriate level of 100 to 250mg l-1. The proportion of limestone/vinasse was adequate to ensure stabilisation, but it is not recommended to reduce the HRT below 96 hours due to the risk of compromising the stability of the anaerobic system.

Molecular genetic studies on obligate anaerobic bacteria

International Nuclear Information System (INIS)

Woods, D.R.

1982-01-01

Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

Anaerobic biological treatment

International Nuclear Information System (INIS)

Speece, R.E.

1990-01-01

The Enso-Fenox process has been very successfully used to remove chlorinated phenolic compounds from pulp bleaching effluents. It is a two-stage anaerobic/aerobic process consisting of a nonmethanogenic anaerobic fluidized bed followed by a trickling filter. Studies have been conducted on reductive dechlorination of chlorinated aromatic compounds under anaerobic conditions with chlorinated phenols as the sole carbon and energy source. Approximately 40% of the added chlorophenols was converted to CH 4 and CO 2 . Substrate loading rates were 20 mg/L/d at hydraulic detention times of 2-4 days with 90% substrate conversion efficiency. Reductive dechlorination of mono, di-, tri-, and pentachlorophenols has been demonstrated in anaerobic sewage sludge. The following constituents were tested in the laboratory at their approximate concentrations in coal conversion wastewater (CCWW) and were anaerobically degraded in serum bottles: 1,000 mg/L phenol; 500 mg/L resorcinol; 1,000 mg/L benzoic acid; 500 mg/L p-cresol; 200 mg/L pyridine; 2,000 mg/L benzoic acid; 250 mg/L 40 methylcatechol; 500 mg/L 4-ethylpyridine; and 2,000 mg/L hexanoic acid. A petrochemical may initially exhibit toxicity to an unacclimated population of methane-fermenting bacteria, but with acclimation the toxicity may be greatly reduced or disappear. In addition, the microorganisms may develop the capacity to actually degrade compounds which showed initial toxicity. Since biomass digestion requires a complete consortium of bacteria, it is relevant to study the effect of a given process as well as to individual steps within the process. A toxicant can inhibit the rate-limiting step and/or change the step that is rate-limiting. Both manifestations of toxicity can severely affect the overall process

Microbial diversity in methane hydrate-bearing deep marine sediments core preserved in the original pressure.

Science.gov (United States)

Takahashi, Y.; Hata, T.; Nishida, H.

2017-12-01

In normal coring of deep marine sediments, the sampled cores are exposed to the pressure of the atmosphere, which results in dissociation of gas-hydrates and might change microbial diversity. In this study, we analyzed microbial composition in methane hydrate-bearing sediment core sampled and preserved by Hybrid-PCS (Pressure Coring System). We sliced core into three layers; (i) outside layer, which were most affected by drilling fluids, (ii) middle layer, and (iii) inner layer, which were expected to be most preserved as the original state. From each layer, we directly extracted DNA, and amplified V3-V4 region of 16S rRNA gene. We determined at least 5000 of nucleotide sequences of the partial 16S rDNA from each layer by Miseq (Illumina). In the all layers, facultative anaerobes, which can grow with or without oxygen because they can metabolize energy aerobically or anaerobically, were detected as majority. However, the genera which are often detected anaerobic environment is abundant in the inner layer compared to the outside layer, indicating that condition of drilling and preservation affect the microbial composition in the deep marine sediment core. This study was conducted as a part of the activity of the Research Consortium for Methane Hydrate Resources in Japan [MH21 consortium], and supported by JOGMEC (Japan Oil, Gas and Metals National Corporation). The sample was provided by AIST (National Institute of Advanced Industrial Science and Technology).

Anaerobes in bacterial vaginosis

Directory of Open Access Journals (Sweden)

Aggarwal A

2003-01-01

Full Text Available Four hundred high vaginal swabs were taken from patients attending gynaecology and obstetrics department of Govt. medical college, Amritsar. The patients were divided into four groups i.e. women in pregnancy (Group I, in labour/post partum (Group II, with abnormal vaginal discharge or bacterial vaginosis (Group III and asymptomatic women as control (Group IV. Anaerobic culture of vaginal swabs revealed that out of 400 cases, 212(53% were culture positive. Maximum isolation of anaerobes was in group III (84% followed by group II (56%, group I (36% and control group (15%. Gram positive anaerobes (69.2% out numbered gram negatives (30.8%. Among various isolates Peptostreptococcus spp. and Bacteroides spp. were predominant.

Deep Conversion of Carbon Monoxide to Hydrogen and Formation of Acetate by the Anaerobic Thermophile Carboxydothermus hydrogenoformans

OpenAIRE

Henstra, Anne M.; Stams, Alfons J. M.

2011-01-01

Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial catalytic processes, makes this organism an interesting alternative for production of cheap hydrogen gas suitable to fuel CO-sensitive fuel cells in a future hydrogen economy, provided sufficiently lo...

Bicarbonate dosing: a tool to performance recovery of a thermophilic methanol-fed UASB reactor

NARCIS (Netherlands)

Paulo, P.L.; Lier, van J.B.; Lettinga, G.

2003-01-01

The thermophilic-anaerobic treatment of methanol-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor, was found to be quite sensitive to pH shocks, both acid and alkaline. The results of the recovery experiments of sludge exposed to an alkaline shock, indicated that the

Effect of inoculum-substrate ratio on acclimatization of pharmaceutical effluent in an anaerobic batch reactor.

Science.gov (United States)

Muruganandam, B; Saravanane, R; Lavanya, M; Sivacoumar, R

2008-07-01

Anaerobic treatment has gained tremendous success over the past two decades for treatment of industrial effluents. Over the past 30 years, the popularity of anaerobic wastewater treatment has increased as public utilities and industries have utilized its considerable benefits. Low biomass production, row nutrient requirements and the energy production in terms of methane yield are the significant advantages over aerobic treatment process. Due to the disadvantages reported in the earlier investigations, during the past decade, anaerobic biotechnology now seems to become a stable process technology in respect of generating a high quality effluent. The objective of the present experimental study was to compare the biodegradability of recalcitrant effluent (pharmaceutical effluent) for various inoculum-substrate ratios. The batch experiments were conducted over 6 months to get effect of ratio of inoculum-substrate on the acclimatization of pharmaceutical effluent. The tests were carried out in batch reactors, serum bottles, of volume 2000 mL and plastic canes of 10000 mL. Each inoculum was filled with a cow dung, sewage and phosphate buffer. The batch was made-up of diluted cow dung at various proportions of water and cow dung, i.e., 1:1 and 1:2 (one part of cow dung and one part of water by weight for 1:1). The bottles were incubated at ambient temperature (32 degrees C-35 degrees C). The bottles were closed tightly so that the anaerobic condition is maintained. The samples were collected and biodegradability was measured once in four days. The bottles were carefully stirred before gas measurement. The substrate was added to a mixture of inoculum and phosphate nutrients. The variations in pH, conductivity, alkalinity, COD, TS, TVS, VSS, and VFA were measured for batch process. The biogas productivity was calculated for various batches of inoculum-substrate addition and conclusions were drawn for expressing the biodegradability of pharmaceutical effluent on

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor.

Science.gov (United States)

Elmitwalli, Tarek A; Otterpohl, Ralf

2007-03-01

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30 degrees C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52-64% was obtained at HRT between 6 and 16 h. The UASB reactor removed 22-30% and 15-21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0.18 and 0.28 kg COD/(kg VS d).

Isolation and Cultivation of Anaerobes

DEFF Research Database (Denmark)

Aragao Börner, Rosa

2016-01-01

Anaerobic microorganisms play important roles in different biotechnological processes. Their complex metabolism and special cultivation requirements have led to less isolated representatives in comparison to their aerobic counterparts.In view of that, the isolation and cultivation of anaerobic...

Volatile Fatty Acids Production from Codigestion of Food Waste and Sewage Sludge Based on β-Cyclodextrins and Alkaline Treatments.

Science.gov (United States)

Yang, Xue; Liu, Xiang; Chen, Si; Liu, Guangmin; Wu, Shuyan; Wan, Chunli

2016-01-01

Volatile fatty acids (VFAs) are preferred valuable resources, which can be produced from anaerobic digestion process. This study presents a novel technology using β -cyclodextrins ( β -CD) pretreatment integrated alkaline method to enhance VFAs production from codigestion of food waste and sewage sludge. Experiment results showed that optimized ratio of food waste to sewage sludge was 3 : 2 because it provided adequate organic substance and seed microorganisms. Based on this optimized ratio, the integrated treatment of alkaline pH 10 and β -CD addition (0.2 g/g TS) performed the best enhancement on VFAs production, and the maximum VFAs production was 8631.7 mg/L which was 6.13, 1.38, and 1.57 times higher than that of control, initial pH 10, and 0.2 g β -CD/g TS treatment, respectively. Furthermore, the hydrolysis rate of protein and polysaccharides was greatly improved in integration treatment, which was 1.18-3.45 times higher than that of other tests. Though the VFAs production and hydrolysis of polymeric organics were highly enhanced, the primary bacterial communities with different treatments did not show substantial differences.

The phenomenon of granulation of anaerobic sludge

NARCIS (Netherlands)

Hulshoff Pol, L.

1989-01-01

Successful high-rate anaerobic wastewater treatment can only be accomplished when the slowgrowing anaerobic biomass is efficiently held back in the anaerobic treatment system. This biomass retention can be achieved in various ways including immobilization of the organisms on fixed materials

A simple and sensitive quality control method of the anaerobic atmosphere for identification and antimicrobial susceptibility testing of anaerobic bacteria

DEFF Research Database (Denmark)

Justesen, Tage; Justesen, Ulrik Stenz

2013-01-01

The maintenance of a strict anaerobic atmosphere is essential for the culture of strict anaerobic bacteria. We describe a simple and sensitive quality control method of the anaerobic atmosphere, based on the measurement of the zone diameter around a 5-μg metronidazole disk when testing...... an aerotolerant Clostridium perfringens strain. A zone diameter above 27 mm was indicative of acceptable anaerobic conditions....

Effect of ammoniacal nitrogen on one-stage and two-stage anaerobic digestion of food waste

Energy Technology Data Exchange (ETDEWEB)

Ariunbaatar, Javkhlan, E-mail: jaka@unicas.it [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Scotto Di Perta, Ester [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy); Panico, Antonio [Telematic University PEGASO, Piazza Trieste e Trento, 48, 80132 Naples (Italy); Frunzo, Luigi [Department of Mathematics and Applications Renato Caccioppoli, University of Naples Federico II, Via Claudio, 21, 80125 Naples (Italy); Esposito, Giovanni [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); Lens, Piet N.L. [UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Pirozzi, Francesco [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy)

2015-04-15

Highlights: • Almost 100% of the biomethane potential of food waste was recovered during AD in a two-stage CSTR. • Recirculation of the liquid fraction of the digestate provided the necessary buffer in the AD reactors. • A higher OLR (0.9 gVS/L·d) led to higher accumulation of TAN, which caused more toxicity. • A two-stage reactor is more sensitive to elevated concentrations of ammonia. • The IC{sub 50} of TAN for the AD of food waste amounts to 3.8 g/L. - Abstract: This research compares the operation of one-stage and two-stage anaerobic continuously stirred tank reactor (CSTR) systems fed semi-continuously with food waste. The main purpose was to investigate the effects of ammoniacal nitrogen on the anaerobic digestion process. The two-stage system gave more reliable operation compared to one-stage due to: (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; and (iii) a higher conversion rate of organic substrate to biomethane. Also a small amount of biohydrogen was detected from the first stage of the two-stage reactor making this system attractive for biohythane production. As the digestate contains ammoniacal nitrogen, re-circulating it provided the necessary alkalinity in the systems, thus preventing an eventual failure by volatile fatty acids (VFA) accumulation. However, re-circulation also resulted in an ammonium accumulation, yielding a lower biomethane production. Based on the batch experimental results the 50% inhibitory concentration of total ammoniacal nitrogen on the methanogenic activities was calculated as 3.8 g/L, corresponding to 146 mg/L free ammonia for the inoculum used for this research. The two-stage system was affected by the inhibition more than the one-stage system, as it requires less alkalinity and the physically separated methanogens are more sensitive to inhibitory factors, such as ammonium and propionic acid.

Antimicrobial Susceptibility of Enteric Gram Negative Facultative Anaerobe Bacilli in Aerobic versus Anaerobic Conditions

Science.gov (United States)

Amachawadi, Raghavendra G.; Renter, David G.; Volkova, Victoriya V.

2016-01-01

Antimicrobial treatments result in the host’s enteric bacteria being exposed to the antimicrobials. Pharmacodynamic models can describe how this exposure affects the enteric bacteria and their antimicrobial resistance. The models utilize measurements of bacterial antimicrobial susceptibility traditionally obtained in vitro in aerobic conditions. However, in vivo enteric bacteria are exposed to antimicrobials in anaerobic conditions of the lower intestine. Some of enteric bacteria of food animals are potential foodborne pathogens, e.g., Gram-negative bacilli Escherichia coli and Salmonella enterica. These are facultative anaerobes; their physiology and growth rates change in anaerobic conditions. We hypothesized that their antimicrobial susceptibility also changes, and evaluated differences in the susceptibility in aerobic vs. anaerobic conditions of generic E. coli and Salmonella enterica of diverse serovars isolated from cattle feces. Susceptibility of an isolate was evaluated as its minimum inhibitory concentration (MIC) measured by E-Test® following 24 hours of adaptation to the conditions on Mueller-Hinton agar, and on a more complex tryptic soy agar with 5% sheep blood (BAP) media. We considered all major antimicrobial drug classes used in the U.S. to treat cattle: β-lactams (specifically, ampicillin and ceftriaxone E-Test®), aminoglycosides (gentamicin and kanamycin), fluoroquinolones (enrofloxacin), classical macrolides (erythromycin), azalides (azithromycin), sulfanomides (sulfamethoxazole/trimethoprim), and tetracyclines (tetracycline). Statistical analyses were conducted for the isolates (n≥30) interpreted as susceptible to the antimicrobials based on the clinical breakpoint interpretation for human infection. Bacterial susceptibility to every antimicrobial tested was statistically significantly different in anaerobic vs. aerobic conditions on both media, except for no difference in susceptibility to ceftriaxone on BAP agar. A satellite experiment

Proceedings of the 10. world congress on anaerobic digestion 2004 : anaerobic bioconversion, answer for sustainability

International Nuclear Information System (INIS)

2004-01-01

This conference reviewed the broad scope of anaerobic process-related activities taking place globally and confirmed the possibilities of using anaerobic processes to add value to industrial wastewaters, municipal solid wastes and organic wastes while minimizing pollution and greenhouse gases. It focused on biomolecular tools, instrumentation of anaerobic digestion processes, anaerobic bioremediation of chlorinated organics, and thermophilic and mesophilic digestion. Several papers focused on the feasibility of using waste products to produce hydrogen and methane for electricity generation. The sessions of the conference were entitled acidogenesis; microbial ecology; process control; sulfur content; technical development; domestic wastewater; agricultural waste; organic municipal solid wastes; instrumentation; molecular biology; sludges; agricultural feedstock; bioremediation; industrial wastewater; hydrogen production; pretreatments; sustainability; and integrated systems. The conference featured 387 posters and 192 oral presentations, of which 111 have been indexed separately for inclusion in this database. refs., tabs., figs

Kinetics and modeling of anaerobic digestion process

DEFF Research Database (Denmark)

Gavala, Hariklia N.; Angelidaki, Irini; Ahring, Birgitte Kiær

2003-01-01

Anaerobic digestion modeling started in the early 1970s when the need for design and efficient operation of anaerobic systems became evident. At that time not only was the knowledge about the complex process of anaerobic digestion inadequate but also there were computational limitations. Thus...

Isolation of anaerobes from bubo associated with chancroid.

Science.gov (United States)

Kumar, B; Sharma, V K; Bakaya, V; Ayyagiri, A

1991-01-01

Ten men with bubo associated with chancroid were studied for bacterial flora especially anaerobes. Anaerobes were isolated from all 10 buboes and eight out of 10 ulcers of chancroid. Anaerobic cocci, B melaninogenicus and B fragilis were the most common isolates. anaerobes probably play a role in the pathogenesis of bubo in chancroid. PMID:1680792

Comparative evaluation of anoxomat and conventional anaerobic GasPak jar systems for the isolation of anaerobic bacteria.

Science.gov (United States)

Shahin, May; Jamal, Wafaa; Verghese, Tina; Rotimi, V O

2003-01-01

To evaluate the performance of the Anoxomat, in comparison with the conventional anaerobic GasPak jar system, for the isolation of obligate anaerobes. Anoxomat, model WS800, and anaerobic GasPak jar system (Oxoid) were evaluated. Anoxomat system utilized a gas mixture of 80% N(2), 10% CO(2) and 10% H(2), while the GasPak used a gas mixture of 90% H(2) and 10% CO(2). An anaerobic indicator within the jars monitored anaerobiosis. A total of 227 obligate anaerobic bacteria comprising 116 stock strains, 5 ATCC reference strains and 106 fresh strains, representing different genera, were investigated for growth on anaerobic agar plates and scored for density, colony sizes, susceptibility zones of antibiotic inhibition and the speed of anaerobiosis (reducing the indicator). The results demonstrate that the growth of anaerobic bacteria is faster inside the Anoxomat jar than in the anaerobic GasPak jar system. Of the 227 strains tested, the colonies of 152 (67%) were larger (by size range of 0.2-2.4 mm) in the Anoxomat at 48 h than in the GasPak jar compared with only 21% (range 0.1-0.3 mm) that were larger in the GasPak than in the Anoxomat. The remaining 12% were equal in their sizes. There was no measurable difference in the colony sizes of the reference strains. The Porphyromonas asaccharolytica strains failed to grow within the GasPak system but grew inside the Anoxomat. With the Anoxomat, anaerobiosis was achieved about 35 min faster than in the GasPak system. The density of growth recorded for 177 (78%) strains was heavier in the Anoxomat than in the GasPak jar. The zones of inhibition of the antibiotics tested were not different in the two systems. The Anoxomat system provided superior growth, in terms of density and colony size, and achieved anaerobiosis more rapidly. Evidently, the Anoxomat method is more reliable and appears to support the growth of strict anaerobes better. Copyright 2003 S. Karger AG, Basel

Anaerobic bacteraemia revisited: species and susceptibilities.

Science.gov (United States)

Ng, Lily S Y; Kwang, Lee Ling; Rao, Suma; Tan, Thean Yen

2015-01-01

This retrospective study was performed to evaluate the frequency of anaerobic bacteraemia over a 10-year period, and to provide updated antibiotic susceptibilities for the more clinically relevant anaerobes causing blood stream infection. Data were retrieved from the laboratory information system for the period 2003 to 2012. During this time, blood cultures were inoculated in Bactec™ Plus vials (BD, USA) and continuously monitored in the Bactec™ 9000 blood culture system (BD, USA). Anaerobic organisms were identified using commercial identification kits, predominantly API 20 A (bioMérieux, France) supplemented with Vitek ANC cards (bioMérieux, France) and AN-Ident discs (Oxoid, United Kingdom). A representative subset of isolates were retrieved from 2009 to 2011 and antimicrobial susceptibilities to penicillin, amoxicillin-clavulanate, clindamycin, imipenem, moxifloxacin, piperacillin-tazobactam and metronidazole were determined using the Etest method. Anaerobes comprised 4.1% of all positive blood culture with 727 obligate anaerobes recovered over the 10-year period, representing a positivity rate of 0.35%. The only significant change in anaerobe positivity rates occurred between 2003 and 2004, with an increase of 0.2%. The Bacteroides fragilis group (45%) were the predominant anaerobic pathogens, followed by Clostridium species (12%), Propioniobacterium species (11%) and Fusobacterium species (6%). The most active in vitro antibiotics were imipenem, piperacillin-tazobactam, amoxicillin-clavulanate and metronidazole, with susceptibilities of 95.0%, 93.3%, 90.8% and 90.8% respectively. Resistance was high to penicillin, clindamycin and moxifl oxacin. However, there were apparent differences for antibiotic susceptibilities between species. This study indicates that the anaerobes comprise a small but constant proportion of bloodstream isolates. Antibiotic resistance was high to some antibiotics, but metronidazole, the beta-lactam/beta-lactamase inhibitors and

The anaerobic digestion process

Energy Technology Data Exchange (ETDEWEB)

Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

1996-01-01

The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

Anaerobic digestion of cheese whey using up-flow anaerobic sludge blanket reactor

Energy Technology Data Exchange (ETDEWEB)

Yan, J.Q.; Lo, K.V.; Liao, P.H.

1989-01-01

Anaerobic treatment of cheese whey using a 17.5-litre up-flow anaerobic sludge blanket reactor was investigated in the laboratory. The reactor was studied over a range of influent concentration from 4.5 to 38.1 g chemical oxygen demand per litre at a constant hydraulic retention time of 5 days. The reactor start-up and the sludge acclimatization were discussed. The reactor performance in terms of methane production, volatile fatty acids conversion, sludge net growth and chemical oxygen demand reduction were also presented in this paper. Over 97% chemical oxygen demand reduction was achieved in this experiment. At the influent concentration of 38.1 g chemical oxygen demand per litre, an instability of the reactor was observed. The results indicated that the up-flow anaerobic sludge blanket reactor process could treat cheese whey effectively.

Feasibility of thermophilic anaerobic processes for treating waste activated sludge under low HRT and intermittent mixing.

Science.gov (United States)

Leite, Wanderli; Magnus, Bruna Scandolara; Guimarães, Lorena Bittencourt; Gottardo, Marco; Belli Filho, Paulo

2017-10-01

Thermophilic anaerobic digestion (AD) arises as an optimized solution for the waste activated sludge (WAS) management. However, there are few feasibility studies using low solids content typically found in the WAS, and that consider uncommon operational conditions such as intermittent mixing and low hydraulic retention time (HRT). In this investigation, a single-stage pilot reactor was used to treat WAS at low HRT (13, 9, 6 and 5 days) and intermittent mixing (withholding mixing 2 h prior feeding). Thermophilic anaerobic digestion (55 °C) was initiated from a mesophilic digester (35 °C) by the one-step startup strategy. Although instabilities on partial alkalinity (1245-3000 mgCaCO 3 /L), volatile fatty acids (1774-6421 mg/L acetic acid) and biogas production (0.21-0.09 m 3 /m 3 reactor .d) were observed, methanogenesis started to recover in 18 days. The thermophilic treatment of WAS at 13 and 9 days HRT efficiently converted VS into biogas (22 and 21%, respectively) and achieved high biogas yield (0.24 and 0.22 m 3 /kgVS fed , respectively). Intermittent mixing improved the retention of methanogens inside the reactor and reduced the washout effect even at low HRT (5% TS). Copyright © 2017 Elsevier Ltd. All rights reserved.

Diversity Profile of Microbes Associated with Anaerobic Sulfur Oxidation in an Upflow Anaerobic Sludge Blanket Reactor Treating Municipal Sewage

Science.gov (United States)

Aida, Azrina A.; Kuroda, Kyohei; Yamamoto, Masamitsu; Nakamura, Akinobu; Hatamoto, Masashi; Yamaguchi, Takashi

2015-01-01

We herein analyzed the diversity of microbes involved in anaerobic sulfur oxidation in an upflow anaerobic sludge blanket (UASB) reactor used for treating municipal sewage under low-temperature conditions. Anaerobic sulfur oxidation occurred in the absence of oxygen, with nitrite and nitrate as electron acceptors; however, reactor performance parameters demonstrated that anaerobic conditions were maintained. In order to gain insights into the underlying basis of anaerobic sulfur oxidation, the microbial diversity that exists in the UASB sludge was analyzed comprehensively to determine their identities and contribution to sulfur oxidation. Sludge samples were collected from the UASB reactor over a period of 2 years and used for bacterial 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing analyses. T-RFLP and sequencing results both showed that microbial community patterns changed markedly from day 537 onwards. Bacteria belonging to the genus Desulforhabdus within the phylum Proteobacteria and uncultured bacteria within the phylum Fusobacteria were the main groups observed during the period of anaerobic sulfur oxidation. Their abundance correlated with temperature, suggesting that these bacterial groups played roles in anaerobic sulfur oxidation in UASB reactors. PMID:25817585

How deep-sea wood falls sustain chemosynthetic life.

Directory of Open Access Journals (Sweden)

Christina Bienhold

Full Text Available Large organic food falls to the deep sea--such as whale carcasses and wood logs--are known to serve as stepping stones for the dispersal of highly adapted chemosynthetic organisms inhabiting hot vents and cold seeps. Here we investigated the biogeochemical and microbiological processes leading to the development of sulfidic niches by deploying wood colonization experiments at a depth of 1690 m in the Eastern Mediterranean for one year. Wood-boring bivalves of the genus Xylophaga played a key role in the degradation of the wood logs, facilitating the development of anoxic zones and anaerobic microbial processes such as sulfate reduction. Fauna and bacteria associated with the wood included types reported from other deep-sea habitats including chemosynthetic ecosystems, confirming the potential role of large organic food falls as biodiversity hot spots and stepping stones for vent and seep communities. Specific bacterial communities developed on and around the wood falls within one year and were distinct from freshly submerged wood and background sediments. These included sulfate-reducing and cellulolytic bacterial taxa, which are likely to play an important role in the utilization of wood by chemosynthetic life and other deep-sea animals.

How Deep-Sea Wood Falls Sustain Chemosynthetic Life

Science.gov (United States)

Bienhold, Christina; Pop Ristova, Petra; Wenzhöfer, Frank; Dittmar, Thorsten; Boetius, Antje

2013-01-01

Large organic food falls to the deep sea – such as whale carcasses and wood logs – are known to serve as stepping stones for the dispersal of highly adapted chemosynthetic organisms inhabiting hot vents and cold seeps. Here we investigated the biogeochemical and microbiological processes leading to the development of sulfidic niches by deploying wood colonization experiments at a depth of 1690 m in the Eastern Mediterranean for one year. Wood-boring bivalves of the genus Xylophaga played a key role in the degradation of the wood logs, facilitating the development of anoxic zones and anaerobic microbial processes such as sulfate reduction. Fauna and bacteria associated with the wood included types reported from other deep-sea habitats including chemosynthetic ecosystems, confirming the potential role of large organic food falls as biodiversity hot spots and stepping stones for vent and seep communities. Specific bacterial communities developed on and around the wood falls within one year and were distinct from freshly submerged wood and background sediments. These included sulfate-reducing and cellulolytic bacterial taxa, which are likely to play an important role in the utilization of wood by chemosynthetic life and other deep-sea animals. PMID:23301092

New perspectives in anaerobic digestion.

NARCIS (Netherlands)

Lier, van J.B.; Tilche, A.; Ahring, B.K.; Macarie, H.; Moletta, R.; Dohanyos, M.; Hulshoff Pol, L.W.; Lens, P.N.L.; Verstraete, W.

2001-01-01

The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern

Quantifying Contribution of Synthrophic Acetate Oxidation to Methane Production in Thermophilic Anaerobic Reactors by Membrane Inlet Mass Spectrometry

DEFF Research Database (Denmark)

Mulat, Daniel Girma; Ward, Alastair James; Adamsen, Anders Peter S.

2014-01-01

A unique method was developed and applied for monitoring methanogenesis pathways based on isotope labeled substrates combined with online membrane inlet quadrupole mass spectrometry (MIMS). In our study, a fermentation sample from a full-scale biogas plant fed with pig and cattle manure, maize...... silage, and deep litter was incubated with 100 mM of [2-13C] sodium acetate under thermophilic anaerobic conditions. MIMS was used to measure the isotopic distribution of dissolved CO2 and CH4 during the degradation of acetate, while excluding interference from water by applying a cold trap. After 6 days...... a new approach for online quantification of the relative contribution of methanogenesis pathways to methane production with a time resolution shorter than one minute. The observed contribution of SAO-HM to methane production under the tested conditions challenges the current widely accepted anaerobic...

Net alkalinity and net acidity 2: Practical considerations

Science.gov (United States)

Kirby, C.S.; Cravotta, C.A.

2005-01-01

The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH mine drainage treatment can lead to systems with insufficient Alkalinity to neutralize metal and H+ acidity and is not recommended. The use of net alkalinity = -Hot Acidity titration is recommended for the planning of mine drainage treatment. The use of net alkalinity = (Alkalinitymeasured - Aciditycalculated) is recommended with some cautions

Viral abundance and activity in the deep sub-seafloor biosphere

DEFF Research Database (Denmark)

Middelboe, Mathias; Glud, Ronnie N.; Filippini, Manuela

2011-01-01

of undiluted, but homogenized, sediment samples (13.3 and 79.8 mbsf) in anaerobic bags. Viral abundance decreased rapidly (decay rates of 0.010 +/- 0.002 [SD] and 0.022 +/- 0.018 [SD] h(-1), respectively) in the incubations, suggesting that homogenization exposed the viruses to degradation processes. We...... hypothesize that most of the deep subsurface viral communities inhabit a microenvironment where the viruses are protected against decay, and can therefore persist in undisturbed sediments for hundreds of thousands, perhaps even millions, of years....

Hydrogenase-3 contributes to anaerobic acid resistance of Escherichia coli.

Directory of Open Access Journals (Sweden)

Ken Noguchi

Full Text Available BACKGROUND: Hydrogen production by fermenting bacteria such as Escherichia coli offers a potential source of hydrogen biofuel. Because H(2 production involves consumption of 2H(+, hydrogenase expression is likely to involve pH response and regulation. Hydrogenase consumption of protons in E. coli has been implicated in acid resistance, the ability to survive exposure to acid levels (pH 2-2.5 that are three pH units lower than the pH limit of growth (pH 5-6. Enhanced survival in acid enables a larger infective inoculum to pass through the stomach and colonize the intestine. Most acid resistance mechanisms have been defined using aerobic cultures, but the use of anaerobic cultures will reveal novel acid resistance mechanisms. METHODS AND PRINCIPAL FINDINGS: We analyzed the pH regulation of bacterial hydrogenases in live cultures of E. coli K-12 W3110. During anaerobic growth in the range of pH 5 to 6.5, E. coli expresses three hydrogenase isoenzymes that reversibly oxidize H(2 to 2H(+. Anoxic conditions were used to determine which of the hydrogenase complexes contribute to acid resistance, measured as the survival of cultures grown at pH 5.5 without aeration and exposed for 2 hours at pH 2 or at pH 2.5. Survival of all strains in extreme acid was significantly lower in low oxygen than for aerated cultures. Deletion of hyc (Hyd-3 decreased anoxic acid survival 3-fold at pH 2.5, and 20-fold at pH 2, but had no effect on acid survival with aeration. Deletion of hyb (Hyd-2 did not significantly affect acid survival. The pH-dependence of H(2 production and consumption was tested using a H(2-specific Clark-type electrode. Hyd-3-dependent H(2 production was increased 70-fold from pH 6.5 to 5.5, whereas Hyd-2-dependent H(2 consumption was maximal at alkaline pH. H(2 production, was unaffected by a shift in external or internal pH. H(2 production was associated with hycE expression levels as a function of external pH. CONCLUSIONS: Anaerobic growing

Modified anaerobic digestion elutriated phased treatment for the anaerobic co-digestion of sewage sludge and food wastewater.

Science.gov (United States)

Mo, Kyung; Lee, Wonbae; Kim, Moonil

2017-02-01

A modified anaerobic digestion elutriated phased treatment (MADEPT) process was developed for investigating anaerobic co-digestion of sewage sludge and food wastewater. The anaerobic digestion elutriated phased treatment (ADEPT) process is similar to a two-phase system, however, in which the effluent from a methanogenic reactor recycles into an acidogenic reactor to elutriate mainly dissolved organics. Although ADEPT could reduce reactor volume significantly, the unsolubilized solids should be wasted from the system. The MADEPT process combines thermo-alkali solubilization with ADEPT to improve anaerobic performance and to minimize the sludge disposal. It was determined that the optimal volume mixing ratio of sewage sludge and food wastewater was 4 : 1 for the anaerobic co-digestion. The removal efficiencies of total chemical oxygen demand, volatile solids, and volatile suspended solids in the MADEPT process were 73%, 70%, and 64%, respectively. However, those in the ADEPT process were only 48%, 37%, and 40%, respectively, at the same hydraulic retention time (HRT) of 7 days. The gas production of MADEPT was two times higher than that of ADEPT. The thermo-alkali solubilization increased the concentration of dissolved organics so that they could be effectively degraded in a short HRT, implying that MADEPT could improve the performance of ADEPT in anaerobic co-digestion.

Anaerobic digestion of piggery waste

NARCIS (Netherlands)

Velsen, van A.F.M.

1981-01-01

Anaerobic digestion is a biological process by which organic matter is converted to methane and carbon dioxide by microbes in the absence of air (oxygen). In nature, anaerobic conversions occur at all places where organic material accumulates and the supply of oxygen is deficient, e.g. in marshes

Investigation of Sulfate concentration influence on Anaerobic Lagoon performance: Birjand Wastewater Treatment plant: A Case study

Directory of Open Access Journals (Sweden)

Mohammad Malakootian

2016-05-01

Full Text Available Background and Aim: In the present study the influence of the different sulfate concentration on the anaerobic lagoon stabilization was investigated. Materials and Methods: The present study is an experimental research carried out on anaerobic stabilization pond pilot for 7 months in Birjand wastewater treatment plant. After making sure of a steady state sulfate with different concentrations of 200, 300 and 400 mg/L were injected into the pilot. Then parameters including pH, organic nitrogen, ammonia nitrogen, BOD5, COD and nitrate were measured. All of the experiments were carried out according to the methods presented in the book "Standard Method" for the examination of water and wastewater (2005. Results: It was found that by increasing sulfate concentration from 200 to 300 mg/L all of parameters  except BOD5 (10% reduction had no significant changes., but by increasing the sulfate concentration from 200 to 400 mg/L the removal efficiency of the parameters such as BOD5, COD, Organic nitrogen, total kjeldahl nitrogen, nitrate and sulfate reduced to 11, 8, 12, 26, 6 and 10 percent, respectively. PH in the first stage was alkaline and then changed to acidic. Conclusion: Anaerobic stabilization ponds have different capacities for removal of organic compounds at different sulfate concentrations; so that; in sulfate concentration of 200 mg/L, the proper operation was seen and in concentration of 300 mg/L, sulfate-reducing bacteria get dominant and therefore odor is produced..  Alternatively, by increasing the concentration of sulphate to 400 mg/L, ammonia nitrogen increased 2.5 times (150% in the effluent.

Processing Methods of Alkaline Hydrolysate from Rice Husk

Directory of Open Access Journals (Sweden)

Olga D. Arefieva

2017-07-01

Full Text Available This paper devoted to finding processing methods of alkaline hydrolysate produced from rice husk pre-extraction, and discusses alkaline hydrolysate processing schemed and disengagement of some products: amorphous silica of various quality, alkaline lignin, and water and alkaline extraction polysaccharides. Silica samples were characterized: crude (air-dried, burnt (no preliminary water treatment, washed in distilled water, and washed in distilled water and burnt. Waste water parameters upon the extraction of solids from alkaline hydrolysate dropped a few dozens or thousand times depending on the applied processing method. Color decreased a few thousand times, turbidity was virtually eliminated, chemical oxygen demanded about 20–136 times; polyphenols content might decrease 50% or be virtually eliminated. The most prospective scheme obtained the two following solid products from rice husk alkaline hydrolysate: amorphous silica and alkaline extraction polysaccharide. Chemical oxygen demand of the remaining waste water decreased about 140 times compared to the silica-free solution.

A model for Nb-Zr-REE-Ga enrichment in Lopingian altered alkaline volcanic ashes: Key evidence of H-O isotopes

Science.gov (United States)

Dai, Shifeng; Nechaev, Victor P.; Chekryzhov, Igor Yu.; Zhao, Lixin; Vysotskiy, Sergei V.; Graham, Ian; Ward, Colin R.; Ignatiev, Alexander V.; Velivetskaya, Tatyana A.; Zhao, Lei; French, David; Hower, James C.

2018-03-01

Clay-altered volcanic ash with highly-elevated concentrations of Nb(Ta), Zr(Hf), rare earth elements (REE), and Ga, is a new type of critical metal deposit with high commercial prospects that has been discovered in Yunnan Province, southwest China. Previous studies showed that the volcanic ashes had been subjected to hydrothermal fluids, the nature of which, however, is not clear. Here we show that the volcanic ashes were originated from alkaline magmatism, followed by a continuous hydrothermal-weathering process. Heated meteoric waters, which were sourced from acidic rains and mixed with CO2 from degassing of the Emeishan plume, have caused partial, but widespread, acidic leaching of Nb, Ta, Zr, Hf, REE, and Ga into ground water and residual enrichment of these elements, along with Al and Ti, in the deeply altered rocks. Subsequent alteration occurring under cooler, neutral or alkaline conditions, caused by water-rock interaction, resulted in precipitation of the leached critical metals in the deposit. Polymetallic mineralization of similar origin may be found in other continental regions subjected to explosive alkaline volcanism associated with deep weathering in humid conditions.

[Distribution and removal of anaerobic antibiotic resistant bacteria during mesophilic anaerobic digestion of sewage sludge].

Science.gov (United States)

Tong, Juan; Wang, Yuan-Yue; Wei Yuan, Song

2014-10-01

Sewage sludge is one of the major sources that releasing antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) into the environment since it contains large amount of ARB, but there is little information about the fate of the anaerobic ARB in the anaerobic digestion of sewage sludge. Therefore, the distribution, removal and seasonal changes of tetracycline and β-lactam antibiotics resistant bacteria in the mesophilic egg-shaped digesters of a municipal wastewater treatment plant were investigated for one year in this study. Results showed that there were higher amounts of ARB and higher resistance rate of β-lactam antibiotics than that of tetracycline antibiotics in the sewage sludge. All ARB could be significantly reduced during the mesophilic anaerobic digestion process by 1.48-1.64 log unit (P anaerobic digestion by 12.0% and 14.3%, respectively (P bacteria, there were more ARB in the sewage sludge in cold season than in warm season (P < 0.05).

In vitro activity of mecillinam against anaerobic bacteria.

OpenAIRE

Steinkraus, G E; McCarthy, L R

1980-01-01

A microtiter broth dilution method was employed to determine the in vitro activity of mecillinam against 201 recent clinical isolates of anaerobic bacteria. Both the anerobic gram-positive and anaerobic gram-negative bacilli displayed a wide range of minimal inhibitory concentrations of mecillinam; most strains were resistant to the antibiotic. The anaerobic cocci exhibited a narrower range of minimal inhibitory concentrations than were observed with other anaerobes, but also exhibited mecill...

Advanced alkaline water electrolysis

International Nuclear Information System (INIS)

Marini, Stefania; Salvi, Paolo; Nelli, Paolo; Pesenti, Rachele; Villa, Marco; Berrettoni, Mario; Zangari, Giovanni; Kiros, Yohannes

2012-01-01

A short review on the fundamental and technological issues relevant to water electrolysis in alkaline and proton exchange membrane (PEM) devices is given. Due to price and limited availability of the platinum group metal (PGM) catalysts they currently employ, PEM electrolyzers have scant possibilities of being employed in large-scale hydrogen production. The importance and recent advancements in the development of catalysts without PGMs are poised to benefit more the field of alkaline electrolysis rather than that of PEM devices. This paper presents our original data which demonstrate that an advanced alkaline electrolyzer with performances rivaling those of PEM electrolyzers can be made without PGM and with catalysts of high stability and durability. Studies on the advantages/limitations of electrolyzers with different architectures do show how a judicious application of pressure differentials in a recirculating electrolyte scheme helps reduce mass transport limitations, increasing efficiency and power density.

The Evolution of Deep Ocean Chemistry and Respired Carbon in the Eastern Equatorial Pacific Over the Last Deglaciation

Science.gov (United States)

de la Fuente, Maria; Calvo, Eva; Skinner, Luke; Pelejero, Carles; Evans, David; Müller, Wolfgang; Povea, Patricia; Cacho, Isabel

2017-12-01

It has been shown that the deep Eastern Equatorial Pacific (EEP) region was poorly ventilated during the Last Glacial Maximum (LGM) relative to Holocene values. This finding suggests a more efficient biological pump, which indirectly supports the idea of increased carbon storage in the deep ocean contributing to lower atmospheric CO2 during the last glacial. However, proxies related to respired carbon are needed in order to directly test this proposition. Here we present Cibicides wuellerstorfi B/Ca ratios from Ocean Drilling Program Site 1240 measured by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) as a proxy for deep water carbonate saturation state (Δ[CO32-], and therefore [CO32-]), along with δ13C measurements. In addition, the U/Ca ratio in foraminiferal coatings has been analyzed as an indicator of oxygenation changes. Our results show lower [CO32-], δ13C, and [O2] values during the LGM, which would be consistent with higher respired carbon levels in the deep EEP driven, at least in part, by reduced deep water ventilation. However, the difference between LGM and Holocene [CO32-] observed at our site is relatively small, in accordance with other records from across the Pacific, suggesting that a "counteracting" mechanism, such as seafloor carbonate dissolution, also played a role. If so, this mechanism would have increased average ocean alkalinity, allowing even more atmospheric CO2 to be "sequestered" by the ocean. Therefore, the deep Pacific Ocean very likely stored a significant amount of atmospheric CO2 during the LGM, specifically due to a more efficient biological carbon pump and also an increase in average ocean alkalinity.

Potential for anaerobic conversion of xenobiotics

DEFF Research Database (Denmark)

Mogensen, Anders Skibsted; Dolfing, J.; Haagensen, Frank

2003-01-01

This review covers the latest research on the anaerobic biodegradation of aromatic xenobiotic compounds, with emphasis on surfactants, polycyclic aromatic hydrocarbons, phthalate esters, polychlorinated biphenyls, halogenated phenols, and pesticides. The versatility of anaerobic reactor systems...... regarding the treatment of xenobiotics is shown with the focus on the UASB reactor, but the applicability of other reactor designs for treatment of hazardous waste is also included. Bioaugmentation has proved to be a viable technique to enhance a specific activity in anaerobic reactors and recent research...

Qualitative Carbohydrate Analysis using Alkaline Potassium ...

Indian Academy of Sciences (India)

IAS Admin

CLASSROOM. 285. RESONANCE | March 2016. Qualitative Carbohydrate Analysis using Alkaline. Potassium Ferricyanide. Keywords. Alkaline potassium ferricyanide, qualitative ... Carbohydrates form a distinct class of organic compounds often .... Laboratory Techniques: A contemporary Approach, W B Saunders Com-.

Prospects of Anaerobic Digestion Technology in China

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

As the world's largest developing country, China must face the problem of managing municipal solid waste, and the challenge of organic waste disposal is even more serious. Considering the characteristics of traditional waste disposal technologies and the subsequent secondary pollution, anaerobic digestion has various advantages such as reduction in the land needed for disposal and preservation of environmental quality. In light of the energy crisis, this paper focuses on the potential production of biogas from biowaste through anaerobic digestion processes, the problems incurred by the waste collection system, and the efficiency of the anaerobic digestion process. Use of biogas in a combined heat and power cogeneration system is also discussed. Finally, the advantages of anaerobic digestion technology for the Chinese market are summarized. The anaerobic digestion is suggested to be a promising treating technology for the organic wastes in China.

Anaerobic Digestion Foaming Causes

OpenAIRE

Ganidi, Nafsika

2008-01-01

Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...

Distribution of tetracycline resistance genes in anaerobic treatment of waste sludge: The role of pH in regulating tetracycline resistant bacteria and horizontal gene transfer.

Science.gov (United States)

Huang, Haining; Chen, Yinguang; Zheng, Xiong; Su, Yinglong; Wan, Rui; Yang, Shouye

2016-10-01

Although pH value has been widely regarded as an important factor that affects resource recovery of waste sludge, the potential influence of diverse pHs on the distribution of tetracycline resistance genes (TRGs) during sludge anaerobic treatment is largely unknown. Here we reported that in the range of pH 4-10, 0.58-1.18 log unit increase of target TRGs was observed at pH 4, compared with that at pH 7, while 0.70-1.31 log unit further removal were obtained at pH 10. Mechanism study revealed that varied pHs not only altered the community structures of tetracycline resistant bacteria (TRB), but also changed their relative abundances, benefitting the propagation (acidic pHs) or attenuation (alkaline pHs) of TRB. Further investigation indicated that the amount and gene-possessing abilities of key genetic vectors for horizontal TRGs transfer were greatly promoted at acidic pHs but restricted under alkaline conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antimicrobial resistance and susceptibility testing of anaerobic bacteria.

Science.gov (United States)

Schuetz, Audrey N

2014-09-01

Infections due to anaerobic bacteria can be severe and life-threatening. Susceptibility testing of anaerobes is not frequently performed in laboratories, but such testing is important to direct appropriate therapy. Anaerobic resistance is increasing globally, and resistance trends vary by geographic region. An overview of a variety of susceptibility testing methods for anaerobes is provided, and the advantages and disadvantages of each method are reviewed. Specific clinical situations warranting anaerobic susceptibility testing are discussed. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

EFFECT OF MUSIC ON ANAEROBIC EXERCISE PERFORMANCE

Directory of Open Access Journals (Sweden)

Tülin Atan

2013-01-01

Full Text Available For years, mostly the effects of music on cardiorespiratory exercise performance have been studied, but a few studies have examined the effect of music on anaerobic exercise. The purpose of this study was to assess the effect of listening to music and its rhythm on anaerobic exercise: on power output, heart rate and the concentration of blood lactate. 28 male subjects were required to visit the laboratory on 6 occasions, each separated by 48 hours. Firstly, each subject performed the Running-based Anaerobic Sprint Test (RAST under 3 conditions on separate days: while listening to “slow rhythm music”, “fast rhythm music” or “no music”. 48 hours after the subjects completed RAST under 3 conditions, Wingate Anaerobic Power (WAN tests were performed under 3 music conditions. The order of the 3 conditions (slow music, fast music and no music was selected randomly to prevent an order effect. Results showed no significant differences between 3 conditions in anaerobic power assessments, heart rate or blood lactate (p>0.05. On the basis of these results it can be said that music cannot improve anaerobic performance. The type of music had no impact on power outputs during RAST and WAN exercise. As a conclusion, listening to music and its rhythm cannot enhance anaerobic performance and cannot change the physiological response to supramaximal exercise.

Identification of anaerobic arsenite-oxidizing and arsenate-reducing bacteria associated with an alkaline saline lake in Khovsgol, Mongolia.

Science.gov (United States)

Hamamura, Natsuko; Itai, Takaaki; Liu, Yitai; Reysenbach, Anna-Louise; Damdinsuren, Narantuya; Inskeep, William P

2014-10-01

Microbial arsenic transformation pathways associated with a saline lake located in northern Mongolia were examined using molecular biological and culturing approaches. Bacterial 16S rRNA gene sequences recovered from saline lake sediments and soils were affiliated with haloalkaliphiles, including Bacillus and Halomonas spp. Diverse sequences of arsenate respiratory reductase (arrA) and a new group of arsenite oxidase (arxA) genes were also identified. Pure cultures of arsenate-reducing Nitrincola strain and anaerobic arsenite-oxidizing Halomonas strain were isolated. The chemoorganotrophic Halomonas strain contains arxA gene similar to that of a chemoautotrophic arsenite-oxidizing Alkalilimnicola ehrlichii strain MLHE-1. These results revealed the diversity of arsenic transformation pathways associated with a geographically distinct saline system and the potential contribution of arx-dependent arsenite oxidation by heterotrophic bacteria.

Odor from anaerobic digestion of swine slurry: influence of pH, temperature and organic loading

Directory of Open Access Journals (Sweden)

Gerardo Ortiz

2014-12-01

Full Text Available Farm slurry management from storage and/or treatment is the main source of odors from swine production, which are determined by factors such as operational variations (organic loading, cleaning of facilities and animal diet (pH or environmental conditions (temperature. The aim of this study was to evaluate the influence of pH, temperature and organic loading on odor generation during anaerobic digestion of swine slurry. The methodology employed batch experimental units under controlled pH (6.0, 6.5, 7.0 and 8.0 and temperature (20, 35 and 55 °C conditions. Additionally, an Upflow Anaerobic Sludge Blanket (UASB system was operated under two Organic Loading Rate (OLR conditions as Chemical Oxygen Demand (COD (Phase I: 0.4 g L-1 d-1 of COD, Phase II: 1.1 g L-1 d-1 of COD. Odor (batch and UASB reactor was evaluated by detection and recognition threshold as Dilution Threshold (D-T. Acidic conditions (pH 6.0 and thermophilic temperatures (55 °C increased odors (1,358 D-T and acidified the system (Intermediate/Total Alkalinity ratio (IT/TA: 0.85 in batch experiments. Increasing OLR on UASB reactor reduced odors from 6.3 to 9.6 D-T d-1 due to an increase in the production of biogas (0.4 to 0.6 g g-1 COD removed of biogas.

Comparison of single-stage and temperature-phased two-stage anaerobic digestion of oily food waste

International Nuclear Information System (INIS)

Wu, Li-Jie; Kobayashi, Takuro; Li, Yu-You; Xu, Kai-Qin

2015-01-01

Highlights: • A single-stage and two two-stage anaerobic systems were synchronously operated. • Similar methane production 0.44 L/g VS_a_d_d_e_d from oily food waste was achieved. • The first stage of the two-stage process became inefficient due to serious pH drop. • Recycle favored the hythan production in the two-stage digestion. • The conversion of unsaturated fatty acids was enhanced by recycle introduction. - Abstract: Anaerobic digestion is an effective technology to recover energy from oily food waste. A single-stage system and temperature-phased two-stage systems with and without recycle for anaerobic digestion of oily food waste were constructed to compare the operation performances. The synchronous operation indicated the similar ability to produce methane in the three systems, with a methane yield of 0.44 L/g VS_a_d_d_e_d. The pH drop to less than 4.0 in the first stage of two-stage system without recycle resulted in poor hydrolysis, and methane or hydrogen was not produced in this stage. Alkalinity supplement from the second stage of two-stage system with recycle improved pH in the first stage to 5.4. Consequently, 35.3% of the particulate COD in the influent was reduced in the first stage of two-stage system with recycle according to a COD mass balance, and hydrogen was produced with a percentage of 31.7%, accordingly. Similar solids and organic matter were removed in the single-stage system and two-stage system without recycle. More lipid degradation and the conversion of long-chain fatty acids were achieved in the single-stage system. Recycling was proved to be effective in promoting the conversion of unsaturated long-chain fatty acids into saturated fatty acids in the two-stage system.

Metabolic interactions between methanogenic consortia and anaerobic respiring bacteria

DEFF Research Database (Denmark)

Stams, A.J.; Oude Elferink, S.J.; Westermann, Peter

2003-01-01

Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic respiring bacteria are toxic to methanogenic...... consortia. Despite the potentially adverse effects, only few inorganic electron acceptors potentially utilizable for anaerobic respiration have been investigated with respect to negative interactions in anaerobic digesters. In this chapter we review competitive and inhibitory interactions between anaerobic...... respiring populations and methanogenic consortia in bioreactors. Due to the few studies in anaerobic digesters, many of our discussions are based upon studies of defined cultures or natural ecosystems...

Cyclic, Early Diagenetic Dolomite Formation in Alkaline Lake Van

Science.gov (United States)

McCormack, J.; Bontognali, T. R. R.; Immenhauser, A.; Kwiecien, O.

2017-12-01

Modern dolomite-forming environments are commonly constrained to evaporitic marine or marginal marine settings such as lagoons and sabkhas. Beside microbial mediation, high temperatures and Mg2+ concentrations in solution are factors considered important in aiding dolomite formation. Accordingly, previous studies associate the presence of dolomite within deep sediments of alkaline Lake Van (Turkey) with periods of enhanced evaporation, low lake levels and high Mg/Ca ratio. We systematically studied dolomite within the sedimentary record of Lake Van by means of XRD, SEM and stable isotope (δ18O and δ13C) mass spectrometry. First, we considered the origin of the dolomite; next, we focused on the wider implication of its presence. SEM imaging documents large dolomite crystals interwoven with clay minerals and individual crystals with different crystallographic orientations grown together, indicating space-limited growth within the sediment. According to recent climatic reconstructions for the same sequence (ICDP PALEOVAN project), the water depth of the coring site - today at 350 m - unlikely fell below 200 m. Consequently, dolomite formed below a thick water column at constantly low temperatures (supported by heavy δ18O signature). Within this environment, variations in Mg/Ca ratio, pH and alkalinity, which are constantly high, have no effect on the episodic nature of dolomite precipitation. These observations call for a re-evaluation of the palaeoenvironments often invoked to interpret intervals rich in dolomite within ancient sedimentary sequences (e.g., periods of enhanced aridity and evaporation). Further, and in contrast to previous interpretations, our dolomite concentration data backed up by ICDP PALEOVAN reconstructions suggest that intervals rich in dolomite coincide with periods of high lake level and increased humidity. High dolomite concentrations (20 - 85 % relative carbonate content) occur cyclically within the last glacial period and coincide with

Increased river alkalinization in the Eastern U.S.

Science.gov (United States)

Kaushal, Sujay S; Likens, Gene E; Utz, Ryan M; Pace, Michael L; Grese, Melissa; Yepsen, Metthea

2013-09-17

The interaction between human activities and watershed geology is accelerating long-term changes in the carbon cycle of rivers. We evaluated changes in bicarbonate alkalinity, a product of chemical weathering, and tested for long-term trends at 97 sites in the eastern United States draining over 260,000 km(2). We observed statistically significant increasing trends in alkalinity at 62 of the 97 sites, while remaining sites exhibited no significant decreasing trends. Over 50% of study sites also had statistically significant increasing trends in concentrations of calcium (another product of chemical weathering) where data were available. River alkalinization rates were significantly related to watershed carbonate lithology, acid deposition, and topography. These three variables explained ~40% of variation in river alkalinization rates. The strongest predictor of river alkalinization rates was carbonate lithology. The most rapid rates of river alkalinization occurred at sites with highest inputs of acid deposition and highest elevation. The rise of alkalinity in many rivers throughout the Eastern U.S. suggests human-accelerated chemical weathering, in addition to previously documented impacts of mining and land use. Increased river alkalinization has major environmental implications including impacts on water hardness and salinization of drinking water, alterations of air-water exchange of CO2, coastal ocean acidification, and the influence of bicarbonate availability on primary production.

Anaerobic degradation of linear alkylbenzene sulfonate

DEFF Research Database (Denmark)

Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær

2003-01-01

Linear alkylbenzene sulfonate (LAS) found in wastewater is removed in the wastewater treatment facilities by sorption and aerobic biodegradation. The anaerobic digestion of sewage sludge has not been shown to contribute to the removal. The concentration of LAS based on dry matter typically...... increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C...

Is anaerobic blood culture necessary? If so, who needs it?

Science.gov (United States)

Iwata, Kentaro; Takahashi, Miwa

2008-07-01

The role of anaerobic blood cultures is not validated, although they are drawn routinely. We performed a retrospective chart review at a private hospital in Japan for patients admitted between July 1, 2004 to June 30, 2005 to determine patient characteristics resulting in anaerobic blood culture. During the study period, 17,775 blood culture bottles were sent for the analysis, and 2132 bottles (12.0%) were positive for microbial growth. Bacteria were grown from 958 anaerobic bottles (44.7%), and 719 (33.7%) of those were judged to represent real infections, which accounted for 410 cases of bacteremia. Only 47 cases (11.5%) were detected by anaerobic cultures alone. Among those 47, obligate anaerobes represented 12 cases. Clinical evaluation could have predicted 7 of 12 cases of obligate anaerobic bacteremia. In the remaining 5 cases, the source of bacteremia was unclear. There were 2.7 cases of anaerobic bacteremia per 1000 blood cultures. The mortality attributable to anaerobic bacteremia was 50%. Among bacteremic cases not caused by obligate anaerobes yet diagnosed solely by anaerobic bottles, either the standard 2 sets of blood were not taken or their clinical outcomes were favorable. Anaerobic blood culture can be avoided in most cases. Anaerobic blood culture may be most helpful when (1) bacteremia because of obligate anaerobes is clinically suspected, (2) patients are severely immunocompromised, and (3) source of bacteremia is not identified by clinical evaluation.

Microbial network for waste activated sludge cascade utilization in an integrated system of microbial electrolysis and anaerobic fermentation

DEFF Research Database (Denmark)

Liu, Wenzong; He, Zhangwei; Yang, Chunxue

2016-01-01

Background: Bioelectrochemical systems have been considered a promising novel technology that shows an enhanced energy recovery, as well as generation of value-added products. A number of recent studies suggested that an enhancement of carbon conversion and biogas production can be achieved....... The characterization of integrated community structure and community shifts is not well understood, however, it starts to attract interest of scientists and engineers. Results: In the present work, energy recovery and WAS conversion are comprehensively affected by typical pretreated biosolid characteristics. We...... investigated the interaction of fermentation communities and electrode respiring communities in an integrated system of WAS fermentation and MEC for hydrogen recovery. A high energy recovery was achieved in the MECs feeding WAS fermentation liquid through alkaline pretreatment. Some anaerobes belonging...

Anaerobic digestion for sustainable development: a natural approach.

Science.gov (United States)

Gljzen, H J

2002-01-01

After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These 'natural reactors' exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic posttreatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery.

Gardnerella vaginalis and anaerobic bacteria in genital disease.

Science.gov (United States)

Tabaqchali, S; Wilks, M; Thin, R N

1983-01-01

In a study of Gardnerella vaginalis and anaerobic bacteria in non-specific vaginitis (NSV) and other genital disease 89 patients attending a genital medicine clinic had vaginal samples examined for conventional pathogens and for quantitative analysis of G vaginalis and aerobic and anaerobic bacterial flora. The overall incidence of G vaginalis was 20%; G vaginalis (mean concentration 7.0 log10/g of secretion) occurred predominantly in patients with NSV (57%) but also in sexual contacts of non-specific urethritis (NSU) (37.5%) and in patients with other conditions (11.8%). G vaginalis is therefore a relatively common isolate in patients with vaginal discharge. The concentration of aerobic and anaerobic bacteria ranged from 4.9-11.0 log10/g of secretion with an anaerobe-to-aerobe ratio of 10:1. Anaerobic bacteria, particularly anaerobic Gram-positive cocci (mean concentrations 7.7 log10/g), were present in patients with NSV and in association with G vaginalis, but they also occurred in other clinical groups and with other pathogens, particularly Trichomonas vaginalis. Anaerobic bacteria may therefore play an important role in the pathogenesis of vaginal infections. PMID:6600955

Posttranslational heterogeneity of bone alkaline phosphatase in metabolic bone disease.

Science.gov (United States)

Langlois, M R; Delanghe, J R; Kaufman, J M; De Buyzere, M L; Van Hoecke, M J; Leroux-Roels, G G

1994-09-01

Bone alkaline phosphatase is a marker of osteoblast activity. In order to study the posttranscriptional modification (glycosylation) of bone alkaline phosphatase in bone disease, we investigated the relationship between mass and catalytic activity of bone alkaline phosphatase in patients with osteoporosis and hyperthyroidism. Serum bone alkaline phosphatase activity was measured after lectin precipitation using the Iso-ALP test kit. Mass concentration of bone alkaline phosphatase was determined with an immunoradiometric assay (Tandem-R Ostase). In general, serum bone alkaline phosphatase mass and activity concentration correlated well. The activity : mass ratio of bone alkaline phosphatase was low in hyperthyroidism. Activation energy of the reaction catalysed by bone alkaline phosphatase was high in osteoporosis and in hyperthyroidism. Experiments with neuraminidase digestion further demonstrated that the thermodynamic heterogeneity of bone alkaline phosphatase can be explained by a different glycosylation of the enzyme.

Validity of the Pediatric Running-Based Anaerobic Sprint Test to Determine Anaerobic Performance in Healthy Children

NARCIS (Netherlands)

Bongers, Bart C.; Werkman, Maarten S.; Blokland, Donna; Eijsermans, Maria J. C.; van der Torre, Patrick; Bartels, Bart; Verschuren, Olaf; Takken, Tim

Purpose: To determine criterion validity of the pediatric running-based anaerobic sprint test (RAST) as a nonsophisticated field test for evaluating anaerobic performance in healthy children and adolescents. Methods: Data from 65. healthy children (28 boys and 37 girls between 6 and 18 years of age,

Improved electrodes and gas impurity investigations on alkaline electrolysers

DEFF Research Database (Denmark)

Reissner, R.; Schiller, G.; Knoeri, T.

Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved.......Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved....

Anaerobic Digestion. Student Manual. Biological Treatment Process Control.

Science.gov (United States)

Carnegie, John W., Ed.

This student manual contains the textual material for a four-lesson unit on anaerobic digestion control. Areas addressed include: (1) anaerobic sludge digestion (considering the nature of raw sludge, purposes of anaerobic digestion, the results of digestion, types of equipment, and other topics); (2) digester process control (considering feeding…

Are high rates of sulphate reduction associated with anaerobic oxidation of methane

Energy Technology Data Exchange (ETDEWEB)

Devol, A H; Ahmed, S I

1981-01-01

Classical models of sulphur diagenesis in marine sediments are based on the assumption that the rate of sulphate reduction is first order with respect to oxidizable particulate organic carbon (POC). This assumption requires that oxidizable POC, sulphate concentration and the sulphate reduction rate be highest at the top of the sulphate reduction zone and decrease exponentially with increasing sediment depth. However, to explain recent observations of concave upwards methane distributions, the anaerobic consumption of methane has been proposed. Furthermore, it has been proposed that this consumption takes place near the bottom of the sulphate reducing zone where sulphate concentrations are low. Thus, if sulphate reducing bacteria are associated with the anaerobic oxidation of methane, a peak in sulphate reduction rate might be expected in this deep consumption zone. The importance of the process in sedimentary sulphur diagenesis is indicated by calculations estimating that 30 to 75% of the downward sulphate flux at depth may be consumed by methane oxidation within this zone. We present here profiles of sulphate reduction rate in anoxic sediments that show distinct local maxima at the depth where the anaerobic oxidation of methane would be expected. Our measurements were made during July and August 1978 in Saanich Inlet, an anoxic fjord located on the south-east of Vancouver Island, British Columbia. The inlet has a shallow sill (approx 70 m) which restricts circulation of the deeper water (maximum depth 225 m) inside the basin to the extent that for about 8 months of the year the bottom waters contain hydrogen sulphide, the inlet is an ideal location for studying sedimentary sulphate reduction because reactions with oxygen and the effects of burrowing organisms can be neglected.

Anaerobic digestion for sustainable development: a natural approach

Energy Technology Data Exchange (ETDEWEB)

Gijzen, H.J.

2002-07-01

After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These ''natural reactors'' exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic post-treatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. In conclusion: a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery. (author)

Effect of saponification on the anaerobic digestion of solid fatty residues.

Science.gov (United States)

Mouneimne, A H; Carrère, H; Bernet, N; Delgenès, J P

2003-10-01

In France, fatty residues considered as "non-ultimate" waste will not be accepted in landfill from 2002, in accordance with French legislation. Anaerobic digestion appears as an alternative process to mobilize and profitably use such fermentable waste. In this work, the effect of an alkaline pretreatment on the degradation of hexane extractible matter (HEM) and the production of volatile fatty acids (VFAs) was compared in reactors working at pH 6.5 and 8.5. The results obtained showed that 40% (+/- 0.1) of HEM were degraded at pH 8.5 versus 10% (+/- 0.3) at pH 6.5, regardless of the alkali agent used to saponify the greasy wastes. The highest performances of VFA production (8.45% +/- 0.3) were obtained at pH 8.5 with greases saponified by potassium hydroxide, compared to results (4.25% +/- 0.1) with greasy waste saponified by sodium hydroxide. This difference in VFA production might be attributable to biotoxic molecules generated during the saponification of greases by soda, limiting consequently the VFA production process.

Analysis of Low-Biomass Microbial Communities in the Deep Biosphere.

Science.gov (United States)

Morono, Y; Inagaki, F

2016-01-01

Over the past few decades, the subseafloor biosphere has been explored by scientific ocean drilling to depths of about 2.5km below the seafloor. Although organic-rich anaerobic sedimentary habitats in the ocean margins harbor large numbers of microbial cells, microbial populations in ultraoligotrophic aerobic sedimentary habitats in the open ocean gyres are several orders of magnitude less abundant. Despite advances in cultivation-independent molecular ecological techniques, exploring the low-biomass environment remains technologically challenging, especially in the deep subseafloor biosphere. Reviewing the historical background of deep-biosphere analytical methods, the importance of obtaining clean samples and tracing contamination, as well as methods for detecting microbial life, technological aspects of molecular microbiology, and detecting subseafloor metabolic activity will be discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Susceptibility of anaerobic bacteria in Auckland: 1991-1996.

Science.gov (United States)

Shore, K P; Pottumarthy, S; Morris, A J

1999-11-12

To determine the antimicrobial susceptibility of local anaerobic bacteria. The antimicrobial susceptibility of 357 obligate anaerobes collected between 1991 and 1997 was determined by a standard agar dilution method. Isolates tested included Bacteroides spp. 131, Fusobacterium spp. 12, Prevotella spp. 13, Veillonella spp. 5, Clostridium perfringens 27, other Clostridium spp. 29, Propionibacterium spp. 57, Actinomyces spp. 7, other non-sporing gram-positive bacilli 28 and Peptostreptococcus spp. 48. Ten antimicrobials were tested: penicillin, amoxycillin/ clavulanic acid, pipercillin/tazobactam, ceftriaxone, cefoxitin, cefotetan, imipenem, meropenem, clindamycin and metronidazole. Imipenem, pipercillin/tazobactam, meropenem and amoxycillin/clavulanic acid were active against virtually all anaerobes tested. Metronidazole was active against all anaerobic gram-negative bacteria and Clostridium spp., but had variable activity against other anaerobes. Cefoxitin was the most active cephalosporin against Bacteroides spp., with 76%, 64% and 15% of Bacteroides spp. being susceptible to cefoxitin, cefotetan and ceftriaxone, respectively. Penicillin had poor activity against anaerobic gram negative bacilli. Actinomyces and Propionibacterium spp. were susceptible to all antimicrobials tested except metronidazole. Variable results were obtained with other antimicrobial-organism combinations. Comparison of results with data from a previously published survey showed little change in susceptibility except for increased resistance of Bacteroides fragilis to ceftriaxone and Clostridium species (not C perfringens) to clindamycin. Our results update the local susceptibility profile of anaerobic bacteria and may be considered when choosing an antimicrobial agent for prophylaxis or treatment of anaerobic infections.

[Activity of doripenem against anaerobic bacteria].

Science.gov (United States)

Dubreuil, L; Neut, C; Mahieux, S; Muller-Serieys, C; Jean-Pierre, H; Marchandin, H; Soussy, C J; Miara, A

2011-04-01

This study examines the activity of doripenem, a new carbapenem compound compared with amoxicillin-clavulanic acid, piperacillin+tazobactam, imipenem, clindamycin and metronidazole against 316 anaerobes. Inoculum preparation and agar dilution method were performed according to the CLSI method for anaerobes (M11A7). At a concentration of 4μg/ml doripenem and imipenem (IMP) inhibited 122 (96 %) and 126 (99 %) strains of the Bacteroides fragilis group, respectively. In contrast, doripenem appeared more potent than IMP against Gram-positive anaerobes inhibiting at the same concentration of 4μg/ml 145/145 strains (100 %) versus 115/145 for IMP (79.3 %). Against 316 anaerobic strains, the carbapenem doripenem had an MIC(50) of 0.25μg/ml and an MIC(90) of 2μg/ml. Results were similar to those for imipenem (MIC(50) of 0.125μg/ml and MIC(90) of 4μg/ml). If we consider the resistant breakpoints of the two carbapenems as defined by EUCAST, the resistance rate for doripenem (MIC>4μg/ml) 1.6 % is similar to that of imipenem (MIC>8μg/ml) 1.3 %. Thus independently of the PK/PD parameters the two carbapenems demonstrated very close activity; doripenem was more potent on Gram-positive anaerobes and slightly less potent against Gram-negative anaerobes mainly the B. fragilis group. Further clinical studies are needed to assess its usefulness in patients. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Long-term stability of thermophilic co-digestion submerged anaerobic membrane reactor encountering high organic loading rate, persistent propionate and detectable hydrogen in biogas.

Science.gov (United States)

Qiao, Wei; Takayanagi, Kazuyuki; Niu, Qigui; Shofie, Mohammad; Li, Yu You

2013-12-01

The performance of thermophilic anaerobic co-digestion of coffee grounds and sludge using membrane reactor was investigated for 148 days, out of a total research duration of 263 days. The OLR was increased from 2.2 to 33.7 kg-COD/m(3)d and HRT was shortened from 70 to 7 days. A significant irreversible drop in pH confirmed the overload of reactor. Under a moderately high OLR of 23.6 kg-COD/m(3)d, and with HRT and influent total solids of 10 days and 150 g/L, respectively, the COD removal efficiency was 44.5%. Hydrogen in biogas was around 100-200 ppm, which resulted in the persistent propionate of 1.0-3.2g/L. The VFA consumed approximately 60% of the total alkalinity. NH4HCO3 was supplemented to maintain alkalinity. The stability of system relied on pH management under steady state. The 16SrDNA results showed that hydrogen-utilizing methanogens dominates the archaeal community. The propionate-oxidizing bacteria in bacterial community was insufficient. Copyright © 2013 Elsevier Ltd. All rights reserved.

Techniques for controlling variability in gram staining of obligate anaerobes.

Science.gov (United States)

Johnson, M J; Thatcher, E; Cox, M E

1995-01-01

Identification of anaerobes recovered from clinical samples is complicated by the fact that certain gram-positive anaerobes routinely stain gram negative; Peptostreptococcus asaccharolyticus, Eubacterium plautii, Clostridium ramosum, Clostridium symbiosum, and Clostridium clostridiiforme are among the nonconformists with regard to conventional Gram-staining procedures. Accurate Gram staining of American Type Culture Collection strains of these anaerobic bacteria is possible by implementing fixing and staining techniques within a gloveless anaerobic chamber. Under anaerobic conditions, gram-positive staining occurred in all test organisms with "quick" fixing techniques with both absolute methanol and formalin. The results support the hypothesis that, when anaerobic bacteria are exposed to oxygen, a breakdown of the physical integrity of the cell wall occurs, introducing Gram stain variability in gram-positive anaerobes. PMID:7538512

ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

Energy Technology Data Exchange (ETDEWEB)

John R. Gallagher

2001-07-31

During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from a produced-water holding pond from a municipal anaerobic digester and two salt-loving methanogenic bacteria. During start-up, the feed to the reactor contained glucose as well as typical produced-water components. When glucose was used, rapid gas production was observed. However, when glucose was eliminated and the major organic component was acetate, little gas was generated. Methane production from acetate may have been inhibited by the high salt concentrations, by sulfide, or because of the lack, despite seeding, of microbes capable of converting acetate to methane. Toluene, a minor component of the produced water (0.1 g/L) was removed in the

The challenges of anaerobic digestion and the role of biochar in optimizing anaerobic digestion.

Science.gov (United States)

Fagbohungbe, Michael O; Herbert, Ben M J; Hurst, Lois; Ibeto, Cynthia N; Li, Hong; Usmani, Shams Q; Semple, Kirk T

2017-03-01

Biochar, like most other adsorbents, is a carbonaceous material, which is formed from the combustion of plant materials, in low-zero oxygen conditions and results in a material, which has the capacity to sorb chemicals onto its surfaces. Currently, research is being carried out to investigate the relevance of biochar in improving the soil ecosystem, digestate quality and most recently the anaerobic digestion process. Anaerobic digestion (AD) of organic substrates provides both a sustainable source of energy and a digestate with the potential to enhance plant growth and soil health. In order to ensure that these benefits are realised, the anaerobic digestion system must be optimized for process stability and high nutrient retention capacity in the digestate produced. Substrate-induced inhibition is a major issue, which can disrupt the stable functioning of the AD system reducing microbial breakdown of the organic waste and formation of methane, which in turn reduces energy output. Likewise, the spreading of digestate on land can often result in nutrient loss, surface runoff and leaching. This review will examine substrate inhibition and their impact on anaerobic digestion, nutrient leaching and their environmental implications, the properties and functionality of biochar material in counteracting these challenges. Copyright © 2016 Elsevier Ltd. All rights reserved.

A simple anaerobic system for onsite treatment of domestic wastewater

African Journals Online (AJOL)

Among several anaerobic treatment processes, high rate anaerobic digesters receive great attention due to its high loading capacity and chemical oxygen demand removal rate. Up-flow anaerobic sludge blanket reactor (UASB) is getting wide acceptance among several anaerobic processes. However, its application is still ...

Net alkalinity and net acidity 1: Theoretical considerations

International Nuclear Information System (INIS)

Kirby, Carl S.; Cravotta, Charles A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO 2 , and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined 'CO 2 -acidity' is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO 2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass-action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mgL -1 as CaCO 3 (based on pH and analytical concentrations of dissolved Fe II , Fe III , Mn, and Al in mgL -1 ):acidity calculated =50{1000(10 -pH )+[2(Fe II )+3(Fe III )]/56+2(Mn) /55+3(Al)/27}underestimates contributions from HSO 4 - and H + , but overestimates the acidity due to Fe 3+ and Al 3+ . However, these errors tend to approximately cancel each other. It is demonstrated that 'net alkalinity' is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the

Net alkalinity and net acidity 1: Theoretical considerations

Science.gov (United States)

Kirby, C.S.; Cravotta, C.A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined "CO 2-acidity" is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass- action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mg L -1 as CaCO3 (based on pH and analytical concentrations of dissolved FeII, FeIII, Mn, and Al in mg L -1):aciditycalculated=50{1000(10-pH)+[2(FeII)+3(FeIII)]/56+2(Mn)/ 55+3(Al)/27}underestimates contributions from HSO4- and H+, but overestimates the acidity due to Fe3+ and Al3+. However, these errors tend to approximately cancel each other. It is demonstrated that "net alkalinity" is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation, (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the value obtained in a

Bile anaerobic bacteria detection and antibiotic susceptibility in patients with gallstone.

Science.gov (United States)

Lu, Yun; Xiang, Ting-Hai; Shi, Jing-Sen; Zhang, Bing-Yuan

2003-08-01

To detect bile anaerobic bacteria and antibiotic susceptibility in 59 patients with gallstones who had had cholecystectomy. BACT/ALERT 120 microbe detection system and SCEPTOR microbe detection system were used to detect bile anaerobic bacteria, antibiotic susceptibility. The ratio of anaerobic bacteria to the patients examined was 52.5% (31/59). Obligate anaerobe bile culture showed positive results in 4 patients. B. fragilis (37.8%) was the major type of anaerobic bacteria in bile. Most (81.8%) of anaerobic bacteria were sensitive to metronidazole, and imipenem was suitable for beta-lactamase bacteria. Culture of anaerobic bacteria in logarithmic phase can improve the positive rate of the culture. There are some relations between anaerobic infection and gallstone formation.

Anaerobes in Industrial- and Environmental Biotechnology.

Science.gov (United States)

Hatti-Kaul, Rajni; Mattiasson, Bo

Anaerobic microorganisms present in diverse ecological niches employ alternative strategies for energy conservation in the absence of oxygen which enables them to play a key role in maintaining the global cycles of carbon, nitrogen, and sulfur, and the breakdown of persistent compounds. Thereby they become useful tools in industrial and environmental biotechnology. Although anaerobes have been relatively neglected in comparison to their aerobic counterparts, with increasing knowledge about their diversity and metabolic potential and the development of genetic tools and process technologies to utilize them, we now see a rapid expansion of their applications in the society. This chapter summarizes some of the developments in the use of anaerobes as tools for biomass valorization, in production of energy carriers and chemicals, wastewater treatment, and the strong potential in soil remediation. The ability of several autotrophic anaerobes to reduce carbon dioxide is attracting growing attention as a means for developing a platform for conversion of waste gases to chemicals, materials, and biofuels.

Hydrothermal alkaline stability of bentonite barrier by concrete interstitial wastes

International Nuclear Information System (INIS)

Leguey Jimenez, S.; Cuevas Rodriguez, J.; Ramirez Martin, S.; Vigil de la villa Mencia, R.; Martin Barca, M.

2002-01-01

At present, the main source of High Level radioactive Waste (HLW) is the electrical energy production during all the steps of developing. In almost all the countries with nuclear programs, the option for the final management of HLW is the Deep Geological Repository (DGR) based on the concept of multi barrier. According to this concept, the waste is isolated from biosphere by the interposition of confinement barriers. Two of the engineering barriers in the Spanish design of DGR in granitic rock are compacted bentonite and concrete. The bentonite barrier is the backfilling and sealing material for the repository gallery, because of its mechanical and physico-chemical properties. The main qualities of concrete as a component of a multi barrier system are its low permeability, mechanical resistance and chemical properties. With regard to chemical composition of concrete, the alkaline nature of cement pore water lowers the solubility of many radioactive elements. However, structural transformation in smectite, dissolution or precipitation of minerals and, consequently, changes in the bentonite properties could occurs in the alkaline conditions generated by the cement degradation. The main objective of the present work is to evaluate the effect of concrete in the stability of Spanish reference bentonite (La Serrata of Nijar, Almeria, Spain) in conditions similar to those estimated in a DGR in granitic rock. Because of the main role of bentonite barrier in the global performance of the repository, the present study is essential to guarantee its security. (Author)

Anaerobic biotransformation of estrogens

International Nuclear Information System (INIS)

Czajka, Cynthia P.; Londry, Kathleen L.

2006-01-01

Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-α-ethynylestradiol (EE2) and 17-β-estradiol (E2) in order to understand their fate in aquatic and terrestrial environments. Cultures were established using lake water and sediment under methanogenic, sulfate-, iron-, and nitrate-reducing conditions. Anaerobic degradation of EE2 (added at 5 mg/L) was not observed in multiple trials over long incubation periods (over three years). E2 (added at 5 mg/L) was transformed to estrone (E1) under all four anaerobic conditions (99-176 μg L -1 day -1 ), but the extent of conversion was different for each electron acceptor. The oxidation of E2 to E1 was not inhibited by E1. Under some conditions, reversible inter-conversion of E2 and E1 was observed, and the final steady state concentration of E2 depended on the electron-accepting condition but was independent of the total amount of estrogens added. In addition, racemization occurred and E1 was also transformed to 17-α-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-α-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments

Bacterial population of piggery-waste anaerobic digesters

Energy Technology Data Exchange (ETDEWEB)

Hobson, P N; Shaw, B G

1974-08-01

A survey was made of the anaerobic and facultatively anaerobic bacteria present in piggery waste, digesting piggery waste and domestic anaerobic sludge used to start a piggery waste digester. An influence of the input waste was shown in that streptococci, the predominant facultatively anaerobic bacteria in the piggery waste, were the predominant bacteria in the digesting waste, and they replaced Entrobacter, predominant in the domestic sludge, when a piggery waste digestion had been established from this latter material. Cellulolytic or methanogenic bacteria could not be detected in the piggery waste but populations of these, and other hydrolytic bacteria, became established at different times during the build-up of digestion by gradual addition of piggery waste to water. The bacteria concerned in degradation of the waste constituents were all anaerobes. Production of methane from H/sub 2//CO/sub 2/, formate and butyrate could be detected in mixed cultures from dilutions of digester contents, but the only methanogenic bacterium that could be isolated in pure culture was Methanobacterium formicicum, which uses H/sub 2//CO/sub 2/ or formate only.

Alkaline sorbent injection for mercury control

Science.gov (United States)

Madden, Deborah A.; Holmes, Michael J.

2002-01-01

A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

[Application of anaerobic bacteria detection in oral and maxillofacial infection].

Science.gov (United States)

Bao, Zhen-ying; Lin, Qin; Meng, Yan-hong; He, Chun; Su, Jia-zeng; Peng, Xin

2016-02-18

To investigate the distribution and drug resistance of anaerobic bacteria in the patients with oral and maxillofacial infection. Aerobic and anaerobic bacteria cultures from 61 specimens of pus from the patients with oral and maxillofacial infection in the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology were identified. The culture type was evaluated by API 20A kit and drug resistance test was performed by Etest method. The clinical data and antibacterial agents for the treatment of the 61 cases were collected, and the final outcomes were recorded. The bacteria cultures were isolated from all the specimens, with aerobic bacteria only in 6 cases (9.8%), anaerobic bacteria only in 7 cases (11.5%), and both aerobic and anaerobic bacteria in 48 cases (78.7%). There were 55 infected cases (90.2%) with anaerobic bacteria, and 81 anaerobic bacteria stains were isolated. The highest bacteria isolation rate of Gram positive anaerobic bacteria could be found in Peptostreptococcus, Bifidobacterium and Pemphigus propionibacterium. No cefoxitin, amoxicillin/carat acid resistant strain was detected in the above three Gram positive anaerobic bacteria. The highest bacteria isolation rate of Gram negative anaerobic bacteria could be detected in Porphyromonas and Prevotella. No metronidazole, cefoxitin, amoxicillin/carat acid resistant strain was found in the two Gram negative anaerobic bacteria. In the study, 48 patients with oral and maxillofacial infection were treated according to the results of drug resistance testing, and the clinical cure rate was 81.3%. Mixed aerobic and anaerobic bacteria cultures are very common in most oral and maxillofacial infection patients. Anaerobic bacteria culture and drug resistance testing play an important role in clinical treatment.

Anaerobic biodegradability and toxicity of complex or toxicant wastewater

International Nuclear Information System (INIS)

Wills Betancur, B.A.

1995-01-01

As a first approximation to wastewater classification in susceptibility terms to treatment by anaerobic biological system, anaerobic biodegradability trials are accomplished to leached of sanitary landfill, to wastewater of coffee grain wet treatment plant and to wastewater of fumaric acid recuperation plant. In the last Plant, anaerobic toxicity trials and lethal toxicity on the Daphnia pulex micro-crustacean are made too. Anaerobic biological trials are made continuing the Wageningen University (Holland) Methodology (1.987). Lethal toxicity biological trials are made following the Standard Methods for the Examination of Water and Wastewater(18th edition, 1992). In development of this investigation project is found that fumaric acid recuperation plant leached it has a low anaerobic biodegradability, a high anaerobic toxicity and a high lethal toxicity over Daphnia pulex, for such reasons this leached is cataloged as complex and toxic wastewater. The other hand, wastewater of coffee grain wet treatment plant and wastewater of sanitary landfill they are both highly biodegradability and not-toxic, for such reasons these wastewaters are cataloged as susceptible to treatment by anaerobic biological system

Thermophilic anaerobic fermentation of olive pulp for hydrogen and methane production: modelling of the anaerobic digestion process

DEFF Research Database (Denmark)

Gavala, Hariklia N.; Skiadas, Ioannis V.; Ahring, Birgitte Kiær

2006-01-01

the olive pulp; c) subsequent anaerobic treatment of the hydrogen-effluent with the simultaneous production of methane; and d) development of a mathematical model able to describe the anaerobic digestion of the olive pulp and the effluent of hydrogen producing process. Both continuous and batch experiments...

Increased liver alkaline phosphatase and aminotransferase ...

African Journals Online (AJOL)

The effect of daily, oral administration of ethanolic extract of Khaya senegalensis stem bark (2mg/kg body weight) for 18days on the alkaline phosphatase, aspartate and alanine aminotransferase activities of rat liver and serum were investigated. Compared with the control, the activities of liver alkaline phosphatase (ALP), ...

Sample preparation in alkaline media

International Nuclear Information System (INIS)

Nobrega, Joaquim A.; Santos, Mirian C.; Sousa, Rafael A. de; Cadore, Solange; Barnes, Ramon M.; Tatro, Mark

2006-01-01

The use of tetramethylammonium hydroxide, tertiary amines and strongly alkaline reagents for sample treatment involving extraction and digestion procedures is discussed in this review. The preparation of slurries is also discussed. Based on literature data, alkaline media offer a good alternative for sample preparation involving an appreciable group of analytes in different types of samples. These reagents are also successfully employed in tailored speciation procedures wherein there is a critical dependence on maintenance of chemical forms. The effects of these reagents on measurements performed using spectroanalytical techniques are discussed. Several undesirable effects on transport and atomization processes necessitate use of the method of standard additions to obtain accurate results. It is also evident that alkaline media can improve the performance of techniques such as inductively coupled plasma mass spectrometry and accessories, such as autosamplers coupled to graphite furnace atomic absorption spectrometers

The effect of irrigated rice cropping on the alkalinity of two alkaline rice soils in the Sahel

NARCIS (Netherlands)

Asten, van P.J.A.; Zelfde, van 't J.A.; Zee, van der S.E.A.T.M.; Hammecker, C.

2004-01-01

Irrigated rice cropping is practiced to reclaim alkaline-sodic soils in many parts of the world. This practice is in apparent contrast with earlier studies in the Sahel, which suggests that irrigated rice cropping may lead to the formation of alkaline-sodic soils. Soil column experiments were done

The deep, hot biosphere: Twenty-five years of retrospection.

Science.gov (United States)

Colman, Daniel R; Poudel, Saroj; Stamps, Blake W; Boyd, Eric S; Spear, John R

2017-07-03

Twenty-five years ago this month, Thomas Gold published a seminal manuscript suggesting the presence of a "deep, hot biosphere" in the Earth's crust. Since this publication, a considerable amount of attention has been given to the study of deep biospheres, their role in geochemical cycles, and their potential to inform on the origin of life and its potential outside of Earth. Overwhelming evidence now supports the presence of a deep biosphere ubiquitously distributed on Earth in both terrestrial and marine settings. Furthermore, it has become apparent that much of this life is dependent on lithogenically sourced high-energy compounds to sustain productivity. A vast diversity of uncultivated microorganisms has been detected in subsurface environments, and we show that H 2 , CH 4 , and CO feature prominently in many of their predicted metabolisms. Despite 25 years of intense study, key questions remain on life in the deep subsurface, including whether it is endemic and the extent of its involvement in the anaerobic formation and degradation of hydrocarbons. Emergent data from cultivation and next-generation sequencing approaches continue to provide promising new hints to answer these questions. As Gold suggested, and as has become increasingly evident, to better understand the subsurface is critical to further understanding the Earth, life, the evolution of life, and the potential for life elsewhere. To this end, we suggest the need to develop a robust network of interdisciplinary scientists and accessible field sites for long-term monitoring of the Earth's subsurface in the form of a deep subsurface microbiome initiative.

Anaerobic energy metabolism in unicellular photosynthetic eukaryotes.

Science.gov (United States)

Atteia, Ariane; van Lis, Robert; Tielens, Aloysius G M; Martin, William F

2013-02-01

Anaerobic metabolic pathways allow unicellular organisms to tolerate or colonize anoxic environments. Over the past ten years, genome sequencing projects have brought a new light on the extent of anaerobic metabolism in eukaryotes. A surprising development has been that free-living unicellular algae capable of photoautotrophic lifestyle are, in terms of their enzymatic repertoire, among the best equipped eukaryotes known when it comes to anaerobic energy metabolism. Some of these algae are marine organisms, common in the oceans, others are more typically soil inhabitants. All these species are important from the ecological (O(2)/CO(2) budget), biotechnological, and evolutionary perspectives. In the unicellular algae surveyed here, mixed-acid type fermentations are widespread while anaerobic respiration, which is more typical of eukaryotic heterotrophs, appears to be rare. The presence of a core anaerobic metabolism among the algae provides insights into its evolutionary origin, which traces to the eukaryote common ancestor. The predicted fermentative enzymes often exhibit an amino acid extension at the N-terminus, suggesting that these proteins might be compartmentalized in the cell, likely in the chloroplast or the mitochondrion. The green algae Chlamydomonas reinhardtii and Chlorella NC64 have the most extended set of fermentative enzymes reported so far. Among the eukaryotes with secondary plastids, the diatom Thalassiosira pseudonana has the most pronounced anaerobic capabilities as yet. From the standpoints of genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism in C. reinhardtii remains the best characterized among photosynthetic protists. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Cripple Creek and other alkaline-related gold deposits in the Southern Rocky Mountains, USA: Influence of regional tectonics

Science.gov (United States)

Kelley, K.D.; Ludington, S.

2002-01-01

opposed to deposits to the south. Deep-seated structures of regional extent that formed during the Proterozoic allowed the magmas to rise to shallow crustal levels. Proterozoic sites of intrusions at 1.65, 1.4, and 1.1 Ga were also important precursors to alkaline-related gold deposits. Many of the larger gold deposits are located at sites of Proterozoic intrusions, and are localized at the intersection of northeast-trending ductile shear zones formed during Mesoproterozoic deformation, and an important north-trending fault formed during 1.1 Ga rifting.

Catalytic oxidation of soot over alkaline niobates

International Nuclear Information System (INIS)

Pecchi, G.; Cabrera, B.; Buljan, A.; Delgado, E.J.; Gordon, A.L.; Jimenez, R.

2013-01-01

Highlights: ► No previous reported studies about alkaline niobates as catalysts for soot oxidation. ► NaNbO 3 and KNbO 3 perovskite-type oxides show lower activation energy than other lanthanoid perovskite-type oxides. ► The alkaline niobate does not show deactivation by metal loss. - Abstract: The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N 2 adsorption, XRD, O 2 -TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO 3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO 3 > NaNbO 3 > LiNbO 3 . The RbNbO 3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO 3 , despite the lower apparent activation energy of NaNbO 3 , stress the importance of the metal nature and suggests the hypothesis that K + ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.

Comparative Detection of Alkaline Protease Production in Exiguobacterium acetylicum

International Nuclear Information System (INIS)

Gomaa, O.M.; EI Shafey, H.M.

2009-01-01

Alkaline protease is one of the most important enzymes in industry, medicine, and research. In the present work, a comparative detection for alkaline protease activity was established for instant detection of enzyme activity. Eight different alkalophilic bacterial isolates were compared based on the clear zone they produced on skim milk agar. One strain gave an absolute clear zone in 16 hours and was used for alkaline protease detection. The result of Phenotypic identification using Biology Microlog 3 identified the isolate as Exiguobacterium acetylicum. The isolate under study showed slightly different characteristics from a known Exiguobacterium acetylicum strain. The isolate tolerated alkaline conditions up to ph 11, while good growth was evident at ph 7, the maximum alkaline protease activity was observed at ph 9 which reached up to 109.01 U/ml. The alkaline activity assay using alkaline protease enzyme assay were coordinating with those obtained by conductivity; there was a relevant decrease in conductivity at the maximum increase in enzyme activity, which proved the cell membrane conductivity has a close relation to alkaline protease production. This isolate has tolerated gamma radiation, the increase in dose (up to 4 Gy) gave wider clear zones in terms of diameter and this was relevant to the conductivity measurements

Optical properties of alkaline earth borate glasses

African Journals Online (AJOL)

user

... devices; radiation shields, surgical lasers and their glass ceramic counter ... Alkaline earth oxides improve glass forming capability while heavy metal ... reports on optical properties of MO-B2O3 glasses containing alkaline earth oxides.

The IWA Anaerobic Digestion Model No 1 (ADM1)

NARCIS (Netherlands)

Batstone, D.J.; Keller, J.; Angelidaki, I.; Kalyuzhnyi, S.V.; Pavalostathis, S.G.; Rozzi, A.; Sanders, W.T.M.; Siegrist, H.; Vavilin, V.A.

2002-01-01

The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well as

The IWA Anaerobic digestion model no 1. (ADM1)

DEFF Research Database (Denmark)

Batstone, Damien J.; Keller, J.; Angelidaki, Irini

2002-01-01

The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well...

Alkaline resistant ceramics; Alkalimotstaandskraftiga keramer

Energy Technology Data Exchange (ETDEWEB)

Westberg, Stig-Bjoern [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

2001-02-01

Despite durability in several environments, ceramics and refractories can not endure alkaline environments at high temperature. An example of such an environment is when burning biofuel in modern heat and power plants in which the demand for increasing efficiency results in higher combustion temperatures and content of alkaline substances in the flue gas. Some experiences of these environments has been gained from such vastly different equipment as regenerator chambers in the glass industry and MHD-generators. The grains of a ceramic material are usually bonded together by a glassy phase which despite it frequently being a minor constituent render the materials properties and limits its use at elevated temperature. The damage is usually caused by alkaline containing low-melting phases and the decrease of the viscosity of the bonding glass phase which is caused by the alkaline. The surfaces which are exposed to the flue gas in a modern power plant are not only exposed to the high temperature but also a corroding and eroding, particle containing, gas flow of high velocity. The use of conventional refractory products is limited to 1300-1350 deg C. Higher strength and fracture toughness as well as durability against gases, slag and melts at temperatures exceeding 1700 deg C are expected of the materials of the future. Continuous transport of corrosive compounds to the surface and corrosion products from the surface as well as a suitable environment for the corrosion to occur in are prerequisites for extensive corrosion to come about. The highest corrosion rate is therefore found in a temperature interval between the dew point and the melting point of the alkaline-constituent containing compound. It is therefore important that the corrosion resistance is sufficient in the environment in which alkaline containing melts or slag may appear. In environments such as these, even under normal circumstances durable ceramics, such as alumina and silicon carbide, are attacked

Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan

Directory of Open Access Journals (Sweden)

J. Felden

2013-05-01

Full Text Available The Amon mud volcano (MV, located at 1250 m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulfate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition, and microbial activities over 3 yr, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulfide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. The low microbial activity in the hydrocarbon-vented areas of Amon MV is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer MV area is limited by hydrocarbon transport.

Acidity and alkalinity in mine drainage: Theoretical considerations

Science.gov (United States)

Kirby, Carl S.; Cravotta,, Charles A.

2004-01-01

Acidity, net acidity, and net alkalinity are widely used parameters for the characterization of mine drainage, but these terms are not well defined and are often misunderstood. Incorrect interpretation of acidity, alkalinity, and derivative terms can lead to inadequate treatment design or poor regulatory decisions. We briefly explain derivations of theoretical expressions of three types of alkalinities (caustic, phenolphthalein, and total) and acidities (mineral, CO2, and total). Theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined “CO2- acidity” is closely related to most standard titration methods used for mine drainage with an endpoint pH of 8.3, but it presents numerous interpretation problems, and it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/massaction approach and employing graphs for visualization, we explore the concept of principal components and how to assign acidity contributions to solution species, including aqueous complexes, commonly found in mine drainage. We define a comprehensive theoretical definition of acidity in mine drainage on the basis of aqueous speciation at the sample pH and the capacity of these species to undergo hydrolysis to pH 8.3. This definition indicates the computed acidity in milligrams per liter (mg L-1 ) as CaCO3 (based on pH and analytical concentrations of dissolved FeIII , FeII , Mn, and Al in mg L-1 ): Aciditycomputed = 50. (10(3-pH) + 3.CFeIII/55.8 + 2.CFeII/55.8 + 2.CMn/54.9 + 3.CAl/27.0) underestimates contributions from HSO4 - and H+ , but overestimates the acidity due to Fe3+. These errors tend to approximately cancel each other. We demonstrate that “net alkalinity” is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. We demonstrate that, for most mine-drainage solutions, a

The Experiment Study of Anaerobic Ammonia Oxidation Start-up by Using the Upflow Double Layer Anaerobic Filter

Directory of Open Access Journals (Sweden)

YAO Li

2018-02-01

Full Text Available Anammox is an efficient nitrogen removal process, but it is difficult to start-up and operate, and ananammox reactor is the efficient way to resolve this problem. The start-up of anammox reactor by upflow anaerobic filter was studied. Denitrifying sludge, anaerobic sludge, and mixed sludge was inoculated on the packing materials, respectively and an autotrophic denitrification condition was provided by the simulated wastewater influent. Along with the gradual increase of matrix concentration and hydraulic load, the microflora was converted to the anaerobic ammonium oxidation(anammoxreaction. The results showed that the anammox reaction could be started by all the three sludge, and the time of start-up of denitrifying sludge, anaerobic sludge, mixed sludge was 42, 54 days and 45 days, respectively. The best result was that inoculated with denitrifying sludge with 82.2% of the total nitrogen removal rate, which started-up quickly and nitrogen was removed efficiently. Double packing effectively improved the stability of anammox process in the reactor, in which the suitable influent concentration loading for the anammox bacteria was 270 mg·L-1 and 360 mg·L-1 for ammonia nitrogen and nitrite nitrogen, respectively, and the COD concentration could not be more than 150 mg· L-1. Furthermore, there was a coexist-effect for anaerobic ammonia oxidation and methanation in this reactor system.

Anaerobic bacteria that dechlorinate perchloroethene.

Science.gov (United States)

Fathepure, B Z; Nengu, J P; Boyd, S A

1987-01-01

In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224

Microbial Internal Storage Alters the Carbon Transformation in Dynamic Anaerobic Fermentation.

Science.gov (United States)

Ni, Bing-Jie; Batstone, Damien; Zhao, Bai-Hang; Yu, Han-Qing

2015-08-04

Microbial internal storage processes have been demonstrated to occur and play an important role in activated sludge systems under both aerobic and anoxic conditions when operating under dynamic conditions. High-rate anaerobic reactors are often operated at a high volumetric organic loading and a relatively dynamic profile, with large amounts of fermentable substrates. These dynamic operating conditions and high catabolic energy availability might also facilitate the formation of internal storage polymers by anaerobic microorganisms. However, so far information about storage under anaerobic conditions (e.g., anaerobic fermentation) as well as its consideration in anaerobic process modeling (e.g., IWA Anaerobic Digestion Model No. 1, ADM1) is still sparse. In this work, the accumulation of storage polymers during anaerobic fermentation was evaluated by batch experiments using anaerobic methanogenic sludge and based on mass balance analysis of carbon transformation. A new mathematical model was developed to describe microbial storage in anaerobic systems. The model was calibrated and validated by using independent data sets from two different anaerobic systems, with significant storage observed, and effectively simulated in both systems. The inclusion of the new anaerobic storage processes in the developed model allows for more successful simulation of transients due to lower accumulation of volatile fatty acids (correction for the overestimation of volatile fatty acids), which mitigates pH fluctuations. Current models such as the ADM1 cannot effectively simulate these dynamics due to a lack of anaerobic storage mechanisms.

Antibiotic-resistant obligate anaerobes during exacerbations of cystic fibrosis patients.

Science.gov (United States)

Worlitzsch, D; Rintelen, C; Böhm, K; Wollschläger, B; Merkel, N; Borneff-Lipp, M; Döring, G

2009-05-01

Pseudomonas aeruginosa and Staphylococcus aureus are thought to cause the majority of lung infections in patients with cystic fibrosis (CF). However, other bacterial pathogens may contribute to the pathophysiology of lung disease. Here, obligate anaerobes were identified in a cross-sectional study, and cell numbers and antibiotic susceptibilities of facultative and obligate anaerobes from 114 sputum samples from nine children and 36 adults with CF were determined. Furthermore, in 12 CF patients, we investigated whether conventional intravenous antibiotic therapy, administered during acute exacerbations, would affect the numbers of obligate anaerobes. Fifteen genera of obligate anaerobes were identified in 91% of the CF patients. Cell numbers (mean: 2.2 x 10(7) +/- standard deviation 6.9 x 10(7) CFU/mL of sputum sample) were comparable to those of P. aeruginosa and S. aureus. Staphylococcus saccharolyticus and Peptostreptococcus prevotii were most prevalent. Infection with P. aeruginosa did not increase the likelihood that obligate anaerobes are present in sputum specimens. Single obligate anaerobic species persisted for up to 11 months in sputum plugs in vivo. Patients with and without obligate anaerobes in sputum specimens did not differ in lung function. Intravenous therapy directed against P. aeruginosa during acute exacerbations increased lung function, but did not reduce the numbers of obligate anaerobes. Obligate anaerobic species differed widely in their patterns of resistance against meropenem, piperacillin-tazobactam, clindamycin, metronidazole and ceftazidime. In 58% of patients with acute exacerbations, obligate anaerobes were detected that were resistant to the antibiotics used for treatment. Antibiotic therapy, optimized to target anaerobes in addition to P. aeruginosa, may improve the management of CF lung disease.

Mechanism of quinolone resistance in anaerobic bacteria.

Science.gov (United States)

Oh, H; Edlund, C

2003-06-01

Several recently developed quinolones have excellent activity against a broad range of aerobic and anaerobic bacteria and are thus potential drugs for the treatment of serious anaerobic and mixed infections. Resistance to quinolones is increasing worldwide, but is still relatively infrequent among anaerobes. Two main mechanisms, alteration of target enzymes (gyrase and topoisomerase IV) caused by chromosomal mutations in encoding genes, or reduced intracellular accumulation due to increased efflux of the drug, are associated with quinolone resistance. These mechanisms have also been found in anaerobic species. High-level resistance to the newer broad-spectrum quinolones often requires stepwise mutations in target genes. The increasing emergence of resistance among anaerobes may be a consequence of previous widespread use of quinolones, which may have enriched first-step mutants in the intestinal tract. Quinolone resistance in the Bacteroides fragilis group strains is strongly correlated with amino acid substitutions at positions 82 and 86 in GyrA (equivalent to positions 83 and 87 of Escherichia coli). Several studies have indicated that B. fragilis group strains possess efflux pump systems that actively expel quinolones, leading to resistance. DNA gyrase seems also to be the primary target for quinolones in Clostridium difficile, since amino acid substitutions in GyrA and GyrB have been detected in resistant strains. To what extent other mechanisms, such as mutational events in other target genes or alterations in outer-membrane proteins, contribute to resistance among anaerobes needs to be further investigated.

Application of Methanobrevibacter acididurans in anaerobic digestion.

Science.gov (United States)

Savant, D V; Ranade, D R

2004-01-01

To operate anaerobic digesters successfully under acidic conditions, hydrogen utilizing methanogens which can grow efficiently at low pH and tolerate high volatile fatty acids (VFA) are desirable. An acid tolerant hydrogenotrophic methanogen viz. Methanobrevibacter acididurans isolated from slurry of an anaerobic digester running on alcohol distillery wastewater has been described earlier by this lab. This organism could grow optimally at pH 6.0. In the experiments reported herein, M. acididurans showed better methanogenesis under acidic conditions with high VFA, particularly acetate, than Methanobacterium bryantii, a common hydrogenotrophic inhabitant of anaerobic digesters. Addition of M. acididurans culture to digesting slurry of acidogenic as well as methanogenic digesters running on distillery wastewater showed increase in methane production and decrease in accumulation of volatile fatty acids. The results proved the feasibility of application of M. acididurans in anaerobic digesters.

Perspectives for anaerobic digestion

DEFF Research Database (Denmark)

Ahring, Birgitte Kiær

2003-01-01

The modern society generates large amounts of waste that represent a tremendous threat to the environment and human and animal health. To prevent and control this, a range of different waste treatment and disposal methods are used. The choice of method must always be based on maximum safety...... to the soil. Anaerobic digestion (AD) is one way of achieving this goal and it will furthermore, reduce energy consumption or may even be net energy producing. This chapter aims at provide a basic understanding of the world in which anaerobic digestion is operating today. The newest process developments...

Intraspecific variation in aerobic and anaerobic locomotion

DEFF Research Database (Denmark)

Svendsen, Jon Christian; Tirsgård, Bjørn; Cordero, Gerardo A.

2015-01-01

to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; U crit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3...... respirometry and video analysis. Results showed that anaerobic swimming costs (i.e., EPOC) increase linearly with the number of bursts in S. aurata, with each burst corresponding to 0.53 mg O2 kg(-1). Data are consistent with a previous study on striped surfperch (Embiotoca lateralis), a labriform swimmer...

Temperature Dependence of Mineral Solubility in Water. Part 2. Alkaline and Alkaline Earth Bromides

Science.gov (United States)

Krumgalz, B. S.

2018-03-01

Databases of alkaline and alkaline earth bromide solubilities in water at various temperatures were created using experimental data from publications over about the last two centuries. Statistical critical evaluation of the created databases was produced since there were enough independent data sources to justify such evaluation. The reliable experimental data were adequately described by polynomial expressions over various temperature ranges. Using the Pitzer approach for ionic activity and osmotic coefficients, the thermodynamic solubility products for the discussed bromide minerals have been calculated at various temperature intervals and also represented by polynomial expressions.

Problematic effects of antibiotics on anaerobic treatment of swine wastewater.

Science.gov (United States)

Cheng, D L; Ngo, H H; Guo, W S; Chang, S W; Nguyen, D D; Kumar, S Mathava; Du, B; Wei, Q; Wei, D

2018-05-04

Swine wastewaters with high levels of organic pollutants and antibiotics have become serious environmental concerns. Anaerobic technology is a feasible option for swine wastewater treatment due to its advantage in low costs and bioenergy production. However, antibiotics in swine wastewater have problematic effects on micro-organisms, and the stability and performance of anaerobic processes. Thus, this paper critically reviews impacts of antibiotics on pH, COD removal efficiencies, biogas and methane productions as well as the accumulation of volatile fatty acids (VFAs) in the anaerobic processes. Meanwhile, impacts on the structure of bacteria and methanogens in anaerobic processes are also discussed comprehensively. Furthermore, to better understand the effect of antibiotics on anaerobic processes, detailed information about antimicrobial mechanisms of antibiotics and microbial functions in anaerobic processes is also summarized. Future research on deeper knowledge of the effect of antibiotics on anaerobic processes are suggested to reduce their adverse environmental impacts. Copyright © 2018 Elsevier Ltd. All rights reserved.

Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

International Nuclear Information System (INIS)

Mendes, Carlos; Esquerre, Karla; Matos Queiroz, Luciano

2015-01-01

Highlights: • The behavior of a anaerobic reactor was evaluated through modeling. • Parametric sensitivity analysis was used to select most sensitive of the ADM1. • The results indicate that the ADM1 was able to predict the experimental results. • Organic load rate above of 35 kg/m 3 day affects the performance of the process. - Abstract: Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35 kg/m 3 day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge

Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

Energy Technology Data Exchange (ETDEWEB)

Mendes, Carlos, E-mail: carllosmendez@gmail.com; Esquerre, Karla, E-mail: karlaesquerre@ufba.br; Matos Queiroz, Luciano, E-mail: lmqueiroz@ufba.br

2015-01-15

Highlights: • The behavior of a anaerobic reactor was evaluated through modeling. • Parametric sensitivity analysis was used to select most sensitive of the ADM1. • The results indicate that the ADM1 was able to predict the experimental results. • Organic load rate above of 35 kg/m{sup 3} day affects the performance of the process. - Abstract: Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35 kg/m{sup 3} day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge.

Characterization of Spartina alterniflora as feedstock for anaerobic digestion

International Nuclear Information System (INIS)

Yang, Shiguan; Zheng, Zheng; Meng, Zhuo; Li, Jihong

2009-01-01

Smooth cordgrass (Spartina alterniflora), a saltmarsh plant with high production, was characterized for its potential for use as feedstock for anaerobic digestion processes. The anaerobic digestibility and biogas yield of S. alterniflora were evaluated by anaerobic batch digestion experiments performed at 35 ± 1 C at initial volatile solids (VS) of 6%. The nutrient content analysis indicated that S. alterniflora contained the required nutrition for anaerobic microorganisms, but its high C/N of 58.8, high K and Na contents of 8.1, 22.7 g kg -1 , respectively, may be disadvantageous to its anaerobic digestion. The cumulative biogas yield was determined to be 358 L kg -1 VS and the biodegradation efficiency was 45% after 60 days of digestion. The methane content of biogas increased from 53% on day 3 to around 62% after 13 days of digestion. The changes of volatile fatty acids (VFAs) indicated that the acidification of S. alterniflora was propionate-type fermentation with proportion of acetate and propionate ranging from 54.8% to 98.4%, and the hydrolysis of lignocellulose was the rate-limiting step for its anaerobic digestion. The analysis of cations suggested that K + and Mg 2+ , with the maximum concentration of 1.35 and 0.43 g L -1 in fermentation liquor, respectively, could be inhibitory to the anaerobic digestion of S. alterniflora. It is concluded that S. alterniflora can be transformed into clean energy by anaerobic digestion and the high contents of K, Na, Ca and Mg may be the inhibitory factors when S. alterniflora is digested by continuous or semi-continuous anaerobic process. (author)

Growth and Tissue Elemental Composition Response of Butterhead Lettuce (Lactuca sativa, cv. Flandria to Hydroponic Conditions at Different pH and Alkalinity

Directory of Open Access Journals (Sweden)

Tyler S. Anderson

2017-07-01

Full Text Available Biomass and tissue elemental differences were quantified for lettuce grown in deep-water conventional hydroponic conditions at two pH and alkalinity conditions. Nutrient solutions were created using inorganic salts and either reverse osmosis (RO water or municipal water with high alkalinity. Three treatments were evaluated: (a nutrient solution created with reverse osmosis (RO water and maintained at pH 5.8 (H5; (b same as H5 but maintained at pH 7.0 (H7; and (c nutrient solution created using municipal water and maintained at pH 7.0, referred to as HA7. Averaged across three trials, the HA7 and H7 treatments produced 26% less shoot fresh weight (FW than the H5 treatment with an 18% reduction in dry weight (DW. The H5 treatment had the least biomass in root FW and DW. In tissue elemental analyses, both the pH 7.0 treatments showed lower concentrations than H5 in Cu, N, Mo, and Sr, and increased concentrations in Ba, Mg, Na, and Zn. There were no differences in Al, C, Ca, Fe, K, Mn, Ni, P, S, and Si concentrations among treatments (p = 0.05. The results from this experiment can be used to isolate the effects of pH and alkalinity in aquaponic conditions where pH and alkalinity will mimic HA7 conditions.

Instrumentation in anaerobic treatment - research and practice

NARCIS (Netherlands)

Spanjers, H.; Lier, van J.B.

2006-01-01

High rate anaerobic treatment reactors are able to uncouple solids and liquid retention time, resulting in high biomass concentrations. Principal advantages of anaerobic treatment include: energy efficiency, low biomass yield, low nutrient requirement and high volumetric organic loadings. In order

Dechlorination of Aromatic Xenobiotic Compounds by Anaerobic Microorganisms

Science.gov (United States)

1988-07-01

dechlorination of 3 6C1- 2,3,7,8-TCDD have been initiated but are incomplete at this time. The sources of anaerobic dechlorinating bacteria were the...SETHUNATHAN, 1983). Active anaerobic habitatsa DDT Soil, rumen fluid, sewage sludge, sediments, microbial cultures Lindane Soil, sediments, microbial... anaerobic bacteria (Reference 24). Sediments containing relatively high levels of PCBs (> 50 ppm) all showed losses of up to one-third of the chlorine

Alternative method for determining anaerobic threshold in rowers

Directory of Open Access Journals (Sweden)

Giovani Dos Santos Cunha

2008-01-01

Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n4p367 In rowing, the standard breathing that athletes are trained to use makes it difficult, or even impossible, to detect ventilatory limits, due to the coupling of the breath with the technical movement. For this reason, some authors have proposed determining the anaerobic threshold from the respiratory exchange ratio (RER, but there is not yet consensus on what value of RER should be used. The objective of this study was to test what value of RER corresponds to the anaerobic threshold and whether this value can be used as an independent parameter for determining the anaerobic threshold of rowers. The sample comprised 23 male rowers. They were submitted to a maximal cardiorespiratory test on a rowing ergometer with concurrent ergospirometry in order to determine VO2máx and the physiological variables corresponding to their anaerobic threshold. The anaerobic threshold was determined using the Dmax (maximal distance method. The physiological variables were classified into maximum values and anaerobic threshold values. The maximal state of these rowers reached VO2 (58.2±4.4 ml.kg-1.min-1, lactate (8.2±2.1 mmol.L-1, power (384±54.3 W and RER (1.26±0.1. At the anaerobic threshold they reached VO2 (46.9±7.5 ml.kg-1.min-1, lactate (4.6±1.3 mmol.L-1, power (300± 37.8 W and RER (0.99±0.1. Conclusions - the RER can be used as an independent method for determining the anaerobic threshold of rowers, adopting a value of 0.99, however, RER should exhibit a non-linear increase above this figure.

The role of anaerobic bacteria in the cystic fibrosis airway.

Science.gov (United States)

Sherrard, Laura J; Bell, Scott C; Tunney, Michael M

2016-11-01

Anaerobic bacteria are not only normal commensals, but are also considered opportunistic pathogens and have been identified as persistent members of the lower airway community in people with cystic fibrosis of all ages and stages of disease. Currently, the role of anaerobic bacteria in cystic fibrosis lower airway disease is not well understood. Therefore, this review describes the recent studies relating to the potential pathophysiological role(s) of anaerobes within the cystic fibrosis lungs. The most frequently identified anaerobic bacteria in the lower airways are common to both cystic fibrosis and healthy lungs. Studies have shown that in cystic fibrosis, the relative abundance of anaerobes fluctuates in the lower airways with reduced lung function and increased inflammation associated with a decreased anaerobic load. However, anaerobes found within the lower airways also produce virulence factors, may cause a host inflammatory response and interact synergistically with recognized pathogens. Anaerobic bacteria are potentially members of the airway microbiota in health but could also contribute to the pathogenesis of lower airway disease in cystic fibrosis via both direct and indirect mechanisms. A personalized treatment strategy that maintains a normal microbial community may be possible in the future.

The implications of soil acidification on a future HLW repository. Pt 2. Influence on deep granitic groundwater. The Klipperaas study site as test case

International Nuclear Information System (INIS)

Wersin, P.; Bruno, J.; Laaksoharju, M.

1994-05-01

The effect of acidification on deep groundwater is assessed with a geochemical box model based on the STEADYQL code. The application of the model to the Klipperaas study site shows a remarkable agreement between observed and predicted groundwater composition and offers an adequate description of the geochemical evolution of the aquifer. Proton fluxes are shown to be controlled mainly by calcite weathering and organic carbon degradation processes. The impact of increased acidification is evaluated on the basis of various test cases and by including the soil compartment in the model framework. The results indicate that calcite weathering will be increased by a factor of two to three as a result of increased acidification. Furthermore, the calculations suggest that, once the powerful carbonate buffer is depleted, the buffer capacity is provided mainly by anaerobic respiration and ion exchange processes. Further ongoing acidic loading would lead to neutralization of alkalinity fluxes leaving the system with a very low buffering capacity towards fluctuations in proton fluxes. Estimation of time scales of aquifer acidification was assessed under the focus of calcite depletion with aid of two acidification scenarios. These predict a time range of 12400 to 370000 years for calcite depletion to take place down to 500 meters depth. It is suggested from inherent model assumptions that these estimated time scales are conservative. 53 refs

The implications of soil acidification on a future HLW repository. Pt 2. Influence on deep granitic groundwater. The Klipperaas study site as test case.

Energy Technology Data Exchange (ETDEWEB)

Wersin, P; Bruno, J [MBT Tecnologia Ambiental, Cerdanyola (Spain); Laaksoharju, M [Geopoint AB, Spaanga (Sweden)

1994-05-01

The effect of acidification on deep groundwater is assessed with a geochemical box model based on the STEADYQL code. The application of the model to the Klipperaas study site shows a remarkable agreement between observed and predicted groundwater composition and offers an adequate description of the geochemical evolution of the aquifer. Proton fluxes are shown to be controlled mainly by calcite weathering and organic carbon degradation processes. The impact of increased acidification is evaluated on the basis of various test cases and by including the soil compartment in the model framework. The results indicate that calcite weathering will be increased by a factor of two to three as a result of increased acidification. Furthermore, the calculations suggest that, once the powerful carbonate buffer is depleted, the buffer capacity is provided mainly by anaerobic respiration and ion exchange processes. Further ongoing acidic loading would lead to neutralization of alkalinity fluxes leaving the system with a very low buffering capacity towards fluctuations in proton fluxes. Estimation of time scales of aquifer acidification was assessed under the focus of calcite depletion with aid of two acidification scenarios. These predict a time range of 12400 to 370000 years for calcite depletion to take place down to 500 meters depth. It is suggested from inherent model assumptions that these estimated time scales are conservative. 53 refs.

Antimicrobial susceptibility of anaerobic bacteria in New Zealand: 1999-2003.

Science.gov (United States)

Roberts, Sally A; Shore, Keith P; Paviour, Susan D; Holland, David; Morris, Arthur J

2006-05-01

Routine susceptibility testing of all anaerobic organisms is not advocated, but it is useful for laboratories to test periodically for anaerobic organisms and provide local susceptibility data to guide therapy. This study reports the national trend of antibiotic susceptibility of clinically significant anaerobes in New Zealand. Clinical isolates were tested using standardized methods against a range of antibiotics commonly used to treat anaerobic infections. Susceptibility was determined using NCCLS criteria. The change in susceptibility trends between this study and earlier studies was measured by comparing the geometric mean of the MIC. A total of 364 anaerobes were tested. Penicillin had poor activity against Bacteroides spp., Prevotella spp., Eubacterium spp., Clostridium tertium and Veillonella spp. In general, Fusobacterium spp., Bacteroides ureolyticus, Propionibacterium spp., Clostridium perfringens and anaerobic streptococci isolates, with the exception of Peptostreptococcus anaerobius, were penicillin susceptible. Amoxicillin/clavulanate showed good activity against most anaerobes, but resistance was seen with Bacteroides fragilis group and P. anaerobius isolates. Cefoxitin was more active than cefotetan, particularly against non-B. fragilis species, Eubacterium spp. and P. anaerobius. Meropenem and imipenem showed good activity against all anaerobes, with only 2 and 4% of Bacteroides spp., respectively, showing resistance. With the exception of Propionibacterium acnes isolates, which are predictably resistant, metronidazole was active against all anaerobes tested. There has been little change in susceptibility since 1997. Metronidazole, cefoxitin, piperacillin/tazobactam and amoxicillin/clavulanate remain good empirical choices when anaerobes are expected in our setting. No clinically relevant changes in susceptibility over time were found.

The Financial Feasibility of Anaerobic Digestion for Ontario's Livestock Industries

OpenAIRE

Weersink, Alfons; Mallon, Shawn

2007-01-01

This report is an investigation of the financial feasibility of farm based anaerobic digestion investments under Ontario's Standard Offer Contract electricity prices. Using Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) Agricultural Anaerobic Digestion Calculation Spreadsheet (AADCS) anaerobic digestion inputs, outputs, cost and revenues were estimated and used to conduct a financial analysis on the feasibility of four sized farm base anaerobic digestion investments. The res...

Metagenomic analysis and metabolite profiling of deep-sea sediments from the Gulf of Mexico following the Deepwater Horizon oil spill

Directory of Open Access Journals (Sweden)

Nikole Elizabeth Kimes

2013-03-01

Full Text Available Marine subsurface environments, such as deep-sea sediments, house abundant and diverse microbial communities that are believed to influence large-scale geochemical processes. These processes include the biotransformation and mineralization of numerous petroleum constituents. Thus, microbial communities in the Gulf of Mexico are thought to be responsible for the intrinsic bioremediation of crude oil released by the Deepwater Horizon (DWH oil spill. While hydrocarbon contamination is known to enrich for aerobic, oil-degrading bacteria in deep-seawater habitats, relatively little is known about the response of communities in deep-sea sediments, where low oxygen levels may hinder such a response. Here, we examined the hypothesis that increased hydrocarbon exposure results in an altered sediment microbial community structure that reflects the prospects for oil biodegradation under the prevailing conditions. We explore this hypothesis using metagenomic analysis and metabolite profiling of deep-sea sediment samples following the DWH oil spill. The presence of aerobic microbial communities and associated functional genes was consistent among all samples, whereas, a greater number of Deltaproteobacteria and anaerobic functional genes were found in sediments closest to the DWH blowout site. Metabolite profiling also revealed a greater number of putative metabolites in sediments surrounding the blowout zone relative to a background site located 127 km away. The mass spectral analysis of the putative metabolites revealed that alkylsuccinates remained below detection levels, but a homologous series of benzylsuccinates (with carbon chain lengths from 5 to 10 could be detected. Our findings suggest that increased exposure to hydrocarbons enriches for Deltaproteobacteria, which are known to be capable of anaerobic hydrocarbon metabolism. We also provide evidence for an active microbial community metabolizing aromatic hydrocarbons in deep-sea sediments of the

Exploring frontiers of the deep biosphere through scientific ocean drilling

Science.gov (United States)

Inagaki, F.; D'Hondt, S.; Hinrichs, K. U.

2015-12-01

Since the first deep biosphere-dedicated Ocean Drilling Program (ODP) Leg 201 using the US drill ship JOIDES Resolution in 2002, scientific ocean drilling has offered unique opportunities to expand our knowledge of the nature and extent of the deep biosphere. The latest estimate of the global subseafloor microbial biomass is ~1029cells, accounting for 4 Gt of carbon and ~1% of the Earth's total living biomass. The subseafloor microbial communities are evolutionarily diverse and their metabolic rates are extraordinarily slow. Nevertheless, accumulating activity most likely plays a significant role in elemental cycles over geological time. In 2010, during Integrated Ocean Drilling Program (IODP) Expedition 329, the JOIDES Resolutionexplored the deep biosphere in the open-ocean South Pacific Gyre—the largest oligotrophic province on our planet. During Expedition 329, relatively high concentrations of dissolved oxygen and significantly low biomass of microbial populations were observed in the entire sediment column, indicating that (i) there is no limit to life in open-ocean sediment and (ii) a significant amount of oxygen reaches through the sediment to the upper oceanic crust. This "deep aerobic biosphere" inhabits the sediment throughout up to ~37 percent of the world's oceans. The remaining ~63 percent of the oceans is comprised of higher productivity areas that contain the "deep anaerobic biosphere". In 2012, during IODP Expedition 337, the Japanese drill ship Chikyu explored coal-bearing sediments down to 2,466 meters below the seafloor off the Shimokita Peninsula, Japan. Geochemical and microbiological analyses consistently showed the occurrence of methane-producing communities associated with the coal beds. Cell concentrations in deep sediments were notably lower than those expected from the global regression line, implying that the bottom of the deep biosphere is approached in these beds. Taxonomic composition of the deep coal-bearing communities profoundly

Corrosion properties of HLW and spent fuel overpacks in highly alkaline environments

International Nuclear Information System (INIS)

Kursten, B.

2009-01-01

Throughout the world, deep geological disposal in stable rocks with low groundwater flow is considered for the long-term management of long-lived radioactive waste (vitrified high-level waste - VHLW - and spent fuel - SF).The main advantage of the SC design, with respect to corrosion, is that under the predicted conditions (i.e. highly alkaline concrete buffer), the carbon steel overpack is expected to undergo uniform corrosion (passive dissolution). The key objective of this study is to demonstrate that the carbon steel overpack will be able to ensure complete containment of the radioactivity at least during the thermal phase, this is the period during which the temperature of the host rock is expected to lie above the range of temperatures within which nominal radionuclide migration properties can be relied upon

Method for anaerobic fermentation and biogas production

DEFF Research Database (Denmark)

2013-01-01

The present invention relates to a method for biomass processing, anaerobic fermentation of the processed biomass, and the production biogas. In particular, the invention relates to a system and method for generating biogas from anaerobic fermentation of processed organic material that comprises...

Integrated anaerobic and aerobic treatment of sewage

NARCIS (Netherlands)

Wang, K.

1994-01-01

This thesis describes results of investigations dealing with sequential concept of anaerobic-aerobic treatment of municipal wastewater. The main purposes of the study were 1) to develop a proper anaerobic hydrolytic pretreatment unit, consisting of a Hydrolysis Upflow Sludge Bed (HUSB-)

Identification of a conserved protein involved in anaerobic unsaturated fatty acid synthesis in Neiserria gonorrhoeae: implications for facultative and obligate anaerobes that lack FabA

Science.gov (United States)

Isabella, Vincent M.; Clark, Virginia L.

2011-01-01

SUMMARY Transcriptome analysis of the facultative anaerobe, Neisseria gonorrhoeae, revealed that many genes of unknown function were induced under anaerobic conditions. Mutation of one such gene, NGO1024, encoding a protein belonging to the 2-nitropropane dioxygenase-like superfamiliy of proteins, was found to result in an inability of gonococci to grow anaerobically. Anaerobic growth of an NG1024 mutant was restored upon supplementation with unsaturated fatty acids (UFA), but not with the saturated fatty acid palmitate. Gonococcal fatty acid profiles confirmed that NGO1024 was involved in UFA synthesis anaerobically, but not aerobically, demonstrating that gonococci contain two distinct pathways for the production of UFAs, with a yet unidentified aerobic mechanism, and an anaerobic mechanism involving NGO1024. Expression of genes involved in classical anaerobic UFA synthesis, fabA, fabM, and fabB, was toxic in gonococci and unable to complement a NGO1024 mutation, suggesting that the chemistry involved in gonococcal anaerobic UFA synthesis is distinct from that of the classical pathway. NGO1024 homologs, which we suggest naming UfaA, form a distinct lineage within the 2-nitropropane dioxygenase-like superfamily, and are found in many facultative and obligate anaerobes that produce UFAs but lack fabA, suggesting that UfaA is part of a widespread pathway involved in UFA synthesis. PMID:21895795

HIGH-RATE ANAEROBIC TREATMENT OF ALCOHOLIC WASTEWATERS

Directory of Open Access Journals (Sweden)

Florencio L.

1997-01-01

Full Text Available Modern high-rate anaerobic wastewater treatment processes are rapidly becoming popular for industrial wastewater treatment. However, until recently stable process conditions could not be guaranteed for alcoholic wastewaters containing higher concentrations of methanol. Although methanol can be directly converted into methane by methanogens, under specific conditions it can also be converted into acetate and butyrate by acetogens. The accumulation of volatile fatty acids can lead to reactor instability in a weakly buffered reactor. Since this process was insufficiently understood, the application of high-rate anaerobic reactors was highly questionable. This research investigated the environmental factors that are of importance in the predominance of methylotrophic methanogens over acetogens in a natural mixed culture during anaerobic wastewater treatment in upflow anaerobic sludge bed reactors. Technological and microbiological aspects were investigated. Additionally, the route by which methanol is converted into methane is also presented

Alkaline pretreatment of Mexican pine residues for bioethanol ...

African Journals Online (AJOL)

Alkaline pretreatment of Mexican pine residues for bioethanol production. ... Keywords: Lignocellulosic biomass, alkaline pretreatment, enzymatic hydrolysis, fermentable sugars, fermentation. African Journal of Biotechnology Vol. 12(31), pp.

Transcriptomes and expression profiling of deep-sea corals from the Red Sea provide insight into the biology of azooxanthellate corals.

Science.gov (United States)

Yum, Lauren K; Baumgarten, Sebastian; Röthig, Till; Roder, Cornelia; Roik, Anna; Michell, Craig; Voolstra, Christian R

2017-07-25

Despite the importance of deep-sea corals, our current understanding of their ecology and evolution is limited due to difficulties in sampling and studying deep-sea environments. Moreover, a recent re-evaluation of habitat limitations has been suggested after characterization of deep-sea corals in the Red Sea, where they live at temperatures of above 20 °C at low oxygen concentrations. To gain further insight into the biology of deep-sea corals, we produced reference transcriptomes and studied gene expression of three deep-sea coral species from the Red Sea, i.e. Dendrophyllia sp., Eguchipsammia fistula, and Rhizotrochus typus. Our analyses suggest that deep-sea coral employ mitochondrial hypometabolism and anaerobic glycolysis to manage low oxygen conditions present in the Red Sea. Notably, we found expression of genes related to surface cilia motion that presumably enhance small particle transport rates in the oligotrophic deep-sea environment. This is the first study to characterize transcriptomes and in situ gene expression for deep-sea corals. Our work offers several mechanisms by which deep-sea corals might cope with the distinct environmental conditions present in the Red Sea As such, our data provide direction for future research and further insight to organismal response of deep-sea coral to environmental change and ocean warming.

Transcriptomes and expression profiling of deep-sea corals from the Red Sea provide insight into the biology of azooxanthellate corals

KAUST Repository

Yum, Lauren

2017-07-19

Despite the importance of deep-sea corals, our current understanding of their ecology and evolution is limited due to difficulties in sampling and studying deep-sea environments. Moreover, a recent re-evaluation of habitat limitations has been suggested after characterization of deep-sea corals in the Red Sea, where they live at temperatures of above 20 °C at low oxygen concentrations. To gain further insight into the biology of deep-sea corals, we produced reference transcriptomes and studied gene expression of three deep-sea coral species from the Red Sea, i.e. Dendrophyllia sp., Eguchipsammia fistula, and Rhizotrochus typus. Our analyses suggest that deep-sea coral employ mitochondrial hypometabolism and anaerobic glycolysis to manage low oxygen conditions present in the Red Sea. Notably, we found expression of genes related to surface cilia motion that presumably enhance small particle transport rates in the oligotrophic deep-sea environment. This is the first study to characterize transcriptomes and in situ gene expression for deep-sea corals. Our work offers several mechanisms by which deep-sea corals might cope with the distinct environmental conditions present in the Red Sea As such, our data provide direction for future research and further insight to organismal response of deep-sea coral to environmental change and ocean warming.

Transcriptomes and expression profiling of deep-sea corals from the Red Sea provide insight into the biology of azooxanthellate corals

KAUST Repository

Yum, Lauren; Baumgarten, Sebastian; Rö thig, Till; Roder, Cornelia; Roik, Anna Krystyna; Michell, Craig; Voolstra, Christian R.

2017-01-01

Despite the importance of deep-sea corals, our current understanding of their ecology and evolution is limited due to difficulties in sampling and studying deep-sea environments. Moreover, a recent re-evaluation of habitat limitations has been suggested after characterization of deep-sea corals in the Red Sea, where they live at temperatures of above 20 °C at low oxygen concentrations. To gain further insight into the biology of deep-sea corals, we produced reference transcriptomes and studied gene expression of three deep-sea coral species from the Red Sea, i.e. Dendrophyllia sp., Eguchipsammia fistula, and Rhizotrochus typus. Our analyses suggest that deep-sea coral employ mitochondrial hypometabolism and anaerobic glycolysis to manage low oxygen conditions present in the Red Sea. Notably, we found expression of genes related to surface cilia motion that presumably enhance small particle transport rates in the oligotrophic deep-sea environment. This is the first study to characterize transcriptomes and in situ gene expression for deep-sea corals. Our work offers several mechanisms by which deep-sea corals might cope with the distinct environmental conditions present in the Red Sea As such, our data provide direction for future research and further insight to organismal response of deep-sea coral to environmental change and ocean warming.

Alkaline rocks and the occurrence of uranium

International Nuclear Information System (INIS)

Hambleton-Jones, B.B.; Toens, P.D.

1980-10-01

Many alkaline complexes contain uranium and other minerals in low concentrations and are regarded as constituting valuable potential reserves. Certain complex metallurgical problems, however, remain to be solved. Alkaline rocks occur in a number of forms and environments and it is noted that they are generated during periods of geological quiescence emplaced mainly in stable aseismic areas. Many occur along the extensions of oceanic transform faults beneath the continental crust and the application of this concept to areas not currently known to host alkaline complexes may prove useful in identifying potential target areas for prospecting operations [af

Application of alkaline waterflooding to a high acidity crude oil

Energy Technology Data Exchange (ETDEWEB)

Sayyouh, M.H. (King Sand Univ., Riyadh (SA). Petroleum Engineering Dept.); Abdel-Waly, A.; Osman, A. (Cairo Univ. (EG). Petroleum Engineering Dept.); Awara, A.Z. (Geisum Oil Company, Cairo (EG))

The enhanced recovery of a high acidity crude oil (South Geisum crude) by alkaline solutions is studied. Acidity, interfacial tension, and contact angle, were investigated. Displacement tests were carried out to study the effect of alkaline slug concentration, slug size, oil alkali type, temperature and viscosity on recovery. The interfacial tension between crude oil and formation water decreases with increasing alkaline concentration until a minimum, after which it increases again. Contact angle measurements indicated oil-wetting conditions that increase by the addition of alkaline solutions. At the early stages of displacement, oil recovery increases with increasing alkaline concentration until a maximum at 4% by weight NaOH concentration. Also, at such early stages, an excessive increase in alkaline concentration results in lower oil recovery. On the other hand, after the injection of many pore volumes of water, oil recovery is almost the same regardless of the alkaline concentration. Oil recovery increases with increasing alkaline slug size until a maximum at 15% PV. Sodium hydroxide slugs produce more oil recovery than sodium carbonate slugs. Oil recovery increases with increasing temperature (from 25 to 55{sup 0}C) and decreasing oil viscosity.

Applicability and trends of anaerobic granular sludge treatment processes

International Nuclear Information System (INIS)

Lim, Seung Joo; Kim, Tak-Hyun

2014-01-01

Anaerobic granular sludge treatment processes have been continuously developed, although the anaerobic sludge granulation process was not clearly understood. In this review, an upflow anaerobic sludge blanket (UASB), an expanded granule sludge blanket (EGSB), and a static granular bed reactor (SGBR) were introduced as components of a representative anaerobic granular sludge treatment processes. The characteristics and application trends of each reactor were presented. The UASB reactor was developed in the late 1970s and its use has been rapidly widespread due to the excellent performance. With the active granules, this reactor is able to treat various high-strength wastewaters as well as municipal wastewater. Most soluble industrial wastewaters can be efficiently applied using a UASB. The EGSB reactor was developed owing to give more chance to contact between wastewater and the granules. Dispersed sludge is separated from mature granules using the rapid upward velocity in this reactor. The EGSB reactor shows the excellent performance in treating low-strength and/or high-strength wastewater, especially under low temperatures. The SGBR, developed at Iowa State University, is one of anaerobic granular sludge treatment processes. Although the configuration of the SGBR is very simple, the performance of this system is similar to that of the UASB or EGSB reactor. The anaerobic sludge granulation processes showed excellent performance for various wastewaters at a broad range of organic loading rate in lab-, pilot-scale tests. This leads to erect thousands of full-scale granular processes, which has been widely operated around the world. -- Highlights: • Anaerobic sludge granulation is a key parameter for maintaining granular processes. • Anaerobic granular digestion processes are applicable for various wastewaters. • The UASB is an economic high-rate anaerobic granular process. • The EGSB can treat high-strength wastewater using expanding granules. • The SGBR is

Redundancy in Anaerobic Digestion Microbiomes during Disturbances by the Antibiotic Monensin

Science.gov (United States)

Spirito, Catherine M.; Daly, Sarah E.; Werner, Jeffrey J.

2018-01-01

ABSTRACT The antibiotic monensin is fed to dairy cows to increase milk production efficiency. A fraction of this monensin is excreted into the cow manure. Previous studies have found that cow manure containing monensin can negatively impact the performance of anaerobic digesters, especially upon first introduction. Few studies have examined whether the anaerobic digester microbiome can adapt to monensin during the operating time. Here, we conducted a long-term time series study of four lab-scale anaerobic digesters fed with cow manure. We examined changes in both the microbiome composition and function of the anaerobic digesters when subjected to the dairy antibiotic monensin. In our digesters, monensin was not rapidly degraded under anaerobic conditions. The two anaerobic digesters that were subjected to manure from monensin feed-dosed cows exhibited relatively small changes in microbiome composition and function due to relatively low monensin concentrations. At higher concentrations of monensin, which we dosed directly to control manure (from dairy cows without monensin), we observed major changes in the microbiome composition and function of two anaerobic digesters. A rapid introduction of monensin to one of these anaerobic digesters led to the impairment of methane production. Conversely, more gradual additions of the same concentrations of monensin to the other anaerobic digester led to the adaptation of the anaerobic digester microbiomes to the relatively high monensin concentrations. A member of the candidate OP11 (Microgenomates) phylum arose in this anaerobic digester and appeared to be redundant with certain Bacteroidetes phylum members, which previously were dominating. IMPORTANCE Monensin is a common antibiotic given to dairy cows in the United States and is partly excreted with dairy manure. An improved understanding of how monensin affects the anaerobic digester microbiome composition and function is important to prevent process failure for farm

Anaerobic exercise - Induced changes in serum mineral ...

African Journals Online (AJOL)

Anaerobic exercise, a non 02 – dependent energy metabolism leads to transient metabolic changes, which are corrected gradually by homestatic mechanism. We investigated in eight male subjects, the effects of anaerobic exercise after a day sedentary activity on serum mineral concentration. There was significant ...

In-situ biogas upgrading during anaerobic digestion of food waste amended with walnut shell biochar at bench scale.

Science.gov (United States)

Linville, Jessica L; Shen, Yanwen; Ignacio-de Leon, Patricia A; Schoene, Robin P; Urgun-Demirtas, Meltem

2017-06-01

A modified version of an in-situ CO 2 removal process was applied during anaerobic digestion of food waste with two types of walnut shell biochar at bench scale under batch operating mode. Compared with the coarse walnut shell biochar, the fine walnut shell biochar has a higher ash content (43 vs. 36 wt%) and higher concentrations of calcium (31 vs. 19 wt% of ash), magnesium (8.4 vs. 5.6 wt% of ash) and sodium (23.4 vs. 0.3 wt% of ash), but a lower potassium concentration (0.2 vs. 40% wt% of ash). The 0.96-3.83 g biochar (g VS added ) -1 fine walnut shell biochar amended digesters produced biogas with 77.5%-98.1% CH 4 content by removing 40%-96% of the CO 2 compared with the control digesters at mesophilic and thermophilic temperature conditions. In a direct comparison at 1.83 g biochar (g VS added ) -1 , the fine walnut shell biochar amended digesters (85.7% CH 4 content and 61% CO 2 removal) outperformed the coarse walnut shell biochar amended digesters (78.9% CH 4 content and 51% CO 2 removal). Biochar addition also increased alkalinity as CaCO 3 from 2800 mg L -1 in the control digesters to 4800-6800 mg L -1 , providing process stability for food waste anaerobic digestion.

ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER; TOPICAL

International Nuclear Information System (INIS)

John R. Gallagher

2001-01-01

During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from a produced-water holding pond from a municipal anaerobic digester and two salt-loving methanogenic bacteria. During start-up, the feed to the reactor contained glucose as well as typical produced-water components. When glucose was used, rapid gas production was observed. However, when glucose was eliminated and the major organic component was acetate, little gas was generated. Methane production from acetate may have been inhibited by the high salt concentrations, by sulfide, or because of the lack, despite seeding, of microbes capable of converting acetate to methane. Toluene, a minor component of the produced water (0.1 g/L) was removed in the

Assessing ocean alkalinity for carbon sequestration

Science.gov (United States)

Renforth, Phil; Henderson, Gideon

2017-09-01

Over the coming century humanity may need to find reservoirs to store several trillions of tons of carbon dioxide (CO2) emitted from fossil fuel combustion, which would otherwise cause dangerous climate change if it were left in the atmosphere. Carbon storage in the ocean as bicarbonate ions (by increasing ocean alkalinity) has received very little attention. Yet recent work suggests sufficient capacity to sequester copious quantities of CO2. It may be possible to sequester hundreds of billions to trillions of tons of C without surpassing postindustrial average carbonate saturation states in the surface ocean. When globally distributed, the impact of elevated alkalinity is potentially small and may help ameliorate the effects of ocean acidification. However, the local impact around addition sites may be more acute but is specific to the mineral and technology. The alkalinity of the ocean increases naturally because of rock weathering in which >1.5 mol of carbon are removed from the atmosphere for every mole of magnesium or calcium dissolved from silicate minerals (e.g., wollastonite, olivine, and anorthite) and 0.5 mol for carbonate minerals (e.g., calcite and dolomite). These processes are responsible for naturally sequestering 0.5 billion tons of CO2 per year. Alkalinity is reduced in the ocean through carbonate mineral precipitation, which is almost exclusively formed from biological activity. Most of the previous work on the biological response to changes in carbonate chemistry have focused on acidifying conditions. More research is required to understand carbonate precipitation at elevated alkalinity to constrain the longevity of carbon storage. A range of technologies have been proposed to increase ocean alkalinity (accelerated weathering of limestone, enhanced weathering, electrochemical promoted weathering, and ocean liming), the cost of which may be comparable to alternative carbon sequestration proposals (e.g., $20-100 tCO2-1). There are still many

catalysed oxidation of atenolol by alkaline permanganate

Indian Academy of Sciences (India)

Unknown

Abstract. Kinetics of ruthenium (III) catalyzed oxidation of atenolol by permanganate in alkaline medium at constant ionic strength of 0⋅30 mol dm3 has been studied spectrophotometrically using a rapid kinetic accessory. Reaction between permanganate and atenolol in alkaline medium exhibits 1 : 8 stoichiometry.

Microbial diversity in a permanently cold and alkaline environment in Greenland.

Science.gov (United States)

Glaring, Mikkel A; Vester, Jan K; Lylloff, Jeanette E; Al-Soud, Waleed Abu; Sørensen, Søren J; Stougaard, Peter

2015-01-01

The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C) and alkaline (above pH 10) environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic representatives of the Firmicutes and Bacteroidetes. The results suggest a stratification of the ikaite columns similar to that of classical soda lakes, with a light-exposed surface inhabited by primary producers and an anoxic subsurface. This was further supported by identification of major taxonomic groups with close relatives in soda lake environments, including members of the genera Rhodobaca, Dethiobacter, Thioalkalivibrio and Tindallia, as well as very abundant groups related to uncharacterised environmental sequences originally isolated from Mono Lake in California.

Anaerobic Digestion Modeling: from One to Several Bacterial Populations

Directory of Open Access Journals (Sweden)

Iván D. Ramírez-Rivas

2013-11-01

Full Text Available Anaerobic digestion systems are complex processes that unfortunately often suffer from instability causing digester failure. In order to be able to design, optimizing and operate efficiently anaerobic digestion systems, appropriate control strategies need to be designed. Such strategies require, in general, the development of mathematical models. The anaerobic digestion process comprises a complex network of sequential and parallel reactions of biochemical and physicochemical nature. Usually, such reactions contain a particular step, the so called rate-limiting step which, being the slowest, limits the reaction rate of the overall process. The first attempts for modeling anaerobic digestion led to models describing only the limiting step. However, over a wide range of operating conditions, the limiting step is not always the same. It may depend on wastewater characteristics, hydraulic loading, temperature, etc. It is apparent that the "limiting step hypothesis" leads to simple and readily usable models. Such models, however, do not describe very well the digester behavior, especially under transient operating conditions. This work reviews the current state-of-the-art in anaerobic digestion modeling. We give a brief description of the key anaerobic digestion models that have been developed so far for describing biomass growth systems, including the International Water Association’s Anaerobic Digestion Model 1 (ADM1 and we identify the areas that require further research endeavors.

Alternative method for determining anaerobic threshold in rowers

Directory of Open Access Journals (Sweden)

Giovani dos Santos Cunha

2008-12-01

Full Text Available In rowing, the standard breathing that athletes are trained to use makes it difficult, or even impossible, to detectventilatory limits, due to the coupling of the breath with the technical movement. For this reason, some authors have proposeddetermining the anaerobic threshold from the respiratory exchange ratio (RER, but there is not yet consensus on what valueof RER should be used. The objective of this study was to test what value of RER corresponds to the anaerobic thresholdand whether this value can be used as an independent parameter for determining the anaerobic threshold of rowers. Thesample comprised 23 male rowers. They were submitted to a maximal cardiorespiratory test on a rowing ergometer withconcurrent ergospirometry in order to determine VO2máx and the physiological variables corresponding to their anaerobicthreshold. The anaerobic threshold was determined using the Dmax (maximal distance method. The physiological variableswere classified into maximum values and anaerobic threshold values. The maximal state of these rowers reached VO2(58.2±4.4 ml.kg-1.min-1, lactate (8.2±2.1 mmol.L-1, power (384±54.3 W and RER (1.26±0.1. At the anaerobic thresholdthey reached VO2 (46.9±7.5 ml.kg-1.min-1, lactate (4.6±1.3 mmol.L-1, power (300± 37.8 W and RER (0.99±0.1. Conclusions- the RER can be used as an independent method for determining the anaerobic threshold of rowers, adopting a value of0.99, however, RER should exhibit a non-linear increase above this figure.

Early anaerobic metabolisms

DEFF Research Database (Denmark)

Canfield, Donald Eugene; Rosing, Minik T; Bjerrum, Christian

2006-01-01

probably driven by the cycling of H2 and Fe2+ through primary production conducted by anoxygenic phototrophs. Interesting and dynamic ecosystems would have also been driven by the microbial cycling of sulphur and nitrogen species, but their activity levels were probably not so great. Despite the diversity......Before the advent of oxygenic photosynthesis, the biosphere was driven by anaerobic metabolisms. We catalogue and quantify the source strengths of the most probable electron donors and electron acceptors that would have been available to fuel early-Earth ecosystems. The most active ecosystems were...... of potential early ecosystems, rates of primary production in the early-Earth anaerobic biosphere were probably well below those rates observed in the marine environment. We shift our attention to the Earth environment at 3.8Gyr ago, where the earliest marine sediments are preserved. We calculate, consistent...

Biochemistry and physiology of anaerobic bacteria

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-05-18

We welcome you to The Power of Anaerobes. This conference serves two purposes. One is to celebrate the life of Harry D. Peck, Jr.,who was born May 18, 1927 and would have celebrated his 73rd birthday at this conference. He died November 20, 1998. The second is to gather investigators to exchange views within the realm of anaerobic microbiology, an area in which tremendous progress has been seen during recent years. It is sufficient to mention discoveries of a new form of life (the archaea), hyper or extreme thermophiles, thermophilic alkaliphiles and anaerobic fungi. With these discoveries has come a new realization about physiological and metabolic properties of microorganisms, and this in turn has demonstrated their importance for the development, maintenance and sustenance of life on Earth.

Energy production by anaerobic treatment of cheese whey

Energy Technology Data Exchange (ETDEWEB)

Peano, L.; Ciciarelli, R.; Comino, E.; Gard, P. A.

2009-07-01

Anaerobic treatment and methane generation potential of cheese whey, diluted with mud, were determined in the digester of an existing wastewater treatment plant in Switzerland. Lactose, main sugar in cheese whey, can be a useful indicator to evaluate serum anaerobic treatment. Conventional parameters of anaerobic digestion (Volatile Matter, Dry Matter, Fatty Volatile Acids, total Alkali metric Title) were measured after the introduction of different whey/sludge ratio demonstrating that, despite an overcharge of whey digester, its stability is never compromised. (Author)

The anaerobic corrosion of carbon steel in concrete

International Nuclear Information System (INIS)

Naish, C.C.; Balkwill, P.H.; O'Brien, T.M.; Taylor, K.J.; Marsh, G.P.

1991-01-01

This is the final report of a 2 year programme aimed at (1) determining the rate of anaerobic corrosion of steel in concrete, (2) investigating the nature of the corrosion products formed on carbon steel embedded in cementitious material under anaerobic conditions and (3) evaluating the effect of hydrogen over-pressures on the rate of anaerobic corrosion. All experiments have been carried out at temperatures in the range 20-30 0 C, ie ambient conditions. 4 refs.; 19 figs.; 6 tabs

Energy production by anaerobic treatment of cheese whey

International Nuclear Information System (INIS)

Peano, L.; Ciciarelli, R.; Comino, E.; Gard, P. A.

2009-01-01

Anaerobic treatment and methane generation potential of cheese whey, diluted with mud, were determined in the digester of an existing wastewater treatment plant in Switzerland. Lactose, main sugar in cheese whey, can be a useful indicator to evaluate serum anaerobic treatment. Conventional parameters of anaerobic digestion (Volatile Matter, Dry Matter, Fatty Volatile Acids, total Alkali metric Title) were measured after the introduction of different whey/sludge ratio demonstrating that, despite an overcharge of whey digester, its stability is never compromised. (Author)

Contribution of anaerobic energy expenditure to whole body thermogenesis

Directory of Open Access Journals (Sweden)

Scott Christopher B

2005-06-01

Full Text Available Abstract Heat production serves as the standard measurement for the determination of energy expenditure and efficiency in animals. Estimations of metabolic heat production have traditionally focused on gas exchange (oxygen uptake and carbon dioxide production although direct heat measurements may include an anaerobic component particularly when carbohydrate is oxidized. Stoichiometric interpretations of the ratio of carbon dioxide production to oxygen uptake suggest that both anaerobic and aerobic heat production and, by inference, all energy expenditure – can be accounted for with a measurement of oxygen uptake as 21.1 kJ per liter of oxygen. This manuscript incorporates contemporary bioenergetic interpretations of anaerobic and aerobic ATP turnover to promote the independence of these disparate types of metabolic energy transfer: each has different reactants and products, uses dissimilar enzymes, involves different types of biochemical reactions, takes place in separate cellular compartments, exploits different types of gradients and ultimately each operates with distinct efficiency. The 21.1 kJ per liter of oxygen for carbohydrate oxidation includes a small anaerobic heat component as part of anaerobic energy transfer. Faster rates of ATP turnover that exceed mitochondrial respiration and that are supported by rapid glycolytic phosphorylation with lactate production result in heat production that is independent of oxygen uptake. Simultaneous direct and indirect calorimetry has revealed that this anaerobic heat does not disappear when lactate is later oxidized and so oxygen uptake does not adequately measure anaerobic efficiency or energy expenditure (as was suggested by the "oxygen debt" hypothesis. An estimate of anaerobic energy transfer supplements the measurement of oxygen uptake and may improve the interpretation of whole-body energy expenditure.

Fate of N-nitrosomorpholine in an anaerobic aquifer used for managed aquifer recharge: a column study.

Science.gov (United States)

Pitoi, M M; Patterson, B M; Furness, A J; Bastow, T P; McKinley, A J

2011-04-01

The fate of N-nitrosomorpholine (NMOR) was evaluated at microgram and nanogram per litre concentrations. Experiments were undertaken to simulate the passage of groundwater contaminants through a deep anaerobic pyritic aquifer system, as part of a managed aquifer recharge (MAR) strategy. Sorption studies demonstrated the high mobility of NMOR in the Leederville aquifer system, with retardation coefficients between 1.2 and 1.6. Degradation studies from a 351 day column experiment and a 506 day stop-flow column experiment showed an anaerobic biologically induced reductive degradation process which followed first order kinetics. A biological lag-time of less than 3 months and a transient accumulation of morpholine (MOR) were also noted during the degradation. Comparable half-life degradation rates of 40-45 days were observed over three orders of magnitude in concentration (200 ng L(-1) to 650 μg L(-1)). An inhibitory effect on microorganism responsible to the biodegradation of NMOR at 650 μg L(-1) or a threshold effect at 200 ng L(-1) was not observed during these experiments. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Starch-degrading enzymes from anaerobic non-clostridial bacteria

Energy Technology Data Exchange (ETDEWEB)

Weber, H; Schepers, H J; Troesch, W [Fraunhofer-Institut fuer Grenzflaechen- und Bioverfahrenstechnik (IGB), Stuttgart (Germany, F.R.)

1990-08-01

A number of meso- and thermophilic anaerobic starch-degrading non-spore-forming bacteria have been isolated. All the isolates belonging to different genera are strictly anaerobic, as indicated by a catalase-negative reaction, and produce soluble starch-degrading enzymes. Compared to enzymes of aerobic bacteria, those of anaerobic origin mainly show low molecular mass of about 25 000 daltons. Some of the enzymes may have useful applications in the starch industry because of their unusual product pattern, yielding maltotetraose as the main hydrolysis product. (orig.).

DEVELOPMENT OF IMPROVED ANAEROBIC GROWTH OF BACILLUS MOJAVENSIS STRAIN JF-2 FOR THE PURPOSE OF IMPROVED ANAEROBIC BIOSURFACTANT PRODUCTION FOR ENHANCED OIL RECOVERY

Energy Technology Data Exchange (ETDEWEB)

M.J. McInerney; M. Folmsbee; D. Nagle

2004-05-31

Our work focuses on the use of microorganisms to recover petroleum hydrocarbons that remain entrapped after current recovery technologies reach their economic limit. Capillary forces between the hydrocarbon and aqueous phases are largely responsible for trapping the hydrocarbons in the pores of the rock and large reductions in the interfacial tension between the hydrocarbon and aqueous phases are needed for hydrocarbon mobilization (1-3, 10, 11). Microorganisms produce a variety of biosurfactants (4), several of which generate the ultra low interfacial tensions needed for hydrocarbon mobilization (4, 5, 8). In particular, the lipopeptide biosurfactant produced by Bacillus mojavensis strain JF-2 reduces the interfacial tension between hydrocarbon and aqueous phases to very low levels (<0.016 mN/m) (8) (9). B. mojavensis JF-2 grows under the environmental conditions found in many oil reservoirs, i. e., anaerobic, NaCl concentrations up to 80 g l{sup -1}, and temperatures up to 45 C (6, 7), making it ideally suited for in situ applications. However, anaerobic growth of B. mojavensis JF-2 was inconsistent and difficult to replicate, which limited its use for in situ applications. Our initial studies revealed that enzymatic digests, such as Proteose Peptone, were required for anaerobic growth of Bacillus mojavensis JF-2. Subsequent purification of the growth-enhancing factor in Proteose Peptone resulted in the identification of the growth-enhancing factor as DNA or deoxyribonucleosides. The addition of salmon sperm DNA, herring sperm DNA, E. coli DNA or synthetic DNA (single or double stranded) to Medium E all supported anaerobic growth of JF-2. Further, we found that JF-2 required all four deoxyribonucleosides (deoxyadeonosine, deoxyguanosine, deoxycytidine and thymidine) for growth under strict anaerobic conditions. The requirement for the deoxyribonucleosides did not occur under aerobic growth conditions. DNA was not used as a sole energy source; sucrose was required

Mechanisms Of The Dissolution Inhibition Effect And Their Application To Designing Novel Deep-UV Resists

Science.gov (United States)

Murata, Makoto; Koshiba, Mitsunobu; Harita, Yoshiyuki

1989-08-01

The dissolution inhibition effect and alkaline solubility were investigated for naphthoquinone diazides like 1,2-naphthoquinone diazide (NQD), its 5-sulfonylchloride (NQD-C) and 5-sulfonyloxybenzene (DAM), and for other compounds like sulfonylchlorides, sulfonyl esters, sulfones and a ketone which do not contain a naphthoquinone diazide moiety. As a result, it has turned out that the dissolution inhibition effect does not depend on the specific structure; namely, the naphthoquinone diazide moiety itself, but largely on the alkaline solubility of the compounds added to a novolak resin. An XPS study for the films consisting of a novolak resin and a dissolution inhibitor indicates a formation of an inhibitor-rich protective thin layer on the film surface after immersion of the film in an alkaline developer. In this paper is proposed a new third dissolution inhibition mechanism in addition to the previously reported chemical crosslinking and dipolar interaction; i.e., the alkaline insoluble protective layer inhibits the dissolution of novolak resin at the interface between the film and the developer. A new three-component type deep-UV resist has been also developed as an application of the new mechanism. The resist consists of a novolak resin, 5-diazo Meldrum's acid and a new dissolution inhibitors like phenyltosylate and p-phenylene ditosylate, which successfully improve the residual resist thickness.

ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

Directory of Open Access Journals (Sweden)

RICARDO CAMACHO-MUÑOZ

2014-12-01

Full Text Available This paper dertermined the anaerobic biodegradation of a polymer obtained by extrusion process of native cassava starch, polylactic acid and polycaprolactone. Initially a thermophilic - methanogenic inoculum was prepared from urban solid waste. The gas final methane concentration and medium’s pH reached values of 59,6% and 7,89 respectively. The assay assembly was carried out according ASTM D5511 standard. The biodegradation percent of used materials after 15 day of digestion were: 77,49%, 61,27%, 0,31% for cellulose, sample and polyethylene respectively. Due cellulose showed biodegradation levels higher than 70% it’s deduced that the inoculum conditions were appropriate. A biodegradation level of 61,27%, 59,35% of methane concentration in sample’s evolved gas and a medium’s finale pH of 7,71 in sample’s vessels, reveal the extruded polymer´s capacity to be anaerobically degraded under thermophilic- high solid concentration conditions.

Technetium recovery from high alkaline solution

Energy Technology Data Exchange (ETDEWEB)

Nash, Charles A.

2016-07-12

Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment.

Science.gov (United States)

Tong, Juan; Liu, Jibao; Zheng, Xiang; Zhang, Junya; Ni, Xiaotang; Chen, Meixue; Wei, Yuansong

2016-10-01

The fate of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated during the sludge anaerobic digestion (AD) with microwave-acid (MW-H), microwave (MW) and microwave-H2O2-alkaline (MW-H2O2) pretreatments. Results showed that combined MW pretreatment especially for the MW-H pretreatment could efficiently reduce the ARB concentration, and most ARG concentrations tended to attenuate during the pretreatment. The subsequent AD showed evident removal of the ARB, but most ARGs were enriched after AD. Only the concentration of tetX kept continuous declination during the whole sludge treatment. The total ARGs concentration showed significant correlation with 16S rRNA during the pretreatment and AD. Compared with unpretreated sludge, the AD of MW and MW-H2O2 pretreated sludge presented slightly better ARB and ARGs reduction efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clinical and bacteriological influence of diabetes mellitus on deep neck infection: Systematic review and meta-analysis.

Science.gov (United States)

Hidaka, Hiroshi; Yamaguchi, Takuhiro; Hasegawa, Jun; Yano, Hisakazu; Kakuta, Risako; Ozawa, Daiki; Nomura, Kazuhiro; Katori, Yukio

2015-10-01

Diabetes mellitus has been recognized as the most common systemic disease associated with deep neck infection. We report the first systematic review and meta-analysis of the influence of diabetes on clinical and bacteriological characteristics of deep neck infection. Articles were retrieved from PubMed, EMBASE, and the Japan Medical Abstracts Society database. A critical review of 227 studies identified 20 studies eligible for quantitative synthesis. Diabetes was associated with higher prevalences of multispace spread of infection, complications, and failure to identify pathogenesis, with risk ratios (RRs) of 1.96, 2.42, and 1.29, respectively. Bacteriologically, patients with diabetes showed a higher prevalence of culture identification of Klebsiella pneumoniae (RR, 3.28), and lower prevalences of Streptococcus spp. (RR, 0.57) and anaerobes (RR, 0.54). Deep neck infection with diabetes differs from that without in several clinical aspects. Again, bacteriological differences imply that diabetic infections might be populated by different bacterial flora. © 2014 Wiley Periodicals, Inc.

Ethanol production from bamboo using mild alkaline pre-extraction followed by alkaline hydrogen peroxide pretreatment.

Science.gov (United States)

Yuan, Zhaoyang; Wen, Yangbing; Kapu, Nuwan Sella

2018-01-01

A sequential two-stage pretreatment process comprising alkaline pre-extraction and alkaline hydrogen peroxide pretreatment (AHP) was investigated to convert bamboo carbohydrates into bioethanol. The results showed that mild alkaline pre-extraction using 8% (w/w) sodium hydroxide (NaOH) at 100°C for 180min followed by AHP pretreatment with 4% (w/w) hydrogen peroxide (H 2 O 2 ) was sufficient to generate a substrate that could be efficiently digested with low enzyme loadings. Moreover, alkali pre-extraction enabled the use of lower H 2 O 2 charges in AHP treatment. Two-stage pretreatment followed by enzymatic hydrolysis with only 9FPU/g cellulose led to the recovery of 87% of the original sugars in the raw feedstock. The use of the pentose-hexose fermenting Saccharomyces cerevisiae SR8u strain enabled the utilization of 95.7% sugars in the hydrolysate to reach 4.6%w/v ethanol titer. The overall process also enabled the recovery of 62.9% lignin and 93.8% silica at high levels of purity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sequential batch anaerobic composting (SEBAC sup TM ) of solid wastes

Energy Technology Data Exchange (ETDEWEB)

Chynoweth, D.P.; O' Keefe, D.M.; Barkdoll, A.W.; Owens, J.M. (Department of Agricultural Engineering, University of Florida, Gainesville, Florida (US)); Legrand, R. (Radian Corporation, Austin, Texas (US))

1992-01-01

Anaerobic high-solids digestion (anaerobic composting) is an attractive option for treatment of organic wastes. The main advantages of anaerobic composting are the lack of aeration requirements and production of methane. An anaerobic composting design, sequential batch anaerobic composting (SEBAC{sup TM}), has been developed and demonstrated at the pilot scale which has proven to be stable and effective for treatment of the non-yeard waste and yard waste organic fractions of municipal solid waste (MSW). The design employs leachate recycle for wetting, inoculation, and removal of volatile organic acids during startup. Performance is similar to that of other designs requiring heavy solids inoculation and mixing and which do not have a mechanism for volatile organic acid removal during imbalance. (au) (12 refs.).

Peritoneal dialysis peritonitis by anaerobic pathogens: a retrospective case series

Science.gov (United States)

2013-01-01

Background Bacterial infections account for most peritoneal dialysis (PD)-associated peritonitis episodes. However, anaerobic PD peritonitis is extremely rare and intuitively associated with intra-abdominal lesions. In this study, we examined the clinical characteristics of PD patients who developed anaerobic peritonitis. Methods We retrospectively identified all anaerobic PD peritonitis episodes from a prospectively collected PD registry at a single center between 1990 and 2010. Only patients receiving more than 3 months of PD were enrolled. We analyzed clinical features as well as outcomes of anaerobic PD peritonitis patients. Results Among 6 patients, 10 episodes of PD-associated peritonitis were caused by anaerobic pathogens (1.59% of all peritonitis episodes during study the period), in which the cultures from 5 episodes had mixed growth. Bacteroides fragilis was the most common species identified (4 isolates). Only 3 episodes were associated with gastrointestinal lesions, and 4 episodes were related to a break in sterility during exchange procedures. All anaerobic pathogens were susceptible to clindamycin and metronidazole, but penicillin resistance was noted in 4 isolates. Ampicillin/sulbactam resistance was found in 2 isolates. In 5 episodes, a primary response was achieved using the first-generation cephalosporin and ceftazidime or aminoglycoside. In 3 episodes, the first-generation cephalosporin was replaced with aminoglycosides. Tenckhoff catheter removal was necessary in 2 episodes. Only one episode ended with mortality (due to a perforated bowel). Conclusion Anaerobic PD-associated peritonitis might be predominantly caused by contamination, rather than intra-abdominal events. Half of anaerobic PD-associated peritonitis episodes had polymicrobial growth. The overall outcome of anaerobic peritonitis is fair, with a high catheter survival rate. PMID:23705895

Anaerobic bioleaching of metals from waste activated sludge

KAUST Repository

Meulepas, Roel J W

2015-05-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342μgg-1 of copper, 487μgg-1 of lead, 793μgg-1 of zinc, 27μgg-1 of nickel and 2.3μgg-1 of cadmium. During the anaerobic acidification of 3gdry weightL-1 waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.

Characteristics of residues from thermally treated anaerobic sludges

International Nuclear Information System (INIS)

Friedman, A.A.; Smith, J.E.; De Santis, J.; Ptak, T.; Ganley, R.C.

1988-01-01

Sludge management and disposal are probably the most difficult and expensive operations involved in wastewater treatment today. To minimize final disposal costs many waste treatment facilities practice some form of anaerobic digestion and dewatering to reduce the volume and offensiveness of their by-product sludges. One potential alternative for reducing sludge volumes consists of high temperature, partial oxidation of these previously digested sludges (PDS) and subsequent anaerobic biological conversion of resulting soluble organics to methane. This paper describes solids destruction, residue characteristics and biodegradability factors that should be considered in the design of liquid thermal treatment processes for the management of anaerobic sludges. To date only very limited information is available concerning the suitability of thermally treated PDS to serve as a substrate for the generation of methane. The primary objective of this research was to determine the feasibility of producing methane efficiently from the residual VSS in anaerobically digested sludges. Secondary goals were to establish the ''best'' conditions for thermal treatment for solubilizing PDS, to observe the effect of the soluble products on methanogenesis and to evaluate process sidestreams for dewaterability and anaerobic biodegradability

Production of alkaline proteases by alkalophilic Bacillus subtilis ...

African Journals Online (AJOL)

Tuoyo Aghomotsegin

2016-11-23

Nov 23, 2016 ... Key words: Production, alkaline protease, Bacillus subtilis, animal wastes, enzyme activity. ... Generally, alkaline proteases are produced using submerged fermentation .... biopolymer concentrations were reported to have an influence ... adding nitrogenous compounds stimulate microorganism growth and ...

Low alkaline cement used in the construction of a gallery in the Horonobe Underground Research Laboratory

International Nuclear Information System (INIS)

Nakayama, Masashi; Sato, Haruo; Sugita, Yutaka; Ito, Seiji; Minamide, Masashi; Kitagawa, Yoshito

2011-01-01

In Japan, any high level radioactive waste (HLW) pos is to be constructed at over 300 m depth below surface. Tunnel support is used for safety during the construction and operation, and shotcrete and concrete lining are used as the tunnel support. Concrete is a composite material comprised of aggregate, cement and various admixtures. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. Japan Atomic Energy Agency (JAEA) has developed a low alkaline cement, named as HFSC (Highly Flyash Contained Silicafume Cement), containing over 60wt% of silica-fume (SF) and fly-ash (FA). HFSC was used experimentally as the shotcrete material in construction of part of the 140m deep gallery in the Horonobe Underground Research Laboratory (URL). The objective of this experiment was to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. HFSC used in this experiment is composed of 40wt% OPC (Ordinary Portland Cement), 20wt% SF, and 40 wt% FA. This composition was determined based on mechanical testing of various mixes of the above components. Because of the low OPC content, the strength of HFSC tends to be lower than that of OPC. The total length of tunnel using HFSC shotcrete is about 73 m and about 500 m 3 of HESC was used. The workability of HESC shotcrete was confirmed in this experimental construction. (author)

Potential Osteoporosis Recovery by Deep Sea Water through Bone Regeneration in SAMP8 Mice

Directory of Open Access Journals (Sweden)

Hen-Yu Liu

2013-01-01

Full Text Available The aim of this study is to examine the therapeutic potential of deep sea water (DSW on osteoporosis. Previously, we have established the ovariectomized senescence-accelerated mice (OVX-SAMP8 and demonstrated strong recovery of osteoporosis by stem cell and platelet-rich plasma (PRP. Deep sea water at hardness (HD 1000 showed significant increase in proliferation of osteoblastic cell (MC3T3 by MTT assay. For in vivo animal study, bone mineral density (BMD was strongly enhanced followed by the significantly increased trabecular numbers through micro-CT examination after a 4-month deep sea water treatment, and biochemistry analysis showed that serum alkaline phosphatase (ALP activity was decreased. For stage-specific osteogenesis, bone marrow-derived stromal cells (BMSCs were harvested and examined. Deep sea water-treated BMSCs showed stronger osteogenic differentiation such as BMP2, RUNX2, OPN, and OCN, and enhanced colony forming abilities, compared to the control group. Interestingly, most untreated OVX-SAMP8 mice died around 10 months; however, approximately 57% of DSW-treated groups lived up to 16.6 months, a life expectancy similar to the previously reported life expectancy for SAMR1 24 months. The results demonstrated the regenerative potentials of deep sea water on osteogenesis, showing that deep sea water could potentially be applied in osteoporosis therapy as a complementary and alternative medicine (CAM.

Safety of an alkalinizing buffer designed for inhaled medications in humans.

Science.gov (United States)

Davis, Michael D; Walsh, Brian K; Dwyer, Scott T; Combs, Casey; Vehse, Nico; Paget-Brown, Alix; Pajewski, Thomas; Hunt, John F

2013-07-01

Airway acidification plays a role in disorders of the pulmonary tract. We hypothesized that the inhalation of alkalinized glycine buffer would measurably alkalinize the airways without compromising lung function or causing adverse events. We evaluated the safety of an inhaled alkaline glycine buffer in both healthy subjects and in subjects with stable obstructive airway disease. This work includes 2 open-label safety studies. The healthy controls were part of a phase 1 safety study of multiple inhalations of low-dose alkaline glycine buffer; nebulized saline was used as a comparator in 8 of the healthy controls. Subsequently, a phase 2 study in subjects with stable obstructive airway disease was completed using a single nebulized higher-dose strategy of the alkaline inhalation. We studied 20 non-smoking adults (10 healthy controls and 10 subjects with obstructive airway disease), both at baseline and after inhalation of alkaline buffer. We used spirometry and vital signs as markers of clinical safety. We used changes in fraction of exhaled nitric oxide (NO) and exhaled breath condensate (EBC) pH as surrogate markers of airway pH modification. Alkaline glycine inhalation was tolerated by all subjects in both studies, with no adverse effects on spirometric parameters or vital signs. Airway alkalinization was confirmed by a median increase in EBC pH of 0.235 pH units (IQR 0.56-0.03, P = .03) in subjects after inhalation of the higher-dose alkaline buffer (2.5 mL of 100 mmol/L glycine). Alkalinization of airway lining fluid is accomplished with inhalation of alkaline glycine buffer and causes no adverse effects on pulmonary function or vital signs.

Alkalinity and trophic state regulate aquatic plant distribution in Danish lakes

DEFF Research Database (Denmark)

Vestergaard, Ole Skafte; Sand-Jensen, Kaj

2000-01-01

distinct differences in the distribution of species and growth forms among the lakes. The lakes separated into five groups of characteristic species compositions. Alkalinity was the main factor responsible for the species distribution. Lakes of high alkalinity were dominated by vascular plants...... of the elodeid growth form, lakes of intermediate alkalinity contained a variety of elodeids and vascular plants of the isoetid growth form, while lakes of low alkalinity and low pH had several isoetids and bryophytes, but very few elodeids. Alkalinity is a close descriptor of the bicarbonate concentration...

Modelling of Two-Stage Anaerobic Treating Wastewater from a Molasses-Based Ethanol Distillery with the IWA Anaerobic Digestion Model No.1

Directory of Open Access Journals (Sweden)

Kittikhun Taruyanon

2010-03-01

Full Text Available This paper presents the application of ADM1 model to simulate the dynamic behaviour of a two-stage anaerobic treatment process treating the wastewater generated from the ethanol distillery process. The laboratory-scale process comprised an anaerobic continuous stirred tank reactor (CSTR and an upflow anaerobic sludge blanket (UASB connecting in series, was used to treat wastewater from the ethanol distillery process. The CSTR and UASB hydraulic retention times (HRT were 12 and 70 hours, respectively. The model was developed based on ADM1 basic structure and implemented with the simulation software AQUASIM. The simulated results were compared with measured data obtained from using the laboratory-scale two-stage anaerobic treatment process to treat wastewater. The sensitivity analysis identified maximum specific uptake rate (km and half-saturation constant (Ks of acetate degrader and sulfate reducing bacteria as the kinetic parameters which highly affected the process behaviour, which were further estimated. The study concluded that the model could predict the dynamic behaviour of a two-stage anaerobic treatment process treating the ethanol distillery process wastewater with varying strength of influents with reasonable accuracy.

Modelling non-redox enzymes: Anaerobic and aerobic acetylene ...

Indian Academy of Sciences (India)

Administrator

Modelling non-redox enzymes: Anaerobic and aerobic acetylene hydratase. SABYASACHI SARKAR. Department of Chemistry, Indian Institute of Technology, Kanpur 208 016,. India. Acetaldehyde is the first metabolite produced during acetylene degradation by bacteria either aerobically or anaerobically. Conversion of ...

Methane fermentation process as anaerobic digestion of biomass ...

African Journals Online (AJOL)

Anaerobic decomposition of organic compounds is conducted in close cooperation of specialized bacteria of different types, including mostly hydrolyzing, digestive, acetogenic, homoacetogenic, sulfate-reducing (VI) and methanogenic bacteria. A great interest in the anaerobic digestion process results mainly from its ...

Production of alkaline proteases by alkalophilic Bacillus subtilis ...

African Journals Online (AJOL)

Tuoyo Aghomotsegin

2016-11-23

Nov 23, 2016 ... A new strain of Bacillus sp. was isolated from alkaline soil, which was able to produce extracellular alkaline ... rice and dates (Khosravi-Darani et al., 2008), protein by- products from lather ..... Pigeon pea waste as a novel ...

Induced and catalysed mineral precipitation in the deep biosphere

Science.gov (United States)

Meister, Patrick

2017-04-01

Authigenic and early diagenetic minerals provide archives of past (bio)geochemical processes. In particular, isotopic signatures preserved in the diagenetic phases have been shown to document drastic changes of subsurface microbial activity (the deep biosphere) over geological time periods (Contreras et al., 2013; Meister, 2015). Geochemical and isotopic signatures in authigenic minerals may also document surface conditions and past climate. Nevertheless, such use of authigenic mineral phases as (bio)geochemical archives is often hampered by the insufficient understanding of mineral precipitation mechanisms. Accordingly the time, place and rate of mineral precipitation are often not well constrained. Also, element partitioning and isotopic fractionation may be modified as a result of the precipitation mechanism. Early diagenetic dolomite and quartz from drilled sequences in the Pacific were compared with adjacent porewater compositions and isotope signatures to gain fundamental insight into the factors controlling mineral precipitation. The formation of dolomite in carbonate-free organic carbon-rich ocean margin sediments (e.g. Peru Margin; Ocean Drilling Program, ODP, Site 1229; Meister et al., 2007) relies on the alkalinity-increase driven by anaerobic oxidation of methane and, perhaps, by alteration of clay minerals. In contrast, quartz is often significantly oversaturated in marine porewaters as the dissolved silica concentration is buffered by more soluble opal-A. For example, quartz does not form throughout a 400 metre thick sedimentary sequence in the Eastern Equatorial Pacific (ODP Site 1226; Meister et al., 2014) because it is kinetically inhibited. This behaviour can be explained by Ostwald's step rule, which suggests that the metastable phase forms faster. However, hard-lithified quartz readily forms where silica concentration drops sharply below opal-saturation. This violation of Ostwald's step rule must be driven by an auxiliary process, such as the

Using contaminated plants involved in phytoremediation for anaerobic digestion.

Science.gov (United States)

Cao, Zewei; Wang, Shengxiao; Wang, Ting; Chang, Zhizhou; Shen, Zhenguo; Chen, Yahua

2015-01-01

This study investigated the anaerobic digestion capability of five plants and the effects of copper (Cu) and S,S'-ethylenediaminedisuccinic acid (EDDS, a chelator widely used in chelant-assisted phytoremediation) on biogas production to determine a feasible disposal method for plants used in remediation. The results showed that in addition to Phytolacca americana L., plants such as Zea mays L., Brassica napus L., Elsholtzia splendens Nakai ex F. Maekawa, and Oenothera biennis L. performed well in biogas production. Among these, O. biennis required the shortest period to finish anaerobic digestion. Compared to normal plants with low Cu content, the plants used in remediation with increased Cu levels (100 mg kg(-1)) not only promoted anaerobic digestion and required a shorter anaerobic digestion time, but also increased the methane content in biogas. When the Cu content in plants increased to 500, 1000, and 5000 mg kg(-1), the cumulative biogas production decreased by 12.3%, 14.6%, and 41.2%, respectively. Studies also found that EDDS conspicuously restrained biogas production from anaerobic digestion. The results suggest that anaerobic digestion has great potential for the disposal of contaminated plants and may provide a solution for the resource utilization of plants used in remediation.

Isotherms of ion exchange on titanates of alkaline metals

International Nuclear Information System (INIS)

Fillina, L.P.; Belinskaya, F.A.

1986-01-01

Present article is devoted to isotherms of ion exchange on titanates of alkaline metals. Therefore, finely dispersed hydrated titanates of alkaline metals (lithium, sodium, potassium) with ion exchange properties are obtained by means of alkaline hydrolysis of titanium chloride at high ph rates. Sorption of cations from salts solution of Li 2 SO 4 , NaNO 3 , Ca(NO 3 ) 2 , AgNO 3 by titanates is studied.

Oxygen Effects in Anaerobic Digestion

Directory of Open Access Journals (Sweden)

Deshai Botheju

2009-10-01

Full Text Available Interaction of free oxygen in bio-gasification is a sparsely studied area, apart from the common argument of oxygen being toxic and inhibitory for anaerobic micro-cultures. Some studies have, however, revealed increased solubilisation of organic matter in the presence of some free oxygen in anaerobic digestion. This article analyses these counterbalancing phenomena with a mathematical modelling approach using the widely accepted biochemical model ADM 1. Aerobic oxidation of soluble carbon and inhibition of obligatory anaerobic organisms are modelled using standard saturation type kinetics. Biomass dependent first order hydrolysis kinetics is used to relate the increased hydrolysis rate with oxygen induced increase in biomass growth. The amended model, ADM 1-Ox (oxygen, has 25 state variables and 22 biochemical processes, presented in matrix form. The computer aided simulation tool AQUASIM 2.1 is used to simulate the developed model. Simulation predictions are evaluated against experimental data obtained using a laboratory batch test array comprising miniature anaerobic bio-reactors of 100 ml total volume each, operated under different initial air headspaces giving rise to the different oxygen loading conditions. The reactors were initially fed with a glucose solution and incubated at 35 Celsius, for 563 hours. Under the oxygen load conditions of 22, 44 and 88 mg/L, the ADM1-Ox model simulations predicted the experimental methane potentials quite adequately. Both the experimental data and the simulations suggest a linear reduction of methane potential with respect to the increase in oxygen load within this range.

Evaluation and characterization during the anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor.

Science.gov (United States)

Xiao, Xiaolan; Huang, Zhenxing; Ruan, Wenquan; Yan, Lintao; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing

2015-10-01

The anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor (AnMBR) was investigated at two different operational modes, including no sludge discharge and daily sludge discharge of 20 L. The AnMBR provided excellent and reliable permeate quality with high COD removal efficiencies over 99%. The obvious accumulations of long chain fatty acids (LCFAs) and Ca(2+) were found in the anaerobic digester by precipitation and agglomeration. Though the physicochemical process contributed to attenuating the free LCFAs toxicity on anaerobic digestion, the digestion efficiency was partly influenced for the low bioavailability of those precipitates. Moreover, higher organic loading rate (OLR) of 5.8 kg COD/(m(3) d) and digestion efficiency of 78% were achieved as the AnMBR was stably operated with sludge discharge, where the membrane fouling propensity was also alleviated, indicating the crucial significance of SRT control on the treatment of high-strength kitchen waste slurry via AnMBRs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization and Optimization of Dual Anaerobic/Aerobic Biofilm Process

National Research Council Canada - National Science Library

Togna, A

1997-01-01

The purpose of this Phase I STTR effort was to develop and characterize a dual anaerobic/aerobic biofilm process that promotes anaerobic reductive dehalogenation and aerobic cometabolic biodegradation...

A bio-electrochemical system for removing inhibitors of anaerobic digestion processes from anaerobic reactors

DEFF Research Database (Denmark)

2014-01-01

Inhibition of anaerobic digestion process by high level of ammonia (NH4 +/I\\IH3) is the most serious problem existing in biogas plants. No viable/applicable method to overcome this problem has been found up to now. This invention proposes an innovative submersible bio-electrochemical membrane...... reactor to recover ammonia from anaerobic digestion reactor, and thereby alleviate or counteract ammonia inhibition and enhance the conversion of ammonia-rich wastes to biogas. The invention may further reduce overall cost, giving synergistic advantages for both ammonia recycling and biogas plants...... by recovering acid (e.g., H2SO4, HCI), that can be used to treat the recovered ammonia....

Anaerobic fitness assessment in taekwondo athletes. A new perspective

Directory of Open Access Journals (Sweden)

Fernando Rocha

2016-10-01

Full Text Available We intended to determine the concurrent validity of a taekwondo specific anaerobic test (TSAT to assess anaerobic fitness in taekwondo athletes. Seventeen elite male subjects (17.59 ± 4.34 years of age; 1.72 m ± .07 m in height; 61.3 kg ± 8.7 kg in weight and 15.6% ± 8.5% in body fat performed a TSAT, which consisted of kicking a punching bag for 30 seconds. The standard test was the Wingate Anaerobic Test. Two trials were made for both tests and the agreement between both was tested. The variables analysed and compared were: peak power; relative peak power; mean anaerobic power; relative mean anaerobic power; fatigue index and anaerobic capacity. The number of kicks performed in the TSAT protocol and the maximum height of the counter movement jump (CMJ were also registered. Trial I and II had significant ICC results in all variables (P = .000 ranged between 0.56 and 0.97. Both protocols were significantly correlated (r = 0.55 to 0.88; P = .000 to .05. CMJ strongly correlated with the number of techniques (r=0.59; P = .013 and the mean power (r = 0.56; P = .019 of the TSAT. The variables between the two methods correlate and are consistent, except for the anaerobic capacity that although correlated, is not consistent with constant bias, P = 0.001; CI]-705.1;-370.2[. TSAT has a level of agreement with the Wingate, and assigns specificity in the evaluation of these variables.

Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

Science.gov (United States)

Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)

2000-01-01

The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

Assessment of deep electrical conductivity features of Northern Victoria Land (Antarctica under other geophysical constraints

Directory of Open Access Journals (Sweden)

A. Caneva

2000-06-01

Full Text Available The lithospheric and crustal structure of the Victoria Land continental block (Antarctica has been studied by geological and geophysical surveys. Among them magnetovariational investigations (MV have been addressed to highlight the deep electrical conductivity patterns which contribute to the understanding of continental rifting and tectonic setting of the region. The hypothetical event map for H linearly polarized perpendicular to the coast indicates a possible broad coast parallel conductivity anomaly zone. Despite the coast effect, this feature could be related to the deep upper mantle thermal anomaly leading to Cenozoic uplift of the Transantarctic Mountains rift flank. However, both the hypothetic event map polarized parallel to the coast and the induction arrows suggest that the area of enhanced conductivity may be confined to the Deep Freeze Range crustal block along the western flank of the Mesozoic Rennick Graben. We also discuss the possible association between increased conductivity over the Southern Cross block and extensive Cenozoic alkaline plutonism.

Isolation of obligate and facultative anaerobic bacteria from feline subcutaneous abscesses.

Science.gov (United States)

Hoshuyama, S; Kanoe, M; Amimoto, A

1996-03-01

A total of 113 specimens collected from purulent skin lesions of household cats was examined bacteriologically. Ninety seven isolates obtained from 74 specimens (65.5%). Of these, 11 specimens (9.7%) contained obligate anaerobes only, 18 specimens (15.9%) yielded both obligate and facultative anaerobes. In the obligate anaerobes detected, genus Fusobacterium was the most frequently observed and F. nucleatum was most common species. Pasteurella multocida was the facultative anaerobe which was most frequently detected.

The deep-subsurface sulfate reducer Desulfotomaculum kuznetsovii employs two methanol-degrading pathways.

Science.gov (United States)

Sousa, Diana Z; Visser, Michael; van Gelder, Antonie H; Boeren, Sjef; Pieterse, Mervin M; Pinkse, Martijn W H; Verhaert, Peter D E M; Vogt, Carsten; Franke, Steffi; Kümmel, Steffen; Stams, Alfons J M

2018-01-16

Methanol is generally metabolized through a pathway initiated by a cobalamine-containing methanol methyltransferase by anaerobic methylotrophs (such as methanogens and acetogens), or through oxidation to formaldehyde using a methanol dehydrogenase by aerobes. Methanol is an important substrate in deep-subsurface environments, where thermophilic sulfate-reducing bacteria of the genus Desulfotomaculum have key roles. Here, we study the methanol metabolism of Desulfotomaculum kuznetsovii strain 17 T , isolated from a 3000-m deep geothermal water reservoir. We use proteomics to analyze cells grown with methanol and sulfate in the presence and absence of cobalt and vitamin B12. The results indicate the presence of two methanol-degrading pathways in D. kuznetsovii, a cobalt-dependent methanol methyltransferase and a cobalt-independent methanol dehydrogenase, which is further confirmed by stable isotope fractionation. This is the first report of a microorganism utilizing two distinct methanol conversion pathways. We hypothesize that this gives D. kuznetsovii a competitive advantage in its natural environment.

Anaerobic bacteria in wastewater treatment plant.

Science.gov (United States)

Cyprowski, Marcin; Stobnicka-Kupiec, Agata; Ławniczek-Wałczyk, Anna; Bakal-Kijek, Aleksandra; Gołofit-Szymczak, Małgorzata; Górny, Rafał L

2018-03-28

The objective of this study was to assess exposure to anaerobic bacteria released into air from sewage and sludge at workplaces from a wastewater treatment plant (WWTP). Samples of both sewage and sludge were collected at six sampling points and bioaerosol samples were additionally collected (with the use of a 6-stage Andersen impactor) at ten workplaces covering different stages of the technological process. Qualitative identification of all isolated strains was performed using the biochemical API 20A test. Additionally, the determination of Clostridium pathogens was carried out using 16S rRNA gene sequence analysis. The average concentration of anaerobic bacteria in the sewage samples was 5.49 × 10 4 CFU/mL (GSD = 85.4) and in sludge-1.42 × 10 6 CFU/g (GSD = 5.1). In turn, the average airborne bacterial concentration was at the level of 50 CFU/m 3 (GSD = 5.83) and the highest bacterial contamination (4.06 × 10 3  CFU/m 3 ) was found in winter at the bar screens. In total, 16 bacterial species were determined, from which the predominant strains belonged to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera. The analysis revealed that mechanical treatment processes were responsible for a substantial emission of anaerobic bacteria into the air. In both the sewage and air samples, Clostridium perfringens pathogen was identified. Anaerobic bacteria were widely present both in the sewage and in the air at workplaces from the WWTP, especially when the technological process was performed in closed spaces. Anaerobic bacteria formed small aggregates with both wastewater droplets and dust particles of sewage sludge origin and as such may be responsible for adverse health outcomes in exposed workers.

The aerobic activity of metronidazole against anaerobic bacteria.

Science.gov (United States)

Dione, Niokhor; Khelaifia, Saber; Lagier, Jean-Christophe; Raoult, Didier

2015-05-01

Recently, the aerobic growth of strictly anaerobic bacteria was demonstrated using antioxidants. Metronidazole is frequently used to treat infections caused by anaerobic bacteria; however, to date its antibacterial activity was only tested in anaerobic conditions. Here we aerobically tested using antioxidants the in vitro activities of metronidazole, gentamicin, doxycycline and imipenem against 10 common anaerobic and aerobic bacteria. In vitro susceptibility testing was performed by the disk diffusion method, and minimum inhibitory concentrations (MICs) were determined by Etest. Aerobic culture of the bacteria was performed at 37°C using Schaedler agar medium supplemented with 1mg/mL ascorbic acid and 0.1mg/mL glutathione; the pH was adjusted to 7.2 by 10M KOH. Growth of anaerobic bacteria cultured aerobically using antioxidants was inhibited by metronidazole after 72h of incubation at 37°C, with a mean inhibition diameter of 37.76mm and an MIC of 1μg/mL; however, strains remained non-sensitive to gentamicin. No growth inhibition of aerobic bacteria was observed after 24h of incubation at 37°C with metronidazole; however, inhibition was observed with doxycycline and imipenem used as controls. These results indicate that bacterial sensitivity to metronidazole is not related to the oxygen tension but is a result of the sensitivity of the micro-organism. In future, both culture and antibiotic susceptibility testing of strictly anaerobic bacteria will be performed in an aerobic atmosphere using antioxidants in clinical microbiology laboratories. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Hydroponic system for the treatment of anaerobic liquid.

Science.gov (United States)

Krishnasamy, K; Nair, J; Bäuml, B

2012-01-01

The effluent from anaerobic digestion process has high concentrations of nutrients, particularly nitrogen, essential for plant growth but is not suitable for direct disposal or application due to high chemical oxygen demand (COD), low dissolved oxygen (DO), odour issues and is potentially phytotoxic. This research explored the optimum conditions of anaerobic effluent for application and dilutions of the effluent required to obtain better plant growth. A small-scale hydroponic system was constructed in a glasshouse to test different concentrations of anaerobic effluent against a commercial hydroponic medium as the control for the growth of silverbeet. It was found that the survival of silverbeet was negatively affected at 50% concentration due to low DO and NH(4) toxicity. The concentration of 20% anaerobic liquid was found to be the most efficient with highest foliage yield and plant growth. The hydroponic system with 20% concentrated effluent had better utilisation of nutrients for plant growth and a COD reduction of 95% was achieved during the 50-day growth period. This preliminary evaluation revealed that the growth and development of silverbeet was significantly lower in anaerobic effluent compared with a commercial hydroponic plant growth solution. The nutrient quality of anaerobic effluent could be highly variable with the process and the waste material used and dilution may depend on the nutrient content of the effluent. It is recommended that, a pre-treatment of the effluent to increase DO and reduce ammonium content is required before plant application, and simple dilution by itself is not suitable for optimum plant growth in a hydroponic system.

Anaerobic catabolism of aromatic compounds: a genetic and genomic view.

Science.gov (United States)

Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F; Valderrama, J Andrés; Barragán, María J L; García, José Luis; Díaz, Eduardo

2009-03-01

Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach.

Microbiological characterization of deep geological compartments

International Nuclear Information System (INIS)

Barsotti, V.; Sergeant, C.; Vesvres, M.H.; Coulon, S.; Joulian, C.; Garrido, F.; Ollivier, B.

2012-01-01

cultivable microorganism could be isolated. - The genetic exploration of these samples revealed a very low biomass and a poor diversity composed mainly of aerobic and facultative anaerobic mesophilic members of the Bacteria domain. This unexpected microbial community also found in many subsurface ecosystems as well as in extreme ones could have partially originated from a paleo-recharge of the Trias aquifer with cold waters coming from the melting of ice formed during the last Pleistocene glaciation. This study is a part of the program TAPPS2000 (Present and past transfers in a sedimentary aquifer - aquitard system: a 2000 meter deep drill-hole in the Mesozoic of the Paris Basin). (authors)

Energy positive domestic wastewater treatment: the roles of anaerobic and phototrophic technologies.

Science.gov (United States)

Shoener, B D; Bradley, I M; Cusick, R D; Guest, J S

2014-05-01

The negative energy balance of wastewater treatment could be reversed if anaerobic technologies were implemented for organic carbon oxidation and phototrophic technologies were utilized for nutrient recovery. To characterize the potential for energy positive wastewater treatment by anaerobic and phototrophic biotechnologies we performed a comprehensive literature review and analysis, focusing on energy production (as kJ per capita per day and as kJ m(-3) of wastewater treated), energy consumption, and treatment efficacy. Anaerobic technologies included in this review were the anaerobic baffled reactor (ABR), anaerobic membrane bioreactor (AnMBR), anaerobic fluidized bed reactor (AFB), upflow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), microbial electrolysis cell (MEC), and microbial fuel cell (MFC). Phototrophic technologies included were the high rate algal pond (HRAP), photobioreactor (PBR), stirred tank reactor, waste stabilization pond (WSP), and algal turf scrubber (ATS). Average energy recovery efficiencies for anaerobic technologies ranged from 1.6% (MFC) to 47.5% (ABR). When including typical percent chemical oxygen demand (COD) removals by each technology, this range would equate to roughly 40-1200 kJ per capita per day or 110-3300 kJ m(-3) of treated wastewater. The average bioenergy feedstock production by phototrophic technologies ranged from 1200-4700 kJ per capita per day or 3400-13 000 kJ m(-3) (exceeding anaerobic technologies and, at times, the energetic content of the influent organic carbon), with usable energy production dependent upon downstream conversion to fuels. Energy consumption analysis showed that energy positive anaerobic wastewater treatment by emerging technologies would require significant reductions of parasitic losses from mechanical mixing and gas sparging. Technology targets and critical barriers for energy-producing technologies are identified, and the role of integrated anaerobic and

Energy positive domestic wastewater treatment: the roles of anaerobic and phototrophic technologies

KAUST Repository

Shoener, B. D.

2014-01-01

The negative energy balance of wastewater treatment could be reversed if anaerobic technologies were implemented for organic carbon oxidation and phototrophic technologies were utilized for nutrient recovery. To characterize the potential for energy positive wastewater treatment by anaerobic and phototrophic biotechnologies we performed a comprehensive literature review and analysis, focusing on energy production (as kJ per capita per day and as kJ m-3 of wastewater treated), energy consumption, and treatment efficacy. Anaerobic technologies included in this review were the anaerobic baffled reactor (ABR), anaerobic membrane bioreactor (AnMBR), anaerobic fluidized bed reactor (AFB), upflow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), microbial electrolysis cell (MEC), and microbial fuel cell (MFC). Phototrophic technologies included were the high rate algal pond (HRAP), photobioreactor (PBR), stirred tank reactor, waste stabilization pond (WSP), and algal turf scrubber (ATS). Average energy recovery efficiencies for anaerobic technologies ranged from 1.6% (MFC) to 47.5% (ABR). When including typical percent chemical oxygen demand (COD) removals by each technology, this range would equate to roughly 40-1200 kJ per capita per day or 110-3300 kJ m-3 of treated wastewater. The average bioenergy feedstock production by phototrophic technologies ranged from 1200-4700 kJ per capita per day or 3400-13000 kJ m-3 (exceeding anaerobic technologies and, at times, the energetic content of the influent organic carbon), with usable energy production dependent upon downstream conversion to fuels. Energy consumption analysis showed that energy positive anaerobic wastewater treatment by emerging technologies would require significant reductions of parasitic losses from mechanical mixing and gas sparging. Technology targets and critical barriers for energy-producing technologies are identified, and the role of integrated anaerobic and phototrophic

Evaluation of some bean lines tolerance to alkaline soil

Directory of Open Access Journals (Sweden)

Abeer A. Radi

2012-01-01

Full Text Available Introduction: In less arid climates, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. The development and identification of salt-tolerant crop cultivars or lines would complement salt management programs to improve the productivity and yields of salt stressed plants.Materials and methods: This work was to study the evaluation of alkalinity tolerance of some bean lines grown under different levels of sodium carbonate (Na2CO3 to select the most alkalinity tolerant lines versus the most-sensitive ones out of 6 lines of the test plants.Results: The symptoms induced by alkalinity included reduction in root, shoot growth, and leaf area which were more severe in some bean lines. Potassium leakage was severely affected by alkalinity in some lines at all tested levels, while in some others a moderate damage was manifested only at the higher levels. The increase in Na2CO3 level was associated with a gradual fall in chlorophyll a and b biosynthesis of all the test bean lines. However, alkalinity at low and moderate levels had a favorable effect on the biosynthesis of carotenoids in all the test bean lines. The increase in Na2CO3 supply had a considerable stimulatory effect on sodium accumulation, while potassium accumulation fluctuated in organs of bean lines.Conclusion: Assiut 1104 out of all the different lines investigated was found to display the lowest sensitivity to alkalinity stress, while Assiut 12/104 was the most sensitive one.

Southwest Pacific deep water carbonate chemistry linked to high southern latitude climate and atmospheric CO2 during the Last Glacial Termination

Science.gov (United States)

Allen, Katherine A.; Sikes, Elisabeth L.; Hönisch, Bärbel; Elmore, Aurora C.; Guilderson, Thomas P.; Rosenthal, Yair; Anderson, Robert F.

2015-08-01

A greater amount of CO2 was stored in the deep sea during glacial periods, likely via greater efficiency of the biologic pump and increased uptake by a more alkaline ocean. Reconstructing past variations in seawater carbonate ion concentration (a major component of alkalinity) enables quantification of the relative roles of different oceanic CO2 storage mechanisms and also places constraints on the timing, magnitude, and location of subsequent deep ocean ventilation. Here, we present a record of deep-water inorganic carbon chemistry since the Last Glacial Maximum (LGM; ∼19-23 ka BP), derived from sediment core RR0503-83 raised from 1627 m in New Zealand's Bay of Plenty. The core site lies within the upper limit of southern-sourced Circumpolar Deep Water (CDW), just below the lower boundary of Antarctic Intermediate Water (AAIW). We reconstruct past changes in bottom water inorganic carbon chemistry from the trace element and stable isotopic composition of calcite shells of the epibenthic foraminifer Cibicidoides wuellerstorfi. A record of ΔCO32-(ΔCO32- = [COCO32-] in situ - [CO32-] saturation) derived from the foraminiferal boron to calcium ratio (B/Ca) provides evidence for greater ice-age storage of respired CO2 and reveals abrupt deglacial shifts in [CO32-] in situ of up to 30 μmol/kg (5 times larger than the difference between average LGM and Holocene values). The rapidity of these changes suggests the influence of changing water mass structure and atmospheric circulation in addition to a decrease in CO2 content of interior waters.

Microbiological and technical aspects of anaerobic waste water purification

International Nuclear Information System (INIS)

Aivasidis, A.

1994-01-01

Anaerobic waste water purification is likely to be another example of how innovations can result from the joint use of biological and technical concepts. No matter how far the optimization of oxygen input with aerobic waste water purification advances it will still be the less a real competitor for anaerobic techniques the more polluted the waste water is. The principle of carrier fixation to avoid their washing out, too, has often been observed in nature with sessile microorganisms. With highly polluted water, anaerobic purification does not only work at no expenditure of energy but it can also make excess energy available for use in other processes. Another important argument for anaerobic methods of waste water purification is probably the clearly reduced production of excess sludge. (orig.) [de

Anaerobic treatment of solid and liquid residues. Papers

International Nuclear Information System (INIS)

Maerkl, H.; Stegmann, R.

1994-01-01

Anaerobic processes are getting increasing attention in the disposal of liquid waste of the food industry and chemical industry and solid organic residues of the municipal sector. The main advantages of anaerobic processes are the favourable energy balance and the comparatively small volume of new biomass produced. There are new satisfactory technical solutions for nearly all problems encountered in practice. A conference on ''Anaerobic treatment of solid and liquid residues'' was held on 2-4 November 1994. The state of the art and new developments were presented in lectures by experts from research and practice. (orig.) [de

Hydroxide Self-Feeding High-Temperature Alkaline Direct Formate Fuel Cells.

Science.gov (United States)

Li, Yinshi; Sun, Xianda; Feng, Ying

2017-05-22

Conventionally, both the thermal degradation of the anion-exchange membrane and the requirement of additional hydroxide for fuel oxidation reaction hinder the development of the high-temperature alkaline direct liquid fuel cells. The present work addresses these two issues by reporting a polybenzimidazole-membrane-based direct formate fuel cell (DFFC). Theoretically, the cell voltage of the high-temperature alkaline DFFC can be as high as 1.45 V at 90 °C. It has been demonstrated that a proof-of-concept alkaline DFFC without adding additional hydroxide yields a peak power density of 20.9 mW cm -2 , an order of magnitude higher than both alkaline direct ethanol fuel cells and alkaline direct methanol fuel cells, mainly because the hydrolysis of formate provides enough OH - ions for formate oxidation reaction. It was also found that this hydroxide self-feeding high-temperature alkaline DFFC shows a stable 100 min constant-current discharge at 90 °C, proving the conceptual feasibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria

International Nuclear Information System (INIS)

Miyahara, Michiko; Miyahara, Makoto

2002-01-01

An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the lethal dose 10% (D 10 ) value of B. cereus at 4 deg C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 deg C. The gamma irradiation of the bacteria without incubation at 4 deg C before irradiation was more effective than that of the bacteria with incubation overnight at 4 deg C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 deg C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. (author)

The Estimation Formation Alkaline In The Proses Desalination MSF

International Nuclear Information System (INIS)

Latiffah, Siti Nurul

2000-01-01

Already to go on estimation phenomena formation alkaline scale of a seawater. In desalination system seawater on MSF to go on scale by a thermal decomposition HCO sub.3- ion and hydrolysis carbonate ion with water on the temperature operation. The varieties alkaline scale in attached on tube surface, while reduced efficiency heat transfer and to raise corrosion attack to structure material is caused all this high cost. Estimation to take please which a sum step by step decomposition ion bicarbonate from then information scale which carbonate and hydroxyl ion. The various scale maximal is alkaline form is a calcium carbonate = 116,5 gram per meter cubic the various sedimentation is alkaline and magnesium hydroxide = 67,57 gram per meter cubic

Microbiology and management of joint and bone infections due to anaerobic bacteria.

Science.gov (United States)

Brook, Itzhak

2008-03-01

To describes the microbiology, diagnosis, and management of septic arthritis and osteomyelitis due to anaerobic bacteria. The predominant anaerobes in arthritis are anaerobic Gram-negative bacilli (AGNB) including the Bacteroides fragilis group, Fusobacterium spp., Peptostreptococcus spp., and Propionibacterium acnes. Infection with P. acnes is associated with a prosthetic joint, previous surgery, and trauma. B. fragilis group is associated with distant infection, Clostridium spp. with trauma, and Fusobacterium spp. with oropharyngeal infection. Most cases of anaerobic arthritis, in contrast to anaerobic osteomyelitis, involved a single isolate, and most cases are secondary to hematogenous spread. The predominant anaerobes in osteomyelitis are Bacteroides, Peptostreptococcus, Fusobacterium, and Clostridium spp. as well as P. acnes. Conditions predisposing to bone infections are vascular disease, bites, contiguous infection, peripheral neuropathy, hematogenous spread, and trauma. Pigmented Prevotella and Porphyromonas spp. are mostly isolated in skull and bite infections, members of the B. fragilis group in hand and feet infections, and Fusobacterium spp. in skull, bite, and hematogenous long bone infections. Many patients with osteomyelitis due to anaerobic bacteria have evidence of an anaerobic infection elsewhere in the body that is the source of the organisms involved in the osteomyelitis. Treatment of arthritis and osteomyelitis involving anaerobic bacteria includes symptomatic therapy, immobilization in some cases, adequate drainage of purulent material, and antibiotic therapy effective against these organisms. Anaerobic bacteria can cause septic arthritis and osteomyelitis. Correct diagnosis and appropriate therapy are important contributor to successful outcome.

Applicability of low alkalinity cement for construction and alteration of bentonite in the cement

International Nuclear Information System (INIS)

Iriya, K.; Fujii, K.; Kubo, H.; Uegaki, Y.

2002-02-01

A concept of radioactive waste repository in which both bentonite and cementitious materials exist in deep cavern as engineered barriers is proposed. It is pointed out that pore water of cement is approximately 12.0 to 13.0 of pH and that it maintains for a long period. Therefore alteration of bentonite and rocks should be studied. Mixing test upon some interaction between modeled cement water and bentonite and rocks have been carried out since 1995 as a part of TRU repository's study. And low alkalinity of cement has been studied as parallel to study on alteration of bentonite. HFSC which has high fly ash content and which shows approximately 10.5 to 11.0 of pH of pore water was developed. Cementitious materials are generally use as a combination with steel, since its tensile strength is low. The corrosion of steel in concrete becomes a big problem in case of decreasing pH of cement. There is little available reference, since low alkalinity cement is quite new and special ordered one. Accelerating test for corrosion in low alkalinity concrete were carried out in order to collect data of corrosion. Although alteration of bentonite by several types of modeled cement water was tested. Long term test by actual cement pore water has not carried out. The alteration in 360 days was investigated. Conclusion obtained in this study is following. Corrosion of steel (re-bar) 1) Re-bar in HFSC with 60% of W/C is significantly corroded. The corrosion rate is bigger than the rate of ordinary used cement. 2) Diffusivity of Cl - ion in HFSC is similar to it in OPC comparing by the same water powder ratio. 3) Corrosion rate of HFSC 30 is similar to OPC60. However corrosion is progressed in HFSC 30 without Cl - ion due to lower alkalinity, but it isn't done in OPC within a certain amount of Cl - ion. Alteration of bentonite and rocks 1) Although no secondary minerals was observed in HFSC, monmorironite is gradually lost by increasing calcite. 2) Secondary minerals were observed in

Schematic Method for Effective Identification of Anaerobes from ...

African Journals Online (AJOL)

They were inoculated into two compounded media; Neomycin Blood Agar (NBA) and Neomycin Plasma Agar (NPA) incubated anaerobically at 37oC for (24-48) hours. Isolated anaerobes were gram-stained and tested using discs impregnated with antibiotics, bile salts and dyes, carbohydrate fermentation and other ...

Moroccan rock phosphate solubilization during a thermo-anaerobic ...

African Journals Online (AJOL)

In order to investigate the presence of thermo-tolerant rock phosphate (RP) solubilizing anaerobic microbes during the fermentation process, we used grassland as sole organic substrate to evaluate the RP solubilization process under anaerobic thermophilic conditions. The result shows a significant decrease of pH from ...

Control of calcium carbonate precipitation in anaerobic reactors

NARCIS (Netherlands)

Langerak, van E.P.A.

1998-01-01

Anaerobic treatment of waste waters with a high calcium content may lead to excessive precipitation of calcium carbonate. So far, no proper methods were available to predict or reduce the extent of precipitation in an anaerobic treatment system. Moreover, it also was not clear to what

Production of alkaline protease by Teredinobacter turnirae cells ...

African Journals Online (AJOL)

The conditions for immobilizing the new alkaline protease-producing bacteria strain Teredinobacter turnirae by entrapment in calcium alginate gel were investigated. The influence of alginate concentration (20, 25 and 30 g/l) and initial cell loading (ICL) on enzyme production were studied. The production of alkaline ...

When can ocean acidification impacts be detected from decadal alkalinity measurements?

Science.gov (United States)

Carter, B. R.; Frölicher, T. L.; Dunne, J. P.; Rodgers, K. B.; Slater, R. D.; Sarmiento, J. L.

2016-04-01

We use a large initial condition suite of simulations (30 runs) with an Earth system model to assess the detectability of biogeochemical impacts of ocean acidification (OA) on the marine alkalinity distribution from decadally repeated hydrographic measurements such as those produced by the Global Ship-Based Hydrographic Investigations Program (GO-SHIP). Detection of these impacts is complicated by alkalinity changes from variability and long-term trends in freshwater and organic matter cycling and ocean circulation. In our ensemble simulation, variability in freshwater cycling generates large changes in alkalinity that obscure the changes of interest and prevent the attribution of observed alkalinity redistribution to OA. These complications from freshwater cycling can be mostly avoided through salinity normalization of alkalinity. With the salinity-normalized alkalinity, modeled OA impacts are broadly detectable in the surface of the subtropical gyres by 2030. Discrepancies between this finding and the finding of an earlier analysis suggest that these estimates are strongly sensitive to the patterns of calcium carbonate export simulated by the model. OA impacts are detectable later in the subpolar and equatorial regions due to slower responses of alkalinity to OA in these regions and greater seasonal equatorial alkalinity variability. OA impacts are detectable later at depth despite lower variability due to smaller rates of change and consistent measurement uncertainty.

Sulfidogenic biotreatment of synthetic acid mine drainage and sulfide oxidation in anaerobic baffled reactor

Energy Technology Data Exchange (ETDEWEB)

Bekmezci, Ozan K.; Ucar, Deniz [Harran University, Environmental Engineering Department, Osmanbey Campus, 63000 Sanliurfa (Turkey); Kaksonen, Anna H. [CSIRO Land and Water, Underwood Avenue, Floreat, WA 6014 (Australia); Sahinkaya, Erkan, E-mail: erkansahinkaya@yahoo.com [Harran University, Environmental Engineering Department, Osmanbey Campus, 63000 Sanliurfa (Turkey)

2011-05-30

The treatment of synthetic acid mine drainage (AMD) water (pH 3.0-6.5) containing sulfate (3.0-3.5 g L{sup -1}) and various metals (Co, Cu, Fe, Mn, Ni, and Zn) was studied in an ethanol-fed sulfate-reducing 4-compartment anaerobic baffled reactor (ABR) at 32 {sup o}C. The reactor was operated for 160 days at different chemical oxygen demand (COD)/sulfate ratios, hydraulic retention times (HRT), pH, and metal concentrations to study the robustness of the process. The last compartment of the reactor was aerated at different rates to study the bio-oxidation of sulfide to elemental sulfur. The highest sulfate reduction efficiency (88%) was obtained with a feed sulfate concentration of 3.5 g L{sup -1}, COD/sulfate mass ratio of 0.737, feed pH of 3.0 and HRT of 2 days without aeration in the 4th compartment. The corresponding COD removal efficiency was about 92%. The alkalinity produced in the sulfidogenic ethanol oxidation neutralized the acidic mine water from pH 3.0-4.5 to pH 7.0-8.0. Effluent soluble and total heavy metal concentrations were substantially reduced with removal efficiencies generally higher than 99%, except for Mn (25-77%). Limited aeration in the 4th compartment of ABR promoted incomplete oxidation of sulfide to elemental sulfur rather than complete oxidation to sulfate. Depending on the aeration rate and HRT, 32-74% of produced sulfide was oxidized to elemental sulfur. This study demonstrates that by optimizing operating conditions, sulfate reduction, metal removal, alkalinity generation, and excess sulfide oxidation can be achieved in a single ABR treating AMD.

Anaerobes as Sources of Bioactive Compounds and Health Promoting Tools.

Science.gov (United States)

Mamo, Gashaw

Aerobic microorganisms have been sources of medicinal agents for several decades and an impressive variety of drugs have been isolated from their cultures, studied and formulated to treat or prevent diseases. On the other hand, anaerobes, which are believed to be the oldest life forms on earth and evolved remarkably diverse physiological functions, have largely been neglected as sources of bioactive compounds. However, results obtained from the limited research done so far show that anaerobes are capable of producing a range of interesting bioactive compounds that can promote human health. In fact, some of these bioactive compounds are found to be novel in their structure and/or mode of action.Anaerobes play health-promoting roles through their bioactive products as well as application of whole cells. The bioactive compounds produced by these microorganisms include antimicrobial agents and substances such as immunomodulators and vitamins. Bacteriocins produced by anaerobes have been in use as preservatives for about 40 years. Because these substances are effective at low concentrations, encounter relatively less resistance from bacteria and are safe to use, there is a growing interest in these antimicrobial agents. Moreover, several antibiotics have been reported from the cultures of anaerobes. Closthioamide and andrimid produced by Clostridium cellulolyticum and Pantoea agglomerans, respectively, are examples of novel antibiotics of anaerobe origin. The discovery of such novel bioactive compounds is expected to encourage further studies which can potentially lead to tapping of the antibiotic production potential of this fascinating group of microorganisms.Anaerobes are widely used in preparation of fermented foods and beverages. During the fermentation processes, these organisms produce a number of bioactive compounds including anticancer, antihypertensive and antioxidant substances. The well-known health promoting effect of fermented food is mostly due to these

[Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

Science.gov (United States)

Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

2013-02-01

Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

Diversity of anaerobic microbes in spacecraft assembly clean rooms.

Science.gov (United States)

Probst, Alexander; Vaishampayan, Parag; Osman, Shariff; Moissl-Eichinger, Christine; Andersen, Gary L; Venkateswaran, Kasthuri

2010-05-01

Although the cultivable and noncultivable microbial diversity of spacecraft assembly clean rooms has been previously documented using conventional and state-of-the-art molecular techniques, the occurrence of obligate anaerobes within these clean rooms is still uncertain. Therefore, anaerobic bacterial communities of three clean-room facilities were analyzed during assembly of the Mars Science Laboratory rover. Anaerobic bacteria were cultured on several media, and DNA was extracted from suitable anaerobic enrichments and examined with conventional 16S rRNA gene clone library, as well as high-density phylogenetic 16S rRNA gene microarray (PhyloChip) technologies. The culture-dependent analyses predominantly showed the presence of clostridial and propionibacterial strains. The 16S rRNA gene sequences retrieved from clone libraries revealed distinct microbial populations associated with each clean-room facility, clustered exclusively within gram-positive organisms. PhyloChip analysis detected a greater microbial diversity, spanning many phyla of bacteria, and provided a deeper insight into the microbial community structure of the clean-room facilities. This study presents an integrated approach for assessing the anaerobic microbial population within clean-room facilities, using both molecular and cultivation-based analyses. The results reveal that highly diverse anaerobic bacterial populations persist in the clean rooms even after the imposition of rigorous maintenance programs and will pose a challenge to planetary protection implementation activities.

High temperature and pressure alkaline electrolysis

DEFF Research Database (Denmark)

Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

2013-01-01

Alkaline electrolyzers have proven to operate reliable for decades on a large scale, but in order to become commercially attractive and compete against conventional technologies for hydrogen production, the production and investment costs have to be reduced. This may occur by increasing the opera......Alkaline electrolyzers have proven to operate reliable for decades on a large scale, but in order to become commercially attractive and compete against conventional technologies for hydrogen production, the production and investment costs have to be reduced. This may occur by increasing...

Reduced anaerobic and aerobic performance in children with primary ciliary dyskinesia.

Science.gov (United States)

Simsek, Senem; Inal-Ince, Deniz; Cakmak, Aslihan; Emiralioglu, Nagehan; Calik-Kutukcu, Ebru; Saglam, Melda; Vardar-Yagli, Naciye; Ozcelik, Hayriye Ugur; Sonbahar-Ulu, Hazal; Bozdemir-Ozel, Cemile; Kiper, Nural; Arikan, Hulya

2018-05-01

Primary ciliary dyskinesia (PCD) restricts lifestyle and increases morbidity. The aim of the study was to investigate anaerobic and aerobic performance in children with PCD and their healthy counterparts. Thirty-one children with PCD and 29 age- and sex-matched healthy subjects were studied. Pulmonary function, hand grip strength (HGS), quadriceps strength (QMS), physical activity, anaerobic capacity (muscle power sprint test), and aerobic performance (modified shuttle walk test (MSWT)) were determined. Pulmonary function, HGS, QMS, mean anaerobic power (MAP), and MSWT distance in PCD were significantly lower than those of healthy subjects (p aerobic performance is impaired in PCD from the early stages. Age determines anaerobic performance. Gender is the determinant of aerobic performance. Whether skeletal muscle characteristics and sex-related changes in body composition affect anaerobic and aerobic capacity in PCD children warrants further study. What is Known: • Exercise performance is determined by anaerobic and aerobic power. • Few studies have shown that PCD patients have lower aerobic performance which is associated with impaired lung function. What is New: • The present research indicated that both anaerobic and aerobic exercise capacity determined using field testing is impaired in PCD from the early stages. • Anaerobic capacity was found to be independently associated with age in PCD. Higher aerobic performance is independently associated with male gender.

Exocellular electron transfer in anaerobic microbial communities.

Science.gov (United States)

Stams, Alfons J M; de Bok, Frank A M; Plugge, Caroline M; van Eekert, Miriam H A; Dolfing, Jan; Schraa, Gosse

2006-03-01

Exocellular electron transfer plays an important role in anaerobic microbial communities that degrade organic matter. Interspecies hydrogen transfer between microorganisms is the driving force for complete biodegradation in methanogenic environments. Many organic compounds are degraded by obligatory syntrophic consortia of proton-reducing acetogenic bacteria and hydrogen-consuming methanogenic archaea. Anaerobic microorganisms that use insoluble electron acceptors for growth, such as iron- and manganese-oxide as well as inert graphite electrodes in microbial fuel cells, also transfer electrons exocellularly. Soluble compounds, like humic substances, quinones, phenazines and riboflavin, can function as exocellular electron mediators enhancing this type of anaerobic respiration. However, direct electron transfer by cell-cell contact is important as well. This review addresses the mechanisms of exocellular electron transfer in anaerobic microbial communities. There are fundamental differences but also similarities between electron transfer to another microorganism or to an insoluble electron acceptor. The physical separation of the electron donor and electron acceptor metabolism allows energy conservation in compounds as methane and hydrogen or as electricity. Furthermore, this separation is essential in the donation or acceptance of electrons in some environmental technological processes, e.g. soil remediation, wastewater purification and corrosion.

Characterization of Human Bone Alkaline Phosphatase in Pichia Pastoris

Science.gov (United States)

Malone, Christine C.; Ciszak, Eva; Karr, Laurel J.

1999-01-01

A soluble form of human bone alkaline phosphatase has been expressed in a recombinant strain of the methylotrophic yeast Pichia pastoris. We constructed a plasmid containing cDNA encoding for human bone alkaline phosphatase, with the hydrophobic carboxyl terminal portion deleted. Alkaline phosphatase was secreted into the medium to a level of 32mg/L when cultured in shake flasks, and enzyme activity was 12U/mg, as measured by a spectrophotometric assay. By conversion to a fermentation system, a yield of 880mg/L has been achieved with an enzyme activity of 968U/mg. By gel electrophoresis analysis, it appears that greater than 50% of the total protein in the fermentation media is alkaline phosphatase. Although purification procedures are not yet completely optimized, they are expected to include filtration, ion exchange and affinity chromatography. Our presentation will focus on the purification and crystallization results up to the time of the conference. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

Contemporaneous alkaline and calc-alkaline series in Central Anatolia (Turkey): Spatio-temporal evolution of a post-collisional Quaternary basaltic volcanism

Science.gov (United States)

Dogan-Kulahci, Gullu Deniz; Temel, Abidin; Gourgaud, Alain; Varol, Elif; Guillou, Hervé; Deniel, Catherine

2018-05-01

This study focuses on spatio-temporal evolution of basaltic volcanism in the Central Anatolian post-collisional Quaternary magmatic province which developed along a NE-SW orientation in Turkey. This magmatic province consists of the stratovolcanoes Erciyes (ES) and Hasandag (HS), and the basaltic volcanic fields of Obruk-Zengen (OZ) and Karapınar (KA). The investigated samples range between basic to intermediate in composition (48-56 wt% SiO2), and exhibit calc-alkaline affinity at ES whereas HS, OZ and KA are alkaline in composition. Based on new Ksbnd Ar ages and major element data, the oldest basaltic rock of ES is 1700 ± 40 ka old and exhibits alkaline character, whereas the youngest basaltic trachyandesite is 12 ± 5 ka old and calc-alkaline in composition. Most ES basaltic rocks are younger than 350 ka. All samples dated from HS are alkaline basalts, ranging from 543 ± 12 ka to 2 ± 7 ka old. With the exception of one basalt, all HS basalts are 100 ka or younger in age. Ksbnd Ar ages range from 797 ± 20 ka to 66 ± 7 ka from OZ. All the basalt samples are alkaline in character and are older than the HS alkaline basalts, with the exception of the youngest samples. The oldest and youngest basaltic samples from KA are 280 ± 7 ka and 163 ± 10 ka, respectively, and are calc-alkaline in character. Based on thermobarometric estimates samples from OZ exhibit the highest cpx-liqidus temperature and pressure. For all centers the calculated crystallization depths are between 11 and 28 km and increase from NE to SW. Multistage crystallization in magma chamber(s) located at different depths can explain this range in pressure. Harker variation diagrams coupled with least-squares mass balance calculations support fractional crystallization for ES and, to lesser extend for HS, OZ and KA. All basaltic volcanic rocks of this study are enriched in large-ion lithophile elements (LILE) and light rare earth elements (LREE). The lack of negative anomalies for high field

Controlling the pH of acid cheese whey in a two-stage anaerobic digester with sodium hydroxide

Energy Technology Data Exchange (ETDEWEB)

Ghaly, A.E.; Ramkumar, D.R.

1999-07-01

Anaerobic digestion of cheese whey offers a two-fold benefit: pollution potential reduction and biogas production. The biogas, as an energy source, could be used to reduce the consumption of traditional fuels in the cheese plant. However, as a result of little or no buffering capacity of whey, the pH of the anaerobic digester drops drastically and the process is inhibited. In this study, the effect of controlling the pH of the second chamber of a two-stage, 150 L anaerobic digester operating on cheese whey on the quality and quantity of biogas and the pollution potential reduction, was investigated using sodium hydroxide. The digester was operated at a temperature of 35 C and a hydraulic retention time of 15 days for three runs (no pH control, pH control with no reseeding, and pH control with reseeding) each lasting 50 days. The results indicated that operating the digester without pH control resulted in a low pH (3.3) which inhibited the methanogenic bacteria. The inhibition was irreversible and the digester did not recover (no methane production) when the pH was restored to 7.0 without reseeding, as the observed increased gas production was a false indication of recovery because the gas was mainly carbon dioxide. The addition of base resulted in a total alkalinity of 12,000 mg L as CaCO{sub 3}. When the system was reseeded and the pH controlled, the total volatile acid concentration was 15,100 mg L (as acetic acid), with acetic (28 %), propionic (21%), butyric (25%), valeric (8%), and caproic (15%) acids as the major constituents. The biogas production was 62.6 L d (0.84m{sup 3}m{sup 3} d) and the methane content was 60.7%. Reductions of 27.3, 30.4 and 23.3 % in the total solids, chemical oxygen demand and total Kjeldahl nitrogen were obtained, respectively. The ammonium nitrogen content increased significantly (140%). (author)

Exposure to polystyrene nanoplastic leads to inhibition of anaerobic digestion system.

Science.gov (United States)

Fu, Shan-Fei; Ding, Jian-Nan; Zhang, Yun; Li, Yi-Fei; Zhu, Rong; Yuan, Xian-Zheng; Zou, Hua

2018-06-01

In this study, impacts of nanoplastic on the pure and mixed anaerobic digestion systems were investigated. Results showed the growth and metabolism of Acetobacteroides hydrogenigenes were partly inhibited by nanoplastic existed in the pure anaerobic digestion system. The anaerobic digestion of sewage sludge was also obviously inhibited by nanoplastic existed in the mixed anaerobic digestion system. Both the methane yield and methane production rate of the mixed anaerobic digestion system showed negative correlation with the nanoplastic concentration. Compared with anaerobic digestion system without nanoplastic, methane yield and maximum daily methane yield at the nanoplastic concentration of 0.2g/L decreased for 14.4% and 40.7%, respectively. In addition, the start-up of mixed anaerobic digestion system was prolonged by addition of nanoplastic. Microbial community structure analysis indicated the microbial community structures were also affected by nanoplastic existed in the system. At the nanoplastic concentration of 0.2g/L, the relative abundances of family Cloacamonaceae, Porphyromonadaceae, Anaerolinaceae and Gracilibacteraceae decreased partly. Conversely, the relative abundances of family Anaerolinaceae, Clostridiaceae, Geobacteraceae, Dethiosulfovibrionaceae and Desulfobulbaceae improved partly. Copyright © 2017 Elsevier B.V. All rights reserved.

Anaerobic Biotransformation and Mobility of Pu and of Pu-EDTA

Energy Technology Data Exchange (ETDEWEB)

Xun, Luying

2009-11-20

The enhanced mobility of radionuclides by co-disposed chelating agent, ethylenediaminetetraacetate (EDTA), is likely to occur only under anaerobic conditions. Our extensive effort to enrich and isolate anaerobic EDTA-degrading bacteria has failed. Others has tried and also failed. To explain the lack of anaerobic biodegradation of EDTA, we proposed that EDTA has to be transported into the cells for metabolism. A failure of uptake may contribute to the lack of EDTA degradation under anaerobic conditions. We demonstrated that an aerobic EDTA-degrading bacterium strain BNC1 uses an ABC-type transporter system to uptake EDTA. The system has a periplasmic binding protein that bind EDTA and then interacts with membrane proteins to transport EDTA into the cell at the expense of ATP. The bind protein EppA binds only free EDTA with a Kd of 25 nM. The low Kd value indicates high affinity. However, the Kd value of Ni-EDTA is 2.4 x 10^(-10) nM, indicating much stronger stability. Since Ni and other trace metals are essential for anaerobic respiration, we conclude that the added EDTA sequestrates all trace metals and making anaerobic respiration impossible. Thus, the data explain the lack of anaerobic enrichment cultures for EDTA degradation. Although we did not obtain an EDTA degrading culture under anaerobic conditions, our finding may promote the use of certain metals that forms more stable metal-EDTA complexes than Pu(III)-EDTA to prevent the enhanced mobility. Further, our data explain why EDTA is the most dominant organic pollutant in surface waters, due to the lack of degradation of certain metal-EDTA complexes.

Anaerobic Biotransformation and Mobility of Pu and of Pu-EDTA

International Nuclear Information System (INIS)

Xun, Luying

2009-01-01

The enhanced mobility of radionuclides by co-disposed chelating agent, ethylenediaminetetraacetate (EDTA), is likely to occur only under anaerobic conditions. Our extensive effort to enrich and isolate anaerobic EDTA-degrading bacteria has failed. Others has tried and also failed. To explain the lack of anaerobic biodegradation of EDTA, we proposed that EDTA has to be transported into the cells for metabolism. A failure of uptake may contribute to the lack of EDTA degradation under anaerobic conditions. We demonstrated that an aerobic EDTA-degrading bacterium strain BNC1 uses an ABC-type transporter system to uptake EDTA. The system has a periplasmic binding protein that bind EDTA and then interacts with membrane proteins to transport EDTA into the cell at the expense of ATP. The bind protein EppA binds only free EDTA with a Kd of 25 nM. The low Kd value indicates high affinity. However, the Kd value of Ni-EDTA is 2.4 x 10 -10 nM, indicating much stronger stability. Since Ni and other trace metals are essential for anaerobic respiration, we conclude that the added EDTA sequestrates all trace metals and making anaerobic respiration impossible. Thus, the data explain the lack of anaerobic enrichment cultures for EDTA degradation. Although we did not obtain an EDTA degrading culture under anaerobic conditions, our finding may promote the use of certain metals that forms more stable metal-EDTA complexes than Pu(III)-EDTA to prevent the enhanced mobility. Further, our data explain why EDTA is the most dominant organic pollutant in surface waters, due to the lack of degradation of certain metal-EDTA complexes.

BIOESTABILIZATION ANAEROBIC SOLID WASTE ORGANIC:QUANTITATIVE ASPECTS

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Valderi Duarte Leite

2015-01-01

Full Text Available It is estimated that in Brazil, the municipal solid waste produced are constituted on average 55% of fermentable organic solid waste and that this quantity can be applied in aerobic or anaerobic stabilization process. Anaerobic digestion is an important alternative for the treatment of different types of potentially fermentable waste, considering providing an alternative source of energy that can be used to replace fossil fuels. To perform the experimental part of this work was constructed and monitored an experimental system consisting of an anaerobic batch reactor, shredding unit of fermentable organic wastes and additional devices. Fermentable organic wastes consisted of leftover fruits and vegetables and were listed in EMPASA (Paraibana Company of Food and Agricultural Services, located in the city of Campina Grande- PB. The residues were collected and transported to the Experimental Station Biological Sewage Treatment (EXTRABES where they were processed and used for substrate preparation. The substrate consisted of a mixture of fermentable organic waste, more anaerobic sewage sludge in the proportion of 80 and 20 % respectively. In the specific case of this study, it was found that 1m3 of substrate concentration of total COD equal to 169 g L-1, considering the reactor efficiency equal to 80 %, the production of CH4 would be approximately 47.25 Nm3 CH4. Therefore, fermentable organic waste, when subjected to anaerobic treatment process produces a quantity of methane gas in addition to the partially biostabilized compound may be applied as a soil conditioning agent.

First Microbial Community Assessment of Borehole Fluids from the Deep Underground Science and Engineering Laboratory (DUSEL)

Science.gov (United States)

Moser, D. P.; Anderson, C.; Bang, S.; Jones, T. L.; Boutt, D.; Kieft, T.; Sherwood Lollar, B.; Murdoch, L. C.; Pfiffner, S. M.; Bruckner, J.; Fisher, J. C.; Newburn, J.; Wheatley, A.; Onstott, T. C.

2010-12-01

Fluid and gas samples were collected from two flowing boreholes at the 4100 (1,250 m) and 4850 ft (1478 m) levels of the former Homestake Gold Mine in Lead, South Dakota. Service- and flood water samples were also collected as comparative benchmarks. With a maximum depth of 8,000 ft, (2,438 m), this mine currently hosts the Sanford Laboratory and is the proposed location for the US Deep Underground Science and Engineering Laboratory (DUSEL). The uncased 4100L hole is a legacy of mining; whereas, the cased 4850 hole was drilled in 2009 in support of large cavity construction. Both were packered or valved to exclude mine air and sampled anaerobically using aseptic technique. Physical measurements, aquatic and dissolved gas chemistry, cell counts, and microbial community assessments (SSU rRNA libraries) were performed on all samples. This study represents the first at Sanford Lab/DUSEL specifically focused on the deep biosphere rather than mine microbiology. Fluids from the two holes differed markedly, with that from 4100L being characterized by NaHCO3 and 4850 by Na2SO4. pH values of 8.2 vs. 7.5, conductivities (μS) of 1790 vs. 7667 and alkalinities (mg/L) of 767 vs. 187 were obtained from 4100L and 4850, respectively. As expected, the deeper 4850L hole had the higher temperature (38 vs. 30 oC). Neither had measureable nitrate, but both had similar dissolved organic C (DOC) concentrations (0.8 vs. 0.9 mg/L). Sulfate was present at 337 vs. 4,470 mg/L in 4100L and 4850L. Major dissolved gases were N2 (91 and 81 vol%), O2 (12 and 16 vol%) and CH4 (0.07 and 3.35 vol%) in 4100L and 4850L. The δ13C of CH4 was -51 and -56.7 permil in 4100L and 4850, respectively. The uncorrected 14C age of DIC was calculated at 25,310 (+/- 220) and 47,700 (+/-3,100) years for the two fluids. Cell counts were 5.9e3 and 2.01e5 in 4100L and 4850. Microbial community structure was diverse in both holes and distinct from that of service water. A large proportion of rRNA library clones were

Improve biogas production from low-organic-content sludge through high-solids anaerobic co-digestion with food waste.

Science.gov (United States)

Liu, Chuanyang; Li, Huan; Zhang, Yuyao; Liu, Can

2016-11-01

Anaerobic co-digestion of sewage sludge and food waste was tested at two different total solid (TS) concentrations. In the low-solids group with TS 4.8%, the biogas production increased linearly as the ratio of food waste in substrate increased from 0 to 100%, but no synergetic effect was found between the two substrates. Moreover, the additive food waste resulted in the accumulation of volatile fatty acids and decelerated biogas production. Thus, the blend ratio of food waste should be lower than 50%. While in the high-solids group with TS 14%, the weak alkaline environment with pH 7.5-8.5 avoided excessive acidification but high concentration of free ammonia was a potential risk. However, good synergetic effect was found between the two substrates because the added food waste improved mass transfer in sludge cake. Thus, 50% was recommended as the optimum ratio of food waste in substrate because of the best synergetic effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anaerobic bacteria in the gut of terrestrial isopod Crustacean Porcellio scaber.

Science.gov (United States)

Kostanjsek, R; Lapanje, A; Rupnik, M; Strus, J; Drobne, D; Avgustin, G

2004-01-01

Anaerobic bacteria from Porcellio scaber hindgut were identified and, subsequently, isolated using molecular approach. Phylogenetic affiliation of bacteria associated with the hindgut wall was determined by analysis of bacterial 16S rRNA gene sequences which were retrieved directly from washed hindguts of P. scaber. Sequences from bacteria related to obligate anaerobic bacteria from genera Bacteroides and Enterococcus were retrieved, as well as sequences from 'A1 subcluster' of the wall-less mollicutes. Bacteria from the genus Desulfotomaculum were isolated from gut wall and cultivated under anaerobic conditions. In contrast to previous reports which suggested the absence of anaerobic bacteria in the isopod digestive system due to short retention time of the food in the tube-like hindgut, frequent renewal of the gut cuticle during the moulting process, and unsuccessful attempts to isolate anaerobic bacteria from this environment our results indicate the presence of resident anaerobic bacteria in the gut of P. scaber, in spite of apparently unsuitable, i.e. predominantly oxic, conditions.

Anaerobic bioleaching of metals from waste activated sludge

International Nuclear Information System (INIS)

Meulepas, Roel J.W.; Gonzalez-Gil, Graciela; Teshager, Fitfety Melese; Witharana, Ayoma; Saikaly, Pascal E.; Lens, Piet N.L.

2015-01-01

Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g −1 of copper, 487 μg g −1 of lead, 793 μg g −1 of zinc, 27 μg g −1 of nickel and 2.3 μg g −1 of cadmium. During the anaerobic acidification of 3 g dry weight L −1 waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner

Microbial diversity in a permanently cold and alkaline environment in Greenland.

Directory of Open Access Journals (Sweden)

Mikkel A Glaring

Full Text Available The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C and alkaline (above pH 10 environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic representatives of the Firmicutes and Bacteroidetes. The results suggest a stratification of the ikaite columns similar to that of classical soda lakes, with a light-exposed surface inhabited by primary producers and an anoxic subsurface. This was further supported by identification of major taxonomic groups with close relatives in soda lake environments, including members of the genera Rhodobaca, Dethiobacter, Thioalkalivibrio and Tindallia, as well as very abundant groups related to uncharacterised environmental sequences originally isolated from Mono Lake in California.

Evaluation of different types of anaerobic seed sludge for the high rate anaerobic digestion of pig slurry in UASB reactors.

Science.gov (United States)

Rico, Carlos; Montes, Jesús A; Rico, José Luis

2017-08-01

Three different types of anaerobic sludge (granular, thickened digestate and anaerobic sewage) were evaluated as seed inoculum sources for the high rate anaerobic digestion of pig slurry in UASB reactors. Granular sludge performance was optimal, allowing a high efficiency process yielding a volumetric methane production rate of 4.1LCH 4 L -1 d -1 at 1.5days HRT (0.248LCH 4 g -1 COD) at an organic loading rate of 16.4gCODL -1 d -1 . The thickened digestate sludge experimented flotation problems, thus resulting inappropriate for the UASB process. The anaerobic sewage sludge reactor experimented biomass wash-out, but allowed high process efficiency operation at 3days HRT, yielding a volumetric methane production rate of 1.7LCH 4 L -1 d -1 (0.236LCH 4 g -1 COD) at an organic loading rate of 7.2gCODL -1 d -1 . To guarantee the success of the UASB process, the settleable solids of the slurry must be previously removed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rapid establishment of thermophilic anaerobic microbial community during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester.

Science.gov (United States)

Tian, Zhe; Zhang, Yu; Li, Yuyou; Chi, Yongzhi; Yang, Min

2015-02-01

The purpose of this study was to explore how fast the thermophilic anaerobic microbial community could be established during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester. Stable thermophilic anaerobic digestion was achieved within 20 days from a mesophilic digester treating sewage sludge by adopting the one-step startup strategy. The succession of archaeal and bacterial populations over a period of 60 days after the temperature increment was followed by using 454-pyrosequencing and quantitative PCR. After the increase of temperature, thermophilic methanogenic community was established within 11 days, which was characterized by the fast colonization of Methanosarcina thermophila and two hydrogenotrophic methanogens (Methanothermobacter spp. and Methanoculleus spp.). At the same time, the bacterial community was dominated by Fervidobacterium, whose relative abundance rapidly increased from 0 to 28.52 % in 18 days, followed by other potential thermophilic genera, such as Clostridium, Coprothermobacter, Anaerobaculum and EM3. The above result demonstrated that the one-step startup strategy could allow the rapid establishment of the thermophilic anaerobic microbial community. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application conditions for ester cured alkaline phenolic resin sand

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Ren-he Huang

2016-07-01

Full Text Available Five organic esters with different curing speeds: propylene carbonate (i.e. high-speed ester A; 1, 4-butyrolactone; glycerol triacetate (i.e. medium-speed ester B; glycerol diacetate; dibasic ester (DBE (i.e. low-speed ester C, were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin. The relationships between the curing performances of the resin (including pH value, gel pH value, gel time of resin solution, heat release rate of the curing reaction and tensile strength of the resin sand and the amount of added organic ester and curing temperature were investigated. The results indicated the following: (1 The optimal added amount of organic ester should be 25wt.%-30wt.% of alkaline phenolic resin and it must be above 20wt.%-50 wt.% of the organic ester hydrolysis amount. (2 High-speed ester A (propylene carbonate has a higher curing speed than 1, 4-butyrolactone, and they were both used as high-speed esters. Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand; glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin. (3 High-speed ester A, medium-speed ester B (glycerol triacetate and low-speed ester C (dibasic ester, i.e., DBE should be used below 15 ìC, 35 ìC and 50 ìC, respectively. High-speed ester A or low-speed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand. (4 There should be a suitable solid content (generally 45wt.%-65wt.% of resin, alkali content (generally 10wt.%-15wt.% of resin and viscosity of alkaline phenolic resin (generally 50-300 mPa≤s in the preparation of alkaline phenolic resin. Finally, the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.

Structural analysis of alkaline β-mannanase from alkaliphilic Bacillus sp. N16-5: implications for adaptation to alkaline conditions.

Directory of Open Access Journals (Sweden)

Yueju Zhao

Full Text Available Significant progress has been made in isolating novel alkaline β-mannanases, however, there is a paucity of information concerning the structural basis for alkaline tolerance displayed by these β-mannanases. We report the catalytic domain structure of an industrially important β-mannanase from the alkaliphilic Bacillus sp. N16-5 (BSP165 MAN at a resolution of 1.6 Å. This enzyme, classified into subfamily 8 in glycosyl hydrolase family 5 (GH5, has a pH optimum of enzymatic activity at pH 9.5 and folds into a classic (β/α(8-barrel. In order to gain insight into molecular features for alkaline adaptation, we compared BSP165 MAN with previously reported GH5 β-mannanases. It was revealed that BSP165 MAN and other subfamily 8 β-mannanases have significantly increased hydrophobic and Arg residues content and decreased polar residues, comparing to β-mannanases of subfamily 7 or 10 in GH5 which display optimum activities at lower pH. Further, extensive structural comparisons show alkaline β-mannanases possess a set of distinctive features. Position and length of some helices, strands and loops of the TIM barrel structures are changed, which contributes, to a certain degree, to the distinctly different shaped (β/α(8-barrels, thus affecting the catalytic environment of these enzymes. The number of negatively charged residues is increased on the molecular surface, and fewer polar residues are exposed to the solvent. Two amino acid substitutions in the vicinity of the acid/base catalyst were proposed to be possibly responsible for the variation in pH optimum of these homologous enzymes in subfamily 8 of GH5, identified by sequence homology analysis and pK(a calculations of the active site residues. Mutational analysis has proved that Gln91 and Glu226 are important for BSP165 MAN to function at high pH. These findings are proposed to be possible factors implicated in the alkaline adaptation of GH5 β-mannanases and will help to further

Peritoneal dialysis peritonitis by anaerobic pathogens: a retrospective case series

OpenAIRE

Chao, Chia-Ter; Lee, Szu-Ying; Yang, Wei-Shun; Chen, Huei-Wen; Fang, Cheng-Chung; Yen, Chung-Jen; Chiang, Chih-Kang; Hung, Kuan-Yu; Huang, Jenq-Wen

2013-01-01

Background Bacterial infections account for most peritoneal dialysis (PD)-associated peritonitis episodes. However, anaerobic PD peritonitis is extremely rare and intuitively associated with intra-abdominal lesions. In this study, we examined the clinical characteristics of PD patients who developed anaerobic peritonitis. Methods We retrospectively identified all anaerobic PD peritonitis episodes from a prospectively collected PD registry at a single center between 1990 and 2010. Only patient...

Osteocalcin and bone-specific alkaline phosphatase in Sickle cell ...

African Journals Online (AJOL)

specific alkaline phosphatase (b-AP) total protein levels were evaluated as indicators of bone turnover in twenty patients with sickle cell haemoglobinopathies and in twenty normal healthy individuals. The serum bonespecific alkaline phosphatase ...

The aluminum chemistry and corrosion in alkaline solutions

International Nuclear Information System (INIS)

Zhang Jinsuo; Klasky, Marc; Letellier, Bruce C.

2009-01-01

Aluminum-alkaline solution systems are very common in engineering applications including nuclear engineering. Consequently, a thorough knowledge of the chemistry of aluminum and susceptibility to corrosion in alkaline solutions is reviewed. The aluminum corrosion mechanism and corrosion rate are examined based on current experimental data. A review of the phase transitions with aging time and change of environment is also performed. Particular attention is given to effect of organic and inorganic ions. As an example, the effect of boron is examined in detail because of the application in nuclear reactor power systems. Methods on how to reduce the corrosion rate of aluminum in alkaline solutions are also highlighted

Optimisation Study on the Production of Anaerobic Digestate ...

African Journals Online (AJOL)

Organic fraction of municipal solid waste (OFMSW) is a rich substrate for biogas and compost production. Anaerobic Digestate compost (ADC) is an organic fertilizer produced from stabilized residuals of anaerobic digestion of OFMSW. This paper reports the result of studies carried out to optimise the production of ADC from ...

Cation exchange properties of zeolites in hyper alkaline aqueous media.

Science.gov (United States)

Van Tendeloo, Leen; de Blochouse, Benny; Dom, Dirk; Vancluysen, Jacqueline; Snellings, Ruben; Martens, Johan A; Kirschhock, Christine E A; Maes, André; Breynaert, Eric

2015-02-03

Construction of multibarrier concrete based waste disposal sites and management of alkaline mine drainage water requires cation exchangers combining excellent sorption properties with a high stability and predictable performance in hyper alkaline media. Though highly selective organic cation exchange resins have been developed for most pollutants, they can serve as a growth medium for bacterial proliferation, impairing their long-term stability and introducing unpredictable parameters into the evolution of the system. Zeolites represent a family of inorganic cation exchangers, which naturally occur in hyper alkaline conditions and cannot serve as an electron donor or carbon source for microbial proliferation. Despite their successful application as industrial cation exchangers under near neutral conditions, their performance in hyper alkaline, saline water remains highly undocumented. Using Cs(+) as a benchmark element, this study aims to assess the long-term cation exchange performance of zeolites in concrete derived aqueous solutions. Comparison of their exchange properties in alkaline media with data obtained in near neutral solutions demonstrated that the cation exchange selectivity remains unaffected by the increased hydroxyl concentration; the cation exchange capacity did however show an unexpected increase in hyper alkaline media.

Borders of life: lessons from Microbiology of deep-sea hydrothermal vents

Science.gov (United States)

Prieur, D.

Thirty years ago, the deep-sea was known as a low density biotope due to coldness, darkness and famine-like conditions. The discovery of deep-sea hydrothermal vents in the Eastern Pacific in 1977 and the associated black smokers in 1979 considerably changed our views about life on Earth. For the first time, an ecosystem almost independent (at least for tens of years) of solar nergy was discovered. Besides the spectacular and unexpected communities of invertebrates based on symbiotic associations with chemo-litho-autotrophic bacteria, prokaryotic communities associated with high temperature black smokers fascinated microbiologists of extreme environments. Within mineral structures where temperature gradients may fluctuate from ambient seawater temperatures (2°C) up to 350°C, thermophilic (optimal growth above 60°C) and hyperthermophilic (optimal growth above 80°C) microorganisms thrived under very severe conditions due to elevated hydrostatic pressure, toxic compounds or strong ionizing radiations. These organisms belong to both domains of Bacteria and Archaea and live aerobically but mostly anaerobically, using a variety of inorganic and organic carbon sources, and a variety of electron donnors and acceptors as well. The most thermophilic organism known on Earth was isolated from a mid-Atlantic-Ridge hydrotermal vent: Pyrolobus fumarii grows optimally at 110°c and its upper temperature limit for life is 113°C. Such an organism survived to autoclaving conditions currently used for sterilization procedures. Many other hyperthermophilic organisms were isolated and described, including fermenters, sulphate and sulphur reducers, hydrogen oxidizers, nitrate reducers, methanogens, etc. Although most of anaerobes are killed when exposed to oxygen, several deep-sea hyperthermophiles appeared to survive to both oxygen and starvation exposures, indicating that they probably can colonize rather distant environments Because of elevated hydrostatic pressure that exists at

Anaerobic Co-Digestion of the Microalgae Scenedesmus Sp.

Energy Technology Data Exchange (ETDEWEB)

Ramos-Suarez, J. L.; Carreras, N.

2011-06-07

Microalgae biomass has been widely studied for biogas production over the last years and results show that anaerobic digestion is often limited by the low C/N ratio of this type of biomass. Therefore, codigestion with substrates of high C/N ratio is necessary. The objectives of this study are to set up an experimental method that ease reproducibility and control of anaerobic digestion processes in laboratory conditions and to determine the biodegradability and biogas production potential of the co-digestion process of microalgae Scenedesmus sp. and energy crop Opuntia ficus indica (L.) Miller. Results obtained showed that higher C/N ratios are preferred in order to maximize methane production. Highest methane yield obtained was 0.252m3CH4/Kg VS and degradability expressed as percentage COD reduced is around 30% for the ideal mixture found, made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. A laboratory setup using MicroOxymax respirometer, after its adaptation to work under anaerobic conditions, can be used for the monitoring of anaerobic digestion processes. Scenedesmus sp. as sole substrate for anaerobic digestion does not give good results due to low C/N ratio. However, when codigesting it with O. ficus-indica methane production is satisfactory. Best mixture was made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. (Author)

On using rational enzyme redesign to improve enzyme-mediated microbial dehalogenation of recalcitrant substances in deep-subsurface environments

International Nuclear Information System (INIS)

Ornstein, R.L.

1993-06-01

Heavily halogenated hydrocarbons are one of the most prevalent classes of man-made recalcitrant environmental contaminants and often make their way into subsurface environments. Biodegradation of heavily chlorinated compounds in the deep subsurface often occurs at extremely slow rates because native enzymes of indigenous microbes are unable to efficiently metabolize such synthetic substances. Cost-effective engineering solutions do not exist for dealing with disperse and recalcitrant pollutants in the deep subsurface (i.e., ground water, soils, and sediments). Timely biodegradation of heavily chlorinated compounds in the deep subsurface may be best accomplished by rational redesign of appropriate enzymes that enhance the ability of indigenous microbes to metabolize these substances. The isozyme family cytochromes P450 are catalytically very robust and are found in all aerobic life forms and may be active in may anaerobes as well. The author is attempting to demonstrate proof-of-principle rational enzyme redesign of cytochromes P450 to enhance biodehalogenation

Isolation of obligate anaerobic bacteria from ulcerative keratitis in domestic animals.

Science.gov (United States)

Ledbetter, Eric C; Scarlett, Janet M

2008-01-01

To determine the frequency of obligate anaerobic bacterial isolation from corneal samples of domestic animals with ulcerative keratitis and to characterize the historical, clinical, cytological, and microbiological features of culture-positive cases. Three hundred and thirty domestic animals with ulcerative keratitis. Anaerobic bacteriologic culture and Gram stain were performed on corneal samples from consecutive animals examined with suspect septic ulcerative keratitis. Additional corneal diagnostics included: aerobic bacteriologic culture for all species; fungal culture for ungulates; Mycoplasma culture and virus isolation or feline herpesvirus-1 (FHV-1) polymerase chain reaction (PCR) for cats. Historical, clinical, and cytological findings were correlated with microbiologic data. Anaerobic bacteria were isolated from 13.0% of corneal samples (dogs: 14.0%; horses: 12.9%; cats: 7.9%; alpacas: 18.8%). The most frequent isolates were Clostridium, Peptostreptococcus, Actinomyces, Fusobacterium, and Bacteroides species. The majority of these infections were mixed anaerobic and aerobic bacteria, unless antimicrobial therapy had been administered prior to presentation. The clinical appearance of anaerobic bacterial culture-positive cases was highly variable. Ocular trauma, pre-existing corneal disease, previous corneal surgery, and chronic dermatological disease were significantly (P anaerobic cultures in one or more species. The results of the present study demonstrate that obligate anaerobic bacteria are present within the intralesional flora of ulcerative keratitis in domestic animals. In most species evaluated, these bacteria were identified infrequently. Anaerobic bacterial infection of the cornea most frequently occurs in association with other ocular pathogens and previous corneal abnormalities.

Anaerobic respiration of Escherichia coli in the mouse intestine.

Science.gov (United States)

Jones, Shari A; Gibson, Terri; Maltby, Rosalie C; Chowdhury, Fatema Z; Stewart, Valley; Cohen, Paul S; Conway, Tyrrell

2011-10-01

The intestine is inhabited by a large microbial community consisting primarily of anaerobes and, to a lesser extent, facultative anaerobes, such as Escherichia coli, which we have shown requires aerobic respiration to compete successfully in the mouse intestine (S. A. Jones et al., Infect. Immun. 75:4891-4899, 2007). If facultative anaerobes efficiently lower oxygen availability in the intestine, then their sustained growth must also depend on anaerobic metabolism. In support of this idea, mutants lacking nitrate reductase or fumarate reductase have extreme colonization defects. Here, we further explore the role of anaerobic respiration in colonization using the streptomycin-treated mouse model. We found that respiratory electron flow is primarily via the naphthoquinones, which pass electrons to cytochrome bd oxidase and the anaerobic terminal reductases. We found that E. coli uses nitrate and fumarate in the intestine, but not nitrite, dimethyl sulfoxide, or trimethylamine N-oxide. Competitive colonizations revealed that cytochrome bd oxidase is more advantageous than nitrate reductase or fumarate reductase. Strains lacking nitrate reductase outcompeted fumarate reductase mutants once the nitrate concentration in cecal mucus reached submillimolar levels, indicating that fumarate is the more important anaerobic electron acceptor in the intestine because nitrate is limiting. Since nitrate is highest in the absence of E. coli, we conclude that E. coli is the only bacterium in the streptomycin-treated mouse large intestine that respires nitrate. Lastly, we demonstrated that a mutant lacking the NarXL regulator (activator of the NarG system), but not a mutant lacking the NarP-NarQ regulator, has a colonization defect, consistent with the advantage provided by NarG. The emerging picture is one in which gene regulation is tuned to balance expression of the terminal reductases that E. coli uses to maximize its competitiveness and achieve the highest possible population in

Covering Materials for Anaerobic Digesters Producing Biogas

International Nuclear Information System (INIS)

Itodo, I. N.; Philips, T. K.

2002-01-01

The suitability of foam, concrete and clay soil as covering material on anaerobic digesters producing biogas was investigated using four batch-type digesters of 20 litres volume. The methane yield from the digesters was of the order: foam >control> concrete > clay soil. The digester covered with foam had the highest methane yield, best temperature control and most favourable pH conditions. It is most suitable as cover material on anaerobic digesters

Assessment of the anaerobic degradation of six active pharmaceutical ingredients.

Science.gov (United States)

Musson, Stephen E; Campo, Pablo; Tolaymat, Thabet; Suidan, Makram; Townsend, Timothy G

2010-04-01

Research examined the anaerobic degradation of 17 alpha-ethynylestradiol, acetaminophen, acetylsalicylic acid, ibuprofen, metoprolol tartrate, and progesterone by methanogenic bacteria. Using direct sample analysis and respirometric testing, anaerobic degradation was examined with (a) each compound as the sole organic carbon source and (b) each compound at a lower concentration (250 microg/L) and cellulose serving as the primary organic carbon source. The change in pharmaceutical concentration was determined following 7, 28, 56, and 112 days of anaerobic incubation at 37 degrees C. Only acetylsalicylic acid demonstrated significant degradation; the remaining compounds showed a mixture of degradation and abiotic removal mechanisms. Experimental results were compared with BIOWIN, an anaerobic degradation prediction model of the US Environmental Protection Agency. The BIOWIN model predicted anaerobic biodegradability of the compounds in the order: acetylsalicylic acid > metoprolol tartrate > ibuprofen > acetaminophen > 17 alpha-ethinylestradiol >progesterone. This corresponded well with the experimental findings which found degradability in the order: acetylsalicylic acid > metoprolol tartrate > acetaminophen > ibuprofen. (c) 2010 Elsevier B.V. All rights reserved.

Microbiology of anaerobic digestion; Microbiologia da digestao anaerobica

Energy Technology Data Exchange (ETDEWEB)

Novaes, Rosana Filomena Vazoller [CETESB, Sao Paulo, SP (Brazil)

1988-12-31

Considerations was made about the microorganisms involved in the anaerobic digestion of wastes. Are also presented, the main results on this subject obtained, until now, in the studies carried on the group of anaerobic microbiology researchers from the Sanitary Company of Sao Paulo State, Brazil. (author) 23 refs., 8 figs., 3 tabs.

Rumen derived anaerobic digestion of water hyacinth (Eicchornia ...

African Journals Online (AJOL)

STORAGESEVER

2009-09-01

Sep 1, 2009 ... The agar plates were then incubated anaerobically at 37°C for 24 h. The digesters were seeded with rumen bacteria and immersed into water bath operated at 37°C. During the anaerobic digestion, volume of biogas produced was recorded accordingly. This paper, therefore, suggests ways by which water.

Utilization of steam- and explosion-decompressed aspen wood by some anaerobes

Energy Technology Data Exchange (ETDEWEB)

Khan, A W; Asther, M; Giuliano, C

1984-01-01

Tests made to study the suitability of using steam- and explosion-decompressed aspen wood as a substrate in anaerobic fermentations indicated that after washing with dilute NaOH it becomes less than 80% accessible to both mesophilic and thermophilic cellulolytic anaerobes and cellulases, compared with delignified, ball-milled pulp. After washing, this material was also suitable for the single-step conversion of cellulose to EtOH using cocultures consisting of cellulolytic and EtOH-producing saccharolytic anaerobes; and without and after washing by the use of cellulolytic enzymes and ethanologenic anaerobes.

Analysis of anaerobic product properties in fluid and aggressive environments

OpenAIRE

Goncharov, A.; Tulinov, A.

2008-01-01

The article presents the results of experiments involved in investigation of properties of some domestic and foreign-made anaerobic materials in components and units operating in fluid and aggressive environments. These experiments determined the strength and swell values of anaerobic products in the sea water, fuel and oil, and confirmed their anticorrosion properties. The experiments demonstrated high resistance of anaerobic products to various fluids and aggressive environments, which make...

Alkaline Activator Impact on the Geopolymer Binders

Science.gov (United States)

Błaszczyński, Tomasz Z.; Król, Maciej R.

2017-10-01

Concrete structures are constantly moving in the direction of improving the durability. Durability depends on many factors, which are the composition of concrete mix, the usage of additives and admixtures and the place, where material will work and carry the load. The introduction of new geopolymer binders for geopolymer structures adds a new aspect that is type of used activator. This substance with strongly alkaline reaction is divided because of the physical state, the alkaline degree and above all the chemical composition. Taking into account, that at present the geopolymer binders are made essentially from waste materials or by-products from the combustion of coal or iron ore smelting, unambiguous determination of the effect of the activator on the properties of the geopolymer material requires a number of trials, researches and observation. This paper shows the influence of the most alkaline activators on the basic parameters of the durability of geopolymer binders. In this study there were used highly alkaline hydroxides, water glasses and granules, which are waste materials in a variety of processes taking place in chemical plants. As the substrate of geopolymer binders there were used fly ash which came from coal and high calcareous ash from the burning of lignite.

Alkaline fuel cell technology in the lead

International Nuclear Information System (INIS)

Nor, J.K.

2004-01-01

The Alkaline Fuel Cell (AFC) was the first fuel cell successfully put into practice, a century after William Grove patented his 'hydrogen battery' in 1839. The space program provided the necessary momentum, and alkaline fuel cells became the power source for both the U.S. and Russian manned space flight. Astris Energi's mission has been to bring this technology down to earth as inexpensive, rugged fuel cells for everyday applications. The early cells, LABCELL 50 and LABCELL 200 were aimed at deployment in research labs, colleges and universities. They served well in technology demonstration projects such as the 1998 Mini Jeep, 2001 Golf Car and a series of portable and stationary fuel cell generators. The present third generation POWERSTACK MC250 poised for commercialization is being offered to AFC system integrators as a building block of fuel cell systems in numerous portable, stationary and transportation applications. It is also used in Astris' own E7 and E8 alkaline fuel cell generators. Astris alkaline technology leads the way toward economical, plentiful fuel cells. The paper highlights the progress achieved at Astris, improvements of performance, durability and simplicity of use, as well as the current and future thrust in technology development and commercialization. (author)

Actinide-Aluminate Speciation in Alkaline Radioactive Waste

International Nuclear Information System (INIS)

Clark, David L.; Fedosseev, Alexander M.

2001-01-01

Investigation of behavior of actinides in alkaline media containing AL(III) showed that no aluminate complexes of actinides in oxidation states (IIII-VIII) were formed in alkaline solutions. At alkaline precipitation IPH (10-14) of actinides in presence of AL(III) formation of aluminate compounds is not observed. However, in precipitates contained actinides (IIV)<(VI), and to a lesser degree actinides (III), some interference of components takes place that is reflected in change of solid phase properties in comparison with pure components or their mechanical mixture. The interference decreases with rise of precipitation PH and at PH 14 is exhibited very feebly. In the case of NP(VII) the individual compound with AL(III) is obtained, however it is not aluminate of neptunium(VII), but neptunate of aluminium(III) similar to neptunates of other metals obtained earlier

Serum alkaline phosphatase screening for vitamin D deficiency states

International Nuclear Information System (INIS)

Shaheen, S.; Barrakzai, Q.

2012-01-01

Objective: To determine whether serum vitamin D levels are correlated with serum levels of alkaline phosphatase or not. Study Design: Cross-sectional, observational study. Place and Duration of Study: Multi-centre study, conducted at Liaquat National Hospital and Medical College, National Medical Centre and Medicare Hospital, Karachi, from January to October 2009. Methodology: Patients attending the Orthopaedic OPDs with complaints of pain in different body regions and serum vitamin D/sub 3/ levels of greater or equal to 30 ng/ml were included in the study. Patients with vitamin D deficiency were further categorized into mild deficiency or insufficiency (vit. D/sub 3/ = 20-29 ng/ml), moderate deficiency (vit. D/sub 3/ = 5 - 19 ng/ml) and severe deficiency forms (vit. D/sub 3/ < 5 ng/ml). Pearson correlation was applied to test the correlation of serum alkaline phosphatase levels with serum vitamin D/sub 3/ levels. P-value < 0.05 was considered to be significant. Results: Out of 110 samples, 26 had mild (23%), 61 had moderate (55%) and 21 had severe (19.1%) vitamin D deficiencies. All of the patients in the three groups had alkaline phosphatase with in normal limits and the total mean value of the enzyme was 135.97 +- 68.14I U/L. The inter group comparison showed highest values of alkaline phosphatase in the moderate vitamin D deficiency group. The correlation coefficient of alkaline phosphatase and serum vitamin D/sub 3/ levels was r =0.05 (p =0.593). Conclusion: Serum vitamin D/sub 3/ levels may not be correlated with increased serum alkaline phosphatase levels. Therefore, alkaline phosphatase may not be used as a screening test to rule out vitamin D deficiency. (author)

Mixing effect on thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste

KAUST Repository

Ghanimeh, Sophia A.

2012-08-01

This paper examines the effect of mixing on the performance of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste during the start-up phase and in the absence of an acclimated seed. For this purpose, two digesters were used under similar starting conditions and operated for 235days with different mixing schemes. While both digesters exhibited a successful startup with comparable specific methane yield of 0.327 and 0.314l CH 4/gVS, continuous slow stirring improved stability by reducing average VFA accumulation from 2890 to 825mg HAc/l, propionate content from 2073 to 488mg/l, and VFA-to-alkalinity ratio from 0.32 to 0.07. As a result, the startup with slow mixing was faster and smoother accomplishing a higher loading capacity of 2.5gVS/l/d in comparison to 1.9gVS/l/d for non-mixing. Mixing equally improved microbial abundance from 6.6 to 10gVSS/l and enhanced solids and soluble COD removal. © 2012 Elsevier Ltd.

Mixing effect on thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste

KAUST Repository

Ghanimeh, Sophia A.; El-Fadel, Mutasem E.; Saikaly, Pascal

2012-01-01

This paper examines the effect of mixing on the performance of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste during the start-up phase and in the absence of an acclimated seed. For this purpose, two digesters were used under similar starting conditions and operated for 235days with different mixing schemes. While both digesters exhibited a successful startup with comparable specific methane yield of 0.327 and 0.314l CH 4/gVS, continuous slow stirring improved stability by reducing average VFA accumulation from 2890 to 825mg HAc/l, propionate content from 2073 to 488mg/l, and VFA-to-alkalinity ratio from 0.32 to 0.07. As a result, the startup with slow mixing was faster and smoother accomplishing a higher loading capacity of 2.5gVS/l/d in comparison to 1.9gVS/l/d for non-mixing. Mixing equally improved microbial abundance from 6.6 to 10gVSS/l and enhanced solids and soluble COD removal. © 2012 Elsevier Ltd.