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Sample records for biological aerated filter

  1. Hydrodynamic behaviour of the lateral flow biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    HE Qiang; WANG Yin; FANG Jun-hua; ZHANG Hong-jing; XU Jing

    2006-01-01

    Pulsed signal experiment was carried out to determine the hydrodynamic behaviours of lateral flow biological aerated filter(LBAF). With the analysis of experimental results, LBAF is viewed as an approximate plug flow reactor, and hydraulic retention time distribution function was derived based on LBAF. The results show that flow rate and aeration strength are two critical factors which influence flow patterns in LBAF reactor. The hydrodynamic behaviour analysis of LBAF is the theoretical basis of future research on improving capacity factor and developing kinetic model for the reactor.

  2. Characteristics of integrated biological aerated filter in municipal wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    HE Qiang; ZHANG Yu-ping; XU Jian-bin

    2005-01-01

    In this paper, the characteristics of integrated biological aerated filter (IBAF) applied to municipal wastewater treatment were studied in a pilot scale experiment. The experimental results showed that IBAF has high efficiencies in removing organic pollutants, such as CODCr and SS, in municipal wastewater. The removal rates of CODCr and SS can reach over 90% and 80%, respectively, when COD and SS in the influent are 234 mg L-1 and 112 mg L-1, hydraulic retention time (HRT) is 8 h, and the aerated intensity is in the range of (0.5 to 0.6) L m-2 s-1.

  3. Atrazine Removal from Aqueous Solutions using Submerged Biological Aerated Filter

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Baghapour

    2013-06-01

    Full Text Available Atrazine is widely used in the agriculture as an herbicide. Due to its high mobility, Atrazine leaks into the groundwaters, surface waters, and drinking water wells. Many physical and chemical methods have been suggested for removing Atrazine from aquatic environments. However, these methods are very costly, have many performance problems, produce a lot of toxic intermediates which are very harmful and dangerous, and cannot completely mineralize Atrazine. In this study, biodegradation of Atrazine by microbial consortium was evaluated in the aquatic environment. In order to assess the Atrazine removal from the aquatic environment, submerged biological aerated filter (SBAF was fed with synthetic wastewater based on sucrose and Atrazine at different hydraulic retention times (HRTs. The maximum efficiencies for Atrazine and Soluble Chemical Oxygen Demand (SCOD removal were 97.9% and 98.9%, respectively. The study findings showed that Stover-Kincannon model had very good fitness (R2 > 99% in loading Atrazine in the biofilter and by increasing the initial concentration of Atrazine, the removal efficiency increased. Aerobic mixed biofilm culture was observed to be suitable for the treatment of Atrazine from aquatic environment. There was no significant inhibition effect on mixed aerobic microbial consortia. Atrazine degradation depended on the strength of wastewater and the amount of Atrazine in the influent

  4. Performances of lateral flow biological aerated filter in treating domestic wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-jing; LONG Teng-rui; CAO Yan-xiao

    2006-01-01

    A new biological aerated filter--lateral flow biological aerated filter(LBAF) is developed.The effects of air/water ratio,hydraulic loading and the length of LBAF on pollutants removal efficiency are tested.The results show that under optimal technological conditions when hydraulic loading is 0.43 m3 m(2 h(1 and air/water ratio is 10:1,the average removal efficiencies of COD,SS,NH3-N,and TN reach 88.01%,95.18%,78.97% and 52.58%,respectively.An LBAF has a large pollutants handling capacity; is less liable to be blocked,and has a longer operation cycle in comparison with a traditional BAF.

  5. Enhanced Nutrient Removal with Upflow Biological Aerated Filter for Reclaimed Water

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-dong; PENG Yong-zhen; WANG Shu-ying; ZHANG Yan-ping

    2007-01-01

    A two-stage upflow biological aerated filter was designed as an advanced treatment process to optimize the operating parameters and study the correlative factors influencing the efficiency of nitrification, denitrification and phosphorus removal. The experimental results showed that the final effluent of the two-stage upflow biofilter process operated in series could meet the stringent limits of the reclaimed water for the total nitrogen of 2mg/L, and total phosphorus of 0.3mg/L. The high treatment efficiency allowed the reactor operating at very high hydraulic loadings and reaching nearly complete nitrification and denitrification.

  6. Performance of simultaneous nitrification and denitrification in lateral flow biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    LONG Teng-rui; CAO Yan-xiao; ZHANG Hong-jing; GAO Xiao-tao

    2006-01-01

    A new wastewater treatment facility-lateral flow biological aerated filter (LBAF) was developed aiming at solving energy consumption and operational problems in wastewater treatment facilities in small towns. It has the function of nitrification and removing organic substrate. In this study, we focused on the denitrification performance of LBAF and its possible mechanism under thorough aeration. We identified the existence of simultaneous nitrification and denitrification (SND)by analyzing nitrogenous compounds along the flow path of LBAF and supportive microbial microscopy, and studied the effects of air/water ratio and hydraulic loading on the performance of nitrogen removal and on SND in LBAF to find out the optimal operation condition. It is found that for saving operation cost, aeration can be reduced to some degree that allows desirable removal efficiency of pollutants, and the optimal air/water ratio is 10:1. Hydraulic loading less than 0.43 m h-1 hardly affects the nitrification and denitrification performance; whereas higher hydraulic loading is unfavorable to both nitrification and denitrification, far more unfavorable to denitrification than to nitrification.

  7. Treatment of Slightly Polluted Wastewater in an Oil Refinery Using a Biological Aerated Filter Process

    Institute of Scientific and Technical Information of China (English)

    XIE Wenyu; ZHONG Li; CHEN Jianjun

    2007-01-01

    The slightly polluted wastewater from oil refinery contains some COD, oil pollutants and suspended solids (SS). A small-scale fixed film biological aerated filter (BAF) process was used to treat the wastewater. The influences of hydraulic retention time (HRT), air/water volume flow ratio and backwashing cycle on treatment efficiencies were investigated. The wastewater was treated by the BAF process under optimal conditions: the HRT of backwashing cycle of every 4-7 days. The results showed that the average removal efficiency of COD, oil pollutants and SS was 84.5%, 94.0% and 83.4%, respectively. And the average effluent concentration of COD, oil pollutants and SS was 12.5, 0.27, 14.5the BAF process is a suitable and highly efficient method to treat the wastewater.

  8. Effect of media heights on the performance of biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    HU Yong-you; WANG Li-li

    2005-01-01

    The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, CODCr and NH4+ -N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, CODCr and NH4+-N was 79.1%, 63.9% and 96.4% respectively under the influent CODCr and NH4+ -N of 122.1 mgCODCr/L and 14.84 mgNH4+ -N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3: 1.

  9. Process of inorganic nitrogen transformation and design of kinetics model in the biological aerated filter reactor.

    Science.gov (United States)

    Yan, Gang; Xu, Xia; Yao, Lirong; Lu, Liqiao; Zhao, Tingting; Zhang, Wenyi

    2011-04-01

    As one of the plug-flow reactors, biological aerated filter (BAF) reactor was divided into four sampling sectors to understand the characteristics of elemental nitrogen transformation during the reaction process, and then the different characteristics of elemental nitrogen transformation caused by different NH(3)-N loadings, biological quantities and activities in each section were obtained. The results showed that the total transformation ratio in the nitrifying reactor was more than 90% in the absence of any organic carbon resource, at the same time, more than 65% NH(3)-N in the influent were nitrified at the filter height of 70 cm below under the conditions of the influent runoff 9-19 L/h, the gas-water ratio 4-5:1, the dissolved oxygen 3.0-5.8 mg/L and the NH(3)-N load 0.28-0.48 kg NH(3)-N/m(3) d. On the base of the Eckenfelder mode, the kinetics equation of the NH(3)-N transformation along the reactor was S(e)=S(0) exp(-0.0134D/L(1.2612)).

  10. Combined Application of UV Photolysis and Ozonation with Biological Aerating Filter in Tertiary Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Zhaoqian Jing

    2012-01-01

    Full Text Available To enhance the biodegradability of residual organic pollutants in secondary effluent of wastewater treatment plants, UV photolysis and ozonation were used in combination as pretreatment before a biological aerating filter (BAF. The results indicated that UV photolysis could not remove much COD (chemical oxygen demand, and the performance of ozonation was better than the former. With UV photolysis combined with ozonation (UV/O3, COD removal was much higher than the sum of that with UV photolysis and ozonation alone, which indicated that UV photolysis could efficiently promote COD removal during ozonation. This pretreatment also improved molecular weight distribution (MWD and biodegradability greatly. Proportion of organic compounds with molecular weight (MW <3 kDalton was increased from 51.9% to 85.9%. COD removal rates with BAF and O3/BAF were only about 25% and 38%, respectively. When UV/O3 oxidation was combined with BAF, the average COD removal rate reached above 61%, which was about 2.5 times of that with BAF alone. With influent COD ranging from 65 to 84 mg/L, the effluent COD was stably in the scope of 23–31 mg/L. The combination of UV/O3 oxidation with BAF was quite efficient in organic pollutants removal for tertiary wastewater treatment.

  11. Application of integrated ozone biological aerated filters and membrane filtration in water reuse of textile effluents.

    Science.gov (United States)

    He, Yaozhong; Wang, Xiaojun; Xu, Jinling; Yan, Jinli; Ge, Qilong; Gu, Xiaoyang; Jian, Lei

    2013-04-01

    A combined process including integrated ozone-BAFs (ozone biological aerated filters) and membrane filtration was first applied for recycling textile effluents in a cotton textile mill with capacity of 5000 m(3)/d. Influent COD (chemical oxygen demand) in the range of 82-120 mg/L, BOD5 (5-day biochemical oxygen demand) of 12.6-23.1 mg/L, suspended solids (SSs) of 38-52 mg/L and color of 32-64° were observed during operation. Outflows with COD≤45 mg/L, BOD5≤7.6 mg/L, SS≤15 mg/L, color≤8° were obtained after being decontaminated by ozone-BAF with ozone dosage of 20-25 mg/L. Besides, the average removal rates of PVA (polyvinyl alcohol) and UV254 were 100% and 73.4% respectively. Permeate water produced by RO (reverse osmosis) could be reused in dyeing and finishing processes, while the RO concentrates could be discharged directly under local regulations with COD≤100 mg/L, BOD5≤21 mg/L, SS≤52 mg/L, color≤32°. Results showed that the combined process could guarantee water reuse with high quality, and solve the problem of RO concentrate disposal.

  12. Simultaneous nutrients and carbon removal from low-strength domestic wastewater with an immobilised-microorganism biological aerated filter.

    Science.gov (United States)

    Chen, Q; Qu, L; Tong, G; Ni, J

    2011-01-01

    To improve the efficiency of low-strength domestic wastewater treatment, an immobilised-microorganism biological aerated filter (I-BAF) was established for simultaneous carbon, nitrogen and phosphorus removal. The I-BAF performance was systematically evaluated under continuous and intermittent aeration modes. At the optimal condition with an intermittent aeration control schedule of 2 h on/1 h off, the maximum removal rates of COD, NH(4)(+)-N, TN and P were 82.54%, 94.83%, 51.85% and 61.49%, respectively, and the corresponding averaged effluents could meet the first class standards of China. Further analysis of PCR-DGGE profile revealed that members of the gamma and alpha proteobacterium bacterial groups were probably responsible for the nitrogen and phosphorus removal. The I-BAF system showed excellent performance in carbon and nutrients removal, which provided a cost-effective solution for the treatment of low-strength domestic wastewater.

  13. Using a biological aerated filter to treat mixed water-borne volatile organic compounds and assessing its emissions

    Institute of Scientific and Technical Information of China (English)

    CHENG Wen-Hsi

    2009-01-01

    A biological aerated filter (BAF) was evaluated as a fixed-biofilm processes to remove water-borne volatile organic compounds (VOCs) from a multiple layer ceramic capacitor (MLCC) manufacturing plant in southern Taiwan.The components of VOC were identified to be toluene,1,2,4-trimethylbenzene,1,3,5-trimethylbenzene,bromodichloromethane and isopropanol (IPA).The full-scale BAF was constructed of two separate reactors in series,respectively using 10-cm and 15-cm diameter polypropylene balls as the packing materials and a successful preliminary bench-scale experiment was performed to feasibility.Performance results show that the BAF removed over 90% chemical oxygen demand (COD) from the influent with (1188 ± 605) mg/L of COD.A total organic loading of 2.76 kg biochemical oxygen demand (BOD)/(m~3 packing·d) was determined for the packed bed,in which the flow pattern approached that of a mixed flow.A limited VOC concentration of (0.97 ± 0.29) ppmv (as methane) was emitted from the BAF system.Moreover,the emission rate of VOC was calculated using the proposed formula,based on an air-water mass equilibrium relationship,and compared to the simulated results obtained using the Water 9 model.Both estimation approaches of calculation and model simulation using Water 9 evaluating VOC emissions reveal that 0.1% IPA (0.0031-0.0037 kg/d) was aerated into a gaseous phase,and 30% to 40% (0.006-0.008 kg/d) of the toluene was aerated.

  14. Synergism of Novel Sequence Bio-ecological Process and Biological Aerated Filter for Sewage Treatment in Cold Climate

    Institute of Scientific and Technical Information of China (English)

    张鹏; 海热提; 周东凯; 何一群; 白志远

    2011-01-01

    A lab-scale integrated treatment system including the novel sequence bio-ecological process (SBEP) and biological aerated filter (BAF) for a sewage mixture (chemistry laboratory wastewater and domestic sewage) was presented in this paper. The main objective of the study was to test the contribution of artificial aeration, recir-culation ratio and mass concentration of steel slag on pollutant removal in winter when the plants are dormant. It had been shown that SBEP and BAF play different roles in removing contaminants from wastewater. During the airflow experiment, the removal efficiency of COD and TP in SBEP was higher than that in BAF, whereas BAF can compensate for the deficiency of SBEP where no significant improvement on ammonium nitrogen removal is ob-served. Yet, the removal etticiencies of COD,TP and NH4^+ -N in SBEP could be improved apparently when ditterent recireulation ratio or various mass concentration of steel were applied. Especially, when the airflow of 0.06 L·h^-1, the recirculation ratio rate of 80% and the mass concentration of steel of 2.2-2.4 g·L^-1 were applied, thehighest efficiency of 94.6%, 77.9% and 80.7% for COD, TP and NH4^+ -N were achieved,-respectively,The integrated treatment system of SBEP and BAF was proved to be an effective wastewater treatment technique and a better alternative to treat domestic sewage.

  15. A performance evaluation of a new iron oxide-based porous ceramsite (IPC) in biological aerated filters.

    Science.gov (United States)

    Bao, Teng; Chen, Tianhu; Ezzatahmadi, Naeim; Rathnayake, Suramya I; Chen, Dong; Wille, Marie-Luise; Frost, Ray

    2017-04-01

    A novel medium containing iron oxide-based porous ceramsite (IPC) and commercial ceramsite (CC) was used in two laboratory-scale upflow biological aerated filters (BAFs) to treat city wastewater to compare their efficacy in wastewater treatment. The IPC BAF and CC BAF were operated in water at 20-26°C, an air/water (A/W) ratio of: 3:1 and hydraulic retention times (HRTs) of 7, 3.5, 1.75, and 0.5 h and the removal of ammonia nitrogen (NH3-N), total nitrogen (TN), total organic carbon (TOC), and phosphorus (P) were studied. Our results indicated that IPC BAF was superior to CC BAF in terms of TOC, TN, NH3-N, and P removal. IPC had higher total porosity and larger total surface area than CC. The interconnected porous structure of IPC was suitable to microbial growth, protozoan, and metazoan organisms were primarily found in the accumulated biofilm layer. Biomass, in the biofilm layer, was detected at three distinct distances (300, 900, and 1500 mm) from the bottom of the inlet filter, again indicating that the IPC was more suitable for biomass growth. The presence of biomass improves the simultaneous removal efficiency of nitrogen and phosphorus in the IPC BAF. Thus, our findings support IPC as a material for use in filter media in wastewater treatment BAFs.

  16. Comparison of combined and separated biological aerated filter (BAF) performance for pre-denitrification/nitrification of municipal wastewater.

    Science.gov (United States)

    Rother, E; Cornel, P; Ante, A; Kleinert, P; Brambach, R

    2002-01-01

    The performance of two systems of semi-industrial up-flow biological aerated filters (BAF) with pre-denitrification followed by nitrification was studied and compared under various operating and loading conditions. The first system consisted of two separate reactors for the denitrification and the nitrification step, whereas in the second system the aerobic nitrification zone was packed on top of the anoxic denitrification zone in one reactor. The second system potentially offers substantial savings in investment costs and space requirements for a large scale treatment plant. Regarding the elimination of carbonaceous pollution and denitrification the systems did not show significant differences. However, nitrification in the combined system suffered from the mixing of different biocenosis by daily backwashing and was reduced to 50-70% of the separated system's performance. Factors such as oxygen concentration, raw water composition and loading rates affected both systems' nitrification rates in similar ways. Since it is impossible to optimise the nitrification and denitrification processes separately, the combined system should only be considered for large scale applications if space is very scarce and if a stable raw water composition can be expected. If strict limit values for nitrate have to be met in the effluent, a combination of pre- and post-denitrification is advantageous and advisable.

  17. Combination of ozonation, activated carbon, and biological aerated filter for advanced treatment of dyeing wastewater for reuse.

    Science.gov (United States)

    Zou, Xiao-Ling

    2015-06-01

    Laboratorial scale experiments were performed to investigate and evaluate the performance and removal characteristics of organics, color, and genotoxicity by an integrated process including ozonation, activated carbon (AC), and biological aerated filter (BAF) for recycling biotreated dyeing wastewater (BTDW) collected from a cotton textile factory. Influent chemical oxygen demand (COD) in the range of 156 - 252 mg/L, 5-day biochemical oxygen demand (BOD5) of 13.5 - 21.7 mg/L, and color of 58 - 76° were observed during the 20-day continuous operation. Outflows with average COD of 43 mg/L, BOD5 of 6.6 mg/L, and color of 5.6° were obtained after being decontaminated by the hybrid system with ozone dosage of 0.25 mg O3applied/mg COD0, 40 min ozonation contact time, 30 min hydraulic retention time (HRT) for AC treatment, and 2.5 h HRT for BAF treatment. More than 82 % of the genotoxicity of BTDW was eliminated in the ozonation unit. The genotoxicity of the BAF effluent was less than 1.33 μg 4-nitroquinoline-N-oxide/L. Ozonation could change the organics molecular structures, destroy chromophores, increase the biodegradability, and obviously reduce the genotoxicity of BTDW. Results showed that the combined process could guarantee water reuse with high quality.

  18. Production of sorption functional media (SFM) from clinoptilolite tailings and its performance investigation in a biological aerated filter (BAF) reactor.

    Science.gov (United States)

    Feng, Yan; Qi, Jingyao; Chi, Liying; Wang, Dong; Wang, Zhaoyang; Li, Ke; Li, Xin

    2013-02-15

    The few reuse and large stockpile of zeolite tailings led to a series of social and environmental problems. This study investigated the possibility of using the zeolite tailings as one of principal raw materials to prepare sorption functional media (SFM) by a high temperature sintering process. The SFM was used to serve as a biomedium in a biological aerated filter (BAF) reactor for domestic wastewater treatment, and its purification performance was examined. The physical, chemical and sorption properties of SFM were also determined. The microstructure of the SFM was analyzed by scanning electron microscopy (SEM). Results revealed that: (1) zeolite tailings could be used to produce the SFM under the optimal sintering parameters; (2) the sorption and desorption isotherm of ammonia nitrogen on SFM could be well described by the Langmuir formula; (3) in terms of removing organic matter, ammonia nitrogen, turbidity and colourity, the performance of the biofilter with SFM was superior to that with haydite; and (4) SFM BAF has a stronger adaptability to low temperature (6-11°C) for NH(3)-N removal compared to haydite BAF. Therefore, the SFM produced from the zeolite tailings was suitable to serve as the biomedium in the domestic wastewater treatment.

  19. Production of sorption functional media (SFM) from clinoptilolite tailings and its performance investigation in a biological aerated filter (BAF) reactor

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yan [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); School of Civil Engineering and Architecture, University of Jinan, Jinan 250022 (China); Qi, Jingyao, E-mail: qjy_hit@yahoo.cn [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Chi, Liying [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Wang, Dong [School of Civil Engineering and Architecture, University of Jinan, Jinan 250022 (China); Wang, Zhaoyang; Li, Ke; Li, Xin [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2013-02-15

    Highlights: ► Sorption functional media (SFM) were prepared using zeolite tailings. ► Two upflow BAFs were applied to treat municipal wastewater. ► SFM BAF brought a relative superiority to haydite reactor. ► SFM BAF has a stronger adaptability to low temperature (6–11°C) for NH{sub 3}-N removal. ► The application provided a promising way in zeolite tailings utilization. -- Abstract: The few reuse and large stockpile of zeolite tailings led to a series of social and environmental problems. This study investigated the possibility of using the zeolite tailings as one of principal raw materials to prepare sorption functional media (SFM) by a high temperature sintering process. The SFM was used to serve as a biomedium in a biological aerated filter (BAF) reactor for domestic wastewater treatment, and its purification performance was examined. The physical, chemical and sorption properties of SFM were also determined. The microstructure of the SFM was analyzed by scanning electron microscopy (SEM). Results revealed that: (1) zeolite tailings could be used to produce the SFM under the optimal sintering parameters; (2) the sorption and desorption isotherm of ammonia nitrogen on SFM could be well described by the Langmuir formula; (3) in terms of removing organic matter, ammonia nitrogen, turbidity and colourity, the performance of the biofilter with SFM was superior to that with haydite; and (4) SFM BAF has a stronger adaptability to low temperature (6–11 °C) for NH{sub 3}-N removal compared to haydite BAF. Therefore, the SFM produced from the zeolite tailings was suitable to serve as the biomedium in the domestic wastewater treatment.

  20. Treatment of wastewater from an oil refinery sour water stripping unit using an aerated submerged biological filter

    Energy Technology Data Exchange (ETDEWEB)

    Ramaswamy, J.; Veenstra, J.N. [Oklahoma State Univ., Stillwater, OK (United States)

    1995-12-31

    The purpose of this research was to determine the kinetic constants for an Aerated Submerged Biological Filter (ASBF) used to reduce the toxicity of a petroleum refinery Process wastewater. The system was run at three different organic loadings and data were collected at steady state conditions for each loading. This data along with data obtained for three other loading conditions done a previous study (1) were used to determine the biokinetics constants which are required for the design of a full scale system. To measure the acute toxicity reduction, a 48- hour static bioassay was done on the ASBF unit influent and effluent. An attempt was also made to identify a significant fraction contributing to the toxicity by running the samples through a clinoptilolite column and then running a bioassay on the treated samples. At lower loading conditions (14.0 g COD/m{sup 2}/day), the ASBF gave maximum reduction of monitored parameters except ammonia. At the highest loading condition (24.0 COD/m{sup 2}/day), the reductions were smaller because the unit seemed to be operating near maximum organic loading capacity. Bioassays showed the LC{sub 50} generally increased after ASBF treatment, indicating toxicity reduction. The bioassays done on the samples treated by clinoptilolite showed further increase in the LC{sub 50} for the ASBF unit effluent indicating that ammonia may be a toxic fraction in the effluent. The kinetic constants were analyzed using the models proposed by Eckenfelder (2) and Korengay and Andrews (3). The proportionality constant for the former was equal to 0.00458 m{sup 3}/m{sup 2}/day. The area capacity constant for the latter was 22.8 g/m{sup 2}/day and the saturation constant 88.8 mg/{ell}. A model proposed by Kincannon and Stover (4) was also used to predict the kinetic constants. From this model the maximum specific substrate removal rate was determined to be 33.3 g/m{sup 2}/day and the proportionality constant was equal to 23.7 g/m{sup 2}/day.

  1. Advanced treatment of biologically pretreated coal gasification wastewater using a novel anoxic moving bed biofilm reactor (ANMBBR)-biological aerated filter (BAF) system.

    Science.gov (United States)

    Zhuang, Haifeng; Han, Hongjun; Jia, Shengyong; Zhao, Qian; Hou, Baolin

    2014-04-01

    A novel system integrating anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) with short-cut biological nitrogen removal (SBNR) process was investigated as advanced treatment of real biologically pretreated coal gasification wastewater (CGW). The results showed the system had efficient capacity of degradation of pollutants especially nitrogen removal. The best performance was obtained at hydraulic residence times of 12h and nitrite recycling ratios of 200%. The removal efficiencies of COD, total organic carbon, NH4(+)-N, total phenols and total nitrogen (TN) were 74.6%, 70.0%, 85.0%, 92.7% and 72.3%, the corresponding effluent concentrations were 35.1, 18.0, 4.8, 2.2 and 13.6mg/L, respectively. Compared with traditional A(2)/O process, the system had high performance of NH4(+)-N and TN removal, especially under the high toxic loading. Moreover, ANMBBR played a key role in eliminating toxicity and degrading refractory compounds, which was beneficial to improve biodegradability of raw wastewater for SBNR process.

  2. A field pilot-scale study of biological treatment of heavy oil-produced water by biological filter with airlift aeration and hydrolytic acidification system.

    Science.gov (United States)

    Zhang, Min; Wang, Junming; Zhang, Zhongzhi; Song, Zhaozheng; Zhang, Zhenjia; Zhang, Beiyu; Zhang, Guangqing; Wu, Wei-Min

    2016-03-01

    Heavy oil-produced water (HOPW) is a by-product during heavy oil exploitation and can cause serious environmental pollution if discharged without adequate treatment. Commercial biochemical treatment units are important parts of HOPW treatment processes, but many are not in stable operation because of the toxic and refractory substances, salt, present. Therefore, pilot-scale experiments were conducted to evaluate the performance of hydrolytic acidification-biological filter with airlift aeration (HA-BFAA), a novel HOPW treatment system. Four strains isolated from oily sludge were used for bioaugmentation to enhance the biodegradation of organic pollutants. The isolated bacteria were evaluated using 3-day biochemical oxygen demand, oil, dodecyl benzene sulfonic acid, and chemical oxygen demand (COD) removals as evaluation indices. Bioaugmentation enhanced the COD removal by 43.5 mg/L under a volume load of 0.249 kg COD/m(3) day and hydraulic retention time of 33.6 h. The effluent COD was 70.9 mg/L and the corresponding COD removal was 75.0 %. The optimum volumetric air-to-water ratio was below 10. The removal ratios of the total extractable organic pollutants, alkanes, and poly-aromatic hydrocarbons were 71.1, 94.4, and 94.0 %, respectively. Results demonstrated that HA-BFAA was an excellent HOPW treatment system.

  3. Treatment and re-use of urban sewage by means of aerated submerged biological filters and tertiary treatment; Depuracion y reutilizacion de las aguas residuales urbanas mediante filtros biologicos sumergidos aireados con tratamiento terciario

    Energy Technology Data Exchange (ETDEWEB)

    Mujal, F. J.

    2000-07-01

    The installations required for treating and re-using urban waste waters are reviewed. The treatment system put forward is called AERATED SURMERGED BIOLOGICAL FILTER AQUA PROCESS (S.B.F.). In this system, once that water has been clarified, it is treated biologically in an aerated reactor containing porous ceramic balls. After this it is filtered with silica+anthracite as a tertiary treatment. This technique minimize energy consumption and achieve optimum treatment performance at low running costs, as it requires little maintenance. Once the waste water has been treated in this way, the effluent is suitable for re-use to irrigate crops or infiltrate into underground aquifers. (Author)

  4. The Up-Flow Biological Aerated Filter (UFBAF) process in treating mixed (urban and industrial) sewage. Its performance in a pilot plant; Proceso de biofiltracion Up-Flow Biological Aerated Filter-UFBAF para el tratamiento de aguas residuales mixtas (urbanas e industriales). Rendimientos en planta piloto

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    The Up-Flow Biological Aerated Filter (UFBAF) process is a variant on the conventional activated sludge process. It is based on a greater sludge density, as the sludge sticks to expanded clay balls of between 3 and 6 mm in diameter. A trial of this process was conducted using a pilot plant whose main components were a bio filter for eliminating organic matter and a single layer filter for eliminating the solids left over from the bio filter. the effluent employed in the trial was waste water that had been pretreated by sieving and primary decanting. The main object of these trials was to determine the capacity and limits of the treatment in eliminating organic matter under overload conditions in order to determine the recovery time required to return to normal operation. (Author) 3 refs.

  5. Intermittent Aeration in Biological Treatment of Wastewater

    Directory of Open Access Journals (Sweden)

    H. Doan

    2009-01-01

    Full Text Available Problem statement: E-coating process is widely used to provide a protective coating layer on metal parts in the automotive and metal finishing industry. The wastewater from the coating process contains organic compounds that are used in the cleaning, pretreatment and coating steps. Organic pollutants can be removed biologically. In the aerobic biological treatment, water aeration accounts for a significant portion of the total operating cost of the treatment process. Intermittent aeration is thus of benefit since it would reduce the energy consumption in the wastewater treatment. In the present study, wastewater from an electro-coating process was treated biologically using a packed column as an aerator where the wastewater was aerated by a countercurrent air flow. The objective was to obtain an optimum aeration cycle. Approach: Intermittent aeration time was varied at different preset cycles. An operational optimum of the aeration time (or air-water contacting time in the column was determined from the BOD5 removal after a certain treatment period. For continuous aeration of the wastewater, the air-liquid contacting time in the column was 52 min for 24 h of treatment. A unit energy consumption for pumping liquid and air, which was defined as the energy consumption per percent BOD5 removed, was used as a criterion to determine the optimum contacting time. Results: Optimum air-liquid contacting times were found to be about 38, 26 and 22 min for the treatment times of 24, 48 and 72 h, consecutively. This indicates that 27-58% saving on the unit energy consumption can be achieved using intermittent aeration of the wastewater. On the basis of the overall BOD5 removal, 17% and 23% savings in energy were observed with the intermittent aeration as compared to the continuous aeration of the wastewater for 48 and 72 h. Conclusion: The results obtained indicate that an appropriate intermittent aeration cycle can bring about a substantial energy saving

  6. Process of nitrogen transformation and microbial community structure in the Fe(0)-carbon-based bio-carrier filled in biological aerated filter.

    Science.gov (United States)

    Deng, Shihai; Li, Desheng; Yang, Xue; Zhu, Shanbin; Li, Jinlong

    2016-04-01

    Nitrogen pollutants in low-organic carbon wastewater are difficult to biodegrade. Therefore, the Fe(0)-carbon-based bio-carrier (FCBC) was firstly used as hydrogen producer in a biological-aerated filter (BAF) to make up for the lack of organic carbon in biological nitrogen removal. Physical and chemical properties of FCBC were detected and compared in this study. The nitrogen removal rate for low COD/TN ratio wastewater, nitrogen transformation process, and microbial communities in the FCBC filled in BAF were investigated. Results showed that the nitrogen removal rates was 0.38-0.41 kg N m(-3) day(-1) in the FCBC filled BAF and reached 0.62 kg N m(-3) day(-1) within the filter depth of 60-80 cm, under the conditions of the dissolved oxygen 3.5 ± 0.2 mg L(-1) and the inlet pH 7.2 ± 0.1. Hydrogenophaga (using hydrogen as electron donor), Sphaerotilus (absorbing [Fe(3+)]), Nitrospira (nitrificaion), and Nitrosomonas (ammonia oxidation) were found to be the predominant genera in the reactor. The reaction schemes in the FCBC filled in BAF was calculated: hydrogen and [Fe(3+)] were produced by Fe(0)-C galvanic cells in the FCBC, ammonia was oxidized into nitrate by Nitrosomonas and Nitrospira genera, hydrogen was used as electron donors by Hydrogenophaga genus to reduce nitrate into N2, and [Fe(3+)] was partly absorbed by Sphaerotilus and diverted via sludge discharging.

  7. 运行方式对曝气生物滤池实现短程硝化的影响%Effect of Operational Modes on Shortcut Nitrification in Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    梅翔; 占晶; 谢玥; 蒋飞; 马耀进

    2011-01-01

    In order to investigate the effect of operational modes on shortcut nitrification in a biological aerated filter for treatment of ammonia nitrogen wastewater, three operational modes including continuous influent with alternating aeration, influent with aeration and no influent without aeration, and influent without aeration and no influent with aeration were carried out. Moreover, in the case of continuous influent with alternating aeration, the performances of the biological aerated filter were investigated at three time phase ratios of aeration to no aeration, which were 4:4,5:3 and 2 : 2 : 2 : 2. The experimental results show that the nitrite accumulation rate of more than 90% and the ammonia nitrogen removal rate of more than 70% can be achieved and maintained under the condition of continuous influent with alternating aeration, with influent ammonia nitrogen of 53 to 101 mg/L, temperature of 33 ℃ , HRT of 8 h, air to water ratio of 22.7 and aeration to no aeration ratio of 5 : 3. This research indicates that the biological aerated filter can realize shortcut nitrification with a higher ammonia nitrogen removal rate and a higher nitrite accumulation rate via controlling the operational modes.%为研究曝气生物滤池处理氨氮废水时运行方式对实现短程硝化的影响,进行了连续进水交替曝气、进水曝气停水停气和进水停气停水曝气3种运行方式试验,并考察了连续进水交替曝气条件下3种不同交替曝气时段分配比例,即曝气:停气分别为(4∶4)、(5∶3)、(2∶2∶2∶2)对系统运行效果的影响.结果表明,在连续进水交替曝气条件下,当进水氨氮为53 ~ 101 mg/L、温度为33℃、水力停留时间为8h、气水比为22.7、交替曝气时段分配比例为5:3时可实现并维持90%以上的亚硝酸盐氮积累率,此时对氨氮的去除率也在70%以上.研究表明,通过调控运行方式可较好地实现曝气生物滤池的短程硝化,并获得较高的氨

  8. Wastewater treatment efficiency of a multi-media biological aerated filter (MBAF) containing clinoptilolite and bioceramsite in a brick-wall embedded design.

    Science.gov (United States)

    Ji, Guodong; Tong, Jingjing; Tan, Yufei

    2011-01-01

    A multi-media biological aerated filter (MBAF) with clinoptilolite media was used to treat synthetic wastewater. Coal ash bioceramsite with supplemental metallic iron was added to the clinoptilolite media of MBAFs in a brick-wall embedded design. Performance parameters, such as hydraulic, organic, N and P loading capacity and microbial community composition were studied for different quantity of supplemental metallic iron contained in three MBAFs. The MBAFs with more metallic iron were found to have superior hydraulic and organic loading, and higher N and P capacities. COD, NH3-N and TP removal dropped by 7-10%, 6-7% and 4-5%, respectively, with when hydraulic loading was raised from 2.8 to 7.5 m3 m(-2) d(-1). NH3-N removal also decreased 8-9% when ammonia loading was elevated from 0.078 to 0.156 kg NH3-N m(-3) d(-1). Real-time PCR revealed a relatively stable bacterial community composed primarily of eubacteria that formed after an initial 120 d operational period. Doubling the amount of metallic iron in the bioceramsite media resulted in a twofold increase of eubacteria in the MBAF, but a decrease in the ratio of anaerobic ammonia-oxidizing bacteria to total bacteria.

  9. PHOSPHORUS REMOVAL BY BIOLOGICAL AERATED FILTER THROUGH THREE CHEMICAL METHODS%三种投加方式化学强化BAF除磷的试验研究

    Institute of Scientific and Technical Information of China (English)

    李欣; 马营营; 董文艺

    2011-01-01

    Two-stage biological aerated filter process had a better removal of organic matter and nitrogen, but phosphorus removal is not effective,chemically enhanced phosphorus removal method is often adopted to achieve the standards. For this, the paper studied the pre-dosing, synchronization,post-dosing (FeCl3) chemically enhanced the effect of BAF for phosphorus removal. The results showed that: the best was pre-dosing, synchronizationwas better than post-dosing, but pre-dosing and post-dosing needed sedimentation tank, so synchronization was also a good way to meet TP effluentstandards.%两级曝气生物滤池串联工艺对有机物和氮的去除效果较好,但除磷效果不理想,常采取化学强化除磷的方法来达到排放标准.分别研究了前置、同步、后置铁盐( FeCl3)化学强化BAF进行化学除磷的效果.结果表明,前置除磷效果最好,同步好于后置,但考虑到前置和后置都得增加沉淀池,所以同步强化也是一种较好的方法,能够使出水TP达标.

  10. 曝气生物滤池填料选择的试验研究%Experimental study on biological aerated filter media selection

    Institute of Scientific and Technical Information of China (English)

    张玉荣

    2014-01-01

    针对浊度以及悬浮物浓度较高的原水,将柱状炭和陶粒两种填料应用在曝气生物滤池中作为深度净水工艺的预处理的方法并对处理效果进行了比较和分析。试验表明:陶粒对原水中的有机物、NH4+-N、浊度等指标有较好的去除效果,而柱状炭不甚理想。%according to the turbidity and suspended solids concentration of high water, the columnar carbon and ceramic fillers are used in biological aerated filter as a preprocessing method of depth of water purification process, and the treatment effect are compared and analyzed. Experiments show that the ceramic has better re-moval effect of organics, NH4+ -N, turbidity and other indicators in raw water, and the columnar carbon is not ideal.

  11. Biodegradation behavior of natural organic matter (NOM) in a biological aerated filter (BAF) as a pretreatment for ultrafiltration (UF) of river water

    KAUST Repository

    Huang, Guocheng

    2011-04-15

    In this study, biodegradation of natural organic matter (NOM) in a biological aerated filter (BAF) as pretreatment of UF treating river water was investigated. Photometric measurement, three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy and liquid chromatography with online organic carbon detector (LC-OCD) were used to investigate the fate of NOM fractions in the BAF+UF process. Results showed that the BAF process could effectively remove particles and parts of dissolved organic matter, which led to a lower NOM loading in the UF system, but different NOM fractions showed different biodegradation potentials. Further biodegradation batch experiments confirmed this observation and identified that polysaccharides and proteins (quantified using photometric methods) contained a large proportion of readily biodegradable matter while humic substances were mainly composed of inert organic substances. According to EEM measurements, it is evident that protein-like substances were more readily eliminated by microorganisms than humic-like substances. LC-OCD data also supported the phenomena that the polysaccharides and large-size proteins were more degradable than humic substances. © 2011 Springer-Verlag.

  12. 曝气生物滤池处理石油采出水的动力学特性研究%Kinetic Performance of Oil-field Produced Water Treatment by Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    苏德林; 王建龙; 刘凯文; 周定

    2007-01-01

    The biological aerated filter (BAF) was used to treat the oil-field produced water. The removal efficiency for oil, COD, BOD and suspended solids (SS) was 76.3%-80.3%, 31.6%-57.9%, 86.3%-96.3% and 76.4%-82.7%, respectively when the hydraulic loading rates varied from 0.6m·h-1 to 1.4m·h-1. The greatest part of removal, for example more than 80% of COD removal, occurred on the top 100cm of the media in BAF. The kinetic performance of BAF indicated that the relationship of BOD removal efficiency with the hydraulic loading rates in biological aerated filters could be described by cr/ci=1-exp(-2.44/L0.59). This equation could be used to predict the BOD removal efficiency at different hydraulic loading rates.

  13. Advanced treatment of port cabin washing wastewater by integrated process ozonization-biological aerated filter-biological aerated filter%一体化O3-BAF—BAF组合工艺深度处理港口洗舱废水

    Institute of Scientific and Technical Information of China (English)

    葛启龙; 汪晓军

    2013-01-01

    采用一体化臭氧曝气生物滤池(O3-BAF)—曝气生物滤池(BAF)组合工艺对二级生化处理后的港口码头洗舱化学品废水进行深度处理,进水COD约为200~240 mg/L,色度为16~32倍时,经该工艺处理后出水COD<30mg/L,去除率>91%,色度降到4倍以下,出水水质达到《生活杂用水水质标准》(CJ/T48-1999)要求.工程运行实践表明,该深度处理系统运行稳定,处理效率高,具有良好的经济效益与环境效益.%The integrated ozonization-biological aerated filter-biological aerated filter combined process has been applied to the advanced treatment of port cabin washing wastewater after secondary biochemical treatment.When the COD of the influent is 200-240 mg/L,and chroma is 16-32 times,COD of effluent is reduced to less than 30 mg/L after treatment,the removing rate is more than 91%,and chroma is reduced to less than 4 times,reaching the specified Miscellaneous Domestic Water Quality Standard(CJ/T 48-1999).The result shows that the advanced treatment system runs stably,and has high treatment efficiency.It has great economic and environmental benefits.

  14. 陶粒-沸石-活性炭组合填料生物滤池的研究%Research on Ceramic-zeolite-active Carbon Combined Medium Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    张尊举; 董春艳

    2013-01-01

    采用陶粒、沸石、活性炭填料合理组合作为曝气生物滤池的填料对高校生活污水进行处理。研究了组合填料生物滤池生物膜的培养,不同水力负荷、容积负荷和气水比对污水处理效率的影响,以及该生物滤池对生活污水的处理效果。结果表明,采用组合填料生物滤池,接种挂膜培养周期为25 d,在水力负荷为2.5 m3/(m2·h),气水比3.5:1,组合填料生物滤池出水COD、 BOD5、 SS、 NH3-N和色度平均值达到《城市污水再生利用城市杂用水水质》GB/T 18920-2002水质要求。%As a filter medium, Ceramic, zeolite, activated carbon were combined to use for biological aerated filter in the treatment of campus domestic wastewater. The study focused on the start rule of the combined medium biological aerated filter. Meanwhile, different hydraulic load, load capacity and water ratio on the sewage treatment effect, and the treatment effect of biological aerated filter for domestic wastewater were studied. The results show that, the time needed for the start-up and film formation of combined medium biological aerated filter about 25 d. When the hydraulic load was 2.5 m3/(m2·h) , the water ratio was 3.5:1, combined medium biological aerated filter becomes more reasonable and suitable, achieving good results in practical operation. the average values of COD、 BOD5、 SS、 NH3-N and Chrominance reached the Standards for The reuse of urban recycling water-water quality standard for urban miscellaneous water consumption GB/T 18920-2002.

  15. The use of bottle caps as submerged aerated filter medium.

    Science.gov (United States)

    Damasceno de Oliveira, Laurence; Motlagh, Amir Mohaghegh; Goel, Ramesh; de Souza Missagia, Beatriz; Alves de Abreu Filho, Benício; Lautenschlager, Sandro Rogério

    2014-01-01

    In this study, a submerged aerated filter (SAF) using bottle caps as a support medium was evaluated. The system was fed with effluent from an upflow anaerobic sludge blanket system at ETE 2-South wastewater treatment plant, under different volumetric organic load rates (VOLRs). The population of a particular nitrifying microbial community was assessed by fluorescent in situ hybridization with specific oligonucleotide probes. The system showed an average removal of chemical oxygen demand (COD) equal to 76% for VOLRs between 2.6 and 13.6 kg COD m(-3)_media.day(-1). The process of nitrification in conjunction with the removal of organic matter was observed from applying VOLRs lower than 5.5 kg COD m(-3)_media.day(-1) resulting in 78% conversion of NH4(+)-N. As the applied organic load was reduced, an increase in the nitrifying bacteria population was observed compared with total 4'-6-diamidino-2-phenylindole (DAPI) stained cells. Generally, SAF using bottle caps as a biological aerated filter medium treating wastewater from an anaerobic system showed promising removal of chemical oxygen demand (COD) and conversion of NH4(+)-N.

  16. Backwashing of upflow biological aerated filter%上向流曝气生物滤池反冲洗实验研究

    Institute of Scientific and Technical Information of China (English)

    邱立平; 王广伟; 张守彬; 陈京英; 刘永正

    2011-01-01

    In order to get deeper understanding of the relationship between headloss development and back-washing in biological aerated filters (BAFs) , backwashing procedure which employed air washing, water washing and water rinse process was optimized in three BAFs with zeolite, ceramic particle and carbonate media respectively, and the recovery of headloss and treatment efficiency in biofilter after backwashing were also investigated based on the theoretical analysis. The results showed that the initial COD and SS concentration in effluent increased after backwashing but recovered in 2 hours. The ammonia nitrogen concentration in effluent almost did not change and recover quickly. All three BAFs have a promising treatment performance and operational stability after backwashing. The backwashing procedure of upflow BAF is suggested as follows; firstly, air washing 2 ~ 3 min with flow rate of 10 L/( m2 · S) , then air and water washing 3 ~ 5 min with both air and water flow rate of 10 L/(m2 · S) , finally, water rinse for 9 ~ 11 min with water flow rate of 10 L/( m2 · S).%为进一步探讨水头损失、反冲洗条件及反冲洗效果之间的关系,在前期理论分析的基础上,对天然斜发沸石、页岩陶粒和石灰岩碎石填料等3座曝气生物滤池的水洗、气洗和水漂洗等基本反冲洗过程进行了优化研究,考察了反冲洗后滤池水头损失的恢复情况以及反冲洗对处理效能的影响。结果表明,反冲洗后初滤出水的COD和SS稍有增加,但很快就在2 h内恢复正常,出水氨氮浓度的变化幅度最小,而且恢复速度更快。3种填料曝气生物滤池不仅表现出良好的处理效能和稳定的运行效果,对反冲洗过程的反馈也没有显著差异。建议上向流曝气生物滤池的反冲洗推荐程序为:先以气冲洗强度10 L/(m2·s)单独气洗2~3 min,再气水冲洗强度10 L/(m2·s)和水冲洗强度10L/(m2·s)联合反冲洗3~5min

  17. Study on Effect of Phosphorus Removal by Biological Aerated Filter Process%曝气生物滤池工艺除磷效果研究

    Institute of Scientific and Technical Information of China (English)

    王平; 张彩庆

    2011-01-01

    针对某电厂中水回用过程中的再生水深度处理工艺的选择,通过试验研究,分析了曝气生物处理工艺对废水的除磷效果,可为电厂设计和其它工程的实施提供参考和借鉴。%Aiming at the selection of advanced treatment in reclaimed water reuse for a power plant,to analyze the effect of aeration biological process on phosphorus removal from wastewater through experimental study,so as to provide re-ference for power plant design and other projects.

  18. Admissible loads in wastewater treatment, using a recycled support materials in a biological aerated filter; Cargas admisibles en depuracion de aguas residuales, usando material reciclado como soporte de un filtro sumergido

    Energy Technology Data Exchange (ETDEWEB)

    Osorio Robles, F. [E.T.S.I. de Caminos Canales y Puertos de Granada (Spain)

    2000-07-01

    This study places in the context of the research into Biological Aerated Filters that the Environmental Technology and Environmental Microbiology Research Group (University of Granada, Spain) has been developing for several years. We have achieved a high level of optimization of the system, using a recycled ceramic-based materials as biofilm support. It enables to give some design parameters, which will make possible the practical application in the future. In this article the relations among volumetric and hydraulic loads applied and effluent concentrations and elimination rates in relation to several pollutants are presented. The oxygen supplied has been accurately controlled, and the relation among the consumption value and the loads applied and the system efficiency obtained is presented. The tests were performed at a pilot plant with full scale height. The influent used was the primary effluent of a conventional treatment plant and the operational flow was counter-current flow. (Author) 11 refs.

  19. Integrated Technology of Ozone Catalysis Oxidation -Modified Biological Aeration Filter -Ultrafiltration and Reverse Osmosis for Deep Treatment of Coking-Plant Wastewater%臭氧催化氧化-MBAF-UF-RO处理焦化废水

    Institute of Scientific and Technical Information of China (English)

    文志军; 赵爱国; 郎晓政

    2014-01-01

    China Energy Conservation and Reduction Co., LTD Construct the wastewatert reatment plant for a coking –plant by BT mode. Through analysis and argumentation, the main treatment process is a integrated technology of ozone catalysis oxidation – modified biological aeration filter – ultrafiltration and reverse os⁃mosis. The result shows that the treated water of water treatment system can meet the requirement of make-up water requirement, and the ozone catalytic oxidation reactor makes effective degradation of small molecule organic matter, at the same time, it can effectively improve the biodegradability of wastewater, which is subse⁃quent for the aeration biological filter (MBAF) and the deep desalting system (UF + RO).%中国节能减排有限公司以BT模式承建焦化废水深度处理工程。经过分析和论证,确定以臭氧催化氧化反应器+MBAF反应器+UF+RO作为水处理主体工艺。项目建成后,系统出水水质优于循环冷却补给水要求,特别是臭氧催化氧化反应器在降解小分子有机物的同时,有效改善废水可生化性,为后续改良曝气生物滤池(MBAF)进一步生物降解有机物提供了有利条件,从而确保深度脱盐系统(UF+RO)的高效、稳定运行。

  20. 曝气生物滤池处理腈纶废水的启动性能研究%Research on the Start-up Performance of the Biological Aerated Filter for Treating Acrylic Water

    Institute of Scientific and Technical Information of China (English)

    卞吉良; 张洪林; 李长波; 马会强

    2011-01-01

    A bench scale experimental BAF was established, with which acrylic waste water was treated. The start-up law of BAF in treating the waste water containing acrylic was studied. Ceramsite was used as the filter in BAF. Under the conditions of the flow of 2SL/h, aeration rate of 40L/h, the removal rate of COD and ammonia was tested every day. The results demonstrated that the removal rate of COD was about 65% after 15 days; and the removal rate of ammonia was about 60% after 18 days. The result of the optical bio-microscope observation showed that the ecosystem with many kinds of different microbes and distinct biological phase distribution was formed in the BAF. Therefore, the course of biofilm formation and the degree of biological nitrification could be estimated by the change of removal rate of ammonia and COD during the course of the natural start-up of the BAF.%以曝气生物滤池(Biological Aerated Filter,BAF)净化腈纶废水为研究对象,研究了BAF处理腈纶废水的启动规律.试验以陶粒为滤料,在流量为25Lh,曝气量为40L/h的试验条件下,每天测试COD和氨氮的去除率变化情况.BAF对COD,氨氮有一定的去除效果.启动15d后,COD去除率达到65%;18d后,氨氮去除率达到60%以上.镜检表明,填料表面生物膜中均存在着多种微生物和明显的生物相分布.BAF挂膜过程中可以通过氨氮和COD去除率变化,来判断填料挂膜的进程和生物硝化作用进行的程度.

  1. Application of Biological Aerated Filter in Municipal Wastewater Treatment Plant%曝气生物滤池在城镇污水处理厂中的应用

    Institute of Scientific and Technical Information of China (English)

    冯亚兵; 季叶飞

    2013-01-01

    苏南某城镇污水处理厂采用曝气生物滤池工艺,出水执行GB 18918-2002《城镇污水厂污染物排放标准》中一级A标准.介绍了工艺流程以及各处理单元设计参数,并对设计过程中着重考虑的问题以及调试运行情况进行了说明.%Biological aerated filter process is used in a municipal wastewater treatment plant in the south of Jiangsu Province. The effluent quality implements the first-grade A standard of "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918—2002)". The process of the plant and the design parameters for every disposal unit were introduced, the problems emphatically considered in the design procedure and the commissioning operation were also explained.

  2. 改性粉煤灰与厌氧-曝气生物滤池联合处理印染废水%The Treatment of Dyeing Wastewater With Fly Ash Modified Biological Aerated Filter Coupling

    Institute of Scientific and Technical Information of China (English)

    贾艳萍; 宗庆; 姜修平; 张羽汐; 袁志峰

    2014-01-01

    印染废水具有成分复杂、色度大、有机物含量高、水质变化大等特点,属于难生物降解工业废水。采用盐酸改性粉煤灰预处理与厌氧-曝气生物滤池( AF-BAF)联合工艺处理模拟印染废水,考察温度、pH、曝气量和HRT等因素对脱色率以及COD、NH+4-N、NO-3-N和NO-2-N去除率的影响。研究结果表明:在温度10℃,pH为10,曝气量为50 L/h,HRT为4 h,改性粉煤灰粒度为100~120目的条件下, COD、NH+4-N、NO-3-N和NO-2-N去除率分别为72%、58%、78%和52%,脱色率为90%,达到了国家工业废水排放标准。改性粉煤灰提高了AF-BAF对印染废水的脱色效果,同时对COD、NH+4-N、NO-3-N、NO-2-N的去除具有促进作用。%Dyeing wastewater,difficult to be biodegraded,is characterized by complicated component,dark col-ority,high concentration,water quality fluctuation,etc. Modified filter pretreatment of fly ash and anaerobic fil-ter-biological aerated filter(AF-BAF) is adopted to treat the dyeing wastewater to study the impacts of the facts such as temperature,pH,aeration,and HRT,etc on discoloration rate and the removal efficiency of COD、NH+4-N、NO-3-N and NO-2-N. The results showed that the removal efficiency of COD,NH+4-N,NO-3-N,and NO-2-N were 72%, 58%, 78%, and 52%, respectively under the condition of temperature 10 ℃, pH10 , aeration rate 50L/h,HRT 4h and the modified fly ash particle size was 100-120 mesh condition,the decolori-zation rate was 90%,reaching the national drainage standard for industrial waste water. The modified fly ash improved the decolorization of dyeing wastewater by AF-BAF,and promoted the removal of NH+4-N,NO-3-N, NO-2-N.

  3. 曝气生物滤池对邻苯二甲酸二己酯的生物降解试验%Experiment on biodegradation of dihexyl phthalate by biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    赵晶; 余健; 李伟; 宋又群

    2012-01-01

    The present paper is aimed at introducing our study on the biodegradation features and relevant influencing factors of the biological aerated filter (BAF) for dihexyl phthalate (DHP) removal so as to find a new approach to pollution control of phthalic acid esters (PAEs). As is known, PAEs are a kind of environmental hormones which become widespread in our water environment and they have been in turn paid more and more attention to due to their teratogenici-ty, mutagenicity and carcinogenicity. DHP is one of the PAEs used widely for manufacturing plastics but contributes to the environmental pollution. Therefore, it is necessary for DHP to get biodegradated so as to remove and reduce its toxicity. It is for this purpose, ceramsite medium biological aerated filter (BAF) has been used to treat the sewage containing DHP. It is also for this purpose of the treatment efficiency that we have done investigations of the optimal temperatures in different empty bed contact time and analyzed the major intermediate products of biodegradation of DHP via GC - MS. The results of our investigation indicate that we have succeeded in increasing the removal rate of DHP to 95.5% under the conditions of 25 t and 8 hours of the empty bed contact time. We have also found that it is E-BCT that plays the main role between the two influential factors of the removal effect. At the lower-middle layer of the filter bed, DHP is more efficient in doing the biodegradation because there exists higher concentration of organic compounds and active microbes. However, things are just going on the contrary with the upper-middle layer in the filter bed. The major intermediate products of bio-degradation of DHP are made up of dibutyl phthalate ( DBP), monobutyl phthalate (MBP), dimethyl phthalate (DMP) and phthalic acid (PA). It is for this need, we have first of all cleavaged the long chain of the alcoholic ending of DHP into shorter and more straight ones by cleavaging one of the two ester bonds, and

  4. Towards integrated operation of membrane bioreactors: effects of aeration on biological and filtration performance.

    Science.gov (United States)

    Dalmau, M; Monclús, H; Gabarrón, S; Rodriguez-Roda, I; Comas, J

    2014-11-01

    Two experimental studies evaluated the effect of aerobic and membrane aeration changes on sludge properties, biological nutrient removal and filtration processes in a pilot plant membrane bioreactor. The optimal operating conditions were found at an aerobic dissolved oxygen set-point (DO) of 0.5 mg O2 L(-1) and a membrane specific aeration demand (SADm) of 1 m h(-1), where membrane aeration can be used for nitrification. Under these conditions, a total flow reduction of 42% was achieved (75% energy reduction) without compromising nutrient removal efficiencies, maintaining sludge characteristics and controlled filtration. Below these optimal operating conditions, the nutrient removal efficiency was reduced, increasing 20% for soluble microbial products, 14% for capillarity suction time and reducing a 15% for filterability. Below this DO set-point, fouling increased with a transmembrane pressure 75% higher. SADm below 1 m h(-1) doubled the values of transmembrane pressure, without recovery after achieving the initial conditions.

  5. UASB-A/O-曝气生物滤池工艺处理聚丙烯酰胺废水%UASB-A/O-Biological Aerated Filter Process Treat Acryl Amide Production Wastewater

    Institute of Scientific and Technical Information of China (English)

    李本勇

    2013-01-01

    The asylums wastewater was treated with UASB-A/O-Biological aerated filter ,the quan-tity of wastewater is 120 m3/d .When the quality concentrations of COD ,BOD5 ,SS ,NH3-N in influent are 4140 ,1420 ,238 ,78 mg/l ,the quality concentrations of COD ,BOD5 ,SS ,N H3-N in effluent are 112 , 17 ,13 ,11 mg/l ,respectively ,which reach the second-class standard of the compensative sewage dis-charge standard .It has been proved by practice that the combined technique has strongpoint such as low investment ,little area ,steady operation effect ,low operation cost and recycled resources .%  UASB-A/O -曝气生物滤池组合工艺处理聚丙烯酰胺高浓度有机废水,设计规模为120m3/d。在进水COD、BOD、SS、NH3-N的质量浓度分别为4140、1420、238、78mg/l时,处理后出水COD、BOD、SS、NH3-N的质量浓度分别为112、17、13、11mg/l ,达到污水综合排放标准(GB 8978–1996)二级标准。工程实践表明,该组合工艺具有投资少,占地面积小、运行效果稳定、运行费用低等优点。

  6. 曝气生物滤池不同水质挂膜的实验研究%The experimental study on biofilm growing of Biological Aerated Filter with different raw water

    Institute of Scientific and Technical Information of China (English)

    宁艳春; 段巧丽; 蒲文晶; 钟大辉; 庄立波; 杜再江

    2011-01-01

    Appropriate biofilm growing method has the important meaning to fast start-up and the steady operation of the Biological Aerated Filter(BAF). The tests were compared by the different raw water conditions and different start-up methods. Mainly through COD removal rate,as well as contras-test analysis of the biofacies microscopic exam of the biofilm on the media of BAFs,found the appro-priate start-up method for the secondary clarifier effluent of sewage factory. The test results indicated that the start-up by the mixed sewage and the sanitary sewage is quicker than by the secondary clarifi-er effluent. But the biofilm formed by the secondary clarifier effluent is more stable with effective op-eration. This is more appropriate in the actual movement.%合适的挂膜方法对曝气生物滤池的快速启动和稳定运行具有重要意义.开展了不同原水条件下的挂膜启动和不同挂膜方法的对比实验.主要通过滤柱对COD指标的去除情况,以及滤料上生物膜的生物相镜检对比分析,找到适合处理污水厂二级出水的挂膜启动方法.实验结果表明,使用污水厂混合进水和生活污水启动挂膜速度要明显优于采用二沉池出水启动挂膜,但采用二沉池出水启动挂膜后滤料表面生物膜更稳定,在实际运行中更加合适.

  7. 上向流曝气生物滤池水头损失沿程分布与动态特性%Headloss profile and dynamic characteristics in upflow biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    邱立平; 王广伟; 张守彬; 陈京英; 刘永正

    2011-01-01

    对比考察了天然斜发沸石、页岩陶粒和石灰岩碎石填料曝气生物滤池的水头损失增长规律,分析了3种滤池水头损失的空间分布特征和动态变化特性,探讨了截留固体累积量对水头损失发展的影响规律。结果表明,沸石、陶粒和石灰岩曝气生物滤池均具有较好的有机物和SS沿程去除能力,并与水头损失的沿程分布密切相关;滤池内部TSS的沿程变化趋势和水头损失沿程分布趋势基本一致;曝气生物滤池的水头损失随着反应器运行时间的延长而缓慢增加,当滤床内TSS积累量增加到一定程度时,气体的滤床驻留率增加,并与TSS积累协同作用,滤床局部孔隙率迅速下降,水头损失迅速越升。曝气生物滤池的反冲洗首先应着眼于解决滤床的局部孔隙率过低问题,然后以气洗促进颗粒碰撞,气水联合提高剪切力,最后水漂洗排出TSS和气泡。%Headloss development in three biological aerated filters with zeolite,ceramic particle and carbonate,respectively,were investigated in this paper.The profile and dynamic characteristics of headloss development and the influence of solid accumulation on the headloss development were also considered.Promising COD and SS removal performance were observed in the three filters,and that were relevant to the headloss profile.The variation tendency of TSS in the filter was also in accord with that of headloss profile.The headloss in BAF increased slowly with filter operation.The gas holdup in the filter bed increased with TSS increasing and could accelerate the headloss development.When TSS increased to a certain extent,the gas holdup increased quickly,porosity ratio of filter bed decreased and headloss ascended suddenly.It was suggested that the backwashing of BAF should be carried out to recover bed porosity ratio in some location firstly.The gas washing could promote the collision of granular media,and then to enhance the shearing force by gas

  8. 适宜填料提高温室甲鱼养殖废水曝气生物滤池处理效能%Suitable substrates to improve efficiency of biological aerated filter for greenhouse turtle breeding wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    陈重军; 张蕊; 王亮; 吴伟祥; 陈英旭

    2013-01-01

    The greenhouse turtle breeding wastewater contains high concentration of nitrogen and phosphorous. Its unordered discharge has seriously affected the quality and safety of daily and production water supply of the surrounding residents. The greenhouse turtle breeding wastewater has become one of the main pollution sources in the rural area of the Yangtze River Delta, especially in the compact district of turtle aquaculture. In order to provide some experiences for the practical application in a turtle aquaculture farm, the experiment would explore the feasibility of a biological aerated filter (BAF) for greenhouse turtle breeding wastewater treatment, and select a suitable substrate for the BAF. In this paper, we have investigated three types of substrates filling in the BAF, i.e. clinoptilolite, bio-ceramic and gravel, in terms of their capacity of adsorbing the nitrogen and phosphorous in the greenhouse turtle breeding wastewater, and the performance of purifying wastewater. The results have showed that the nitrogen adsorption capacities in the three substrates are similar in the range of 0.469-0.563 mg/g, but that the phosphorous adsorption capacity greatly varies from 0.003 to 0.114 mg/g with the best one from the clinoptilolite. A pilot scale of BAF for greenhouse turtle breeding wastewater treatment was built in one of the typical greenhouse turtle aquaculture farms in the Yangtze River Delta. After 122 days running in the BAF with different influent concentration, the results showed that the BAF with clinoptilolite, bio-ceramic and gravel substrate have good removal efficiency for COD, NH4+-N, TN, TP and so on. The result of pilot engineering has showed that average COD, NH4+-N, TN and TP removal efficiencies of a biological aerated filter are 59.4%-61.1%,93.2%-97.2%,54.4%-71.1%and 62.7%-84.3%, respectively. The clinoptilolite filter excels in the removal of total nitrogen (TN) compared to the others, whereas the bio-ceramic and the gravel filters have the

  9. Study on Pretreatment of Contaminated Raw Water by the Lava-based Biological Aerated Filter%火山岩BAF预处理污染水源的研究

    Institute of Scientific and Technical Information of China (English)

    陈玮; 田孝禾; 邢岚英; 刘宏远

    2016-01-01

    The efficiency of pretreatment of contaminated raw water by biological aerated filter, which based on the lava rock, was studied in this paper. The results indicated that BAF was effectually purged the contaminant in the raw water under the condition of the air/water ratio at 1∶1;the influent flow was 50 L/h, filtering velocity at 6.4 m/h. During the normal temperature period (11.9~32.9℃), the average removal rate of ammonia, nitrite nitrogen and CODMn were 92.76%, 94.46%and 30.69%, respectively. And during the low temperature period (5.1~10.8℃), the average removal rate of ammonia, nitrite nitrogen and CODMn were 85.82%, 48.42%and 24.15%, respectively. In the whole experiment period, the average removal rate of turbidity and UV254 were 45.68%, 45.68%. BAF, as a pretreatment process, can efficiently remove pollutants, such as ammonia, organic matters, etc.%采用火山岩为填料的曝气生物滤池(BAF)进行了预处理污染水源的试验研究。试验结果表明,在气水比为1∶1,流量为50 L/h,滤速6.4 m/h的条件下,火山岩BAF能有效净化水中的污染物质。其中常温期(11.9~32.9℃),氨氮、亚硝氮和CODMn的平均去除率分别为92.76%、94.46%和30.69%;低温期(5.1~10.8℃),氨氮、亚硝氮和CODMn的平均去除率分别为85.82%、48.42%和24.15%;试验期间对UV254和浊度的平均去除率分别为7.29%,45.68%。因此,火山岩BAF作为预处理工艺能有效去除原水中的氨氮和有机物等污染物。

  10. A study on transformation of main pollutants along the wastewater flow in biological aerated filter%海水曝气生物滤器污染物沿程转化规律的研究

    Institute of Scientific and Technical Information of China (English)

    张延青; 陈江萍; 沈加正; 侯沙沙; 刘杨; 刘鹰

    2011-01-01

    The performances of biological aerated filter (BAF) with hollow bamboo balls as filter media for wastewater treatment in marine aquaculture was investigated. The wastewater was conditioned at pH ranging from 7.8-8.0, DO ranging from 2.8~5.8mg/L, air-to-water ratio at 3, hydraulic load of 0.58m3/(m3h), TAN load of 0.35~0.46g/(m3·h), and organic load of 1.58g/(m3h). Transformation of organic substances and ammonia nitrogen along the water flow were evaluated to determine the spatial distribution characteristics of pollutants. Results showed that most CODMn was removed between 0-10cm height, with 49.12% CODmn removed and 34.88% soluble CODMn removed in this range, meanwhile most TAN removed between 0-30cm height, with 18% TAN removed at 10cm and 55% removed at 30cm. The biomass and microbial activity decreased from the bottom of the filter to the top. In conclusion, pollutants were mainly removed between the height of 0~30cm, and the left section of the filter always acted as a buffer to remove pollutants remained in the wastewater, in case of sudden waste load or hydraulic impact.%以竹制空心生化球填料生物滤器处理海水养殖废水为对象,在水力负荷为0.58m3/[m3(填料)·h]、氨氮负荷为(0.35~046)g/[m3(填料)·h]、有机负荷约为11.58g/[m3(填料)·h]、气水比3∶1、pH值为7.8~8.0、DO浓度2.8~5.8mg/L的条件下,考察了有机物和总氨氮(TAN)的沿程转化规律,分析了污染物的空间分布特性.结果表明:在给定的运行条件下,CODMn的主要去除区间在滤器的0~10cm高度,其中CODMn和溶解性CODMn在此处的去除率分别为49.12%和34.88%;TAN的主要去除区间为0~30cm,其中10cm处TAN的去除率为18%,30cm处为55%;生物量和生物活性由下向上呈递减的分布趋势;生物滤器污染物的主要去除区间为0~30cn,受到水质、水量冲击时,较高层的填料(30~60cm)起到了缓冲作用,将下层生物膜未能降解的污染物去除.

  11. 曝气生物滤池中无机氮转化规律与降解数学模型%Transformation Regularity of Inorganic Nitrogen and Mathematical Model of Degradation in Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    夏绍凤

    2012-01-01

    Biological aerated filter (BAF) reactor in which the sewage and gas flow upward through the filtering media layer is one of the pushing reactors. In order to study its characteristics of inorganic nitrogen transformation along the reactor, the reactor was divided into four sampling sites and the different characteristics of inorganic nitrogen transformation caused by different organic loading and NH3-N loading as well as the biological quantity and activity of each section was researched. The result indicates when hydraulic loading rate is 1.13-2.38 m3/m2+h, ratio of air and water is 4-5:1, DO is 2.9-5.9 mg/L and NH3-N loading is 0.25-0.5 kgNH3-N/m3+d without any organic carbon, the major reaction is nitration in the reactor. More than 70 % NH3-N in the influent is nitrified when the relative height of the filter is less than 0.52. Total nitrogen (TN) basically maintains balanced, NO-3 -N increases, and there is few NOj -N in the reactor. According to Eckenfelder model, the kinetics equation of NH3-N transformation is Se = 50exp(-0.013 4D/L1.261 2).%上向流曝气生物滤池反应器(BAF)中的污水、空气从下往上同向流过滤料层,是一种推流式反应器.为研究其沿程无机氮转化特性,试验装置由下至上共设有4个取样口,研究各区间段由于NH3-N负荷、生物数量及活性等不同引起的沿程无机氮转化特性差异.试验结果表明在水力负荷为1.13~2.38 m3/m2·h、气水比为4~5∶1、沿程DO为2.9~5.9 mg/L、NH3-N负荷为0.25~0.5 kgNH3-N/m3·d、不加任何有机碳源的情况下,反应器内以硝化反应为主,进水中70%以上的NH3-N在相对高度0.52以下部分被硝化.曝气生物滤池沿程NO3- -N增加,NO2--N含量较少,TN基本维持平衡.依据Eckenfelder模式,BAF滤池中NH3-N沿程转化动力学方程为:Se=Soexp(-0.013 4D/L1.2612).

  12. 不同曝气位置曝气生物滤池(BAF)处理对虾养殖污水的试验研究%Biological Aerated Filters of Different Aeration Locations for Wastewater Treatment During Litopenaeus vannamei Culture

    Institute of Scientific and Technical Information of China (English)

    陈强; 黎中宝; 张艳艳; 王晨晨; 王超; 于凌宇

    2012-01-01

    采用不同曝气位置的上向流生物滤池处理对虾养殖污水,连续运行30 d,分析出水水质,并观察系统运行情况和装置污染状况.考察了对虾养殖污水中化学需氧量、氨氮、硝酸盐氮、亚硝酸盐氮、无机氮及活性磷酸盐6项指标的去除效果.结果表明:从养殖污水主要污染物指标的去除效果上看,中下部曝气生物滤池(MUBAF)要优于底部曝气生物滤池(BUBAF).在系统进水化学需氧量质量浓度为7.62~8.20 mg· L-1,氨氮质量浓度为0.62~0.65 mg·L-1,硝酸盐氮质量浓度为0.54~0.59 mg·L-1,亚硝酸盐氮质量浓度为0.23~0.27 mg· L-1,无机氮质量浓度为1.40~1.47 mg·L-1,活性磷酸盐质量浓度为0.24~0.29 mg·L-1,水温为25℃~30 ℃时,中下部曝气生物滤池对养殖污水中6项指标的去除率分别为45.2%、88.9%、58.5%、78.8%、75.3%和25.1%.可见,对氨氮的去除效果最佳,亚硝酸盐氮和无机氮次之,化学需氧量和硝酸盐氮的去除效果较差,活性磷酸盐去除率最低.总体而言,曝气生物滤池在水产养殖污水应用中处理效果明显,具有可行性和实用性.%In this paper, the up-flow biological aerated filter of middle aeration Location( MUBAF) and up-flow biological aerated filter of bottom aeration Location( BUBAF) were adopted to treat aquacultural wastewater of Litopenaeus vannamei. The water quality indexes such as chemical oxygen demand(COD), ammonia nitrogen(NH3-N), nitrate nitrogen(NO3-N), nitrite nitrogen(NOi-N), inorganic nitrogen (DIN) and soluble reactive phosphates( P04-P) were measured and analysed during 30 days processing. The study focused on the effect of the purification characteristics for aquacultural wastewater. Both the operating condition and the polluted condition of the wastewater treatment were also observed. The results showed that the removal rates of pollutants above using MUBAF were superior than that using BUBAF. When the temperature was

  13. 两段错向流曝气生物滤池处理生活污水%Two-sect Up and Down Flow Biological Aerated Filter for Domestic Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    司马卫平; 董建威

    2011-01-01

    采用半柔性填料和酶促好氧填料的两段错向流曝气生物滤池(TUDBAF)处理生活污水,考察了试验启动阶段水力停留时间对SS、COD和NH3-N的去除效果的影响,并分析了反冲洗对BAFU段生物膜活性的影响.结果表明:在水力停留时间6.5~13.0 h条件下,SS 和COD的去除率随水力停留时间的增加而增大,且其去除率分别达91.6%和83.6%以上;反应器对氨氮的去除主要集中在BAFU段,该段对氨氮的去除占总去除率的70%以上;BAFU段采用气水联合反冲洗过程中可以出水TSS浓度(708mg/L)作为该段反冲洗的终点.%A two-sect up and down flow biological aerated filter (TUDBAF) with semi-soft media and enzyme-enhanced aerobiosis biofilling was used to treat domestic wastewater. Influence of HRT on SS, COD and NH3-N removal efficiency was investigated. Also the influence of backwash on the activity of biofilms was analyzed. Experimental results showed that under HRT of 6.5~13.0h, removal rates of SS and COD both increased with the increasing HRT and that both removal rates of which was above 91.6% and 83.6% respectively. It also indicated that removal of NH3-N mainly concentrated in BAF U and that of NH3-N in BAF U was over 70% of total removal rate. Effluent concentration of TSS of 708mg/L in BAF U using of air and water backwash process can serve as the end of backwash.

  14. 新型曝气生物滤池处理生活污水试验研究%Experimental Study on New-type Biological Aerated Filter for Domestic Sewage Treatment

    Institute of Scientific and Technical Information of China (English)

    司马卫平; 何强; 张玉平

    2012-01-01

    采用半柔性填料和酶促好氧填料的两段上向流曝气生物滤池(TUBAF)处理生活污水,考察了氨氮容积负荷和溶解氧对其处理效能的影响,并分析了BAF C段有机物的去除对BAFN段处理效果的影响.结果表明,在氨氮容积负荷为0.05 ~0.25 kg/( m3·d)的条件下,对氨氮的去除率为83.2% ~94.1%;BAF C段和BAF N段的最佳DO浓度分别为(2.0 ~3.0)和(3.0 ~5.0)mg/L,能够有效实现有机物和氨氮的去除;BAF C段对有机物的去除为BAF N段对氨氮的去除提供了较好的外部环境,成功地实现了BAF N段的硝化分区.%A two-stage up-flow biological aerated filter (TUBAF) with semi-soft media and enzyme-catalyzed aerobic media ( denoted by BAF-C and BAF-N respectively) was used to treat domestic sewage. The influence of ammonia nitrogen volumetric loading and dissolved oxygen concentration on the pollutant removal efficiency was investigated, and the contribution of the removal of organic matter in BAF-C to the treatment efficiency in BAF-N was analyzed. The experimental results showed that when the ammonia nitrogen volumetric loading was 0. 05 to 0. 25 kg/( m · d) , the removal rate of ammonia nitrogen was 83. 2% to 94. 1% . The organic matter and ammonia nitrogen could be effectively removed when dissolved oxygen concentrations in BAF-C and BAF-N were 2. 0 to 3.0 mg/L and 3.0 to 5. 0 mg/L respectively. The removal of organic matter in BAF-C provided a better external environment for the removal of ammonia nitrogen in BAF-N, and the nitrification in BAF-N was realized successfully.

  15. 陶粒-海绵铁混合填料BAF深度处理酱油废水研究%Study of Biological Aerated Filter for Sauce Wastewater Advanced Treatment with Spongy Iron and Argil Granules

    Institute of Scientific and Technical Information of China (English)

    张贺飞; 刘艳娟; 曾正中

    2011-01-01

    [ Objective] The research aimed to reduce the sauce wastewater pollution to the environment and the cost of depth treatment of sauce wastewater. [ Method ] The sauce wastewater was treated by biological aerated filter to study its performance characteristics and influencing factors. [ Result ] The air-water ratio had greater impact on removal rate of COD than those on the color and the turbidity. Different hydraulic loading had a certain impact on the removal of COD and color. With the increase of hydraulic load, the removal rate of color had a downward trend, especially when the hydraulic load was 0.51 m3/( m2 · h). The removal rate of color and COD would be higher with the height of filter layer was higher. The removal rate of color and COD could reach 64.4% and 58.4% in the packing layer height for the 100 cm respectively. [ Conclusion] The chroma turbidity and COD in sauce wastewater could be well removed by BAF with spongy iron and argil granules. When the hydraulic load was 0.51 m3/(m2 · h) and the gas to liquid ratio was 2:1, the effects on various pollutants were the best.%[目的]减少酱油废水给环境带来的污染,降低酱油废水深度处理的费用.[方法]采用曝气生物滤池对酱油废水2级好氧处理出水进行深度处理,研究其性能特点和影响因素.[结果]不同气水比对废水COD去除效果的影响要大于对色度、浊度去除的影响;不同水力负荷对COD、色度的去除均有一定影响,色度的去除随水力负荷的增加去除率有所下降,当水力负荷为0.51 m3/(m2·h)时对污染物的去除效果最为理想;废水色度和COD去除率与填料层高度的关系为随高度增加而升高,在100 cm处对废水色度和COD去除率达到64.4%和58.4%.[结论]曝气生物滤池以陶粒-海绵铁混合填料可以很好地去除酱油废水2级好氧出水中的色度和浊度,进一步降低废水COD,在气水比为2∶ 1、水力负荷为0.51 m3/(m2·h)时对各种污染物的效果最好.

  16. Study on the influencing factors of nitrogen removal using the biological aerated filter under the condition with mercury ions%含Hg2+条件下曝气生物滤池脱氮影响因素的研究

    Institute of Scientific and Technical Information of China (English)

    吴文清; 黄少斌; 张瑞峰; 肖先念

    2012-01-01

    The selected Pseudomonas putida should be inoculated in the biological aerated filter,simulating the system for the denitrifying treatment of the wastewater containing mercury ions. The influences of carbon source, C/N,NH4+-N concentration,HRT,gas-water ratio and complexing agent (EDTA,Na-citrate) on denitrification effectiveness in the biological aerated filter are investigated emphatically. It is found that the mercury ion could stimulate the aerobic nitrobacteria to promote denitrification,and that the removal of Hg2+ and denitrification are conducted simultaneously.%将已筛选出的恶臭假单胞菌接种于曝气生物滤池中,模拟该系统对含Hg2+废水进行脱氮处理,重点考察碳源、碳氮比、NH4+-N初始质量浓度、水力停留时间(HRT)、气水比、络合剂(EDTA和柠檬酸钠)等对脱氮效果及Hg2+浓度变化的影响.研究发现Hg2+对好氧反硝化菌有刺激作用,促进了反硝化进程,而且Hg2+的脱除与反硝化是同步进行的.

  17. 曝气生物滤池处理高氨氮含铍废水研究%Treatment of Beryllium Containing Wastewater with High Ammonia Concentration by Biological Aerated Filters

    Institute of Scientific and Technical Information of China (English)

    孙芳; 孙卫玲

    2012-01-01

    含铍废水具有较高的毒性,目前关于其处理方法的研究较少.文章针对铍冶炼废水中铍超标以及高氨氮浓度的问题,选取接种有微生物的曝气生物滤池(BAF)工艺同时去除氨氮和铍,并分析其去除铍的机理.反应器系统的长期运行结果表明,BAF对高氨氮含铍废水具有较好的处理效果.在进水氨氮浓度200 mg/L,铍浓度50~100μg/L,停留时间24h条件下,处理出水氨氮浓度稳定在1.8~10.0 mg/L,铍浓度小于5μg/L.BAF主要通过系统中的微生物去除铍,载体对铍的吸附量较小,用Langmuir模型对吸附数据进行拟合,得到微生物对铍的吸附容量为684.9 μg/g.形态提取实验表明,被微生物去除的铍主要以有机结合态存在,且微生物细胞表面对铍的吸附量有限,大量的铍富集于微生物细胞内,为此,BAF对铍有长期稳定的处理效果.%Beryllium-containing waste water is of high toxicity, but there are limited researches concerning its treatment. Beryllium smelting wastewater contains high concentrations of beryllium and ammonia. Biological aerated filters (BAF), which was inoculated with microorganisms, was used to treat beryllium smelting wastewater, and the mechanisms involved were investigated. Results show that BAF could remove beryllium and ammonia simultaneously. When influent concentrations of ammonia nitrogen and beryllium were 200 mg/L and 50-100 μg/L respectively, HRT was 24 h, the concentration ammonia was in the range of 1.8~10.0 mg/L, and beryllium concentration was less than 5 μg/L in the effluent. The removal of beryllium was mainly attributed to the microorganisms in BAF, and the maximum uptake of beryllium by microorganisms calculated by Langmuir equation was 684.9 μg/g. The beryllium removed by BAF was mainly combined to organic fraction. Moreover, large amount of beryllium accumulated inside the cell with limited biosorption by the external surface of microorganisms. Therefore, high removal

  18. Biological iron oxidation by Gallionella spp. in drinking water production under fully aerated conditions.

    Science.gov (United States)

    de Vet, W W J M; Dinkla, I J T; Rietveld, L C; van Loosdrecht, M C M

    2011-11-01

    Iron oxidation under neutral conditions (pH 6.5-8) may be a homo- or heterogeneous chemically- or a biologically-mediated process. The chemical oxidation is supposed to outpace the biological process under slightly alkaline conditions (pH 7-8). The iron oxidation kinetics and growth of Gallionella spp. - obligatory chemolithotrophic iron oxidizers - were assessed in natural, organic carbon-containing water, in continuous lab-scale reactors and full-scale groundwater trickling filters in the Netherlands. From Gallionella cell numbers determined by qPCR, balances were made for all systems. The homogeneous chemical iron oxidation occurred in accordance with the literature, but was retarded by a low water temperature (13 °C). The contribution of the heterogeneous chemical oxidation was, despite the presence of freshly formed iron oxyhydroxides, much lower than in previous studies in ultrapure water. This could be caused by the adsorption of natural organic matter (NOM) on the iron oxide surfaces. In the oxygen-saturated natural water with a pH ranging from 6.5 to 7.7, Gallionella spp. grew uninhibited and biological iron oxidation was an important, and probably the dominant, process. Gallionella growth was not even inhibited in a full-scale filter after plate aeration. From this we conclude that Gallionella spp. can grow under neutral pH and fully aerated conditions when the chemical iron oxidation is retarded by low water temperature and inhibition of the autocatalytic iron oxidation.

  19. Combined process of biological aerated filter for the advanced treatment of recycled water reuse in thermal power plants%曝气生物滤池组合工艺深度处理中水回用于火电厂

    Institute of Scientific and Technical Information of China (English)

    张文耀

    2014-01-01

    介绍了内蒙古市政污水处理厂二级生物处理后的中水的深度处理工艺(机械搅拌澄清池和曝气生物滤池的组合工艺)流程和进出水水质情况,分析了机械搅拌澄清池和曝气生物滤池的工艺特点。经深度处理后,出水COD、氨氮、总磷等水质指标均显著降低,完全符合回用要求,能够满足火电厂生产需要。实践表明,该处理工艺可缓解水资源紧张的现状,有着广泛的应用前景。%The advanced treatment process flow (combined mechanical stirring clarification pool+biological aerated filter process) of the recycled water after being treated by secondary biological treatment in Inner Mongolia Munici-pal Sewage Treatment Plant and the situation of its influent and effluent water quality are introduced. The technolog-ical characteristics of the stirring clarification pool and biological aerated filter are analyzed. After the advanced treatment,the water quality indexes,such as the effluent COD,ammonia nitrogen,total phosphorus,etc.,are all de-creased obviously,meeting completely the reuse requirements and satisfying the production needs of thermal power plants. Practice results show that the treatment process can ease the water resource shortage situation ,having wide application prospect.

  20. 水渣滤料-曝气生物滤池去除生活污水中污染物的效能研究%Research on Removal Efficiency of Contamination in Domestic Sewage by Water Quenched Slag Filter Medium Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    于衍真; 韩雯雯; 毕于顺; 冯岩

    2011-01-01

    为解决水渣对环境的污染及综合利用的问题,以水渣为主要原料,添加黏结剂和成孔剂,经混合、成球、养护制成免烧型水渣滤料.在直径为150mm,滤料层高为1500mm的水渣滤料曝气生物滤池(WBAF)中处理生活污水.结果表明,在温度为20~27℃,pH为7.0~8.0,气水比为5:1,进水ρCONDcr=167.58mg/L、浊度=34.60NTU、ρ(NH4^+-N)=36.45mg/L时,相应的出水指标为PCODcr=37.73mg/L、浊度=7.57NTU、ρ(NH4^+-N):5.39mg/L,符合国家污水综合排放标准(GB8978-1996)一级标准.氨氮去除效果明显是因为水渣滤料能溶出碱性物质,为硝化反应提供了碱度.%In order to dipose of the enviromental pollution caused by blast furnace water quenched slag and its comprehensive utilization, water quenched slag was adopted as dominating material mixed with bond and poreforming agent by commingle, conglobate and conseve to make avoiding-burning water quenchde slag filter medium. A pilot scale Water quenched slag filter medium Biological Aerated Filter (WBAF) of 150 mm in diameter and 1 500 mm in media height was tested to treat domestic Sewage. The results showed that PCODcr, = 37.73 mg/L,turbidity = 7.57 NTU,ρ(NH4^+-N) 5.39 mg/L when the corresponding influent concentration was 167.58 mg/L,34.60 NTU ,36.45 mg/L, respectively, under the conditions of T = 20 - 27 ℃ , pH = 7.0 - 8.0 and gas/ liquid = 5: 1. The quality indexes of the domestic sewage after treatment conform with the national discharge standards. The water quenched slag filter medium has higher ammonia nitrogen removal efficiency that because it can sufficiently supply alkalinity by dissolving alkaline substances.

  1. 填料对新型曝气生物滤池污水处理效能试验研究%Experimental Study on the Filling to the Performance of New-Type Biological Aerated Filter for Domestic Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    司马卫平; 龙剑波

    2011-01-01

    采用新型酶促厌氧填料、半软性填料、酶促好氧填料和PYC挂膜陶粒填料对两段错向流曝气生物滤池反应器进行污水处理试验研究,分析了4种填料对反应器污水处理效能的贡献并为反应器填料的选择提供科学依据.结果表明,以半软性填料和酶促好氧填料为组合填料的两段错向流曝气生物滤池反应器污水处理效能均优于其它填料.%A two-sect up and down flow biological aerated filter (TUDBAF), with enzyme-enhanced anaerobic bio-filling, semi-soft filling, enzyme-enhanced aerobic bio-filling and PYC filling, was used to treat domestic wastewater. It studied the effectiveness of the four types filling on the wastewater treatment reactor to provide scientific basis for the choice of filling. The results show that performance of TUDBAF with semi-soft filling and enzyme-enhanced aerobic bio-filling are superior to other fillings.

  2. 曝气生物滤池工艺脱氮性能及反硝化细菌群落结构特征研究%Study on the Nitrogen Removal Performance and the Characteristics of Denitrification Bacterial Community Structure of Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    彭晓兰; 刘聪; 陈吕军

    2012-01-01

    The nitrogen removal performance and the denitrification bacterial community structure of two pre-denitrification biological aeration filter(BAF) processes with different media combinations,the ceramic-zeolite BAF process(C-Z BAF) and the zeolite-ceramic BAF process(Z-C BAF),were compared at different C/N ratios.The results showed that the average TN removal efficiency of Z-C BAF was higher than that of C-Z BAF,and the advantage was more notable at low C/N ratio.When the C/N ratio decreased to 3.3,the average TN removal efficiency of Z-C BAF was 20% higher than that of C-Z BAF.Comparing the microbial community structure of the two combinations at different C/N ratios,it was found that the richness and diversity of denitrification bacterial community decreased significantly with the decrease of C/N ratio.At low C/N ratio,within the whole oxic filter of Z-C BAF,nosZ genetic T-RFs were detected with more than 20% relative abundance,whereas no nosZ genetic T-RFs were detected at the upper oxic filter of C-Z BAF by PCR amplification.The results indicated that the simultaneous nitrification and denitrification function of Z-C BAF was better than that of C-Z BAF.At low C/N ratio,the nitrogen removal efficiency of Z-C BAF was obviously higher than that of C-Z BAF.Thus,compared to C-Z BAF,Z-C BAF had greater potential on the treatment of wastewater with low organic concentration and low C/N ratio.%比较了两组不同填料组合的前置反硝化曝气生物滤池(biological aeration filter,BAF)脱氮工艺:陶粒-沸石BAF工艺(C-Z BAF)和沸石-陶粒BAF工艺(Z-C BAF),在不同C/N条件下的脱氮效果及滤料表面的反硝化细菌群落结构特征.结果表明,Z-C BAF对TN的平均去除效率高于C-Z BAF,且在低C/N条件下Z-C BAF的优势更加明显,当C/N为3.3时Z-C BAF的TN平均去除率比C-Z BAF高出20%.测定2种组合在不同C/N条件下的反硝化细菌群落结构发现,随着C/N的降低,2种组合反硝化细菌

  3. Removing Iron and Manganese Simultaneously from Ground Water Using One-stage Biological Filter

    Institute of Scientific and Technical Information of China (English)

    XUE Gang; GAO Pin; GONG Qing-jie

    2009-01-01

    A novel process for removing iron and manganese simultaneously in ground water, which consisted of simple aeration and one-stage filtration, was developed in this research. It was found that the biological process had much higher manganese removal efficiency than chemical contact oxidation process. At the same time, the optimal operation parameters of aeration and biological filtration such as DO concentration and pH after aeration, filtration rate before and after startup, filtration operation cycle and backwashing rate, etc., were also obtained by experiments. By analyzing water quafity in different positions of filter bed, it was found that the oxidation of Fe2+ in biological filter bed adapted to first-order reaction, whereas the oxidation of Mn2+ conformed to zero-order reaction, which could be explained by Michaelis-Menten enzyme reaction equation when substrate concentration was far more than bacteria amount.

  4. Pilot-scale study on treatment of the secondary biochemical effluent from sewage factory with biological aerated filter%曝气生物滤池补充处理污水厂出水的中试研究

    Institute of Scientific and Technical Information of China (English)

    宁艳春; 李忠臣; 高兴波; 蒲文晶; 韩文举; 邱延波; 吕利民; 庄立波; 袁伟

    2012-01-01

    针对某污水处理厂二级生化出水,开展了曝气生物滤池中试实验研究.分别开展了下向流和上向流滤池形式的实验研究,通过对比实验,最终确定适宜的滤池形式和滤料;并对气水体积比、水力负荷、水温等影响因素进行了分析和讨论,优化操作条件,确定了工艺的最佳操作参数.通过活性炭、陶粒2种滤料的微观结构对比,对反应机理进行了探讨.中试实验结果表明:上向流曝气生物滤池(活性炭、陶粒混装滤料)对污水厂二级生化出水进行补充处理,可以使污水厂出水COD指标达到污水综合排放标准(GB8978-1996)的一级标准.%The pilot experiment of BAF was used to treat the secondary biochemical effluent from sewage factory. The contrasting experiment was carried out on two modes of BAF (UBAF and DBAF), and two kinds of carriers (ceramic granule and activated carbon). By comparing, the optimum BAF form and filter materials were determined finally. The principal influencing factors of BAF were the ratio of air to water, hydraulic loading, water temperature. And the operational conditions were optimized, and defined the best operation parameter to obtain the optimization resolution. The result showed: that using two-stage UBAF which is filled with ceramic granule and activated carbon,treated the secondary biochemical effluent, the effluent quality can achieve the first level criteria specified in the Integrated Wastewater Discharge Standard (GB 8978-1996).

  5. A Trade Study of Two Membrane-Aerated Biological Water Processors

    Science.gov (United States)

    Allada, Ram; Lange, Kevin; Vega. Leticia; Roberts, Michael S.; Jackson, Andrew; Anderson, Molly; Pickering, Karen

    2011-01-01

    Biologically based systems are under evaluation as primary water processors for next generation life support systems due to their low power requirements and their inherent regenerative nature. This paper will summarize the results of two recent studies involving membrane aerated biological water processors and present results of a trade study comparing the two systems with regards to waste stream composition, nutrient loading and system design. Results of optimal configurations will be presented.

  6. Submerged aerated bio-filter (SAB)--a post treatment option for UASB effluent treating sewage.

    Science.gov (United States)

    Sudhir, Padigala; Gaur, Rubia Zahid; Khan, Abid Ali; Kazmi, A A; Mehrotra, Indu

    2013-07-01

    This paper presents exploratory results of the performance of submerged aerated bio-filter (SAB-1.5 L) for the post treatment of UASB effluent treating sewage in order to bring the effluent quality in compliance with discharge standards. The study was carried out in three stages with varied dissolved oxygen (DO) levels of 0 to 2.0, 2.0 to 4.0, 4.0 to 6.0 and > 6.0 mg/L. The hydraulic retention time (HRT) and hydraulic loading rate (HLR) were maintained 0.67 h & 0.1 m3/ m2 x h respectively in all stage of study. The performance in terms of BOD removal efficiency was increased with increase in DO levels. Results revealed that the average BOD and SS removal efficiencies in phases 3 and 4 were 51.3 and 59.5% and 58.8 and 67.5% respectively. Significant ammonical nitrogen (NH4-N) removal of 60% was observed in phase 4. The BOD and SS in phases 3 and 4 were reduced to well below the effluent disposal standards. The SAB at DO ≥ 4 mg/L can be considered a viable alternative for the post treatment of effluent from UASB treating domestic wastewater.

  7. Study on efficiency of refractory linear alkyl-benzene sulfonates(LAS) removal from synthetic detergent wastewater by novel up-flow biological aerated filter%新型UBAF处理合成洗涤剂废水中降解LAS的效能研究

    Institute of Scientific and Technical Information of China (English)

    纪桂霞; 周步轩; 张欢; 刘弦

    2012-01-01

    通过在清水区悬挂生物绳软填料的上向流曝气生物滤池处理合成洗涤剂废水的试验,研究了水力负荷、气水比、污染负荷、滤层高度及溶解氧等对LAS处理效能的影响.结果表明:水力负荷、气水比及滤层厚度是新型UBAF处理效能的主要影响因素,进水污染负荷对LAS处理效能的影响不显著.废水LAS浓度与流经的滤层厚度存在很好的指数关系:Ch=C0ekh.新型UBAF的挂膜性能好,启动速度快,对COD、LAS的处理效能有一定提高.在水力负荷1.1 m3/(m2·h),气水比3∶1~4∶1的运行条件下,对典型合成洗涤剂废水中的LAS去除率达80%以上,处理水的LAS指标达到排放标准.%To improve the efficiency of up - flow biological aerated filter, fixed bio - cord in clarifying region was proposed and the novel system named NUBAF was applied on laboratory scale. Through study the effects of hydraulic loading, ratio of air to liquid, pollution load, media height and DO on linear alkyl - benzene sulfonates ( LAS) treatment performance using this new process and the results indicated that the hydraulic loading, ratio of air to liquid and media height were the main factors to the NUBAF performance , but the effect of the pollution load on the NUBAF performance was unremarkable. The removal efficiency of LAS could be up to 80 % under the optimal conditions; the hydraulic loading of 1. 1 mV (m2 ? H) , ratio of air to liquid of 3= 1 ~4: 1 (based on 3.3 mV (m2 ? H) :1. 1 m3/ (m2 ? H) ) , besides, there was an exponential relationship between the concentration of LAS and media height expressed as Ch = C0ekh. After treated by NUBAF, effluent was greatly improved to reach the discharge standards of China.

  8. 高速给水曝气生物滤池应用于大型自来水厂的预处理%Application of High-Rate Up-Flow Biological Aerated Filter to Pretreatment for Large-Scale Waterworks

    Institute of Scientific and Technical Information of China (English)

    陆少鸣; 李芳; 李少文

    2012-01-01

    In order to avoid the micro-pollution of drinking water source due to ammonia nitrogen (NH3-N) and or-ganics, for the first time, a waterworks in Guangzhou city adopted the high-rate up-flow biological aerated filter ( HUBAF) with a flow rate of 735 thousand ton per day as a pretreatment process. In the first three months after the stable operation, the NH3-N content and CODMn in raw water respectively reached 0. 44 ~ 2. 22 mg/L and 1. 84 ~ 6. 06 mg/L, and those in the pretreatment effluent were respectively below 0.5mg/L and 2. Omg/L. Moreover, the iron and manganese contents in the raw water were respectively up to 1. 16 and 0.22 mg/L, while those in the waterworks effluent were respectively 0. 05 and 0. 03 mg/L. Due to the large-particle ceramic filter media combined with fluid-bed technology, the average removal of turbidity was only about 2.5 NTU and the head loss was steadily below 1.0m. HUBAF adopts an air-water-combined backwashing system with up-and-down flow, which keeps the change of head loss within 0.1m and makes it possible to share a common aeration system in the filter. The application of HUBAF demonstrates that, as compared with the biological pretreatment technologies that have been put into application, such as the elastic packing-contact oxidation technology and the suspended-ball fluidized technology, HUBAF possesses stronger resistance to impact loading, higher NH3-N nitration rate and better removal of iron and manganese, and that the "HUBAF-conventional treatment" combined system is of a organics removal similar to that of the "O3-BAC" advanced process.%为克服氨氮和有机物对饮用水源的微污染,广州市某水厂首次采用了高速给水曝气生物滤池(HUBAF)生物预处理新工艺,处理规模为73.5万m3/d.工程投产稳定运行后,初期3个月原水氨氮和CODMn分别为0.44~2.22 mg/L和1.84~6.06 mg/L,预处理出水分别小于0.5 mg/L和2.0mg/L;原水的铁和锰最高达1.16 mg/L和0.22 mg

  9. 不同流向对曝气生物滤池处理对对虾养殖污水效果的影响%Effect of different flows on wastewater treatment during Litopenaeus Vannamei culture by biological aerated filters

    Institute of Scientific and Technical Information of China (English)

    陈强; 黎中宝; 张艳艳; 王晨晨; 王超; 于凌宇

    2012-01-01

    In this experiment, the up-flow biological aerated filter ( UBAF) and down - flow biological aerated filter ( DBAF) were adopted to treat aquacultural wastewater of Litopenaeia vannamei. Trie water quality indexes such as chemical oxygen demand (COD), ammonia nitrogen ( NH3-N), nitrate nitrogen (N03 ~-N), nitrite nitrogen (NO2 -N), inorganic nitrogen (DIN) and soluble reactive phosphates (PO4-P) were measured and analysed during 30 days processing. The study was focused on the effect of the purification characteristics for aquacultural wastewater. Both the operating condition and the polluted condition of the wastewater treatment were also observed. The results showed that the removal rates and stability of UBAF was superior than that of DBAF. When the efluent concentrations of COD, NH3-N, NO," -N, N02--N, DINandPO1-Pwere7.62~8.20mg/L, 0.62 ~0.65 mg/L, 0.54-0. 59 mg/L, 0.23-0.27 mg/L, 1.40 -1.47 mg/L, 0.24 -0.29 mg/L, respectively, the removal rates of COD, NH,-N, N03~-N, NO2"-N, DIN and P04-P were 45.2% , 88.9% , 58.5% , 78.8% , 75.3% and 25. 1% , respectively at the temperature of 25 t - 30 *C by UBAF. The removal rates of NH3-N were the highest, fouowed by NO2" -N and DLN, COD and NO3" -N was lower, and PO4-P the lowest%采用上流式和下流式曝气生物滤池处理凡纳滨对虾(Litopenaeus vannamei)养殖污水,连续进行30 d,分析出水水质,并观察系统运行情况和装置污染状况.研究了养殖污水中化学需氧量、氨氮、硝酸盐氮、亚硝酸盐氮、无机氮及活性磷酸盐6项指标的去除效果.实验结果表明:从养殖污水主要污染物指标的去除效果和稳定性上看,上流式优于下流式曝气生物滤池.在系统进水化学需氧量质量浓度为7.62 ~8.20 mg/L、氨氮质量浓度为0.62~0.65 mg/L、硝酸盐氮质量浓度为0.54~0.59 mg/L、亚硝酸盐氮质量浓度为0.23 ~0.27 mg/L、无机氮质量浓度为1.40~1.47 mg/L、活性磷酸盐质量浓度为0.24 ~0.29 mg

  10. Effect of aeration modes on the characteristics of composting emissions and the NH3 removal efficiency by using biotrickling filter.

    Science.gov (United States)

    Wu, Chuanfu; Wang, Qunhui; Sun, Xiaohong; Xue, Niantao; Liu, Shu; Xie, Weimin

    2011-08-01

    A pilot biotrickling filter (BTF) packed with ZX02 fibrous balls as packing material was tested for the treatment of ammonia (NH(3)) released from a composting plant of dairy manure. In order to investigate the effects of three compost aeration modes (mode Co-I, Co-II and In-II) on the NH(3) removal efficiency, a field experiment was continuously carried out for more than eight months. The results demonstrated that under the intermittent aeration mode (In-II), the NH(3) removal efficiency reached 99.2±0.1% when the inlet NH(3) concentration was 7.5-32.3mg m(-3) (9.8-42.5ppmv). The maximum and critical elimination capacity of the biotrickling filter was 22.6 and 4.9g NH(3)m(-3)h(-1), respectively. The effluent concentration of NH(3) was lower than 1.0mg m(-3), which meets the first class discharge standards of GB14554-93. When the concentration of free ammonia in the trickling liquid was varied from 0.1 to 0.4mg L(-1), the nitrification yield was between 47.9% and 103.8%. In addition, the optimum liquid tricking velocity (LTV) of the biotrickling filter was 0.5m(3)m(-2)h(-1) for low inlet concentrations and 2.2m(3)m(-2)h(-1) for high inlet concentrations. Therefore, the use of the biotrickling filter for the compost under the third aeration mode (In-II) yielded an effective optimum NH(3) removal and reduced the nitrogen loss in the compost.

  11. Modeling the Performance of Biological Rapid Sand Filters Used to Remove Ammonium, Iron, and Manganese From Drinking Water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.;

    filter management to performance . Biological rapid sand filters are used for the dual purpose of particle removal (including microorganisms) and contaminant removal through biological activity on the filter media. For drinking water treatment in the United States, biological filters use granular......Although biological rapid sand filters are a well established technology for treating drinking water, there is still a lack of scientific understanding of the processes controlling their performance. For example, the distribution and role of microorganisms in contaminant removal in the filter has...... for chlorine addition following treatment. Under the normal conditions found in many water treatment plants, reduced iron can be oxidized through aeration and the precipitates can be captured by the filter media. Ammonium and manganese can be removed biologically. This research uses both pilot and full scale...

  12. [Biocenotic dynamics of liquid sewage in the process of its biological purification at aeration stations].

    Science.gov (United States)

    Kalina, G P; Vinogradova, L A; Gipp, E K

    1975-08-01

    A study was made of biological purification of sewage at the aeration stations on the quantitative composition of the main indicator microbes--of bacteria of the coliform group and of the fecal coliform bacilli, enterococci, Proteus, and also pathogenic enterobacteria. There was found a difference in the behaviour of different species of Proteus, i.e. reduction in the process of purification in the numbers of Pr. mirabilis, and a sharp elevation of Pr. morganii content. There was noted an insignificant amount of Pr. vulgaris both before and after the biological purification. It was found that dynamics of biocenosis was influenced by air temperature at the time of collection of the samples. A possibility of reproduction of coliform bacilli serving as one of the factors of autopurification of sewage during the biological purification was confirmed.

  13. 不同填料组合的曝气生物滤池前置反硝化工艺特性的比较研究%Comparitive study on two biological aerated filter processes with different media combination for pre-denitrification/nitrification of grey water

    Institute of Scientific and Technical Information of China (English)

    彭晓兰; 陈吕军

    2012-01-01

    The performance and characteristics of two separated pre-denitrification processes using biological aerated filter(BAF),ceramic-zeolite BAF(C-Z BAF),and zeolite-ceramic BAF(Z-C BAF),were investigated and compared under various HRTs,reflux ratios and air-liquid ratios for treating grey water.The optimized HRT,air-liquid ratio and reflux ratio of C-Z BAF and Z-C BAF were 1.5 h,5∶ 1,1∶ 1 and 1.5 h,5∶ 1,2∶ 1,respectively,while influent volumetric loading rates for COD,NH3-N and TN were 0.72~5.97,0.09~0.60,and 0.11~0.78 kg/m3·d.Under the optimal conditions,the mean removal efficiency of COD,NH3-N,and TN were 94.7%,99.0% and 62.2%,respectively for the C-Z BAF;and 93.2%,99.5%,and 70.1%,separately for the Z-C BAF.The results of one-way ANOVA showed that HRT had significant effect on the removal of COD,NH3-N and TN of both processes;reflux ratio had significant effect on the TN removal of Z-C BAF while had no significant effect on that of C-Z BAF.The profile of pollutants along the flow path in the two BAF systems indicated that the COD was oxidized in the anoxic filter and the media of 0~0.3 m in oxic filter;the nitrification mainly happened in the media of 0~0.6 m in oxic filter and the Z-C BAF had higher nitrification rate than C-Z BAF;Z-C BAF had remarkable simultaneous nitrification and de-nitrification phenomenon,thus the de-nitrification efficiency of Z-C BAF was better than that of C-Z BAF.%研究了2组不同填料组合的前置反硝化曝气生物滤池(BAF)脱氮工艺:陶粒-沸石工艺(C-Z BAF)和沸石-陶粒工艺(Z-C BAF),比较二者在不同的水力停留时间(HRT)、气水比和回流比条件下的工艺特性。当进水COD、氨氮和TN容积负荷分别为0.72~5.97、0.09~0.60和0.11~0.78 kg/(m3.d)时,C-Z BAF和Z-C BAF的最佳HRT、气水比和回流比分别为1.5 h、5∶1、1∶1和1.5 h、5∶1、2∶1,相应COD、氨氮和TN的平均去除率分别为94.7%、99.0%、62.2%和93.2%、99.5%、70

  14. A biological oil adsorption filter.

    Science.gov (United States)

    Pasila, Antti

    2004-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore.

  15. A biological oil adsorption filter

    Energy Technology Data Exchange (ETDEWEB)

    Pasila, A. [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

    2005-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  16. STUDY ON APPLICATION OF AERATION BIOLOGICAL FLUID TANK TECHNOLGY IN NH4+—N WASTE WATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    CHENYi; LUJian-guo

    2003-01-01

    This paper introduces an application of "Aeration biological fluid tank"technology (ABFT) for the treatment of waste water containing NH4+-N and high concentrated chemicals.Highlights were focused on the effects of dissolved oxygen,pH,temperature and retention time on waste water bilogical treatment in order to find out a new approach in treatment of waste time on containing high concentrated NH4+-N.

  17. Photosynthetic aeration in biological wastewater treatment using immobilized microalgae-bacteria symbiosis.

    Science.gov (United States)

    Praveen, Prashant; Loh, Kai-Chee

    2015-12-01

    Chlorella vulgaris encapsulated in alginate beads were added into a bioreactor treating synthetic wastewater using Pseudomonas putida. A symbiotic CO2/O2 gas exchange was established between the two microorganisms for photosynthetic aeration of wastewater. During batch operation, glucose removal efficiency in the bioreactor improved from 50% in 12 h without aeration to 100% in 6 h, when the bioreactor was aerated photosynthetically. During continuous operation, the bioreactor was operated at a low hydraulic retention time of 3.3 h at feed concentrations of 250 and 500 mg/L glucose. The removal efficiency at 500 mg/L increased from 73% without aeration to 100% in the presence of immobilized microalgae. The initial microalgae concentration was critical to achieve adequate aeration, and the removal rate increased with increasing microalgae concentration. The highest removal rate of 142 mg/L-h glucose was achieved at an initial microalgae concentration of 190 mg/L. Quantification of microalgae growth in the alginate beads indicated an exponential growth during symbiosis, indicating that the bioreactor performance was limited by oxygen production rates. Under symbiotic conditions, the chlorophyll content of the immobilized microalgae increased by more than 30%. These results indicate that immobilized microalgae in symbiosis with heterotrophic bacteria are promising in wastewater aeration.

  18. Degradation efficiency and mechanism of azo dye RR2 by a novel ozone aerated internal micro-electrolysis filter.

    Science.gov (United States)

    Zhang, Xian-Bing; Dong, Wen-Yi; Sun, Fei-Yun; Yang, Wei; Dong, Jiao

    2014-07-15

    A newly designed ozone aerated internal micro-electrolysis filter (OIEF) was developed to investigate its degradation efficiencies and correlated reaction mechanisms of RR2 dye. Complete decolorization and 82% TOC removal efficiency were stably achieved in OIEF process. Based on the comprehensive experimental results, an empirical equation was proposed to illustrate the effects of initial dye concentration and ozone dosage rate on color removal. The results indicated that OIEF process could be operated at wide pH range without significant treatment efficiencies change, while the optimum pH for RR2 dye degradation was 9.0. There were 15, 8 and 6 kinds of identified intermediates during ozonation, IE and OIEF treatment processes, respectively. Less identified intermediates and their lower concentrations in OIEF may attribute to its rather excellent mineralization performance. It was found that ozonation, Fe(2+)/Fe(3+) catalyzed ozonation, the redox reactions of electro-reduction and electro-oxidation are the most important mechanisms in OIEF process. The catalytic effect of Fe(2+)/Fe(3+) would induce mutual conversion between dissolved Fe(2+) and Fe(3+), and then decrease the dissolution rate of ZVI. The excellent treatment performance proved that the OIEF process is one promising technology applied for reactive azo dyes and other refractory wastewater treatment.

  19. 去除致嗅物质的不同填料曝气生物滤池的启动特性与去除效果比较%Comparison of Start-up Characteristics and Odorant Removal Efficiencies of Biological Aerated Filters Different in Filling

    Institute of Scientific and Technical Information of China (English)

    吴媛媛; 杨宁宁; 邓超; 文湘华; 闫海; 孙体昌

    2013-01-01

    搭建了填料分别为生物陶粒(CPs)和颗粒活性炭(GAC)的2个曝气生物滤池(BAF)反应器,通过考察土嗅素和2-甲基异崁醇(2-MIB)这2种致嗅物质的去除效果和稳定周期,研究不同填料BAF的启动与挂膜特性.结果表明,在相同进水条件下,2种填料BAF去除溶解性总有机碳(DOC)的效率无明显差异,均在24d时达到稳定,且DOC去除率均基本稳定在70%以上.2种填料BAF去除土嗅素和2-MIB所需的启动时间有较大差异,CPs-BAF启动时间分别为30和26 d,而GAC-BAF启动时间分别为62和43 d.GAC-BAF和CPs-BAF对土嗅素的去除率分别稳定在约95%和69%,前者的去除率和稳定性明显高于后者;GAC-BAF和CPs-BAF对2-MIB的去除率分别稳定在约75%和73%,两者相差不大,但前者的稳定性强于后者.%Two biological aerated fiher (BAF) reactors using different fillings,separately,i.e.ceramic pellets (CPs)and granular active carbon (GAC),were built and used to remove geosmin and 2-MIB from water.Further,their startup characteristics were investigated by comparing odorant removal efficiencies and start-up time.At the same influent water,the two BAFs were quite similar in dissolved organic carbon (DOC) removal efficiency and both removal rates stabilized over 70% in 24 days.However,the two BAFs differed significantly in start-up time for removing geosmin and 2-MIB,separately,i.e.30 and 26 days respectively in CPs-BAF and 62 and 43 days respectively in GAC-BAF.Moreover,the geosmin removal rates in GAC-BAF and CPs-BAF were stable at about 95% and 69%,respectively,and the rate and stability for geosmin removal of the former was obviously higher than of the latter.And the removal rates of 2-MIB in GAC-BAF and CPs-BAF were similar to each other and stable at about 75% and 73%,respectively,but the stability of the former was higher than of the latter.

  20. Influence of phenol on ammonia removal in an intermittent aeration bioreactor treating biologically pretreated coal gasification wastewater.

    Science.gov (United States)

    Xu, Chunyan; Han, Hongjun; Jia, Shengyong; Zhao, Qian

    2016-05-01

    A laboratory-scale intermittent aeration bioreactor was investigated to treat biologically pretreated coal gasification wastewater that was mainly composed of NH3-N and phenol. The results showed that increasing phenol loading had an adverse effect on NH3-N removal; the concentration in effluent at phenol loading of 40mgphenol/(L·day) was 7.3mg/L, 36.3% of that at 200mg phenol/(L·day). The enzyme ammonia monooxygenase showed more sensitivity than hydroxylamine oxidoreductase to the inhibitory effect of phenol, with 32.2% and 10.5% activity inhibition, respectively at 200mg phenol/(L·day). Owing to intermittent aeration conditions, nitritation-type nitrification and simultaneous nitrification and denitrification (SND) were observed, giving a maximum SND efficiency of 30.5%. Additionally, ammonia oxidizing bacteria (AOB) and denitrifying bacteria were the main group identified by fluorescent in situ hybridization. However, their relative abundance represented opposite variations as phenol loading increased, ranging from 30.1% to 17.5% and 7.6% to 18.2% for AOB and denitrifying bacteria, respectively.

  1. Optimizing nitrification in biological rapid sand filters: Diagnosing and supplementing micronutrients needed for proper filter performance

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Wagner, Florian Benedikt; Boe-Hansen, Rasmus

    Nitrification is an important biological process commonly used in biological drinking water filters to remove ammonium from drinking water. Recent research has shown that a lack of micronutrients could be limiting the performance of these filters. Because nitrification is a biological process......, carbon, nitrogen, phosphorus and other micronutrients, such as copper, are required to ensure growth and activity. In nitrification, copper is a micronutrient that is needed in the amoA enzyme used by ammonia‐oxidizers to oxidize ammonium to nitrite. Increasing nitrification performance is needed in many...

  2. Noise Filtering and Prediction in Biological Signaling Networks

    CERN Document Server

    Hathcock, David; Weisenberger, Casey; Ilker, Efe; Hinczewski, Michael

    2016-01-01

    Information transmission in biological signaling circuits has often been described using the metaphor of a noise filter. Cellular systems need accurate, real-time data about their environmental conditions, but the biochemical reaction networks that propagate, amplify, and process signals work with noisy representations of that data. Biology must implement strategies that not only filter the noise, but also predict the current state of the environment based on information delayed due to the finite speed of chemical signaling. The idea of a biochemical noise filter is actually more than just a metaphor: we describe recent work that has made an explicit mathematical connection between signaling fidelity in cellular circuits and the classic theories of optimal noise filtering and prediction that began with Wiener, Kolmogorov, Shannon, and Bode. This theoretical framework provides a versatile tool, allowing us to derive analytical bounds on the maximum mutual information between the environmental signal and the re...

  3. 间歇曝气和连续曝气对生物脱氮除磷效果的比较%Biological Nitrogen and Phosphorus Removal Efficiency by Intermittent Aeration and Continues Aeration Compared

    Institute of Scientific and Technical Information of China (English)

    潘敏; 黄晓鸣

    2015-01-01

    Biological nitrogen and phosphorus removal was investigated by an intermittently aerated sequencing batch reactor IASBR and a sequencing batch reactor SBR . The removal efficiencies of ammonium⁃nitrogen NH4+⁃N were 99�30% and 98�73% respectively in IASBR and SBR in steady operation while phosphorus PO3-4 ⁃P removal efficiencies were 97�02% and 67�47% in IASBR and SBR respectively. The intermittent aeration pattern has better effect for biological phosphorus removal. Effluent NH4+⁃N PO3-4 ⁃P and COD concentrations in the IASBR meets ChinaⅠEmission Standards.%采用序批式生物反应器SBR系统,考察反应阶段的间歇曝气和连续曝气对模拟生活废水中氮和磷的去除效果。研究表明: IASBR和SBR对NH4+-N的去除率分别为99�30%和98�73%;对PO3-4-P的去除率分别为97�02%和67�47%。间歇曝气SBR对氨氮和磷酸根的去除率比连续曝气SBR高,有利于实现强化生物脱磷过程。间歇曝气SBR出水中氮、磷和COD浓度均达到了我国城镇污水处理厂污染物排放标准(GB 18918—2002)一级标准。

  4. Effect of a biological activated carbon filter on particle counts

    Institute of Scientific and Technical Information of China (English)

    Su-hua WU; Bing-zhi DONG; Tie-jun QIAO; Jin-song ZHANG

    2008-01-01

    Due to the importance of biological safety in drinking water quality and the disadvantages which exist in traditional methods of detecting typical microorganisms such as Cryptosporidium and Giardia,it is necessary to develop an alternative.Particle counts is a qualitative measurement of the amount of dissolved solids in water.The removal rate of particle counts was previously used as an indicator of the effectiveness of a biological activated carbon(BAC)filter in removing Cryptosporidium and Giardia.The particle counts in a BAC filter effluent over one operational period and the effects of BAC filter construction and operational parameters were investigated with a 10 m3/h pilot plant.The results indicated that the maximum particle count in backwash remnant water was as high as 1296 count/ml and it needed about 1.5 h to reduce from the maximum to less than 50 count/ml.During the standard filtration period,particle counts stay constant at less than 50 count/ml for 5 d except when influ-enced by sand filter backwash remnant water.The removal rates of particle counts in the BAC filter are related to characteristics of the carbon.For example,a columned carbon and a sand bed removed 33.3% and 8.5% of particles,respectively,while the particle counts in effluent from a cracked BAC filter was higher than that of the influent.There is no significant difference among particle removal rates with different filtration rates.High post-ozone dosage(>2 mg/L)plays an important role in particle count removal;when the dosage was 3 mg/L,the removal rates by carbon layers and sand beds decreased by 17.5% and increased by 9.5%,respectively,compared with a 2 mg/L dosage.

  5. The Application of Serf-made Microporous Aeration Device in the Coking Biological Dephenol System%自制微孔曝气装置在焦化生物脱酚系统上的应用

    Institute of Scientific and Technical Information of China (English)

    徐庆阳; 韩冰

    2011-01-01

    The self-made microporous aeration device was adopted as a substitution for the original stand pipe aeration device in the coking biological dephenol system in order to obtain a uniform aeration quantity and meet the requirements. After several years of operation, the aeration quantity achieved the technological requirements completely. The sludge settlement ratio increased as well. Comparing with the mature nylon nets microporous aeration device, the self-made pore aeration device saved cost and was easy to maintain.%针对焦化废水生物脱酚系统溶解氧过低的问题,通过淘汰原有竖管曝气装置,采用自制微孔曝气装置,使曝气量完全达到工艺要求,同时污泥沉降比得到提高,相比成熟的尼龙网微孔曝气装置,节约成本,便于维护.

  6. Impact of aeration and agitation on metabolic heat and protease secretion of Aspergillus tamarii in a real-time biological reaction calorimeter.

    Science.gov (United States)

    Dhandapani, Balaji; Mahadevan, Surianarayanan; Dhilipkumar, Sathish Sundar; Rajkumar, Suseela; Mandal, Asit Baran

    2012-06-01

    The effects of aeration and agitation on metabolic heat, alkaline protease production and morphology for Aspergillus tamarii MTCC5152 are reported in this manuscript. Measurement of metabolic heat has been attempted by the continuous and dynamic heat balance method in a biological real-time reaction calorimeter. At lower agitation intensities, growth-related processes were dominating. As a result the protease activity and the product heat yields were lower than those for 350 and 450 rpm. Although biomass growth was necessary to obtain maximum protease yield, agitation seemed to play a vital role in the protease production process. Energy dissipation per circulation function of the process is also deduced from power input. At optimal conditions, 350 rpm and 1 vvm, the gassed power required was 0.133 W. Pellet morphology and protease production were studied under different aeration and agitation intensities of A. tamarii. Pellet structure was considerably influenced by DO, a higher DO level resulted in denser pellets (1,018.4 kg/m(3)) leading to higher protease activity. Coupling of hydrodynamics and bio-reaction highlighted the complex relationship between energy dissipation, substrate uptake rate and fungal physiology. This study emphasised the potential of biocalorimetry as a reliable monitoring and robust control tool for aerobic fermentation of A. tamarii, using agricultural by-products.

  7. Biological Aerated Filter(BAF) in the Treatment of Waste–water from Blueberry Wine%曝气生物滤池(BAF)在处理蓝莓果酒废水中的应用

    Institute of Scientific and Technical Information of China (English)

    李凤林; 赵春娟; 刘磊

    2011-01-01

    Blueberry wine production waste–water of water quality,water quantity seasonal differences are large,higher concentrations of pollutants,in the case of concentrated organic wastewater,emissions will directly cause serious pollution to the environment.By using Biological Aerated Filter technology,CODcr,BOD5 and SS in waste–water removal rate up to 95%,97% and 89% respectively.System is stable,better handling.%蓝莓果酒生产废水的水质、水量季节性差异很大,污染物浓度较高,属中浓度有机废水,直接排放将对环境造成严重污染。采用曝气生物滤池工艺废水中CODcr、BOD5、SS去除率分别可达95%、97%、89%,系统运行稳定,处理效果较好。

  8. Biological sweetening of energy gases mimics in biotrickling filters.

    Science.gov (United States)

    Fortuny, Marc; Baeza, Juan A; Gamisans, Xavier; Casas, Carles; Lafuente, Javier; Deshusses, Marc A; Gabriel, David

    2008-03-01

    Removal of hydrogen sulfide from waste and energy-rich gases is required, not only because of environmental health and safety reasons, but also because of operational reasons if such gases have to be used for energy generation. A biotrickling filter for the removal of ultra-high concentrations of H2S from oxygen-poor gases is proposed and studied in this work. Two laboratory-scale biotrickling filters were used to study the startup period and to determine the long-term performance of the gas sweetening process. The inlet H2S concentration ranged from 900 to 12000ppmv and two different packing materials were investigated. There was no toxicity effect observed even at a the highest H2S concentration, and maximum elimination capacities of 280 and 250g H2Sm(-3)h(-1) were obtained at gas contact times of 167 and 180s, respectively. Elemental sulfur and sulfate were found to be the most abundant end-products of the biological oxidation of sulfide when operated under microaerophilic conditions. The biotrickling filter was able to quickly recover its nominal performance after different load increases and system shutdowns simulating field operation. The results reported here show that biotreatment can be an interesting alternative to conventional gas sweetening systems normally used for such applications.

  9. Biological drinking water treatment of anaerobic groundwater in trickling filters

    NARCIS (Netherlands)

    De Vet, W.W.J.M.

    2011-01-01

    Drinking water production from anaerobic groundwater is usually achieved by so called conventional techniques such as aeration and sand filtration. The notion conventional implies a long history and general acceptation of the application, but doesn’t necessarily mean a thorough understanding of the

  10. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter.

    Science.gov (United States)

    Gannoun, H; Bouallagui, H; Okbi, A; Sayadi, S; Hamdi, M

    2009-10-15

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/Ld. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  11. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

    Energy Technology Data Exchange (ETDEWEB)

    Gannoun, H.; Bouallagui, H.; Okbi, A. [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia); Sayadi, S. [Laboratory of bioprocesses, Centre of Biotechnology of Sfax, Sfax (Tunisia); Hamdi, M., E-mail: moktar.hamdi@insat.rnu.tn [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia)

    2009-10-15

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 deg. C) and thermophilic (55 deg. C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6 g COD/L d in mesophilic conditions and at OLRs from 0.9 to 9 g COD/L d in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/L d in mesophilic conditions, while the highest OLRs i.e. 9 g COD/L d led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/L d. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  12. STUDY ON APPLICATION OF AERATION BIOLOGICAL FLUID TANK TECHNOLGY IN NH+4-N WASTE WATER TREATMENT%曝气生物流化池(ABFT)技术在含氨氮污水治理的应用研究

    Institute of Scientific and Technical Information of China (English)

    陈怡; 卢建国

    2003-01-01

    This paper introduces an application of "Aeration biological fluid tank" technology (ABFT) for the treatment of waste water containing NH+4-N and high concentrated organic chemicals. Highlights were focused on the effects of dissolved oxygen, pH, temperature and retention time on waste water biological treatment in order to find out a new approach in treatment of waste water containing high concentrated NH+4-N.

  13. The Potential of Extended Aeration System for Sago Effluent Treatment

    Directory of Open Access Journals (Sweden)

    Wahi A. Rashid

    2010-01-01

    Full Text Available Problem statement: Sago effluent contains large amount of organic material which has a potential to cause water pollution. In order to reduce this problem, an experiment was conducted to remove organic material from sago effluent using lab scale of Extended Aeration (EA system. Approach: The EA system consisted of the combination of physical and biological treatment unit. For Physical Treatment Unit (PTU, the sago effluent was filtered using 710 µm mesh size filter. For Biological Treatment Unit (BTU, the effluent were mixed and aerated with activated sago sludge for 48 h. The treatment efficiency with respect to Biological Oxygen Demand (BOD, Chemical Oxygen Demand (COD and Total Suspended Solid (TSS removal were evaluated and compared with regulatory requirement by Department of Environment, Malaysia. Results: The result showed, the EA system could reduce BOD, COD and TSS up to 84, 87.8 and 73% respectively, however it did not comply with the regulatory requirement. Conclusion: This study suggested the EA system have potential to be apply on sago effluent, however it should be integrated with additional treatment unit to achieve the effluent quality standard.

  14. Electroporation of Biological Cells Embedded in a Polycarbonate Filter

    CERN Document Server

    Hercules, W A; Lindesay, J; Schmukler, R; Hercules, William A.; Lindesay, James; Coble, Anna; Schmukler, Robert

    2003-01-01

    The electropermeabilization of biological cell membranes by the application of an external field occurs whenever an applied field exceeds a threshold value. For fields above this threshold value but less than another critical value, the pores formed in the membrane are transient or reversible. Several mechanisms have been proposed for the formation of these transient pores. Here we examine the local electric fields generated for the configuration of cells embedded in a polycarbonate filter, both in the region in and around the pore. We consider the shear forces created in the membrane due to the gradient of the field along the surface of the membrane, and the interaction of the charged molecules in the membrane with this field. A relationship between the electric field strength and the size of the pore formed is derived.

  15. Diagnostics in biological rapid sand filters treating groundwater – governing factors for nitrification

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Gülay, Arda; Smets, Barth F.

    To improve the insight in the processes in biological rapid sand filters a range of methods were developed to diagnose the microbial mediated processes – particularly nitrification.......To improve the insight in the processes in biological rapid sand filters a range of methods were developed to diagnose the microbial mediated processes – particularly nitrification....

  16. Optimizing nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Smets, Barth F.; Lee, Carson Odell

    Addition of phosphate or trace metals or better management e.g. in terms of anmonium load can improve the nitrification rate and efficiency in biological rapid sand filters.......Addition of phosphate or trace metals or better management e.g. in terms of anmonium load can improve the nitrification rate and efficiency in biological rapid sand filters....

  17. Application of biological filters in water treatment systems

    Science.gov (United States)

    Hurley, T. L.; Bambenek, R. A.

    1973-01-01

    Silver chloride placed on or close to barrier kills bacteria as they arrive. Dead bacteria accumulate linearly, whereas previously, live bacteria accumulated exponentially. During continuous 30-day tests, no bacteriological contamination was found downstream of filters with silver chloride added.

  18. Effects of dynamic operating conditions on nitrification in biological rapid sand filters for drinking water treatment

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Boe-Hansen, Rasmus; Musovic, Sanin

    2014-01-01

    Biological rapid sand filters are often used to remove ammonium from groundwater for drinking water supply. They often operate under dynamic substrate and hydraulic loading conditions, which can lead to increased levels of ammonium and nitrite in the effluent. To determine the maximum nitrification...... and the full-scale filter. Nitrification rates and ammonia-oxidizing bacteria and archaea were quantified throughout the depth of the filter. The ammonium removal capacity of the filter was determined to be 3.4 g NH4–N m−3 h−1, which was 5 times greater than the average ammonium loading rate under reference...

  19. The biological treatment of petroleum tank draw waters

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Jose L. [Envirosystems Supply, Inc., Hollywood, FL (United States); Stephens, Greg [Plantation Pipeline, Atlanta, GA (United States)

    1993-12-31

    This work reviews and summarizes the performance of a biological process (followed by the state-of-the-art) for the removal of organic compounds in petroleum tank draw waters. Trickling filter and the extended aeration modification of activated sludge were selected as the biological processes tested in pilot units. 4 refs., 2 figs., 3 tabs.

  20. Winery Wastewater Treatment Applying Aerated Submerged

    Directory of Open Access Journals (Sweden)

    Alessandra Pellizzaro Bento

    2010-06-01

    Full Text Available The winery wastewater usually shows conditions of low pH, high organic loads and concentrations of carbon, nitrogen and phosphorus that are inappropriate for biologic treatment. The purpose of this research was to apply the technology of aerated submerged biofilter (ASB for the winery effluent treatment during the harvest (ASB 1 and non harvest (ASB 2 at lab scale. Therefore, two up flow biofilter built on glass (5 liters volume were installed. The nutrient balance of the winery wastewater was adjusted and the correction of the pH was done by oyster shell used as filter material. The efficiency removal (COD for the harvest reactor was 90% while for the non harvest was 82%. The oyster shells contributed to an increase on average of 180 mg/L of alkalinity to the BAS 1 and 318 mg/L for the BAS 2. As regards the metals, the average values in the treated effluent to meet iron and zinc is permitted by the environmental standards of Santa Catarina. Under the experimental conditions applied in this research, this kind of reactor has presented potential for the treatment of winery wastewater. However, operational improvements would be required in the reactors to adequate them to the specific management into the wineries.

  1. Endotoxin release from biologically active bench-scale drinking water anthracite/sand filters

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, W.B.; Mayfield, C.I.; Huck, P.M. [University of Waterloo, Waterloo, ON (Canada). Dept. of Civil and Environmental Engineering

    2008-12-15

    Endotoxin release from biologically active dual-media (anthracite/sand) bench-scale drinking water filters was investigated. The biological filters were typically net producers of endotoxin during normal operation with mean concentrations increasing from 6 endotoxin units (EU)/mL to 16 EU/mL in filter influent and effluent, respectively. The filter operating condition resulting in the greatest release of endotoxin occurred upon shutdown and subsequent restart, with the highest observed filter effluent endotoxin concentration being 745 EU/mL in the first pore volume following the return of flow through the filter. Effluent samples collected following filter shutdowns were chlorinated to determine the effect of bacterial cell death on endotoxin release. Chlorination did not induce immediate 'dumping' of endotoxin, nor did holding the chlorinated samples for 5 d result in an increase in aqueous endotoxin concentration. In addition to endotoxin, measurable quantities of potassium were detected in the interstitial water in the biofilter during shutdown periods. In order to reduce potential risk to dialysis patients and humidifier users, it is recommended that, following even short biofilter shutdowns, filters should be immediately backwashed or, failing this, the first five pore volumes of effluent water be discharged to waste to allow endotoxin levels to return to pre-shutdown values.

  2. Copper deficiency can limit nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Wagner, Florian Benedikt; Nielsen, Peter Borch; Boe-Hansen, Rasmus

    2016-01-01

    Incomplete nitrification in biological filters during drinking water treatment is problematic, as it compromises drinking water quality. Nitrification problems can be caused by a lack of nutrients for the nitrifying microorganisms. Since copper is an important element in one of the essential...... enzymes in nitrification, we investigated the effect of copper dosing on nitrification in different biological rapid sand filters treating groundwater. A lab-scale column assay with filter material from a water works demonstrated that addition of a trace metal mixture, including copper, increased ammonium...... removal compared to a control without addition. Subsequently, another water works was investigated in full-scale, where copper influent concentrations were below 0.05 μg Cu L-1 and nitrification was incomplete. Copper dosing of less than 5 μg Cu L-1 to a full-scale filter stimulated ammonium removal...

  3. An Efficient Machine Learning Approach To Low-Complexity Filtering In Biological Sequences

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Christopher A; Oehmen, Christopher S

    2012-06-09

    Biological sequences contain low-complexity regions (LCRs) which produce superfluous matches in homology searches, and lead to slow execution of database search algorithms such as BLAST. These regions are efficiently identified by low-complexity filtering algorithms such as SDUST and SEG, which are included in the BLAST tool-suite. These algorithms target differing notions of complexity, so an algorithm which combines their sensitivities is pursued. A variety of features are derived from these algorithms, as well as a new filtering algorithm based on Lempel-Ziv complexity. Artificial sequences with known LCRs are used to train and evaluate an SVM classifier, which significantly outperforms the standalone filtering algorithms.

  4. Catfish production using intensive aeration

    Science.gov (United States)

    For the last 3 years, researchers at UAPB and NWAC have been monitoring and verifying production yields in intensively aerated catfish ponds with aeration rates greater than 6 hp/acre. We now have three years of data on commercial catfish production in intensively aerated ponds. With stocking densi...

  5. Experimental research on sewage treatment with a concrete eco-membrane biological reactor with micro aeration%微曝气混凝土生态膜法污水处理试验研究

    Institute of Scientific and Technical Information of China (English)

    蒋娜莎; 金腊华

    2011-01-01

    为提高污染物去除效率,在渠式混凝土膜生物反应器内部的部分反应槽中增加间歇性的微曝气,增强反应器的好氧氧化作用;采用连续流运行方式,对实际生活污水进行了污水处理实验.实验结果表明,微曝气混凝土生态膜法的污水处理效率高:CODcx去除率>70%、BOD5去除率>80%、氨氮去除率>75%、总氮和总磷的去除率均>50%,出水水质基本达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)的一级B标准要求.%In order to improve pollutant removal effects,sewage treatment experiments have been made with a homemade channel concrete eco-membrane biological reactor,in which micro aeration is adopted at some bed of the channel to increase intermittent micro aeration and enhance aerobic oxidation of the reactor. Experiments on treating actual sewage are carried out by continuous flowing operations. The results show that the technology of concrete eco-membrane with micro aeration has optimal sewage purification effects,I.e. GODcr removal rate>70% , BOD5 removal rate>80% , ammonia nitrogen removal rate>75% ,and both of total nitrogen and total phosphorus removal rate >50%. The effluent water quality can basically reach the requirements of B standard of the first class of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002).

  6. Investigating the Efficiency of Biological Filters for Ammonia Removal

    Directory of Open Access Journals (Sweden)

    S Motesaddi Zarandi, MR Massoudinejad, A Mazaheri Tehrani, H Pouri

    2013-09-01

    Full Text Available Backgrounds and Aims: Ammonia removal from air to prevent severe damage to the environment and living organisms is very important. Biofiltration is an efficient, easy, cost-effective, and environmentally friendly process for degradation of ammonia from waste air. The aim of this study is to investigate the efficiency of biological filtration using a compost and scallop bed for ammonia removal. Materials and Methods: According to the ammonia removal method a column with 14cm inner diameter and 45cm height made from transparent Plexiglas was used. The column was filled up to 25 cm with compost and scallop (with a scallop: compost ratio of 1:4. In this study, performance of the biofilter was studied under 10 different flow rates (1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 lit/min and 5 different concentrations (0-20, 20-40, 40-60, 60-80 and 80-100 ppm at a temperature of 25 degrees Celsius. Results: The results of this study showed that efficiency is decreased when the flow rate or concentration is increased because the microbial population is reduced. The efficiency was reduced by 84.6-98.2 percent. Maximum efficiency occurred at a 0.19g/(m3.h loading rate. Efficiency was in 0-20 concentration intervals at a flow rate of 1 lit/min and at an Empty Bed Residence Time (EBRT of 240 seconds. Conclusion: The results show that a biofilter with a compost and scallop bed is efficient for ammonia removal from air. Results can be optimized in the design and operation of biological systems to be used in the industrial control of ammonia gas.

  7. [Ecological stability on biological removal of iron and manganese filter under poor nutritional conditions].

    Science.gov (United States)

    Yang, Hong; Xiong, Xiao-Li; Duan, Xiao-Dong; Song, Li-Xin; Yu, Ping-Bo; Li, Wei; Zhang, Jie

    2010-01-01

    To supply necessary bacteria and available nutrients, a method of returning backwashing wastewater to the bio-filter for removal of iron and manganese was used. The ecological stability of bio-filter was investigated from 3 aspects: iron and manganese removal efficiency, micro-ecological characteristics and the quantity distribution of dominant bacteria. The results indicated that, the bio-filter held strong antishock loading capability, when the system was operated at high filtration rate (10-13.9 m/h) and high manganese concentration (3.5-4.5 mg/L), a removal rate more than 98.9% of iron and manganese was achieved. Iron and manganese oxidizing bacteria are the dominant microflora in biological filtering layer, they not only adhere on filter sand materials (4.3 x 10(6) MPN/mL) to form compact biofilm, but also exist among filter materials void (6.5 x 10(6) MPN/mL) to form suspended flocs, which is very important to complete removal of iron and manganese. In the past 5 years, the bio-filter realized a continuous and stable operation and kept a high removal efficiency of iron and manganese without adding any nutrients.

  8. Biological treatment of wastewaters from a dye manufacturing company using a trickling filter

    Energy Technology Data Exchange (ETDEWEB)

    Kornaros, M. [Department of Chemical Engineering, University of Patras, 1 Karatheodori St., 26500 Patras (Greece)]. E-mail: kornaros@chemeng.upatras.gr; Lyberatos, G. [Department of Chemical Engineering, University of Patras, 1 Karatheodori St., 26500 Patras (Greece)

    2006-08-10

    The aim of this work was to assess the effectiveness of a biological trickling filter for the treatment of wastewaters produced by a company manufacturing organic dyes and varnishes. The combined wastewater effluent was fed to a pilot-scale trickling filter in two feeding modes, continuously and as a sequencing batch reactor (SBR). The biodegradability of the diluted wastewaters that were subjected to physicochemical treatment, using Ca(OH){sub 2} and FeSO{sub 4}, was initially studied using a continuously operated trickling filter. The system efficiency ranged up to 60-70% for a hydraulic loading of 1.1 m{sup 3}/m{sup 2} day and up to 80-85% for a hydraulic loading 0.6 m{sup 3}/m{sup 2} day. A stable chemical oxygen demand (COD) removal efficiency of 60-70% was achieved even in the case of undiluted wastewater at a hydraulic loading of 1.1 m{sup 3}/m{sup 2} day. The effectiveness of biological treatment of a mixture of the company's main wastewater streams was also examined. The microorganisms developed in the trickling filter were able to efficiently remove COD levels up to 36,000 mg/L, under aerobic conditions at pH values between 5.5 and 8.0. Depending on the operating conditions of the system, about 30-60% of the total COD removal was attributed to air stripping caused by the air supply at the bottom of the filter, whereas the rest of the COD was clearly removed through biological action. The proposed biological treatment process based on a trickling filter, which was operated either continuously or even better in an SBR mode, appears as a promising pretreatment step for coping with dye manufacturing wastewaters in terms of removing a significant portion of the organic content.

  9. Biological removal of iron and manganese in rapid sand filters - Process understanding of iron and manganese removal

    DEFF Research Database (Denmark)

    Lin, Katie

    .g. flocculation) and physical (e.g. membrane filtration) based technologies. The removal of dissolved manganese and iron is important. If manganese and iron enter the distribution system, the water will become coloured and have a metallic taste, and it may cause problems in the distribution network due......In Denmark and many other European countries, drinking water is exclusively or mainly based on groundwater. Treatment of the groundwater is rather simple, only including aeration and a subsequent filtration process. The filtration process may take place over to steps. Step 1: Filtration in a pre......-filter, where iron is removed. Step 2: Filtration in an after-filter where e.g. ammonium and manganese is removed. The treatment relies on microbial processes and may present an alternative, greener and more sustainable approach for drinking water production spending less chemicals and energy than chemical (e...

  10. Nitrogen and Phosphorus Removal Performance in the Novel Multi-Layered Biological Tricking Filter

    Directory of Open Access Journals (Sweden)

    CUI Ting-ting

    2014-02-01

    Full Text Available Biological trickling filter is one of the main rural sewage treatment technology, but it still has the shortcomings such as lower re-moval efficiency for nitrogen and phosphorus or lower stability. In order to improve the nitrogen and phosphorus removal efficiency of the de-vice and find out its optimum technological conditions, the study took the novel multi-layered biological tricking filter as the device to test the contribution of filter medium, hydraulic loading, recirculation ratio on the treatment of nitrogen and phosphorus removal. The results showed that when the hydraulic loading of 4 m3·m-2·d-1, the recirculation ratio rate of 2∶1 and slag as filter medium were applied, the best effect could be achieved in the filter. The highest mean efficiency of NH4+-N, TN, TP and COD were 87.08%, 57.37%, 66.04% and 80.78%, respectively.The results also indicated that higher recirculation ratio was one of effective paths to improve nitrogen removal efficiency.

  11. Analysis pipeline for the epistasis search – statistical versus biological filtering

    Directory of Open Access Journals (Sweden)

    Xiangqing eSun

    2014-04-01

    Full Text Available Gene-gene interactions may contribute to the genetic variation underlying complex traits but have not always been taken fully into account. Statistical analyses that consider gene-gene interaction may increase the power of detecting associations, especially for low-marginal-effect markers, and may explain in part the missing heritability. Detecting pair-wise and higher-order interactions genome-wide requires enormous computational power. Filtering pipelines increase the computational speed by limiting the number of tests performed. We summarize existing filtering approaches to detect epistasis, after distinguishing the purposes that lead us to search for epistasis. Statistical filtering includes quality control on the basis of single marker statistics to avoid the analysis of bad and least informative data, and limits the search space for finding interactions. Biological filtering includes targeting specific pathways, integrating various databases based on known biological and metabolic pathways, gene function ontology and protein-protein interactions. It is increasingly possible to target single-nucleotide polymorphisms that have defined functions on gene expression, though not belonging to protein-coding genes. Filtering can improve the power of an interaction association study, but also increases the chance of missing important findings.

  12. Biological filter capable of simultaneous nitrification and denitrification for Aquatic Habitat in International Space Station.

    Science.gov (United States)

    Uemoto, H; Shoji, T; Uchida, S

    2014-04-01

    The biological filter capable of simultaneous nitrification and denitrification was constructed for aquatic animal experiments in the International Space Station (ISS). The biological filter will be used to remove harmful ammonia excreted from aquatic animals in a closed water circulation system (Aquatic Habitat). The biological filter is a cylindrical tank packed with porous glass beads for nitrification and dual plastic bags for denitrification. The porous beads are supporting media for Nitrosomonas europaea and Nitrobacter winogradskyi. The N. europaea cells and N. winogradskyi cells on the porous beads, oxidize the excreted ammonia to nitrate via nitrite. On the other hand, the dual bag is composed of an outer non-woven fabric bag and an inner non-porous polyethylene film bag. The outer bag is supporting media for Paracoccus pantotrophus. The inner bag, in which 99.5% ethanol is packed, releases the ethanol slowly, since ethanol can permeate through the non-porous polyethylene film. The P. pantotrophus cells on the outer bag reduce the produced nitrate to nitrogen gas by using the released ethanol as an electron donor for denitrification. The biological filter constructed in this study consequently removed the ammonia without accumulating nitrate. Most of the excess ethanol was consumed and did not affect the nitrification activity of the N. europaea cells and N. winogradskyi cells severely. In accordance with the aquatic animal experiments in the ISS, small freshwater fish had been bred in the closed water circulation system equipped with the biological filter for 90 days. Ammonia concentration daily excreted from fish is assumed to be 1.7 mg-N/L in the recirculation water. Under such conditions, the harmful ammonia and nitrite concentrations were kept below 0.1 mg-N/L in the recirculation water. Nitrate and total organic carbon concentrations in the recirculation water were kept below 5 mg-N/L and 3 mg-C/L, respectively. All breeding fish were alive and ate

  13. Study of 2-D photon crystal Fano slab filters for biological sensing

    Institute of Scientific and Technical Information of China (English)

    QIANG Ze-xuan; QIU Yi-shen; LI Hui; BAI Ji-bo; CHEN Xi-yao

    2009-01-01

    A new compact optical Fano filter suitable for biological sensing is proposed, which patterns photon crystal in single crystalline silicon nanomembranes (SiNMs) and transferring onto transparent glass substrates. The effects of air hole size and silicon thickness on the transmission characteristics of new filter are numerically investigated by using three-dimen-sional finite-difference time-domain (FDTD) technique, the spectral response is also studied by baek-filling bio-liquid. The results show that the dip wavelength will shift toward longer wavelength by either reducing air hole radius or filling bio-liquid. The number of dips will increase with the increase of silicon thickness. The size of proposed filter can be less than 1 mm2.

  14. Energy-filtered transmission electron microscopy of biological samples on highly transparent carbon nanomembranes

    CERN Document Server

    Rhinow, Daniel; Weber, Nils-Eike; Beyer, André; Gölzhäuser, Armin; Kühlbrandt, Werner; Hampp, Norbert; Turchanin, Andrey; 10.1016/j.ultramic.2011.01.028

    2011-01-01

    Ultrathin carbon nanomembranes (CNM) comprising crosslinked biphenyl precursors have been tested as support films for energy-filtered transmission electron microscopy (EFTEM) of biological specimens. Due to their high transparency CNM are ideal substrates for electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) of stained and unstained biological samples. Virtually background-free elemental maps of tobacco mosaic virus (TMV) and ferritin have been obtained from samples supported by ~ 1 nm thin CNM. Furthermore, we have tested conductive carbon nanomembranes (cCNM) comprising nanocrystalline graphene, obtained by thermal treatment of CNM, as supports for cryoEM of ice-embedded biological samples. We imaged ice-embedded TMV on cCNM and compared the results with images of ice-embedded TMV on conventional carbon film (CC), thus analyzing the gain in contrast for TMV on cCNM in a quantitative manner. In addition we have developed a method for the preparation of vitrified specimens, sus...

  15. Landfill aeration in the framework of a reclamation project in Northern Italy.

    Science.gov (United States)

    Raga, Roberto; Cossu, Raffaello

    2014-03-01

    In situ aeration by means of the Airflow technology was proposed for landfill conditioning before landfill mining in the framework of a reclamation project in Northern Italy. A 1-year aeration project was carried out on part of the landfill with the objective of evaluating the effectiveness of the Airflow technology for landfill aerobization, the evolution of waste biological stability during aeration and the effects on leachate and biogas quality and emissions. The main outcomes of the 1-year aeration project are presented in the paper. The beneficial effect of the aeration on waste biological stability was clear (63% reduction of the respiration index); however, the effectiveness of aeration on the lower part of the landfill is questionable, due to the limited potential for air migration into the leachate saturated layers. During the 1-year in situ aeration project approx. 275 MgC were discharged from the landfill body with the extracted gas, corresponding to 4.6 gC/kgDM. However, due to the presence of anaerobic niches in the aerated landfill, approx. 46% of this amount was extracted as CH4, which is higher than reported in other aeration projects. The O2 conversion quota was lower than reported in other similar projects, mainly due to the higher air flow rates applied. The results obtained enabled valuable recommendations to be made for the subsequent application of the Airflow technology to the whole landfill.

  16. Aeration equipment for small depths

    Science.gov (United States)

    Sluše, Jan; Pochylý, František

    2015-05-01

    Deficit of air in water causes complications with cyanobacteria mainly in the summer months. Cyanobacteria is a bacteria that produces poison called cyanotoxin. When the concentration of cyanobacteria increases, the phenomena "algal bloom" appears, which is very toxic and may kill all the organisms. This article describes new equipment for aeration of water in dams, ponds and reservoirs with small depth. This equipment is mobile and it is able to work without any human factor because its control is provided by a GPS module. The main part of this equipment consists of a floating pump which pumps water from the surface. Another important part of this equipment is an aerator where water and air are blended. Final aeration process runs in the nozzles which provide movement of all this equipment and aeration of the water. Simulations of the flow are solved by multiphase flow with diffusion in open source program called OpenFOAM. Results will be verified by an experiment.

  17. Energy-filtered transmission electron microscopy of biological samples on highly transparent carbon nanomembranes

    Energy Technology Data Exchange (ETDEWEB)

    Rhinow, Daniel, E-mail: daniel.rhinow@biophys.mpg.de [Max-Planck-Institute of Biophysics, Department of Structural Biology, Max-von-Laue-Strasse 3, D-60439 Frankfurt (Germany); Bueenfeld, Matthias; Weber, Nils-Eike; Beyer, Andre; Goelzhaeuser, Armin [University of Bielefeld, Department of Physics, Universitaetsstrasse 25, D-33615 Bielefeld (Germany); Kuehlbrandt, Werner [Max-Planck-Institute of Biophysics, Department of Structural Biology, Max-von-Laue-Strasse 3, D-60439 Frankfurt (Germany); Hampp, Norbert [University of Marburg, Department of Chemistry, Hans-Meerwein-Strasse, D-35032 Marburg (Germany); Turchanin, Andrey [University of Bielefeld, Department of Physics, Universitaetsstrasse 25, D-33615 Bielefeld (Germany)

    2011-04-15

    Ultrathin carbon nanomembranes (CNM) comprising crosslinked biphenyl precursors have been tested as support films for energy-filtered transmission electron microscopy (EFTEM) of biological specimens. Due to their high transparency CNM are ideal substrates for electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) of stained and unstained biological samples. Virtually background-free elemental maps of tobacco mosaic virus (TMV) and ferritin have been obtained from samples supported by {approx}1 nm thin CNM. Furthermore, we have tested conductive carbon nanomembranes (cCNM) comprising nanocrystalline graphene, obtained by thermal treatment of CNM, as supports for cryoEM of ice-embedded biological samples. We imaged ice-embedded TMV on cCNM and compared the results with images of ice-embedded TMV on conventional carbon film (CC), thus analyzing the gain in contrast for TMV on cCNM in a quantitative manner. In addition we have developed a method for the preparation of vitrified specimens, suspended over the holes of a conventional holey carbon film, while backed by ultrathin cCNM. -- Research highlights: {yields} We examine ultrathin carbon nanomembranes (CNM) as supports for biological TEM. {yields} CNM comprise crosslinked biphenyl precursors. {yields} CNM supports enable background-free elemental mapping of heavy and light elements. {yields} We perform cryoEM of ice-embedded biological samples on graphene-like conductive CNM.

  18. Wind-powered dugout aeration

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, B. [Alberta Agriculture, Barrhead, AB (Canada); Chang, J. [Engineering Services, Edmonton, AB (Canada)

    1993-12-31

    A review is presented of past and present use of wind power on Alberta farms, concentrating on the merits of wind-powered aeration systems for improving water quality in farm dugouts. Dugout water quality is seriously affected by nutrient-rich sediments causing excessive algae and plant growth. If dissolved oxygen is not maintained anaerobic decomposition begins, resulting in black, smelly water. Aeration assures an adequate level of dissolved oxygen to control taste and odor and maintains good water quality. There are two common means of aerating dugouts from windmills: use of a floating mechanical type aerator, and a bank-mounted windmill and diaphragm-type pump. Bank-mounted windmill aerators were studied as they were considered to have the most potential for aerating dugouts. Windmill monitoring was carried out on a farm near Manning, Alberta using a Koenders windmill (12 blade rotor). Tests showed that the windmill maintained the dissolved oxygen levels near saturation, and averaged ca 1.0 cubic feet of air pumped per minute. Operating pressure was 5 psi, windmill starting speed was 12 km/h wind, and stopping speed was 8 km/h winds. Tests were also carried out on a Breeze-1 windmill, a 3 blade airplane propeller type windmill. The system average 3.3 cubic feet of air per minute, and started at very low wind speeds of 5-8 km/h. 2 figs.

  19. Biological sand filters: low-cost bioremediation technique for production of clean drinking water.

    Science.gov (United States)

    Lea, Michael

    2008-05-01

    Approximately 1.1 billion people in rural and peri-urban communities of developing countries do not have access to safe drinking water. The mortality from diarrheal-related diseases amounts to approximately 2.2 million people each year from the consumption of unsafe water. Most of them are children under 5 years of age-250 deaths an hour from microbiologically contaminated water. There is conclusive evidence that one low-cost household bioremediation intervention, biological sand filters, are capable of dramatically improving the microbiological quality of drinking water. This unit will describe this relatively new and proven bioremediation technology's ability to empower at-risk populations to use naturally occurring biology and readily available materials as a sustainable way to achieve the health benefits of safe drinking water.

  20. Biological sand filters: low-cost bioremediation technique for production of clean drinking water.

    Science.gov (United States)

    Lea, Michael

    2014-05-01

    Approximately 1.1 billion people in rural and peri-urban communities of developing countries do not have access to safe drinking water. The mortality from diarrheal-related diseases amounts to ∼2.2 million people each year from the consumption of unsafe water. Most of them are children under 5 years of age--250 deaths an hour from microbiologically contaminated water. There is conclusive evidence that one low-cost household bioremediation intervention, use of biological sand filters, is capable of dramatically improving the microbiological quality of drinking water. This unit will describe this relatively new and proven bioremediation technology's ability to empower at-risk populations to use naturally occurring biological principles and readily available materials as a sustainable way to achieve the health benefits of safe drinking water.

  1. Methanethiol Removal from Biogas by Biological Conversion in an Anaerobic Biotrickling Filter

    Institute of Scientific and Technical Information of China (English)

    王佳佳; 张卫江; 徐姣

    2015-01-01

    In this study, methanethiol(MT)-degradation bacteria were cultivated by using MT, methanol and trimethylamine as carbon sources under anaerobic conditions. It was found that the batch bacteria used MT and metha-nol as carbon sources grew faster than those used trimethylamine. The enriched bacteria used MT and methanol as the carbon sources were respectively inoculated in different biotrickling filters. The biological conversion performance of MT under anaerobic conditions was investigated in biotrickling filters. The results showed that the performance of the biotrickling filter inoculated with the bacteria enriched using MT was better than that inoculated with the bacteria en-riched using methanol. When the inlet concentration of MT was 0.005vol%(50,ppm), the empty bed residence time was 50 s, pH value was 8.0, and the flow rate of the nutrient solution was 10 L/h, the removal efficiency of MT reached 95.3%. Adding methanol stimulated the growth of the biomass and the degradation of MT, but caused that some bacteria only degrading methanol outcompeted the bacteria only degrading MT. The concentration of sodium bicarbonate in the nutrient solution needed to be controlled lower than 30 g/L, otherwise, it would be harmful to the degradation of MT.

  2. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavi-tation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator,which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emer-gence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects,of both model and prototype,on the basis of error theory. A method to calculate the cavity length be-low aerators was suggested,which considers overall effects of the above men-tioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  3. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    WU JianHua; RUAN ShiPing

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavitation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator, which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emergence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects, of both model and prototype, on the basis of error theory. A method to calculate the cavity length below aerators was suggested, which considers overall effects of the above mentioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  4. 曝气生物过滤反应器的新型挂膜方法%NEW HANGING BIO-MEMBRANE METHOD OF BIOLOGICAL AERATED FILTER

    Institute of Scientific and Technical Information of China (English)

    员军锋; 李善评

    2003-01-01

    介绍了一种新型快速的生物过滤反应器的挂膜方法.实验证明,该方法符合生物膜形成的微生物学原理.采用此种挂膜方法具有挂膜时间短、耐冲击负荷的优点,比目前应用广泛的循环挂膜法优越.

  5. The NYC native air sampling pilot project: using HVAC filter data for urban biological incident characterization.

    Science.gov (United States)

    Ackelsberg, Joel; Leykam, Frederic M; Hazi, Yair; Madsen, Larry C; West, Todd H; Faltesek, Anthony; Henderson, Gavin D; Henderson, Christopher L; Leighton, Terrance

    2011-09-01

    Native air sampling (NAS) is distinguished from dedicated air sampling (DAS) devices (eg, BioWatch) that are deployed to detect aerosol disseminations of biological threat agents. NAS uses filter samples from heating, ventilation, and air conditioning (HVAC) systems in commercial properties for environmental sampling after DAS detection of biological threat agent incidents. It represents an untapped, scientifically sound, efficient, widely distributed, and comparably inexpensive resource for postevent environmental sampling. Calculations predict that postevent NAS would be more efficient than environmental surface sampling by orders of magnitude. HVAC filter samples could be collected from pre-identified surrounding NAS facilities to corroborate the DAS alarm and delineate the path taken by the bioaerosol plume. The New York City (NYC) Native Air Sampling Pilot Project explored whether native air sampling would be acceptable to private sector stakeholders and could be implemented successfully in NYC. Building trade associations facilitated outreach to and discussions with property owners and managers, who expedited contact with building managers of candidate NAS properties that they managed or owned. Nominal NAS building requirements were determined; procedures to identify and evaluate candidate NAS facilities were developed; data collection tools and other resources were designed and used to expedite candidate NAS building selection and evaluation in Manhattan; and exemplar environmental sampling playbooks for emergency responders were completed. In this sample, modern buildings with single or few corporate tenants were the best NAS candidate facilities. The Pilot Project successfully demonstrated that in one urban setting a native air sampling strategy could be implemented with effective public-private collaboration.

  6. A novel bench-scale column assay to investigate site-specific nitrification biokinetics in biological rapid sand filters

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Albrechtsen, Hans-Jørgen

    2013-01-01

    A bench-scale assay was developed to obtain site-specific nitrification biokinetic information from biological rapid sand filters employed in groundwater treatment. The experimental set-up uses granular material subsampled from a full-scale filter, packed in a column, and operated with controlled....../h could easily be determined at 7.5 g NH4+–N/m3 packed sand/h. This assay, with conditions reflecting full-scale observations, and where the biological activity is subject to minimal physical disturbance, provides a simple and fast, yet powerful tool to gain insight in nitrification kinetics in rapid sand...

  7. Dosimetric and Biologic Differences in Flattened and Flattening-Filter-Free Beam Treatment Plans

    CERN Document Server

    Yan, Yue; Bassetti, Michael; Du, Kaifang; Saenz, Daniel; Harari, Paul; Paliwal, Bhudatt R

    2015-01-01

    Purpose: To quantitatively compare the dosimetric and biologic differences in treatment plans from flattened and flattening-filter-free (FFF) beam for three anatomic cancer sites. Methods and Materials: Treatment plans with static intensity-modulated radiotherapy beams and volumetric modulated arc therapy beams were generated for 13 patients for both the flattened beam and the FFF beam of the TrueBeam system. Beam energies of 6 MV and 10 MV were chosen for planning. A total of 104 treatment plans were generated in 13 patients. In order to analyze the biological effectiveness of treatment plans, dose volume histograms (DVH) were utilized. Flattened and FFF beam plans are quantitatively compared. Results: In head and neck cases, for VMAT plans, dose reduction in the FFF beam plans compared to the flattened beam in left cochlea, right submandibular gland and right parotid gland reached up to 2.36 Gy, 1.21 Gy and 1.45 Gy, respectively. Similarly, for static IMRT plans, the dose reduction of the FFF beam plans com...

  8. Degradation of atrazine by microbial consortium in an anaerobic submerged biological filter.

    Science.gov (United States)

    Nasseri, Simin; Baghapour, Mohammad Ali; Derakhshan, Zahra; Faramarzian, Mohammad

    2014-09-01

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) (ATZ) is one of the components of S-triazine. Due to its certain characteristics, ATZ causes pollution in various ecosystems and has been of concern for its probable carcinogenic effects on humans. Researchers have used chemical and physical methods for removing ATZ from the environment. Although these methods are quick, they have not been capable of complete mineralization. Therefore, researchers are looking for methods with lower energy consumption and cost and higher efficiency. In this study, biodegradation of ATZ by microbial consortium was evaluated in the aquatic environment. The present study aimed to evaluate the efficiency of ATZ removal from aqueous environments by using an anaerobic submerged biological filter in four concentration levels of atrazine and three hydraulic retention times. The maximum efficiencies of ATZ and soluble chemical oxygen demand (SCOD) were 51.1 and 45.6%, respectively. There was no accumulation of ATZ in the biofilm and the loss of ATZ in the control reactor was negligible. This shows that ATZ removal in this system was due to biodegradation. Furthermore, the results of modeling showed that the Stover-Kincannon model had desirable fitness (R² > 99%) in loading ATZ in this biofilter.

  9. Reducing and verifying haloacetic acids in treated drinking water using a biological filter system.

    Science.gov (United States)

    Lou, Jie C; Chan, Hung Y; Yang, Chih Y; Tseng, Wei B; Han, Jia Y

    2014-01-01

    This study focused on reducing the haloacetic acid (HAA) concentrations in treated drinking water. HAA has been thought to be one possible nutrient supporting heterotrophic bacteria regrowth in drinking water. In this study, experiments were conducted using a pilot-scale system to evaluate the efficiency of biological filters (BF) for reducing excess HAA concentrations in water. The BF system reduced the total HAA concentration and the concentrations of five HAA species in the water. Dichloroacetic acid (DCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA) were the three main HAA5 species that were present in the treated drinking water in this investigation. Combined, these three species represent approximately 77% of the HAA5 in the finished water after BF. The verification of the empirical HAA equation for the outlet in the BF system indicated linear relationships with high correlation coefficients. The empirical equation for the HAA5 concentrations in the finished water was established by examining other nutrients (e.g., dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm wavelength (UV254), and ammonia nitrogen) that can reduce pathogenic contamination. These findings may be useful for designing advanced processes for conventional water treatment plants or for managing water treatment and distribution systems for providing high-quality drinking water.

  10. Controlling of crustacean zooplankton reproduction in biological activated carbon (BAC) filters by strengthen operation and management of conventional process

    Institute of Scientific and Technical Information of China (English)

    LIU Li-jun; ZHANG Jin-song; LI Xiao-wei; HE Jun-guo

    2010-01-01

    To counter the mass reproduction and penetration of crustacean zooplankton in Biological Activated Carbon (BAC) filters which may result in the presence of organisms in potable water and water pollution,this paper analyzed the factors affecting organisms' reproduction in BAC filters.A comparative study was performed on the density and composition of crustacean zooplankton of the concerned water treatment units of two advanced water plants (Plant A and B) which with the same raw water and the same treatment technique in southern China.The results obtained show that the crustaceans' density and composition was very different between the sand filtered water of Plant A and Plant B.which Harpacticoida bred sharply in the sediment tanks and penetrated sand filter into BAC falters was the primary reason of crustaceans reproduce in BAC filters of Plant A.For prevention of the organisms reproduction in BAC,some strengthen measures was taken including pre-chlorination,cleaning coagulation tanks and sediment tanks completely,increasing sludge disposal frequency to stop organisms enter BAC filters,and the finished water quality was improved and enhanced.

  11. An overview of the analytical methods for the determination of organic ultraviolet filters in biological fluids and tissues

    Energy Technology Data Exchange (ETDEWEB)

    Chisvert, Alberto, E-mail: alberto.chisvert@uv.es [Departamento de Quimica Analitica, Facultad de Quimica, Universitat de Valencia, Doctor Moliner St. 50, 46100 Burjassot, Valencia (Spain); Leon-Gonzalez, Zacarias [Unidad Analitica, Instituto de Investigacion Sanitaria Fundacion Hospital La Fe, 46009 Valencia (Spain); Tarazona, Isuha; Salvador, Amparo [Departamento de Quimica Analitica, Facultad de Quimica, Universitat de Valencia, Doctor Moliner St. 50, 46100 Burjassot, Valencia (Spain); Giokas, Dimosthenis [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece)

    2012-11-08

    Highlights: Black-Right-Pointing-Pointer Papers describing the determination of UV filters in fluids and tissues are reviewed. Black-Right-Pointing-Pointer Matrix complexity and low amounts of analytes require effective sample treatments. Black-Right-Pointing-Pointer The published papers do not cover the study of all the substances allowed as UV filters. Black-Right-Pointing-Pointer New analytical methods for UV filters determination in these matrices are encouraged. - Abstract: Organic UV filters are chemical compounds added to cosmetic sunscreen products in order to protect users from UV solar radiation. The need of broad-spectrum protection to avoid the deleterious effects of solar radiation has triggered a trend in the cosmetic market of including these compounds not only in those exclusively designed for sun protection but also in all types of cosmetic products. Different studies have shown that organic UV filters can be absorbed through the skin after topical application, further metabolized in the body and eventually excreted or bioaccumulated. These percutaneous absorption processes may result in various adverse health effects, such as genotoxicity caused by the generation of free radicals, which can even lead to mutagenic or carcinogenic effects, and estrogenicity, which is associated with the endocrine disruption activity caused by some of these compounds. Due to the absence of official monitoring protocols, there is a demand for analytical methods that enable the determination of UV filters in biological fluids and tissues in order to retrieve more information regarding their behavior in the human body and thus encourage the development of safer cosmetic formulations. In view of this demand, there has recently been a noticeable increase in the development of sensitive and selective analytical methods for the determination of UV filters and their metabolites in biological fluids (i.e., urine, plasma, breast milk and semen) and tissues. The complexity of

  12. Towards advanced aeration modelling: from blower to bubbles to bulk.

    Science.gov (United States)

    Amaral, Andreia; Schraa, Oliver; Rieger, Leiv; Gillot, Sylvie; Fayolle, Yannick; Bellandi, Giacomo; Amerlinck, Youri; Mortier, Séverine T F C; Gori, Riccardo; Neves, Ramiro; Nopens, Ingmar

    2017-02-01

    Aeration is an essential component of aerobic biological wastewater treatment and is the largest energy consumer at most water resource recovery facilities. Most modelling studies neglect the inherent complexity of the aeration systems used. Typically, the blowers, air piping, and diffusers are not modelled in detail, completely mixed reactors in a series are used to represent plug-flow reactors, and empirical correlations are used to describe the impact of operating conditions on bubble formation and transport, and oxygen transfer from the bubbles to the bulk liquid. However, the mechanisms involved are very complex in nature and require significant research efforts. This contribution highlights why and where there is a need for more detail in the different aspects of the aeration system and compiles recent efforts to develop physical models of the entire aeration system (blower, valves, air piping and diffusers), as well as adding rigour to the oxygen transfer efficiency modelling (impact of viscosity, bubble size distribution, shear and hydrodynamics). As a result of these model extensions, more realistic predictions of dissolved oxygen profiles and energy consumption have been achieved. Finally, the current needs for further model development are highlighted.

  13. Landfill aeration for emission control before and during landfill mining.

    Science.gov (United States)

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area.

  14. Design of high efficiency and energy saving aeration device for aquaculture

    Science.gov (United States)

    Liu, Sibo

    2017-03-01

    Energy efficient aeration device for aquaculture, in line with "by more than a generation, dynamic aeration" train of thought for technical design and improvement. Removable aeration terminal as the core, multi-level water to improve the method, the mobile fading pore aeration, intelligent mobile and open and close as the main function, aimed at solving the existing pond aeration efficiency, low energy consumption is high, the function of a single problem. From energy saving, efficiency, biological bacteria on the three directions, the aquaculture industry of energy conservation and emissions reduction. Device of the main advantages are: 1, original mobile fading aerator on the one hand, to expand the scope of work, playing a micro porous aeration of dissolved oxygen with high efficiency and to achieve "by more than a generation", on the other hand, through the sports equipment, stir the mixture of water, the water surface of photosynthesis of plants rich in dissolved oxygen input parts of the tank, compared to the stillness of the aerator can be more fully dissolved oxygen.2, through the opening of the pressure sensor indirect control device, can make the equipment timely and stop operation, convenient in use at the same time avoid the waste of energy.3, the biofilm suspension in aeration terminal, can be accomplished by nitration of microbial multi-level water improvement, still can make biofilm increase rate of netting in the movement process, the biological and mechanical aerobic promote each other, improve the efficiency of both. In addition, the device has small power consumption, low cost of characteristics. And have a certain degree of technical barriers, have their own intellectual property rights, and high degree of product market demand, easily accepted by customers, has a very high popularization value.

  15. Autotrophic Nitrogen Removal in a Membrane-Aerated Biofilm Reactor Under Continuous Aeration: A Demonstration

    DEFF Research Database (Denmark)

    Gilmore, Kevin R.; Terada, Akihiko; Smets, Barth F.

    2013-01-01

    This work describes the successful coupling of partial nitrification (nitritation) and anaerobic ammonium oxidation in a membrane-aerated biofilm reactor (MABR) with continuous aeration. Controlling the relative surface loadings of oxygen versus ammonium prevented complete nitrite oxidation and a...

  16. Radon removal equipment based on aeration: A literature study of tests performed in Sweden between 1981 and 1996

    Energy Technology Data Exchange (ETDEWEB)

    Mjoenes, L

    2000-02-01

    In Sweden some principles to reduce the radon concentration in drinking water were tested in the beginning of the 1980s. Spray aeration under atmospheric pressure, diffused bubble aeration, aeration in the pressure tank and different combinations of these principles were studied. Aeration in the drill hole and adsorption on granulated activated char-coal were also tested. The best results, about 70 % reduction, were obtained with aeration in the pressure tank with a spray system combined with diffused air bubbling. The Oerebro project in the beginning of the 1990s included on site testing of five different aeration solutions: Aeration in the drill hole, aeration in the storage tank, ejector aeration, shallow tray aeration and packed column aeration. The radon removal efficiency varied between 20 % and 99 %. In 1994 a study intended to test the radon removal capacity of different water treatment equipment was performed. Six units of radon separators were included but most of the tested equipment was installed for other water treatment purposes. The performed measurements showed that the only types of equipment that reduce the radon concentration efficiently are radon separators and reverse osmosis filters. The radon removal capacity of the radon separators varied between 23 % and 97 %. In 1996 the nine most common radon separators on the Swedish market were tested. The results showed that the tested radon removal equipment worked well, although the technical quality and chosen technical solutions were not always the best. The radon removal capacity of the units participating in this test was in most cases between 96 and 99 %. In some cases the capacity exceeded 99 %. In order to reach this radon removal capacity the water must be recirculated in a storage tank under atmospheric pressure.

  17. Retention of titanium dioxide nanoparticles in biological activated carbon filters for drinking water and the impact on ammonia reduction.

    Science.gov (United States)

    Liu, Zhiyuan; Yu, Shuili; Park, Heedeung; Liu, Guicai; Yuan, Qingbin

    2016-06-01

    Given the increasing discoveries related to the eco-toxicity of titanium dioxide (TiO2) nanoparticles (NPs) in different ecosystems and with respect to public health, it is important to understand their potential effects in drinking water treatment (DWT). The effects of TiO2 NPs on ammonia reduction, ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in biological activated carbon (BAC) filters for drinking water were investigated in static and dynamic states. In the static state, both the nitrification potential and AOB were significantly inhibited by 100 μg L(-1) TiO2 NPs after 12 h (p  0.05). In the dynamic state, different amounts of TiO2 NP pulses were injected into three pilot-scale BAC filters. The decay of TiO2 NPs in the BAC filters was very slow. Both titanium quantification and scanning electron microscope analysis confirmed the retention of TiO2 NPs in the BAC filters after 134 days of operation. Furthermore, the TiO2 NP pulses considerably reduced the performance of ammonia reduction. This study identified the retention of TiO2 NPs in BAC filters and the negative effect on the ammonia reduction, suggesting a potential threat to DWT by TiO2 NPs.

  18. A 96-well screen filter plate for high-throughput biological sample preparation and LC-MS/MS analysis.

    Science.gov (United States)

    Peng, Sean X; Cousineau, Martin; Juzwin, Stephen J; Ritchie, David M

    2006-01-01

    A novel 96-well screen filter plate (patent pending) has been invented to eliminate a time-consuming and labor-intensive step in preparation of in vivo study samples--to remove blood or plasma clots. These clots plug the pipet tips during a manual or automated sample-transfer step causing inaccurate pipetting or total pipetting failure. Traditionally, these blood and plasma clots are removed by picking them out manually one by one from each sample tube before any sample transfer can be made. This has significantly slowed the sample preparation process and has become a bottleneck for automated high-throughput sample preparation using robotic liquid handlers. Our novel screen filter plate was developed to solve this problem. The 96-well screen filter plate consists of 96 stainless steel wire-mesh screen tubes connected to the 96 openings of a top plate so that the screen filter plate can be readily inserted into a 96-well sample storage plate. Upon insertion, the blood and plasma clots are excluded from entering the screen tube while clear sample solutions flow freely into it. In this way, sample transfer can be easily completed by either manual or automated pipetting methods. In this report, three structurally diverse compounds were selected to evaluate and validate the use of the screen filter plate. The plasma samples of these compounds were transferred and processed in the presence and absence of the screen filter plate and then analyzed by LC-MS/MS methods. Our results showed a good agreement between the samples prepared with and without the screen filter plate, demonstrating the utility and efficiency of this novel device for preparation of blood and plasma samples. The device is simple, easy to use, and reusable. It can be employed for sample preparation of other biological fluids that contain floating particulates or aggregates.

  19. Ammonia-based feedforward and feedback aeration control in activated sludge processes.

    Science.gov (United States)

    Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

    2014-01-01

    Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

  20. Development of a model for activated sludge aeration systems: linking air supply, distribution, and demand.

    Science.gov (United States)

    Schraa, Oliver; Rieger, Leiv; Alex, Jens

    2017-02-01

    During the design of a water resource recovery facility, it is becoming industry practice to use simulation software to assist with process design. Aeration is one of the key components of the activated sludge process, and is one of the most important aspects of modelling wastewater treatment systems. However, aeration systems are typically not modelled in detail in most wastewater treatment process modelling studies. A comprehensive dynamic aeration system model has been developed that captures both air supply and demand. The model includes sub-models for blowers, pipes, fittings, and valves. An extended diffuser model predicts both oxygen transfer efficiency within an aeration basin and pressure drop across the diffusers. The aeration system model allows engineers to analyse aeration systems as a whole to determine biological air requirements, blower performance, air distribution, control valve impacts, controller design and tuning, and energy costs. This enables engineers to trouble-shoot the entire aeration system including process, equipment and controls. It also allows much more realistic design of these highly complex systems.

  1. Purging dissolved oxygen by nitrogen bubble aeration

    Science.gov (United States)

    Yamashita, Tatsuya; Ando, Keita

    2016-11-01

    We apply aeration with nitrogen microbubbles to water in order to see whether oxygen gas originally dissolved in the water at one atmosphere is purged by the aeration. The concentration of dissolved oxygen (DO) is detected by a commercial DO meter. To detect the dissolved nitrogen (DN) level, we observe the growth of millimetre-sized bubbles nucleated at glass surfaces in contact with the aerated water and compare it with the Epstein-Plesset theory that accounts for DO/DN diffusions and the presence of the glass surfaces. Comparisons between the experiment and the theory suggest that the DO in the water are effectively purged by the aeration.

  2. A novel 3D wavelet based filter for visualizing features in noisy biological data

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; Haase, S; Lyle, J M; Agard, D A; Sedat, J W

    2005-01-05

    We have developed a 3D wavelet-based filter for visualizing structural features in volumetric data. The only variable parameter is a characteristic linear size of the feature of interest. The filtered output contains only those regions that are correlated with the characteristic size, thus denoising the image. We demonstrate the use of the filter by applying it to 3D data from a variety of electron microscopy samples including low contrast vitreous ice cryogenic preparations, as well as 3D optical microscopy specimens.

  3. Aeration of the teuftal landfill: Field scale concept and lab scale simulation.

    Science.gov (United States)

    Ritzkowski, Marco; Walker, Beat; Kuchta, Kerstin; Raga, Roberto; Stegmann, Rainer

    2016-09-01

    Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration

  4. Reduction of COD and Turbidity of Effluent in the Swine Productions Unit Employing Anaerobic Baffled Reactor (ABR Followed by Biological Filters and Sand Filter

    Directory of Open Access Journals (Sweden)

    Euzebio Beli

    2010-04-01

    Full Text Available The growing swine production is constantly in conflict with the environment due to the lack of environmental management directed to the cycle of animal production and the industrial sector, mainly due to the mishandling of slurry produced. In association with large concentrations of confined animals appear huge dumps of organic matter, inorganic nutrients and gaseous emissions, which require special care for its disposal to the environment. The aim of this study was to evaluate the use of an anaerobic baffled reactor (ABR in series with two downflow biological filters, followed by a sand filter as a polishing treatment. It were analyzed the reduction of COD and turbidity, and the behavior of pH in all phases of treatment. The removal of COD in the conjugated system, which occurred during treatment ranged from 74.55% to 94.41% with an average removal of 84.24%. In turn, the removal of turbidity from the period ranged from 53.07% to 96.11% with an average removal of 85.49%. In the studied period the pH changed from 5,6 to 8,4. This system was efficient in the removal of COD and turbidity of swine wastewater.

  5. 曝气生物滤池不同滤料高度除污性能分析%Decontamination Performance Analysis of Different Filter Material Height in the Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    李传龙; 杨纪伟; 李思敏; 赵静霄; 唐振芳

    2012-01-01

    在水力负荷为5m/h,汽水比为1~2的条件下,在曝气生物滤池(BAF)正常稳定运行时,对曝气生物滤池不同滤料层高度的除污性能进行研究分析.实验结果表明:曝气生物滤池对浊度、COD、NH4+-N及色度的去除均有不错的去除效果.并且浊度、COD、色度的去除主要发生在滤料高度为0~50cm处,而NH4+-N的去除主要发生在滤料高度的50~90cm处.

  6. Relating dynamic conditions to the performance of biological rapid sand filters used to remove ammonium, iron, and manganese from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.;

    and media samples were collected throughout the depth of the column and over the operational cycle of the columns. Substrate analysis included ammonium, nitrite, nitrate, iron, and manganese. Qpcr analysis were also performed to quantify ammonium oxidizing bacteria (AOBs), ammonium oxidizing archea ( AOAs...... on the roles of both Ammonium oxidizing bacteria (AOBs) and Ammonium oxidizing archea (AOAs) in the biological removal of ammonium in rapid sand filters and how varying substrate loadings and operating conditions can affect the biological performance of these filters....

  7. Biologically induced deposition of fine suspended particles by filter-feeding bivalves in land-based industrial marine aquaculture wastewater.

    Directory of Open Access Journals (Sweden)

    Yi Zhou

    Full Text Available Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67 ± 0.99 cm and M. galloprovincialis (shell height: 4.43 ± 0.98 cm was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1 • d(-1, respectively. The total solid suspension (TSS deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P < 0.001. Furthermore, organic matter and C, N in the sediments of bivalve treatments were significantly lower than those in the sediments of the control (P < 0.05. It was suggested that the filter feeders C. gigas and M. galloprovincialis had considerable potential to filter and accelerate the deposition of suspended particles from industrial aquaculture wastewater, and simultaneously yield value-added biological products.

  8. 硝酸处理对竹炭曝气生物滤池性能的影响%The Influence of Nitric Acid Modification on Aerated Bio-filter with Bamboo Charcoal as Carriers

    Institute of Scientific and Technical Information of China (English)

    罗舒君

    2015-01-01

    以硝酸处理竹炭作为曝气生物滤池填料,通过研究硝酸处理对竹炭吸附性能、表面官能团等的影响,考查硝酸处理竹炭对反应器性能的影响.结果表明,硝酸处理后竹炭表面含氧官能团增加,有利于微生物的附着,仅4d就完成挂膜, 反应器对有机负荷具有良好的去除能力, 在COD负荷为1.8和4.8 kg/(m3·d) 时, 平均去除率分别为83.3%和79.4%.%In this study, the influence of nitric acid modification on the adsorption performance and the surface functional groups of the bamboo charcoal was investigated. After that, the modified bamboo charcoal was employed as the bio-filter for wastewater treatment to study its performance on dealing with organic matter. The results indicated that the nitric acid modification increased surface oxygen functional groups of bamboo charcoal. The modification also promoted the growing of the microorganism, and shortened the mature period of bio-film to 4 days. The reactor was good at COD treatment. On condition that COD volume loaded of system was 1.8 and 4.8 kg/(m3·d), the removal efficiency can reached to 83.3%and 79.4%, respectively.

  9. Sistema com aeração, decantação e filtragem para a melhoria da qualidade de água em irrigação localizada System with aeration, sedimentation and filtering for the improving of water quality in drip irrigation

    Directory of Open Access Journals (Sweden)

    Marco A. F. Lemos Filho

    2011-06-01

    Full Text Available A qualidade da água é muito importante para irrigação por gotejamento, pois ela escoa por pequenos bocais dos emissores, podendo ocorrer obstrução devido à deposição dos sólidos em suspensão. Portanto, antes da instalação do projeto, devem-se avaliar parâmetros de qualidade da água, para adotar medidas preventivas, evitando o risco de entupimento do sistema. Este trabalho teve como objetivo avaliar um sistema composto por aeradores com aspersores, sobre leito de pedra, para a precipitação dos íons Fe+2e Mn+2 em tanque de decantação, e um conjunto de filtragem composto por três filtros de areia e um de disco, em sistema de irrigação localizada. O trabalho foi realizado na Fazenda Alvorada, no município de Nova Granada - SP, no período de março a outubro de 2008. Foram realizadas determinações de variáveis físicas e químicas da água, ao longo do sistema de aeração, decantação e filtragem, o qual foi eficiente para a melhoria da qualidade de água, reduzindo os níveis de risco de entupimento de severo para médio e de médio para baixo. Oxigênio dissolvido, condutividade elétrica, pH, Fe+2e Fe+3 não diferenciaram a qualidade de água entre os pontos do sistema de tratamento, porém a turbidez, sólidos dissolvidos, sólidos em suspensão, ferro total e manganês total reduziram-se significativamente pelo uso do sistema proposto, melhorando a qualidade da água.Water quality is very important to drip irrigation, as it flows in small diameter holes, and may cause obstruction due to deposition of solid matter. Whence the water must be evaluated before installation of the project. Parameters related to water quality are essential to define conducting measures to avoid the risk of clogging the system. This study aimed to evaluate a system with sprinklers aeration on bedrock, for Fe+2and Mn total precipitation in sedimentation tank and a set of filtering consisting of three sand filters and a disk, installed in

  10. Biological filters: their applications and yields; Filtros biologicos: sus aplicaciones y rendimientos

    Energy Technology Data Exchange (ETDEWEB)

    Barcelon, S.; Terrasa Diaz, M.; Frau Gene, C. [Empresa Municipal de Aguas Alcantarillado, S.A., Mallorca (Spain)

    1995-06-01

    The system of filtering gases resulting from the treatment of urban residual waters, by the compost substrate and obtaining more than acceptable yields, is presented in this article from the point of view of getting to know certain possible application, as well as the evolution of the substrate condition over time. (Author) 6 refs.

  11. HYDRAULIC RESEARCH OF AERATORS ON TUNNEL SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

    RUAN Shi-ping; WU Jian-hua; WU Wei-wei; XI Ru-ze

    2007-01-01

    The selection of the configuration and size of an aerator was of importance for a tunnel spillway under the conditions of high speed flows. Experimental investigations were conducted on the effects of entrained air on the tunnel spillway in the Goupitan Project, based on the criterion of gravity similarity and the condition of aerated flow velocity of over 6 m/s, with physical models. The configurations of the aerators were presented of a larger bottom air concentration, to protect the tunnel spillway from cavitation as well as to see no water fills in the grooves.

  12. Modelisation of the contribution of sediments in the treatment process case of aerated lagoons.

    Science.gov (United States)

    Jupsin, H; Vasel, J L

    2007-01-01

    In aerated lagoons and even more in stabilization ponds the specific power (W/m3) is not high enough to maintain all the suspended solids in suspension. Some part of the suspended solids (including biomass) settles directly into the reactor and not in the final settling pond. The gradual accumulation of those sediments on the pond bottom affects performance by reducing the pond volume and shortening the Hydraulic Residence Time. However, the role played by these deposits is not restricted to such a physical effect. Far from being inert sediments they are also an important oxygen sink that must be taken into account when designing aerator power and oxygen supply, for example. On the other hand, under aerobic conditions, the upper layer of sediments may contribute to the treatment as a biofilm compartment in the reactor. In aerated lagoon systems another process contributes to the interaction of deposits and the liquid phase: the operating (often sequencing) of aerators may induce a drastic resuspension of deposits. In a 3,000 m3 aerated lagoon we evaluated that 3 tons of deposits were resuspended when aerators were started. Due to those processes we consider that a mathematical model of an aerated lagoon or of a stabilization pond has to take into account the contribution (positive and negative aspects) of deposits in the process. In this paper we propose a model for sediments including production but also biological processes. Simulations of the aerated lagoon with or without the "sediment compartment" demonstrate the effect and the importance of this compartment on the process. Of course a similar approach could be used for facultative or even maturation ponds. The next step would be to include anaerobic activities in the bottom layer.

  13. Control of the aeration volume in an activated sludge process for nitrogen removal.

    Science.gov (United States)

    Samuelsson, P; Carlsson, B

    2002-01-01

    Biological nitrogen removal in an activated sludge process is obtained by two biological processes; nitrification and denitrification. Nitrifying bacteria need dissolved oxygen and a sufficiently large aeration volume for converting ammonium to nitrate in the wastewater. The objective of this paper is to develop an automatic control strategy for adjusting the aerated volume so that the effluent ammonium level can be kept close to a desired value despite major changes in the influent load. The strategy is based on applying exact linearization of the IAWO Activated Sludge Process Model No 1. Simulation results show that the suggested controller effectively attenuates process disturbances.

  14. Biologically induced deposition of fine suspended particles by filter-feeding bivalves in land-based industrial marine aquaculture wastewater.

    Science.gov (United States)

    Zhou, Yi; Zhang, Shaojun; Liu, Ying; Yang, Hongsheng

    2014-01-01

    Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67 ± 0.99 cm) and M. galloprovincialis (shell height: 4.43 ± 0.98 cm) was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1) • d(-1), respectively. The total solid suspension (TSS) deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P aquaculture wastewater, and simultaneously yield value-added biological products.

  15. FAF-Drugs2: Free ADME/tox filtering tool to assist drug discovery and chemical biology projects

    Directory of Open Access Journals (Sweden)

    Miteva Maria A

    2008-09-01

    Full Text Available Abstract Background Drug discovery and chemical biology are exceedingly complex and demanding enterprises. In recent years there are been increasing awareness about the importance of predicting/optimizing the absorption, distribution, metabolism, excretion and toxicity (ADMET properties of small chemical compounds along the search process rather than at the final stages. Fast methods for evaluating ADMET properties of small molecules often involve applying a set of simple empirical rules (educated guesses and as such, compound collections' property profiling can be performed in silico. Clearly, these rules cannot assess the full complexity of the human body but can provide valuable information and assist decision-making. Results This paper presents FAF-Drugs2, a free adaptable tool for ADMET filtering of electronic compound collections. FAF-Drugs2 is a command line utility program (e.g., written in Python based on the open source chemistry toolkit OpenBabel, which performs various physicochemical calculations, identifies key functional groups, some toxic and unstable molecules/functional groups. In addition to filtered collections, FAF-Drugs2 can provide, via Gnuplot, several distribution diagrams of major physicochemical properties of the screened compound libraries. Conclusion We have developed FAF-Drugs2 to facilitate compound collection preparation, prior to (or after experimental screening or virtual screening computations. Users can select to apply various filtering thresholds and add rules as needed for a given project. As it stands, FAF-Drugs2 implements numerous filtering rules (23 physicochemical rules and 204 substructure searching rules that can be easily tuned.

  16. DESIGN INFORMATION ON FINE PORE AERATION SYSTEMS

    Science.gov (United States)

    Field studies were conducted over several years at municipal wastewater treatment plants employing line pore diffused aeration systems. These studies were designed to produce reliable information on the performance and operational requirements of fine pore devices under process ...

  17. EMERGENCE ANGLE OF FLOW OVER AN AERATOR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Aerator is an important device for release works of hydraulic structures with high-speed flow in order to protect them from cavitation damage. This kind of protecting effect is related closely to cavity length below the aerator, while the cavity length is dominated by the emergence angle over the aerator. Therefore it is crucial to determine this angle accurately. In the present paper the affecting intensities of flow depth and the fluctuating velocity on this angle were analyzed through two introduced parameters. Furthermore, the improved expressions of emergence angle estimation, for both ramp-type and step-type aerators, were presented by means of 68 sets of experimental data from 6 projects based on error theory. The results showed that the present method has higher accuracy than the previously reported methods.

  18. Oxygen transfer in circular surface aeration tanks.

    Science.gov (United States)

    Rao, Achanta Ramakrishna; Patel, Ajey Kumar; Kumar, Bimlesh

    2009-06-01

    Surface aeration systems employed in activated sludge plants are the most energy-intensive units of the plants and typically account for a higher percentage of the treatment facility's total energy use. The geometry of the aeration tank imparts a major effect on the system efficiency. It is said that at optimal geometric conditions, systems exhibits the maximum efficiency. Thus the quantification of the optimal geometric conditions in surface aeration tanks is needed. Optimal geometric conditions are also needed to scale up the laboratory result to the field installation. In the present work, experimental studies have been carried out on baffled and unbaffled circular surface aeration tanks to ascertain the optimal geometric conditions. It is found that no optimal geometric conditions exist for the liquid/water depth in circular surface aeration tanks; however, for design purposes, a standard value has been assumed. Based on the optimal geometric conditions, a scale-up equation has been developed for the baffled circular surface aeration tanks.

  19. Landfill aeration within the scope of post-closure care and its completion.

    Science.gov (United States)

    Ritzkowski, Marco; Stegmann, Rainer

    2013-10-01

    The time frame required for post-closure care of Municipal Solid Waste (MSW) landfills is often assessed over several decades or centuries. One possibility to significantly shorten this period and, at the same time, improve the emission behavior exists with in situ aeration. Positive effects in connection with this method for biological stabilization have been investigated and published elsewhere. However, until today neither generally accepted monitoring guidelines nor completion criteria have been defined. With the paper on hand the authors propose a methodology for the assessment of both, total and remaining stabilization periods for aerated landfills. The central component of this methodology is a carbon balance. The latter is based on a detailed waste characterization in combination with online monitoring of the emissions (gas and leachate). The methodology is exemplarily demonstrated by means of data derived from a full scale project in Northern Germany. Here it could be shown that the predicted aeration period of approximately 6.4years was sufficient to bio-stabilize the landfill. Furthermore, proposals for the completion of landfill aeration are presented. In this connection, carbon balance is of particular importance since the amount of biodegradable organic carbon mainly determines the emission potential. Additional parameters, aiming at a validation of the state of biological stabilization achieved during aeration are proposed and described.

  20. Influence of air flow rate and backwashing on the hydraulic behaviour of a submerged filter.

    Science.gov (United States)

    Cobos-Becerra, Yazmin Lucero; González-Martínez, Simón

    2013-01-01

    The aim of this study was to evaluate backwashing effects on the apparent porosity of the filter media and on the hydraulic behaviour of a pilot scale submerged filter, prior to biofilm colonization, under different hydraulic retention times, and different air flow rates. Tracer curves were analysed with two mathematical models for ideal and non-ideal flow (axial dispersion and Wolf and Resnick models). The filter media was lava stones sieved to 4.5 mm. Backwashing causes attrition of media particles, decreasing the void volume of the filter media and, consequently, the tracer flow is more uniform. The eroded media presented lower dead volumes (79% for the filter with aeration and 8% for the filter without aeration) compared with the new media (83% for the filter with aeration and 22% for the filter without aeration). The flow patterns of eroded and new media were different because the more regular shape of the particles decreases the void volume of the filter media. The dead volume is attributed, in the case of the filter with aeration, to the turbulence caused by the air bubbles that generate preferential channelling of the bulk liquid along the filter media, creating large zones of stagnant liquid and, for the filter without aeration, to the channels formed due to the irregular shaped media.

  1. Evaluation of aerated biofilter systems for microbial methane oxidation of poor landfill gas.

    Science.gov (United States)

    Haubrichs, R; Widmann, R

    2006-01-01

    In the long-term, landfills are producing landfill gas (LFG) with low calorific values. Therefore, the utilization of LFG in combined heat and power plants (CHP) is limited to a certain period of time. A feasible method for LFG treatment is microbial CH(4) oxidation. Different materials were tested in actively aerated lab-scale bio-filter systems with a volume of 0.167 m(3). The required oxygen for the microbial CH(4) oxidation was provided through perforated probes, which distributed ambient air into the filter material. Three air input levels were installed along the height of the filter, each of them adjusted to a particular flow rate. During the tests, stable degradation rates of around 28 g/(m(3) h) in a fine-grained compost material were observed at a CH(4) inlet concentration of 30% over a period of 148 days. Compared with passive (not aerated) tests, the CH(4) oxidation rate increased by a factor of 5.5. Therefore, the enhancement of active aeration on the microbial CH(4) oxidation was confirmed. At a O(2)/CH(4) ratio of 2.5, nearly 100% of the CH(4) load was decomposed. By lowering the ratio from 2.5 to 2, the efficiency fell to values from 88% to 92%. By varying the distribution to the three air input levels, the CH(4) oxidation process was spread more evenly over the filter volume.

  2. AERATION OF THE ICE-COVERED WATER POOLS USING THE WAVE FLOW AERATOR

    Directory of Open Access Journals (Sweden)

    Solomin E.E

    2013-12-01

    Full Text Available This article describes the technical advantages and economic benefits of the ice-covered pool aeration plants consuming power from renewable energy sources. We made a comparative evaluation of the wave flow-aeration method and other methods of pool aeration. We showed the indexes and the characteristics of the wave flow-maker for aeration of ice-covered pools on the territory of Russia. We also made calculations of the economic benefits of aeration plants using the devices converting renewable energy. The project can be scaled and extended to the territory of the CIS, Europe, USA and Canada in the changing climate conditions and the variety of feed reservoirs around the world.

  3. Impact of titanium dioxide nanoparticles on the bacterial communities of biological activated carbon filter intended for drinking water treatment.

    Science.gov (United States)

    Zhiyuan, Liu; Shuili, Yu; Heedeung, Park; Qingbin, Yuan; Guicai, Liu; Qi, Li

    2016-08-01

    Titanium dioxide nanoparticles (TiO2 NPs) are inevitably present in the aquatic environment owing to their increasing production and use. However, knowledge of the potential effects of TiO2 NPs on the treatment of drinking water is scarce. Herein, the effects of two types of anatase TiO2 NPs (TP1, 25 nm; TP2, 100 nm) on the bacterial community in a biological activated carbon (BAC) filter were investigated via quantitative polymerase chain reaction (Q-PCR) analysis, ATP quantification, and 454 pyrosequencing analysis. Both TP1 and TP2 significantly inhibited the bacterial ATP level (p < 0.01) and induced a decrease in the abundance of bacterial 16S rDNA gene copies at doses of 0.1 and 100 mg L(-1). Simultaneously, the diversity and evenness of the bacterial communities were considerably reduced. The relative abundances of bacteria annotated to OTUs from Nitrospira class and Betaproteobacteria class decreased upon TiO2 NP treatment, whereas those of Bacilli class and Gammaproteobacteria class increased. TiO2 NP size showed a greater effect on the bacterial composition than did the dose based on Bray-Curtis distances. These findings identified negative effects of TiO2 NPs on the bacterial community in the BAC filter. Given the fact that BAC filters are used widely in drinking water treatment plants, these results suggested a potential threat by TiO2 NP to drinking water treatment system.

  4. Hydrolytic anaerobic reactor and aerated constructed wetland systems for municipal wastewater treatment - HIGHWET project.

    Science.gov (United States)

    Pascual, A; de la Varga, D; Arias, C A; Van Oirschot, D; Kilian, R; Álvarez, J A; Soto, M

    2017-01-01

    The HIGHWET project combines the hydrolytic up-flow sludge bed (HUSB) anaerobic digester and constructed wetlands (CWs) with forced aeration for decreasing the footprint and improving effluent quality. The HIGHWET plant in A Coruña (NW of Spain) treating municipal wastewater consists of a HUSB and four parallel subsurface horizontal flow (HF) CWs. HF1, HF2 and HF3 units are fitted with forced aeration, while the control HF4 is not aerated. All the HF units are provided with effluent recirculation, but different heights of gravel bed (0.8 m in HF1 and HF2, and 0.5 m in HF3 and HF4) are implemented. Besides, a tobermorite-enriched material was added in the HF2 unit in order to improve phosphorus removal. The HUSB 76-89% of total suspended solids (TSS) and about 40% of chemical oxygen demand (COD) and biological oxygen demand (BOD). Aerated HF units reached above 96% of TSS, COD and BOD at a surface loading rate of 29-47 g BOD5/m(2)·d. An aeration regime ranging from 5 h on/3 h off to 3 h on/5 h off was found to be adequate to optimize nitrogen removal, which ranged from 53% to 81%. Average removal rates of 3.4 ± 0.4 g total nitrogen (TN)/m(2)·d and 12.8 ± 3.7 g TN/m(3)·d were found in the aerated units, being 5.5 and 4.1 times higher than those of the non-aerated system. The tobermorite-enriched HF2 unit showed a distinct higher phosphate (60-67%) and total phosphorus (54%) removal.

  5. Phosphate limitation in biological rapid sand filters used to remove ammonium from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Albrechtsen, Hans-Jørgen; Smets, Barth F.;

    2013-01-01

    Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification c...... the total number of ammonium oxidizing bacteria in the column. © 2013 American Water Works Association AWWA WQTC Conference Proceedings All Rights Reserved....

  6. Soil Aeration deficiencies in urban sites

    Science.gov (United States)

    Weltecke, Katharina; Gaertig, Thorsten

    2010-05-01

    Soil aeration deficiencies in urban sites Katharina Weltecke and Thorsten Gaertig On urban tree sites reduction of soil aeration by compaction or sealing is an important but frequently underestimated factor for tree growth. Up to 50% of the CO2 assimilated during the vegetation period is respired in the root space (Qi et al. 1994). An adequate supply of the soil with oxygen and a proper disposal of the exhaled carbon dioxide are essential for an undisturbed root respiration. If the soil surface is smeared, compacted or sealed, soil aeration is interrupted. Several references show that root activity and fine root growth are controlled by the carbon dioxide concentration in soil air (Qi et al.1994, Burton et al. 1997). Gaertig (2001) found that decreasing topsoil gas permeability leads to reduced fine root density and hence to injury in crown structure of oaks. In forest soils a critical CO2 concentration of more than 0.6 % indicates a bad aeration status (Gaertig 2001). The majority of urban tree sites are compacted or sealed. The reduction of soil aeration may lead to dysfunctions in the root space and consequently to stress during periods of drought, which has its visible affects in crown structure. It is reasonable to assume that disturbances in soil aeration lead to reduced tree vigour and roadworthiness, resulting in high maintenance costs. The assessment of soil aeration in urban sites is difficult. In natural ecosystems the measurement of gas diffusivity and the gas-chromatical analysis of CO2 in soil air are accepted procedures in analyzing the state of aeration (Schack-Kirchner et al. 2001, Gaertig 2001). It has been found that these methods can also be applied for analyzing urban sites. In particular CO2 concentration in the soil atmosphere can be considered as a rapidly assessable, relevant and integrating indicator of the aeration situation of urban soils. This study tested the working hypothesis that soil aeration deficiencies lead to a decrease of fine

  7. FLOW REGIMES BELOW AERATORS FOR DISCHARGE TUNNELS

    Institute of Scientific and Technical Information of China (English)

    MA Fei; WU Jian-hua

    2012-01-01

    The flow regimes below an aerator influence directly the air entrainment and the cavitation damage control.Based on the theoretical considerations,the experiments of the aerator for a discharge tunnel were conducted,and the relationships between the flow regime and hydraulic and geometric parameters were investigated.The results showed that,there are two kinds of threshold values for the flow regime conversions.One is Fr1-2 standing for the conversion from the fully filled cavity to the partially filled cavity,and the other is Fr2-3 which shows the change from the partially filled cavity to the net air cavity.Two empirical expressions were obtained for the conversions of the flow regimes,which can be used in the designs of the aerators.

  8. Sawdust discharge rate from aerated hoppers

    Institute of Scientific and Technical Information of China (English)

    Pan Chen; Zhulin Yuan; Chien-Song Chyang; Fu-Xiong Zhuan

    2011-01-01

    This paper presents a numerical and experimental study of the discharge rate of sawdust from an aerated hopper as an important parameter in many industrial processes involving the handling of other granular materials. Numerical experiments are conducted by means of an Eulerian-Eulerian approach coupled with the kinetic theory of granular flow (KTGF). Emphasis is given to the effects of particle size, hopper outlet width, hopper half angle, aeration height and air flow rate. The results show that the discharge rate is significantly affected by hopper outlet width, particle size and air flow rate, but is not sensitive to the hopper half angle and aeration height: increasing hopper outlet width or air flow rate increases discharge rate, while increasing particle size decreases discharge rate. Close agreement between numerical predictions and experimental results is obtained.

  9. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

    Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat......Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different...

  10. PRESSURE CHARACTERISTICS OF CAVITATION CONTROL BY AERATION

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; LU Yang-quan; JU Wen-jie; CAI Xin-ming; DING Chun-sheng

    2005-01-01

    This experimental investigation was systematically conducted with the aid of a non-circulating water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology in China.The test velocity is between 20m/s and 40m/s.The least air concentration to prevent cavitation erosion lies between 1.7% and 4.5%.Pressure waveforms with and without aeration in cavitation and cavitation erosion regions were measured.Time-averaged pressure profiles with and without aeration were compared.Pressure characteristics corresponding to least air concentration to prevent cavitation erosion in cavitation and cavitation erosion regions were analyzed.

  11. Effect of biostimulation on biodegradation of dissolved organic carbon in biological granular activated carbon filters

    Directory of Open Access Journals (Sweden)

    K. Tihomirova

    2012-03-01

    Full Text Available The addition of labile organic carbon (LOC to enhance the biodegradation rate of dissolved organic carbon (DOC in biological columns was studied. Acetate standard solution (NaAc and LB (Luria Bertrani medium were used as LOC as biostimulants in glass column system used for measurements of biodegradable dissolved organic carbon (BDOC. The addition of LOC related with the increase of total DOC in sample. The concentration of BDOC increased up to 7 and 5 times and was utilized after 24 min. contact time. The biodegradation rate constant was increased at least 8 times during adaptation-biostimulation period. There was a strong positive correlation between the biodegradation rate constant and the concentration of BDOC. Biostimulation period ranged from 24 to 53 h for NaAc biostimulant and from 20 to 168 h for LB. The study has shown that LOC could be used as stimulator to enhance the biodegradation rate of DOC during biofiltration.

  12. Effect of biostimulation on biodegradation of dissolved organic carbon in biological filters

    Directory of Open Access Journals (Sweden)

    K. Tihomirova

    2012-07-01

    Full Text Available The addition of labile organic carbon (LOC to enhance the biodegradation rate of dissolved organic carbon (DOC in biological columns was studied. Acetate standard solution (NaAc and Luria Bertrani (LB medium were used as LOC as biostimulants in glass column system used for measurements of biodegradable dissolved organic carbon (BDOC. The addition of LOC related with the increase of total DOC in sample. The concentration of BDOC increased up to 7 and 5 times and was utilized after 24 min. contact time. The biodegradation rate constant was increased at least 26 times during adaptation-biostimulation period. There was a strong positive correlation between the biodegradation rate constant and the concentration of BDOC. Biostimulation period ranged from 24 to 53 h for NaAc biostimulant and from 20 to 168 h for LB. The study has shown that LOC could be used as stimulator to enhance the biodegradation rate of DOC during biofiltration.

  13. Package plant of extended aeration membrane bioreactors: a study on aeration intensity and biofouling control.

    Science.gov (United States)

    Ujang, Z; Ng, S S; Nagaoka, H

    2005-01-01

    Biofouling control is important for effective process of membrane bioreactor (MBR). In this study, phenomena of biofouling for immersed type extended aeration MBR with two different anti-fouling aeration intensities were studied through a laboratory set up. The objectives of this study were (a) to observe biofouling phenomena of MBR that operates under different anti-fouling bubbling intensity, and simultaneously monitors performance of the MBR in organic carbon and nutrients removal; (b) to compare effectiveness of detergent and detergent-enzyme cleaning solutions in recovering biofouled membranes that operated in the extended aeration MBR. For MBR, which operated under continuous anti-fouling aeration, deposition and accumulation of suspended biomass on membrane surface were prohibited. However, flux loss was inescapable that biofilm layer was the main problem. Membrane cleaning was successfully carried out with detergent-enzyme mixture solutions and its effectiveness was compared with result from cleaning with just detergent solution.

  14. Aerated bunker discharge of fine dilating powders

    NARCIS (Netherlands)

    Ouwerkerk, C.E.D.; Molenaar, H.J.; Frank, M.J.W.

    1992-01-01

    The discharge rate of coarse powders (mean particle size 500 ¿m) from bunkers without aeration can be described by both empirical relations and theoretical models. In the case of small particles the discharge rate is largely overestimated. As the powder dilates during flow a negative pressure gradie

  15. Soil Aeration Variability as Affected by Reoxidation

    Institute of Scientific and Technical Information of China (English)

    A.WOLI(N)SKA; Z.ST(E)PNIEWSKA

    2013-01-01

    The interplay between soil physical parameters during the recovery from anoxic stresses (reoxidation) is largely unrecognized.This study was conducted to characterise the soil aeration status and derive correlations between variable aeration factors during reoxidation.Surface layers (0-30 cm) of three soil types,Haplic Phaeozem,Mollic Gleysol,and Eutric Cambisol (FAO soil group),were selected for analysis.The moisture content was determined for a range of pF values (0,1.5,2.2,2.7,and 3.2),corresponding to the available water for microorganisms and plant roots.The variability of a number of soil aeration parameters,such as water potential (pF),air-filled porosity (Eg),oxygen diffusion rate (ODR),and redox potential (Eh),were investigated.These parameters were found to be interrelated in most cases.There were significant (P < 0.001) negative correlations of pF,Eg,and ODR with Eh.A decrease in water content as a consequence of soil reoxidation was manifested by an increase in the values of aeration factors in the soil environment.These results contributed to understanding of soil redox processes during recovery from flooding and might be useful for development of agricultural techniques aiming at soil reoxidation and soil fertility optimisation.

  16. Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Zhou; Yuanyuan Wu; Hanchang Shi; Yanqing Song

    2013-01-01

    Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant (WWTP) is meaningful for the optimization of WWTP,however,scarce to best of our knowledge.Through analyzing a plug flow aeration tank in the Lucun WWTP,in Wuxi,China,the oxygenation capacity of fine-bubble aerators under process conditions have been measured insitu using the off-gas method and the non-steady-state method.The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP had significantly different oxygen transfer performance; furthermore,the aerators in the same corridor shared almost equal oxygen transfer performance over the course of a day.Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water.The loss of oxygen transfer coefficient was over 50% under low-aeration conditions (aeration amount < 0.67 Nm3/hr).However,as the aeration amount reached 0.96 Nm3/hr,the discrepancy of oxygen transfer between the process condition and clean water was negligible.The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

  17. Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant.

    Science.gov (United States)

    Zhou, Xiaohong; Wu, Yuanyuan; Shi, Hanchang; Song, Yanqing

    2013-02-01

    Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant (WWTP) is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. Through analyzing a plug flow aeration tank in the Lucun WWTP, in Wuxi, China, the oxygenation capacity of fine-bubble aerators under process conditions have been measured in-situ using the off-gas method and the non-steady-state method. The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP ha d significantly different oxygen transferperformance; furthermore, the aerators in the samecorridor shared almost equal oxygen transfer performance over the course of a day. Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water. The loss of oxygen transfer coefficient was over 50% under low-aeration conditions (aeration amount aeration amount reached 0.96 Nm3/hr, the discrepancy of oxygen transfer between the process condition and clean water was negligible. The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

  18. Factors Affecting the Oxygenation Capacity of Disc Aerators in an Oxidation Ditch System

    Directory of Open Access Journals (Sweden)

    Abdel E. Ghaly

    2011-01-01

    Full Text Available Problem statement: The use of aerobic biological methods for the treatment of livestock wastes has resulted in a proliferation of mechanical aeration devices to accomplish the desired treatment. The oxidation ditch system with disc aerators is among the aerobic systems that have been used to treat livestock waste. The main objectives of this study were to investigate the effects of various disc design parameters and system operational parameters on the oxygen transfer coefficient and to study the physical phenomenon of oxygen transfer using high speed movie techniques. Approach: A bench-scale oxidation ditch with a disc aerator was used to conduct a series of experiments to determine the effects of immersion depth (2.5-7.5 cm, disc speed (50-250 rpm, disc thickness (0.32-2.55 cm, hole diameter (0.00-1.92 cm and number of rotating discs (1-2 on the oxygen transfer coefficient. The unsteady state method with sodium sulfite oxidation was used to deoxygenate the water and the dissolved oxygen concentration was measured with time. Results: The disc speed had the most significant effect on KLa with the immersion depth and hole diameter both showing strong effects and the disc thickness showing less effect. The effect of adding a second disc was comparable to using a single disc of double the thickness at lower speeds while at speeds higher than 200 rpm doubling the thickness of a single disc had less effect than a second disc. Conclusion: The highest oxygen transfer (1.526 min-1 was achieved using two coaxial discs with a disc speed of 250 rpm, a disc thickness of 0.64 cm, a hole diameter of 1.92 cm and an immersion depth of 7.5 cm. Bubble aeration and eddy aeration were the most prevalent mechanisms of oxygen transfer in the oxidation ditch while surface aeration played a relatively small role in oxygen transfer.

  19. Effect of intermittent aeration strategies on treatment performance and microbial community of an IFAS reactor treating municipal waste water.

    Science.gov (United States)

    Singh, Nitin Kumar; Bhatia, Akansha; Kazmi, Absar Ahmad

    2017-01-31

    This study investigated the effect of various intermittent aeration (IA) cycles on organics and nutrient removal, and microbial communities in an integrated fixed-film activated sludge (IFAS) reactor treating municipal waste water. Average effluent biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids, total nitrogen (TN) and total phosphorus (TP) values were noted as 20, 50, 30, 12 and 1.5 mgL(-1), respectively, in continuous aeration mode. A total of four operational conditions (run 1, continuous aeration; run 2, 150/30 min aeration on/off time; run 3, 120/60 min aeration on/off time and run 4, 90/60 min aeration on/off time) were investigated in IFAS reactor assessment. Among the all examined IA cycles, IA phase 2 gave the maximum COD and BOD removals with values recorded as 97% and 93.8%, respectively. With respect to nutrient removal (TN and TP), IA phase 1 was found to be optimum. Pathogen removal efficiency of present system was recorded as 90-95% during the three phases. With regard to settling characteristics, pilot showed poor settling during IA schedules, which was also evidenced by high sludge volume index values. Overall, IA could be used as a feasible way to improve the overall performance of IFAS system.

  20. The effect of aeration and recirculation on a sand-based hybrid constructed wetland treating low-strength domestic wastewater.

    Science.gov (United States)

    Zapater-Pereyra, M; Kyomukama, E; Namakula, V; van Bruggen, J J A; Lens, P N L

    2016-08-01

    The Duplex-constructed wetland (CW) is a hybrid system composed of a vertical flow (VF) CW on top of a horizontal flow filter (HFF). Each compartment is designed to play a different role: aerobic treatment in the VF CW due to intermittent feeding and anoxic treatment in the HFF due to saturated conditions. Three Duplex-CWs were used in this study: Control, Aerated and Recirculating. The role of each compartment was tested for pollutant removal and micro-invertebrate abundance. In all systems, the VF CW removed mainly organic matter, solids and NH4(+)-N. Pathogens were removed in both compartments. Likewise, total nitrogen removal occurred in both compartments, only the Recirculating HFF was not able to denitrify the nitrogen due to the slightly more oxic conditions as compared to the other systems. All systems met discharge guidelines for organic matter, but only the Control and Aerated systems met those for total nitrogen. At the applied loading rates, the pollutant removal was not significantly enhanced by the use of aeration and recirculation. Therefore, operation as in the Control system, without aeration or recirculation, is recommended for the tested Duplex-CWs. If artificial aeration will be used in CWs, the support material should be carefully selected to allow a proper air distribution.

  1. CFD model of an aerating hydrofoil

    Science.gov (United States)

    Scott, D.; Sabourin, M.; Beaulieu, S.; Papillon, B.; Ellis, C.

    2014-03-01

    Improving water quality in the tailrace below hydroelectric dams has become a priority in many river systems. In warm climates, water drawn by the turbine from deep in a reservoir can be deficient in dissolved oxygen (DO), a critical element in maintaining a healthy aquatic ecosystem. Many different solutions have been proposed in order to increase the DO levels in turbine discharge, including: turbine aeration systems (adding air to the water through either the turbine hub, the periphery or through distributed aeration in the runner blades); bubble diffusers in the reservoir or in the tailrace; aerating weirs downstream of the dams; and surface water pumps in the reservoir near the dam. There is a significant potential to increase the effectiveness of these solutions by improving the way that oxygen is introduced into the water; better distributions of bubbles will result in better oxygen transfer. In the present study, a two-phase Computational Fluid Dynamics model has been formulated using a commercial code to study the distribution of air downstream of a simple aerating hydrofoil. The two-phase model uses the Eulerian-Eulerian approach. Appropriate relations are used to model the interphase forces, including the Grace drag force model, the Favre averaged drag force and the Sato enhanced eddy viscosity. The model is validated using experimental results obtained in the water tunnel at the University of Minnesota's Saint Anthony Falls Laboratory. Results are obtained for water velocities between 5 and 10 m/s, air flow rates between 0.5 and 1.5 sL/min and for angles of attack between 0° and -8°. The results of this study show that the CFD model provides a good qualitative comparison to the experimental results by well predicting the wake location at the different flow rates and angles of attack used.

  2. Cavity filling water control below aerator devices

    Institute of Scientific and Technical Information of China (English)

    钱尚拓; 吴建华; 马飞; 徐建荣; 彭育; 汪振

    2014-01-01

    With the rapid development of high dam projects within China, the dragon-drop-tail spillway tunnel is introduced and widely used. In view of the high water head and the large flow velocity on the dragon-drop-tail section, aerator devices are usually placed for the cavitation damage control. For the device placed in its initial position, it is a serious concern to design a suitable flow regime of the cavity and to control the cavity filling water due to the large flow depth and the low Froude number through this aera-tor. In this study, the relationships between the geometries of the aerator device and the jet impact angle of the lower trajectory of the flow are theoretically analyzed with/without a local slope. Nine test cases with different geometries are designed, the effectiveness of the filling water control is experimentally investigated under different operation conditions, and two criteria of the local slope design are proposed. It is concluded that the cavity flow regime and the filling water can be improved if a small impact angle and some sui-table geometries of the local slope are designed.

  3. Supersonic Injection of Aerated Liquid Jet

    Science.gov (United States)

    Choudhari, Abhijit; Sallam, Khaled

    2016-11-01

    A computational study of the exit flow of an aerated two-dimensional jet from an under-expanded supersonic nozzle is presented. The liquid sheet is operating within the annular flow regime and the study is motivated by the application of supersonic nozzles in air-breathing propulsion systems, e.g. scramjet engines, ramjet engines and afterburners. The simulation was conducted using VOF model and SST k- ω turbulence model. The test conditions included: jet exit of 1 mm and mass flow rate of 1.8 kg/s. The results show that air reaches transonic condition at the injector exit due to the Fanno flow effects in the injector passage. The aerated liquid jet is alternately expanded by Prandtl-Meyer expansion fan and compressed by oblique shock waves due to the difference between the back (chamber) pressure and the flow pressure. The process then repeats itself and shock (Mach) diamonds are formed at downstream of injector exit similar to those typical of exhaust plumes of propulsion system. The present results, however, indicate that the flow field of supersonic aerated liquid jet is different from supersonic gas jets due to the effects of water evaporation from the liquid sheet. The contours of the Mach number, static pressure of both cases are compared to the theory of gas dynamics.

  4. Performance and completion assessment of an in-situ aerated municipal solid waste landfill - Final scientific documentation of an Austrian case study.

    Science.gov (United States)

    Hrad, Marlies; Huber-Humer, Marion

    2016-08-23

    By converting anaerobic landfills into a biologically stabilized state through accelerating aerobic organic matter degradation, the effort and duration necessary for post-closure procedures can be shortened. In Austria, the first full-scale application of in-situ landfill aeration by means of low pressure air injection with simultaneous off-gas collection and treatment was implemented on an old MSW-landfill and operated between 2007 and 2013. Besides complementary laboratory investigations, which included waste sampling from the landfill site prior to aeration start, a comprehensive field monitoring program was conducted to assess the influence of the aeration measure on the emission behavior of the landfilled waste during the aeration period as well as after aeration completion. Although the initial waste material was described as rather stable, the lab-scale aeration tests indicated a significant improvement of the leachate quality and even the biological solid waste stability. However, the aeration success was less pronounced for the application at the landfill site, mainly due to technical limitations in the full-scale operation. In this paper main performance data of the field investigation are compared to four other scientifically documented case studies along with stability indicators for solid waste and leachate characteristics in order to evaluate the success of aeration as well as the progress of a landfill towards completion and end of post-closure care. A number of quantitative benchmarks and relevant context information for the performance assessment of the five hitherto conducted international aeration projects are proposed aiming to support the systematization and harmonization of available results from diverse field studies and full-scale applications in future.

  5. Effects of aeration method and aeration rate on greenhouse gas emissions during composting of pig feces in pilot scale.

    Science.gov (United States)

    Jiang, Tao; Li, Guoxue; Tang, Qiong; Ma, Xuguang; Wang, Gang; Schuchardt, Frank

    2015-05-01

    The aim of this study was to uncover ways to mitigate greenhouse gas (GHG) emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates (0, 0.18, 0.36, and 0.54 L/(kg dry matter (dm)·min)) and methods (continuous and intermittent) on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7:1. The composting process lasted for 10 weeks, and the compost was turned approximately every 2 weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses, but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration, the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36 days.

  6. Inverse problem of bottom slope design for aerator devices

    Institute of Scientific and Technical Information of China (English)

    吴建华; 樊博; 许唯临

    2013-01-01

    Air entrainment is an effective approach to protect release works from cavitation damage. The traditional method of aera-tor device designs is that, for given flow conditions, the geometries of the aerator device are designed and then the effects are experi-mentally tested for cavitation damage control. The present paper proposes an inverse problem method of determining the bottom slopes in front of and behind an aerator if the requirements of air entrainment, flow conditions and some of aerator geometric para-meters are given. An RBF neural network model is developed and the relevant bottom slopes are calculated in different conditions of flow and geometry on the basis of the data of 19 aerator devices from different discharge tunnels with safe operation. The case study shows that the methodology provides an effective way to design aerator devices under given target conditions.

  7. Research on the treatment of synthetic detergent wastewater by using hybrid biological aerated filter%复合曝气生物滤池处理合成洗涤剂废水研究

    Institute of Scientific and Technical Information of China (English)

    罗杰; 纪桂霞; 刘弦; 万博

    2010-01-01

    利用复合式曝气生物滤池(HBAF)处理合成洗涤剂废水,研究了水力负荷、气水比及滤层厚度对其处理性能的影响.结果表明,随着水力负荷的提高,COD、LAS的去除率迅速减小;最佳气水比为4:1;处理出水的COD、LAS浓度与相应的滤层高度之间存在指数关系.在水力负荷为1.1 m3/(m2·h),气水比为4:1的运行条件下,废水流经2 000 mm的滤层后,COD、LAS去除率分别为86%、81%,出水COD、LAS均能达到排放标准.

  8. Study on the biological aerated filter used for treating bean wastewater with spongy iron and argil granules%海绵铁和陶粒填料曝气生物滤池处理豆制品废水

    Institute of Scientific and Technical Information of China (English)

    葛伟青; 王益民; 刘艳娟; 王守伟

    2008-01-01

    针对废水在好氧阶段具有返色的特点,设计了用曝气生物滤池替代活性炭过滤处理豆制品加工废水的深度处理工艺,进行了填料的筛选试验,同时试验研究了在海绵铁与陶粒混合质量比为1:3、HRT=1.0 h时其对CODCr和色度的去除效果.研究表明:曝气生物滤池对CODCr、色度的去除率均能达到40%以上,运行效果稳定.并得出了向海绵铁中加入陶粒可有效地避免填料板结的结论.

  9. DEGRADATION OF ORGANIC SUBSTANCES IN OIL FIELD WASTEWATER BY BIOLOGICAL AERATED FILTER%曝气生物滤池处理采油废水过程中有机物的降解

    Institute of Scientific and Technical Information of China (English)

    赵昕; 倪晋仁

    2007-01-01

    在曝气生物滤池(BAF)系统中,按水力停留时间(HRT)4h,对盐度为0.5% (W/V)的采油废水进行处理,并利用GC-MS对废水中有机物的构成进行分析,结果表明:采油废水中有机污染物的主要构成是9种支链烷烃和18种直链烷烃,分布范围从正十三烷(C13H28)到正三十二烷(C32H66).由于降解中间产物的累积,出水中烷烃类物质所占比例降低,而芳香族物质比例上升.在采油废水中烷烃的存在下, PAHs中最易被微生物降解的是含有4个苯环、脂溶性强的,降解效率达98.0%;而降解效果最差的为含有二个苯环、脂溶性较差的萘,降解效率仅为66.4%.

  10. 沸石-陶粒BAF处理微污染水源水的影响因素研究%On the influencing factors of zeolite-ceramics biological aerated filter (BAF) in treating slightly polluted raw water

    Institute of Scientific and Technical Information of China (English)

    刘金香; 娄金生; 陈春宁

    2007-01-01

    探讨沸石-陶粒BAF工艺对微污染水源水中CODMn、氨氮、UV254、浊度等污染物质的去除效果.通过模型试验,研究了填料高度、水力负荷、气水比等因素对沸石-陶粒曝气生物滤池(BAF)工艺处理效果的影响.结果表明,在水力负荷为1.2~4.8 m3/(m2·h)、气水比为1时,CODMn、氨氮、UV254和浊度的去除率随填料层高度的增加而增加,其中CODMn、UV254、浊度的去除在最初的440 mm内最为显著,而氨氮的去除在220~440 mm范围内较明显; 在气水比为1,水力负荷分别为1.2 m3/(m2·h)、2.4 m3/(m2·h)和4.8 m3/(m2·h)时,CODMn的总去除率分别为38.62%、32.23%和25.37%,较合适的水力负荷为1.2 m3/(m2·h); 在水力负荷为1.2 m3/(m2·h)、气水比由0.5增为1时,CODMn的平均去除率由26.34%增为36.31%,氨氮的平均去除率由78.15%增为94.4%,当气水比增大为2时,CODMn、氨氮的去除率增加很少,合适的气水比为1.研究表明,沸石-陶粒BAF工艺处理微污染水源水的效果良好,且所需的填料高度小,气水比低.

  11. 沸石-陶粒曝气生物滤池处理微污染水源水试验%Test of treatment of slightly polluted source water by zeolite-ceramics biological aerated filter

    Institute of Scientific and Technical Information of China (English)

    刘金香; 娄金生; 陈春宁

    2005-01-01

    采用沸石-陶粒曝气生物滤池,对以有机物和氨氮为主要污染物的微污染水源水进行了处理试验,结果表明:沸石-陶粒曝气生物滤池对微污染水的处理效果较好,在水力停留时间为15~60min,气水体积比为1,水温为17~26℃时,CODMn,NH3-N,UV254的平均去除率分别为32.25%,92.57%,9.73%.气水比、进水有机物负荷对沸石-陶粒曝气生物滤池的运行效果有一定的影响.

  12. Experiment on screening of suitable filler for detergent wastewater treated by biological aerated filter%BAF处理洗涤剂废水适宜填料的筛选试验研究

    Institute of Scientific and Technical Information of China (English)

    许行翔; 纪桂霞; 杨继柏; 周步轩; 司大伟

    2013-01-01

    通过生物陶粒、稀土瓷砂、普通陶粒对洗涤剂废水中难达标的LAS、TP的吸附与生物挂膜实验,结果表明,3种填料对LAS、TP的吸附等温式符合Langmuir模型.生物陶粒对LAS、Tp的吸附去除率分别达到23.2%、27.2%,比稀土瓷砂、普通陶粒有更好的吸附性能,且对污水中污染物LAS、TP的浓度变化有很好的适应性,耐污染冲击负荷性能高于稀土瓷砂、普通陶粒,生物陶粒挂膜速度快,挂膜后处理水的COD达54 mg/L< 60 mg/L,对COD处理效果好.因此,生物陶粒适于呈碱性洗涤剂废水的处理,是BAF处理洗涤剂废水的适宜填料.生物陶粒用作BAF填料处理洗涤剂废水,能有效提高COD、LAS和TP的去除率,使洗涤剂废水能处理达排放标准,这对于保护水环境具有重要意义.%Through the experiments of bio-ceramic,rare earth porcelain sand,normal-ceramic adsorption of LAS,TP in detergent wastewater and handing bio-film,the results show that the three kinds of fillers adsorption isotherm on LAS,TP conform to Langmuir model.The adsorption removal rate of bio-ceramic on LAS,TP reaches 23.2%,27.2% respectively,bio-ceramic has better adsorption properties than rare earth porcelain sand and normal-ceramic,and has very good adaptability on the changes of LAS and TP concentration,bio-ceramic has stronger pollution impact load resistant performance and quick speed of bio-film forming,The COD dilution is 54mg/L witch is less then 60 mg/L after bio-membrane hanging.Bio-ceramic has good treatment effect on COD.Therefore,bio-ceramic is a suitable filler to BAF treatment for the alkaline detergent wastewater.Bio-ceramic used as BAF to treat detergent wastewater can efficiently improve the removal rate of COD、LAS and TP and make the treatment of detergent wastewater meet the blowoff standard,witch is important to the protection of water environment.

  13. 曝气生物滤池用于处理小城镇生活污水的试验研究%Study on Domestic Sewage Treatment by Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    卜发平

    2012-01-01

    Sea cucumbers belong to Echinodemata, Holothuroidea. As marine benthic organisms, they must have their own immune mecha nisms to survive in the environment with high concentrations of microbial pathogens. As an echinoderm species, sea cucumbers lack an adap tive immune system. Their key defenses against foreign (non-self) entities are cellular and humoral immune responses. Sea cucumber coelo mocytes eliminate invaded microorganisms or foreign particles through phagocytosis, encapsulation and release of humoral factors. In this pa per, the studies on sea cucumber immune mechanism were reviewed.%[目的]研究曝气滤池对小城镇生活污水的处理效果.[方法]采集小城镇污水水样,以生物曝气滤池法进行处理,监测NH3-N、TN、TP和COD的含量变化.[结果]生物滤池对小城镇生活污水的处理效果良好,特别是良好的COD去除效果,在进水NH3-N、TN、TP和COD分别为9.7~68.9 mg/L,18.1~73.2 mg/L,1.79~8.78 mg/L,170~336 mg/L时,生物滤池对NH3 -N、TN、TP、COD的平均去除率可分别达到85.9%、61.4%、76.7%和89.2%,其中出水COD达到一级A类标准(GB 18918-2002),出水NH3 -N、TN、TP总体达到一级B类标准.同时研究显示,日处理量的提高有利于提高出水水质,特别是对出水TN、TP有明显的改善效果;但进水浓度过高不利于提高出水水质.[结论]生物曝气滤池可用于小城镇生活污水的处理,能够达到或优于排放标准,且经济高效.

  14. Intensification of ammonia removal from waste water in biologically active zeolitic ion exchange columns.

    Science.gov (United States)

    Almutairi, Azel; Weatherley, Laurence R

    2015-09-01

    The use of nitrification filters for the removal of ammonium ion from waste-water is an established technology deployed extensively in municipal water treatment, in industrial water treatment and in applications such as fish farming. The process involves the development of immobilized bacterial films on a solid packing support, which is designed to provide a suitable host for the film, and allow supply of oxygen to promote aerobic action. Removal of ammonia and nitrite is increasingly necessary to meet drinking water and discharge standards being applied in the US, Europe and other places. Ion-exchange techniques are also effective for removal of ammonia (as the ammonium ion) from waste water and have the advantage of fast start-up times compared to biological filtration which in some cases may take several weeks to be fully operational. Here we explore the performance of ion exchange columns in which nitrifying bacteria are cultivated, with the goal of a "combined" process involving simultaneous ion-exchange and nitrification, intensified by in-situ aeration with a novel membrane module. There were three experimental goals. Firstly, ion exchange zeolites were characterized and prepared for comparative column breakthrough studies for ammonia removal. Secondly effective in-situ aeration for promotion of nitrifying bacterial growth was studied using a number of different membranes including polyethersulfone (PES), polypropylene (PP), nylon, and polytetra-fluoroethylene (PTFE). Thirdly the breakthrough performance of ion exchange columns filled with zeolite in the presence of aeration and in the presence of nitrifying bacteria was determined to establish the influence of biomass, and aeration upon breakthrough during ammonium ion uptake. The methodology adopted included screening of two types of the naturally occuring zeolite clinoptilolite for effective ammonia removal in continuous ion-exchange columns. Next, the performance of fixed beds of clinoptilolite in the

  15. Research on Purification of Domestic Sewage by Artificially Strengthened Ecological Filter Bed in North China

    Institute of Scientific and Technical Information of China (English)

    Yue; SHEN

    2013-01-01

    Artificially strengthened filter bed is an innovative wastewater treatment technology based on the coupling of eco-contact oxidation filters and artificial wetlands purification mechanism.By small scale laboratory equipment,the effects of cascade aeration,filter type,filter clogging and other ecological factors on the operation effect of artificial filter bed were studied.As indicated by the results,the pretreatment of cascade aeration had obvious effect and could satisfy the oxygen requirements of artificially strengthened ecological filter bed.Through the analysis on the purification results of volcanic and gravel filter,the effluent quality of volcanic filter was better than that of gravel filter.With the advantages of low operations costs and good effluent quality,the artificially strengthened ecological filter bed has great value to be popularized in North China.

  16. Estimation of the role of global biological filters in the geochemical migration of trace elements in the ocean: The marginal filter of the ocean

    Science.gov (United States)

    Demina, L. L.

    2011-07-01

    A quantitative estimate has been made for the contribution of biological processes to accumulation and transformation of the trace elements in the marginal biofilter of the ocean. It has been demonstrated that the proportion of phytoplankton having the largest biomass reaches 96-99% of the total mass of trace elements accumulated by biota. The mass of trace elements taken up by bivalved mollusks is tens to hundreds of times less than this, while that by macrophytes is an order of magnitude less than the latter. A dynamic parameter of the biogenic migration, namely the duration of the biological cycle of phytoplankton, has been calculated; this value does not exceed 2-3 days for Zn, Ni, Cu, Cd, Pb, Co, Fe, and Mn. First the trace metal balance in the whole body of mussels Mytilus spp. between the soft tissues and shells was calculated based on their weight proportion (0.1 and 0.9, correspondingly). As a result it was revealed that carbonate shells serve a great reservoir of Mn, Fe, Co, Ni, Cu and As and biomineralization is an important process in their bioaccumulation. The suggested new approach can be applied when making environmental and geochemical estimates of biotic self-purification of water bodies and when using shells as mineral supplements.

  17. Treatment of sewage sludge in a thermophilic membrane reactor (TMR) with alternate aeration cycles.

    Science.gov (United States)

    Collivignarelli, Maria Cristina; Castagnola, Federico; Sordi, Marco; Bertanza, Giorgio

    2015-10-01

    The management of sewage sludge is becoming a more and more important issue, both at national and international level, in particular due to the uncertain recovery/disposal future options. Therefore, it is clear that the development of new technologies that can mitigate the problem at the source by reducing sludge production is necessary, such as the European Directive 2008/98/EC prescribes. This work shows the results obtained with a thermophilic membrane reactor, for processing a biological sludge derived from a wastewater treatment plant (WWTP) that treats urban and industrial wastewater. Sewage sludge was treated in a thermophilic membrane reactor (TMR), at pilot-scale (1 m(3) volume), with alternate aeration cycles. The experimentation was divided into two phases: a "startup phase" during which, starting with a psychrophilic/mesophilic biomass, thermophilic conditions were progressively reached, while feeding a highly biodegradable substrate; the obtained thermophilic biomass was then used, in the "regime phase", to digest biological sludge which was fed to the plant. Good removal yields were observed: 64% and 57% for volatile solids (VS) and total COD (CODtot), respectively, with an average hydraulic retention time (HRT) equal to 20 d, an organic loading rate (OLR) of about 1.4-1.8 kg COD m(-3) d(-1) and aeration/non aeration cycles alternated every 4 h.

  18. OXIDATION OF AS(III) BY AERATION AND STORAGE

    Science.gov (United States)

    A study of the effects of aeration and storage on the oxidation of arsenic(III) was undertaken at three utilities in the US to establish the engineering significance of aeration as a potential pre-treatment method for arsenic removal. The results of this study clearly establish t...

  19. Enhancement of ultrasonic disintegration of sewage sludge by aeration.

    Science.gov (United States)

    Zhao, He; Zhang, Panyue; Zhang, Guangming; Cheng, Rong

    2016-04-01

    Sonication is an effective way for sludge disintegration, which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of sludge. But high energy consumption limits the wide application of sonication. In order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption, aeration was introduced. Results showed that sludge disintegration efficiency was improved significantly by combining aeration with ultrasound. The aeration flow rate, gas bubble size, ultrasonic density and aeration timing had impacts on sludge disintegration efficiency. Aeration that used in later stage of ultrasonic irradiation with low aeration flow rate, small gas bubbles significantly improved ultrasonic disintegration sludge efficiency. At the optimal conditions of 0.4 W/mL ultrasonic irradiation density, 30 mL/min of aeration flow rate, 5 min of aeration in later stage and small gas bubbles, ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was saved. This approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge.

  20. Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of heterogeneous catalytic ozonation and biological process.

    Science.gov (United States)

    Zhuang, Haifeng; Han, Hongjun; Jia, Shengyong; Hou, Baolin; Zhao, Qian

    2014-08-01

    Advanced treatment of biologically pretreated coal gasification wastewater (CGW) was investigated employing heterogeneous catalytic ozonation integrated with anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) process. The results indicated that catalytic ozonation with the prepared catalyst (i.e. MnOx/SBAC, sewage sludge was converted into sludge based activated carbon (SBAC) which loaded manganese oxides) significantly enhanced performance of pollutants removal by generated hydroxyl radicals. The effluent of catalytic ozonation process was more biodegradable and less toxic than that in ozonation alone. Meanwhile, ANMBBR-BAF showed efficient capacity of pollutants removal in treatment of the effluent of catalytic ozonation at a shorter reaction time, allowing the discharge limits to be met. Therefore, the integrated process with efficient, economical and sustainable advantages was suitable for advanced treatment of real biologically pretreated CGW.

  1. Two-phase flow simulation of aeration on stepped spillway

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiangju; LUO Lin; ZHAO Wenqian; LI Ran

    2004-01-01

    Stepped spillways have existed as escape works for a very long time. It is found that water can trap a lot of air when passing through steps and then increasing oxygen content in water body, so stepped spillways can be used as a measure of re-aeration and to improve water quality of water body. However, there is no reliable theoretical method on quantitative calculation of re-aeration ability for the stepped spillways. By introducing an air-water two-phase flow model, this paper used k-ε turbulence model to calculate the characteristic variables of free-surface aeration on stepped spillway. The calculated results fit with the experimental results well. It supports that the numerical modeling method is reasonable and offers firm foundation on calculating re-aeration ability of stepped spillways. The simulation approach can provide a possible optimization tool for designing stepped spillways of more efficient aeration capability.

  2. EFFECT OF AERATOR ON HYDRAULIC DRAG ACTING ON A CHUTE

    Institute of Scientific and Technical Information of China (English)

    NI Han-gen; LI Xin; ZHOU Jing; JIN Qiao

    2005-01-01

    The formulae used to calculate the friction in the non-uniform flow chute were examined with the experimental data, and the results show that the accuracy of the formula is enough for engineering applications. A comparison between the results of friction respectively from the uniform flow assumption and the non-uniform flow approximation indicates that the former is an order of magnitude larger than the latter in the case of steep chute. The hydraulic drag on a steep chute with aerators was measured on the hydraulic model directly and the coefficient of the aerator effect on the drag was obtained. The variation patterns of the wall shear just downstream of the aerators were investigated and the mechanism of the increase in the drag by aerator were analyzed qualitatively with the measured water-depths just downstream the aerators.

  3. 新型组合式分层生物滴滤池启动性能研究%Performance of novel multi-layered biological filter in early operation

    Institute of Scientific and Technical Information of China (English)

    张文坤; 欧阳矜盈; 潘劫皓; 李旭东; 邱江平; 唐利

    2013-01-01

    The performance in treating sewage and the characteristics of biofilm were both studied in multi-layered biological filter and bio-trickling filter.The results showed that the effluent water quality could be achieved stability faster in multi-layered biological filter.Moreover,the removal efficiency and activity of biofilm in multi-layered biological filter were higher than that in bio-trickling filter.Compared with bio-trickling filter,the multi-layered biological filter was illustrated more advantages on pollutants removal.%考察了组合式分层生物滴滤池与普通生物滴滤池在相同条件运行初期污水处理效果及生物膜特性.结果表明分层生物滴滤池出水水质能够更快的达到稳定,出水水质波动范围较小,去除率更高,且生物膜活性也较高.说明组合式分层生物滴滤池较普通生物滴滤池有一定的优越性.

  4. Biogas purification using membrane micro-aeration: A mass transfer analysis

    Directory of Open Access Journals (Sweden)

    Wathsala Perera, Deshai Botheju, Rune Bakke

    2014-01-01

    Full Text Available When sulfur containing organic feedstocks undergo anaerobic digestion, sulfides are formed due to the biological activities of sulfur reducing bacteria. Presence of hydrogen sulfide (H2S negatively affects the usage of biogas and needs to be reduced to levels that depend on the intended biogas application. Conversion of sulfide to its oxidized forms can be carried out by aerobic chemolithotrophic bacteria consuming oxygen as the electron acceptor. Membrane micro-aeration is a recently developed reliable method of safely supplying oxygen into anaerobic digesters. In this study, mass transfer models are developed to represent diffusion and back diffusion of gases through tubular polydimethylsiloxane (PDMS membranes. The models are utilized to determine the required membrane area and length in order to supply the stoichiometric amount of oxygen for biologically oxidizing a given amount of sulfide feed into elemental sulfur. Penetration of oxygen and nitrogen into the digester and transfer of methane, carbon dioxide and hydrogen sulfide back into the membrane tube are analyzed using these mass transfer models. Circulating air or aerated water inside the membrane tube is considered as two alternatives for supplying micro-aeration to the digester. Literature digester performance and sulfide data are used for example calculations. The required membrane length depends on circulating water flow rates and dissolved oxygen concentrations when water is used inside the membrane. A considerable fraction of CO2 can also be removed from the biogas in this case. Circulating air inside the membrane is, however, more promising solution as it requires much less membrane area and thereby also causes insignificant methane loss. The proposed membrane micro-aeration technique cuts N2 biogas dilution in half compared to direct air purging for in-situ sulfide oxidation.

  5. Optimized aeration strategies for nitrogen and phosphorus removal with aerobic granular sludge.

    Science.gov (United States)

    Lochmatter, Samuel; Gonzalez-Gil, Graciela; Holliger, Christof

    2013-10-15

    Biological wastewater treatment by aerobic granular sludge biofilms offers the possibility to combine carbon (COD), nitrogen (N) and phosphorus (P) removal in a single reactor. Since denitrification can be affected by suboptimal dissolved oxygen concentrations (DO) and limited availability of COD, different aeration strategies and COD loads were tested to improve N- and P-removal in granular sludge systems. Aeration strategies promoting alternating nitrification and denitrification (AND) were studied to improve reactor efficiencies in comparison with more classical simultaneous nitrification-denitrification (SND) strategies. With nutrient loading rates of 1.6 gCOD L(-1) d(-1), 0.2 gN L(-1) d(-1), and 0.08 gP L(-1) d(-1), and SND aeration strategies, N-removal was limited to 62.3 ± 3.4%. Higher COD loads markedly improved N-removal showing that denitrification was limited by COD. AND strategies were more efficient than SND strategies. Alternating high and low DO phases during the aeration phase increased N-removal to 71.2 ± 5.6% with a COD loading rate of 1.6 gCOD L(-1) d(-1). Periods of low DO were presumably favorable to denitrifying P-removal saving COD necessary for heterotrophic N-removal. Intermittent aeration with anoxic periods without mixing between the aeration pulses was even more favorable to N-removal, resulting in 78.3 ± 2.9% N-removal with the lowest COD loading rate tested. P-removal was under all tested conditions between 88 and 98%, and was negatively correlated with the concentration of nitrite and nitrate in the effluent (r = -0.74, p < 0.01). With low COD loading rates, important emissions of undesired N2O gas were observed and a total of 7-9% of N left the reactor as N2O. However, N2O emissions significantly decreased with higher COD loads under AND conditions.

  6. Elimination of micropollutants and transformation products from a wastewater treatment plant effluent through pilot scale ozonation followed by various activated carbon and biological filters.

    Science.gov (United States)

    Knopp, Gregor; Prasse, Carsten; Ternes, Thomas A; Cornel, Peter

    2016-09-01

    Conventional wastewater treatment plants are ineffective in removing a broad range of micropollutants, resulting in the release of these compounds into the aquatic environment, including natural drinking water resources. Ozonation is a suitable treatment process for micropollutant removal, although, currently, little is known about the formation, behavior, and removal of transformation products (TP) formed during ozonation. We investigated the elimination of 30 selected micropollutants (pharmaceuticals, X-ray contrast media, industrial chemicals, and TP) by biological treatment coupled with ozonation and, subsequently, in parallel with two biological filters (BF) or granular activated carbon (GAC) filters. The selected micropollutants were removed to very different extents during the conventional biological wastewater treatment process. Ozonation (specific ozone consumption: 0.87 ± 0.29 gO3 gDOC(-1), hydraulic retention time: 17 ± 3 min) eliminated a large number of the investigated micropollutants. Although 11 micropollutants could still be detected after ozonation, most of these were eliminated in subsequent GAC filtration at bed volumes (BV) of approximately 25,000 m(3) m(-3). In contrast, no additional removal of micropollutants was achieved in the BF. Ozonation of the analgesic tramadol led to the formation of tramadol-N-oxide that is effectively eliminated by GAC filters, but not by BF. For the antiviral drug acyclovir, the formation of carboxy-acyclovir was observed during activated sludge treatment, with an average concentration of 3.4 ± 1.4 μg L(-1) detected in effluent samples. Subsequent ozonation resulted in the complete elimination of carboxy-acyclovir and led to the formation of N-(4-carbamoyl-2-imino-5-oxo imidazolidin)-formamido-N-methoxyacetetic acid (COFA; average concentration: 2.6 ± 1.0 μg L(-1)). Neither the BF nor the GAC filters were able to remove COFA. These results highlight the importance of considering TP in the

  7. Performance of digester decant system with biological filter followed by constructed wetland and solar reactor in the treatment of domestic sewage

    Directory of Open Access Journals (Sweden)

    Delfran Batista dos Santos

    2012-08-01

    Full Text Available This study aimed to analyze the performance of digester decant system with biological filter followed by constructed wetland and solar reactor in the treatment of domestic sewage from Milagres rural community in Apodi-RN. The treatment system was monitored for the period of October and November 2010, 48 days after planting Pennisetum purpureum Schumach. Samples of domestic sewage were collected at different stages of treatment, in four replications on time, to determine physicochemical and microbiological characteristics about the system performance. The results indicated significant removal of turbidity, biochemical oxygen demand, chemical oxygen demand, total solids, suspended solids, phosphorus and oil and grease using the set digester decant with biological filter, followed by constructed wetland and solar reactor; the association of average solar radiation of 28.73 MJ m-2 d-1, effluent depth of 0.10 m on reactor and time of sun exposure of 12 hours provided removal of fecal coliform up to 99.99% of domestic sewage in Apodi, RN, the treated effluent met microbiological standard of the Brazilian guidelines for agricultural use with restrictions.

  8. Evaluation of the metabolic diversity of microbial communities in four different filter layers of a constructed wetland with vertical flow by Biolog analysis.

    Science.gov (United States)

    Salomo, S; Münch, C; Röske, I

    2009-10-01

    The community-level substrate utilization test based on direct incubation of environmental samples in Biolog EcoPlates is a suitable and sensitive tool to characterize microbial communities. The aim of this study was to investigate the influence of plant roots and soil structure on the metabolic diversity of microorganisms in a constructed wetland with vertical flow. Sediment samples were taken from different filter depths representing specific filter layers. The color development representing the substrate utilization was measured with the samples over a period of 10 days. The average well color development (AWCD) for all carbon sources was calculated as an indicator of total activity and in order to compensate the influence of the inoculum's density on the color development in the plates. After transformation by dividing by the AWCD, the optical density data were analysed by principal component analysis (PCA). An analysis of the kinetic profile of the AWCD was carried out to increase the analytical power of the method. The corrected data have been successfully fit to the logistic growth equation. Three kinetic model parameters, the asymptote (K), the exponential rate of color change (p) and the time to the midpoint of the exponential portion of the curve (s), were used for statistical analysis of the physiological profile of the microbial community in the different filter layers of the constructed wetland. We found out that in the upper two horizons, which were rooted most densely, mainly easily degradable materials like specific carbohydrates were utilized, while in the lower layers, where only single roots occur, more biochemically inert compounds, e.g. 2-hydroxy benzoic acid, were utilized. Furthermore it could be shown that microorganisms in the surface layer benefited from the plant litter because they can utilize decay products of these. In the lower filter layers specialists took advantage because they had to cope with the biochemically inert materials and

  9. Effect of aeration rate on composting of penicillin mycelial dreg.

    Science.gov (United States)

    Chen, Zhiqiang; Zhang, Shihua; Wen, Qinxue; Zheng, Jun

    2015-11-01

    Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90L/(min·kg) organic matter (OM) were examined. The principal physicochemical parameters were monitored during the 32day composting period. Results showed that the higher aeration rate of 0.90L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation; but the lower aeration rate of 0.15L/(min·kg) did induce an accumulation of NH4(+)-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures≥55°C, the maximum NO3(-)-N content and seed germination, and the minimum C/N ratio were obtained with 0.50L/(min·kg) OM. Therefore, aeration rates of 0.50L/(min·kg) OM can be recommended for composting penicillin mycelial dreg.

  10. Interaction between afternoon aeration and tilapia stocking density

    Directory of Open Access Journals (Sweden)

    Francisco Roberto dos Santos Lima

    2016-01-01

    Full Text Available The present study aimed at determining the effects of the interaction between afternoon aeration and stocking density of Nile tilapia on variables of water and soil quality, growth performance and effluent quality. The experiment was a 3 x 2 factorial randomized block design, with three stocking densities (8, 12 and 16 fish per tank or 43.5, 65.3, and 87.0 g m-3 under two mechanical aeration regimes, absence (control; three replicates and afternoon aeration (four replicates. The afternoon aeration was carried out from 12.00 a.m. up to 18.00 p.m. from the 3rd week until the end of the experiment. Except for the 16-fish tanks, the lowest concentrations of total ammonia nitrogen were found in the tanks with higher density of fish provided with afternoon aeration. Nitrite concentrations were lower in the 8-fish aerated tanks. In intensive system, the afternoon aeration of the fish culture water is an efficient management of water quality to remove gaseous ammonia and nitrite from water, but it is not appropriate to remove hydrogen sulfide from water.

  11. Research on Aeration Systems Efficiency in Small Wastewater Treatment Plants

    OpenAIRE

    Ala Sokolova

    2011-01-01

    Large amount of small wastewater treatment plants does not work properly. One of the reasons could be wrong design of the aeration system. Therefore, the aim of this research is to analyse the performance of two aeration systems used in Lithuanian small wastewater treatment plants. Both aeration systems are designed for the following parameters: 4 PE and 0,8 m3/d wastewater flow. These data correspond to the oxygen requirement of 40,9 g O2/h. Summarizing the results of the research, it was fo...

  12. Optical high-resolution analysis of rotational movement: testing circular spatial filter velocimetry (CSFV) with rotating biological cells

    Science.gov (United States)

    Schaeper, M.; Schmidt, R.; Kostbade, R.; Damaschke, N.; Gimsa, J.

    2016-07-01

    Circular spatial filtering velocimetry (CSFV) was tested during the microscopic registration of the individual rotations of baker’s yeast cells. Their frequency-dependent rotation (electrorotation; ER) was induced in rotating electric fields, which were generated in a glass chip chamber with four electrodes (600 μm tip-to-tip distance). The electrodes were driven with sinusoidal quadrature signals of 5 or 8 V PP with frequencies up to 3 MHz. The observed cell rotation was of the order of 1-100 s per revolution. At each measuring frequency, the independent rotations of up to 20 cells were simultaneously recorded with a high-speed camera. CSFV was software-implemented using circular spatial filters with harmonic gratings. ER was proportional to the phase shift between the values of the spatial filtering signal of consecutive frames. ER spectra obtained by CSFV from the rotation velocities at different ER-field frequencies agreed well with manual measurements and theoretical spectra. Oscillations in the rotation velocity of a single cell in the elliptically polarized field near an electrode, which were resolved by CSFV, could not be visually discerned. ER step responses after field-on were recorded at 2500 frames per second. Analysis proved the high temporal resolution of CSFV and revealed a largely linear torque-friction relation during the acceleration phase of ER. Future applications of CSFV will allow for the simple and cheap automated high-resolution analysis of rotational movements where mechanical detection has too low a resolution or is not possible, e.g. in polluted environments or for gas and fluid vortices, microscopic objects, etc.

  13. Competitive Study of Common Aeration System Application in Urban Water Supply Project%常用曝气系统在城市给水工程中的应用对比

    Institute of Scientific and Technical Information of China (English)

    何树龙

    2011-01-01

    生物接触氧化法作为城市给水工程生物预处理工艺,近年来得到了日益广泛的实际应用。本文对给水生物接触氧化法预处理工艺中常用的两种曝气系统(微孔曝气器曝气和穿孔管曝气)作了简单介绍,并结合中试试验和工程实践对这两种不同曝气系统作了充氧性能、系统造价、运行成本及运行管理等方面的比较分析。研究表明,在实际污水处理厂生物池曝气系统应用中,采用微孔曝气器的曝气系统优于采用穿孔管的曝气系统。%As biological pretreatment process of urban water supply project,biological contact oxidation has been applied widely in practical application.This paper briefly introduces two kinds of aeration systems(Microporous Aerator Aeration System and Perforated Pipe Aeration System) usually adopted in pretreatment process of water supply biological contact oxidation.The comparative analysis of oxygenation capacity,system cost,operation cost and operation management of these two kinds of aeration systems were conducted in connection with pilot test and project practice.Researches show that Microporous Aerator Aeration System outperforms Perforated Pipe Aeration System in sewage treatment plant aeration system application.

  14. Micro-aeration for hydrogen sulfide removal from biogas

    Science.gov (United States)

    Duangmanee, Thanapong

    The presence of sulfur compounds (e.g. protein, sulfate, thiosulfate, sulfite, etc.) in the feed stream generates highly corrosive and odorous hydrogen sulfide during anaerobic digestion. The high sulfide level in the biogas stream is not only poisonous to many novel metal catalysts employed in thermo-catalytic processes but also reduces the quality of methane to produce renewable energy. This study used an innovative, low-maintenance, low-cost biological sulfide removal technology to remove sulfides simultaneously from both gas and liquid phase. ORP (Oxidation-Reduction-Potential) was used as the controlling parameter to precisely regulate air injection to the sulfide oxidizing unit (SOU). The microaeration technique provided just enough oxygen to partially oxidize sulfides to elemental sulfur without inhibiting methanogenesis. The SOU was equipped with a diffuser at the bottom for the dispersion of sulfide-laden biogas and injected air throughout the column. The SOU can be operated as a standalone unit or coupled with an anaerobic digester to simultaneously remove sulfide from the biogas and effluent. The integrated system was capable of reducing hydrogen sulfide in biogas from 2,450 to less than 2 ppmV with minimal sulfate production at the highest available sulfide loading rate of 0.24 kg/m3-day. More than 98% of sulfide removed was recovered as elemental sulfur. However, the standalone SOU was able to operate at high hydrogen sulfide loading of 1.46 kg/m 3-day at inlet sulfide concentration of 3000 ppmV and reduce the off-gas hydrogen sulfide concentrations to less than 10 ppmV. The experiment also revealed that the ORP controlled aeration was sensitive enough to prevent oxygen overdosing (dampening effect) during unexpected surges of aeration. Using generalized linear regression, a model predicting output H2S concentration based on input H2S concentrations, SOU medium heights, and biogas flow rates, was derived. With 95% confidence, output H2S concentration

  15. INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

    Science.gov (United States)

    Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

  16. Comparison of Energy Dissipation with and without Aerators

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Experimental results showed that aerators increase the energy dissipation of the flow in the channel by reducing the velocity coefficient φ in the deflector bucket and the jet-trajectory length, by increasing energy dissipation of the jet flow in the air and the diffusion length of the jet falling into the pool and by reducing the energy intensity of the jet falling into the pool. The energy dissipation prevents wash out downstream.When air is not entrained in the water flow, the aerators act as artificial irregularities in the channel. The energy dissipation due to the aerators in the channel without entrained air is greater than when air is entrained in the water flow.Correlations of the experimental data can be used to estimate the energy dissipation effect of the aerators on the outlet structure for the three test cases.

  17. Biological sample collector

    Science.gov (United States)

    Murphy, Gloria A.

    2010-09-07

    A biological sample collector is adapted to a collect several biological samples in a plurality of filter wells. A biological sample collector may comprise a manifold plate for mounting a filter plate thereon, the filter plate having a plurality of filter wells therein; a hollow slider for engaging and positioning a tube that slides therethrough; and a slide case within which the hollow slider travels to allow the tube to be aligned with a selected filter well of the plurality of filter wells, wherein when the tube is aligned with the selected filter well, the tube is pushed through the hollow slider and into the selected filter well to sealingly engage the selected filter well and to allow the tube to deposit a biological sample onto a filter in the bottom of the selected filter well. The biological sample collector may be portable.

  18. Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of heterogeneous Fenton oxidation and biological process.

    Science.gov (United States)

    Xu, Peng; Han, Hongjun; Zhuang, Haifeng; Hou, Baolin; Jia, Shengyong; Xu, Chunyan; Wang, Dexin

    2015-04-01

    Laboratorial scale experiments were conducted in order to investigate a novel system integrating heterogeneous Fenton oxidation (HFO) with anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) process on advanced treatment of biologically pretreated coal gasification wastewater (CGW). The results indicated that HFO with the prepared catalyst (FeOx/SBAC, sewage sludge based activated carbon (SBAC) which loaded Fe oxides) played a key role in eliminating COD and COLOR as well as in improving the biodegradability of raw wastewater. The surface reaction and hydroxyl radicals (OH) oxidation were the mechanisms for FeOx/SBAC catalytic reaction. Compared with ANMBBR-BAF process, the integrated system was more effective in abating COD, BOD5, total phenols (TPs), total nitrogen (TN) and COLOR and could shorten the retention time. Therefore, the integrated system was a promising technology for engineering applications.

  19. CAVITATION CONTROL BY AERATION AND ITS COMPRESSIBLE CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; SU Pei-lan

    2006-01-01

    This paper presents an experimental investigation and a theoretical analysis of cavitation control by aeration and its compressible characteristics at the flow velocity V=20m/s-50m/s. Pressure waveforms with and without aeration in cavitation region were measured. The variation of compression ratio with air concentration was described, and the relation between the least air concentration to prevent cavitation erosion and flow velocity proposed based on our experimental study. The experimental results show that aeration remarkably increases the pressure in cavitation region, and the corresponding pressure wave exhibits a compression wave/shock wave. The pressure increase in cavitation region of high-velocity flow with aeration is due to the fact that the compression waves/shock wave after the flow is aerated. The compression ratio increases with air concentration rising. The relation between flow velocity and least air concentration to prevent cavitation erosion follows a semi-cubical parabola. Also, the speed of sound and Mach number of high-velocity aerated flow were analyzed.

  20. Effect of aeration on fast gas pressure tests

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu-jia; JIANG Cheng-lin; LI Xiao-wei; TANG Jun; WANG Chen; YANG Fei-long; WANG Fa-kai; ZHANG Chao-jie; DENG Shu-hua

    2009-01-01

    Given the problem of the long time required for testing gas pressure, we propose a fast-test method in which we used a technique of fast borehole sealing and air replenishing. Based on the characteristics of gas emission from boreholes to be tested, we built a theoretical model for calculating parameters during the process of increasing natural pressure and aeration. Using this model, we investigated the effect of different aeration conditions on velocity of pressure tests. The result shows that: 1) aerating air into boreholes can speed up gas pressure tests and 2) the more similar the pressure of the aerated air to the original gas pressure, the smaller the gas volume absorbed by coal and the shorter the time needed in pressure test. A case study in the Lu'an mining area shows that the time needed for gas pressure test is only 4 h using our method of aeration and 29 h under conditions of increasing natural pressure, saving time by 86.2%. This case study also indicates that, by using the aeration method, only one hour is needed for gas pressure to reach a stable state, which breaks the record of the shortest time needed for gas pressure tests in China.

  1. SAW synthesis with IDTs array and the inverse filter: toward a versatile SAW toolbox for microfluidics and biological applications

    CERN Document Server

    Riaud, Antoine; Thomas, Jean-Louis; Matar, Olivier Bou

    2016-01-01

    Surface acoustic waves (SAWs) are versatile tools to manipulate fluids at small scales for microfluidics and bio- logical applications. A non-exhaustive list of operations that can be performed with SAW includes sessile droplet displacement, atomization, division and merging but also the actuation of fluids embedded in microchannels or the manipulation of suspended particles. However, each of these operations requires a specific design of the wave generation system, the so-called interdigitated transducers (IDTs). Depending on the application, it might indeed be necessary to generate focused or plane, propagating or standing, aligned or shifted waves. Furthermore, the possibilities offered by more complex wave-fields such as acoustical vortices for particle tweezing and liquid twisting cannot be explored with classical IDTs. In this paper, we show that the inverse filter technique coupled with an interdigitated transducers array (IDTA) enables to synthesize all classical wave-fields used in microfluidics and ...

  2. A new step aeration approach towards the improvement of nitrogen removal in a full scale Carrousel oxidation ditch.

    Science.gov (United States)

    Jin, Pengkang; Wang, Xianbao; Wang, Xiaochang; Ngo, Huu Hao; Jin, Xin

    2015-12-01

    Two aeration modes, step aeration and point aeration, were used in a full-scale Carrousel oxidation ditch with microporous aeration. The nitrogen removal performance and mechanism were analyzed. With the same total aeration input, both aeration modes demonstrated good nitrification outcomes with the average efficiency in removing NH4(+)-N of more than 98%. However, the average removal efficiencies for total nitrogen were 89.3% and 77.6% under step aeration and point aeration, respectively. The results indicated that an extended aerobic zone followed the aeration zones could affect the proportion of anoxic and oxic zones. The step aeration with larger anoxic zones indicated better TN removal efficiency. More importantly, step aeration provided the suitable environment for both nitrifiers and denitrifiers. The diversity and relative abundance of denitrifying bacteria under the step aeration (1.55%) was higher than that under the point aeration (1.12%), which resulted in an overall higher TN removal efficiency.

  3. [Research of controlling condition for aeration stabilization pond dealing with sanitary waste of countryside].

    Science.gov (United States)

    Li, Huai-Zheng; Yao, Shu-Jun; Xu, Zu-Xin; Chen, Wei-Bing

    2012-10-01

    According to research of some problems, such as the hydraulic detention time that aeration stabilization pond deals with sanitary waste of countryside, dissolved oxygen in pond during the process of aeration, the concentration distribution of sludge and different aeration periods affecting on the treatment efficiency, we can acquire good treatment efficiency and energy consumption of economy. The results indicate that under the aeration stabilization pond of this experiment, 4 d is the best hydraulic detention time with this aeration stabilization pond. Time of the discontinuous running aeration should be greater than 15 min. The concentration distribution of sludge can reach equilibrium at each point of aeration stabilization pond between 2 min and 10 min. The best aeration period of dislodging the pollutant is 0.5 h aeration/1.0 h cut-off.

  4. Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.

    Science.gov (United States)

    Lu, Xiao-Ming; Lu, Peng-Zhen; Huang, Min-Sheng; Dai, Ling-Peng

    2013-01-01

    Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water.

  5. Improving signal to noise in labeled biological specimens using energy-filtered TEM of sections with a drift correction strategy and a direct detection device.

    Science.gov (United States)

    Ramachandra, Ranjan; Bouwer, James C; Mackey, Mason R; Bushong, Eric; Peltier, Steven T; Xuong, Nguyen-Huu; Ellisman, Mark H

    2014-06-01

    Energy filtered transmission electron microscopy techniques are regularly used to build elemental maps of spatially distributed nanoparticles in materials and biological specimens. When working with thick biological sections, electron energy loss spectroscopy techniques involving core-loss electrons often require exposures exceeding several minutes to provide sufficient signal to noise. Image quality with these long exposures is often compromised by specimen drift, which results in blurring and reduced resolution. To mitigate drift artifacts, a series of short exposure images can be acquired, aligned, and merged to form a single image. For samples where the target elements have extremely low signal yields, the use of charge coupled device (CCD)-based detectors for this purpose can be problematic. At short acquisition times, the images produced by CCDs can be noisy and may contain fixed pattern artifacts that impact subsequent correlative alignment. Here we report on the use of direct electron detection devices (DDD's) to increase the signal to noise as compared with CCD's. A 3× improvement in signal is reported with a DDD versus a comparably formatted CCD, with equivalent dose on each detector. With the fast rolling-readout design of the DDD, the duty cycle provides a major benefit, as there is no dead time between successive frames.

  6. A Guide for Developing Standard Operating Job Procedures for the Activated Sludge - Aeration & Sedimentation Process Wastewater Treatment Facility. SOJP No. 5.

    Science.gov (United States)

    Mason, George J.

    This guide for developing standard operating job procedures for wastewater treatment facilities is devoted to the activated sludge aeration and sedimentation process. This process is for conversion of nonsettleable and nonfloatable materials in wastewater to settleable, floculated biological groups and separation of the settleable solids from the…

  7. Comparison between lab- and full-scale applications of in situ aeration of an old landfill and assessment of long-term emission development after completion.

    Science.gov (United States)

    Hrad, Marlies; Gamperling, Oliver; Huber-Humer, Marion

    2013-10-01

    Sustainable landfilling has become a fundamental objective in many modern waste management concepts. In this context, the in situ aeration of landfills has been recognised for its potential to convert conventional anaerobic landfills into biological stabilised state, whereby both current and potential (long-term) emissions of the landfilled waste are mitigated. In recent years, different in situ aeration concepts have been successfully applied in Europe, North America and Asia, all pursuing different objectives and strategies. In Austria, the first full-scale application of in situ landfill aeration by means of low pressure air injection and simultaneous off-gas collection and treatment was implemented on an old, small municipal solid waste (MSW) landfill (2.6ha) in autumn 2007. Complementary laboratory investigations were conducted with waste samples taken from the landfill site in order to provide more information on the transferability of the results from lab- to full-scale aeration measures. In addition, long-term emission development of the stabilised waste after aeration completion was assessed in an ongoing laboratory experiment. Although the initial waste material was described as mostly stable in terms of the biological parameters gas generation potential over 21days (GP21) and respiration activity over 4days (RA4), the lab-scale experiments indicated that aeration, which led to a significant improvement of leachate quality, was accompanied by further measurable changes in the solid waste material under optimised conditions. Even 75weeks after aeration completion the leachate, as well as gaseous emissions from the stabilised waste material, remained low and stayed below the authorised Austrian discharge limits. However, the application of in situ aeration at the investigated landfill is a factor 10 behind the lab-based predictions after 3years of operation, mainly due to technical limitations in the full-scale operation (e.g. high air flow resistivity due

  8. Numerical simulation of landfill aeration using computational fluid dynamics.

    Science.gov (United States)

    Fytanidis, Dimitrios K; Voudrias, Evangelos A

    2014-04-01

    The present study is an application of Computational Fluid Dynamics (CFD) to the numerical simulation of landfill aeration systems. Specifically, the CFD algorithms provided by the commercial solver ANSYS Fluent 14.0, combined with an in-house source code developed to modify the main solver, were used. The unsaturated multiphase flow of air and liquid phases and the biochemical processes for aerobic biodegradation of the organic fraction of municipal solid waste were simulated taking into consideration their temporal and spatial evolution, as well as complex effects, such as oxygen mass transfer across phases, unsaturated flow effects (capillary suction and unsaturated hydraulic conductivity), temperature variations due to biochemical processes and environmental correction factors for the applied kinetics (Monod and 1st order kinetics). The developed model results were compared with literature experimental data. Also, pilot scale simulations and sensitivity analysis were implemented. Moreover, simulation results of a hypothetical single aeration well were shown, while its zone of influence was estimated using both the pressure and oxygen distribution. Finally, a case study was simulated for a hypothetical landfill aeration system. Both a static (steadily positive or negative relative pressure with time) and a hybrid (following a square wave pattern of positive and negative values of relative pressure with time) scenarios for the aeration wells were examined. The results showed that the present model is capable of simulating landfill aeration and the obtained results were in good agreement with corresponding previous experimental and numerical investigations.

  9. Pure and aerated water entry of a flat plate

    Science.gov (United States)

    Ma, Z. H.; Causon, D. M.; Qian, L.; Mingham, C. G.; Mai, T.; Greaves, D.; Raby, A.

    2016-01-01

    This paper presents an experimental and numerical investigation of the entry of a rigid square flat plate into pure and aerated water. Attention is focused on the measurement and calculation of the slamming loads on the plate. The experimental study was carried out in the ocean basin at Plymouth University's COAST laboratory. The present numerical approach extends a two-dimensional hydro-code to compute three-dimensional hydrodynamic impact problems. The impact loads on the structure computed by the numerical model compare well with laboratory measurements. It is revealed that the impact loading consists of distinctive features including (1) shock loading with a high pressure peak, (2) fluid expansion loading associated with very low sub-atmospheric pressure close to the saturated vapour pressure, and (3) less severe secondary reloading with super-atmospheric pressure. It is also disclosed that aeration introduced into water can effectively reduce local pressures and total forces on the flat plate. The peak impact loading on the plate can be reduced by half or even more with 1.6% aeration in water. At the same time, the lifespan of shock loading is prolonged by aeration, and the variation of impulse is less sensitive to the change of aeration than the peak loading.

  10. Methanogenesis acceleration of fresh landfilled waste by micro-aeration

    Institute of Scientific and Technical Information of China (English)

    SHAO Li-ming; HE Pin-jing; ZHANG Hua; YU Xiao-hua; LI Guo-jian

    2005-01-01

    When municipal solid waste(MSW) with high content of food waste is landfilled, the rapid hydrolysis of food waste results in the imbalance of anaerobic metabolism in the landfill layer, indicated by accumulation of volatile fatty acids(VFA) and decrease of pH value.This occurrence could lead to long lag time before the initiation of methanogenesis and to the production of strong leachate. Simulated landfill columns with forced aeration, with natural ventilation, and with no aeration, were monitored regarding their organics degradation rate with leachate recirculation. Hydrolysis reactions produced strong leachate in the column with no aeration. With forced aeration, the produced VFA could be effectively degraded, leading to the reduction in COD of the leachate effluent since the week 3. The CH4 in the frequency of twice/d, could amount to 40% (v/v) after only 20 weeks. This amount had increased up to 50% afterward even with no aeration. Most of COD in the recirculated leachate was removed. Using natural ventilation, CH4 could also be produced and the COD of the leachate effluent be reduced after 10 weeks of operation. However, the persistent existence of oxygen in the landfill layer yielded instability in methanogenesis process.

  11. 双层填料中置生物活性炭滤池中试优化研究%THE PILOT STUDY ON THE OPTIMIZATION OF MID-SET BIOLOGICAL ACTIVATED CARBON FILTER WITH TWO-STAGE FILTER

    Institute of Scientific and Technical Information of China (English)

    李少文; 杨永飞; 陆少鸣

    2012-01-01

    The mid-set biological activated carbon filter with double filler loading was used to remove the turbidity and organic matter from water whose turbidity was about 1 NTU effluent from sedimentation tank. The results were as following. Filling the thickness of 3 m cylindrical carbon whose diameter was φ3 mm, the cushion thickness of 0.7 m was filled with diameter φ3 ~ 5 mm and thickness of 1.2 m with diameter φ6 ~ 8 mm lightweight ceramic. The experiment was operated at 12 m · h-1 filter speed while the gas-water volume ratio was 0.2:1, the average pressure loss were 3.41 kPa and 2.81 kPa, CODMn average removal rates were 41.5% and 46.3%; the latter was operated at the 16 m·h-1 filtration rate while the gas-water volume ratio was 0.2:1, the average pressure loss was 4.08 kPa, CODMn, average removal rate was 41.4%.%采用中置生物活性炭滤池,装填双层填料,对进水浊度约1 NTU左右的沉淀池出水进行去除浊度和有机物中试.结果表明,装填厚3m粒径φ3 mm柱状炭、垫层分别采用厚0.7m粒径φ3~5 mm与厚1.2m粒径φ6~8 mm轻质陶粒,于12 m·h-1滤速、气水体积比为0.2∶1的工况下运行时,平均水压损失分别为3.41 kPa和2.81 kPa,CODMn平均去除率分别为41.5%和46.3%;后者在16m.h-1滤速,气水体积比0.2∶1的工况下运行时,平均水压损失为4.08kPa,CODMn平均去除率为41.4%.

  12. Energy Consumption and Energy Potential of Miraco Bubble Aerated Oxidation Ditch & BAF and Measures of Energy Saving%微曝氧化沟+BAF污水深度处理能耗潜能分析与节能研究

    Institute of Scientific and Technical Information of China (English)

    时章明; 沈浩; 姜信杰; 陈通; 余煌

    2012-01-01

    The advanced treatment of urban sewage and the related energy consumption are issues for concern. The wastewater treatment process of miraco bubble-aerated oxidation ditch and biological aerated filter is studied in this paper, its energy consumption and the process energy potential are analyzed from the perspective of the technical process. The results show that the maximum power consumption in the process of miraco bubble-aerated oxidation ditch accounts for 54.59% in the total power consumption, followed by those in water pumping stations, sludge pumping stations and water pumping stations, respectively, which account for 13.49%, 9.56% and 8.69% in the total power consumption. The aeration system and the sewage sludge dynamic system take still the most important part in the energy consumption. The reductions of chemical energy potential and biological energy potential in the entire process are 231.6 × l06hj/d and 201.5 xl06kJ/d. The potential energy in the sewage water is higher than the total energy consumption, the rates of the increase in the energy consumption and decrease in the energy potential are the greatest in the miraco bubble-aerated oxidation ditch. Some energy-saving measures are proposed for the process, the electrical equipment and the re-use of resources.%城市污水的深度处理必然成为未来发展的趋势,污水处理的能耗问题已经引起人们的关注.某城市污水处理厂采用的是微曝氧化沟+生物曝气滤池(BAF)的污水深度处理工艺,从该工艺处理流程的角度进行了能耗与工序潜能分析,将能耗与潜能联系起来进行了研究.结果表明,工序中微曝氧化沟耗电量最大,占污水处理工艺总电耗的54.59%,其次是进水泵房、污泥泵房和出水泵房,分别占总电耗的13.49%,9.56%和8.69%,曝气系统和污水污泥的动力系统仍是耗能的重点;整个处理工序中化学与生化潜能的减少量分别为231.6×106kJ/d与201.5×106kJ/d,污水进

  13. Comments on the paper 'A novel 3D wavelet-based filter forvisualizing features in noisy biological data', by Moss et al.

    Energy Technology Data Exchange (ETDEWEB)

    Luengo Hendriks, Cris L.; Knowles, David W.

    2006-02-04

    Moss et al.(2005) describe, in a recent paper, a filter thatthey use to detect lines. We noticed that the wavelet on which thisfilter is based is a difference of uniform filters. This filter is anapproximation to the second derivative operator, which is commonlyimplemented as the Laplace of Gaussian (or Marr-Hildreth) operator (Marr&Hildreth, 1980; Jahne, 2002), Figure 1. We have compared Moss'filter with 1) the Laplace of Gaussian operator, 2) an approximation ofthe Laplace of Gaussian using uniform filters, and 3) a few common noisereduction filters. The Laplace-like operators detect lines by suppressingimage features both larger and smaller than the filter size. The noisereduction filters only suppress image features smaller than the filtersize. By estimating the signal to noise ratio (SNR) and mean squaredifference (MSD) of the filtered results, we found that the filterproposed by Moss et al. does not outperform the Laplace of Gaussianoperator. We also found that for images with extreme noise content, linedetection filters perform better than the noise reduction filters whentrying to enhance line structures. In less extreme cases of noise, thestandard noise reduction filters perform significantly better than boththe Laplace of Gaussian and Moss' filter.

  14. Emissions of ammonia, carbon dioxide, and hydrogen sulfide from swine wastewater during and after acidification treatment: effect of pH, mixing and aeration

    DEFF Research Database (Denmark)

    Dai, Xiao-Rong; Blanes-Vidal, Victoria

    2013-01-01

    This study aimed at evaluating the effect of swine slurry acidification and acidification-aeration treatments on ammonia (NH(3)), carbon dioxide (CO(2)) and hydrogen sulfide (H(2)S) emissions during slurry treatment and subsequent undisturbed storage. The study was conducted in an experimental...... setup consisting of nine dynamic flux chambers. Three pH levels (pH = 6.0, pH = 5.8 and pH = 5.5), combined with short-term aeration and venting (with an inert gas) treatments were studied. Acidification reduced average NH(3) emissions from swine slurry stored after acidification treatment compared...... on average NH(3), CO(2) and H(2)S emissions both during the process and from stored slurry after venting treatments. During aeration treatment, the NH(3), CO(2) and H(2)S release pattern observed was related to the liquid turbulence caused by the gas bubbles rather than to biological oxidation processes...

  15. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

    In this paper we explore the boundary between biology and the study of formal systems (logic). In the end, we arrive at a summary formalism, a chapter in "boundary mathematics" where there are not only containers but also extainers ><, entities open to interaction and distinguishing the space that they are not. The boundary algebra of containers and extainers is to biologic what boolean algebra is to classical logic. We show how this formalism encompasses significant parts of the logic of DNA replication, the Dirac formalism for quantum mechanics, formalisms for protein folding and the basic structure of the Temperley Lieb algebra at the foundations of topological invariants of knots and links.

  16. Experimental Analysis of Pressure Fluctuations behind a Bottom Aerator

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Experimental observations show that the random process of two-phase flow beh ind an aerator is an ergodic process and its amplitude distribution is similar t o a normal distribution. The maximum pressure fluctuation is at the re-attachme n t point where the jet-trajectory flow over the aerator re-attaches to bottom o f the channel, and its amplitude is 2-3 times larger than when there is no aerato r. There is a dominant frequency of 1.24 Hz in the model, but the coherence in th e frequency domain is not obvious for other frequencies beside the dominant frequ ency. There is a large vortex at the re-attachment point behind the aerator but correlation among the measurement points is not obvious in the time domain.

  17. RE-AERATION LAW OF WATER FLOW OVER SPILLWAYS

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiang-ju; LUO Lin; CHEN Yong-can; ZHAO Wen-qian

    2006-01-01

    In order to explore the re-aeration law of water flow over spillway, the transfer process of oxygen in water flow over spillway was studied. The interfacial mass transfer coefficients were obtained by experiments. The flow fields and the turbulence characteristics are simulated by numerical methods. The fractional volume of fluid model (VOF) of the air-water two phase flows was introduced to track the interface. Consequently, the quantitative expression of the interfacial mass transfer coefficients related with velocity and kinetic energy at the free surface was derived and the re-aeration model for the water flow over spillway was established. The examination with the experimental data of different conditions shows the validity of the re-aeration model for the water flow over spillways. This study will be important to evaluate the dissolved oxygen concentration and self-purification ability of rivers.

  18. Aerobic N2O emission for activated sludge acclimated under different aeration rates in the multiple anoxic and aerobic process.

    Science.gov (United States)

    Wang, Huoqing; Guan, Yuntao; Pan, Min; Wu, Guangxue

    2016-05-01

    Nitrous oxide (N2O) is a potent greenhouse gas that can be emitted during biological nitrogen removal. N2O emission was examined in a multiple anoxic and aerobic process at the aeration rates of 600mL/min sequencing batch reactor (SBRL) and 1200mL/min (SBRH). The nitrogen removal percentage was 89% in SBRL and 71% in SBRH, respectively. N2O emission mainly occurred during the aerobic phase, and the N2O emission factor was 10.1% in SBRL and 2.3% in SBRH, respectively. In all batch experiments, the N2O emission potential was high in SBRL compared with SBRH. In SBRL, with increasing aeration rates, the N2O emission factor decreased during nitrification, while it increased during denitrification and simultaneous nitrification and denitrification (SND). By contrast, in SBRH the N2O emission factor during nitrification, denitrification and SND was relatively low and changed little with increasing aeration rates. The microbial competition affected the N2O emission during biological nitrogen removal.

  19. AERATION EFFECT OF SUBMERGED JET ON HYDRAULIC CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A water-air two-phase turbulence mathematical model was proposed, The mass-weighted average was adoptedfor velocity, air mass fraction and turbulent parameters. Thealgebraic stress equation was used to calculate the Reynoldsstress. The pulsating flux of air mass fraction was simulatedby employing the concept of the eddy viscosity. The numericalsimulation of aerated flow in plunge pool shows that, for the same depth, aeration may decrease the time-averaged pressureon pool floor and increase slightly the turbulent intensity. Thecomputed concentration and pressure distributions coincidewith the experimental data.

  20. Fault detection and isolation of sensors in aeration control systems.

    Science.gov (United States)

    Carlsson, Bengt; Zambrano, Jesús

    2016-01-01

    In this paper, we consider the problem of fault detection (FD) and isolation in the aeration system of an activated sludge process. For this study, the dissolved oxygen in each aerated zone is assumed to be controlled automatically. As the basis for an FD method we use the ratio of air flow rates into different zones. The method is evaluated in two scenarios: using the Benchmark Simulation Model no. 1 (BSM1) by Monte Carlo simulations and using data from a wastewater treatment plant. The FD method shows good results for a correct and early FD and isolation.

  1. INVESTIGATION ON THE SPLASH LENGTH OF THE AERATED JET

    Institute of Scientific and Technical Information of China (English)

    Liu Shi-he; Qu Bo

    2003-01-01

    Atomized flow forms as an aerated jet from high dams impacts against the downstream water surface at high speed. Of all the regions of atomized flow the splash region is in the center of storm rainfall, which might cause certain damage to the hydropower stations and thence more attention should be paid. In this paper the impact of the water drop at the outer edge of the aerated jet against the downstream water surface was analyzed, and the motion of the splash water drop was investigated. Furthermore, a new formula for the calculation of the splash length was suggested, which is in good agreement with the data of model tests and prototype observation.

  2. Selection of optimum conditions of medium acidity and aeration for submerget cultivation of Bacillus thuringiensis and Beauveria bassiana

    Directory of Open Access Journals (Sweden)

    O. A. Dregval

    2010-06-01

    Full Text Available The paper deals with the influence of medium pH and aeration rate on growth and sporulation of Bacillus thuringiensis and Вeauveria bassiana, which are main constituents of the complex microbial insecticide. It was established optimal medium pH for B. thuringiensis – 6.0 and for В. bassiana – 6.0–7.0. The maximum productivity of the studied microorganisms was observed in the same range of aeration – 7– 14 mmol O2/l/h. The selected conditions of cultivation are necessary for the production of complex biological insecticide based on the association of B. thuringiensis and B. bassiana.

  3. Comments on the paper "A novel 3D wavelet-based filter for visualizing features in noisy biological data", by Moss et al.

    OpenAIRE

    Luengo Hendriks, Cris. L.; David W Knowles

    2006-01-01

    Moss et al.(2005) describe, in a recent paper, a filter that they use to detect lines. We noticed that the wavelet on which this filter is based is a difference of uniform filters. This filter is an approximation to the second derivative operator, which is commonly implemented as the Laplace of Gaussian (or Marr-Hildreth) operator (Marr & Hildreth, 1980; Jahne, 2002), Figure 1. We have compared Moss' filter with 1) the Laplace of Gaussian operator, 2) an approximation of the Laplace of G...

  4. 7 CFR 201.55a - Moisture and aeration of substratum.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Moisture and aeration of substratum. 201.55a Section... and aeration of substratum. (a) The substratum must be moist enough to supply the needed moisture to the seeds at all times. Excessive moisture which will restrict aeration of the seeds should be...

  5. Intermittent aeration to improve wastewater treatment efficiency in pilot-scale constructed wetland.

    Science.gov (United States)

    Uggetti, Enrica; Hughes-Riley, Theodore; Morris, Robert H; Newton, Michael I; Trabi, Christophe L; Hawes, Patrick; Puigagut, Jaume; García, Joan

    2016-07-15

    Forced aeration of horizontal subsurface flow constructed wetlands (HSSF CWs) is nowadays a recognized method to improve treatment efficiency, mainly in terms of ammonium removal. While numerous investigations have been reported testing constant aeration, scarce information can be found about the efficiency of intermittent aeration. This study aims at comparing continuous and intermittent aeration, establishing if there is an optimal regime that will increase treatment efficiency of HSSF CWs whilst minimizing the energy requirement. Full and intermittent aeration were tested in a pilot plant of three HSSF CWs (2.64m(2) each) fed with primary treated wastewater. One unit was fully aerated; one intermittently aerated (i.e. by setting a limit of 0.5mg/L dissolved oxygen within the bed) with the remaining unit not aerated as a control. Results indicated that intermittent aeration was the most successful operating method. Indeed, the coexistence of aerobic and anoxic conditions promoted by the intermittent aeration resulted in the highest COD (66%), ammonium (99%) and total nitrogen (79%) removals. On the other hand, continuous aeration promotes ammonium removal (99%), but resulted in nitrate concentrations in the effluent of up to 27mg/L. This study demonstrates the high potential of the intermittent aeration to increase wastewater treatment efficiency of CWs providing an extreme benefit in terms of the energy consumption.

  6. Effect of cyclic aeration on fouling in submerged membrane bioreactor for wastewater treatment.

    Science.gov (United States)

    Wu, Jun; He, Chengda

    2012-07-01

    Due to the inefficiency of aeration measures in preventing fouling by soluble and colloidal particles. The effect of alternating high/low cyclic aeration mode on the membrane fouling in the submerged membrane bioreactor was studied by comparing to fouling in a constant aeration mode. Results indicated a higher overall fouling rate in the cyclic aeration mode than in the constant aeration. However, a higher percentage of reversible fouling was observed for the cyclic aeration mode. The membrane permeability can be more easily recovered from physical cleaning such as backwashing in the cyclic aeration mode. The activated sludge floc size distribution analysis revealed a floc destruction and re-flocculation processes caused by the alternating high/low aeration. The short high aeration period could prevent the destruction of strong strength bonds within activated sludge flocs. Therefore, less soluble and colloidal material was observed in the supernatant due to the preservation of the strong strength bonds. The weak strength bonds damaged in the high aeration period could be recovered in the re-flocculation process in the low aeration period. The floc destruction and re-flocculation processes were suggested to be the main reason for the low irreversible fouling in the cyclic aeration mode.

  7. Nutrients removal using moving beds with aeration cycles

    Energy Technology Data Exchange (ETDEWEB)

    Martin Martin, A.; Foresti, E.; Garcia-Encina, P. A.

    2009-07-01

    Moving Bed Biofilm Reactors (MBBR) are based on the biomass growth over a media that moves into the reactor due to aeration, mechanical agitation or recirculation. These reactors have been gaining popularity and they are employed in hundreds of plants everywhere with different treatment purposes (organic matter removal, nitrification/denitrification), both for urban and industrial wastewater. (Author)

  8. Aeration of bread dough influenced by different way processing

    NARCIS (Netherlands)

    Peighambardoust, S.H.; Fallah, E.; Hamer, R.J.; Goot, van der A.J.

    2010-01-01

    The effect of steady shearing versus z-blade mixing on mechanical aeration and gas retaining ability of the dough during processing and subsequent proofing and bread baking stages was investigated. Reduction in moisture content led to reduction in both static and dynamic densities of z-blade mixed d

  9. Fin characteristics of aerator devices with lateral deflectors

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LI Dan; MA Fei; QIAN Shang-tuo

    2013-01-01

    The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed,and the flow regime downstream of the aerator device will be worsened.In this paper,the height and the length of the fins induced by the lateral deflectors are theoretically analyzed along with their influencing factors,and the fin characteristics are experimentally investigated on the basis of the theoretical analysis.It is shown that the intensities of the fins are strongly dependent on the ratio of the lateral cavity length to the bottom cavity length,and other factors,like the working head,the height and the angle of the lateral deflector,the flow Froude number around the aerator device,affect the fins indirectly through the changes of the lateral cavity length.When an aerator device with lateral deflectors is designed,it is crucial to match the above mentioned ratio,and to make the ratio of the two cavity lengths less than 1.0 in order to avoid the generation of the fins.

  10. Internal aeration development and the zonation of plants in wetlands

    DEFF Research Database (Denmark)

    Sorrell, Brian Keith

    support many species which have root aeration adaptations but are otherwise unspecialised for aquatic life. Permanent standing water is a much greater challenge for plants, and survival here is restricted to species with special adaptations to their oxygen transport physiology such as the development...

  11. HYDRAULIC CHARACTERISTICS OF CHUTE AERATORS FOR RELEASE WORKS

    Institute of Scientific and Technical Information of China (English)

    RUAN Shi-ping

    2008-01-01

    On the basis of model tests and theoretical analysis, hydraulic characteristics, air demand, air concentration distribution and their relationships between prototype and model of an aerator were studied. Some computational examples show that the present methods have higher accuracy, and can meet the need of engineering design.

  12. Reduction of ripening time of full-scale manganese removal filters with manganese oxide-coated media

    NARCIS (Netherlands)

    Bruins, J.H.; Petrusevski, B.; Slokar, Y.M.; Huysman, K.; Joris, K.; Kruithof, J.C.; Kennedy, M.D.

    2015-01-01

    Effective manganese removal by conventional aeration-filtration with virgin filter media requires a long ripening time. The aim of this study was to assess the potential of manganese oxide-coated media to shorten the ripening time of filters with virgin media, under practical conditions. A full scal

  13. Enhancing filterability of activated sludge from landfill leachate treatment plant by applying electrical field ineffective on bacterial life.

    Science.gov (United States)

    Akkaya, Gulizar Kurtoglu; Sekman, Elif; Top, Selin; Sagir, Ece; Bilgili, Mehmet Sinan; Guvenc, Senem Yazici

    2017-03-09

    The aim of this study is to investigate filterability enhancement of activated sludge supplied form a full-scale leachate treatment plant by applying DC electric field while keeping the biological operational conditions in desirable range. The activated sludge samples were received from the nitrification tank in the leachate treatment plant of Istanbul's Odayeri Sanitary Landfill Site. Experimental sets were conducted as laboratory-scale batch studies and were duplicated for 1A, 2A, 3A, 4A, and 5A of electrical currents and 2, 5, 10, 15, and 30 min of exposure times under continuous aeration. Physicochemical parameters such as temperature, pH, and oxidation reduction potential in the mixture right after each experimental set and biochemical parameters such as chemical oxygen demand, total phosphorus, and ammonia nitrogen in supernatant were analyzed to define the sets that remain in the range of ideal biological operational conditions. Later on, sludge filterability properties such as capillary suction time, specific resistance to filtration, zeta potential, and particle size were measured for remaining harmless sets. Additionally, cost analyses were conducted in respect to energy and electrode consumptions. Application of 2A DC electric field and 15-min exposure time was found to be the most favorable conditions to enhance filterability of the landfill leachate-activated sludge.

  14. Effect of auxotrophies on yeast performance in aerated fed-batch reactor

    Energy Technology Data Exchange (ETDEWEB)

    Landi, Carmine; Paciello, Lucia [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy); Alteriis, Elisabetta de [Dept. Biologia Strutturale e Funzionale, Universita degli Studi di Napoli ' Federico II' , Via Cinthia, 80100 Napoli (Italy); Brambilla, Luca [Dept. Biotecnologie e Bioscienze, Universita Milano-Bicocca, Piazza della Scienza, 20126 Milano (Italy); Parascandola, Palma, E-mail: pparascandola@unisa.it [Dept. Ingegneria Industriale, Universita di Salerno, Via Ponte Don Melillo, 84084 Fisciano, Salerno (Italy)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer The paper contributes to fill the gap existing between the basic and applied research. Black-Right-Pointing-Pointer Mathematical model sheds light on the physiology of auxotrophic yeast strains. Black-Right-Pointing-Pointer Yeast behavior in fed-batch is influenced by biological and environmental determinants. Black-Right-Pointing-Pointer Process optimization would make possible the production of heterologous proteins which are not yet on the market. -- Abstract: A systematic investigation on the effects of auxotrophies on the performance of yeast in aerated fed-batch reactor was carried out. Six isogenic strains from the CEN.PK family of Saccharomyces cerevisiae, one prototroph and five auxotrophs, were grown in aerated fed-batch reactor using the same operative conditions and a proper nutritional supplementation. The performance of the strains, in terms of final biomass decreased with increasing the number of auxotrophies. Auxotrophy for leucine exerted a profound negative effect on the performance of the strains. Accumulation of reactive oxygen species (ROS) in the cells of the strain carrying four auxotrophies and its significant viability loss, were indicative of an oxidative stress response induced by exposure of cells to the environmental conditions. The mathematical model was fundamental to highlight how the carbon flux, depending on the number and type of auxotrophies, was diverted towards the production of increasingly large quantities of energy for maintenance.

  15. Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

    Science.gov (United States)

    Ding, Yi; Wang, Wei; Song, Xin-Shan; Wang, Gang; Wang, Yu-Hui

    2014-12-01

    The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%. It outperformed the unplanted or simple aerated system and was much better than non-aerated system. The study provided a strong evidence to support widespread research and application of spray aeration as a low-cost and energy-efficient aeration technology in V-SFCWs.

  16. Sequential Aeration of Membrane-Aerated Biofilm Reactors for High-Rate Autotrophic Nitrogen Removal: Experimental Demonstration

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Sun, Sheng-Peng; Lackner, Susanne;

    2010-01-01

    One-stage autotrophic nitrogen (N) removal, requiring the simultaneous activity of aerobic and anaerobic ammonium oxidizing bacteria (AOB and AnAOB), can be obtained in spatially redox-stratified biofilms. However, previous experience with Membrane-Aerated Biofilm Reactors (MABRs) has revealed...

  17. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast.

    Science.gov (United States)

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-05-10

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controlled aeration at -150, -100 and -50 mV levels; and constant aeration at 0.05 and 0.2 vvm. The results showed that anaerobic fermentation produced the least ethanol and had the highest residual glucose after 72 h of fermentation. Controlled aerations, depending on the real-time oxygen demand, led to higher cell viability than the no-aeration counterpart. Constant aeration triggered a quick biomass formation, and fast glucose utilization. However, over aeration at 0.2 vvm caused a reduction of final ethanol concentration. The controlled aeration driven by ORP under VHG conditions resulted in the best fermentation performance. Moreover, the controlled aeration could enhance yeast flocculating activity, promote an increase of flocs size, and accelerate yeast separation near the end of fermentation.

  18. Performance of completely autotrophic nitrogen removal over nitrite process under different aeration modes and dissolved oxygen

    Institute of Scientific and Technical Information of China (English)

    Jinsong GUO; Guohong YANG; Fang FANG; Yu QIN

    2008-01-01

    In this study, three sequential batch biofilm reactors (SBBRs) were operated for 155 days to evaluate the performance of completely autotrophic nitrogen removal over nitrite (CANON) process under different aeration modes and dissolved oxygen (DO). Synthetic wastewater with 160-mg NH4+-N/L was fed into the reac-tors. In the continuously-aerated reactor, the efficiency of the ammonium nitrogen conversion and total nitrogen (TN) removal reached 80% and 70%, respectively, with DO between 0.8-1.0 mg/L. Whereas in the intermit-tently-aerated reactor, at the aeration/non-aeration ratio of 1.0, ammonium was always under the detection limit and 86% of TN was removed with DO between 2.0 2.5 mg/L during the aeration time. Results show that CANON could be achieved in both continuous and inter-mittent aeration pattern. However, to achieve the same nitrogen removal efficiency, the DO needed in the inter-mittently-aerated sequential batch biofilm reactor (SBBR) during the aeration period was higher than that in the continuously-aerated SBBR. In addition, the DO in the CANON system should be adjusted to the aeration mode, and low DO was not a prerequisite to CANON process.

  19. The Effect of HLRs on Nitrogen Removal by Using a Pilot-scale Aerated Steel Slag System

    Directory of Open Access Journals (Sweden)

    Hamdan R.

    2017-01-01

    Full Text Available Discharge from domestic wastewater treatment plant amongst the main sources of nitrogen pollution in the environment. However, to remove nitrogen conventionally in domestic wastewater require high cost and complex chemical treatment method. Vertical flow aerated rock filter emerged as one of attractive alternative wastewater treatment method due to simplicity and compactness of the system. However, the application is yet to be developed in warm climate countries in particular Malaysia. Therefore, this study was conducted to investigate the effect of hydraulic loading rate (HLR to the performance of a pilot-scale Vertical Flow Aerated Rock Filter (VFARF in removing nitrogen from domestic wastewater using pilot-scale VFARF systems with steel slag as the filter media. Furthermore, this study has been designed to focus on the effects of two HLRs; 2.72 and 1.04 m3/m3.day. Influent and effluent of the filter systems were monitored biweekly basis for 11 weeks and analyzed for selected parameters. Results from this study shows that the VFARF with HLR 1.04 m3/m3.day has performed better in terms of removal ammonium-nitrogen and TKN as the system able to remove 90.4 ± 6.9%, 86.2 ± 10.7%, whilst the VFARF with 2.72 m3/m3.day remove 87.4 ± 9.9%, 80 ± 11.7%, respectively. From the observation, it can be concluded that nitrogen removal does affect by HLR as the removal in lower HLR system was higher due to high DO level in the VFARF system with 1.04 m3/m3.day which range from 4.5 to 5.1 mg/L whilst the DO level was slightly lower in the VFARF system with 2.72 m3/m3.day in the range of 3.7 to 4.5 mg/L.

  20. Phosphorus removal in aerated stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-03-01

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

  1. Molecular characterization of microbial populations in groundwater sources and sand filters for drinking water production.

    Science.gov (United States)

    de Vet, W W J M; Dinkla, I J T; Muyzer, G; Rietveld, L C; van Loosdrecht, M C M

    2009-01-01

    In full-scale drinking water production from groundwater, subsurface aeration is an effective means of enhancing the often troublesome process of nitrification. Until now the exact mechanism, however, has been unknown. By studying the microbial population we can improve the understanding of this process. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments of bacteria, archaea and ammonia-oxidizing bacteria was used to characterize the microbial populations in raw groundwater and trickling filters of an active nitrifying surface aerated system and an inactive non-surface aerated system. Only in the active filter were nitrifying microorganisms found above the detection limit of the method. In ammonia oxidation in this groundwater filter both bacteria and archaea played a role, while members belonging to the genus Nitrospira were the only nitrite-oxidizing species found. The subsurface aerated groundwater did not contain any of the nitrifying organisms active in the filter above the detection limit, but did contain Gallionella species that might play a major role in iron oxidation in the filter.

  2. BIOVENTING - Groundwater Aeration by Discontinuous Oxygen Gas Pulse Injections

    Science.gov (United States)

    Schirmer, M.

    2003-12-01

    Groundwater aeration by discontinuous oxygen gas pulse injections appears to be a promising concept for enhanced natural attenuation of dissolved contaminants that are susceptible for oxygenase enzyme attacks. Oxygen amendments facilitate indigenous microbiota to catabolize groundwater pollutants, such as aromatics, that are considered to be recalcitrant in absence of dissolved oxygen. As a rule, natural attenuation of many pollutants under aerobic conditions is considerably faster than under anaerobic conditions. Thus, enhancing the dissolved oxygen level appears to be worthwhile. In situ aeration of groundwater has been accomplished by air sparging, H2O2-supply, or by utilization of oxygen release compounds. However, continuous aeration of previously anaerobic groundwater is not desirable for several reasons: (a) economic efforts too high, (b) pollutant dislocation towards surface (desired only in air sparging), (c) risk of aquifer clogging (gas clogging, oxidation of ferrous iron, formation of bioslimes). In contrast, discontinuous oxygen gas sparging provides only for periodical groundwater aeration which is followed by microaerobic and suboxic conditions. Microaerobic conditions can prevail spatially (e.g., at plume fringes or within biofilms) or temporarily (e.g., at discontinuous bioventing). They still allow adapted bacteria to transform environmental pollutants to less toxic compounds, e.g., aromatic ring cleavage after dioxygenasis attack. Ring cleavage products, on the other hand, may be degraded more easily by anaerobic consortia than the initial aromatic compounds, making oxygen depletion periods highly intriguing in regard to an initiation of natural attenuation processes at plume fringes. In our work we outline the effect of oxygen depletion conditions on biodegradation of monchlorobenzene (MCB) as they occur subsequently to temporary aeration periods. For microaerobic conditions, relative to the oxygen supply, a stoichiometric transformation of MCB

  3. Optimal filtering

    CERN Document Server

    Anderson, Brian D O

    2005-01-01

    This graduate-level text augments and extends beyond undergraduate studies of signal processing, particularly in regard to communication systems and digital filtering theory. Vital for students in the fields of control and communications, its contents are also relevant to students in such diverse areas as statistics, economics, bioengineering, and operations research.Topics include filtering, linear systems, and estimation; the discrete-time Kalman filter; time-invariant filters; properties of Kalman filters; computational aspects; and smoothing of discrete-time signals. Additional subjects e

  4. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    Science.gov (United States)

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

  5. Soil aeration status in a lowland wet grassland

    Science.gov (United States)

    Barber, K. R.; Leeds-Harrison, P. B.; Lawson, C. S.; Gowing, D. J. G.

    2004-02-01

    The maintenance or development of plant community diversity in species-rich wet grasslands has been a focus of water management considerations in the UK for the past 20 years. Much attention has been given to the control of water levels in the ditch systems within these wet grassland systems. In this paper we report measurements of aeration status and water-table fluctuation made on a peat soil site at Tadham Moor in Somerset, UK, where water management has focused on the maintenance of wet conditions that often result in flooding in winter and wet soil conditions in the spring and summer. Measurement and modelling of the water-table fluctuation indicates the possibility of variability in the aeration of the root environment and anoxic conditions for much of the winter period and for part of the spring and summer. We have used water content and redox potential measurements to characterize the aeration status of the peat soil. We find that air-filled porosity is related to water-table depth in these situations. Redox potentials in the spring were generally found to be low, implying a reducing condition for nitrate and iron. A significant relationship (p < 0.01) between redox potential and water-table depth exists for data measured at 0.1 m depth, but no relationship could be found for data from 0.4 m depth.

  6. Development of a novel membrane aerated hollow-fiber microbioreactor.

    Science.gov (United States)

    Villain, Louis; Meyer, Lina; Kroll, Stephen; Beutel, Sascha; Scheper, Thomas

    2008-01-01

    A new challenge in biotechnological processes is the development of flexible bioprocessing platforms, allowing strain selection, facilitating scale-up and integrating separation steps. Miniaturization of such a cultivation system allows parallel use and the saving of resources but makes the supply of oxygen to the cells difficult. In this work we present a membrane aerated hollow-fiber microbioreactor (HFMBR) which consists of an acrylic glass module equipped with two different types of membrane fibers. Fibers of polyethersulfone and polyvinyldifluoride were used for substrate and oxygen supply, respectively. Cultivation of E. coli as model organism and production of His-tagged GFP were carried out in the extracapillary space of the membrane aerated HFMBR and compared with cultivations in shaking flask which are commonly used for screening experiments. The measurement of the oxygen transfer capacity and the online monitoring of the dissolved oxygen during the cultivation were performed using a fiber optic oxygen sensor. Online measurement of the optical density was also integrated to the bioreactor. Due to efficient oxygen transfer, a better cell growth than in the shaking flask experiments was achieved, while no negative influence on the GFP productivity was observed in the membrane aerated bioreactor. Thus the feasibility of a future integrated downstreaming could also be demonstrated.

  7. Emissions of ammonia, carbon dioxide, and hydrogen sulfide from swine wastewater during and after acidification treatment: effect of pH, mixing and aeration.

    Science.gov (United States)

    Dai, X R; Blanes-Vidal, V

    2013-01-30

    This study aimed at evaluating the effect of swine slurry acidification and acidification-aeration treatments on ammonia (NH(3)), carbon dioxide (CO(2)) and hydrogen sulfide (H(2)S) emissions during slurry treatment and subsequent undisturbed storage. The study was conducted in an experimental setup consisting of nine dynamic flux chambers. Three pH levels (pH = 6.0, pH = 5.8 and pH = 5.5), combined with short-term aeration and venting (with an inert gas) treatments were studied. Acidification reduced average NH(3) emissions from swine slurry stored after acidification treatment compared to emissions during storage of non-acidified slurry. The reduction were 50%, 62% and 77% when pH was reduce to 6.0, 5.8 and 5.5, respectively. However, it had no significant effect on average CO(2) and H(2)S emissions during storage of slurry after acidification. Aeration of the slurry for 30 min had no effect on average NH(3), CO(2) and H(2)S emissions both during the process and from stored slurry after venting treatments. During aeration treatment, the NH(3), CO(2) and H(2)S release pattern observed was related to the liquid turbulence caused by the gas bubbles rather than to biological oxidation processes in this study.

  8. 接触氧化-曝气生物滤池组合工艺处理洗涤剂废水试验研究%THE EXPERIMENTAL STUDY ON BIOLOGICAL CONTACT OXIDATION-BIOLOGICAL AERATED FILTER COMBINED PROCESS IN SYNTHETIC DETERGENT WASTEWATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    萧灿强; 胡晓东; 陈嘉祺; 石云峰; 李海燕; 郭俊

    2013-01-01

    采用生物接触氧化联合曝气生物滤池(BAF)组合工艺处理合成洗涤废水.考察了生物悬浮填料(MBBR填料)的挂膜启动时间,有机负荷对COD去除效果的影响以及DO、HRT、组合工艺对LAS处理效果的影响.结果表明,在接触氧化阶段HRT为20 h、DO的质量浓度为3.0 mg/L、BAF阶段HRT为1.2 h、DO的质量浓度为4.0 mg/L的优化条件下,保持试验系统连续运行20d,出水水质可达广东省地方标准DB 44/26-2001的第一时段一级标准.

  9. Effects of aeration position on organics, nitrogen and phosphorus removal in combined oxidation pond-constructed wetland systems.

    Science.gov (United States)

    Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua; Peng, Sen; Wu, Qing; Yan, Lijian

    2015-12-01

    Given that few studies investigated the effects of aeration position (AP) on the performance of aerated constructed wetlands, the aim of this study was to evaluate the effects of AP on organics, nitrogen and phosphorus removal in lab-scale combined oxidation pond-constructed wetland (OP-CW) systems. Results showed that middle aeration allowed the CW to possess more uniform oxygen distribution and to achieve greater removals of COD and NH3-N, while the CW under bottom aeration and surface aeration demonstrated more distinct stratification of oxygen distribution and surface aeration brought about better TN removal capacity for the OP-CW system. However, no significant influence of artificial aeration or AP on TP removal was observed. Overall, AP could significantly affect the spatial distribution of dissolved oxygen by influencing the oxygen diffusion paths in aerated CWs, thereby influencing the removal of pollutants, especially organics and nitrogen, which offers a reference for the design of aerated CWs.

  10. Experience of drilling wells using pump-compressor unit to inject aerated fluid

    Energy Technology Data Exchange (ETDEWEB)

    Oleynik, S.P.; Beley, I.V.; Lopatin, Yu.S.; Pytel, S.P.; Vasilak, I.I.; Yushkevich, V.I.

    1979-01-01

    Results are described from drilling wells with flushing by highly aerated clay fluid with the help of a UNGA unit which includes pumps and compressors of the drilling unit UBSh-1 which permits injection of an aerated mixture under pressures considerably exceeding the pressure of its formation. Qualitative and technical-economic advantages of drilling with flushing by aerated solutions with the use of a unit for injecting gas-liquid agents are presented.

  11. Aeration-Induced Changes in Temperature and Nitrogen Dynamics in a Dimictic Lake.

    Science.gov (United States)

    Holmroos, Heidi; Horppila, Jukka; Laakso, Sanna; Niemistö, Juha; Hietanen, Susanna

    2016-07-01

    Low levels of oxygen (O) in the hypolimnion layer of lakes are harmful to benthic animals and fish; they may also adversely affect nutrient cycles. Artificial aeration is often used in lake management to counteract these problems, but the effects of aeration on nitrogen (N) cycling are not known. We studied the effects of hypolimnetic aeration on N dynamics and temperature in a eutrophic lake by comparing continuous and pulsed aeration with a nonaerated station. Aeration decreased the accumulation of NH-N deep in the lake (20-33 m) by supplying O for nitrification, which in turn provided substrate for denitrification and promoted N removal. Aeration also increased the temperature in the hypolimnion. Denitrification rate was highest in the nonaerated deep areas (average, 7.62 mg N m d) due to very high rates during spring turnover of the water column, demonstrating that natural turnover provides O for nitrification. During stratification, denitrification was highest at the continuously aerated station (4.06 mg N m d) and lowest at the nonaerated station (3.02 mg N m d). At the periodically aerated station, aeration pauses did not restrict the increase in temperature but resulted in accumulation of NH-N and decreased the contribution of denitrification as a nitrate reduction process. Our findings demonstrate that hypolimnetic aeration can substantially affect N cycling in lakes and that the effect depends on the aeration strategy. Because N is one of the main nutrients controlling eutrophication, the effects of aeration methods on N removal should be considered as part of strategies to manage water quality in lakes.

  12. Rapid Start-up and Loading of an Attached Growth, Simultaneous Nitrification/Denitrification Membrane Aerated Bioreactor

    Science.gov (United States)

    Meyer, Caitlin E.; Pensinger, Stuart; Pickering, Karen D.; Barta, Daniel; Shull, Sarah A.; Vega, Letticia M.; Christenson, Dylan; Jackson, W. Andrew

    2015-01-01

    Membrane aerated bioreactors (MABR) are attached-growth biological systems used for simultaneous nitrification and denitrification to reclaim water from waste. This design is an innovative approach to common terrestrial wastewater treatments for nitrogen and carbon removal and implementing a biologically-based water treatment system for long-duration human exploration is an attractive, low energy alternative to physiochemical processes. Two obstacles to implementing such a system are (1) the "start-up" duration from inoculation to steady-state operations and (2) the amount of surface area needed for the biological activity to occur. The Advanced Water Recovery Systems (AWRS) team at JSC explored these two issues through two tests; a rapid inoculation study and a wastewater loading study. Results from these tests demonstrate that the duration from inoculation to steady state can be reduced to under two weeks, and that despite low ammonium removal rates, the MABRs are oversized.

  13. Nitrogen-removal performance and community structure of nitrifying bacteria under different aeration modes in an oxidation ditch.

    Science.gov (United States)

    Guo, Chang-Zi; Fu, Wei; Chen, Xue-Mei; Peng, Dang-Cong; Jin, Peng-Kang

    2013-07-01

    Oxidation-ditch operation modes were simulated using sequencing batch reactors (SBRs) with alternate stirring and aerating. The nitrogen-removal efficiencies and nitrifying characteristics of two aeration modes, point aeration and step aeration, were investigated. Under the same air-supply capacity, oxygen dissolved more efficiently in the system with point aeration, forming a larger aerobic zone. The nitrifying effects were similar in point aeration and step aeration, where the average removal efficiencies of NH4(+) N were 98% and 96%, respectively. When the proportion of anoxic and oxic zones was 1, the average removal efficiencies of total nitrogen (TN) were 45% and 66% under point aeration and step aeration, respectively. Step aeration was more beneficial to both anoxic denitrification and simultaneous nitrification and denitrification (SND). The maximum specific ammonia-uptake rates (AUR) of point aeration and step aeration were 4.7 and 4.9 mg NH4(+)/(gMLVSS h), respectively, while the maximum specific nitrite-uptake rates (NUR) of the two systems were 7.4 and 5.3 mg NO2(-)-N/(gMLVSS h), respectively. The proportions of ammonia-oxidizing bacteria (AOB) to all bacteria were 5.1% under point aeration and 7.0% under step aeration, and the proportions of nitrite-oxidizing bacteria (NOB) reached 6.5% and 9.0% under point and step aeration, respectively. The dominant genera of AOB and NOB were Nitrosococcus and Nitrospira, which accounted for 90% and 91%, respectively, under point aeration, and the diversity of nitrifying bacteria was lower than under step aeration. Point aeration was selective of nitrifying bacteria. The abundance of NOB was greater than that of AOB in both of the operation modes, and complete transformation of NH4(+) N to NO3(-)-N was observed without NO2(-)-N accumulation.

  14. Violent breaking wave impacts. Part 3. Effects of scale and aeration

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Bullock, G. N.; Hogg, A. J.

    2015-01-01

    . The Bagnold-Mitsuyasu scaling law for the compression of an air pocket by a piston of incompressible water is rederived and generalised to 3D air pockets of arbitrary shape. Numerical results for wall pressure, force and impulse are then presented for a flip-through impact, a low-aeration impact and a high......-aeration impact, for nine scales and five levels of initial aeration. Two of these impact types trap a pocket of air at the wall. Among the findings of the paper is that for fixed initial aeration, impact pressures from the flip-through impact broadly follow Froude scaling. This is also the case for the two...

  15. Monitoring transitory profiles of leachate humic substances in landfill aeration reactors in mesophilic and thermophilic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Huanhuan [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Yin, Ke; Ge, Liya; Giannis, Apostolos [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); Chuan, Valerie W.L. [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Wang, Jing-Yuan, E-mail: JYWANG@ntu.edu.sg [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore)

    2015-04-28

    Highlights: • Polymerization and condensation of humic substances (HS) were enhanced by aeration. • Carboxylic group was enriched in HS by aeration presenting improved hydrophilicity. • Mobility of humic acid, as a result was enhanced by aeration especially in young landfill. • Waste age plays an important role in leachate management during aeration. - Abstract: The presence of humic substances (HS) in landfill leachate is of great interest because of their structural stability and potential toxicity. This study examined the effects of temperature and waste age on the transformation of HS during in situ aeration of bioreactor landfills. By establishing aerobic conditions, dissolved organic carbon (DOC) rapidly accumulated in the bioreactor leachate. Fractional analysis showed that the elevated concentration of humic acids (HAs) was primarily responsible for the increment of leachate strength. Further structural characterization indicated that the molecular weight (MW) and aromacity of HS were enhanced by aeration in conjunction with thermophilic temperature. Interestingly, elevation of HAs concentration was not observed in the aeration reactor with a prolonged waste age, as the mobility of HAs was lowered by the high MW derived from extended waste age. Based on these results, aeration may be more favorable in aged landfills, since dissolution of HAs could be minimized by the evolution to larger MW compared to young landfills. Moreover, increased operation temperature during aeration likely offers benefits for the rapid maturation of HS.

  16. Partial nitritation ANAMMOX in submerged attached growth bioreactors with smart aeration at 20 °C.

    Science.gov (United States)

    Shannon, James M; Hauser, Lee W; Liu, Xikun; Parkin, Gene F; Mattes, Timothy E; Just, Craig L

    2015-01-01

    Submerged attached growth bioreactors (SAGBs) were operated at 20 °C for 30 weeks in smart-aerated, partial nitritation ANAMMOX mode and in a timer-controlled, cyclic aeration mode. The smart-aerated SAGBs removed 48-53% of total nitrogen (TN) compared to 45% for SAGBs with timed aeration. Low dissolved oxygen concentrations and cyclic pH patterns in the smart-aerated SAGBs suggested conditions favorable to partial nitritation ANAMMOX and stoichiometrically-derived and numerically modeled estimations attributed 63-68% and 14-44% of TN removal to partial nitritation ANAMMOX in these bioreactors, respectively. Ammonia removals of 36-67% in the smart-aerated SAGBs, with measured oxygen and organic carbon limitations, further suggest partial nitritation ANAMMOX. The smart-aerated SAGBs required substantially less aeration to achieve TN removals similar to SAGBs with timer-controlled aeration. Genomic DNA testing confirmed that the dominant ANAMMOX seed bacteria, received from a treatment plant utilizing the DEMON® sidestream deammonification process, was a Candidatus Brocadia sp. (of the Planctomycetales order). The DNA from these bacteria was also present in the SAGBs at the conclusion of the study providing evidence for attached growth and limited biomass washout.

  17. Microstructure and Properties of Silty Siliceous Crushed Stone-lime Aerated Concrete

    Institute of Scientific and Technical Information of China (English)

    WANG Qiankun; CHEN Youzhi; LI Fangxian; SUN Tao; XU Bingbo

    2006-01-01

    The clayish crushed stone was used for making aerated concrete. Through studying hydro-thermal synthesis reaction, mix ratio, gas-forming and performance analysis, Grade-B05 and Grade-B06 aerated concrete were prepared successfully. The proper mix ratio and key processing parameters were achieved. The microstructure of aerated concrete with crush stone was analyzed by means of XRD and SEM. The experimental results indicate that the hydration products are poorly crystalline C-S-H (B), tobermorite and hydrogarnet. No component of clay was found. Unreacted SiO2 can be in existence, and the structure system of aerated concrete is homogeneous and dense.

  18. [Effect of aeration intensity on the nitrogen and phosphorus removal performance of AOA membrane bioreactors].

    Science.gov (United States)

    Chen, Xiao-Yang; Xue, Zhi-Yong; Xiao, Jing-Ni; Zhang, Han-Min; Yang, Feng-Lin; Wang, Wei-Ping; Hong, Chun-Lai; Zhu, Feng-Xiang

    2011-10-01

    The ability of simultaneous phosphorus and nitrogen removal of sequencing batch membrane bioreactor run in anaerobic/oxic/ anoxic mode (AOA MBR) was examined under three aeration intensities [2.5, 3.75 and 5.0 m3 x (m2 x h)(-10]. The results showed that the averaged removals of COD were over 90% at different aeration intensities. And the higher aeration intensity was, the more ammonia nitrogen removal rate achieved. The removal rates of NH4(+) under the three aeration intensities were 84.7%, 90.6% and 93.8%, respectively. Total nitrogen removal rate increased with the increasing aeration intensity. But excessive aeration intensity reduced TN removal. The removal rates of TN under the three aeration intensities were 83.4%, 87.4% and 80.6%, respectively. Aeration intensity affected the denitrifying phosphorus ability of the AOA MBR. The ratio of denitrification phosphorus removal under the three aeration intensities were 20%, 30.2% and 26.7%, respectively.

  19. Ultraviolet filters.

    Science.gov (United States)

    Shaath, Nadim A

    2010-04-01

    The chemistry, photostability and mechanism of action of ultraviolet filters are reviewed. The worldwide regulatory status of the 55 approved ultraviolet filters and their optical properties are documented. The photostabilty of butyl methoxydibenzoyl methane (avobenzone) is considered and methods to stabilize it in cosmetic formulations are presented.

  20. Rapid Startup and Loading of an Attached Growth, Simultaneous Nitrification/Denitrification Membrane Aerated Bioreactor

    Science.gov (United States)

    Meyer, Caitlin; Vega, Leticia

    2014-01-01

    The Membrane Aerated Bioreactor (MABR) is an attached-growth biological system for simultaneous nitrification and denitrification. This design is an innovative approach to common terrestrial wastewater treatments for nitrogen and carbon removal. Implementing a biologically-based water treatment system for long-duration human exploration is an attractive, low energy alternative to physiochemical processes. Two obstacles to implementing such a system are (1) the "start-up" duration from inoculation to steady-state operations and (2) the amount of surface area needed for the biological activity to occur. The Advanced Water Recovery Systems (AWRS) team at JSC explored these two issues through two tests; a rapid inoculation study and a wastewater loading study. Results from these tests demonstrate that the duration from inoculation to steady state can be reduced to two weeks and that the surface area to volume ratio baseline used in the Alternative Water Processor (AWP) test was higher than what was needed to remove the organic carbon and ammonium from the system.

  1. Pseudomonads rule degradation of polyaromatic hydrocarbons in aerated sediment

    Directory of Open Access Journals (Sweden)

    Jiri eWald

    2015-11-01

    Full Text Available Given that the degradation of aromatic pollutants in anaerobic environments such as sediment is generally very slow, aeration could be an efficient bioremediation option. Using stable isotope probing (SIP coupled with pyrosequencing analysis of 16S rRNA genes, we identified naphthalene-utilizing populations in aerated polyaromatic hydrocarbon (PAH-polluted sediment. The results showed that naphthalene was metabolized at both 10°C and 20°C following oxygen delivery, with increased degradation at 20°C as compared to 10°C – a temperature more similar to that found in situ. Naphthalene-derived 13C was primarily assimilated by pseudomonads. Additionally, Stenotrophomonas, Acidovorax, Comamonas and other minor taxa were determined to incorporate 13C throughout the measured time course. The majority of SIP-detected bacteria were also isolated in pure cultures, which facilitated more reliable identification of naphthalene-utilizing populations as well as proper differentiation between primary consumers and cross-feeders. The pseudomonads acquiring the majority of carbon were identified as Pseudomonas veronii and P. gessardii. Stenotrophomonads and Acidovorax defluvii, however, were identified as cross-feeders unable to directly utilize naphthalene as a growth substrate. PAH degradation assays with the isolated bacteria revealed that all pseudomonads as well as Comamonas testosteroni degraded acenaphthene, fluorene and phenanthrene in addition to naphthalene. Furthermore, P. veronii and C. testosteroni were capable of transforming anthracene, fluoranthene and pyrene. Screening of isolates for naphthalene dioxygenase genes using a set of in-house designed primers for Gram-negative bacteria revealed the presence of such genes in pseudomonads and Comamonas testosteroni. Overall, our results indicated an apparent dominance of pseudomonads in the sequestration of carbon from naphthalene and potential degradation of other PAHs upon aeration of the

  2. Comparison of Biomass and Lipid Production under Ambient Carbon Dioxide Vigorous Aeration and 3% Carbon Dioxide Condition Among the Lead Candidate Chlorella Strains Screened by Various Photobioreactor Scales

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Naoko [Univ. of Nebraska, Lincoln, NE (United States); Barnes, Austin [Univ. of Nebraska, Lincoln, NE (United States); Jensen, Travis [Univ. of Nebraska, Lincoln, NE (United States); Noel, Eric [Univ. of Nebraska, Lincoln, NE (United States); Andlay, Gunjan [Synaptic Research, Baltimore, MD (United States); Rosenberg, Julian N. [Johns Hopkins Univ., Baltimore, MD (United States); Betenbaugh, Michael J. [Johns Hopkins Univ., Baltimore, MD (United States); Guarnieri, Michael T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Oyler, George A. [Univ. of Nebraska, Lincoln, NE (United States); Johns Hopkins Univ., Baltimore, MD (United States); Synaptic Research, Baltimore, MD (United States)

    2015-09-01

    Chlorella species from the UTEX collection, classified by rDNA-based phylogenetic analysis, were screened based on biomass and lipid production in different scales and modes of culture. Lead candidate strains of C. sorokiniana UTEX 1230 and C. vulgaris UTEX 395 and 259 were compared between conditions of vigorous aeration with filtered atmospheric air and 3% CO2 shake-flask cultivation. We found that the biomass of UTEX 1230 produced 2 times higher at 652 mg L-1 dry weight under both ambient CO2 vigorous aeration and 3% CO2 conditions, while UTEX 395 and 259 under 3% CO2 increased to 3 times higher at 863 mg L-1 dry weight than ambient CO2 vigorous aeration. The triacylglycerol contents of UTEX 395 and 259 increased more than 30 times to 30% dry weight with 3% CO2, indicating that additional CO2 is essential for both biomass and lipid accumulation in UTEX 395 and 259.

  3. DIGITAL IMAGE MEASUREMENT OF BUBBLE MOTION IN AERATED WATER FLOWS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Digital image measurement method, as an ex-tension of Particle Image Velocimetry of single-phase flowmeasurement, was investigated for application to air-watertwo-phase flows. The method has strong potential ability inmeasuring bubble geometrical features and moving velocitiesfor complex bubble motion in aerated water flow. Both dilutedand dense bubble rising flows are measured using the digitalimage method. Measured bubble shapes and sizes, and bubblevelocities are affected by threshold selection for binary image.Several algorithms for selecting threshold are compared andmethods for calculating the time-averaged void fraction arediscussed.

  4. Pulverizing aeration as a method of lakes restoration

    Science.gov (United States)

    Kaczorowska, E.; Podsiadłowski, S.

    2012-04-01

    The principal threat to lakes of the temperate zone is posed by factors accelerating their eutrophication and causing marked deoxygenation of the deeper layers of water, mainly the hypo- and metalimnion. Among their effects are frequent phytoplankton blooms, including those of blue-green algae, and general deterioration of water quality also affecting the abundance and health status of fish. The chief concern is a disturbed proportion between the amount of complex chemical compounds, especially organic, and the oxygen content of lake waters. Natural processes of water oxygenation are not too intensive, because they are practically limited to the epilimnion layer, connected as they are with the activity of aquatic plants of the littoral and sublittoral zone (which tends to disappear in contaminated lakes) and wind energy (the effect of waving). In summer conditions, with a relatively great chemical activity of bottom deposits, the intensity of those processes is usually inadequate. Hence, in 1995 a research was launched in the Institute of Agricultural Engineering of the Agricultural University in Poznań on an integrated lake restoration technology whose core was a self-powered aerator capable of oxygenating also the bottom layers of water (the hypolimnion) of deep lakes. The aerator uses energy obtained from a Savonius rotor mainly to diffuse gases: to release hydrogen sulphide, which usually saturates the hypolimnion water completely, and then to saturate this water with oxygen. Even early studies showed the constructed device to be highly efficient in improving oxygen conditions in the bottom zone. They also made it clear that it should be equipped with an autonomous system designed to inactivate phosphorus, one of the principal factors determining the rate of lake degradation. In 2003 the first wind-driven pulverising aerator equipped with such a system was installed in Town Lake in Chodzież. The aim of this work is to present the principles of operation of a

  5. Modelling and test of aeration tank settling (ATS)

    DEFF Research Database (Denmark)

    Nielsen, M. K.; Bechmann, H.; Henze, Mogens

    2000-01-01

    that a qualitatively correct model can be established. The simplicity of the model allows for on-line identification of the necessary parameters, so that no maintenance is needed to use of the on-line model for control. The practical implementation on three plants indicates that implementation of STAR with ATS control......The use of aeration tank settling during high hydraulic loads on large wastewater treatment plants has previously been demonstrated as a reliable technique and proven valuable. The paper proposes a simplified deterministic model to predict the efficiency of the method. It is shown...

  6. Development of Filter-Blower Unit for use in the Advanced Nuclear Biological Chemical Protection System (ANBCPS) Helicopter/Transport-aircraft version

    NARCIS (Netherlands)

    Sabel, R.; Reffeltrath, P.A.; Jonkman, A.; Post, T.

    2006-01-01

    As a participant in the three-nation partnership for development of the ANBCP-S for use in Helicopters, Transport Aircraft and Fast Jet, the Royal Netherlands Airforce (RNLAF) picked up the challenge to design a Filter- Blower-Unit (FBU). Major Command (MajCom) of the RNLAF set priority to develop a

  7. Food Filter

    Institute of Scientific and Technical Information of China (English)

    履之

    1995-01-01

    A typical food-processing plant produces about 500,000 gallons of waste water daily. Laden with organic compounds, this water usually is evaporated or discharged into sewers.A better solution is to filter the water through

  8. Galvanic corrosion of nitinol under deaerated and aerated conditions.

    Science.gov (United States)

    Pound, Bruce G

    2016-10-01

    Various studies have examined the corrosion rate of nitinol generally under deaerated conditions. Likewise, galvanic corrosion studies have typically involved deaerated solutions. This work addressed the effect of galvanic coupling on the corrosion current of electropolished nitinol in phosphate buffered saline and 0.9% sodium chloride under dearated and aerated conditions for times up to 24 h. Tests were performed on nitinol alone and coupled with MP35N in both the mechanically polished and passivated conditions. Aeration and galvanic coupling were found to have relatively little effect, indicating that the corrosion current is controlled by the anodic reaction. The current can be attributed entirely to Ni(2+) dissolution, which appears to be governed by solid-state mass transport of Ni(2+) through the passive oxide film. Because corrosion of EP nitinol is controlled by the anodic reaction, contact between EP nitinol and MP35N or other biomedical Co-Cr alloys is unlikely to result in significant galvanic effects in vivo. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1322-1327, 2016.

  9. Water quality and bacteriology in an aquaculture facility equipped with a new aeration system

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, S.O.; Kulkarni, S.S.; Shirodkar, R.R.; Karekar, S.V.; PraveenKumar, R.; Sreepada, R.A.; Vogelsang, C.; LokaBharathi, P.A.

    l sup(-1). Non-aerated conditions promoted denitrification maintaining nitrate concentration between 0.32 and 0.98 Mu M NO sub(3) sup(-) - N l sup(-1). However, a marked increase in ammonium content was observed in the non-aerated pond at the end...

  10. Surfactant effects on alpha factors in full-scale wastewater aeration systems.

    Science.gov (United States)

    Rosso, D; Larson, L E; Stenstrom, M K

    2006-01-01

    Aeration is an essential process in the majority of wastewater treatment processes, and accounts for the largest fraction of plant energy costs. Aeration systems can achieve wastewater oxygenation by shearing the surface (surface aerators) or releasing bubbles at the bottom of the tank (coarse- or fine-bubble aerators). Surfactants accumulate on gas-liquid interfaces and reduce mass transfer rates. This reduction in general is larger for fine-bubble aerators. This study was conducted to evaluate mass transfer effects on the characterization and specification of aeration systems in clean and process water conditions. Tests at different interfacial turbulence regimes were analysed, showing higher gas transfer depression for lower turbulence regimes. Higher turbulence regimes can offset contamination effects, at the expense of operating efficiency. This phenomenon is characteristic of surface aerators and coarse bubble diffusers and is here discussed. The results explain the variability of alpha factors measured at small scale, due to uncontrolled energy density. Results are also reported in dimensionless empirical correlations that describe mass transfer as a function of physiochemical and geometrical characteristics of the aeration process.

  11. Effect of new aeration technology on the bacteriology of shrimp ponds growing Penaeus monodon

    Digital Repository Service at National Institute of Oceanography (India)

    Karekar, S.V.; Sreepada, R.A.; Shirodkar, R.R.; Kulkarni, S.; Kumar, P.; LokaBharathi, P.A.; Bergheim, A.; Vogelsang, C.

    , particularly the disease causing bacteria in response to aeration during the cultivation of tiger shrimp, Penaeus monodon. In HOBAS aerated pond (P1) showed more stable DO levels and the pond sediment was healthier with no visual black sulphur deposits. However...

  12. 40 CFR 265.278 - Unsaturated zone (zone of aeration) monitoring.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Unsaturated zone (zone of aeration) monitoring. 265.278 Section 265.278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., STORAGE, AND DISPOSAL FACILITIES Land Treatment § 265.278 Unsaturated zone (zone of aeration)...

  13. Sequentially aerated membrane biofilm reactors for autotrophic nitrogen removal: microbial community composition and dynamics

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Franck, Stephanie; Gülay, Arda;

    2014-01-01

    Membrane-aerated biofilm reactors performing autotrophic nitrogen removal can be successfully applied to treat concentrated nitrogen streams. However, their process performance is seriously hampered by the growth of nitrite oxidizing bacteria (NOB). In this work we document how sequential aeration...

  14. Evaluation of re-aeration equations for river Ghataprabha, Karnataka, India and development of refined equation.

    Science.gov (United States)

    Kalburgi, P B; Jha, R; Ojha, C S P; Deshannavar, U B

    2015-01-01

    Stream re-aeration is an extremely important component to enhance the self-purification capacity of streams. To estimate the dissolved oxygen (DO) present in the river, estimation of re-aeration coefficient is mandatory. Normally, the re-aeration coefficient is expressed as a function of several stream variables, such as mean stream velocity, shear stress velocity, bed slope, flow depth and Froude number. Many empirical equations have been developed in the last years. In this work, 13 most popular empirical re-aeration equations, used for re-aeration prediction, have been tested for their applicability in Ghataprabha River system, Karnataka, India, at various locations. Extensive field data were collected during the period March 2008 to February 2009 from seven different sites located in the river to observe re-aeration coefficient using mass balance approach. The performance of re-aeration equations have been evaluated using various error estimations, namely, the standard error (SE), mean multiplicative error (MME), normalized mean error (NME) and correlation statistics. The results show that the predictive equation developed by Jha et al. (Refinement of predictive re-aeration equations for a typical Indian river. Hydrological Process. 2001;15(6):1047-1060), for a typical Indian river, yielded the best agreement with the values of SE, MME, NME and correlation coefficient r. Furthermore, a refined predictive equation has been developed for river Ghataprabha using least-squares algorithm that minimizes the error estimates.

  15. Experimental investigations of aeration efficiency in high-head gated circular conduits.

    Science.gov (United States)

    Cihat Tuna, M; Ozkan, Fahri; Baylar, Ahmet

    2014-01-01

    The primary purpose of water aeration is to increase the oxygen saturation of the water. This can be achieved by using hydraulic structures because of substantial air bubble entrainment at these structures. Closed conduit aeration is a particular instance of this. While there has been a great deal of research on air-demand ratio within closed conduit, very little research has specifically addressed aeration efficiency of closed conduit. In the present work an experimental study was conducted to investigate the aeration efficiency of high-head gated circular conduits. Results showed that high-head gated circular conduits were effective for oxygen transfer. The effects of Froude number and ratio of the water cross-sectional flow area to the conduit cross-sectional area on aeration efficiency were particularly significant, whereas the effect of conduit length was only moderate. Further, a design formula for the aeration efficiency was presented relating the aeration efficiency to ratio of water cross-sectional flow area to conduit cross-sectional area and Froude number. The obtained results will be useful in future modeling processes and aid the practicing engineer in predicting aeration efficiency for design purposes.

  16. EXPERIMENTAL STUDY ON A NEW TYPE OF AERATOR IN SPILLWAY WITH LOW FROUDE NUMBER AND MILD SLOPE FLOW

    Institute of Scientific and Technical Information of China (English)

    SU Pei-lan; LIAO Hua-sheng; QIU Yue; LI Chen-juan

    2009-01-01

    Experimental study on aeration characteristics of various aeration devices was conducted in the spillway tunnel of the Pubugou hydropower project, Sichuan Province, China. It is shown by comparison that the new type of aeration device, namely, the aerator with a trapezoidal-shaped slot and a steep-slope section(ATSS), can avoid water accumulation in the cavity of the aeration device in the project, thus can effectively solve the backwater problems arising from this project and be used for a wide range of different water levels, without any drain facilities. Above the water level of 840 m, the water contained in the cavity can be eliminated completely, which means that the recommended new type of aerator can meet the aeration demands in the spillway of the project with low Froude number and may be of practical significance and of interest to other projects with similar types of aeration devices.

  17. Experimental Study on Characteristics of Biological Filter with Combination Packing for Removal C, N and P from Sewage%组合填料生物滤床处理污水脱碳氮磷性能试验

    Institute of Scientific and Technical Information of China (English)

    赵玉华; 赵杰; 李艳凤; 徐丽

    2011-01-01

    目的 深度处理模拟城市污水厂二级出水,考察对磷、有机物及氨氮的去除效果.方法 选取沸石、钢渣、煤灰渣、硅藻土4种填料,采用不同的组合方式构建4个填料生物滤池,在试验滤速0.65 m/d的条件下,利用组合填料生物滤床的物理、化学和生物的协同作用,通过填料层过滤、吸附、共沉、离子交换和微生物的分解.结果 装有钢渣填料的滤柱除磷效果较好.沸石、钢渣、硅藻土组合方式填料滤柱对磷、碳、氨氮的去除效果均较高,磷的平均去除率93.68%,氨氮平均去除率86.1%,CODCr平均去除率62.7%.而沸石与煤渣组合滤柱、或沸石、煤渣、硅藻土组合滤柱除磷效果较差.结论 下向流组合填料滤床处理模拟城市污水厂二级出水最佳填料组合方案:从上至下,沸石、钢渣、硅藻土.%Municipal secondary effluent was treated deeply,to investigate removal efficiency to phosphorus, organic pollutants and ammonia nitrogen. Four packing bio-filters was built by selecting zeolite,steel slag, coal ash and diatomite, using different packing combination way. In the test we set the biological filter by filtration, adsorption, precipitation, ion exchange and microbial decomposition. With physical,chemical,biological synergy of biological filter with combination packing, the test filtering velocity was 0. 65 meters per hour. Effect of phosphorus removal was high by filters packed steel slag. Average phosphorus removal rate was 93. 68 percent,ammonia nitrogen 86. 1 percent and 62. 7 percent,so all the rates was high velocity ,0. 65 meters per hour. But filters packed zeolite,coal cinder or zeolite,coal cinder and diatomite have a poor removal effect for phosphorus. The best combination scheme for packing bed in the down-flow bio-filter is zeolite, steel slag and diatomite from top to bottom to treat municipal secondary effluent.

  18. EXPERIMENTAL INVESTIGATION ON SOUND SPEED PROPAGATING THROUGH HIGH SPEED AERATED FLOW IN OPEN CHANNEL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An experiment concerning the sound propaga-tion in aerated open channel flow was designed and conductedin a variable slope chute. The acquisition of sound data wasdone by the hydro-phones installed into the bottom wall of thechute. The data were analyzed and processed by the tape re-corder and a 3562A analyzer. The primary experimetal resultsindicated that the sound speed in aerated flow is varied with the air concentration and highly lower than each of the soundspeed in pure water or air. As released by the derived theoryformula, the minimum sound of 24m/s in aerated flow hap-pened when the air concentration achieved to 50%. This resultshows that the compressibility of high speed aerated flowshould be considered when the air concentration is near to50%. A criterion of compressibility of high speed aerated flowwas also giv. En in this paper.

  19. Effects of intermittent aeration on pollutants removal in subsurface wastewater infiltration system.

    Science.gov (United States)

    Pan, Jing; Fei, Hexin; Song, Siyu; Yuan, Fang; Yu, Long

    2015-09-01

    In this study, the pollutant removal performances in two pilot-scale subsurface wastewater infiltration systems (SWISs) with and without intermittent aeration were investigated. Matrix oxidation reduction potential (ORP) results showed that intermittent aeration well developed aerobic conditions in upper matrix and anoxic or anaerobic conditions in the subsequent sections, which resulted in high NH4(+)-N and TN removal. Moreover, intermittent aeration increased removal rates of COD and TP. Microbial populations and enzyme activities analysis proved that intermittent aeration not only obviously boosted the growth and reproduction of bacteria, fungus, actinomyces, nitrifying bacteria and denitrifying bacteria, but also successfully increased nitrate reductase (NR) and nitrite reductase (NIR) in the depth of 80 and 110 cm. The results suggest that the intermittent aeration could be a widespread research and application strategy for achieving the high removal performance in SWISs.

  20. Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

    Directory of Open Access Journals (Sweden)

    William Z. de Mello

    2013-01-01

    Full Text Available This study investigated the emission of N2O during the sequential aerated (60-min and non-aerated (30-min stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP. N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitrogen load and the per capita emission factor was almost 3 times higher than that suggested by the IPCC for inventories of N2O emission from WWTPs.

  1. 生物活性炭老化对滤池过滤阻力和处理效果的影响%Effect of aged biological activated carbon on the filtration resistance and performance of biological activated carbon filter

    Institute of Scientific and Technical Information of China (English)

    刘璟言; 卢小燕; 尤作亮; 张金松; 郭建宁

    2016-01-01

    Biological activated carbon (BAC) used for about 10years was collected from drinking water treatment plant. The filtration resistance and performance of the aged BAC filter were investigated. The ageing of BAC produced a lot of small BAC particles. The small particles deposited on the surface of the BAC column after backwash and formed a dense filtration layer. The specific resistance of the dense filtration layer was 22 times higher than that of the deep layer of the aged BAC column. Enhanced backwash only decreased the initial filtration resistance and the removal of the dense filtration layer was the most effective method to reduce the filtration resistance. Enhanced backwash had no significant effect on the performance of the aged BAC column. The removal efficiency of the total organic carbon decreased from 24.71% to 7.04% after the removal of the dense filtration layer. However, the removal efficiencies of UV254 and particle count larger than 2µm did not change greatly and the values were nearly the same as those of the control group. There are several methods to increase the life cycle of the aged BAC, including decreasing the backwashing strength and prolonging the filtration cycle.%利用饮用水厂运行10年的生物活性炭(BAC)装填滤柱,研究活性炭老化对滤柱过滤阻力和处理效果的影响.结果表明,活性炭老化会产生大量小粒径颗粒炭,沉积于活性炭池表层的小粒径颗粒炭产生的过滤阻力是滤柱总阻力的主要来源,其比阻约为底层炭的22倍.强化反冲洗仅可降低初始过滤阻力,移除表层细炭是降低活性炭滤池阻力的有效方法.强化反冲洗对滤柱过滤性能无显著影响.移除表层细炭后,老化活性炭滤柱对总有机碳的去除率由24.71%下降至7.04%,而后恢复至移除前的水平.移除表层炭后老化活性炭对UV254和大于2µm颗粒数的去除率与对照组活性炭相似.降低活性炭滤池的反冲强度、延长过滤

  2. [Optimization and comparison of nitrogen and phosphorus removal by different aeration modes in oxidation ditch].

    Science.gov (United States)

    Guo, Chang-Zi; Peng, Dang-Cong; Cheng, Xue-Mei; Wang, Dan

    2012-03-01

    The oxidation ditch operation mode was simulated by sequencing batch reactor (SBR) system with alternate stirring and aeration. The nitrogen and phosphorus removal efficiencies were investigated in two different aeration modes: point aeration and step aeration. Experimental results show that oxygen is dissolved more efficiently in point aeration mode with a longer aerobic region in the same air supply capacity, but dissolved oxygen (DO) utilization efficiency for nitrogen and phosphorus removal is high in step aeration mode. Nitrification abilities of the two modes are equal with ammonia-nitrogen (NH4(+) -N) removal efficiency of 96.68% and 97.03%, respectively. Nitrifier activities are 4.65 and 4.66 mg x (g x h)(-1) respectively. When the ratio of anoxic zones and the aerobic zones were 1, the total nitrogen (TN) removal efficiency of point aeration mode in 2, 4 or 7 partitions was respectively 60.14%, 47.93% and 33.7%. The total phosphorus (TP) removal efficiency was respectively 28.96%, 23.75% and 24.31%. The less the partitions, the higher the nitrogen and phosphorus removal efficiencies, but it is in more favor of TN removal. As for step aeration mode with only one partitioning zone, the TN and TP removal efficiencies are respectively 64.21% and 49.09%, which is better than in point aeration mode, but more conducive to the improvement of TP removal efficiency. Under the condition of sufficient nitrification in step aeration mode, the nitrogen and phosphorus removal is better with the increase of anoxic zone. The removal efficiencies of TN and TP respectively rose to 73.94% and 54.18% when the ratio of anoxic zones and the aerobic zones was increased from 1 : 1 to 1. 8 : 1. As the proportion of anoxic zones was enlarged further, nitrification and operation stability were weakened so as to affect the nitrogen and phosphorus removal efficiencies.

  3. Filter selection using genetic algorithms

    Science.gov (United States)

    Patel, Devesh

    1996-03-01

    Convolution operators act as matched filters for certain types of variations found in images and have been extensively used in the analysis of images. However, filtering through a bank of N filters generates N filtered images, consequently increasing the amount of data considerably. Moreover, not all these filters have the same discriminatory capabilities for the individual images, thus making the task of any classifier difficult. In this paper, we use genetic algorithms to select a subset of relevant filters. Genetic algorithms represent a class of adaptive search techniques where the processes are similar to natural selection of biological evolution. The steady state model (GENITOR) has been used in this paper. The reduction of filters improves the performance of the classifier (which in this paper is the multi-layer perceptron neural network) and furthermore reduces the computational requirement. In this study we use the Laws filters which were proposed for the analysis of texture images. Our aim is to recognize the different textures on the images using the reduced filter set.

  4. Remoção de diclofenaco, ibuprofeno, naproxeno e paracetamol em filtro ecológico seguido por filtro de carvão granular biologicamente ativado Removal of diclofenac, ibuprofen, naproxen, and paracetamol in ecological filter followed by granular carbon filter biologically active

    Directory of Open Access Journals (Sweden)

    Caroline Moço Erba

    2012-06-01

    Full Text Available O filtro ecológico representa uma promissora tecnologia de tratamento, em razão desta não necessitar da aplicação de produtos químicos, além de sua constatada eficiência. Nele, estabelece-se entre os seres vivos a relação de cadeia alimentar. Inicialmente uma matriz aquosa foi acrescida de quatro fármacos (diclofenaco, naproxeno, ibuprofeno e paracetamol e posteriormente analisada por cromatografia líquida de alta eficiência para avaliar a remoção desses compostos pelo filtro ecológico seguido pelo filtro de carvão granular biologicamente ativado. Parâmetros, entre eles turbidez, coliformes totais e termotolerantes, cor aparente e cor verdadeira, foram mensurados para verificar a eficiência dos filtros. Houve remoção de 97,43% do diclofenaco, 85,03% do ibuprofeno: 94,11% do naproxeno e 84,07% do paracetamol.The ecological filter represents a promising treatment technology, because this doesn't require the application of chemicals and is efficient. In it, is between living beings the relationship of the food chain. Initially an aqueous matrix was added to four drugs (diclofenac, naproxen, ibuprofen and paracetamol, and subsequently analyzed by high performance liquid chromatography to evaluate the removal of these compounds by ecological filter followed by granular activated carbon filter biologically active. The pharmacological compounds and parameters such as turbity, total and fecal coliforms, apparent color and true color were measured to evaluate the effectiveness of filters. There was removal of the drugs applied and the parameters measured. The percentages of removal were 97,43% of diclofenaco,85,03% of ibuprofen, 94,11% of naproxen and 84,07% of paracetamol.

  5. DOMESTIC WASTEWATER PURIFICATION IN UPFLOW BIOFILM SYSTEM WITH DIFFUSED AERATION

    Directory of Open Access Journals (Sweden)

    A.Mesdaghinia

    1984-08-01

    Full Text Available The objective of this research was to conduct a bench scale study of fixed activated sludge treating domestic sewage. Two different units employing diffused aeration with plastic and aluminum media were studied in four separate phases. Data indicated that the system could produce a high quality effluent without any requirements for sludge recycling through the system. Suspended solids concentrations of 3-6 mg/1, BOD5 concentrations of 4-12 mg/1 and COD concentrations of 35-45 mg/1 were found in the effluent with wastewater retentions ranging from 3-15 hours, whereas an indication of nitrification was observed in higher detention periods. As far as the type of media was concerned, the plastic and aluminum media did not differ significantly once the microbes had grown on the media.

  6. Thermal conductivity of newspaper sandwiched aerated lightweight concrete panel

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Soon-Ching; Low, Kaw-Sai [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur, Wilayah Persekutuan (Malaysia)

    2010-12-15

    Investigation on the thermal conductivity of newspaper sandwiched aerated lightweight concrete (ALC) panels is the main purpose of this study. Various densities of ALC panels ranging from 1700, 1400 and 1100 kg/m{sup 3} with three different aerial intensities of newspaper sandwiched were produced. Investigation was limited to the effect of aerial intensity of newspaper sandwiched and the effect of density of ALC on thermal conductivity. It is found that the thermal conductivity of newspaper sandwiched ALC panels reduced remarkably compared to control ALC panels. The reduction was recorded at 18.0%, 21.8% and 20.7% correspond to densities of 1700, 1400 and 1100 kg/m{sup 3} with just a mere 0.05 g/cm{sup 2} aerial intensity of newspaper sandwiched. Newspaper sandwiched has a significant impact on the performance of thermal conductivity of ALC panels based on regression analysis. (author)

  7. Nitrogen and phosphorus removal under intermittent aeration conditions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A practice wastewater treatment plant was operated usingintermittent aeration activated sludge process to enhancebiological nitrogen and phosphorus removal. When the influentconcentrations of CODCr, BOD5, TN, TP, NH3-N, TKN, and SS varied ina range of 207.5-1640 mg/L, 61.8-637 mg/L, 28.5-75.6 mg/L, 4.38-20.2 mg/L, 13.6-31.9 mg/L, 28.5-75.6 mg/L, and 111-1208 mg/L, theeffluent means were less than 50 mg/L, 20 mg/L, 5 mg/L, 1.0 mg/L,5 mg/L, 10 mg/L, and 20 mg/L, respectively. Based on a long time ofoperating results, this process is very suitable for nutrientbiological removal for treating the municipal wastewater thosewater characteristics are similar as that of the Songjiang Municipal Waste water Treatment plant(SJMWTP).

  8. Structure, composition, and strength of nitrifying membrane-aerated biofilms

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Smets, Barth F.

    2014-01-01

    Membrane-aerated biofilm reactors (MABRs) are a novel technology based on the growth of biofilms on oxygen-permeable membranes. Hereby, MABRs combine all the advantages of biofilm growth with a more flexible and efficient control of the oxygen load. In the present work, flow cell operation...... to achieve full nitrification revealed a significantly different structure of nitrifying MABR biofilms with respect to its co-diffusion counterparts reported in the literature (up to now assumed to have similar properties). Different levels of shear stress and oxygen loadings during MABR operation also...... affected these biofilm parameters. Furthermore, reactor operation at higher oxygen loads resulted in an increase of the biofilm cohesiveness, which depended on the EPS mass in the biofilms and the type of stress applied (more cohesive against normal than shear stresses). The EPS in the strongest biofilms...

  9. Aeration-Controlled Formation of Acid in Heterolactic Fermentations

    DEFF Research Database (Denmark)

    Adler-Nissen, Jens

    1994-01-01

    Controlled aeration of Leuconostoc mesenteroides was studied as a possible mechanism for control of the formation of acetic acid, a metabolite of major influence on the taste of lactic fermented foods. Fermentations were carried out in small scale in a medium in which growth was limited...... by the buffer capacity only. Ethanol and acetic acid formed during the fermentation were analyzed by rapid head space gas chromatography, and the ratio of the molar concentrations of these two volatiles quantitatively predicted the balance between the formation of acetic acid and lactic acid. The oxygen...... fermentation processes should be analyzed as fed-batch fermentations with oxygen as the limiting substrate. Addition of fructose in limited amounts leads to the formation of one half mole of acetic acid for each mole fructose, thus offering an alternative mechanism for controlling acetic acid formation....

  10. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, D., E-mail: daniele.ferretti@unipr.it [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Michelini, E. [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, P.co Area delle Scienze 181/A, 43124 Parma (Italy); Rosati, G. [Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)

    2015-01-15

    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM.

  11. [Effects of substrate-aeration cultivation pattern on tomato growth].

    Science.gov (United States)

    Zhao, Xu; Li, Tian-Lai; Sun, Zhou-Ping

    2010-01-01

    Aeroponics can increase the fruit yield of tomato plant, but its cost is very high. In this paper, tomato seedlings were planted with three cultures, i. e., whole perlite culture (CK), perlite-aeration culture (T1), and aeroponics (T2), and a comparative study was made on the seedlings growth. Compared with CK, T1 improved the gas environment in root zone significantly, with the CO2 and O2 concentrations in root zone being 0.2 and 1.17 times higher, and increased the plant height and stem diameter after 60 days of transplanting by 5.1% and 8.4%, respectively. The plant net photosynthetic rate of T1 was significantly higher than that of CK, with the maximum value after transplanting 45 days increased by 13%. T1 also increased the root activity and ion absorbing ability significantly, with the root activity after transplanting 45 days being 1.23 times of CK, and the root K, Ca, and Mg contents after transplanting 60 days increased by 31%, 37%, and 27%, respectively. The fruit yield of T1 was 1.16 times of CK. No significant differences in these indices were observed between T1 and T2, and less difference in the fruit soluble sugar and organic acid contents as well as the sugar-acid ratio was found among CK, T1, and T2. It was suggested that perlite-aeration cultivation pattern was an easy and feasible way to markedly improve the fruit yield of tomato plant.

  12. Effects of loading rate and aeration on nitrogen removal and N2O emissions in intermittently aerated sequencing batch reactors treating slaughterhouse wastewater at 11 °C.

    Science.gov (United States)

    Pan, Min; Hu, Zhenhu; Liu, Rui; Zhan, Xinmin

    2015-04-01

    This study aimed to find optimal operation conditions for nitrogen removal from high strength slaughterhouse wastewater at 11 °C using the intermittently aerated sequencing batch reactors (IASBRs) so as to provide an engineering control strategy for the IASBR technology. Two operational parameters were examined: (1) loading rates and (2) aeration rates. Both the two parameters affected variation of DO concentrations in the IASBR operation cycles. It was found that to achieve efficient nitrogen removal via partial nitrification-denitrification (PND), "DO elbow" point must appear at the end of the last aeration period. There was a correlation between the ammonium oxidizing bacteria (AOB)/nitrite oxidizing bacteria (NOB) ratio and the average DO concentrations in the last aeration periods; when the average DO concentrations in the last aeration periods were lower than 4.86 mg/L, AOB became the dominant nitrifier population, which benefited nitrogen removal via PND. Both the nitrogen loading rate and the aeration rate influenced the population sizes of AOB and NOB. To accomplish efficient nitrogen removal via PND, the optimum aeration rate (A, L air/min) applied can be predicted according to the average organic loading rates based on mathematical equations developed in this study. The research shows that the amount of N2O generation in the aeration period was reduced with increasing the aeration rate; however, the highest N2O generation in the non-aeration period was observed at the optimum aeration rates.

  13. Influence of aeration intensity on mature aerobic granules in sequencing batch reactor.

    Science.gov (United States)

    Gao, Da-Wen; Liu, Lin; Liang, Hong

    2013-05-01

    Aeration intensity is well known as an important factor in the formation of aerobic granules. In this research, two identical lab-scale sequencing batch reactors with aeration intensity of 0.8 (R1) and 0.2 m(3)/h (R2) were operated to investigate the characteristics and kinetics of matured aerobic granules. Results showed that both aeration intensity conditions induced granulation, but they showed different effects on the characteristics of aerobic granules. Compared with the low aeration intensity (R2), the aerobic granules under the higher aeration intensity (R1) had better physical characteristics and settling ability. However, the observed biomass yield (Y obs) in R1 [0.673 kg mixed liquor volatile suspended solids (MLVSS)/kg chemical oxygen demand (COD)] was lower than R2 (0.749 kg MLVSS/kg COD). In addition, the maximum specific COD removal rates (q max) and apparent half rate constant (K) of mature aerobic granular sludge under the two aeration intensities were at a similar level. Therefore, the matured aerobic granule system does not require to be operated in a higher aeration intensity, which will reduce the energy consumption.

  14. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    Science.gov (United States)

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.

  15. Generalised Filtering

    Directory of Open Access Journals (Sweden)

    Karl Friston

    2010-01-01

    Full Text Available We describe a Bayesian filtering scheme for nonlinear state-space models in continuous time. This scheme is called Generalised Filtering and furnishes posterior (conditional densities on hidden states and unknown parameters generating observed data. Crucially, the scheme operates online, assimilating data to optimize the conditional density on time-varying states and time-invariant parameters. In contrast to Kalman and Particle smoothing, Generalised Filtering does not require a backwards pass. In contrast to variational schemes, it does not assume conditional independence between the states and parameters. Generalised Filtering optimises the conditional density with respect to a free-energy bound on the model's log-evidence. This optimisation uses the generalised motion of hidden states and parameters, under the prior assumption that the motion of the parameters is small. We describe the scheme, present comparative evaluations with a fixed-form variational version, and conclude with an illustrative application to a nonlinear state-space model of brain imaging time-series.

  16. Notch filter

    Science.gov (United States)

    Shelton, G. B. (Inventor)

    1977-01-01

    A notch filter for the selective attenuation of a narrow band of frequencies out of a larger band was developed. A helical resonator is connected to an input circuit and an output circuit through discrete and equal capacitors, and a resistor is connected between the input and the output circuits.

  17. Marine Biology

    Science.gov (United States)

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  18. The role of loading rate, backwashing, water and air velocities in an up-flow nitrifying tertiary filter.

    Science.gov (United States)

    Vigne, Emmanuelle; Choubert, Jean-Marc; Canler, Jean-Pierre; Heduit, Alain; Sørensen, Kim Helleshøj; Lessard, Paul

    2011-01-01

    The vertical distribution of nitrification performances in an up-flow biological aerated filter operated at tertiary nitrification stage is evaluated in this paper. Experimental data were collected from a semi-industrial pilot-plant under various operating conditions. The actual and the maximum nitrification rates were measured at different levels inside the up-flow biofilter. A nitrogen loading rate higher than 1.0 kg NH4-Nm(-3)_mediad(-1) is necessary to obtain nitrification activity over all the height of the biofilter. The increase in water and air velocities from 6 to 10 m h(-1) and 10 to 20 m h(-1) has increased the nitrification rate by 80% and 20% respectively. Backwashing decreases the maximum nitrification rate in the media by only 3-14%. The nitrification rate measured at a level of 0.5 m above the bottom of the filter is four times higher than the applied daily average volumetric nitrogen loading rate up to 1.5 kg NH4-N m(-3)_mediad(-1). Finally, it is shown that 58% of the available nitrification activity is mobilized in steady-state conditions while up to 100% is used under inflow-rate increase.

  19. EFFECT OF HYDRAULIC AND GEOMETRICAL PROPERTIES ON STEPPED CASCADE AERATION SYSTEM

    Directory of Open Access Journals (Sweden)

    VEDHACHALAM RATHINAKUMAR

    2017-03-01

    Full Text Available Stepped cascade aeration system is commonly used to aerate the water and wastewater to increase the dissolved oxygen during pre and post treatment process. In the present research, experiments were conducted to evaluate the performance of a rectangular Cascade Aeration System with varying flow rates, risers and tread by maintaining constant width of the channel using water collected from reverse osmosis plant. The experiments were carried out with four different risers such as 0.15 m, 0.18 m, 0.225 m and 0.30 m. Each rise was investigated with five different tread of 0.60 m, 0.55 m, 0.50 m, 0.45 m and 0.40 m. Comprehensive experimental investigations were carried out for different hydraulic loading rates of 0.005 to 0.035 m3/s/m2. Results obtained from the experiments reveals that increasing dimensionless discharges promotes more aeration, attains a maximum up to dimensionless discharge= 2.22 and beyond this there was a significant decrease in aeration. In addition, the increased in number of steps significantly enhances air entertainment and surface fall rate in the Stepped Cascade Aeration System. A regression equation was derived by keeping aeration efficiency as response with dimensionless discharge and oxygen saturation concentration as influencing parameters. The dimension less discharge is a function of critical depth of the rectangular channel and step height, whereas oxygen saturation concentration represents the ratio of oxygen deficit and oxygen saturation concentration. Based on the experimental results, the optimum design and/or results such as number of steps (12 numbers and hydraulic loading rate (0.025 m3/s/m2 with fixed tread width of 0.6 m were identified to achieve maximum aeration rate (0.5-0.60 in Aeration system.

  20. Treatment Wetland Aeration without Electricity? Lessons Learned from the First Experiment Using a Wind-Driven Air Pump

    Directory of Open Access Journals (Sweden)

    Johannes Boog

    2016-11-01

    Full Text Available Aerated treatment wetlands have become an increasingly recognized technology for treating wastewaters from domestic and various industrial origins. To date, treatment wetland aeration is provided by air pumps which require access to the energy grid. The requirement for electricity increases the ecological footprint of an aerated wetland and limits the application of this technology to areas with centralized electrical infrastructure. Wind power offers another possibility as a driver for wetland aeration, but its use for this purpose has not yet been investigated. This paper reports the first experimental trial using a simple wind-driven air pump to replace the conventional electric air blowers of an aerated horizontal subsurface flow wetland. The wind-driven air pump was connected to a two-year old horizontal flow aerated wetland which had been in continuous (24 h aeration since startup. The wind-driven aeration system functioned, however it was not specifically adapted to wetland aeration. As a result, treatment performance decreased compared to prior continuous aeration. Inconsistent wind speed at the site may have resulted in insufficient pressure within the aeration manifold, resulting in insufficient air supply to the wetland. This paper discusses the lessons learned during the experiment.

  1. THREE-DIMENSIONAL NUMERICAL SIMULATION OF AERATED FLOWS DOWNSTREAM SUDDEN FALL AERATOR EXPANSION-IN A TUNNEL

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-min; CHEN Jian-gang; XU Wei-lin; WANG Yu-rong; LI Gui-ji

    2011-01-01

    Air entrainment is known to be one of efficient and inexpensive methods to prevent cavitation damages in hydropower projects.The shape of sudden expansion-fall is used as a common device for mitigating cavitation erosions.The complex flow patterns with cavitation are numerically simulated by using the realizable k-ε turbulence model and the air-water mixture model.The calculated results are compared well with the experimental results as well as those obtained with the k -ε turbulence model with the Volume Of Fluid (VOF) Model.The calculated results agree well with the experimental data for the aeration cavity and wall pressure.Moreover, the air concentration near sidewall is simulated by a mixture model.It is found that the mixture turbulence model is superior to the VOF turbulence model.

  2. Aeration remediation of a polluted waterway increases near-surface coarse and culturable microbial aerosols.

    Science.gov (United States)

    Dueker, M Elias; O'Mullan, Gregory D

    2014-04-15

    Aeration remediation is currently used in polluted urban waterways to increase oxygen levels in the water column. Recent studies have provided increasing evidence that the bursting of bubbles at water surfaces introduced by aeration, or other surface disturbances, can transfer viable bacteria to the air. In heavily sewage-polluted waterways these water-originated bacterial aerosols may pose as a health risk to recreators in small boats or residents inhabiting the shoreline. Nonetheless, few studies have explored aerosols above active aeration remediation projects in waterways or investigated how bacterial aerosols change with vertical distance from aeration activities. This study, conducted at the Newtown Creek superfund site in Brooklyn, NY, USA, measured coarse aerosol particles and culturable bacteria in near-surface air above waters undergoing aeration remediation. Regardless of aeration operation culturable bacterial fallout was greater near-surface (0.6m above water) than previously-reported measurements made at 2.5m. Molecular analysis of the 16S rRNA gene sequences from isolated bacteria demonstrates that water and air shared a large number of bacterial genera and that the genera present in the near-surface aerosols (0.6m) contained water-associated Vibrio and Caulobacter, which were not present at 2.5m, despite the smaller sequence library size from the near-surface. Also, the near-surface microbial assemblage had significantly greater association with sequences detected previously in aquatic environments compared to the 2.5m library. We found compelling evidence that aeration activity contributed to this vertical gradient in bacterial aerosol concentrations and identity. Similar to results from 2.5m, concentrations of near-surface respirable coarse aerosols (aeration was occurring. Culturable bacterial aerosol fallout was also greater near-surface when the aerator was on compared to simultaneous measurements made at 2.5m. Furthermore, when the aerator was

  3. NUMERICAL SIMULATION OF 3-D AERATED JET BEHIND FLIP BUCKET OF OVERFLOW DAM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Aerated jet,such as the jet flow behind the flip bucket of an overflow dam, widely exists in hydraulic engineering. Up to now the model test and prototype observation have been two main methods of studying the aerated jet for a special hydraulic project. In this paper, a three-dimensional mathematical model for the aerated jet was established. It seems that the suggested model has high predictive power by comparison with the results of model tests and prototype observations, which is very useful in the study of energy dissipation and jet flow atomization.

  4. AN INVESTIGATION OF FLOW CHARACTERISTIC OF AERATED DRAG REDUCTION IN TUBE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Under the aerated conditions of wall and top intube, the turbulent flow in the tube was measured by usingLDA. The turbulent structure of the flow field and the mech-anism of aerating drag reduction in the tube were discussed. It is shown that the energy dissipations of turbulence flow andmean flow will reduce and the flow velocity (or flow rate) willincrease by injecting mini-bubbles to the wall or top of tube,namely the effect of aerating drag reduction is attained.

  5. Aeration effect on Spirulina platensis growth and γ-linolenic acid production

    OpenAIRE

    Srinivasa Reddy Ronda; Chandra Sekhar Bokka; Chandrika Ketineni; Binod Rijal; Prasada Rao Allu

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2– 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g-1 dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vv...

  6. Improving microalgal growth with reduced diameters of aeration bubbles and enhanced mass transfer of solution in an oscillating flow field.

    Science.gov (United States)

    Yang, Zongbo; Cheng, Jun; Lin, Richen; Zhou, Junhu; Cen, Kefa

    2016-07-01

    A novel oscillating gas aerator combined with an oscillating baffle was proposed to generate smaller aeration bubbles and enhance solution mass transfer, which can improve microalgal growth in a raceway pond. A high-speed photography system (HSP) was used to measure bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure mass-transfer coefficient and mixing time. Bubble diameter and generation time decreased with decreased aeration gas rate, decreased orifice diameter, and increased water velocity in the oscillating gas aerator. The optimized oscillating gas aerator decreased bubble diameter and generation time by 25% and 58%, respectively, compared with a horizontal tubular gas aerator. Using an oscillating gas aerator and an oscillating baffle in a raceway pond increased the solution mass-transfer coefficient by 15% and decreased mixing time by 32%; consequently, microalgal biomass yield increased by 19%.

  7. Enhanced long-term organics and nitrogen removal and associated microbial community in intermittently aerated subsurface flow constructed wetlands.

    Science.gov (United States)

    Fan, Jinlin; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Wu, Haiming

    2016-08-01

    The long-term enhanced removal efficiency of organics and nitrogen in subsurface flow constructed wetlands (SSF CWs) with and without intermittent aeration for decentralized domestic wastewater was evaluated, and the function of intermittent aeration on microbial community was also investigated in this study. The high and long-term 95.6% COD, 96.1% NH4(+)-N and 85.8% TN removal efficiencies were achieved in experimental intermittently aerated SSF CW compared with non-aerated SSF CW. Aerated SSF CWs also exhibited the excellent removal performance when comparatively comparing with other strategies and techniques applied in CWs. In addition, fluorescence in situ hybridization (FISH) analysis revealed that associated microbial abundance significantly increased owing to intermittent aeration. These results indicated intermittent aeration CWs might be an effective and sustainable strategy for wastewater treatment in rural areas, but require further full-scale investigation in future.

  8. UASB/flash aeration enable complete treatment of municipal wastewater for reuse.

    Science.gov (United States)

    Khan, Abid Ali; Gaur, Rubia Zahid; Lew, Beni; Diamantis, Vasileios; Mehrotra, Indu; Kazmi, A A

    2012-08-01

    A simple, efficient and cost-effective method for municipal wastewater treatment is examined in this paper. The municipal wastewater is treated using an upflow anaerobic sludge bed (UASB) reactor followed by flash aeration (FA) as the post-treatment, without implementing aerobic biological processes. The UASB reactor was operated without recycle, at hydraulic retention time (HRT) of 8 h and achieved consistent removal of BOD, COD and TSS of 60-70% for more than 12 months. The effect of FA on UASB effluent post-treatment was studied at different HRT (15, 30 and 60 min) and dissolved oxygen (DO) concentrations (low DO = 1-2 mg/L and high DO = 5-6 mg/L). The optimum conditions for BOD, COD and sulfide removal were 30-60 min HRT and high DO concentration inside the FA tank. The final effluent after clarification was characterized by BOD and COD values of 28-35 and 50-58 mg/L, respectively. Sulfides were removed by more than 80%, but the fecal coliform only by ~2 log. The UASB followed by FA is a simple and efficient process for municipal wastewater treatment, except for fecal coliform, enabling water and nutrients recycling to agriculture.

  9. Combination and Application on A/O Bio-chemical Pool and BAF Biological Filter%A/O生化池和BAF生物滤池的组合应用

    Institute of Scientific and Technical Information of China (English)

    段进元

    2012-01-01

      The paper presents the application principle and its result on two-grade combination of bio-chemistry of A/O bio-chemical pool and BAF biological filter, makes analysis on inlet and outlet water quality of two-grade bio-chemistry and explains the problems existed in system operation.%  较为全面地介绍了A/O生化池和BAF生物滤池两级生化合并的应用原理和效果,对两级生化的进出水水质进行了分析,并对系统运行中存在的问题进行了阐述。

  10. Equalization characteristics of an upflow sludge blanket-aerated biofilter (USB-AF) system.

    Science.gov (United States)

    Jun, H B; Park, S M; Park, J K; Lee, S H

    2005-01-01

    Equalization characteristics of the upflow sludge blanket-aerated bio-filter (USB-AF) were investigated with the fluctuated raw domestic sewage. Recycle of nitrified effluent from AF to USB triggered the equalization characteristics of the sludge blanket on both soluble and particulate organic matter. Increment of EPS in sludge blanket by nitrate recycle was detected and removal of turbidity and particulates increased at higher recycle ratios by bio-flocculation. Increased TCOD removal in the USB was due to both denitrification of recycled nitrate and entrapment of the particulate organic matter in sludge blanket. Capture of both soluble and particulate organic matter increased sludge blanket layer in the USB, which improved the reactor performances and reduced the organic load on the subsequent AF. Overall TCOD and SS removal efficiencies were about 98% and 96%, respectively in the USB-AF system. Turbidity in the USB effluent was about 44, 20 and 5.5 NTU, at recycle ratios of 0, 100 and 200%, respectively. Particle counts in the range 2-4 microm in the USB effluent were higher than those in influent without nitrate recycle, while particle counts in the range of 0.5-15 microm in the USB effluent decreased 70% at recycle ratio of 200%. The major constituent of EPS extracted from anaerobic sludge was protein and total EPS increased from 109.1 to 165.7 mg/g-VSS with nitrate recycle of 100%. Removal efficiency and concentration of T-N in the UBS-AF effluent was over 70% and below 16 mg/L, respectively.

  11. Hydrodynamics of Three Biological Trickling Beds with Inert Filters%三种惰性填料生物滴滤床的流体力学性能

    Institute of Scientific and Technical Information of China (English)

    周超; 王芙蓉; 韩帅; 卢宏旭; 丁文明

    2016-01-01

    Using natural zeolite, expanded vermiculite and biological ceramsite as biological trickling bed fillers, in some running conditions such as dry and wet, spray amount, microbial growth, experiment of bed pressure drop vs gas flowrate data was carried out, and the pressure drop curve was obtained. Results showed that in various conditions biological ceramsite showed the best hydrodynamics performance. For the fragmented packing such as natural zeolite and expanded vermiculite, wetting can decrease the pressure drop loss, but spray volume would increase the pressure drop loss. Biofilm growth increased bed pressure drop loss, but for biological ceramsite packed bed the pressure drop increase was not significant.%对天然沸石、膨胀蛭石、生物陶粒等三种生物滴滤床惰性填料,进行了干燥与湿润、喷淋量、微生物生长等不同条件下,气体流量与床层压降数据测量,得到了影响条件下的压降曲线。结果分析显示,生物陶粒在各种条件下均表现出较好的流体力学性能;对天然沸石及膨胀蛭石类碎片状填料,润湿可减小压降损失,喷淋量过大会增大压降损失;生物膜生长增加生物滤床的压降损失,但对生物陶粒填料床,压降增加不显著。

  12. Effects of impeller speed and aeration rate on flotation performance of sulphide ore

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of aeration rate and impeller speed on the concentrate sulfur grade and recovery for batch flotation of a complex sulphide ore were investigated. The relationships between the water recovery and solid entrainment were discussed. It is found that the solid entrainment is linearly related to the water recovery regardless of aeration rate and impeller speed, and the higher sulfur recovery at the aeration rate of 2 and 4 L/min for the impeller speed of 1 500 r/min is considered to be the contribution of true flotation. Finally, the sulfur recovery flux is correlated with the bubble surface area flux based on the froth image at the different aeration rates and impeller speeds.

  13. The effect of aeration on the biotransformation of lignocellulosic wastes by white-rot fungi.

    Science.gov (United States)

    López, M J; Elorrieta, M A; Vargas-García, M C; Suárez-Estrella, F; Moreno, J

    2002-01-01

    The mineralisation and the humification of organic matter (OM) in sterile horticultural plant wastes inoculated with Coriolus versicolor or Phanerochaete flavido-alba was investigated under different aeration rates in order to determine their efficacy as potential inoculants for composting. The change in elemental composition, lignin content and OM fractions was analysed during a 90-day incubation. Both fungi degraded 30% of lignin at low aeration rates. Different aeration rates led to significant changes in OM mineralisation induced by C. versicolor, but did not have noticeable effect on P. flavido-alba activity. The mineralisation was more effectively carried out by P. flavido-alba than by C. versicolor. Lignin degradation and the linked humification process were equally achieved by the two fungi and were enhanced in aerated conditions. The fungi analysed may facilitate the composting of lignocellulosic wastes by means of an increase in substrate bioavailability and OM humification.

  14. Effects of Aerated Irrigation on Leaf Senescence at Late Growth Stage and Grain Yield of Rice

    Institute of Scientific and Technical Information of China (English)

    ZHU Lian-feng; Yu Sheng-miao; JIN Qian-yu

    2012-01-01

    With the japonica inbred cultivar Xiushui 09,indica hybrid combinations Guodao 6 and Liangyoupeijiu as materials,field experiments were conducted in 2007 and 2008 to study the effects of aerated irrigation on leaf senescence at late growth stage and grain yield of rice.The dissolved oxygen concentration of aerated water evidently increased and decreased at a slow rate.The soil oxidation-reduction potential under aerated irrigation treatment was significantly higher than that of the CK,contributing to significant increases in effective panicles,seed setting rate and grain yield.In addition,the aerated irrigation improved root function,increased superoxide dismutase activity and decreased malondialdehyde content in flag leaves at post-flowering,which delayed leaf senescence process,prolonged leaf functional activity and led to enhanced grain filling.

  15. Integral Parameters for Characterizing Water, Energy, and Aeration Properties of Soilless Plant Growth Media

    DEFF Research Database (Denmark)

    Deepagoda Thuduwe Kankanamge Kelum, Chamindu; Lopez, Jose Choc Chen; Møldrup, Per

    2013-01-01

    systems are regaining increased worldwide attention. The optimal control of water availability and aeration is an essential prerequisite to successfully operate plant growth systems with soilless substrates such as aggregated foamed glass, perlite, rockwool, coconut coir, or mixtures thereof. While...

  16. SONIC SPEED AND SHOCK WAVE IN HIGH VELOCITY AERATED FLOWS FROM HIGH HEAD DISCHARGE STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    Dong Zhi-yong

    2003-01-01

    The compressible characteristics in aerated flows at the high velocity of about 50m/s were analyzed. Based on the theory of compressible the relations between the sonic speed and shock wave in high-velocity aerated flow were theoretically deduced. And comparisons with measured data were made. The theoretical and experimental results show the sonic speed in aerated flow is merely of the order of several-dozen meters per second, and its minimum value is only 20m/s, which is far much less than that in water or air alone. So high subsonic flow, supersonic flow and transonic flow as well as compression wave, shock wave and expansion wave similarly to aerodnamics may be produced in high velocity aerated flow at the speed of the order of 50m/s. Hence the influences of these compressible characteristics on high head discharge structures can not be neglected, especially on super high dams over 200m high.

  17. Fluctuant characteristics of two-phase flow behind a bottom aerator

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Experimental observations show that the random process of two-phase flow behind an aerator is an ergodic process and its amplitude distribution is similar to a normal distribution. The maximum pressure fluctuation is at the re-attachment point where the jet-trajectory flow over the aerator re-attaches to the bottom of the channel, and its amplitude is 2—3 times larger than when there is no aerator. There is a dominant frequency of 1.24 Hz in the model, but the coherence in the frequency domain is not obvious for other frequencies beside the dominant frequency. There is a large vortex at the re-attachment point behind the aerator but correlation among the measurement points is not obvious in the time domain.

  18. Evaluation of the corrosion resistance of AISI 316 stainless steel filters

    Directory of Open Access Journals (Sweden)

    Luzinete Pereira Barbosa

    2005-06-01

    Full Text Available In this investigation, the corrosion resistance of AISI 316 SS filters prepared with powders in the size ranges 74-44 µm and 210-105 µm and compacted with pressures of 300 MPa and 400 MPa has been evaluated in naturally aerated 0.5 M H2SO4 solution at 25 °C. Weight loss of filters manufactured with compacting pressure of 400 MPa were significantly higher than that of filters compacted at 300 MPa. The filter compacted at 400 MPa had higher carbon and nitrogen contents compared to those compacted at 300 MPa. The former also had chromium rich precipitates and oxides in the grain boundaries. The pores in filters compacted at 400 MPa were smaller than in filters compacted at 300 MPa. Smaller pores favor the formation of concentration cells and consequently, increased crevice corrosion.

  19. Removal of arsenic and iron removal from drinking water using coagulation and biological treatment.

    Science.gov (United States)

    Pramanik, Biplob Kumar; Pramanik, Sagor Kumar; Suja, Fatihah

    2016-02-01

    Effects of biological activated carbon (BAC), biological aerated filter (BAF), alum coagulation and Moringa oleifera coagulation were investigated to remove iron and arsenic contaminants from drinking water. At an initial dose of 5 mg/L, the removal efficiency for arsenic and iron was 63% and 58% respectively using alum, and 47% and 41% respectively using Moringa oleifera. The removal of both contaminants increased with the increase in coagulant dose and decrease in pH. Biological processes were more effective in removing these contaminants than coagulation. Compared to BAF, BAC gave greater removal of both arsenic and iron, removing 85% and 74%, respectively. Longer contact time for both processes could reduce the greater concentration of arsenic and iron contaminants. The addition of coagulation (at 5 mg/L dosage) and a biological process (with 15 or 60 min contact time) could significantly increase removal efficiency, and the maximum removal was observed for the combination of alum and BAC treatment (60 min contact time), with 100% and 98.56% for arsenic and iron respectively. The reduction efficiency of arsenic and iron reduced with the increase in the concentration of dissolved organics in the feedwater due to the adsorption competition between organic molecules and heavy metals.

  20. Nitrate-removal activity of a biofilm attached to a perlite carrier under continuous aeration conditions.

    Science.gov (United States)

    Yamashita, Takahiro; Yokoyama, Hiroshi; Kanafusa, Sumiyo; Ogino, Akifumi; Ishida, Mitsuyoshi; Osada, Takashi; Tanaka, Yasuo

    2011-01-01

    The nitrate-removal activity of a biofilm attached to a perlite carrier from an aerobic bioreactor used for treating dairy farm wastewater was examined by batch experiments under continuous aeration conditions. Despite aeration, the biofilm removed nitrate at a rate of 114.4 mg-N/kg-perlite/h from wastewater containing cow milk and manure. In a clone library analysis of the biofilm, bacteria showing high similarity to the denitrifying bacteria Thauera spp. were detected.

  1. Aerated lagooning of agro-industrial wastewater: depuration performance and energy requirements

    Directory of Open Access Journals (Sweden)

    Serafina Andiloro

    2013-09-01

    Full Text Available Intensive depuration plants have often shown low reliability and economic sustainability, when utilised for agro-industrial wastewater treatment, due to the particular wastewater properties: high organic load and essential oil concentrations, acidity, nutrient scarcity and qualitative-quantitative variability of effluents. Aerated lagooning systems represent a suitable alternative, because they are able to assure good reliability and low energy requirements, avoiding the drawbacks shown by the intensive depuration plants. In order to optimize performance of the lagooning systems, particularly in terms of energy requirements, depuration processes of aerobic-anaerobic aerated lagoons were investigated, both at full- and laboratory-scale. Citrus processing wastewater were subject to bubble aeration with low flow rates and limited time; the removal rate of organic load was evaluated and energy requirements of different depuration schemes were compared. The experimental investigations in full-scale aerated lagoons showed a low energy supply (0.21-0.59 kWh per kg of COD (Chemical Oxygen Demand removed with an average value of 0.45 kWh kgCOD –1, an adequate equalisation capability and constantly good depurative performance also with high concentrations of essential oil (500-1000 ppm. The experimental investigations in lab-scale aerated tanks under controlled conditions indicated the possibility of decreasing energy requirements (down to 0.16 kWh kgCOD –1 by reducing aeration power (down to 0.6 W m–3 and limiting aeration time to night 12 hours only, when energy price is lower. In spite of the low aeration, the COD removal rates were on the average six-fold higher compared to the anaerobic tank. Other outcomes indicated an ability of the spontaneous microflora to adapt to high concentrations of essential oils, which however did not provide an increase of the removal rate of the organic load in the experimented scheme.

  2. CRYSTAL FILTER TEST SET

    Science.gov (United States)

    CRYSTAL FILTERS, *HIGH FREQUENCY, *RADIOFREQUENCY FILTERS, AMPLIFIERS, ELECTRIC POTENTIAL, FREQUENCY, IMPEDANCE MATCHING , INSTRUMENTATION, RADIOFREQUENCY, RADIOFREQUENCY AMPLIFIERS, TEST EQUIPMENT, TEST METHODS

  3. Aeration effect on Spirulina platensis growth and γ-Linolenic acid production

    Science.gov (United States)

    Ronda, Srinivasa Reddy; Bokka, Chandra Sekhar; Ketineni, Chandrika; Rijal, Binod; Allu, Prasada Rao

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2– 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g-1 dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6–9.5 mg· g-1 dry cell weight). In addition, the total fatty acid (TFA) content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model. PMID:24031799

  4. Aeration effect on Spirulina platensis growth and γ-linolenic acid production

    Directory of Open Access Journals (Sweden)

    Srinivasa Reddy Ronda

    2012-03-01

    Full Text Available The influence of aeration on algal growth and gamma-linolenic acid (GLA production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2-2.5 vvm. Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g-1 dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6-9.5 mg· g-1 dry cell weight. In addition, the total fatty acid (TFA content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model.

  5. Aeration effect on Spirulina platensis growth and γ-Linolenic acid production.

    Science.gov (United States)

    Ronda, Srinivasa Reddy; Bokka, Chandra Sekhar; Ketineni, Chandrika; Rijal, Binod; Allu, Prasada Rao

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2- 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g(-1) dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6-9.5 mg· g(-1) dry cell weight). In addition, the total fatty acid (TFA) content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model.

  6. Scale-up criterion of power consumption for a surface aerator used in wastewater treatment tank

    Directory of Open Access Journals (Sweden)

    Hayder M. Issa

    2016-01-01

    Full Text Available The major part of operation costs in surface aeration basins or tanks is because of power requirements. Therefore, it is always necessary to find a dependable criterion for the predictive scale-up of power consumption measurements obtained at laboratory-scale surface aeration tanks to industrial-scale wastewater treatment surface aeration systems. A scale-up approach was proposed in this work for volumetric power consumption between geometrically similar laboratory-scale and industrial full-scale surface aeration tanks at an invariant Froude number Fr. Scale-up order between the laboratory and industrial sizes was 7.4. A mathematical correlation has been developed to estimate the volumetric power consumption and then compared with a model that already was investigated experimentally. Scale-up criterion involved the evaluation of three similarities; the geometrical, kinematic and dynamics. The scale-up basis that developed in this work led us to achieve a suitable scale-up criterion for volumetric power consumption in aeration tanks at matched surface flow condition. At matched Froude number Fr for the laboratory and industrial scales and at low and moderate turbine rotation speeds for surface aeration than 0.8 rps, complete predictions of volumetric power consumption have been achieved. The prediction by the existing previous model showed higher results than the actual values.

  7. Laboratory study of nitrification, denitrification and anammox processes in membrane bioreactors considering periodic aeration.

    Science.gov (United States)

    Abbassi, Rouzbeh; Yadav, Asheesh Kumar; Huang, Shan; Jaffé, Peter R

    2014-09-01

    The possibility of using membrane bioreactors (MBRs) in simultaneous nitrification-anammox-denitrification (SNAD) by considering periodic aeration cycles was investigated. Two separate reactors were operated to investigate the effect of different anammox biomass in the presence of nitrifying and denitrifying biomass on the final nitrogen removal efficiency. The results illustrated that the reactor with higher anammox biomass was more robust to oxygen cycling. Around 98% Total Nitrogen (TN) and 83% Total Organic Carbon (TOC) removal efficiencies were observed by applying one hour aeration over a four-hour cycle. Decreasing the aeration time to 30, 15, and 2 min during a four-hour cycle affected the final TN removal efficiencies. However, the effect of decreasing aeration on the TN removal efficiencies in the reactor with higher anammox biomass was much lower compared to the regular reactor. The nitrous oxide (N2O) emission was a function of aeration as well, and was lower in the reactor with higher anammox biomass. The results of q-PCR analysis confirmed the simultaneous co-existence of nitrifiers, anammox, and denitrifiers in both of the reactors. To simulate the TN removal in these reactors as a function of the aeration time, a new model, based on first order reaction kinetics for both denitrification and anammox was developed and yielded a good agreement with the experimental observations.

  8. Evaluation of aeration energy saving in two modified activated sludge processes.

    Science.gov (United States)

    Lee, Ingyu; Lim, Honglae; Jung, Byunghun; Colosimo, Mark F; Kim, Hyunook

    2015-12-01

    A variety of modified activated sludge processes are widely used in wastewater treatment plants (WWTPs) for removing organics and nutrients (N and P). Since energy consumption in aeration basin accounts for the major part of the overall energy usage in WWTPs, efforts have been made to find ways to reduce aeration energy. In this study, two modified activated sludge processes in a pilot scale designed for nutrient removal were evaluated for the extent of energy saving: (1) ABA(2) process - adjusting air on/off period (i.e., with a temporal change); and (2) MB-A(2)O process - changing volume ratio of aerobic tank to anoxic tank (i.e., with a spatial change). For the 1st process, the air on/off period was fixed at 60min/45min with aerobic fraction being 0.57, while for the 2nd process, the aerobic/anoxic volume ratio was reduced from 0.58 to 0.42. The results demonstrate that the effluent COD, TN, NH4(+) and TP concentrations are acceptable while reduced aeration time/volume certainly saves significant energy consumption. To the best of our knowledge, this is 1st attempt to reduce the aeration period or aeration volume to save the aeration energy in these two modified activated sludge processes. The implication of these observations is further discussed.

  9. Improving arachidonic acid fermentation by Mortierella alpina through multistage temperature and aeration rate control in bioreactor.

    Science.gov (United States)

    Gao, Min-Jie; Wang, Cheng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2016-05-18

    Effective production of arachidonic acid (ARA) using Mortierella alpina was conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6-1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13-28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L.

  10. STUDY ON BEST WAY TO RUN AND SALT TOLERANCE FOR MUSTARD TUBER WASTEWATER TREATMENT BY BIOLOGICAL AERATED FILTER%曝气生物滤池处理榨菜废水的优化运行方式及耐盐性研究

    Institute of Scientific and Technical Information of China (English)

    祝义平; 朱杰

    2011-01-01

    使用曝气生物滤池处理腌制废水,研究了有机负荷、HRT、反应温度和NaCl含量对其除污效能产生的影响.结果表明,优化有机负荷为3.3 kg·m-3·d-1;进水COD分别为小于491.8和686.9、800.4、958.7、1 111mg·L-1时,优化的HRT分别为2、4、6、9、11h;优化反应温度为25℃;耐NaCl极限质量浓度是51.84g·L-1.%BAF was used for treatment of mustard tuber wastewater, the effect of organic loading, HRT, temperature and salt (NaCl) concentration on the impact of decontamination performance were studied. The results showed that: when the excellent organic loading was 3.3 kg·m-3·d-1,reaction temperature was25 ℃ ,salt limit was 51.84 g·L-1 NaCl,the influent water COD were less than 491.8、686.9、800.4、958.7、1 111 mg·L-1,respectively, while the optimal HRT were 2、4、6、9、11 h,respectively,the optimal reaction temperature was 25 ℃, the limit concentration of NaCl was 51.84 g·L-1.

  11. 曝气生物滤池不同挂膜方法预处理微污染水源水研究%EXPERIMENTAL STUDY ON DIFFERENT BIOFILM FORMATION METHODS IN BIOLOGICAL AERATED FILTER USED FOR PRETREATMENT OF MICRO-POLLUTED WATER SOURCE

    Institute of Scientific and Technical Information of China (English)

    唐文锋; 孙丰英; 何晓文

    2011-01-01

    采用陶粒填料曝气生物滤池预处理微污染水源水,对接种挂膜和自然挂膜2种挂膜方式下挂膜时间、生物膜生长形态特征及对微污染有机物和氨氮的去除情况进行了试验.结果表明,接种挂膜可以加快系统启动,比自然挂膜启动时间减少1周左右,并且生物量较多;系统成功启动进入稳定运行期间,2种挂膜方式下的微生物形态和特征基本相同;系统稳定运行期间,2种挂膜方法启动系统均取得较好的微污染物去除效果,自然挂膜对COD的去除效果稍好于接种挂膜,接种挂膜对NH3-N的去除效果要好于自然挂膜.%BAF was used for pretreatment of micro-polluted water source. Under the different bilfilm formation methods of natural biofilm formation and inoculated biofilm formation, the time of biofilm formation, the biofilm morphology and characteristics, the removal effects of COD and NH3-N were analyzed. The results show that the inoculated biofilm formation can shorten the start-up time and the start-up time of the inoculated biofilm formation compared with the natural biofilm formation is shorted by about seven days, and the biomass is also greater. The biofilm morphology and characteristics are similar under the two different bilfilm formation methods during the stable operation of the systems. The two systems started by the two different bilfilm formation methods can both achieve better removal of micro-pollutants during the stable operation, and the removal of COD of the natural biofilm formation is slightly better than the inoculated biofilm formation, conversely, the removal of NH3-N of the inoculated biofilm formation is slightly better than the natural biofilm formation.

  12. Study of biological aerated filter and coagulative precipitation tank on reusing of medio-contaminant water%曝气生物滤池——凝沉淀组合工艺处理中度污染原水的效能

    Institute of Scientific and Technical Information of China (English)

    李文捷; 卢少勇; 王鹤立

    2006-01-01

    报道了曝气生物滤池与高效混凝沉淀组合工艺对中度污染水的处理效果.采用此组合工艺进行了郑州城市污水厂二级处理出水的2m3/h规模的中试研究,在此基础上对常熟市被污染的地表水进行了600m3/h规模的工程试验研究.中试研究和工程运行表明,中度污染水通过该处理工艺后,可取得较高的COD、氨氮、悬浮物和浊度处理效率,CODCr去除率20%-60%、氨氮去除率大于95%、悬浮物去除率大于80%,能满足电厂循环冷却水补给水的水质要求.

  13. Removal of pharmaceuticals in aerated biofilters with manganese feeding.

    Science.gov (United States)

    Zhang, Yongjun; Zhu, Hong; Szewzyk, Ulrich; Geissen, Sven Uwe

    2015-04-01

    A tertiary treatment step is required in current wastewater treatment plants to remove trace pollutants and thus to prevent their extensive occurrence in the aquatic environment. In this study, natural MnOx ore and natural zeolite were separately used to pack two lab-scale aerated biofilters, which were operated in approximately 1.5 years for the removal of frequently occurring pharmaceuticals, including carbamazepine (CBZ), diclofenac (DFC), and sulfamethoxazole (SMX), out of synthetic and real secondary effluents. Mn(2+) was added in the feeds to promote the growth of iron/manganese oxidizing bacteria which were recently found to be capable of degrading recalcitrant pollutants. An effective removal (80-90%) of DFC and SMX was observed in both biofilters after adaptation while a significant removal of CBZ was not found. Both biofilters also achieved an effective removal of spiked Mn(2+), but a limited removal of carbon and nitrogen contents. Additionally, MnOx biofilter removed 50% of UV254 from real secondary effluent, indicating a high potential on the removal of aromatic compounds.

  14. Evaluation of sequential aerated treatment of wastewater from hardboard mill

    Directory of Open Access Journals (Sweden)

    S. Videla

    1998-01-01

    Full Text Available Wastewater from a hardboard mill characterized by a high organic content (15-30 g/L COD was studied in a bench scale sequential aerated system in order to define a start up strategy. Inlet COD concentration varied from 0.5 to 25 g/L and the hydraulic retention time was maintained at 5 days. The sequential system proposed could reduce BOD, COD, TSS and phenol over 90% except when the inlet COD concentration was lower than 25 g/L.Água residual proveniente de uma indústria de tabuleiro de fibra dura caracterizada por ter um elevado conteúdo orgânico (15-30 g/L DQO foi estudada utilizando um sistema arejado seqüêncial de forma a definir uma estratégia de start up. A concentração de DQO na entrada do sistema variou na faixa de 0,5-25 g/L e o tempo de residência hidráulico foi mantido em 5 dias. O sistema seqüêncial proposto reduziu DBO, DQO, SST e fenol sobre 90% quando a concentração de DQO na entrada foi menor a 25 g/L.

  15. Fate of Pathogen Indicators During Extended Aeration Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Norshuhaila Mohamed Sunar

    2015-05-01

    Full Text Available Pathogen indicators normally used in water quality indicator because large numbers of the bacteria are always present in the faeces of humans, but are not naturally found in water. Since these bacteria don’t live long in water once outside the intestine, their presence in water means there has been recent contamination through effluent discharges or other sources. Like other enteric pathogens, a common mode of transmission for E.coli is via contaminated water, food and by direct person to person contact. Infection often causes severe bloody diarrhea, abdominal cramps, and possibly fever.  In some cases, infection can lead to kidney failure and possibly death. In order to evaluate the effieciency of extended aeration wastewater treatment plant (EAWWTP, the microbial analyses such as enumeration of E.coli and total coliform were measured. Besides, this study also involved the measurements of pH, turbidity, DO (Dissolve Oxygen, BOD (Biochemical Oxygen Demand, COD (Chemical Oxygen Demand and TSS (Total Suspended Solid. This study summarized that each treatment process provides important roles to overall effieciency of EAWWTP. The secondary treatment was proved sufficient not only on reducing pathogen indicators but for all examined parameters. Significantly, this study conclude that numbers of pathogen indicators discharges in effluent meet the regulated standard guideline after treated through the EAWWTP.

  16. A two-fluid model for violent aerated flows

    CERN Document Server

    Dias, Frédéric; Ghidaglia, Jean-Michel

    2008-01-01

    In the study of ocean wave impact on structures, one often uses Froude scaling since the dominant force is gravity. However the presence of trapped or entrained air in the water can significantly modify wave impacts. When air is entrained in water in the form of small bubbles, the acoustic properties in the water change dramatically. While some work has been done to study small-amplitude disturbances in such mixtures, little work has been done on large disturbances in air-water mixtures. We propose a basic two-fluid model in which both fluids share the same velocities and analyze some of its properties. It is shown that this model can successfully mimic water wave impacts on coastal structures. The governing equations are discretized by a second-order finite volume method. Numerical results are presented for two examples: the dam break problem and the drop test problem. It is shown that this basic model can be used to study violent aerated flows, especially by providing fast qualitative estimates.

  17. Digital filters

    CERN Document Server

    Hamming, Richard W

    1997-01-01

    Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s

  18. Modeling a full scale oxidation ditch system, coupling hydrodynamics and biological kinetics using ASM1 model

    Energy Technology Data Exchange (ETDEWEB)

    Haouech, L.; Sperandio, M.; Cock, A.; Shayeb, H.

    2009-07-01

    Optimising the aeration in oxidation ditch aims on one hand, a better wastewater quality and on the other hand, a reduction of the energy expenses of the treatment. given that the energy expenses relative to the aeration represents 60 to 80% of the operating costs of a wastewater treatment plant and given that the biological activity is strictly dependent on dissolved oxygen, the transfer of oxygen is considered as one of the key parameters of the process. (Author) 8 refs.

  19. Microorganisms interacting in a bio filter

    Energy Technology Data Exchange (ETDEWEB)

    Barba-Avila, M. D.; Flores-Tene, F. J.; Moreno-Terrazas, R.; Ramirez-Lopez, E. M.

    2009-07-01

    Biofilm microorganisms developed on a bio filter support media allow the metabolism of volatile organic compounds (VOCs) to carbon dioxide and water. VOCs are present in polluted gaseous streams for varied industrial activities. The main objective of this study was to identify the microorganisms present in the biofilm developed on a bio filter support media using molecular biology techniques. (Author)

  20. Mixing regime as a key factor to determine DON formation in drinking water biological treatment.

    Science.gov (United States)

    Lu, Changqing; Li, Shuai; Gong, Song; Yuan, Shoujun; Yu, Xin

    2015-11-01

    Dissolved organic nitrogen (DON) can act as precursor of nitrogenous disinfection by-products formed during chlorination disinfection. The performances of biological fluidized bed (continuous stirred tank reactor, CSTR) and bio-ceramic filters (plug flow reactor, PFR) were compared in this study to investigate the influence of mixing regime on DON formation in drinking water treatment. In the shared influent, DON ranged from 0.71mgL(-1) to 1.20mgL(-1). The two biological fluidized bed reactors, named BFB1 (mechanical stirring) and BFB2 (air agitation), contained 0.12 and 0.19mgL(-1) DON in their effluents, respectively. Meanwhile, the bio-ceramic reactors, labeled as BCF1 (no aeration) and BCF2 (with aeration), had 1.02 and 0.81mgL(-1) DON in their effluents, respectively. Comparative results showed that the CSTR mixing regime significantly reduced DON formation. This particular reduction was further investigated in this study. The viable/total microbial biomass was determined with propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) and qPCR, respectively. The results of the investigation demonstrated that the microbes in BFB2 had higher viability than those in BCF2. The viable bacteria decreased more sharply than the total bacteria along the media depth in BCF2, and DON in BCF2 accumulated in the deeper media. These phenomena suggested that mixing regime determined DON formation by influencing the distribution of viable, total biomass, and ratio of viable biomass to total biomass.

  1. CAVITATION CHARACTERISTICS OF HIGH VELOCITY FLOW WITH AND WITHOUT AERATION ON THE ORDER OF 50 m/s

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Experimental study of cavitation characteristics with and without aeration was conducted at the flow velocity 50m/s in the non-circulating type water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology. Variations of pressure and cavitation number with air concentration, pressure waveforms as well as cavitation erosion level of concrete specimen with and without aeration were obtained. The effects of cavitation control by aeration were analyzed.

  2. Reducing aeration energy consumption in a large-scale membrane bioreactor: Process simulation and engineering application.

    Science.gov (United States)

    Sun, Jianyu; Liang, Peng; Yan, Xiaoxu; Zuo, Kuichang; Xiao, Kang; Xia, Junlin; Qiu, Yong; Wu, Qing; Wu, Shijia; Huang, Xia; Qi, Meng; Wen, Xianghua

    2016-04-15

    Reducing the energy consumption of membrane bioreactors (MBRs) is highly important for their wider application in wastewater treatment engineering. Of particular significance is reducing aeration in aerobic tanks to reduce the overall energy consumption. This study proposed an in situ ammonia-N-based feedback control strategy for aeration in aerobic tanks; this was tested via model simulation and through a large-scale (50,000 m(3)/d) engineering application. A full-scale MBR model was developed based on the activated sludge model (ASM) and was calibrated to the actual MBR. The aeration control strategy took the form of a two-step cascaded proportion-integration (PI) feedback algorithm. Algorithmic parameters were optimized via model simulation. The strategy achieved real-time adjustment of aeration amounts based on feedback from effluent quality (i.e., ammonia-N). The effectiveness of the strategy was evaluated through both the model platform and the full-scale engineering application. In the former, the aeration flow rate was reduced by 15-20%. In the engineering application, the aeration flow rate was reduced by 20%, and overall specific energy consumption correspondingly reduced by 4% to 0.45 kWh/m(3)-effluent, using the present practice of regulating the angle of guide vanes of fixed-frequency blowers. Potential energy savings are expected to be higher for MBRs with variable-frequency blowers. This study indicated that the ammonia-N-based aeration control strategy holds promise for application in full-scale MBRs.

  3. Stable isotope probing and dynamic loading experiments provide insight into the ecophysiology of novel ammonia oxidizers in rapid gravity sand filters

    OpenAIRE

    Fowler, Jane; Palomo, Alejandro; Gülay, Arda; Tatari, Karolina; Thamdrup, Bo; Albrechtsen, Hans-Jørgen; Sørensen, Søren; Barth F. Smets

    2016-01-01

    Nitrification is often the dominant microbial process in rapid gravity sand filters (RSF), used to treat aerated groundwater to produce drinking water. RSFs harbor diverse microbial communities including a range of ammonia oxidizing clades; Betaproteobacteria (Nitrosomonas, Nitrosospira), Archaea, diverse potentially ammonia oxidizing heterotrophs and abundant Nitrospira spp., recently shown to comprise both canonical nitrite oxidizing as well as complete ammonium oxidizing (comammox) types. ...

  4. A new dynamic model for highly efficient mass transfer in aerated bioreactors and consequences for kLa identification.

    Science.gov (United States)

    Müller, Stefan; Murray, Douglas B; Machne, Rainer

    2012-12-01

    , potentially confounding the determination of the "biological enhancement" of mass transfer. Our new model provides an improved theoretical framework that can be readily applied to aerated bioreactors in research and biotechnology.

  5. Impact of post-infiltration soil aeration at different growth stages of sub-surface trickle-irrigated tomato plants

    Science.gov (United States)

    Li, Yuan; Jia, Zong-xia; Niu, Wen-Quan; Wang, Jing-wei

    2016-07-01

    Sensitivity to low rhizosphere soil aeration may change over time and therefore plant response may also depend on different growth stages of a crop. This study quantified effects of soil aeration during 5 different periods, on growth and yield of trickle-irrigated potted single tomato plants. Irrigation levels were 0.6 to 0.7 (low level) or 0.7 to 0.8 (high level) of total water holding capacity of the pots. Soil was aerated by injecting 2.5 l of air into each pot through the drip tubing immediately after irrigation. Fresh fruit yield, above ground plant dry weight, plant height, and leaf area index response to these treatments were measured. For all these 4 response variables, means of post-infiltration aeration between 58 to 85 days after sowing were 13.4, 43.5, 13.7, and 37.7% higher than those for the non-aerated pots, respectively. The results indicated that: post-infiltration soil aeration can positively impact the yield and growth of sub-surface trickle-irrigated potted tomato plants; positive effects on plant growth can be obtained with aeration during the whole growth period or with aeration for partial periods; positive growth effects of partial periods of aeration appears to persist and result in yield benefit.

  6. Optimizing aeration rates for minimizing membrane fouling and its effect on sludge characteristics in a moving bed membrane bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Yousef, E-mail: yrahimi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Torabian, Ali, E-mail: atorabi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Mehrdadi, Naser, E-mail: mehrdadi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Habibi-Rezaie, Mehran, E-mail: mhabibi@khayam.ut.ac.ir [Department of Biotechnology, Faculty of Biology, College of Science, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Pezeshk, Hamid, E-mail: pezeshk@khayam.ut.ac.ir [Department of Statistics, Faculty of Mathematics and Computer, College of Science, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Nabi-Bidhendi, Gholam-Reza, E-mail: ghhendi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of)

    2011-02-28

    Research highlights: {yields} There is an optimum aeration rate in the MBMBR process compartments. {yields} Optimum aeration rate maximizes nutrients removal. {yields} Optimum aeration rate minimizes membrane fouling. {yields} Both aeration rates in MBBR and membrane compartment can affect on membrane permeability. - Abstract: In MBR processes, sufficient aeration is necessary to maintain sustainable flux and to retard membrane fouling. Membrane permeability, sludge characteristics, nutrient removal and biomass growth at various air flow rates in the membrane and moving bed biofilm reactor (MBBR) compartments were studied in a pilot plant. The highest nitrogen and phosphorous removal rates were found at MBBR aeration rates of 151 and 85 L h{sup -1} and a specific aeration demand per membrane area (SAD{sub m}) of 1.2 and 0.4m{sub air}{sup 3} m{sup -2} h{sup -1}, respectively. A linear correlation was found between the amount of attached biofilm and the nutrient removal rate. The aeration rate in the MBBR compartment and SAD{sub m} significantly influenced the sludge characteristics and membrane permeability. The optimum combination of the aeration rate in the MBBR compartment and SAD{sub m} were 151 L h{sup -1} and 0.8-1.2m{sub air}{sup 3}m{sub membrane}{sup -2} h{sup -1}, respectively.

  7. Effect of artificial aeration on the performance of vertical-flow constructed wetland treating heavily polluted river water

    Institute of Scientific and Technical Information of China (English)

    Huiyu Dong; Zhimin Qiang; Tinggang Li; Hui Jin; Weidong Chen

    2012-01-01

    Three lab-scale vertical-flow constructed wetlands (VFCWs),including the non-aerated (NA),intermittently aerated (IA) and continuously aerated (CA) ones,were operated at different hydraulic loading rates (HLRs) to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water.Results indicated that artificial aeration increased the dissolved oxygen (DO) concentrations in IA and CA,which significantly favored the removal of organic matter and NH4+-N.The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen (TN).Although the removal efficiencies of CODcr,NH4+-N and TN in the three VFCWs all decreased with an increase in HLR,artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings.The maximal removal efficiencies of CODcr,NH4+-N and total phosphorus (TP) (i.e.,81%,87% and 37%,respectively) were observed in CA at 19 cm/day HLR,while the maximal TN removal (i.e.,57%) was achieved in IA.Although the improvement of artificial aeration on TP removal was limited,this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted eiver water,particularly at a high HLR.

  8. Glucose metabolism in Lactococcus lactis MG1363 under different aeration conditions: Requirement of acetate to sustain growth under microaerobic conditions

    DEFF Research Database (Denmark)

    Nordkvist, Mikkel; Jensen, N.B.S.; Villadsen, John

    2003-01-01

    Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation...... with air was used as the reference). The maximum specific growth rate was high (0.78 to 0.91 h(-1)) under all aeration conditions but decreased with increasing aeration, and more than 90% of the glucose was converted to lactate. However, a shift in by-product formation was observed. Increasing aeration...

  9. THE INFLUENCE OF RECIPE COMPONENTS ON QUALITY PARAMETERS OF AERATED DOUGH AND WHOLEGRAIN BREAD FROM CHICKPEA SEEDS

    Directory of Open Access Journals (Sweden)

    G. O. Magomedov

    2015-01-01

    Full Text Available The article presents the results of studying the effect of using table salt, apple juice and citric acid on quality parameters of aerated dough and bread prepared by mechanical leavening. The wholegrain flour from chickpea seeds has been used to prepare dough. The amount of salt is in the range from 1 to 3 %, apple juice from 5 to 25%, citric acid 0.05 to 0.2 % over the weight of the flour. The working mechanism of recipe components on the process of foaming while kneading of the semi-finished products of chickpea flour has been identified. The increase of their amount leads to increase of active acidity of the test and brings the protein pH to isoelectric point. Thus increasing the foaming capacity of the albuminous substances while kneading the semis. It has been founded that the maximum foaming capacity of the semis is achieved at pH 5.5. At the same time a decrease in the bulk density of the dough and the increase in specific volume of the baked product. In this case, the samples are characterized by lower bulk density (0.32 g / cm3 , and maximum specific volume of finished product (365 cm3 / 100 g. The reasonable amount of components in the bread recipe: table salt 1.5 %, apple juice 5.0 %, citric acid 0.1 % over weight of flour has been recommended. The data obtained form the basis for the development of technology of aerated bread "Atreus" with higher nutritional and biological value. The degree of satisfaction of adult daily need of 100 g of the product is, %: protein 17, dietary fiber 39, magnesium 21, phosphorus 28, iron 30, potassium, thiamine and riboflavin 18. The product is recommended for mass consumption in order to enrich dietary intake with protein, dietary fiber. minerals and vitamins.

  10. Neutrophilic Iron Oxidizing Bacteria: Occurrence and Relevance in Biological Drinking Water Treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen;

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully ...

  11. Neutrophilic iron-oxidizing bacteria: occurrence and relevance in biological drinking water treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen;

    2013-01-01

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully ...

  12. Analysis of Process Gases and Trace Contaminants in Membrane-Aerated Gaseous Effluent Streams.

    Science.gov (United States)

    Coutts, Janelle L.; Lunn, Griffin Michael; Meyer, Caitlin E.

    2015-01-01

    In membrane-aerated biofilm reactors (MABRs), hollow fibers are used to supply oxygen to the biofilms and bulk fluid. A pressure and concentration gradient between the inner volume of the fibers and the reactor reservoir drives oxygen mass transport across the fibers toward the bulk solution, providing the fiber-adhered biofilm with oxygen. Conversely, bacterial metabolic gases from the bulk liquid, as well as from the biofilm, move opposite to the flow of oxygen, entering the hollow fiber and out of the reactor. Metabolic gases are excellent indicators of biofilm vitality, and can aid in microbial identification. Certain gases can be indicative of system perturbations and control anomalies, or potentially unwanted biological processes occurring within the reactor. In confined environments, such as those found during spaceflight, it is important to understand what compounds are being stripped from the reactor and potentially released into the crew cabin to determine the appropriateness or the requirement for additional mitigation factors. Reactor effluent gas analysis focused on samples provided from Kennedy Space Center's sub-scale MABRs, as well as Johnson Space Center's full-scale MABRs, using infrared spectroscopy and gas chromatography techniques. Process gases, such as carbon dioxide, oxygen, nitrogen, nitrogen dioxide, and nitrous oxide, were quantified to monitor reactor operations. Solid Phase Microextraction (SPME) GC-MS analysis was used to identify trace volatile compounds. Compounds of interest were subsequently quantified. Reactor supply air was examined to establish target compound baseline concentrations. Concentration levels were compared to average ISS concentration values and/or Spacecraft Maximum Allowable Concentration (SMAC) levels where appropriate. Based on a review of to-date results, current trace contaminant control systems (TCCS) currently on board the ISS should be able to handle the added load from bioreactor systems without the need

  13. Convergent Filter Bases

    Directory of Open Access Journals (Sweden)

    Coghetto Roland

    2015-09-01

    Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

  14. Convergent Filter Bases

    OpenAIRE

    Coghetto Roland

    2015-01-01

    We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres) and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections).

  15. Achieving ethanol-type fermentation for hydrogen production in a granular sludge system by aeration.

    Science.gov (United States)

    Zhang, Song; Liu, Min; Chen, Ying; Pan, Yu-Ting

    2017-01-01

    To investigate the effects of aeration on hydrogen-producing granular system, experiments were performed in two laboratory-scale anaerobic internal circulation hydrogen production (AICHP) reactors. The preliminary experiment of Reactor 1 showed that direct aeration was beneficial to enhancing hydrogen production. After the direct aeration was implied in Reactor 2, hydrogen production rate (HPR) and hydrogen content were increased by 100% and 60%, respectively. In addition, mixed-acid fermentation was transformed into typical ethanol-type fermentation (ETF). Illumina MiSeq sequencing shows that the direct aeration did not change the species of hydrogen-producing bacteria but altered their abundance. Hydrogen-producing bacteria and ethanol-type fermentative bacteria were increased by 24.5% and 146.3%, respectively. Ethanoligenens sp. sharply increased by 162.2% and turned into predominant bacteria in the system. These findings indicated that appropriate direct aeration might be a novel and promising way to obtain ETF and enhance hydrogen production in practical use.

  16. EXPERIMENTAL AND NUMERICAL SIMULATION OF THREE-PHASE FLOW IN AN AERATION TANK

    Institute of Scientific and Technical Information of China (English)

    Cheng Wen; Zhou Xiao-de; Song Ce; Min Tao; Murai Yuichi; Yamamoto Fujio

    2003-01-01

    Aeration plays an important role in the treatment of activated sludge due to the interactions among bubbles, sewage and activated sludge in an aeration tank. The aeration performance is directly concerned with the efficiency of sewage disposal. So the three-dimensional two-fluid model was established with emphasis on the phase interaction terms in this paper. This model, as an extension of the two-phase flow model, involved the motion laws of three-phases, and was compared with experimental studies. The finite volume method was used in the numerical simulation of gas-liquid two-phase flow and gas-liquid-solid three-phase flow. In order to discuss the influence of gas-phase, liquid-phase and solid-phase motions in an aeration tank on the sewage disposal, three kinds of boundary and initial conditions were adopted. The simulated results of the flow structure show qualitatively good agreement with the experimental data. And the theoretical basis for designing the best aeration tank was discussed according to the simulated results.

  17. [Effect of Intermittent Aeration on Nitrogen Removal Efficiency in Vertical Subsurface Flow Constructed Wetland].

    Science.gov (United States)

    Wang, Jian; Li, Huai-zheng; Zhen, Bao-chong; Liu, Zhen-dong

    2016-03-15

    One-stage vertical subsurface flow constructed wetlands (CWs) were used to treat effluent from grit chamber in municipal wastewater treatment plant. The CW was divided into aerobic zone and anoxic zone by means of raising the effluent level and installing a perforated pipe. Two parameters (the ratio of aeration time and nonaeration time, aeration cycle) were optimized in the experiment to enhance nitrogen removal efficiency. The results suggested that the removal rates of COD and NH₄⁺-N increased while TN showed a trend of first increasing and then decreasing with the increasing ratio. When the ratio was 3:1, the C/N value in the anoxic zone was 4. 8. And the TN effluent concentration was 15.8 mg · L⁻¹ with the highest removal rate (62.1%), which was increased by 12.7% compared with continuous aeration. As the extension of the aeration cycle, the DO effluent concentration as well as the removal rates of COD and NH: -N declined gradually. The TN removal rate reached the maximum (65.5%) when the aeration cycle was 6h. However, the TN removal rate dropped rapidly when the cycle exceeded the hydraulic retention time in the anoxic zone.

  18. Influence of aeration and initial water thickness on axial velocity attenuation of jet flows

    Institute of Scientific and Technical Information of China (English)

    Wang-ru WEI; Jun DENG; Bin LIU

    2013-01-01

    With the development of ski-jump energy dissipation for high and large discharge among the hydraulic projects,the effects of characteristics of water flow on energy dissipation are increasingly important.In the present study,the effects of aeration and the initial water thickness on axial velocity attenuation of jet flow were analyzed,using variance analysis and numerical calculated methods.From the analysis of test data,both of the air concentration and initial water thickness are sensitive factors for the axial velocity attenuation of jet flow along the axial way,and there is no significant interaction effect between the aeration and initial water thickness.Aeration has a more significant effect on the axial velocity attenuation of jet flow.Decreasing the initial water thickness of jet flow can reduce the length of jet core,and make the initial position of axial velocity attenuation closer to the nozzle exit.The numerical calculation results show that aeration can contribute to the enhancement of entrainment ability of jet flow,which may improve the interaction between jet flow and surroundings.For ski-jump energy dissipation among the hydraulic projects,combining aeration with decreasing initial water thickness of jet flow is an effective way to enhance the rate of axial velocity attenuation.

  19. Municipal waste stabilization in a reactor with an integrated active and passive aeration system.

    Science.gov (United States)

    Kasinski, Slawomir; Slota, Monika; Markowski, Michal; Kaminska, Anna

    2016-04-01

    To test whether an integrated passive and active aeration system could be an effective solution for aerobic decomposition of municipal waste in technical conditions, a full-scale composting reactor was designed. The waste was actively aerated for 5d, passively aerated for 35 d, and then actively aerated for 5d, and the entire composting process was monitored. During the 45-day observation period, changes in the fractional, morphological and physico-chemical characteristics of the waste at the top of the reactor differed from those in the center of the reactor. The fractional and morphological analysis made during the entire process of stabilization, showed the total reduction of organic matter measured of 82 wt% and 86 wt% at the respective depths. The reduction of organic matter calculated using the results of Lost of Ignition (LOI) and Total Organic Carbon (TOC) showed, respectively, 40.51-46.62% organic matter loss at the top and 45.33-53.39% in the center of the reactor. At the end of the process, moisture content, LOI and TOC at the top were 3.29%, 6.10% and 4.13% higher, respectively, than in the center. The results showed that application of passive aeration in larger scale simultaneously allows the thermophilic levels to be maintained during municipal solid waste composting process while not inhibiting microbial activity in the reactor.

  20. Nitrogen transformations and retention in planted and artificially aerated constructed wetlands.

    Science.gov (United States)

    Maltais-Landry, Gabriel; Maranger, Roxane; Brisson, Jacques; Chazarenc, Florent

    2009-02-01

    Nitrogen (N) processing in constructed wetlands (CWs) is often variable, and the contribution to N loss and retention by various pathways (nitrification/denitrification, plant uptake and sediment storage) remains unclear. We studied the seasonal variation of the effects of artificial aeration and three different macrophyte species (Phragmites australis, Typha angustifolia and Phalaris arundinacea) on N processing (removal rates, transformations and export) using experimental CW mesocosms. Removal of total nitrogen (TN) was higher in summer and in planted and aerated units, with the highest mean removal in units planted with T. angustifolia. Export of ammonium (NH(4)(+)), a proxy for nitrification limitation, was higher in winter, and in unplanted and non-aerated units. Planted and aerated units had the highest export of oxidized nitrogen (NO(y)), a proxy for reduced denitrification. Redox potential, evapotranspiration (ETP) rates and hydraulic retention times (HRT) were all predictors of TN, NH(4)(+) and NO(y) export, and significantly affected by plants. Denitrification was the main N sink in most treatments accounting for 47-62% of TN removal, while sediment storage was dominant in unplanted non-aerated units and units planted with P. arundinacea. Plant uptake accounted for less than 20% of the removal. Uncertainties about the long-term fate of the N stored in sediments suggest that the fraction attributed to denitrification losses could be underestimated in this study.

  1. Performance of a fixed-bed biofilm reactor with microbubble aeration in aerobic wastewater treatment.

    Science.gov (United States)

    Zhang, Lei; Liu, Junliang; Liu, Chun; Zhang, Jing; Yang, Jingliang

    2016-01-01

    Microbubble aeration is supposed to be highly efficient for oxygen supply in aerobic wastewater treatment. In the present study, the performance of a fixed-bed biofilm reactor microbubble-aerated using a Shirasu porous glass (SPG) membrane system was investigated when treating synthetic municipal wastewater. The biofilm formation on the carriers was enhanced with microbubble aeration due to the strong adhesion of microbubbles to the solid surface. The dissolved oxygen concentration, the removals of chemical oxygen demand (COD) and nitrogen, and the oxygen utilization efficiency were influenced by the organic loading rate at a certain oxygen supply capacity. The relatively optimal organic loading rate was determined as 0.82 kgCOD/(m(3)d) when the oxygen supply capacity was 0.93 kgO(2)/(m(3)d), where COD and ammonia removal efficiencies were 91.7% and 53.9%, respectively. The corresponding SPG membrane area-based COD removal capacity was 6.88 kgCOD/(m(2)d). The oxygen utilization efficiency of microbubble aeration was obviously higher compared to conventional bubble aeration. The simultaneous nitrification and denitrification occurred in the biofilm reactor and the total nitrogen removal efficiency of 50.4% was achieved under these conditions. In addition, the increase in air supply capacity of the SPG membrane system was suggested to improve its energy utilization efficiency.

  2. NOVEL MICROWAVE FILTER DESIGN TECHNIQUES.

    Science.gov (United States)

    ELECTROMAGNETIC WAVE FILTERS, MICROWAVE FREQUENCY, PHASE SHIFT CIRCUITS, BANDPASS FILTERS, TUNED CIRCUITS, NETWORKS, IMPEDANCE MATCHING , LOW PASS FILTERS, MULTIPLEXING, MICROWAVE EQUIPMENT, WAVEGUIDE FILTERS, WAVEGUIDE COUPLERS.

  3. Thermal Response Of An Aerated Concrete Wall With Micro-Encapsulated Phase Change Material

    Directory of Open Access Journals (Sweden)

    Halúzová Dušana

    2015-06-01

    Full Text Available For many years Phase Change Materials (PCM have attracted attention due to their ability to store large amounts of thermal energy. This property makes them a candidate for the use of passive heat storage. In many applications, they are used to avoid the overheating of the temperature of an indoor environment. This paper describes the behavior of phase change materials that are inbuilt in aerated concrete blocks. Two building samples of an aerated concrete wall were measured in laboratory equipment called “twin-boxes”. The first box consists of a traditional aerated concrete wall; the second one has additional PCM micro-encapsulated in the wall. The heat flux through the wall was measured and compared to simulation results modeled in the ESP-r program. This experimental measurement provides a foundation for a model that can be used to analyze further building constructions.

  4. Expired CO2 levels indicate degree of lung aeration at birth.

    Directory of Open Access Journals (Sweden)

    Stuart B Hooper

    Full Text Available As neonatal resuscitation critically depends upon lung aeration at birth, knowledge of the progression of this process is required to guide ongoing care. We investigated whether expired CO2 (ECO2 levels indicate the degree of lung aeration immediately after birth in two animal models and in preterm infants. Lambs were delivered by caesarean section and ventilated from birth. In lambs, ECO2 levels were significantly (p10 mmHg 28 (median (21-36 seconds before the heart rate increased above 100 beats per minute. These data demonstrate that ECO2 levels can indicate the relative degree of lung aeration after birth and can be used to clinically assess ventilation in the immediate newborn period.

  5. Study on Migration and Transformation Rule of Organic Pollutants (COD) in Aerated Zone

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Collecting waste water with a certain concentration of organic pollutants COD (chemical oxygen demand), static adsorption, static biodegradation and dynamic soil column experiments were made in laboratory, we researched migration and transformation of COD in aerated zone, and put forward a mathematical model showing the process. The results show that adsorption of organism in aerated zone is linear, which is represented by Henry's law s=Kdc+sd, adsorption coefficient Kd =0. 069 3;biodegradation diagram accord basically with first-order kinetics equation c=c0e-K1t , biodegradation coefficient K1 = 0. 049 9 d-1; dispersion coefficient D= 0. 002 42 m2/d in experiments. The migration and transformation of organic pollutants (COD) in aerated zone jointly result from many factors such as dispersion, adsorption and biodegradation etc..

  6. A Novel Surface Aeration Configuration for Improving Gas—Liquid Mass Transfer

    Institute of Scientific and Technical Information of China (English)

    YUGengzhi; MAZaisha; 等

    2002-01-01

    A novel surface aeration configuration featured with a self-rotating and floating baffle (SRFB) and a Rushton disk turbine (DT) with a perforated disk has been developed. The SRFB, consisted of 12 fan blades twisted by an angle of 30° to the horizontal plane, is incorporated onto the impeller shaft to improve gas entrainment, bubble breakup, mixing in a φ154mm agitated vessel. This new configuration is compared to the conventional DT surface aeration experimentally. The results suggest that the critical impeller speed for onset of gas entrainments is lower for the new configuration and it demands greater power consumption. Moreover, the SRFB system produces 30%-68% higher volumetric mass transfer coefficient per unit power input than that obtained in the conventional DT surface aerator under the same operation conditions.

  7. ON NECESSITY OF PLACING AN AERATOR IN THE BOTTOM DISCHARGE TUNNEL AT THE LONGTAN HYDROPOWER STATION

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; WU Wei-wei; RUAN Shi-ping

    2006-01-01

    The air entrainment for avoiding cavitation damage has been widely used in long free flow tunnels. It is crucial to determine whether an aerator is needed for shorter tunnels. In this article, the bottom discharge tunnel at the Longtan Hydropower Station was involved, for which the free flow tunnel section was only 50.00 m long. The cavitation in the tunnel with and without the aerator was investigated using the physical models of the scale 1/30, through the measurements of cavitation noise. The experimental results show that it is necessary to place the aerator at the inlet of the free flow section for higher reservoir level to protect this tunnel from cavitation damage.

  8. RBF methods for solving laterally averaged Saint Venant equations: application to eutrophication prevention through aeration

    Science.gov (United States)

    Halassi, A.; Ouazar, D.; Taik, A.

    2015-10-01

    A vertical 2Dxz laterally averaged hydrodynamic model is presented in this paper to study the aeration process in lakes. The system exhibits highly nonlinear behaviour due to the phenomena involved such as stratification, air concentration, and convective terms. The suggested model is used to simulate mechanical aeration to overcome and prevent the eutrophication in lakes. The multiquadric radial basis functions are used to solve numerically the governing partial differential equations. Because of the difficulty and the complexity when choosing a suitable shape parameter in radial basis functions, an alternative way is introduced in this work to overcome these difficulties. A validation study is carried out using several test examples, including Poisson, Navier-Stokes and transport equations. Finally, the proposed model is first applied to simulate a squared domain aeration problem and then a real test case has been considered. The obtained results are in good agreement with the results reported in the literature.

  9. Influence of agitation speeds and aeration rates on the Xylanase activity of Aspergillus niger SS7

    Directory of Open Access Journals (Sweden)

    Yasser Bakri

    2011-08-01

    Full Text Available In this study, the effect of agitation and aeration rates on xylanase activity of Aspergillus niger SS7 in 3-litre stirred tank bioreactor was investigated. The agitation rates tested were 100, 200 and 300 rpm at each airflow rates of 0.5, 1.0 and 1.5 vvm. The maximum xylanase activity in mono- agitator system was at the agitation speed of 200 rpm and aeration rate of 1.0 vvm. In bi-agitator system, at low agitation speed (100 rpm, the xylanase activity was enhanced by 13% compared to mono- agitator system for an aeration rate of 1.0 vvm. Xylanase productivity in continuous culture was higher by approximately 3.5 times than in batch culture.

  10. Computational Fluid Dynamics Modelling of Hydraulics and Sedimentation in Process Reactors during Aeration Tank Settling

    DEFF Research Database (Denmark)

    Jensen, M.D.; Ingildsen, P.; Rasmussen, Michael R.;

    2006-01-01

    Aeration tank settling is a control method allowing settling in the process tank during highhydraulic load. The control method is patented. Aeration tank settling has been applied in several wastewater treatment plants using the present design of the process tanks. Some process tank designs...... haveshown to be more effective than others. To improve the design of less effective plants, computational fluiddynamics (CFD) modelling of hydraulics and sedimentation has been applied. This paper discusses theresults at one particular plant experiencing problems with partly short-circuiting of the inlet...... and outletcausing a disruption of the sludge blanket at the outlet and thereby reducing the retention of sludge in theprocess tank. The model has allowed us to establish a clear picture of the problems arising at the plantduring aeration tank settling. Secondly, several process tank design changes have been...

  11. Miniaturized dielectric waveguide filters

    Science.gov (United States)

    Sandhu, Muhammad Y.; Hunter, Ian C.

    2016-10-01

    Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

  12. Evaluation on aeration performance of movable solar aerator%移动式太阳能增氧机的增氧性能评价

    Institute of Scientific and Technical Information of China (English)

    吴宗凡; 程果锋; 王贤瑞; 刘兴国; 张拥军; 邹海生; 唐荣

    2014-01-01

    为改善池塘养殖环境,设计了一种移动式太阳能增氧机,由光伏供电装置和水面行走装置搭载涌浪机而成,能在水面沿钢丝绳移动并利用涌浪机的波浪增氧和水层交换作用,大范围扰动水体并为池塘增氧。该研究的目的是通过机械增氧效率检测、提水能力测定和池塘增氧能力测定3个试验,评估太阳能增氧机的机械增氧性能、水层交换性能和实际应用效果,以期全面了解移动增氧机增氧能力。结果表明,该移动式太阳能增氧机最大机械增氧能力为1.24 kg/h,动力效率2.59 kg/(kW·h);最大提水能力1254.4 m3/h,提水动力效率2613.3 m3/(kW·h);并在晴好天气白天(09:00—19:00),在对照组底层溶氧为3.1~3.8 mg/L时,大幅度提升池塘底层溶氧水平,最高时达7.8 mg/L,维持池塘上下溶氧均匀度72%~84%,极大改善了底层溶氧环境。数据表明移动式太阳能增氧机具有良好的机械增氧和水层交换性能,因而能有效改善池塘底层溶氧环境,提高上下水体溶氧均匀度。该研究结果可为太阳能增氧机的进一步推广应用提供数据支撑。%In pond aquaculture, it is usually necessary in sunny noon that running aerator stirs pond water, so that the supersaturated dissolved oxygen (DO) from phytoplankton’s photosynthesis in upper water can be transferred into the relatively anoxic bottom, reducing the“oxygen debt”of bottom water and preventing fish hypoxia at the next early morning. However, this approach consumes a lot of electric energy and has low efficiency. To improve the ecological state of aquaculture ponds and save electric energy, a movable solar aerator was designed and developed. This machine is solar-powered and can move upon the water, and mainly consists of a photovoltaic power system, a water walking device, and a wave aerator. The photovoltaic power system provides power for the entire machine

  13. Ammonia-based intermittent aeration control optimized for efficient nitrogen removal.

    Science.gov (United States)

    Regmi, Pusker; Bunce, Ryder; Miller, Mark W; Park, Hongkeun; Chandran, Kartik; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

    2015-10-01

    This work describes the development of an intermittently aerated pilot-scale process (V = 0.45 m(3) ) operated for optimized efficient nitrogen removal in terms of volume, supplemental carbon and alkalinity requirements. The intermittent aeration pattern was controlled using a strategy based on effluent ammonia concentration set-points. The unique feature of the ammonia-based aeration control was that a fixed dissolved oxygen (DO) set-point was used and the length of the aerobic and anoxic time (anoxic time ≥25% of total cycle time) were changed based on the effluent ammonia concentration. Unlike continuously aerated ammonia-based aeration control strategies, this approach offered control over the aerobic solids retention time (SRT) to deal with fluctuating ammonia loading without solely relying on changes to the total SRT. This approach allowed the system to be operated at a total SRT with a small safety factor. The benefits of operating at an aggressive SRT were reduced hydraulic retention time (HRT) for nitrogen removal. As a result of such an operation, nitrite oxidizing bacteria (NOB) out-selection was also obtained (ammonia oxidizing bacteria [AOB] maximum activity: 400 ± 79 mgN/L/d, NOB maximum activity: 257 ± 133 mgN/L/d, P ammonia (COD/NH4 (+) -N) ratio of 10.2 ± 2.2 at 25°C within the hydraulic retention time (HRT) of 4 h and within a total SRT of 5-10 days. The TIN removal efficiency up to 91% was observed during the study, while effluent TIN was 9.6 ± 4.4 mgN/L. Therefore, this pilot-scale study demonstrates that application of the proposed on-line aeration control is capable of relatively high nitrogen removal without supplemental carbon and alkalinity addition at a low HRT.

  14. Modelling the link amongst fine-pore diffuser fouling, oxygen transfer efficiency, and aeration energy intensity.

    Science.gov (United States)

    Garrido-Baserba, Manel; Sobhani, Reza; Asvapathanagul, Pitiporn; McCarthy, Graham W; Olson, Betty H; Odize, Victory; Al-Omari, Ahmed; Murthy, Sudhir; Nifong, Andrea; Godwin, Johnnie; Bott, Charles B; Stenstrom, Michael K; Shaw, Andrew R; Rosso, Diego

    2017-03-15

    This research systematically studied the behavior of aeration diffuser efficiency over time, and its relation to the energy usage per diffuser. Twelve diffusers were selected for a one year fouling study. Comprehensive aeration efficiency projections were carried out in two WRRFs with different influent rates, and the influence of operating conditions on aeration diffusers' performance was demonstrated. This study showed that the initial energy use, during the first year of operation, of those aeration diffusers located in high rate systems (with solids retention time - SRT-less than 2 days) increased more than 20% in comparison to the conventional systems (2 > SRT). Diffusers operating for three years in conventional systems presented the same fouling characteristics as those deployed in high rate processes for less than 15 months. A new procedure was developed to accurately project energy consumption on aeration diffusers; including the impacts of operation conditions, such SRT and organic loading rate, on specific aeration diffusers materials (i.e. silicone, polyurethane, EPDM, ceramic). Furthermore, it considers the microbial colonization dynamics, which successfully correlated with the increase of energy consumption (r(2):0.82 ± 7). The presented energy model projected the energy costs and the potential savings for the diffusers after three years in operation in different operating conditions. Whereas the most efficient diffusers provided potential costs spanning from 4900 USD/Month for a small plant (20 MGD, or 74,500 m(3)/d) up to 24,500 USD/Month for a large plant (100 MGD, or 375,000 m(3)/d), other diffusers presenting less efficiency provided spans from 18,000USD/Month for a small plant to 90,000 USD/Month for large plants. The aim of this methodology is to help utilities gain more insight into process mechanisms and design better energy efficiency strategies at existing facilities to reduce energy consumption.

  15. Relationship between ecosystem respiration and aeration constant in open channel dissolved oxygen analysis

    Science.gov (United States)

    Parker, S. J.; Butler, A. P.; Heppell, C. M.

    2015-12-01

    Using the open channel diel method of Odum (1956) and the night-time regression method (Hornberger and Kelly, 1985), we analysed a time series of dissolved oxygen (DO) in two slow flowing streams for a two month period in summer 2014 and obtained values for ecosystem respiration and the aeration constant for each day in the period. We then used the standard dissolved oxygen lumped model to generate a DO time series behaviour for one of those rivers selecting respiration and aeration parameters by randomly sampling from the values obtained from the data. Two synthetic time series were created, one where respiration and aeration were independent of temperature and a second where respiration and aeration were affected by temperature according to the modified Arrhenius relationship. With these two synthetic time series, we again recovered the respiration and aeration input parameters using the night- time regression method and compared those recovered parameters with the input parameters. Because the simulations were conducted with parameters that were known, the values recovered using the night-time regression method (i.e post-simulation) could be compared with parameters driving the simulation (i.e. pre-simulation input values). For values based on data, we found a strong correlation between the aeration constant and respiration for both rivers. For the synthetic time series, no such correlation was found, either with the temperature independent or temperature dependent time series. The night-time regression method also recovered perfectly the input parameters, so the correlation was not brought about as a result of implementing the method itself. We are currently investigating the cause of the correlation.

  16. Volatile emissions during storing of green food waste under different aeration conditions.

    Science.gov (United States)

    Agapiou, A; Vamvakari, J P; Andrianopoulos, A; Pappa, A

    2016-05-01

    Controlled field experiments were carried out for monitoring the emissions of three plastic commercial household waste bins, which were adapted for studying the effect of aeration process in the evolved volatiles, during house storing of green food waste for 2 weeks, prior to collection. Three experimental scenarios were examined based on no aeration ("NA," closed commercial waste bin), diffusion-based aeration ("DA," closed commercial waste bin with tiny holes), and enforced aeration ("EA," closed commercial waste bin with tiny holes and enforced aeration). The monitoring of volatile organic compounds (VOCs) emitted from organic household kitchen waste was performed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis. Portable sensors were also used for monitoring selected gases and parameters of environmental, bioprocess, and health interest (e.g., CO2, O2, H2S, CH4, NH3, % RH, waste temperatures). VOC emissions are strongly dependent on the waste material. The most frequent VOCs identified over the storing waste, showing over 50 % appearance in all examined samples, were terpenes (e.g., di-limonene, beta-myrcene, delta-3-carene, alpha-pinene, alpha-terpinolene, linalool, etc.), sulfides (dimethyl disulfide), aromatics (benzene, 1-methyl-2-(2-propenyl)), alkanes (e.g., decane, dodecane), ketones (2-propanone), esters (e.g., acetic acid ethyl ester, acetic acid methyl ester), and alcohols (e.g., 3-cyclohexen-1-ol, 4-methyl-1-(1-methylethyl)). The prominent role of terpenes in the "pre-compost" odor and especially that of di-limonene was highlighted. In all examined scenarios, the emitted volatiles were increased at raised temperatures and later decreased in time. Aeration of waste bins slightly affected the volatilization process resulting in higher profiles of VOCs; uniformity in the composition of VOCs was also noted. Slight modifications of commercial waste bins may favor the initiation of home composting.

  17. POLISHING EFFLUENT FROM A PERCHLORATE-REDUCING ANAEROBIC BIOLOGICAL CONTACTOR

    Science.gov (United States)

    The U.S. Environmental Protection Agency undertook at 3 ½ year pilot-scale biological perchlorate treatment study that included two long (311 and 340 days) examinations of anaerobic effluent polishing. The polishing system consisted of hydrogen peroxide addition and aeration, fo...

  18. Improved Aeration Process - Catalytic Role Of The Iron Oxides In Arsenic Oxidation And Coprecipitation

    DEFF Research Database (Denmark)

    Kowalski, Krysztof; Søgaard, Erik Gydesen

    2013-01-01

    an improved aeration process that can also help in developing better arsenic removal treatment. The results present advantages of arsenic oxidation in an aeration process in the presence of ferrihydrite surface that have been shown to adsorb arsenic simultaneously to its oxidation. The presence...... of precipitated (ferrihydrite surface) and dissolved iron enhanced arsenic oxidation in comparison to solution with absence of precipitated iron in laboratory scale experiments. However, in the pilot scale studies the adsorption of arsenite on ferrihydrite was found to be the main process occurring during...... implementation of the process in the waterworks that are struggling with arsenic related issues....

  19. Effects of Soil Aeration on Sweet Potato Yield and Its Physiological Mechanism

    Institute of Scientific and Technical Information of China (English)

    SHI Chun-yu; WANG Zhen-lin; YU Song-lie

    2002-01-01

    The effects of soil aeration on physiological characters and root tuber yield of Ipomoea batatas (L.) Lam. CV Lushu7 and Xushu18 were studied. The results showed that soil aeration improvement could increase ATP content and ATPase activity in functional leaves and root tubers and ABA content in root tubers.It also accelerated the transportation of 14C-photosynthate from leaves to root tubers and enhanced dry matter distribution in root tubers and thus root tuber yield was significantly raised. The role of ATP, ATPase and ABA in accelerating the transportation of 14C-photosynthate was discussed based on the changes of soluble carbonhydrate content in sweet potato plant.

  20. Protease obtention using Bacillus subtilis 3411 and amaranth seed meal medium at different aeration rates

    Directory of Open Access Journals (Sweden)

    Pastor Maria Delia

    2001-01-01

    Full Text Available The influence of the addition of Amaranthus cruenthus seed meal to the medium, as nutrient and growth factor, on protease production by Bacillus subtilis 3411 was studied. Tests were carried out in a rotary shaker and in mechanically stirred fermenters. The influence of aeration was also evaluated. The addition of amaranth in a concentration of 20 g/L resulted in 400% increase in protease production. Aeration up to 750 r.p.m. and 1 L/L.min had a favorable effect.

  1. The Application of EIS and PIV Methods to the Measurement of Aerated Flow

    Directory of Open Access Journals (Sweden)

    Fejfarová M.

    2013-04-01

    Full Text Available The paper describes measurements in the aerated water medium using modern methods PIV (Particle Image Velocimetry and EIS (Electrical Impedance Spectrometry, which are applied in the Laboratory of Water Management Research (LVV of the Department of Water Structures (UVST at the Faculty of Civil Engineering (FAST of Brno University of Technology (VUT. Measurements of the water medium were carried out for three different aeration intensities at special experimental workplaces. The experiment was focused on the capability of the methods to monitor the air content in the water.

  2. Influence of aeration of Candida albicans during culturing on their surface aggregation in the presence of adhering Streptococcus gordonii

    NARCIS (Netherlands)

    Millsap, KW; van der Mei, HC; Busscher, HJ; Bos, R.R.M.

    1999-01-01

    Candida albicans surfaces are extremely sensitive to changes in growth conditions. In this study, adhesion to glass of aerated and non-aerated C. albicans ATCC 10261 in the presence and absence of adhering Streptococcus gordonii NCTC 7869 was determined in a parallel plate flow chamber. In addition,

  3. Functional linkage between N acquisition strategies and aeration capacities of hydrophytes for efficient oxygen consumption in roots.

    Science.gov (United States)

    Nakamura, Motoka; Nakamura, Takatoshi; Tsuchiya, Takayoshi; Noguchi, Ko

    2013-02-01

    We evaluated the specific strategies of hydrophytes for root O(2) consumption in relation to N acquisition and investigated whether the strategies varied depending on the aeration capacity. Aeration capacity of roots is an important factor for determining hypoxia tolerance in plants. However, some hydrophytes possessing quite different aeration capacities often co-occur in wetlands, suggesting that root O(2) consumption also strongly affects hypoxia tolerance. We cultivated Phragmites australis with high aeration capacity and Zizania latifolia with low aeration capacity in hypoxic conditions with NH(4)(+) or NO(3)(-) treatment and compared the growth, N uptake, N assimilation and root respiration between the two species. In Z. latifolia grown with NH(4)(+) treatment, high N uptake activity and restrained root growth led to sufficient N acquisition and decrease in whole-root respiration rate. These characteristics consequently compensated for the low aeration capacity. In contrast, in P. australis, low N uptake activity was compensated by active root growth, but the whole-root respiration rate was high. This high root respiration rate was allowed by the high aeration capacity. The O(2) consumption-related traits of hydrophyte roots were closely correlated with N acquisition strategies, which consequently led to a compensational relationship with the root aeration capacity. It is likely that this functional linkage plays an important role as a core mechanism in the adaptation of plants to hypoxic soils.

  4. Pathways of nitrobenzene degradation in horizontal subsurface flow constructed wetlands: Effect of intermittent aeration and glucose addition.

    Science.gov (United States)

    Kirui, Wesley K; Wu, Shubiao; Kizito, Simon; Carvalho, Pedro N; Dong, Renjie

    2016-01-15

    Intermittent aeration and addition of glucose were applied to horizontal subsurface flow constructed wetlands in order to investigate the effect on pathways of nitrobenzene (NB) degradation and interactions with microbial nitrogen and sulphur transformations. The experiment was carried out in three phases A, B and C consisting of different NB loading and glucose dosing. For each phase, the effect of aeration was assessed by intermittently aerating one wetland and leaving one unaerated. Regardless of whether or not the wetland was aerated, at an influent NB concentration of 140 mg/L, both wetlands significantly reduced NB to less than 2 mg/L, a reduction efficiency of 98%. However, once the influent NB concentration was increased to 280 mg/L, the aerated wetland had a higher removal performance 82% compared to that of the unaerated wetland 71%. Addition of glucose further intensified the NB removal to 95% in the aerated wetlands and 92% in the unaerated. Aeration of wetlands enhanced NB degradation, but also resulted in higher NB volatilization of 6 mg m(-2) d(-1). The detected high concentration of sulphide 20-60 mg/L in the unaerated wetland gave a strong indication that NB may act as an electron donor to sulphate-reducing bacteria, but this should be further investigated. Aeration positively improved NB removal in constructed wetlands, but resulted in higher NB volatilization. Glucose addition induced co-metabolism to enhance NB degradation.

  5. The effect of aeration position on the spatial distribution and reduction of pollutants in the landfill stabilization process--a pilot scale study.

    Science.gov (United States)

    Chai, Xiaoli; Hao, Yongxia; Shimaoka, Takayuki; Nakayama, Hirofumi; Komiya, Teppei; Zhao, Youcai

    2013-01-01

    Three pilot-scale simulators with different aeration systems were constructed to explore the effects of aeration position on the reduction of pollutants. The simulator with a bottom aeration system successfully distributed oxygen and efficiently inhibited methane production. A close relationship was found between the oxygen distribution and the removal of pollutants, especially that of nitrogen. The transition between nitrification and denitrification in the longitude direction of the simulator with a bottom aeration system contributed to nitrogen removal in aerobic conditions. This process can be defined as a new path for nitrogen removal in addition to simultaneous nitrification and denitrification. The concentration of NH4+ -N total nitrogen and total organic carbon dropped to 3, 78 and 204 mg L(-1), respectively, after 312 days of bottom aeration and to 514, 659 and 828 mg L(-1), respectively, after 312 days of top aeration. These results indicate that the bottom aeration system was more efficient for reducing pollutants than the top aeration system.

  6. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    Science.gov (United States)

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi

    2016-07-01

    Organics and nitrogen removal in four subsurface wastewater infiltration systems (SWISs), named SWIS A (without intermittent aeration and shunt distributing wastewater), SWIS B (with intermittent aeration), SWIS C (with shunt distributing wastewater) and SWIS D (with intermittent aeration and shunt distributing wastewater) was investigated. High average removal rates of 92.3% for COD, 90.2% for NH4-N and 88.1% for TN were achieved simultaneously in SWIS D compared with SWIS A, B and C. The excellent TN removal of SWIS D was due to intermittent aeration provided sufficient oxygen for nitrification in upper matrix and the favorable anoxic or anaerobic environment for denitrification in subsequent matrix, and moreover, shunt distributing wastewater provided sufficient carbon source for denitrification process. The results indicated that intermittent artificial aeration combined with shunt distributing wastewater could achieve high organics and nitrogen removal in SWISs.

  7. Filter quality of pleated filter cartridges.

    Science.gov (United States)

    Chen, Chun-Wan; Huang, Sheng-Hsiu; Chiang, Che-Ming; Hsiao, Ta-Chih; Chen, Chih-Chieh

    2008-04-01

    The performance of dust cartridge filters commonly used in dust masks and in room ventilation depends both on the collection efficiency of the filter material and the pressure drop across the filter. Currently, the optimization of filter design is based only on minimizing the pressure drop at a set velocity chosen by the manufacturer. The collection efficiency, an equally important factor, is rarely considered in the optimization process. In this work, a filter quality factor, which combines the collection efficiency and the pressure drop, is used as the optimization criterion for filter evaluation. Most respirator manufacturers pleat the filter to various extents to increase the filtration area in the limit space within the dust cartridge. Six sizes of filter holders were fabricated to hold just one pleat of filter, simulating six different pleat counts, ranging from 0.5 to 3.33 pleats cm(-1). The possible electrostatic charges on the filter were removed by dipping in isopropyl alcohol, and the air velocity is fixed at 100 cm s(-1). Liquid dicotylphthalate particles generated by a constant output atomizer were used as challenge aerosols to minimize particle loading effects. A scanning mobility particle sizer was used to measure the challenge aerosol number concentrations and size distributions upstream and downstream of the pleated filter. The pressure drop across the filter was monitored by using a calibrated pressure transducer. The results showed that the performance of pleated filters depend not only on the size of the particle but also on the pleat count of the pleated filter. Based on filter quality factor, the optimal pleat count (OPC) is always higher than that based on pressure drop by about 0.3-0.5 pleats cm(-1). For example, the OPC is 2.15 pleats cm(-1) from the standpoint of pressure drop, but for the highest filter quality factor, the pleated filter needed to have a pleat count of 2.65 pleats cm(-1) at particle diameter of 122 nm. From the aspect of

  8. Composing morphological filters

    NARCIS (Netherlands)

    Heijmans, H.J.A.M.

    1995-01-01

    A morphological filter is an operator on a complete lattice which is increasing and idempotent. Two well-known classes of morphological filters are openings and closings. Furthermore, an interesting class of filters, the alternating sequential filters, is obtained if one composes openings and closi

  9. Passive Power Filters

    CERN Document Server

    Künzi, R

    2015-01-01

    Power converters require passive low-pass filters which are capable of reducing voltage ripples effectively. In contrast to signal filters, the components of power filters must carry large currents or withstand large voltages, respectively. In this paper, three different suitable filter struc tures for d.c./d.c. power converters with inductive load are introduced. The formulas needed to calculate the filter components are derived step by step and practical examples are given. The behaviour of the three discussed filters is compared by means of the examples. P ractical aspects for the realization of power filters are also discussed.

  10. Biofiltration of Methane from Ruminants Gas Effluent Using Autoclaved Aerated Concrete as the Carrier Material

    NARCIS (Netherlands)

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Peiren, Nico; De Campeneere, Sam; Ho, Adrian; Boon, Nico

    2015-01-01

    Abstract The performance of Methane-Oxidizing Bacteria (MOB) immobilized on Autoclaved Aerated Concrete (AAC) in a biofilter setup to remove methane from ruminants gas effluent was investigated. Two dairy cows were housed in respiration chambers for two days where the exhaust gas from the chambers w

  11. Gas transfer rates from airlifts used for concurrent aeration, carbon dioxide stripping, and recirculation

    Science.gov (United States)

    Airlifts simplify recirculating aquaculture systems and can potentially reduce capital costs and minimize maintenance issues. Airlifts have the ability to move and aerate water as well as degass the water of any carbon dioxide. This study evaluated the oxygen transfer and carbon dioxide removal abil...

  12. The initial behaviour of freshly etched copper in modertely acid, aerated chloride solutions

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers; Jaskula, M.; Chorkendorff, Ib;

    2002-01-01

    When freshly etched samples of various types of copper were exposed in moderately acid, aerated chloride solutions, two phenomena were observed. First the corrosion potential and the pH of the solution decreased over a shorter time, then the potential increased over a long period (600-1500 min), ...

  13. [Technological characteristics of bioreactor landfill with aeration in the upper layer].

    Science.gov (United States)

    Tian, Ying; Wang, Shen; Xu, Qi-Yong

    2014-11-01

    In order to study the effects of upper-layer aerobic pretreatment in bioreactors on refuse degradation, leachate condition and methane production, two simulated columns were constructed, including traditional anaerobic bioreactor A1 and hybrid bioreactor C1 with aeration pretreatment in the upper layer. Results indicated that A1 was seriously inhibited by the accumulation of volatile fatty acids (VFA) with nearly no methane production and slower settlements. At the end of operations, refuse in A1 only deposited 5.4 cm which was less than half of that in C1. And up to 70 000 mg x L(-1) COD and 30 000 mg x L(-1) VFA could be monitored in the leachate. On the contrary, aerobic pretreatment effectively improved the removal of high VFA concentrations and remarkably accelerated the degradation rate. In bioreactor C1, COD and VFA concentrations were reduced to less than 14000 mg x L(-1) and 8900 mg x L(-1) at the end of the experiment, respectively. And about 61 976 mL methane gases were produced since aeration ceased on day 60 with its methane recovery efficiency rising to over 95%. However, the performance of hybrid bioreactors was still closely related to its operation conditions, such as aeration supply and leachate recirculation. Therefore, in order to guarantee better performance, appropriate aeration and leachate operations need to be provided.

  14. Comparative Study of Nirmalya Solid Waste Treatment by Vermicomposting and Artificial Aeration Composting

    Directory of Open Access Journals (Sweden)

    Pallavi S.Chakole

    2014-08-01

    Full Text Available Temple waste normally contains floral offering, leaves and milk product i.e. “Abishek waste water”, and this solid waste management is one of the important issues in the world, because of shortage ofdumping sites and strict environmental legislation. Now days ‘Nirmalyasolid waste’ is generated in large quantity due toincreased in population are commonly treated using different types of bins by the method of composting or vermicomposting. Vermicomposting of solid waste can be done by using different types of earthworms providing natural and artificial aeration along with mixture of cow dung and soil, artificial aeration is carried out by providing diffused aerators or perforated pipes. The parameters like C/N ratio, temperature, moisture contain are carried out. The main objective of this study is to minimize the problem of solid waste management by treating nirmalya solid waste by vermicomposting and suggesting that which method gives good quality of compost at short interval of time comparing artificial and natural aeration composting.

  15. Evaluation of cost-effective aeration technology solutions to address total trihalomethane (TTHM) compliance

    Science.gov (United States)

    The primary objective of this project was to evaluate cost-effective aeration technology solutions to address TTHM compliance at a water treatment plant clearwell. The project team worked closely with EPA Region 6 and the EPA Office of Research and Development (ORD) to identify a...

  16. Embedded system in Arduino platform with Fuzzy control to support the grain aeration decision

    Directory of Open Access Journals (Sweden)

    Albino Szesz Junior

    Full Text Available ABSTRACT: Aeration is currently the most commonly used technique to improve the drying and storage of grain, depending on temperature and water content of the grain, as of the temperature and relative humidity of the outside air. In order to monitor temperature and humidity of the grain mass, it is possible to have a network of sensors in the cells of both internal and external storage. Use of artificial intelligence through Fuzzy theory, has been used since the 60s and enables their application on various forms. Thus, it is observed that the aeration of grain in function of representing a system of controlled environment can be studied in relation to the application of this theory. Therefore, the aim of this paper is to present an embedded Fuzzy control system based on the mathematical model of CRUZ et al. (2002 and applied to the Arduino platform, for decision support in aeration of grain. For this, an embedded Arduino system was developed, which received the environmental values of temperature and humidity to then be processed in a Fuzzy controller and return the output as a recommendation to control the aeration process rationally. Comparing the results obtained from the graph presented by LASSERAN (1981 it was observed that the system is effective.

  17. Effect of agitation and aeration on the citric acid production by Yarrowia lipolytica grown on glycerol.

    Science.gov (United States)

    Rywińska, Anita; Musiał, Izabela; Rymowicz, Waldemar; Zarowska, Barbara; Boruczkowski, Tomasz

    2012-01-01

    The effects of agitation rates from 400 to 900 rpm and aeration rates ranging from 0.18 to 0.6 vvm on biomass and citric acid production on glycerol media by acetate-negative mutants of Yarrowia lipolytica, Wratislavia 1.31 and Wratislavia AWG7, in batch culture were studied. The agitation rates of 800 and 900 rpm (at a constant aeration rate of 0.36 vvm) and aeration rates within the range of 0.24-0.48 vvm (at a constant agitation rate of 800 rpm), which generated dissolved oxygen concentration (DO) higher than 40%, were found the best for citric acid biosynthesis from glycerol. An increase in agitation rate (higher than 800 rpm) and aeration rate (higher than 0.36 vvm) had no impact on DO and citric acid production. The highest citric acid concentration (92.8 g/L) and yield (0.63 g/g) were obtained with Wratislavia 1.31 strain at 0.24 vvm. The highest volumetric citric acid production rate (1.15 g/Lh) and specific citric acid production rate (0.071 g/gh) were reached at 0.48 vvm.

  18. Epstein-Plesset theory based measurements of concentration of nitrogen gases dissolved in aerated water

    Science.gov (United States)

    Sasaki, Masashi; Yamashita, Tatsuya; Ando, Keita

    2016-11-01

    Microbubble aeration is used to dissolved gases into water and is an important technique in agriculture and industry. We can measure concentration of dissolved oxygen (DO) in aerated water by commercial DO meters. However, there do not exist commercially available techniques to measure concentration to dissolved nitrogen (DN). In the present study, we propose the method to measure DN in aerated water with the aid of Epstein-Plesset-type analysis. Gas-supersaturated tap water is produced by applying aeration with micro-sized air bubbles and is then stored in a glass container open to the atmosphere. Diffusion-driven growth of bubbles nucleated at the container surface is recorded with a video camera. The bubble growth rate is compare to the extended Epstein-Plesset theory that models mass transfer of both DO and DN into the surface-attached bubbles base on the diffusion equation. Given the DO measurements, we can obtain the DN level by fitting in the comparison.

  19. Processes to improve energy efficiency during pumping and aeration of recirculating water in circular tank systems

    Science.gov (United States)

    Conventional gas transfer technologies for aquaculture systems occupy a large amount of space, require considerable capital investment, and can contribute to high electricity demand. In addition, diffused aeration in a circular tank can interfere with the hydrodynamics of water rotation and the spee...

  20. A STUDY OF THE DISCHARGE OF COHESIVE POWDERS UNDER SIMULTANEOUS AERATION AND VIBRATION

    NARCIS (Netherlands)

    Marring, E.; Hoffmann, A.C; Janssen, L.P.B.M.

    1995-01-01

    The influence of applying simultaneous aeration and vibration on the discharge of cohesive powders from a laboratory scale cylindrical silo has been studied experimentally. The powders investigated were batches of potato starch powder of different moisture contents and therefore different degrees of

  1. Effects of overlying water aeration on phosphorus fractions and alkaline phosphatase activity in surface sediment

    Institute of Scientific and Technical Information of China (English)

    Jianjun Chen; Shaoyong Lu; Yikun Zhao; Wei Wang; Minsheng Huang

    2011-01-01

    Microbial activity may influence phosphorus (P) deposit and release at the water sediment interface.The properties of DO (dissolved oxygen), pH, P fractions (TP, Ca-P, Fe-P, OP, IP), and APA (alkaline phosphatase activity) at the water sediment interface were measured to investigate microbial activity variations in surface sediment under conditions of two-month intermittent aeration in overlying water.Results showed that DO and TP of overlying water increased rapidly in the first week and then decreased gradually after 15 day of intermittent aeration.Microorganism metabolism in surface sediment increased pH and decreased DO and TP in the overlying water.After two-month intermittent aeration, APA and OP from surface sediment (0-2 crm) were both significantly higher than those from bottom sediment (6-8 cm) (p < 0.05), and surface sediment Fe-P was transferred to OP during the course of microorganism reproduction on the surface sediment.These results suggest that microbial activity and microorganism biomass from the surface sediment were higher than those from bottom sediment afar two-month intermittent aeration in the overlying water.

  2. Effects of Aeration on Root Physiology and Nitrogen Metabolism in Rice

    Institute of Scientific and Technical Information of China (English)

    XU Chun-mei; WANG Dan-ying; CHEN Song; CHEN Li-ping; ZHANG Xiu-fu

    2013-01-01

    In order to clarify the effects of aeration on root nitrogen metabolism in rice seedlings,rice cultivars Guodao 6 (indica) and Xiushui 09 (japonica) were investigated for root growth,the activities of glutamine synthetase (GS),glutamic acid-pyruvic acid transaminase (GPT) and glutamic acid oxaloacetate transaminase (GOT),the nitrate (NO3-N) concertration,the contents of free amino acids and soluble sugar in root under hydroponics with continuous aeration treatment.The results showed that rice seedlings grown in oxygenation solutions had higher root dry matter,longer root length,stronger root activity and larger root absorption area compared with the control.In addition,the contents of soluble sugar,root vigor and the activities of GS,GOT and GPT in the aeration solutions were higher than those in the control.The results also indicated that the activities of enzymes involved in root nitrogen metabolism of Xiushui 09 were enhanced by aeration,however,there was no significant influence on root nitrogen metabolism of Guodao 6,which suggested that effect of oxygenation on rice root nitrogen metabolism might be genotype-specific.

  3. Effect of the aerated structure on selected properties of freeze-dried hydrocolloid gels

    Science.gov (United States)

    Ciurzyńska, Agnieszka; Lenart, Andrzej

    2016-01-01

    The ability to create diverse structures and studies on the effect of the aerated structure on selected properties with the use of freeze-dried gels may provide knowledge about the properties of dried foods. Such gels can be a basis for obtaining innovative food products. For the gel preparation, 3 types of hydrocolloids were used: low-methoxyl pectin, a mixture of xanthan gum and locust-bean gum, and a mixture of xanthan gum and guar gum. Gels were aerated for 3 and 7 min, frozen at a temperature of -45°C 2 h-1, and freeze-dried at a temperature of 30°C. For the samples obtained, structure, porosity, shrinkage, rehydration, and colour were investigated. It was shown that the type of the hydrocolloid and aeration time influence the structure of freeze-dried gels, which determines such properties of samples as porosity, shrinkage, density, rehydration, and colour. The bigger pores of low-methoxyl pectin gels undergo rehydration in the highest degree. The delicate and aerated structure of gels with the mixture of xanthan gum and locust-bean gum was damaged during freeze-drying and shrinkage exhibited the highest value. Small pores of samples with the mixture of xanthan gum and guar gum were responsible for the lower rehydration properties, but the highest porosity value contributed to the highest lightness value.

  4. Production of Candida utilis Biomass and Intracellular Protein Content: Effect of Agitation Speed and Aeration Rate

    Directory of Open Access Journals (Sweden)

    Rosma, A.

    2006-01-01

    Full Text Available The effects of agitation speed and aeration rate on the Candida utilis biomass and the intracellular protein content were investigated in this study. C. utilis inoculum of 10^6 cells/mL (7.8 % v/v was cultured in 1.5 L pineapple waste medium (3 % Brix in a 2-L fermentor for 30 h at 30 °C. Agitation speed and aeration rate have significant effects on the dissolved oxygen concentration, which in turn affect the cell growth and the intracellular protein content. The agitation speed of 100, 300, 500, 700 and 900 rpm was employed. The highest yield of protein content (1.2 g/L media and total biomass (7.8 g/L media were resulted from yeast cultivation with agitation speed of 900 rpm. Thus, the effects of aeration rate (0.5, 1.0, 2.0 and 3.0 L/min were studied at agitation speed of 900 rpm. A maximum yield of protein content (1.6 g/L media and biomass (9.5 g/L media were attained at aeration rate of 2.0 L/min.

  5. Mecoprop (MCPP) removal in full-scale rapid sand filters at a groundwater-based waterworks

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Arvin, Erik; Corfitzen, Charlotte B.;

    2014-01-01

    Contamination by the herbicide mecoprop (MCPP) was detected in groundwater abstraction wells at Kerteminde Waterworks in concentrations up to 0.08μg/L. MCPP was removed to below detection limit in a simple treatment line where anaerobic groundwater was aerated and subsequently filtered by primary...... filters, MCPP concentration decreased from 0.037μg/L to below the detection limit of 0.01μg/L. MCPP was removed continuously at different filter depths (0.80m).Additionally, biodegradation, mineralisation and adsorption were investigated in the laboratory in order to elucidate removal mechanisms.......It was concluded that MCPP was removed in secondary rapid sand filters at Kerteminde Waterworks, to which both adsorption and microbial degradation contributed....

  6. Impact of intermittent aerations on leachate quality and greenhouse gas reduction in the aerobic-anaerobic landfill method.

    Science.gov (United States)

    Nag, Mitali; Shimaoka, Takayuki; Komiya, Teppei

    2016-09-01

    The aerobic-anaerobic landfill method (AALM) is a novel approach in solid waste management that could shorten the landfill post-closure period and minimize the environmental loads. In this study, the aerobic-anaerobic landfill method was evaluated by using intermittent aeration. In addition, the nitrification-denitrification process was assessed as a means of reducing the emission of greenhouse gases (GHGs) and improving the leachate quality during the degradation of the organic solid waste. The leachate quality and the gas composition in each of the reactors were measured during the experimental period (408days). The aeration process entailed the injection of air into plexiglass cylinders (200cm height×10 cm diameter), filled with fresh organic solid waste collected from a composting plant. Different aeration routines were applied, namely, continuous aeration (aerobic reactor A), aeration for three days/week (aerobic-anaerobic reactor B), aeration for 6h/day (aerobic-anaerobic reactor C), and no aeration (non-aerated reactor D). It was found that aerobic reactor A produced the best results in terms of reduction of GHGs and improvement of the leachate quality. The aerobic-anaerobic reactor C was found to be more effective than reactor B in respect of both the emission of GHGs and the leachate quality; moreover, compared with aerobic reactor A, energy costs were reduced by operating this reactor. The transition period phenomenon was investigated during an intensive seven-day experiment conducted on the discharged leachate obtained from aerobic-anaerobic reactors B and C. The experiment concerned the differences in the composition of the gas during the aeration and the non-aeration periods. It was found that the transition period between the aeration and non-aeration cycles, which followed the simultaneous nitrification-denitrification had a considerable effect on the leachate quality of both the reactors. The results indicated that AALM has the potential to reduce

  7. Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Suyun [Department of Environmental and Low-Carbon Science, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai (China); Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong); Selvam, Ammaiyappan [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong); Wong, Jonathan W.C., E-mail: jwcwong@hkbu.edu.hk [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region (Hong Kong)

    2014-02-15

    Highlights: • Effect of micro-aeration on acidogenesis and hydrolysis of food waste was investigated. • Micro-aeration at 258 L-air/kg TS/d increased the VFAs production 3-fold. • High aeration leads to loss of substrate through microbial biomass and respiration. • Optimum aeration increased methane recovery while high aeration intensity reduced methane yield. - Abstract: Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35 °C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21–27% and 38–64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH{sub 4}/g VS{sub added} in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO{sub 2} respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.

  8. Allocation of supplementary aeration stations in the Chicago waterway system for dissolved oxygen improvement.

    Science.gov (United States)

    Alp, Emre; Melching, Charles S

    2011-06-01

    The Chicago Waterway System (CWS), used mainly for commercial and recreational navigation and for urban drainage, is a 122.8 km branching network of navigable waterways controlled by hydraulic structures. The CWS receives pollutant loads from 3 of the largest wastewater treatment plants in the world, nearly 240 gravity Combined Sewer Overflows (CSO), 3 CSO pumping stations, direct diversions from Lake Michigan, and eleven tributary streams or drainage areas. Even though treatment plant effluent concentrations meet the applicable standards and most reaches of the CWS meet the applicable water quality standards, Dissolved Oxygen (DO) standards are not met in the CWS during some periods. A Use Attainability Analysis was initiated to evaluate what water quality standards can be achieved in the CWS. The UAA team identified several DO improvement alternatives including new supplementary aeration stations. Because of the dynamic nature of the CWS, the DUFLOW model that is capable of simulating hydraulics and water quality processes under unsteady-flow conditions was used to evaluate the effectiveness of new supplementary aeration stations. This paper details the use of the DUFLOW model to size and locate supplementary aeration stations. In order to determine the size and location of supplemental aeration stations, 90% compliance with a 5 mg/l DO standard was used as a planning target. The simulations showed that a total of four new supplementary aeration stations with oxygen supply capacities ranging from 30 to 80 g/s would be sufficient to meet the proposed target DO concentration for the North Branch and South Branch of the Chicago River. There are several aeration technologies, two of which are already being used in the CWS, available and the UAA team determined that the total capital costs of the alternatives range from $35.5 to $89.9 million with annual operations and maintenance costs ranging from $554,000 to $2.14 million. Supplemental aeration stations have been

  9. Biodegradation of beet molasses vinasse by a mixed culture of micro organisms: Effect of aeration conditions and pH control

    Institute of Scientific and Technical Information of China (English)

    Krzysztof Lutoslawski; Agnieszka Ryznar-Luty; Edmund Cibis; Malgorzata Krzywonos; Tadeusz Mi(s)kiewicz

    2011-01-01

    The effect of aeration conditions and pH control on the progress and efficiency of beet molasses vinasse biodegradation was investigated during four batch processes at 38℃ with the mixed microbial culture composed of Bifidobacterium,Lactobacillus,Lactococcus,Streptococcus,Bacillus,Rhodopseudomonas,and Saccharomyces.The four processes were carried out in a shake flask with no pH control,an aerobic bioreactor without mixing with no pH control,and a stirred-tank reactor (STR) with aeration with and without pH control,respectively.All experiments were started with an initial pH 8.0.The highest efficiency of biodegradation was achieved through the processes conducted in the STR,where betaine (an organic pollutant occurring in beet molasses in very large quantities) was completely degraded by the microorganisms.The process with no pH control carried out in the STR produced the highest reduction in the following pollution measures:organic matter expressed as chemical oxygen demand determined by the dichromatic method + theoretical COD of betaine (CODsum,85.5%),total organic carbon (TOC,78.8%) and five-day biological oxygen demand (BOD5,98.6%).The process conditions applied in the shake flask experiments,as well as those used in the aerobic bioreactor without mixing,failed to provide complete betaine assimilation.As a consequence,reduction in CODwum,TOC and BOD5 was approximately half that obtained with STR.

  10. Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat

    Directory of Open Access Journals (Sweden)

    Samuel S. Liu

    2016-06-01

    Full Text Available A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner, the Indian meal moth Tribolium castaneum (Herbst, the red flour beetle, Cryptolestes ferrugineus (Stephens, the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel, the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L., the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America.

  11. Lipid accumulation and CO2 utilization of Nannochloropsis oculata in response to CO2 aeration.

    Science.gov (United States)

    Chiu, Sheng-Yi; Kao, Chien-Ya; Tsai, Ming-Ta; Ong, Seow-Chin; Chen, Chiun-Hsun; Lin, Chih-Sheng

    2009-01-01

    In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO(2) aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO(2), the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L(-1)d(-1) with 2% CO(2) aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO(2), the biomass and lipid productivity could reach to 0.372 and 0.084 g L(-1)d(-1), respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L(-1)d(-1) in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L(-1)d(-1) in three-day replacement (three fifth broth was replaced every 3d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO(2) and operated by one-day replacement.

  12. [Effect of Aeration Strategies on Emissions of Nitrogenous Gases and Methane During Sludge Bio-Drying].

    Science.gov (United States)

    Qi, Lu; Wei, Yuan-song; Zhang, Jun-ya; Zhao, Chen-yang; Cai, Xing; Zhang, Yuan-li; Shao, Chun-yan; Li, Hong-mei

    2016-01-15

    The data on nitrogen gas (NH3, N2O, NO) emissions during sludge bio-drying process in China is scarce, especially NO due to its unstable chemical property. In this study, effect of two aeration modes on emissions of methane and nitrogenous gas was compared during the continuous aerated turning pile sludge bio-drying process at full scale. In these two aeration strategies, the one currently used in the plant was set as the control, and the other was set as the test in which the aeration was used for oxygen supply, pile temperature control, and moisture removal in the start-up, middle and final stages, respectively. The results showed that the aeration strategy used in the test could not only obviously accelerate the rate of sludge drying (the moisture contents of the test and the control were 36.6% and 42% on day 11) , but also had a better drying performance (the final moisture contents of the test and the control were 33.6% and 37.6%, respectively) and decreased the ammonia cumulative emission by 5%, (ammonia cumulative emission of the test and the control were 208 mg x m(-3) and 219.8 mg x m(-3), respectively). Though a lower accumulated emission (eCO2) of greenhouse gas in the test at 3.61 kg x t(-1) was observed than that of the control (3.73 kg x t(-1) dry weight) , the cumulative emission of NO in the test at 1.9 g x m(-2) was 15. 9% higher than that of the control (1.6 g x m(-2)).

  13. A New Control and Design of PEM Fuel Cell System Powered Diffused Air Aeration System

    Directory of Open Access Journals (Sweden)

    Ninet M. Ahmed

    2012-06-01

    Full Text Available The goal of aquaculture ponds is to maximize production and profits while holding labor and management efforts to the minimum. Poor water quality in most ponds causes risk of fish kills, disease outbreaks which lead to minimization of pond production. Dissolved Oxygen (DO is considered to be among the most important water quality parameters in fish culture. Fish ponds in aquaculture farms are usually located in remote areas where grid lines are at far distance. Aeration of ponds is required to prevent mortality and to intensify production, especially when feeding is practical, and in warm regions. To increase pond production it is necessary to control dissolved oxygen. Aeration offers the most immediate and practical solution to water quality problems encountered at higher stocking and feeding rates. Many units of aeration system are electrical units so using a continuous, high reliability, affordable, and environmentally friendly power sources is necessary. Fuel cells have become one of the major areas of research in the academia and the industry. Aeration of water by using PEM fuel cell power is not only a new application of the renewable energy, but also, it provides an affordable method to promote biodiversity in stagnant ponds and lakes. This paper presents a new design and control of PEM fuel cell powered a diffused air aeration system for a shrimp farm in Mersa Matruh in Egypt. Also Artificial intelligence (AI control techniques are used to control the fuel cell output power by controlling its input gases flow rate. Moreover the mathematical modeling and simulation of PEM fuel cell is introduced. A comparative study is applied between the performance of fuzzy logic controller (FLC and neural network controller (NNC. The results show the effectiveness of NNC over FLC.

  14. Spatiotemporal Aeration and Lung Injury Patterns Are Influenced by the First Inflation Strategy at Birth.

    Science.gov (United States)

    Tingay, David G; Rajapaksa, Anushi; Zonneveld, C Elroy; Black, Don; Perkins, Elizabeth J; Adler, Andy; Grychtol, Bartłomiej; Lavizzari, Anna; Frerichs, Inéz; Zahra, Valerie A; Davis, Peter G

    2016-02-01

    Ineffective aeration during the first inflations at birth creates regional aeration and ventilation defects, initiating injurious pathways. This study aimed to compare a sustained first inflation at birth or dynamic end-expiratory supported recruitment during tidal inflations against ventilation without intentional recruitment on gas exchange, lung mechanics, spatiotemporal regional aeration and tidal ventilation, and regional lung injury in preterm lambs. Lambs (127 ± 2 d gestation), instrumented at birth, were ventilated for 60 minutes from birth with either lung-protective positive pressure ventilation (control) or as per control after either an initial 30 seconds of 40 cm H2O sustained inflation (SI) or an initial stepwise end-expiratory pressure recruitment maneuver during tidal inflations (duration 180 s; open lung ventilation [OLV]). At study completion, molecular markers of lung injury were analyzed. The initial use of an OLV maneuver, but not SI, at birth resulted in improved lung compliance, oxygenation, end-expiratory lung volume, and reduced ventilatory needs compared with control, persisting throughout the study. These changes were due to more uniform inter- and intrasubject gravity-dependent spatiotemporal patterns of aeration (measured using electrical impedance tomography). Spatial distribution of tidal ventilation was more stable after either recruitment maneuver. All strategies caused regional lung injury patterns that mirrored associated regional volume states. Irrespective of strategy, spatiotemporal volume loss was consistently associated with up-regulation of early growth response-1 expression. Our results show that mechanical and molecular consequences of lung aeration at birth are not simply related to rapidity of fluid clearance; they are also related to spatiotemporal pressure-volume interactions within the lung during inflation and deflation.

  15. Combination of Methoprene and Controlled Aeration to Manage Insects in Stored Wheat.

    Science.gov (United States)

    Liu, Samuel S; Arthur, Frank H; VanGundy, Douglas; Phillips, Thomas W

    2016-06-17

    A commercial formulation of the insect growth regulator methoprene was applied to wheat stored in small bins either alone or in combination with controlled aeration of the bins, to lower grain temperature for insect pest management of stored wheat. Grain temperatures were monitored and modified by a computer-controlled thermocouple system that also activated the aeration system at programmed set-points to move cool ambient air through the grain mass to lower grain temperature. Results from sampling insect populations in experimental storage bins along with laboratory mortality bioassays of insects placed on wheat taken from the bins over the course of the storage period showed that methoprene was very effective in controlling infestation by the externally-feeding stored grain insects Plodia interpunctella (Hübner), the Indian meal moth Tribolium castaneum (Herbst), the red flour beetle, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, and also for the internal-feeding pest Rhyzopertha dominica( Fauvel), the lesser grain borer. Methoprene did not give good control of the internal-feeding pest Sitophilus oryzae (L.), the rice weevil. Aeration alone was somewhat effective in suppressing insect population development, while methoprene alone or when combined with aeration greatly enhanced insect control. Commercial grain grading for industry quality standards at the end of the storage period confirmed the impact of insect suppression on maintaining high quality of the stored wheat. This field experiment shows that methoprene combined with aeration to cool grain can be effective for pest management of stored wheat in the southern plains of the United States of America.

  16. Ammonia transformation in a biotrickling air filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Nielsen, Marie Louise; Andersen, Mathias;

    2007-01-01

    measurements and model was obtained by using conventional substrate and inhibition kinetics of ammonium and nitrite oxidizing bacteria. Highest rates of ammonia removal were observed in the central section of the filter. Near the air outlet and water inlet the process was ammonia limited, while high nitrous...... acid concentrations almost excluded any biological activity near the air inlet and water outlet. Nitrous acid inhibition also stabilized pH at 6.5-7 all through the filter. Being sensitive to both ammonia and nitrous acid the nitrite oxidation process occurred mainly in the filter sections near the air...... outlet / water inlet, and only 8% of the nitrite was turned into nitrate. Water supply only exceeded evaporation by 20% but modelling indicated that additional watering would have limited effect on filter efficiency. The filter was also robust to varying loading, as a 4-fold increase in ammonia inlet...

  17. Hydraulic characteristics of converse curvature section and aerator in high-head and large discharge spillway tunnel

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The hydraulic characteristics and cavitation erosion near the converse curvature section in the high-head and large discharge spillway tunnel have been important issues of concern to the hydropower project.In this paper,the evolutions of hydraulic elements such as pressure,flow velocity,wall shear stress,etc.in the converse curvature section are analyzed and the impacts of bottom aerator on hydraulic characteristics are discussed,with the commercial software FLUENT6.3 as a platform and combining the k-model and VOF method.The flow pattern in the converse curvature section of spillway tunnel is given by the three-dimensional numerical simulation.It indicates that the pressure changes rapidly with great pressure gradient from the beginning to the end of the curve.It also shows that the shear stress on side wall just downstream the end of the converse curvature curve is still increasing;the aeration cavity formed downstream the bottom aerator may cause the side wall pressure decreased to worsen the cavitation characteristics near the side wall.By means of the physical model experiment,the three-dimensional aerator composed of side wall baffling aerator and bottom aerator is studied,the baffling aerator suitable for the water flow conditions with water depth of 6.0 to 8.0 m and flow velocity of 35 to 50 m/s is proposed.

  18. Influence of aeration modes on leachate characteristic of landfills that adopt the aerobic-anaerobic landfill method.

    Science.gov (United States)

    Wu, Chuanfu; Shimaoka, Takayuki; Nakayama, Hirofumi; Komiya, Teppei; Chai, Xiaoli; Hao, Yongxia

    2014-01-01

    As far as the optimal design, operation, and field application of the Aerobic-Anaerobic Landfill Method (AALM) are concerned, it is very important to understand how aeration modes (different combinations of aeration depth and air injection rate) affect the biodegradation of organic carbon and the transformation of nitrogen in landfill solid waste. Pilot-scale lysimeter experiments were carried out under different aeration modes to obtain detailed information regarding the influence of aeration modes on leachate characteristics. Results from these lysimeter experiments revealed that aeration at the bottom layer was the most effective for decomposition of organic carbon when compared with aeration at the surface or middle layers. Moreover, the air injection rate led to different nitrogen transformation patterns, unlike the lesser influence it has on organic carbon decomposition. Effective simultaneous nitrification and denitrification were observed for the aeration mode with a higher air injection rate (=1.0 L/min). On the other hand, the phenomenon of sequenced nitrification and denitrification could be observed when a low air injection rate (=0.5L/min.) was employed. Finally, it is concluded that, for AALM, air injection with a higher air injection rate at the deepest layer near the leachate collection pipe tends to accelerate the stabilization of landfill waste as defined in terms of the enhancement of denitrification as well as organic carbon decomposition.

  19. Removal of organic pollutants from oak leachate in pilot scale wetland systems: How efficient are aeration and vegetation treatments?

    Science.gov (United States)

    Svensson, Henric; Ekstam, Börje; Marques, Marcia; Hogland, William

    2015-11-01

    This study investigated the effects of aeration and/or vegetation in experimental constructed wetlands (CWs) as mesocosms on the removal of pollutants in oak wood leachate. Twelve outdoor wetland mesocosms, with randomized replicated treatment combinations of vegetation (Phragmites australis) and aeration was monitored during the second and third year after construction. The investigation included control tanks with no aeration and no vegetation. The parameters monitored were polyphenols (PPs), chemical oxygen demand (COD) and water colour. The reduction of COD after 28 days was approx. 50% and more than 50% of PPs, whereas only 40% of the water colour was removed. Aeration increased the effect of both COD and PP removal. The vegetation treatment had a small but significant effect on removal of COD. The vegetation + aeration treatment, as well as aeration alone, increased the removal efficiency of COD from 9.5 g m(-3) d(-1) in the control to 11 g m(-3) d(-1). The results suggest that CWs can be used to treat stormwater contaminated by oak wood leachate. Further, it is suggested that the main processes for removal of pollutants in the leachate occur in the open-water habitat and that the hydraulic retention time is more important for removal than aeration and vegetation related processes.

  20. Intensified organics and nitrogen removal in the intermittent-aerated constructed wetland using a novel sludge-ceramsite as substrate.

    Science.gov (United States)

    Wu, Haiming; Fan, Jinlin; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Liang, Shuang; Lv, Jialong; Lu, Shaoyong; Wu, Weizhong; Wu, Suqing

    2016-06-01

    In this study, a novel sludge-ceramsite was applied as main substrate in intermittent-aerated subsurface flow constructed wetlands (SSF CWs) for treating decentralized domestic wastewater, and intensified organics and nitrogen removal in different SSF CWs (with and without intermittent aeration, with and without sludge-ceramsite substrate) were evaluated. High removal of 97.2% COD, 98.9% NH4(+)-N and 85.8% TN were obtained simultaneously in the intermittent-aerated CW system using sludge-ceramsite substrate compared with non-aerated CWs. Moreover, results from fluorescence in situ hybridization (FISH) analysis revealed that the growth of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the intermittent-aerated CW system with sludge-ceramsite substrate was enhanced, thus indicating that the application of intermittent aeration and sludge-ceramsite plays an important role in nitrogen transformations. These results suggest that a combination of intermittent aeration and sludge-ceramsite substrate is reliable to enhance the treatment performance in SSF CWs.

  1. Oxygen demand for the stabilization of the organic fraction of municipal solid waste in passively aerated bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Kasinski, Slawomir, E-mail: slawomir.kasinski@uwm.edu.pl; Wojnowska-Baryla, Irena

    2014-02-15

    Highlights: • The use of an passively aerated reactor enables effective stabilization of OFMSW. • Convective air flow does not inhibit the aerobic stabilization of waste. • The use of an passively aerated reactor reduces the heat loss due to convection. • The volume of supplied air exceeds 1.7–2.88 times the microorganisms demand. - Abstract: Conventional aerobic waste treatment technologies require the use of aeration devices that actively transport air through the stabilized waste mass, which greatly increases operating costs. In addition, improperly operated active aeration systems, may have the adverse effect of cooling the stabilized biomass. Because active aeration can be a limiting factor for the stabilization process, passive aeration can be equally effective and less expensive. Unfortunately, there are few reports documenting the use of passive aeration systems in municipal waste stabilization. There have been doubts raised as to whether a passive aeration system provides enough oxygen to the organic matter mineralization processes. In this paper, the effectiveness of aeration during aerobic stabilization of four different organic fractions of municipal waste in a reactor with an integrated passive ventilation system and leachate recirculation was analyzed. For the study, four fractions separated by a rotary screen were chosen. Despite the high temperatures in the reactor, the air flow rate was below 0.016 m{sup 3}/h. Using Darcy’s equation, theoretical values of the air flow rate were estimated, depending on the intensity of microbial metabolism and the amount of oxygen required for the oxidation of organic compounds. Calculations showed that the volume of supplied air exceeded the microorganisms demand for oxidation and endogenous activity by 1.7–2.88-fold.

  2. Method of securing filter elements

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Erik P.; Haslam, Jeffery L.; Mitchell, Mark A.

    2016-10-04

    A filter securing system including a filter unit body housing; at least one tubular filter element positioned in the filter unit body housing, the tubular filter element having a closed top and an open bottom; a dimple in either the filter unit body housing or the top of the tubular filter element; and a socket in either the filter unit body housing or the top of the tubular filter element that receives the dimple in either the filter unit body housing or the top of the tubular filter element to secure the tubular filter element to the filter unit body housing.

  3. Dormancy and Recovery Testing for Biological Wastewater Processors

    Science.gov (United States)

    Hummerick, Mary F.; Coutts, Janelle L.; Lunn, Griffin M.; Spencer, LaShelle; Khodadad, Christina L.; Birmele, Michele N.; Frances, Someliz; Wheeler, Raymond

    2015-01-01

    Resource recovery and recycling waste streams to usable water via biological water processors is a plausible component of an integrated water purification system. Biological processing as a pretreatment can reduce the load of organic carbon and nitrogen compounds entering physiochemical systems downstream. Aerated hollow fiber membrane bioreactors, have been proposed and studied for a number of years as an approach for treating wastewater streams for space exploration.

  4. 曝气生物滤池技术%Elementary Introduction on the Techniques of Aeration Bio-filter Tank

    Institute of Scientific and Technical Information of China (English)

    李菲; 卢佳

    2006-01-01

    介绍了曝气生物滤池的原理及特点,并对曝气生物滤池的主要形式进行了总结和描述.从去除有机物、SS、硝化、反硝化等方面阐述了曝气生物滤池的主要功能,并就曝气生物滤池的设计和运行提出了作者的观点.

  5. Structure formation of aerated concrete containing waste coal combustion products generated in the thermal vortex power units

    Science.gov (United States)

    Ivanov, A. I.; Stolboushkin, A. Yu; Temlyanstev, M. V.; Syromyasov, V. A.; Fomina, O. A.

    2016-10-01

    The results of fly ash research, generated in the process of waste coal combustion in the thermal vortex power units and used as an aggregate in aerated concrete, are provided. It is established that fly ash can be used in the production of cement or concrete with low loss on ignition (LOI). The permitted value of LOI in fly ash, affecting the structure formation and operational properties of aerated concrete, are defined. During non-autoclaved hardening of aerated concrete with fly ash aggregate and LOI not higher than 2%, the formation of acicular crystals of ettringite, reinforcing interporous partitions, takes place.

  6. Investigation of pure- and aerated-liquid jets using ultra-fast X-ray phase contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Kuo-Cheng, E-mail: Kuo-Cheng.Lin@wpafb.af.mil [Taitech, Inc., Beavercreek, OH 45430 (United States); Rajnicek, Christopher; McCall, Jonathan; Carter, Campbell [Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433 (United States); Fezzaa, Kamel [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2011-09-01

    Pure- and aerated-liquid jets were observed using the ultra-fast X-ray phase contrast imaging technique. Highly convoluted wrinkle structures were seen on the column surface of a turbulent pure-liquid jet, gas bubbles were discovered inside droplets and ligaments of aerated-liquid sprays, and apparently homogenous two-phase mixtures were observed inside the aerated-liquid injector. The major limitation of this X-ray technique lies in its line-of-sight nature, which can create overlapped objects/interfaces on the X-ray images.

  7. 活性炭滤池中微生物特征及其对溶解性有机碳的去除作用%Characteristics of biomass in biological activated carbon(BAC)filters and its contribution to DOC removal

    Institute of Scientific and Technical Information of China (English)

    张春雷; 王东升; 樊康平; 顾军农; 李涛

    2009-01-01

    采用异养菌总数计数(HPC)法检测了北京地区J水厂活性炭滤池中微生物量,并分析了活性炭滤池进出水中有机物的组成、活性炭的吸附作用及微生物作用对溶解性有机碳(DOC)去除的贡献率.结果表明,不同炭龄、不同运行周期活性炭滤池中的微生物量有显著的差异.由于溶解性可生物降解有机碳(BDOC)占溶解性有机碳(DOC)的比例较小,且受微生物数量、活性等因素的影响,微生物对DOC的去除效果极为有限,在1.5年和5年炭龄活性炭滤池中对DOC的去除率仅占总去除率的18.8%和26.4%.此外,微生物对较为敏感的嗅味物质2-MIB和geosmin去除作用也不显著,去除率在15%以下(初始浓度为100ng·L~(-1));在使用5年活性炭滤池中,微生物对2-MIB和geosmin去除率为12%和14%,分别占总去除率的32%和29%.因此,北京地区地表水净水厂活性炭滤池中微生物对有机物控制的贡献率较低,对DOC的去除主要以活性炭的吸附为主.%Heterotrophic plate count ( HPC ) determination is applied to measure the biomass on the carbon used in the biological activated carbon ( BAC ) filter in a water treatment plant in Beijing. The effect of the DOC component in the filtered water, the adsorption of active carbon, the biological activity, and their contribution to DOC removal is analyzed. The results indicate that the biomass fluctuates greatly with the service time of the carbon filter and the operation stage. The micro-biological degradation in BAC filters contributes little to the total DOC removal because of the low ratio of BDOC to DOC in the filtered water. The micro-biologically degraded DOC in the 1.5a-carbon filter comprises only 18.8% of total DOC removed, and 26.4% in the 5a-carbon filter. Furthermore, the micro-biological degradation process is not significant for odorous material removal and contributes 32% and 29% to the total removal of 2-MIB and geosmin, respectively, even in the 5a carbon

  8. Generalized Hampel Filters

    Science.gov (United States)

    Pearson, Ronald K.; Neuvo, Yrjö; Astola, Jaakko; Gabbouj, Moncef

    2016-12-01

    The standard median filter based on a symmetric moving window has only one tuning parameter: the window width. Despite this limitation, this filter has proven extremely useful and has motivated a number of extensions: weighted median filters, recursive median filters, and various cascade structures. The Hampel filter is a member of the class of decsion filters that replaces the central value in the data window with the median if it lies far enough from the median to be deemed an outlier. This filter depends on both the window width and an additional tuning parameter t, reducing to the median filter when t=0, so it may be regarded as another median filter extension. This paper adopts this view, defining and exploring the class of generalized Hampel filters obtained by applying the median filter extensions listed above: weighted Hampel filters, recursive Hampel filters, and their cascades. An important concept introduced here is that of an implosion sequence, a signal for which generalized Hampel filter performance is independent of the threshold parameter t. These sequences are important because the added flexibility of the generalized Hampel filters offers no practical advantage for implosion sequences. Partial characterization results are presented for these sequences, as are useful relationships between root sequences for generalized Hampel filters and their median-based counterparts. To illustrate the performance of this filter class, two examples are considered: one is simulation-based, providing a basis for quantitative evaluation of signal recovery performance as a function of t, while the other is a sequence of monthly Italian industrial production index values that exhibits glaring outliers.

  9. Carbonaceous materials in petrochemical wastewater before and after treatment in an aerated submerged fixed-bed biofilm reactor

    Directory of Open Access Journals (Sweden)

    Trojanowicz Karol

    2016-09-01

    Full Text Available Results of the studies for determining fractions of organic contaminants in a pretreated petrochemical wastewater flowing into a pilot Aerated Submerged Fixed-Bed Biofilm Reactor (ASFBBR are presented and discussed. The method of chemical oxygen demand (COD fractionation consisted of physical tests and biological assays. It was found that the main part of the total COD in the petrochemical, pretreated wastewater was soluble organic substance with average value of 57.6%. The fractions of particulate and colloidal organic matter were found to be 31.8% and 10.6%, respectively. About 40% of COD in the influent was determined as readily biodegradable COD. The inert fraction of the soluble organic matter in the petrochemical wastewater constituted about 60% of the influent colloidal and soluble COD. Determination of degree of hydrolysis (DH of the colloidal fraction of COD was also included in the paper. The estimated value of DH was about 62%. Values of the assayed COD fractions were compared with the same parameters obtained for municipal wastewater by other authors.

  10. Oxidation of aqueous EDTA and associated organics and coprecipitation of inorganics by ambient iron-mediated aeration.

    Science.gov (United States)

    Englehardt, James D; Meeroff, Daniel E; Echegoyen, Luis; Deng, Yang; Raymo, Françisco M; Shibata, Tomoyuki

    2007-01-01

    Cationic metal and radionuclide contaminants can be extracted from soils to groundwater with sequestering agents such as EDTA. However, EDTA must then be removed fromthe groundwater, by advanced oxidation or specialized biological treatment. In this work, aqueous individual metal-EDTA solutions were aerated with steel wool for 25 h, at ambient pH, temperature, and pressure. Removal of approximately 99% of EDTA (0.09-1.78 mM); glyoxylic acid (0.153 mM); chelated Cd2+ (0.94 and 0.0952 mM), Pb2+ (0.0502 mM), and Hg2+ (0.0419 mM); and free chromate and vanadate was shown. EDTA was oxidized to glyoxylic acid and formaldehyde, and metals/metalloids were coprecipitated together with iron oxyhydroxide floc. Free arsenite and arsenate were each removed at 99.97%. Free Sr2+, and chelated Ni2+ were removed at 92% and 63%, respectively. Similar removals were obtained from mixtures, including 99.996+/-0.004% removal of total arsenic (95% confidence). Traces of iminodiacetic acid, nitrilotriacetic acid, and ethylenediaminetriacetic acid were detected after 25 h. Results are consistent with first-order, solution-phase oxidation of EDTA and glyoxylic acid by ferryl ion and H202, respectively, with inhibition due to sludge accumulation, and equilibrium metal coprecipitation. This ambient process, to our knowledge previously unknown, agrees with recently reported findings and shows promise for remediation of metals, metalloids, and radionuclides in wastewater, soil, and sediment.

  11. Bias aware Kalman filters

    DEFF Research Database (Denmark)

    Drecourt, J.-P.; Madsen, H.; Rosbjerg, Dan

    2006-01-01

    This paper reviews two different approaches that have been proposed to tackle the problems of model bias with the Kalman filter: the use of a colored noise model and the implementation of a separate bias filter. Both filters are implemented with and without feedback of the bias into the model state...... are illustrated on a simple one-dimensional groundwater problem. The results show that the presented filters outperform the standard Kalman filter and that the implementations with bias feedback work in more general conditions than the implementations without feedback. 2005 Elsevier Ltd. All rights reserved........ The colored noise filter formulation is extended to correct both time correlated and uncorrelated model error components. A more stable version of the separate filter without feedback is presented. The filters are implemented in an ensemble framework using Latin hypercube sampling. The techniques...

  12. MST Filterability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-12

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRR was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO2, and NaNO3) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.

  13. 高铁高锰微污染地下水的生物同层净化研究%Biological Removal of High-concentration Fe and Mn from Micro-polluted Groundwater Using a Single Filter

    Institute of Scientific and Technical Information of China (English)

    张建林; 李相昆; 曾辉平; 佟伟云; 张杰

    2011-01-01

    向经过曝气的高铁高锰深井地下水中加入生活污水以模拟微污染地下水,并考察了生物除铁除锰滤池对其的净化效果.滤柱高为2.7m,内径为60 mm,内装填除铁除锰能力已经成熟的锰砂,设计滤速为6 m/h.研究了去除有机物滤层的培养过程及在不同滤速下对各污染物的去除规律,结果表明:生物滤柱对微污染地下水具有良好的净化效果,其中,Fe的高效去除区间在滤层上部,Mn和有机物可以实现同层去除,高效去除区间在滤层中下部;当进水有机物浓度较高时,沿程的溶解氧浓度会逐渐降低,导致对CODMn和Mn的去除效果变差,此时应考虑在滤层中部或底部增加曝气来提高溶解氧.%Domestic sewage was added into aerated groundwater with high concentration of Fe and Mn to simulate micro-polluted groundwater, and the removal efficiency of pollutants was investigated in a biofilter column with height of 2. 7 m, internal diameter of 60 mm and filtration velocity of 6 m/h and filled with mature manganese sand. Organism cultivation process and the removal rule of pollutants under different filtration rates were studied. The results indicate that the biofilter column has a good purification efficiency of micro-polluted groundwater. Fe is removed in the upper part of the biofilter column effectively , Mn and organics are both removed in the middle and lower parts effectively. DO concentration is reduced when the influent organic concentration is higher. As a result, the removal efficiencies of CODMN and Mn become poor. In this situation, aeration should be added in the middle or lower parts to improve ' DO.

  14. Guided image filtering.

    Science.gov (United States)

    He, Kaiming; Sun, Jian; Tang, Xiaoou

    2013-06-01

    In this paper, we propose a novel explicit image filter called guided filter. Derived from a local linear model, the guided filter computes the filtering output by considering the content of a guidance image, which can be the input image itself or another different image. The guided filter can be used as an edge-preserving smoothing operator like the popular bilateral filter [1], but it has better behaviors near edges. The guided filter is also a more generic concept beyond smoothing: It can transfer the structures of the guidance image to the filtering output, enabling new filtering applications like dehazing and guided feathering. Moreover, the guided filter naturally has a fast and nonapproximate linear time algorithm, regardless of the kernel size and the intensity range. Currently, it is one of the fastest edge-preserving filters. Experiments show that the guided filter is both effective and efficient in a great variety of computer vision and computer graphics applications, including edge-aware smoothing, detail enhancement, HDR compression, image matting/feathering, dehazing, joint upsampling, etc.

  15. Effects of aeration rate on degradation process of oil palm empty fruit bunch with kinetic-dynamic modeling.

    Science.gov (United States)

    Talib, Ahmad Tarmezee; Mokhtar, Mohd Noriznan; Baharuddin, Azhari Samsu; Sulaiman, Alawi

    2014-10-01

    The effect of different aeration rates on the organic matter (OM) degradation during the active phase of oil palm empty fruit bunch (EFB)-rabbit manure co-composting process under constant forced-aeration system has been studied. Four different aeration rates, 0.13 L min(-1) kg(DM)(-1),0.26 L min(-1) kg(DM)(-1),0.49 L min(-1) kg(DM)(-1) and 0.74 L min(-1) kg(DM)(-1) were applied. 0.26 L min(-1) kg(DM)(-1) provided enough oxygen level (10%) for the rest of composting period, showing 40.5% of OM reduction that is better than other aeration rates. A dynamic mathematical model describing OM degradation, based on the ratio between OM content and initial OM content with correction functions of moisture content, free air space, oxygen and temperature has been proposed.

  16. Optimization of Energy Consumption and Mass Transfer Parameters in a Surface Aeration Vessel.

    Science.gov (United States)

    Mohammadpour, A; AkhavanBehabadi, M A; Ebrahimzadeh, M; Raisee, M; MajdiNasab, A R; Nosrati, M; Mousavi, S M

    2016-04-01

    This paper reports tests on a lab-scale surface aeration vessel was equipped with a Rushton turbine to examine its performance in terms of standard aeration efficiency (SAE), mixing time, and void fraction characteristics. These characteristics were investigated by tests using variations of rotor speed, impeller immersion depth, and water level. Results showed that variation of impeller immersion depth had a greater effect on the SAE compared to variation of water level. Moreover, the SAE increased with rotor speeds up to about 150 to 200 rpm and then decreased. In addition, void fraction improved by impeller immersion depth and rotor speed enhancement; however, mixing time and power number were reduced as rotor speed increased. According to the response surface methodology statistical optimizations, optimum values for rotor speed, impeller immersion depth, and water level were 168.90 rpm, 25 mm, and 30 cm, respectively, to achieve the maximum value of SAE.

  17. Nonlinear control of an activated sludge aeration process: use of fuzzy techniques for tuning PID controllers.

    Science.gov (United States)

    Rodrigo, M A; Seco, A; Ferrer, J; Penya-roja, J M; Valverde, J L

    1999-01-01

    In this paper, several tuning algorithms, specifically ITAE, IMC and Cohen and Coon, were applied in order to tune an activated sludge aeration PID controller. Performance results of these controllers were compared by simulation with those obtained by using a nonlinear fuzzy PID controller. In order to design this controller, a trial and error procedure was used to determine, as a function of error at current time and at a previous time, sets of parameters (including controller gain, integral time and derivative time) which achieve satisfactory response of a PID controller actuating over the aeration process. Once these sets of data were obtained, neural networks were used to obtain fuzzy membership functions and fuzzy rules of the fuzzy PID controller.

  18. Effect of micro-aeration and inoculum type on the biodegradation of lignocellulosic substrate

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis; Kougias, Panagiotis; Vasileiou, S. A.;

    2017-01-01

    duration, resulting in the highest methane production. The oxygen load had the largest impact on the biodegradability of straw, among the examined variables. More specifically, a micro-aeration intensity of 10mLO2/gVS was identified as the critical threshold above which the AD performance was more......The effect of various micro-aeration strategies on the anaerobic digestion (AD) of wheat straw was thoroughly examined using a mixture of inocula, containing compost and well digested sludge from biogas plant. The aim was to determine the most efficient oxygen load, pulse repetition and treatment...... susceptible to instability. The highest enhancement in biogas production was achieved by injecting 5mLO2/gVS for a consecutive 3-day treatment period, presenting a 7.2% increase compared to the untreated wheat straw. Nevertheless, the results from optimisation case study indicated a higher increase of 9...

  19. Binary effect of fly ash and palm oil fuel ash on heat of hydration aerated concrete.

    Science.gov (United States)

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa; Sajjadi, Seyed Mahdi

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern.

  20. THE INFLUENCE OF A HALLOYSITE ADDITIVE ON THE PERFORMANCE OF AUTOCLAVED AERATED CONCRETE

    Directory of Open Access Journals (Sweden)

    Z. Owsiak

    2015-03-01

    Full Text Available This paper presents the results from the tests of autoclaved aerated concrete with halloysite as a cement additive. Good pozzolanic properties make it a suitable material to be used as a partial replacement of a portion of cement. Basic physical and mechanical properties of the composites with various mineral content are discussed. The compressive strength test results indicate an increase in strength of the AAC containing 2.5 % and 5 % halloysite relative to the reference specimen. Thermal conductivity and density values remained at the same level. Observations of the microstructure in the scanning electron microscope confirmed the results from the XRD tests. Anhydrite was observed in addition to tobermorite. The results from the tests of the autoclaved aerated concretes in which halloysite was incorporated as 7.5 % and 10 % cement replacement showed an increase in compressive strength, density and thermal conductivity values.

  1. Settlement determination of operating moisture of autoclaved aerated concrete in different climatic zones

    Directory of Open Access Journals (Sweden)

    Pastushkov Pavel Pavlovich

    Full Text Available In the process of operation of buildings the moisture state of enveloping structures materials is changing depending on their construction features, properties of the material, temperature and moisture conditions in the premises, climatic conditions of the construction area. Moisture mode determines the operational properties of the enveloping structures of a building. It directly influences the thermal characteristics of enveloping structure and energy efficiency of the applied materials. The analysis of the methods for calculation of moisture behavior of enclosing structures is carried out. The research relevance of operational moisture of AAC is substantiated. Experimental studies and results of the sorption moisturizing and water vapor permeability of leading marks of aerated concrete are carried out. The authors offer the results of numerical calculations of the moisture behavior of aerated concrete in the walls with mark D400 with facade thermal insulation composite systems - with external plaster layers for different climatic zones of construction.

  2. Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste.

    Science.gov (United States)

    Xu, Suyun; Selvam, Ammaiyappan; Wong, Jonathan W C

    2014-02-01

    Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35°C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21-27% and 38-64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH4/g VS(added) in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO2 respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.

  3. Sludge reduction by direct addition of chlorine dioxide into a sequencing batch reactor under operational mode of repeatedly alternating aeration/non-aeration.

    Science.gov (United States)

    Peng, Hong; Liu, Weiyi; Li, Yuanmei; Xiao, Hong

    2015-01-01

    The effect of direct addition of chlorine dioxide (ClO2) into a repeatedly alternating aeration/non-aeration sequencing batch reactor (SBR) on its sludge reduction and process performance was investigated. The experimental results showed that the sludge reduction efficiency was 32.9% and the observed growth yield (Yobs) of SBR was 0.11 kg VSS (volatile suspended solids) /kg COD (chemical oxygen demand) for 80 days' operation at the optimum ClO2 dosage of 2.0 mg/g TSS (total suspended solids). It was speculated that cell lysis and cryptic growth, uncoupled metabolism and endogenous metabolism were jointly responsible for the sludge reduction in this study. COD, NH3-N, total nitrogen (TN) and total phosphorus (TP) in the effluent increased on average 29.47, 4.44, 1.97 and 0.05 mg/L, respectively. However, the effluent quality still satisfied the first-class B discharge standards for municipal wastewater treatment plants in China. In that case, the sludge maintained fine viability with the specific oxygen uptake rate (SOUR) being 14.47 mg O2/(g VSS·h) and demonstrated good settleability with the sludge volume index (SVI) being 116 mL/g. The extra cost of sludge reduction at the optimum ClO2 dosage was estimated to be 2.24 CNY (or 0.36 dollar)/kg dry sludge.

  4. Solar-energy mobile water aerators are efficient for restoring eutrophic water

    Science.gov (United States)

    Wang, Y. Y.; Xu, Z. X.

    2017-01-01

    Surface water eutrophication has become a worldwide social issue. large amounts of secondhand energy, high capital investment are required, and most ecosystem disturbances will arise in the conventional eutrophication restoration measures. However, mobile solar-energy water aerator has the better oxygen transfer rate, hydrodynamic condition and can be used in the large waterbody for its cruising character. Second, the device is low carbon and sustainable for the solar photovoltaic system applications. So the device can be widely used in the eutrophication restoration.

  5. The Influence of Micropore Oxygen Aeration on the Pond Water Quality Environment

    Directory of Open Access Journals (Sweden)

    Xiao-Jiang Chen

    2013-11-01

    Full Text Available In order to know the effects of micropore oxygen aeration on the water quality and economic output, take each 3 of micropore oxygen aeration (experimental pond and impeller oxygenation (control pond to make the comparison, indexs of two different aeration methods water were detected from May, 2012 to October, 2012. Such as water temperature, dissolved oxygen, ammonia nitrogen and nitrite, phytoplankton, chemical oxygen demand (CODMn. Results showed that, (1 the indexes of the dissolved oxygen, ammonia nitrogen, chemical oxygen demand(CODMn and nitrite of the experimental pond are all superior to that of the control pond, of which the concentration of the dissolved oxygen of the experimental pond is 8.37 mg/L which is higher than that of the control pond (5.7 mg/L. And, (CODMn in the experimental pond is 7.54 mg/L, lower than that in the control pond (10.19 mg/L. The difference between the control pond and the experimental pond was statistically significant (p<0.01. The ammonia nitrogen of the experimental pond is 0.1 mg/L, obviously lower than the control pond (0.16 mg/L. Besides, the nitrite is 0.13 mg/L in the experimental pond, lower than that of the control pond (0.21 mg/L. (2 Compared with the control pond, the experimental pond has quite higher general abundance of algae, with about 5.69×108 ind/L. Yet, there is no obvious difference between them. (3 Compared to the impeller oxygenation, the micropore oxygen aeration technology can be better to increase the dissolved oxygen in the aquaculture pond and improve the water quality. However, there is no significant influence to the phytoplankton abundance and diversity.

  6. Turbine Aeration Design Software for Mitigating Adverse Environmental Impacts Resulting From Conventional Hydropower Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Gulliver, John S. [Univ. of Minnesota, Minneapolis, MN (United States)

    2015-03-01

    Conventional hydropower turbine aeration test-bed for computational routines and software tools for improving environmental mitigation technologies for conventional hydropower systems. In achieving this goal, we have partnered with Alstom, a global leader in energy technology development and United States power generation, with additional funding from the Initiative for Renewable Energy and the Environment (IREE) and the College of Science and Engineering (CSE) at the UMN

  7. Influence of free air space on microbial kinetics in passively aerated compost.

    Science.gov (United States)

    Yu, Shouhai; Clark, O Grant; Leonard, Jerry J

    2009-01-01

    The influence of free air space (FAS) on passively aerated composting has been reported, but the quantitative relationship between FAS and the microbial kinetics in passively aerated compost has not been investigated. This relationship was studied by composting dairy manure and straw in an enclosed, passively aerated, cylindrical vessel. Based on this experimental system, conceptual and numerical models were developed in which the compost bed was considered to consist of layered elements, each being physically and chemically homogeneous. The microbial activity in each layer was represented in order to predict oxygen and substrate consumption and the release of water and heat. Convective transport of air, moisture, and heat through the layers was represented. Microbial growth and substrate consumption rates were described using modified first-order kinetics for each of the mesophilic and thermophilic temperature regimes. The values of the microbial kinetic parameters were adjusted for each layer based on an innovative, non-linear, statistical analysis of temperature histories recorded at different layers in the compost bed during three treatments (i.e., FAS values of 0.45, 0.52, and 0.65). Microbial kinetic rate constants were found to follow a sigmoid relationship with FAS, with correlation coefficients (R(2)) of 0.97 for the mesophilic stage and 0.96 for the thermophilic stage. Temperature histories and airflow measurements from a fourth treatment (FAS value of 0.57) were used as an independent check of the model's performance. Simulation results indicate that the model could predict the general trend of temperature development. A plot of the residuals shows that the model is biased, however, possibly because many parameters in the model were not measured directly but instead were estimated from literature. The result from this study demonstrates a new method for describing the relationship between microbial kinetics (k(max)) and substrate FAS, which could be used

  8. Mesocosm-scale evaluation of faunal and microbial communities of aerated and unaerated leachfield soil.

    Science.gov (United States)

    Amador, José A; Potts, David A; Savin, Mary C; Tomlinson, Peter; Görres, Josef H; Nicosia, Erika L

    2006-01-01

    Aeration improves the capacity of leachfields to decontaminate and reduce the nutrient load of wastewater. To gain a better understanding of the effects of aeration, we examined the faunal and microbial communities of septic system leachfield soil (0-4 and 4-13 cm) using replicated (n = 3) mesocosms that were actively aerated (AIR) or unaerated (LEACH). Protozoa were 40 to 140 times more abundant in AIR than in LEACH soil. No nematodes were found in LEACH soil, whereas AIR soil contained 5 to 14 x 10(3) nematodes (all bacteriovores) kg(-1). Active microbial biomass was four to five times higher in AIR than LEACH soil. Proteobacteria and actinomycetes/sulfate-reducing bacteria constituted a higher proportion of the community in AIR soil, whereas anaerobic Gram-negative bacteria/firmicutes were more prominent in LEACH soil. Ratios of prokaryotic to eukaryotic phospholipid fatty acids (PLFAs) were higher in LEACH soil, as were membrane stress index values, whereas the starvation index was higher in AIR soil. Community-level physiological profiles showed that 29 and 30 different substrates were used for growth by LEACH and AIR soil microorganisms, respectively. The AIR soil had more microorganisms capable of growing on 10 substrates, whereas growth on two substrates was higher in LEACH soil. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of 16S rRNA gene fragments revealed greater diversity of dominant phylotypes in AIR than LEACH soil, with communities separated by treatment. Aerated leachfield soil had a larger and more diverse faunal and microbial community than unaerated soil, possibly due to differences in the type and availability of electron acceptors.

  9. Non-aerated burner reduces drying costs; Diffusiebrander maakt drogen goedkoper

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, F.P. [Gasunie Research, Groningen (Netherlands)

    1998-10-01

    Gas-fired tumble dryers are more expensive than electric dryers. However, consumers appear to be more satisfied about the drying results of gas-fired tumble dryers. Since premix burner lead to higher natural gas conversion costs, Gasunie Research developed a non-aerated burner, featuring a simple design and a limited number of parts. Moreover, it can be manufactured at low cost, which should improve the competitiveness of the gas-fired tumble dryer

  10. A unified Kalman filter

    Science.gov (United States)

    Stubberud, Allen R.

    2017-01-01

    When considering problems of linear sequential estimation, two versions of the Kalman filter, the continuous-time version and the discrete-time version, are often used. (A hybrid filter also exists.) In many applications in which the Kalman filter is used, the system to which the filter is applied is a linear continuous-time system, but the Kalman filter is implemented on a digital computer, a discrete-time device. The two general approaches for developing a discrete-time filter for implementation on a digital computer are: (1) approximate the continuous-time system by a discrete-time system (called discretization of the continuous-time system) and develop a filter for the discrete-time approximation; and (2) develop a continuous-time filter for the system and then discretize the continuous-time filter. Generally, the two discrete-time filters will be different, that is, it can be said that discretization and filter generation are not, in general, commutative operations. As a result, any relationship between the discrete-time and continuous-time versions of the filter for the same continuous-time system is often obfuscated. This is particularly true when an attempt is made to generate the continuous-time version of the Kalman filter through a simple limiting process (the sample period going to zero) applied to the discrete-time version. The correct result is, generally, not obtained. In a 1961 research report, Kalman showed that the continuous-time Kalman filter can be obtained from the discrete-time Kalman filter by taking limits as the sample period goes to zero if the white noise process for the continuous-time version is appropriately defined. Using this basic concept, a discrete-time Kalman filter can be developed for a continuous-time system as follows: (1) discretize the continuous-time system using Kalman's technique; and (2) develop a discrete-time Kalman filter for that discrete-time system. Kalman's results show that the discrete-time filter generated in

  11. Computer Aided Filter Design.

    Science.gov (United States)

    1987-12-01

    FIR filter can be described in the following. [Ref. 2] 1. FIR filters with exact linear phase can be easily designed. Linear phase filters are important...response for the four cases of linear phase filter , i.e., even or odd symmetry with an even or odd number of terms, can be written in the form: H (eJ ) = e...Ansari, The Design and Application of Optimal FIR Fractional Phase Filters , IEEE on Acoutics, Speech and Signal Processing, Vol. 2, 1987, pp.896-899. 77 14

  12. Effect of Treating Wastewater from Intensive Fish Ponds by Biological Filter%生物滤料净化精养池塘废水的效果研究

    Institute of Scientific and Technical Information of China (English)

    王璐; 刘玥姗; 傅啊慧; 陈睿; 敬小军

    2013-01-01

    [Objective]To study the effect of bio-filer to treat wastewater. [ Method] The bio-filter was hung in the aquarium close to windows for treatment of wastewater from in intensive fish pond. Four test groups were designed in the experiment; controlled group (no bio-filter) , No. 1 group (5 bundles of bio-filter) , No. 2 group (10 bundles of bio-filter) and No. 3 group (15 bundles of bio-filter) , the purificating effect of bio-filter on water quality and optimal configuration were studued. [Result] The bio-filter was effective on the removal of total nitrogen and nitrite nitrogen, and on improving DO. Through analysis of water quality parameters, No. 2 group showed the best effect on water purification. [ Conclusion] Bio-filter was effective on wastewater treatment of intensive fish pond. The optimal density of bio-filter in the indoor experiment for water purification was 0.07 bundles /L (water).%[目的]研究生物刷净化废水的效果.[方法]通过在临窗水族箱内吊挂生物刷的方法来净化精养池塘的废水.设置了对照组(无生物刷)、试验组①(5串生物刷)、试验组②(10串生物刷)和试验组③(15串生物刷),研究生物刷对水质的改善作用和最优的配置密度.[结果]生物刷对TN、NO2均有一定的去除效果,对DO的升高也有一定的作用;在此试验条件下,试验组②生物滤料净化精养池水的综合效果最佳.[结论]生物刷对精养池塘废水具有良好的净化效果,在此试验条件下,净化废水所需的最优密度配置为0.07串/L.

  13. Effects of the combination of aeration and biofilm technology on transformation of nitrogen in black-odor river.

    Science.gov (United States)

    Pan, Mei; Zhao, Jun; Zhen, Shucong; Heng, Sheng; Wu, Jie

    2016-01-01

    Excess nitrogen in urban river networks leading to eutrophication has become one of the most urgent environmental problems. Combinations of different aeration and biofilm techniques was designed to remove nitrogen from rivers. In laboratory water tank simulation experiments, we assessed the removal efficiency of nitrogen in both the overlying water and sediments by using the combination of the aeration and biofilm techniques, and then analyzed the transformation of nitrogen during the experiments. Aeration (especially sediment aeration) combined with the biofilms techniques was proved efficient in removing nitrogen from polluted rivers. Results indicated that the combination of sediment aeration and biofilms, with the highest nitrogen removal rate from the overlying water and sediments, was the most effective combined process, which especially inhibited the potential release of nitrogen from sediments by reducing the enzyme activity. It was found that the content of dissolved oxygen in water could be restored on the basis of the application of aeration techniques ahead, and the biofilm technique would be effective in purifying water in black-odor rivers.

  14. The effect of aeration and effluent recycling on domestic wastewater treatment in a pilot-plant system of duckweed ponds.

    Science.gov (United States)

    Ben-shalom, Miriam; Shandalov, Semion; Brenner, Asher; Oron, Gideon

    2014-01-01

    Three pilot-scale duckweed pond (DP) wastewater treatment systems were designed and operated to examine the effect of aeration and effluent recycling on treatment efficiency. Each system consisted of two DPs in series fed by pre-settled domestic sewage. The first system (duckweed+ conventional treatment) was 'natural' and included only duckweed plants. The second system (duckweed aeration) included aeration in the second pond. The third system (duckweed+ aeration+ circulation) included aeration in the second pond and effluent recycling from the second to the first pond. All three systems demonstrated similarly efficient removal of organic matter and nutrients. Supplemental aeration had no effect on either dissolved oxygen levels or on pollutant removal efficiencies. Although recycling had almost no influence on nutrient removal efficiencies, it had a positive impact on chemical oxygen demand and total suspended solids removals due to equalization of load and pH, which suppressed algae growth. Recycling also improved the appearance and growth rate of the duckweed plants, especially during heavy wastewater loads.

  15. Influence of aeration on volatile sulfur compounds (VSCs) and NH3 emissions during aerobic composting of kitchen waste.

    Science.gov (United States)

    Zhang, Hongyu; Li, Guoxue; Gu, Jun; Wang, Guiqin; Li, Yangyang; Zhang, Difang

    2016-12-01

    This study investigates the influence of aeration on volatile sulfur compounds (VSCs) and ammonia (NH3) emissions during kitchen waste composting. Aerobic composting of kitchen waste and cornstalks was conducted at a ratio of 85:15 (wet weight basis) in 60L reactors for 30days. The gas emissions were analyzed with force aeration at rates of 0.1 (A1), 0.2 (A2) and 0.3 (A3) L (kgDMmin)(-1), respectively. Results showed that VSCs emission at the low aeration rate (A1) was more significant than that at other two rates (i.e., A2 and A3 treatment), where no considerable emission difference was observed. On the other hand, NH3 emission reduced as the aeration rate decreased. It is noteworthy that the aeration rate did not significantly affect the compost quality. These results suggest that the aeration rate of 0.2L (kgDMmin)(-1) may be applied to control VSCs and NH3 emissions during kitchen waste composting.

  16. Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsui, Hirofumi, E-mail: jm-tsutsuih@kochi-u.ac.jp [Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Fujiwara, Taku [Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Inoue, Daisuke [Department of Health Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara-Minami, Kanagawa (Japan); Japan Science and Technology Agency, CREST (Japan); Ito, Ryusei [Department of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido (Japan); Japan Science and Technology Agency, CREST (Japan); Matsukawa, Kazutsugu [Research and Education Faculty, Multidisciplinary Science Cluster, Life and Environmental Medicine Science Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Funamizu, Naoyuki [Department of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido (Japan); Japan Science and Technology Agency, CREST (Japan)

    2015-08-15

    Highlights: • RQ can be an indicator of N{sub 2}O emission in forced aerated composting process. • Emission of N{sub 2}O with nitrification was observed with RQ decrease. • Mass balances demonstrated the RQ decrease was caused by nitrification. • Conversion ratio of oxidized ammonia and total N to N{sub 2}O were ∼2.7%. - Abstract: We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N{sub 2}O) emission in forced aerated composting using lab-scale reactors. Relatively high RQ values from degradation of readily degradable organics initially occurred. RQ then stabilized at slightly lower values, then decreased. Continuous emission of N{sub 2}O was observed during the RQ decrease. Correlation between nitrification and N{sub 2}O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O{sub 2} consumption of nitrification (∼24.8 mmol) was slightly higher than that of CO{sub 2} emission (∼20.0 mmol), indicating that the RQ decrease was caused by the occurrence of nitrification. Results indicate that RQ is a useful index, which not only reflects the bioavailability of organics but also predicts the occurrence of nitrification and N{sub 2}O emission in forced aerated composting.

  17. Effectiveness of surface aeration and oxygen injection system in the Athabasca River

    Energy Technology Data Exchange (ETDEWEB)

    Lima-Neto, I.E.; Zhu, D.Z.; Rajaratnam, N.; Yu, T. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Spafford, M. [Alberta-Pacific Forest Industries Ltd. Boyle, AB (Canada); McEachern, P. [Alberta Environment, AB (Canada)

    2005-07-01

    The effectiveness of a pilot oxygen injection program and surface aeration at the open-water lead downstream of the Al-Pac's effluent diffuser was evaluated in this abstract. Dissolved oxygen (DO) is regarded as a proxy for the overall health of a river from the perspectives of organic and nutrient loading. When organic loading is high and DO concentrations become a concern, a mitigation option may be necessary. In this experiment, a modified Streeter-Phelps model described the spatial variation of DO downstream of the diffuser. Reaeration from the open water lead, formed as a result of effluent temperature, was significant. This suggested the importance of accurate prediction of the water lead's size in managing effluent effects. The amount of DO added to the river due to artificial aeration at rates of 3500 and 5000 lbs per day was approximately 55 and 27 per cent of that due to surface reaeration of a 4 and 5 km long open water lead, respectively. The artificial aeration technique evaluated appeared to have higher absorption efficiencies than those for conventional air injection systems. It was concluded that the results of this study will be valuable for future development of accurate DO models for ice-covered rivers as well as in developing and evaluating oxygen injection systems. tabs, figs.

  18. Thermophilic aeration of cattle slurry with whey and/or jam wastes.

    Science.gov (United States)

    Heinonen-Tanski, Helvi; Kiuru, Tapio; Ruuskanen, Juhani; Korhonen, Kari; Koivunen, Jari; Ruokojärvi, Arja

    2005-01-01

    Thermophilic aeration of cattle slurry and food industrial by-products was studied with the aim to improve hygienic qualities of the slurry so that it could be used as a safe fertiliser for berries to be eaten raw. We also wanted to study if the process would be energetically favourable in an arctic climate. Cattle slurry alone or with whey and/or jam waste was treated. The tests were done in a well heat-insulated reactor with a 10 m(3) volume. Temperature increases up to over 70 degrees C could be recorded in 19 days even though some processes were carried out in winter time when the ambient air temperature was less than 0 degrees C. The heat energy formed was higher than the electrical energy needed to carry out the aeration. The hygienic qualities of the aerated product were good with only minor nitrogen losses. The end product could be useful as a fertiliser and soil improving compound to increase the organic matter content of agricultural soil. Cattle slurry alone was well suited as the raw material if attaining a high temperature was the main goal. A part of slurry could be replaced with food-industrial side products. Whey waste suited better for co-composting than jam waste but the mixture of whey, jam waste, and slurry was optimal for composting.

  19. Modeling of mixing in stirred bioreactors 4. mixing time for aerated bacteria, yeasts and fungus broths

    Directory of Open Access Journals (Sweden)

    Cascaval Dan

    2004-01-01

    Full Text Available The mixing time for bioreactors depends mainly on the rheoiogicai properties of the broths, the biomass concentration and morphology, mixing system characteristics and fermentation conditions. For quantifying the influence of these factors on the mixing efficiency for stirred bioreactors, aerated broths of bacteria (P. shermanii, yeasts (S. cerevisiae and fungi (P. chrysogenum, free mycelia and mycelial aggregates of different concentrations have been investigated using a laboratory bioreactor with a double turbine impeller. The experimental data indicated that the influence of the rotation speed, aeration rate and stirrer positions on the mixing intensity strongly differ from one system to another and must be correlated with the microorganism characteristics, namely: the biomass concentration and morphology. Moreover, compared with non-aerated broths, variations of the mixing time with the considered parameters are very different, due to the complex flow mechanism of gas-liquid dispersions. By means of the experimental data and using a multiregression analysis method some mathematical correlations for the mixing time of the general form: tm = a1*Cx2+a2*Cx+a3*IgVa+a4-N2+a5-N+a6/a7*L2+a8*L+a9 were established. The proposed equations offer good agreement with the experiments, the average deviation being ±6.7% - ±9.4 and are adequate for the flow regime Re < 25,000.

  20. Multiple electron transfer systems in oxygen reducing biocathodes revealed by different conditions of aeration/agitation.

    Science.gov (United States)

    Rimboud, Mickaël; Bergel, Alain; Erable, Benjamin

    2016-08-01

    Oxygen reducing biocathodes were formed at -0.2V/SCE (+0.04V/SHE) from compost leachate. Depending on whether aeration was implemented or not, two different redox systems responsible for the electrocatalysis of oxygen reduction were evidenced. System I was observed at low potential (-0.03V/SHE) on cyclic voltammetries (CVs). It appeared during the early formation of the biocathode (few hours) and resisted the hydrodynamic conditions induced by the aeration. System II was observed at higher potential on CV (+0.46V/SHE); it required a longer lag time (up to 10days) and quiescent conditions to produce an electrochemical signal. The hydrodynamic effects produced by the forced aeration led to its extinction. From their different behaviors and examples in the literature, system I was identified as being a membrane-bound cytochrome-related molecule, while system II was identified as a soluble redox mediator excreted by the biofilm. This study highlighted the importance of controlling the local hydrodynamics to design efficient oxygen reducing biocathodes able to operate at high potential.

  1. Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Mutlu, A. Gizem; Jensen, Marlene Mark;

    2014-01-01

    -stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75g-N/L.d) and high nitrogen removal efficiencies (83 +/- 5 and 88 +/- 2%) obtained. Dynamics of liquid phase nitrous (N2O......) and nitric oxide (NO) concentrations were monitored and N2O emissions calculated. Significant decreases in N2O emissions were obtained when the frequency of aeration was increased while maintaining a constant air flow rate (from >6 to 1.7% Delta N2O/Delta TN). However, no significant effect on the emissions...... was noted when the duration of aeration was increased while decreasing air flow rate (10.9 +/- 3.2% Delta N2O/Delta TN). The extant ammonium oxidation activity (mgNH(4)(+)-N/gVSS.min) positively correlated with the specific N2O production rate (mgN(2)O-N/gVSS.min) of the systems. Operating under conditions...

  2. Properties of Agro-Industrial Aerated Concrete as Potential Thermal Insulation for Building

    Directory of Open Access Journals (Sweden)

    Aminudin Eeydzah

    2016-01-01

    Full Text Available The present paper is aiming to provide an actual state of the development of non autoclaved Agro-Industrial aerated concrete by using multiple ashes as improvement of thermal behavior for building. The feasibility of Agro-Industrial wastes as lightweight concrete by utilizing the Palm Oil Fuel Ash (POFA as binder replacement and bottom ash as fine aggregate was investigated in this paper. Portland cement, bottom ash, aluminum powder and lime (Ca(OH2 were used in this study. The POFA was used to replace Portland cement and Hydrated Lime at 0%, 5%, 10% and 15% by weight and aluminum powder was added at 0.75% dry weight in order to form bubbles. The compressive strength, water absorption, porosity and the thermal conductivity test were carried out after the concrete were water cured for 7 days and later being exposed to the air and water until 28days. The results show that the 20% replacements give the optimum strength of 7.143MPa and 30% give the best thermal conductivity with 0.48W/mK. Hence, this study aim, was to develop an agro-industrial aerated concrete good in insulation but having an optimum strength. Hence, it has been found that the more the percentage of POFA is added the lower the thermal conductivity since the pore structure is increasing and by the optimization done, 30% replacement has been chosen as the best mix design for Agro-Industrial Aerated Concrete.

  3. Effects of Aeration Treatment on γ-Aminobutyric Acid Accumulation in Germinated Tartary Buckwheat (Fagopyrum tataricum

    Directory of Open Access Journals (Sweden)

    Yuanxin Guo

    2016-01-01

    Full Text Available To explore the optimum condition of γ-aminobutyric acid (GABA accumulation in germinated tartary buckwheat, effects of some factors including aeration treatment, physiological indexes, air flow rate, culture temperature, and pH value of cultivating solution under hypoxia on GABA in germinated tartary buckwheat were investigated. The results showed that the dark cultures with distilled water at 30°C, 2 days, and aeration stress with 1.0 L/min air flow rate at 30°C were optimal for GABA accumulation. Under these conditions, the predicted content of GABA was up to 371.98 μg/g DW. The analysis of correlation indicated that there was a significant correlation (P<0.01 between GABA accumulation and physiological indexes. Box-Behnken experimental analysis revealed that optimal conditions with aeration treatment for GABA accumulation in germinated tartary buckwheat were air flow rate of 1.04 L/min, culture temperature of 31.25°C, and a pH value of 4.21. Under these conditions, the GABA content was predicted as high as 386.20 μg/g DW, which was close to the measured value (379.00±9.30 μg/g DW. The variance analysis and validation test suggested that this established regression model could predict GABA accumulation in tartary buckwheat during germination.

  4. Ceramic fiber filter technology

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, B.L.; Janney, M.A.

    1996-06-01

    Fibrous filters have been used for centuries to protect individuals from dust, disease, smoke, and other gases or particulates. In the 1970s and 1980s ceramic filters were developed for filtration of hot exhaust gases from diesel engines. Tubular, or candle, filters have been made to remove particles from gases in pressurized fluidized-bed combustion and gasification-combined-cycle power plants. Very efficient filtration is necessary in power plants to protect the turbine blades. The limited lifespan of ceramic candle filters has been a major obstacle in their development. The present work is focused on forming fibrous ceramic filters using a papermaking technique. These filters are highly porous and therefore very lightweight. The papermaking process consists of filtering a slurry of ceramic fibers through a steel screen to form paper. Papermaking and the selection of materials will be discussed, as well as preliminary results describing the geometry of papers and relative strengths.

  5. UV filters for lighting of plants

    Science.gov (United States)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H. K.; Payer, H. D.

    1994-03-01

    The wavelength dependent interaction of biological systems with radiation is commonly described by appropriate action spectra. Particularly effective plant responses are obtained for ultraviolet (UV) radiation. Excess shortwave UV-B radiation will induce genetic defects and plant damage. Besides the ecological discussion of the deleterious effects of the excess UV radiation there is increasing interest in horticultural applications of this spectral region. Several metabolic pathways leading to valuable secondary plant products like colors, odors, taste, or resulting in mechanical strength and vitality are triggered by UV radiation. Thus, in ecologically as well as in economically oriented experiments the exact generation and knowledge of the spectral irradiance, particularly near the UV absorption edge, is essential. The ideal filter 'material' to control the UV absorption edge would be ozone itself. However, due to problems in controlling the toxic and chemically aggressive, instable gas, only rather 'small ozone filters' have been realized so far. In artificial plant lighting conventional solid filter materials such as glass sheets and plastic foils (celluloseacetate or cellulosetriacetate) which can be easily handled have been used to absorb the UV-C and the excess shortwave UV-B radiation of the lamp emissions. Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The aging of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In

  6. Root aeration improves growth and nitrogen accumulation in rice seedlings under low nitrogen.

    Science.gov (United States)

    Zhu, Jingwen; Liang, Jing; Xu, Zhihui; Fan, Xiaorong; Zhou, Quansuo; Shen, Qirong; Xu, Guohua

    2015-11-16

    In wetland soils, changes in oxygen (O2) level in the rhizosphere are believed to influence the behaviour of nutrients and their usage by plants. However, the effect of aeration on nitrogen (N) acquisition under different N supply conditions remains largely unknown. In this study, the rice cultivars Yangdao 6 (YD6, with higher root aerenchyma abundance) and Nongken 57 (NK57, with lower root aerenchyma abundance) were used to evaluate the effects of aeration on rice growth and N accumulation. Our results showed that the number of adventitious roots and the root surface area increased significantly, and ethylene production and aerenchyma formation decreased in both cultivars after external aeration (EA). Five N treatments, including no N (-N), 0.125 mM NH4NO3 (LN), 1.25 mM Ca(NO3)2 (NO3-N), 1.25 mM (NH4)2SO4 (NH4-N) and 1.25 mM NH4NO3 (N/N), were applied to YD6 and NK57 for 2 days under internal aeration or EA conditions. External aeration increased the root biomass in both cultivars and the shoot biomass in NK57 by 18-50 %. The total N concentrations in roots of YD6 grown under -N and LN and of NK57 grown under NO3-N were increased by EA. Expression of OsPAD4, one of four putative genes regulating aerenchyma formation, showed a similar pattern alongside changes in the ethylene level in the EA-treated rice irrespective of the N treatments. Furthermore, expression of the high-affinity nitrate transporter gene OsNRT2.1 was increased by EA under -N, LN and NO3-N conditions. Our data provide evidence of an interaction between O2 and the supply of N in ethylene production, aerenchyma formation and N nutrition through modification of the expression of OsPAD4 and OsNRT2.1.

  7. 通气对复合生物滤池处理晚年期渗滤液污染物效果影响及微生物群落结构分析%Effect of aeration on the treatment of aged landfill leachate by a composite biofilter and its microbial community structure

    Institute of Scientific and Technical Information of China (English)

    戴淑萍; 谢冰; 李斐斐; 吕宝一; 唐媛

    2011-01-01

    以上海老港垃圾填埋场填埋多年的陈垃圾和废弃多孔滤料为填料构建复合生物滤池处理晚年期垃圾渗滤液.研究了不同运行条件下复合生物滤池对晚年期渗滤液的处理效果,并对不同通气状况下功能微生物的数量、组成和群落结构,以及与处理效果之间的关系进行了分析结果表明:通气对污染物的去除率有较明显的提高,在复合生物滤池中部通气条件下(气固比0.3)较未通气复合生物滤池对COD、NH4+-N和TN的去除率分别高出10、30和10个百分点,而继续增大通气(气固比0.4)对污染物质的去除增加不明显.微生物计数结果表明,复合生物滤池上部微生物数量明显多于下部,上部的异样细菌和硝化细菌数量明显增多,亚硝化细菌数量明显减少,反硝化细菌变化不显著.PCR-DGGE结果表明通气较未通气条带数量和亮度有明显的改变,说明通气改变了反应器中的微生物群落结构.测序结果表明滤池中主要的优势微生物与Pseudomonas sp.HPC1354、Alcanivorax sp.521-1、unculturedβ-proteobacterium 、Dechlororomonas aromatica RCB、Proteobacteria.等具有很高的相似性.%Two different media, aged refuse and waste porous filter material, were used to construct composite biofilters. Their treatment efficiencies on mature landfill leachate pollutants under different operating conditions were investigated. The microbial number, composition and structure of functional micro-organism under different aeration conditions, and their relationship with the treatment effects were analyzed. The results showed that the aeration could enhance the pollutant removal significantly. COD, NH/ -N and the TN removal rates with aeration were respectively 10% , 30% and 10% higher than without aeration. Additional aeration had no further influence on pollutant removal. Micro-organism counting showed that the number of bacteria at the top of both aerated and non-aerated

  8. Characterization of a Regenerable Impactor Filter for Spacecraft Cabin Applications

    Science.gov (United States)

    Agui, Juan H.; Vijayakumar, R.

    2015-01-01

    Regenerable filters will play an important role in human exploration beyond low-Earth orbit. Life Support Systems aboard crewed spacecrafts will have to operate reliably and with little maintenance over periods of more than a year, even multiple years. Air filters are a key component of spacecraft life support systems, but they often require frequent routine maintenance. Bacterial filters aboard the International Space Station require almost weekly cleaning of the pre-filter screen to remove large lint debris captured in the microgravity environment. The source of the airborne matter which is collected on the filter screen is typically from clothing fibers, biological matter (hair, skin, nails, etc.) and material wear. Clearly a need for low maintenance filters requiring little to no crew intervention will be vital to the success of the mission. An impactor filter is being developed and tested to address this need. This filter captures large particle matter through inertial separation and impaction methods on collection surfaces, which can be automatically cleaned after they become heavily loaded. The impactor filter can serve as a pre-filter to augment the life of higher efficiency filters that capture fine and ultrafine particles. A prototype of the filter is being tested at the Particulate Filtration Laboratory at NASA Glenn Research Center to determine performance characteristics, including particle cut size and overall efficiency. Model results are presented for the flow characteristics near the orifice plate through which the particle-laden flow is accelerated as well as around the collection bands.

  9. Aerator Selection in Pulping & Papermaking Wastewater Treatment Engineering%造纸废水处理工程曝气器优选

    Institute of Scientific and Technical Information of China (English)

    王少艮; 张会敏

    2013-01-01

    The characteristics and application scopes of existing aeration equipment used in pulping and papermaking wastewater treatment, such as blasting aerator, jet aerator and mechanical aerator were summarized in this paper. To avoid the disadvantage of the existing aeration system, an innovational rotational flow aerator was introduced, and its advantage and engineering examples were discussed.%讨论了现有曝气设备,包括鼓风曝气、射流曝气和机械曝气设备的特点及适用范围,针对现有曝气器在造纸废水应用中的不足,系统介绍了新型高效旋流曝气器的特征及其在造纸废水处理中的应用优势和工程实例.

  10. Generic Kalman Filter Software

    Science.gov (United States)

    Lisano, Michael E., II; Crues, Edwin Z.

    2005-01-01

    The Generic Kalman Filter (GKF) software provides a standard basis for the development of application-specific Kalman-filter programs. Historically, Kalman filters have been implemented by customized programs that must be written, coded, and debugged anew for each unique application, then tested and tuned with simulated or actual measurement data. Total development times for typical Kalman-filter application programs have ranged from months to weeks. The GKF software can simplify the development process and reduce the development time by eliminating the need to re-create the fundamental implementation of the Kalman filter for each new application. The GKF software is written in the ANSI C programming language. It contains a generic Kalman-filter-development directory that, in turn, contains a code for a generic Kalman filter function; more specifically, it contains a generically designed and generically coded implementation of linear, linearized, and extended Kalman filtering algorithms, including algorithms for state- and covariance-update and -propagation functions. The mathematical theory that underlies the algorithms is well known and has been reported extensively in the open technical literature. Also contained in the directory are a header file that defines generic Kalman-filter data structures and prototype functions and template versions of application-specific subfunction and calling navigation/estimation routine code and headers. Once the user has provided a calling routine and the required application-specific subfunctions, the application-specific Kalman-filter software can be compiled and executed immediately. During execution, the generic Kalman-filter function is called from a higher-level navigation or estimation routine that preprocesses measurement data and post-processes output data. The generic Kalman-filter function uses the aforementioned data structures and five implementation- specific subfunctions, which have been developed by the user on

  11. Crux vena cava filter.

    Science.gov (United States)

    Murphy, Erin H; Johnson, Eric D; Kopchok, George E; Fogarty, Thomas J; Arko, Frank R

    2009-09-01

    Inferior vena cava filters are widely accepted for pulmonary embolic prophylaxis in high-risk patients with contraindications to anticoagulation. While long-term complications have been associated with permanent filters, retrievable filters are now available and have resulted in the rapid expansion of this technology. Nonetheless, complications are still reported with optional filters. Furthermore, device tilting and thrombus load may prevent retrieval in up to 30% of patients, thereby eliminating the benefits of this technology. The Crux vena cava filter is a novel, self-centering, low-profile filter that is designed for ease of delivery, retrievability and improved efficacy while limiting fatigue-related device complications. This device has been proven safe and user-friendly in an ovine model and has recently been implanted in human subjects.

  12. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  13. Conservative Noise Filters

    Directory of Open Access Journals (Sweden)

    Mona M.Jamjoom

    2016-05-01

    Full Text Available Noisy training data have a huge negative impact on machine learning algorithms. Noise-filtering algorithms have been proposed to eliminate such noisy instances. In this work, we empirically show that the most popular noise-filtering algorithms have a large False Positive (FP error rate. In other words, these noise filters mistakenly identify genuine instances as outliers and eliminate them. Therefore, we propose more conservative outlier identification criteria that improve the FP error rate and, thus, the performance of the noise filters. With the new filter, an instance is eliminated if and only if it is misclassified by a mutual decision of Naïve Bayesian (NB classifier and the original filtering criteria being used. The number of genuine instances that are incorrectly eliminated is reduced as a result, thereby improving the classification accuracy.

  14. Changes in the chemical and physicochemical properties of the solid fraction of cattle slurry during composting using different aeration strategies.

    Science.gov (United States)

    Cáceres, Rafaela; Flotats, Xavier; Marfà, Oriol

    2006-01-01

    Replacement of peat as a growing medium by a renewable material, such as an organic waste, is an issue of concern since harvesting of peat has a considerable environmental impact and, actually, it is a non-renewable resource. Cattle manure is a readily available organic waste, which means that once it goes through the composting process, it can be used as an alternative to peat, specifically, the solid fraction obtained from mechanical liquid-solid separation of cattle slurry (SF). Studies have shown it to be suitable for such uses. The purpose of this study was to detect possible changes in the physicochemical and chemical properties of SF when it is composted using different aeration strategies, with an emphasis on the changes that would make it feasible for use as a substrate. With this aim in mind, an experiment was designed with three aeration strategies that would be used during composting. The first consisted of applying air through a static method (forced ventilation). The second involved improving aeration by adding a bulking agent and a dynamic turning method. In the third strategy, aeration was carried out by turning (control). The results show that the different aeration strategies had a clear effect on the evolution of pH, electrical conductivity (EC), nitrate-N, ammonia-N and bicarbonate content. Nitrification was favored under good aeration conditions using the static composting method, probably due to the greater availability of ammonia-N that was transformed into nitrate-N. In general, the low buffering capacity allowed for a reduction of the pH during the curing stage of composting (in conjunction with low temperatures during this period), a characteristic that favors the use of this compost as a growing medium. We also conclude that measuring bicarbonate levels during composting could be used as an indicator of the possible acidification of the material and as a way of evaluating the level of material aeration.

  15. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  16. Removal of radon by aeration testing of various aeration techniques for small water works. For European Commission under Contract No FI4PCT960054 TENAWA project

    CERN Document Server

    Salonen, L; Mehtonen, J; Mjoenes, L; Raff, O; Turunen, H

    2002-01-01

    Capability of various aeration techniques to remove radon from water in small waterworks was studied as a part of project (Treatment Techniques for Removing Natural Radionuclides from Drinking Water), which was carried out during 1997-1999 on a cost-shared basis (contract No. F14PCT960054) with The European Commission (CEC) under the supervision of the Directorate-General XII Radiation Protection Research Unit. In TENAWA project both laboratory and field experiments were performed in order to find reliable methods and equipment for removing natural radionuclides from ground water originating either from private wells or small waterworks. Because such techniques are more often needed in private households than at waterworks, the main emphasis of the research was aimed to solve the water treatment problems related to the private water supplies, especially bedrock wells. Radon was the most important radionuclide to be removed from water at waterworks whereas the removal of other radionuclides ( sup 2 sup 3 sup 4...

  17. Comparison of aerosol and bioaerosol collection on air filters

    OpenAIRE

    Miaskiewicz-Peska, Ewa; Lebkowska, Maria

    2011-01-01

    Air filters efficiency is usually determined by non-biological test aerosols, such as potassium chloride particles, Arizona dust or di-ethyl-hexyl-sebacate (DEHS) oily liquid. This research was undertaken to asses, if application of non-biological aerosols reflects air filters capacity to collect particles of biological origin. The collection efficiency for non-biological aerosol was tested with the PALAS set and ISO Fine Test Dust. Flow rate during the filtration process was 720 l/h, and par...

  18. Oriented Fiber Filter Media

    Directory of Open Access Journals (Sweden)

    R. Bharadwaj

    2008-06-01

    Full Text Available Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a thick layered media can improve performance by about 40%. The results also show the improved performance is not monotonically correlated to the average fiber angle of the medium.

  19. Depth filters containing diatomite achieve more efficient particle retention than filters solely containing cellulose fibers

    Directory of Open Access Journals (Sweden)

    Johannes Felix Buyel

    2015-12-01

    Full Text Available The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g. when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m-2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU when diatomite filters were used. We also tested pre coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m-2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

  20. Remediation of Urban River Water by Pontederia Cordata Combined with Artificial Aeration: Organic Matter and Nutrients Removal and Root-Adhered Bacterial Communities.

    Science.gov (United States)

    Gu, Dungang; Xu, Huan; He, Yan; Zhao, Feng; Huang, Minsheng

    2015-01-01

    Macrophyte combined with artificial aeration is a promising in situ remediation approach for urban rivers polluted with nutrients and organic matter. However, seasonal variations and aeration effects on phytoremediation performance and root-adhered microbial communities are still unclear. In this study, Pontederia cordata was used to treat polluted urban river water under various aeration intensities. Results showed that the highest removal efficiencies of chemical oxygen demand (COD(Cr)) and total nitrogen (TN) were attained under aeration of 30 L min(-1) in spring and summer and 15 L min(-1) in autumn, while total phosphorus (TP) removal reached maximum with aeration of 15 L min(-1) in all seasons. Moderate aeration was beneficial for increasing the diversity of root-adhered bacteria communities, and the shift of bacterial community structure was more pronounced in spring and autumn with varying aeration intensity. The dual effect, i.e. turbulence and dissolved oxygen (DO), of aeration on the removal of COD(Cr) and TN prevailed over the individual effect of DO, while DO was the most influential factor for TP removal and the root-adhered bacterial community diversity. P. cordata combined with 15 L min(-1) aeration was deemed to be the best condition tested in this study.