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Sample records for aerated filter baf

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  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. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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)).

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Influence of filtration velocity on DON variation in BAF for micropolluted surface water treatment.

    Science.gov (United States)

    Ma, Teng-Fei; Chen, You-Peng; Kang, Jia; Gao, Xu; Guo, Jin-Song; Fang, Fang; Zhang, Xiao-Tian

    2016-12-01

    Biological aerated filters (BAFs) are widely used for the treatment of micropolluted surface water. However, the biological process produces dissolved organic nitrogen (DON), which, as precursors of nitrogenous disinfection by-products, pose potential threats to drinking water safety. Therefore, to control DON in BAF effluent, it is necessary to study the influence of BAF operation parameters on DON production. In this study, the influence of filtration velocity in a BAF on DON production was investigated. Under different filtration velocity (0.5, 2, and 4 m/h) conditions, profiles of DON concentrations along the media layer were measured. The profile at a filtration velocity of 0.5 m/h showed a decreasing trend, and the ones under filtration velocities of 2 and 4 m/h fluctuated in a small range (from 0.1 to 0.4 mg/L). Moreover, the relatively high filtration velocities of 2 and 4 m/h resulted in a lower level of DON concentration. Additionally, 3D excitation-emission matrix fluorescence spectroscopy was used to characterize DON. It is found that the patterns of DON at a relatively high filtration velocity condition (4 m/h) were obviously different from the ones under low filtration velocity conditions (0.5 and 2 m/h).

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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。

  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. 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

  5. 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

  6. 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.

  7. 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。

  8. 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).

  9. Removal of nitrogen and phosphorus in a combined A2/O-BAF system with a short aerobic SRT

    Institute of Scientific and Technical Information of China (English)

    DING Yong-wei; WANG Lin; WANG Bao-zhen; WANG Zheng

    2006-01-01

    A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter (A2/O-BAF) combined system was carried out to treat wastewater with lower C/N and C/P ratios. The A2/O process was operated in a short aerobic sludge retention time (SRT) for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitrifying phosphate-accumulating organisms (DPAOs). The ratio of DPAOs to phosphorus accumulating organisms (PAOs) could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent retum rates should be controlled with 1-4 mg/L nitrate nitrogen in the anoxic zone effluent of A2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.

  10. 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.

  11. 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.

  12. 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)

  13. 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.

  14. 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

  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. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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).

  1. 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.

  2. 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.

  3. 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。

  4. 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.

  5. The developmental and pathogenic roles of BAF57, a special subunit of the BAF chromatin-remodeling complex.

    Science.gov (United States)

    Lomelí, Hilda; Castillo-Robles, Jorge

    2016-06-01

    Mammalian SWI/SNF or BAF chromatin-remodeling complexes are polymorphic assemblies of homologous subunit families that remodel nucleosomes. BAF57 is a subunit of the BAF complexes; it is encoded only in higher eukaryotes and is present in all mammalian assemblies. Its main structural feature is a high-mobility group domain, the DNA-binding properties of which suggest that BAF57 may play topological roles as the BAF complex enters or exits the nucleosome. BAF57 displays specific interactions with a number of proteins outside the BAF complex. Through these interactions, it can accomplish specific functions. In the embryo, BAF57 is responsible for the silencing of the CD4 gene during T-cell differentiation, and during the repression of neuronal genes in non-neuronal cells, BAF57 interacts with the transcriptional corepressor, Co-REST, and facilitates repression. Extensive work has demonstrated a specific role of BAF57 in regulating the interactions between BAF and nuclear hormone receptors. Despite its involvement in oncogenic pathways, new generation sequencing studies do not support a prominent role for BAF57 in the initiation of cancer. On the other hand, evidence has emerged to support a role for BAF57 as a metastasis factor, a prognosis marker and a therapeutic target. In humans, BAF57 is associated with disease, as mutations in this gene predispose to important congenital disorders, including menigioma disease or the Coffin-Siris syndrome. In this article, we present an exhaustive analysis of the BAF57 molecular and biochemical properties, cellular functions, loss-of-function phenotypes in living organisms and pathological manifestations in cases of human mutations.

  6. 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.

  7. 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.

  8. 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...

  9. 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。

  10. 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.

  11. BAF180 regulates cellular senescence and hematopoietic stem cell homeostasis through p21.

    Science.gov (United States)

    Lee, Hyemin; Dai, Fangyan; Zhuang, Li; Xiao, Zhen-Dong; Kim, Jongchan; Zhang, Yilei; Ma, Li; You, M James; Wang, Zhong; Gan, Boyi

    2016-04-12

    BAF180 (also called PBRM1), a subunit of the SWI/SNF complex, plays critical roles in the regulation of chromatin remodeling and gene transcription, and is frequently mutated in several human cancers. However, the role of mammalian BAF180 in tumor suppression and tissue maintenance in vivo remains largely unknown. Here, using a conditional somatic knockout approach, we explored the cellular and organismal functions of BAF180 in mouse. BAF180 deletion in primary mouse embryonic fibroblasts (MEFs) triggers profound cell cycle arrest, premature cellular senescence, without affecting DNA damage response or chromosomal integrity. While somatic deletion of BAF180 in adult mice does not provoke tumor development, BAF180 deficient mice exhibit defects in hematopoietic system characterized by progressive reduction of hematopoietic stem cells (HSCs), defective long-term repopulating potential, and hematopoietic lineage developmental aberrations. BAF180 deletion results in elevated p21 expression in both MEFs and HSCs. Mechanistically, we showed that BAF180 binds to p21 promoter, and BAF180 deletion enhances the binding of modified histones associated with transcriptional activation on p21 promoter. Deletion of p21 rescues cell cycle arrest and premature senescence in BAF180 deficient MEFs, and partially rescues hematopoietic defects in BAF180 deficient mice. Together, our study identifies BAF180 as a critical regulator of cellular senescence and HSC homeostasis, which is at least partially regulated through BAF180-mediated suppression of p21 expression. Our results also suggest that senescence triggered by BAF180 inactivation may serve as a failsafe mechanism to restrain BAF180 deficiency-associated tumor development, providing a conceptual framework to further understand BAF180 function in tumor biology.

  12. 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.

  13. Knockdown Brm and Baf170, components of chromatin remodeling complex, facilitates reprogramming of somatic cells

    Science.gov (United States)

    The SWI/SNF (SWItch/Sucrose NonFermentable or BAF, Brg/Brahma-associated factors) complexes are epigenetic modifiers of chromatin structure and undergo progressive changes in subunit composition during cellular differentiation. For example, in embryonic stem cells (ESCs) esBAF contains Brg1 and Baf...

  14. 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.

  15. Study on determination of biofilm activity in BAF by TTC-dehydrogenase assay%优化TTC-脱氢酶还原法测定陶粒负载微生物活性

    Institute of Scientific and Technical Information of China (English)

    齐鲁青; 汪晓军; 詹德明

    2012-01-01

    利用氯化三苯基四氮唑(TTC)-脱氢酶还原法定量测定了曝气生物滤池中陶粒负载生物膜的活性,并对影响生物活性测定的因素进行了分析和优化.实验表明,经优化后得出最佳培养条件是:陶粒采用原位法制样,依次加入pH为8.0的Tris-HCl缓冲液,质量分数为0.4%的TTC溶液,0.1 mol/L葡萄糖溶液,在温度40℃下培养4h,最后生成的三苯基甲臢(TriphenylFormazone,TF)用甲苯萃取可以除去有色废水的颜色影响.采用TTC-脱氢酶还原法可以快速、方便的检测曝气生物滤池中陶粒负载生物膜的生物活性,并能很好的进行定量化测定.%The biofilms activity in Biological Aerated Filters (BAF) is quantitatively determined by 2,3,5-triphenyl tetrazolium chloride (TTC) -dehydrogenase assay and some major factors influencing the determination are studied in this paper. The optimum parameters are shown as follows: Tris-HCl buffers and 8. 0 of pH, 0. 4% ( mass fraction) of TTC and 0. 1 mol/L of dextrose solution. The incubation time and temperature are 4 h and 401 , respectively. The formazan reduction product can be efficiently extracted by methylbenzene, which can reduce the disturbance of dye color. This study demonstrates that the TTC-dehydrogenase assay can be successfully applied to the determination of biofilms activity in BAF.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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%.

  1. Radioactive contamination of BaF2 crystal scintillator

    CERN Document Server

    Polischuk, O G; Bernabei, R; Cappella, F; Caracciolo, V; Cerulli, R; Di Marco, A; Danevich, F A; Incicchitti, A; Poda, D V; Tretyak, V I

    2013-01-01

    Barium fluoride (BaF$_2$) crystal scintillators are promising detectors to search for double beta decay processes in $^{130}$Ba ($Q_{2{\\beta}}$ = 2619(3) keV) and $^{132}$Ba ($Q_{2{\\beta}}$ = 844(1) keV). The $^{130}$Ba isotope is of particular interest because of the indications on 2${\\beta}$ decay found in two geochemical experiments. The radioactive contamination of BaF$_2$ scintillation crystal with mass of 1.714 kg was measured over 113.4 hours in a low-background DAMA/R&D set-up deep underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN (LNGS, Italy). The half-life of $^{212}$Po (present in the crystal scintillator due to contamination by radium) was estimated as $T_{1/2}$ = 298.8 $\\pm$ 0.8(stat.) $\\pm$ 1.4(syst.) ns by analysis of the events pulse profiles.

  2. 7SK-BAF axis controls pervasive transcription at enhancers.

    Science.gov (United States)

    Flynn, Ryan A; Do, Brian T; Rubin, Adam J; Calo, Eliezer; Lee, Byron; Kuchelmeister, Hannes; Rale, Michael; Chu, Ci; Kool, Eric T; Wysocka, Joanna; Khavari, Paul A; Chang, Howard Y

    2016-03-01

    RNA functions at enhancers remain mysterious. Here we show that the 7SK small nuclear RNA (snRNA) inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome wide in mouse and human cells, and it is required to limit enhancer-RNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription and DNA-damage signaling. 7SK physically interacts with the BAF chromatin-remodeling complex, recruits BAF to enhancers and inhibits enhancer transcription by modulating chromatin structure. In turn, 7SK occupancy at enhancers coincides with that of Brd4 and is exquisitely sensitive to the bromodomain inhibitor JQ1. Thus, 7SK uses distinct mechanisms to counteract the diverse consequences of pervasive transcription that distinguish super enhancers, enhancers and promoters.

  3. baf(x)dx=∫baf(a+b-x)dx的应用初探%Exploration of the Application of ∫baf(x) dx = ∫baf(a+ b - x ) dx

    Institute of Scientific and Technical Information of China (English)

    吴琼

    2003-01-01

    本文从两个方面对等式∫baf(x)dx=∫bafa+b-x)dx的应用做了一些初步探讨,这两方面分别为:运用这个等式证明一些积分等式,以及证明一些不易求解的三角函数积分.

  4. BaF2 TIME DIFFERENTIAL PERTURBED ANGULAR DISTRIBUTION SPECTROMETER

    Institute of Scientific and Technical Information of China (English)

    朱升云; 勾振辉; 等

    1994-01-01

    A BaF2 time differential perturbed angular distribution spectrometer has been established at the HI-13 tandem accelerator in CIAE.The time resolution of the spectrometer is 195ps and the nonlinearity is less than 2%.The spectrometer works very stably and no time drift is found over a period of experimental runs.This spectrometer has been successfully used in the g-factor measurement of 43Sc(19/2-,3.1232MeV).

  5. 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.

  6. Fenton/BAF组合工艺处理全棉机织布印染废水研究%Fenton Oxidation/BAF Process for Advanced Treatment of Wastewater from Dyeing and Finishing of Cotton Woven Fabrics

    Institute of Scientific and Technical Information of China (English)

    文淦斌; 黄瑞敏; 黄春梅; 王君

    2011-01-01

    The dyeing and finishing processes of cotton woven fabrics need a lot of sizing agents toimprove the smoothness and wear resistance of the fabrics, thus the discharged wastewater often contains a lot of desizing wastewater, which has high concentration of COD, strong alkalinity and poor biodegradability. The biodegradability is difficult to be improved using conventional coagulation sedimentation/anaerobic/aerobic process, and the effluent COD and color are difficult to meet the standards. According to the characteristics above, the combined process of Fenton oxidation and biological aerated filter (BAF) was used for the advanced treatment. The results of the pilot study show that under the conditions of initial pH of 4, H2O2 dosage of 150 mg/L, Fe2+/H2O2 ratio of 1 and reaction time of 60 min in Fenton oxidation process, COD and color of the wastewater are reduced from 400 mg/L to 125 mg/L with the removal rate of 68.75% and from 200 times to less than 25 times respectively. After the Fenton oxidation,the B/C ratio is increased from 0.08 to 0.34, and the biodegradability is significantly improved. Under the condition of HRT of 2.5 h, COD in the effluent from BAF is 74.5 mg/L, with the removal rate of 40.4%. After treatment by the combined process, the removal rate of COD is more than 80% , and the color is less than 25 times, with good treatment efficiency.%全棉机织布染色加工需使用大量浆料助剂进行上浆处理以提高织物的光滑度及耐磨性,因而排放的废水中往往含有大量的退浆废水,其COD浓度高、碱度强、可生化性差,经常规的混凝沉淀/厌氧/好氧组合工艺处理后,可生化性难以改善,出水COD、色度值难以达标.采用Fen-ton/曝气生物滤池(BAF)组合工艺对其进行深度处理,中试结果表明,在Fenton工艺的初始pH值=4、H2O2投加量=150 mg/L、Fe2+/H2O2值=1、反应时间为60 min的条件下,COD由原来的400mg/L降低至125 mg/L,去除率达68.75%,色度由200

  7. mSWI/SNF (BAF) Complexes Are Indispensable for the Neurogenesis and Development of Embryonic Olfactory Epithelium.

    Science.gov (United States)

    Bachmann, Christina; Nguyen, Huong; Rosenbusch, Joachim; Pham, Linh; Rabe, Tamara; Patwa, Megha; Sokpor, Godwin; Seong, Rho H; Ashery-Padan, Ruth; Mansouri, Ahmed; Stoykova, Anastassia; Staiger, Jochen F; Tuoc, Tran

    2016-09-01

    Neurogenesis is a key developmental event through which neurons are generated from neural stem/progenitor cells. Chromatin remodeling BAF (mSWI/SNF) complexes have been reported to play essential roles in the neurogenesis of the central nervous system. However, whether BAF complexes are required for neuron generation in the olfactory system is unknown. Here, we identified onscBAF and ornBAF complexes, which are specifically present in olfactory neural stem cells (oNSCs) and olfactory receptor neurons (ORNs), respectively. We demonstrated that BAF155 subunit is highly expressed in both oNSCs and ORNs, whereas high expression of BAF170 subunit is observed only in ORNs. We report that conditional deletion of BAF155, a core subunit in both onscBAF and ornBAF complexes, causes impaired proliferation of oNSCs as well as defective maturation and axonogenesis of ORNs in the developing olfactory epithelium (OE), while the high expression of BAF170 is important for maturation of ORNs. Interestingly, in the absence of BAF complexes in BAF155/BAF170 double-conditional knockout mice (dcKO), OE is not specified. Mechanistically, BAF complex is required for normal activation of Pax6-dependent transcriptional activity in stem cells/progenitors of the OE. Our findings unveil a novel mechanism mediated by the mSWI/SNF complex in OE neurogenesis and development.

  8. 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...

  9. The new readout electronics for the BaF2-calorimeter TAPS

    NARCIS (Netherlands)

    Drexler, P; Thoring, U; Bonn, W; van der Duin, HAP; Holzmann, R; van der Kruk, G; Krusche, B; Lohner, H; Metag, [No Value; Nijboer, TW; Novotny, R; Potapov, A; Salz, C; Schadmand, S; Steinacher, M; Thiel, M; Vorenholt, H

    2003-01-01

    A highly compact and fast VME based readout board for BaF2 scintillation detectors has been designed, developed, and finally tested in an in-beam experiment. Adapted to the excellent properties of BaF2, the unit allows to digitize time, energy, and pulse-shape information of four detector channels i

  10. BAF200 is required for heart morphogenesis and coronary artery development.

    Directory of Open Access Journals (Sweden)

    Lingjuan He

    Full Text Available ATP-dependent SWI/SNF chromatin remodeling complexes utilize ATP hydrolysis to non-covalently change nucleosome-DNA interactions and are essential in stem cell development, organogenesis, and tumorigenesis. Biochemical studies show that SWI/SNF in mammalian cells can be divided into two subcomplexes BAF and PBAF based on the subunit composition. ARID2 or BAF200 has been defined as an intrinsic subunit of PBAF complex. However, the function of BAF200 in vivo is not clear. To dissect the possible role of BAF200 in regulating embryogenesis and organ development, we generated BAF200 mutant mice and found they were embryonic lethal. BAF200 mutant embryos exhibited multiple cardiac defects including thin myocardium, ventricular septum defect, common atrioventricular valve, and double outlet right ventricle around E14.5. Moreover, we also detected reduced intramyocardial coronary arteries in BAF200 mutants, suggesting that BAF200 is required for proper migration and differentiation of subepicardial venous cells into arterial endothelial cells. Our work revealed that PBAF complex plays a critical role in heart morphogenesis and coronary artery angiogenesis.

  11. 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

  12. 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.

  13. 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.

  14. A unique missense allele of BAF155, a core BAF chromatin remodeling complex protein, causes neural tube closure defects in mice.

    Science.gov (United States)

    Harmacek, Laura; Watkins-Chow, Dawn E; Chen, Jianfu; Jones, Kenneth L; Pavan, William J; Salbaum, J Michael; Niswander, Lee

    2014-05-01

    Failure of embryonic neural tube closure results in the second most common class of birth defects known as neural tube defects (NTDs). While NTDs are likely the result of complex multigenic dysfunction, it is not known whether polymorphisms in epigenetic regulators may be risk factors for NTDs. Here we characterized Baf155(msp3) , a unique ENU-induced allele in mice. Homozygous Baf155(mps3) embryos exhibit highly penetrant exencephaly, allowing us to investigate the roles of an assembled, but malfunctional BAF chromatin remodeling complex in vivo at the time of neural tube closure. Evidence of defects in proliferation and apoptosis were found within the neural tube. RNA-Seq analysis revealed that surprisingly few genes showed altered expression in Baf155 mutant neural tissue, given the broad epigenetic role of the BAF complex, but included genes involved in neural development and cell survival. Moreover, gene expression changes between individual mutants were variable even though the NTD was consistently observed. This suggests that inconsistent gene regulation contributes to failed neural tube closure. These results shed light on the role of the BAF complex in the process of neural tube closure and highlight the importance of studying missense alleles to understand epigenetic regulation during critical phases of development.

  15. 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.

  16. 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.

  17. Vibrational spectra of (BaF2)n (n=1-6) clusters

    Science.gov (United States)

    Pandey, Ratnesh K.; Waters, Kevin; Nigam, Sandeep; Pandey, Ravindra; Pandey, Avinash C.

    2016-05-01

    The vibrational properties of alkaline-earth metal fluoride clusters (BaF2)n (n=1-6) are investigated in the framework of density functional theory. The calculated Raman and Infrared (IR) spectra reveals shift in Raman and IR peak position towards lower frequency region with the increase in the cluster size. Further the calculated spectra have been compared with the experimental vibrational spectra of bulk BaF2 crystal. Even though the smaller size cluster lacks translational symmetry, the structural and vibrational characteristic of (BaF2)5-6 are nearer to bulk counterpart.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 臭氧 BAF一体化装置处理含氨氮有机污染废水%Integrated Unit of Ozone-BAF System for Treatment of Organic Polluted Wastewater with Ammonia Nitrogen

    Institute of Scientific and Technical Information of China (English)

    刘剑玉; 林庆坤; 汪晓军

    2015-01-01

    Integrated unit of ozone and biological aerated filter (BAF)was used to treat organic polluted wastewater containing ammonia nitrogen. The results indicate that removal rate of ammonia nitrogen decreases with the increase of ammonia nitrogen concentration in influent,the ideal ammonia nitrogen loading is 0. 17 ~ 0. 25 kg / m3 ·d,and then removal rate of ammonia nitrogen can be above 60% stably. Ammonia nitrogen in influent has some negative influence on COD removal. When concentration of ammonia nitrogen is more than 60 mg / L,effect of COD removal turns worse obviously. Lipid-phosphorous method was applied in biomass measurement of the integrated ozone-BAF unit to treat biomass distribution in the system. It is shown that in the area near inlet,when sampling height isn’t more than 1. 2 m,biomass is extremely rare as a result of the high ozone disinfection. Biomass reaches maximum when the vertical distance is 1. 5 m,and then biomass declines with the increase of sampling height.%该文采用臭氧曝气生物滤池(BAF)一体化装置处理含氨氮有机污染废水。随着氨氮浓度增大,系统对氨氮的去除率呈现下降趋势,较理想的进水氨氮负荷范围为0.17~0.25 kg / m3·d,此时的氨氮去除率可稳定在60%以上。进水中含有的氨氮对COD去除效果的影响较大,当氨氮浓度超过60 mg / L时,系统对 COD的去除效果明显变差。用脂磷法测定一体化装置内的微生物量,结果显示在距离进水口较近的区域(取样高度≤1.2 m)由于高浓度臭氧的杀菌作用,微生物量极少;在距离进水口垂直距离1.5 m处生物量达到最大值,形成了臭氧氧化和生化的协同作用区域;在此之后,随着取样高度的继续增加,系统内生物量出现下降的现象。

  4. The BAH domain of BAF180 is required for PCNA ubiquitination

    Energy Technology Data Exchange (ETDEWEB)

    Niimi, Atsuko [Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Hopkins, Suzanna R; Downs, Jessica A [Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ (United Kingdom); Masutani, Chikahide, E-mail: masutani@riem.nagoya-u.ac.jp [Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

    2015-09-15

    Highlights: • The expression of BAF180 promotes UV-induced PCNA ubiquitination during S phase. • The BAH domains of BAF180 alone are sufficient to promote PCNA ubiquitination. • The BAH domains are not assembled into the PBAF in the absence of the C-terminus. - Abstract: Monoubiquitination of proliferating cell nuclear antigen (PCNA) is a critical regulator of post replication repair (PRR). The depletion of BAF180, a unique subunit of the PBAF chromatin remodeling complex in human cells results in reduced PCNA ubiquitination leading to less efficient fork progression following DNA damage, but little is known about the mechanism. Here, we report that the expression of exogenous BAF180 in cells promotes PCNA ubiquitination during S-phase after UV irradiation and it persists for many hours. No correlation was observed between the protein level of ubiquitin-specific protease 1 (USP1) and ubiquitinated PCNA in BAF180 expressing cells. Analysis of cells expressing BAF180 deletion mutants showed that the bromo-adjacent homology (BAH) domains are responsible for this effect. Surprisingly, a deletion construct encoding only the BAH domain region is able to increase the level of ubiquitinated PCNA, even though it is unable to be assembled into the PBAF complex. These results suggest that the ATPase-dependent chromatin remodeling activity of PBAF is not necessary, but instead the BAH domains are sufficient to promote PCNA ubiquitination.

  5. Luminescence and scintillation properties of BaF2sbnd Ce transparent ceramic

    Science.gov (United States)

    Luo, Junming; Sahi, Sunil; Groza, Michael; Wang, Zhiqiang; Ma, Lun; Chen, Wei; Burger, Arnold; Kenarangui, Rasool; Sham, Tsun-Kong; Selim, Farida A.

    2016-08-01

    Cerium doped Barium Fluoride (BaF2sbnd Ce) transparent ceramic was fabricated and its luminescence and scintillation properties were studied. The photoluminescence shows the emission peaks at 310 nm and 323 nm and is related to the 5d-4f transitions in Ce3+ ion. Photo peak at 511 keV and 1274 keV were obtained with BaF2sbnd Ce transparent ceramic for Na-22 radioisotopes. Energy resolution of 13.5% at 662 keV is calculated for the BaF2sbnd Ce transparent ceramic. Light yield of 5100 photons/MeV was recorded for BaF2sbnd Ce(0.2%) ceramic and is comparable to its single crystal counterpart. Scintillation decay time measurements shows fast component of 58 ns and a relatively slow component of 434 ns under 662 keV gamma excitation. The slower component in BaF2sbnd Ce(0.2%) ceramic is about 200 ns faster than the STE emission in BaF2 host and is associated with the dipole-dipole energy transfer from the host matrix to Ce3+ luminescence center.

  6. 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 ...

  7. 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.

  8. 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.

  9. Context-dependent role for chromatin remodeling component PBRM1/BAF180 in clear cell renal cell carcinoma

    Science.gov (United States)

    Murakami, A; Wang, L; Kalhorn, S; Schraml, P; Rathmell, W K; Tan, A C; Nemenoff, R; Stenmark, K; Jiang, B-H; Reyland, M E; Heasley, L; Hu, C-J

    2017-01-01

    A subset of clear cell renal cell carcinoma (ccRCC) tumors exhibit a HIF1A gene mutation, yielding two ccRCC tumor types, H1H2 type expressing both HIF1α and HIF2α, and H2 type expressing HIF2α, but not functional HIF1α protein. However, it is unclear how the H1H2 type ccRCC tumors escape HIF1's tumor-suppressive activity. The polybromo-1 (PBRM1) gene coding for the BAF180 protein, a component of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex, is inactivated in 40% ccRCCs, the function and mechanism of BAF180 mutation is unknown. Our previous study indicates that BAF180-containing SWI/SNF chromatin remodeling complex is a co-activator for transcription factor HIF to induce HIF target genes. Thus, our questions are if BAF180 is involved in HIF-mediated hypoxia response and if PBRM1/BAF180 mutation has any association with the HIF1A retention in H1H2 type ccRCC. We report here that BAF180 is mutated in H1H2 ccRCC cell lines and tumors, and BAF180 re-expression in H1H2 ccRCC cell lines reduced cell proliferation/survival, indicating that BAF180 has tumor-suppressive role in these cells. However, BAF180 is expressed in HIF1-deficient H2 ccRCC cell lines and tumors, and BAF180 knockdown in H2 type ccRCC cell lines reduced cell proliferation/survival, indicating that BAF180 has tumor-promoting activity in these cells. In addition, our data show that BAF180 functions as co-activator for HIF1- and HIF2-mediated transcriptional response, and BAF180's tumor-suppressive and -promoting activity in ccRCC cell lines depends on co-expression of HIF1 and HIF2, respectively. Thus, our studies reveal that BAF180 function in ccRCC is context dependent, and that mutation of PBRM1/BAF180 serves as an alternative strategy for ccRCC tumors to reduce HIF1 tumor-suppressive activity in H1H2 ccRCC tumors. Our studies define distinct functional subgroups of ccRCCs based on expression of BAF180, and suggest that BAF180 inhibition may be a novel therapeutic

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. Molecular Dynamics Simulations for Melting Temperatures of SrF2and BaF2

    Institute of Scientific and Technical Information of China (English)

    Xiao-yu Huang; Xin-lu Cheng; Chao-lei Fan; Qiong Chen; Xiao-li Yuan

    2009-01-01

    The shell-model molecular dynamics method was applied to simulate the melting temper-atures of SrF2 and BaF2 at elevated temperatures and high pressures. The same method was used to calculate the equations of state for SrF2 and BaF2 over the pressure range of 0.1 MPa-3 GPa and 0.1 MPa-7 GPa. Compared with previous results for equations of state, the maximum errors are 0.3% and 2.2%, respectively. Considering the pre-melting in the fluorite-type crystals, we made the necessary corrections for the simulated melting temper-atures of SrF2 and BaF2. Consequently, the melting temperatures of SrF2 and BaF2 were obtained for high pressures. The melting temperatures of SrF2 and BaF2 that were obtained by the simulation are in good agreement with available experimental data.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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...

  1. 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.

  2. Luminescent and kinetic properties of the polystyrene composites based on BaF2 nanoparticles

    Science.gov (United States)

    Demkiv, T. M.; Halyatkin, O. O.; Vistovskyy, V. V.; Gektin, A. V.; Voloshinovskii, A. S.

    2016-02-01

    Luminescence-kinetic properties of polystyrene composites based on BaF2 nanoparticles were studied. The electron emission from the nanoparticles due to the photoelectric effect is the main luminescence excitation mechanism in the case of polystyrene composites loaded with small BaF2 nanoparticles (~20 nm). Scintillation pulse of polystyrene composites possesses only fast decay component with the time constant τ~2 ns, and its emission intensity considerably exceeds the one for pure polystyrene scintillator upon the X-ray excitations.

  3. Loss of BAF (mSWI/SNF Complexes Causes Global Transcriptional and Chromatin State Changes in Forebrain Development

    Directory of Open Access Journals (Sweden)

    Ramanathan Narayanan

    2015-12-01

    Full Text Available BAF (Brg/Brm-associated factors complexes play important roles in development and are linked to chromatin plasticity at selected genomic loci. Nevertheless, a full understanding of their role in development and chromatin remodeling has been hindered by the absence of mutants completely lacking BAF complexes. Here, we report that the loss of BAF155/BAF170 in double-conditional knockout (dcKO mice eliminates all known BAF subunits, resulting in an overall reduction in active chromatin marks (H3K9Ac, a global increase in repressive marks (H3K27me2/3, and downregulation of gene expression. We demonstrate that BAF complexes interact with H3K27 demethylases (JMJD3 and UTX and potentiate their activity. Importantly, BAF complexes are indispensable for forebrain development, including proliferation, differentiation, and cell survival of neural progenitor cells. Our findings reveal a molecular mechanism mediated by BAF complexes that controls the global transcriptional program and chromatin state in development.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. In-Situ Conductivity Measurement of BaF2 under High Pressure and High Temperature

    Institute of Scientific and Technical Information of China (English)

    HAO Ai-Min; LI Xiao-Dong; LIU Jing; GAO Chun-Xiao; LI Ming; HE Chun-Yuan; HUANG Xiao-Wei; ZHANG Dong-Mei; YU Cui-Ling; ZOU Guang-Tian; LI Yan-Chun

    2006-01-01

    @@ We perform the in-situ conductivity measurement on BaF2 at high pressure using a microcircuit fabricated on a diamond anvil cell. The results show that BaF2 initially exhibits the electrical property of an insulator at pressure below 25 Gpa, it transforms to a wide energy gap semiconductor at pressure from 25 to 30 Gpa, and the conductivity increases gradually with increasing pressure from 30 Gpa. However, the metallization predicted by theoretical calculation at 30-33 Gpa cannot be observed. In addition, we measure the temperature dependence of the conductivity at several pressures and obtain the relationship between the energy gap and pressure. Based on the experimental data, it is predicted that BaF2 would transform to a metal at about 87 Gpa and ambient temperature. The conductivity of BaF2 reaches the order of 10-3Ω-1 cm-1 at 37 Gpa and 2400 K, the superionic conduction is not observed during the experiments, indicating the application of pressure elevates greatly the transition temperature of the superionic conduction.

  10. Response of BaF sub 2 and YAP:Ce to heavy ions

    CERN Document Server

    Klamra, W; Moszynski, M; Norlin, L O; Novák, D; Possnert, G

    2000-01-01

    The light output and energy resolution for BaF sub 2 and YAP:Ce have been measured with sup 1 sup 6 O, sup 3 sup 5 Cl and sup 7 sup 9 Br in the energy region 8.5-34 MeV. Both crystals show a nonproportional light yield response, mostly pronounced for the lighter ions.

  11. X-RAY AND GAMMA-RAY LUMINESCENCE OF CE-3+ DOPED BAF2 CRYSTALS

    NARCIS (Netherlands)

    DORENBOS, P; VISSER, R; VANEIJK, CWE; HOLLANDER, RW; DENHARTOG, HW

    1991-01-01

    The scintillation properties of BaF2 doped with 0.002 to 10 mol% Ce3+ have been studied by means of X-ray and gamma ray excitation. The luminescence intensity increases with the Ce concentration until a maximum is reached for 0.2 mol% doped crystals. The light yield is then about 60% more intense th

  12. Clock distribution for BaF2 readout electronics at CSNS-WNS

    Science.gov (United States)

    He, Bing; Cao, Ping; Zhang, De-Liang; Wang, Qi; Zhang, Ya-Xi; Qi, Xin-Cheng; An, Qi

    2017-01-01

    A BaF2 (Barium Fluoride) detector array is designed to precisely measure the (n, γ) cross section at the CSNS-WNS (white neutron source at China Spallation Neutron Source). It is a 4π solid angle-shaped detector array consisting of 92 BaF2 crystal elements. To discriminate signals from the BaF2 detector, a pulse shape discrimination method is used, supported by a waveform digitization technique. There are 92 channels for digitizing. The precision and synchronization of clock distribution restricts the performance of waveform digitizing. In this paper, a clock prototype for the BaF2 readout electronics at CSNS-WNS is introduced. It is based on the PXIe platform and has a twin-stage tree topology. In the first stage, clock is synchronously distributed from the tree root to each PXIe crate through a coaxial cable over a long distance, while in the second stage, the clock is further distributed to each electronic module through a PXIe dedicated differential star bus. With the help of this topology, each tree node can fan out up to 20 clocks with 3U size. Test results show the clock jitter is less than 20 ps, which meets the requirements of the BaF2 readout electronics. Besides, this clock system has the advantages of high density, simplicity, scalability and cost saving, so it can be useful for other clock distribution applications. Supported by National Research and Development plan (2016 YFA0401602) NSAF (U1530111) and National Natural Science Foundation of China (11005107)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Suppression of HPV E6 and E7 expression by BAF53 depletion in cervical cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kiwon; Lee, Ah-Young [Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of); Kwon, Yunhee Kim [Department of Life and Nanopharmaceutical Science and Department of Biology, Kyunghee University, Seoul 130-701 (Korea, Republic of); Kwon, Hyockman, E-mail: hmkwon@hufs.ac.kr [Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of)

    2011-08-26

    Highlights: {yields} Integration of HPV into host genome critical for activation of E6 and E7 oncogenes. {yields} BAF53 is essential for higher-order chromatin structure. {yields} BAF53 knockdown suppresses E6 and E7 from HPV integrants, but not from episomal HPVs. {yields} BAF53 knockdown decreases H3K9Ac and H4K12Ac on P105 promoter of integrated HPV 18. {yields} BAF53 knockdown restores the p53-dependent signaling pathway in HeLa and SiHa cells. -- Abstract: Deregulation of the expression of human papillomavirus (HPV) oncogenes E6 and E7 plays a pivotal role in cervical carcinogenesis because the E6 and E7 proteins neutralize p53 and Rb tumor suppressor pathways, respectively. In approximately 90% of all cervical carcinomas, HPVs are found to be integrated into the host genome. Following integration, the core-enhancer element and P105 promoter that control expression of E6 and E7 adopt a chromatin structure that is different from that of episomal HPV, and this has been proposed to contribute to activation of E6 and E7 expression. However, the molecular basis underlying this chromatin structural change remains unknown. Previously, BAF53 has been shown to be essential for the integrity of higher-order chromatin structure and interchromosomal interactions. Here, we examined whether BAF53 is required for activated expression of E6 and E7 genes. We found that BAF53 knockdown led to suppression of expression of E6 and E7 genes from HPV integrants in cervical carcinoma cell lines HeLa and SiHa. Conversely, expression of transiently transfected HPV18-LCR-Luciferase was not suppressed by BAF53 knockdown. The level of the active histone marks H3K9Ac and H4K12Ac on the P105 promoter of integrated HPV 18 was decreased in BAF53 knockdown cells. BAF53 knockdown restored the p53-dependent signaling pathway in HeLa and SiHa cells. These results suggest that activated expression of the E6 and E7 genes of integrated HPV is dependent on BAF53-dependent higher-order chromatin

  20. Geomatics for Smart Cities: Obtaining the Urban Planning Baf Index from Existing Digital Maps

    Science.gov (United States)

    Casella, V.; Franzini, M.; De Lotto, R.

    2016-06-01

    The urban analytics expression is spreading out. To our understanding, it deals with the capability of measuring cities and their communities, as a support to their effective planning and management. In other words, being an analytically well-known city is a precondition for pursuing smartness. Urban planning is a very important item for city management and is interrelated with many layers, including urban environmental quality, air quality and well-being. Effective urban planning is based on the knowledge of quantitative parameters such as the biotope area factor (BAF), which was originally proposed for the city of Berlin and is currently used in other cities. The BAF index is used to evaluate the degree of soil permeability and measures, to a certain extent and from a specific point of view, how a city is eco-friendly. The usual way of evaluating the BAF is based on the manual construction of dedicated maps, using existing orthophotos and oblique imagery as a support. But this method is expensive, time-consuming and non-objective, as it is prone to different interpretations. The paper presents a newly-developed methodology for calculating the BAF. It is based on the use of existing digital cartography and on the application of geoprocessing techniques from GIS science: it is therefore fully automated and objective. The Pavia city (Northern Italy) is used as a testsite and a careful validation of the developed methodology is carried out, by comparison to 12 manually surveyed test areas, corresponding to 5% of the built-up areas of the municipality.

  1. A BaF2 crystal array for high energy -ray measurements

    Indian Academy of Sciences (India)

    A Ray; S R Banerjee; P Das

    2001-07-01

    We shall discuss about the scientific motivation and construction of a 7 × 7 BaF2 crystal array at Variable Energy Cyclotron Centre, Calcutta. This detector would be used to measure high energy -ray photons from GDR decay and proton–neutron bremsstrahlung reactions at the present 88'' cyclotron and upcoming superconducting cyclotron at VECC, Calcutta. This detector can also be used to measure photons from quark–gluon plasma at the relativistic heavy ion collider (RHIC) in USA.

  2. Beber e dirigir: características de condutores com bafômetro positivo

    Directory of Open Access Journals (Sweden)

    Valdir Ribeiro Campos

    2012-01-01

    Full Text Available CONTEXTO: O beber e dirigir não foi suficientemente estudado no Brasil até agora. OBJETIVO: Apresentar dados do primeiro levantamento sobre o comportamento do beber e dirigir de um estado do Brasil. MÉTODO: Foram conduzidas 1.799 entrevistas anônimas com motoristas em postos de checagem de sobriedade em 10 cidades, representando as 10 regiões geográficas do estado de Minas Gerais. Desses motoristas, 1.209 (67,2% responderam a um questionário estruturado e aceitaram o teste do bafômetro. RESULTADOS: Vinte por cento dos motoristas estavam dirigindo com níveis de alcoolemia acima do limite legal. A análise de regressão logística, controlada por sexo, foi utilizada para predizer bafômetro positivo. Essa análise mostrou chance aumentada de bafômetro positivo para condutor com idade acima de 31 anos que tem frequência de consumo de álcool de, pelo menos, um a dois dias na semana e para quem não usa o cinto de segurança. CONCLUSÃO: Estudos localizados com metodologia similares realizados em postos de checagem da sobriedade podem monitorar o comportamento dos condutores e os riscos no trânsito e direcionar políticas públicas sobre o beber e dirigir.

  3. Clock Distributing for BaF2 Readout Electronics at CSNS-WNS

    CERN Document Server

    He, Bing; De-Liang-Zhang,; Wang, Qi; Zhang, Ya-Xi; Qi, Xin-Cheng; Qi-An,

    2016-01-01

    aF2 (Barium Fluoride) detector array is designed for the measurement of (n,{\\gamma}) cross section precisely at CSNS-WNS (white neutron source at China Spallation Neutron Source). It is a 4{\\pi}solid angle-shaped detector array consisting of 92 BaF2 crystal elements. To discriminate signals from BaF2 detector, pulse shape discrimination methodology is used, which is supported by waveform digitization technique. There are total 92 channels for digitizing. The precision and synchronization of clock distribution restricts the performance of waveform digitizing. In this paper, the clock prototype for BaF2 readout electronics at CSNS-WNS is introduced. It is based on PXIe platform and has a twin-stage tree topology. In the first stage, clock is distributed from the tree root to each PXIe crate synchronously through coaxial cable over long distance, while in the second stage, clock is further distributed to each electronic module through PXIe dedicated differential star bus. With the help of this topology, each tre...

  4. BAF53 Forms Distinct Nuclear Complexes and Functions as a Critical c-Myc-Interacting Nuclear Cofactor for Oncogenic Transformation

    Science.gov (United States)

    Park, Jeonghyeon; Wood, Marcelo A.; Cole, Michael D.

    2002-01-01

    The c-Myc oncoprotein functions as a transcription factor that can transform normal cells into tumor cells, as well as playing a direct role in normal cell proliferation. The c-Myc protein transactivates cellular promoters by recruiting nuclear cofactors to chromosomal sites through an N-terminal transactivation domain. We have previously reported the identification and functional characterization of four different c-Myc cofactors: TRRAP, hGCN5, TIP49, and TIP48. Here we present the identification and characterization of the actin-related protein BAF53 as a c-Myc-interacting nuclear cofactor that forms distinct nuclear complexes. In addition to the human SWI/SNF-related BAF complex, BAF53 forms a complex with TIP49 and TIP48 and a separate biochemically distinct complex containing TRRAP and a histone acetyltransferase which does not contain TIP60. Using deletion mutants of BAF53, we show that BAF53 is critical for c-Myc oncogenic activity. Our results indicate that BAF53 plays a functional role in c-Myc-interacting nuclear complexes. PMID:11839798

  5. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. Structure, branching ratios, and a laser-cooling scheme for the 138BaF molecule

    Science.gov (United States)

    Chen, Tao; Bu, Wenhao; Yan, Bo

    2016-12-01

    For laser-cooling considerations, we have theoretically investigated the electronic, rovibrational, and hyperfine structures of the BaF molecule. The highly diagonal Franck-Condon factors and the branching ratios for all possible transitions within the lowest-lying four electronic states have also been calculated. Meanwhile, the mixing between the metastable A'2Δ and A2Π states and, further, the lifetime of the Δ state have been estimated since the loss procedure via the Δ state might fatally break the main quasicycling Σ -Π transition for cooling and trapping. The resultant hyperfine splittings of each rovibrational state in the X2Σ+ state provide benchmarks for sideband modulations of the cooling and repumping lasers and the remixing microwaves to address all necessary levels. The calculated Zeeman shift and g factors for both X and A states serve as benchmarks for selection of the trapping laser polarizations. Our study paves the way for future laser cooling and magneto-optical trapping of the BaF molecule.

  17. Small Molecule Inhibitors of BAF; A Promising Family of Compounds in HIV-1 Latency Reversal

    Directory of Open Access Journals (Sweden)

    Mateusz Stoszko

    2016-01-01

    Full Text Available Persistence of latently infected cells in presence of Anti-Retroviral Therapy presents the main obstacle to HIV-1 eradication. Much effort is thus placed on identification of compounds capable of HIV-1 latency reversal in order to render infected cells susceptible to viral cytopathic effects and immune clearance. We identified the BAF chromatin remodeling complex as a key player required for maintenance of HIV-1 latency, highlighting its potential as a molecular target for inhibition in latency reversal. Here, we screened a recently identified panel of small molecule inhibitors of BAF (BAFi's for potential to activate latent HIV-1. Latency reversal was strongly induced by BAFi's Caffeic Acid Phenethyl Ester and Pyrimethamine, two molecules previously characterized for clinical application. BAFi's reversed HIV-1 latency in cell line based latency models, in two ex vivo infected primary cell models of latency, as well as in HIV-1 infected patient's CD4+ T cells, without inducing T cell proliferation or activation. BAFi-induced HIV-1 latency reversal was synergistically enhanced upon PKC pathway activation and HDAC-inhibition. Therefore BAFi's constitute a promising family of molecules for inclusion in therapeutic combinatorial HIV-1 latency reversal.

  18. Hardness of CaF2 and BaF2 solid lubricants at 25 to 670 deg C

    Science.gov (United States)

    Deadmore, Daniel L.; Sliney, Harold E.

    1987-01-01

    Plastic deformation is a prominent factor in determining the lubricating value of solid lubricants. Little information is available and its direct measurement is difficult so hardness, which is an indirect measure of this property was determined for fluoride solid lubricant compositions. The Vickers hardness of BaF2 and CaF2 single crystals was measured up to 670 C in a vacuum. The orientation of the BaF2 was near the (013) plane and the CaF2 was about 16 degrees from the degrees from the (1'11) plane. The BaF2 has a hardness of 83 kg/sq mm at the 25 C and 9 at the 600 C. The CaF2 is 170 at 25 C and 13 at 670 C. The decrease in hardness in the temperature range of 25 to 100 C is very rapid and amounts to 40% for both materials. Melts of BaF2 and CaF2 were made in a platinum crucible in ambient air with compositions of 50 to 100 wt% BaF2. The Vickers hardness of these polycrystalline binary compositions at 25 C increased with increasing CaF2 reaching a maximum of 150 kn/sq mm near the eutectic. The polycrystalline CaF2 was 14% softer than that of the single crystal surface and BsF2 was 30% harder than the single crystal surface. It is estimated that the brittle to ductile transition temperature for CaF2 and BaF2 is less than 100 C for the conditions present in the hardness tester.

  19. 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.

  20. 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...

  1. 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.

  2. Fenton-BAF-RO工艺处理电镀前处理废水并回用%Treatment and Reuse of Electroplating Pre-treatment Wastewater by Fenton/BAF/RO Membrane Technology

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Pre-treatment wastewater is an important part of the plating wastewater. It has higher COD but with relatively larger reuse potential. The technology of Fenton-BAF-RO membrane separation process was used to treat electroplating Pre-treatment wastewater from a plant in Guangdong province, the results show that the pre-treatment wastewater can be advanced treated and reused effectively by this technology, and by concentrated water recirculation, zero emission was achieved. Fenton-BAF process ensure the stable operation of the RO system.%  前处理废水是电镀废水的重要组成部分,COD较高但回用潜力相对较大。采用Fenton-BAF-RO膜分离工艺处理广东省某厂电镀前处理废水,运行结果表明,该工艺可有效实现电镀前处理废水的深度处理及回用,并且通过浓水回流达到零排放,Fenton-BAF 工艺保证了 RO 系统的稳定运行。

  3. 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.

  4. 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.

  5. Familial partial lipodystrophy, mandibuloacral dysplasia and restrictive dermopathy feature barrier-to-autointegration factor (BAF) nuclear redistribution.

    Science.gov (United States)

    Capanni, Cristina; Squarzoni, Stefano; Cenni, Vittoria; D'Apice, Maria Rosaria; Gambineri, Alessandra; Novelli, Giuseppe; Wehnert, Manfred; Pasquali, Renato; Maraldi, Nadir M; Lattanzi, Giovanna

    2012-10-01

    Prelamin A processing impairment is a common feature of a restricted group of rare genetic alterations/disorders associated with a wide range of clinical phenotypes. Changes in histone posttranslational modifications, alterations in non-histone chromatin proteins and chromatin disorganization have been specifically linked to impairment of specific, distinct prelamin A processing steps, but the molecular mechanism involved in these processes is not yet understood . In this study, we show that the accumulation of wild-type prelamin A detected in restrictive dermopathy (RD), as well as the accumulation of mutated forms of prelamin A identified in familial partial lipodystrophy (FPLD) and mandibuloacral dysplasia (MADA), affect the nuclear localization of barrier-to-autointegration factor (BAF), a protein able to link lamin A precursor to chromatin remodeling functions. Our findings, in accordance with previously described results, support the hypothesis of a prelamin A involvement in BAF nuclear recruitment and suggest BAF-prelamin A complex as a protein platform usually activated in prelamin A-accumulating diseases. Finally, we demonstrate the involvement of the inner nuclear membrane protein emerin in the proper localization of BAF-prelamin A complex.

  6. 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.

  7. Proposal of Readout Electronics for CSNS-WNS BaF2 Detector

    CERN Document Server

    Zhang, Deliang; Wang, Qi; He, Bing; Zhang, Yaxi; Qi, Xincheng; Yu, Tao; An, Qi

    2016-01-01

    BaF2 (Barium fluoride) detector is one of the experiment facilities at the under construction CSNS-WNS (White Neutron Source at China Spallation Neutron Source). It is designed for precisely measuring (n,gamma) cross section with total 92 crystal elements and completely 4 pi steradian coverage. In this proposal for readout electronics, waveform digitizing technique with 1GSps sampling rate and 12-bit resolution is adopted to precisely capture the detector signal. To solve the problem of massive data readout and processing, the readout electronics system is designed into a distributed architecture with 4 PXIe crates. The digitized detector's signal is concentrated to PXIe crate controller through PCIe bus on backplane and transmitted to data acquisition system over Gigabit Ethernet in parallel. Besides, clock and trigger can be fanned out synchronously to each electronic channel over a high-precision distributing network. Test results showed that the prototype of the readout electronics system achieved good pe...

  8. Structures, Branching Ratios and Laser Cooling Scheme for 138BaF Molecule

    CERN Document Server

    Chen, Tao; Yan, Bo

    2016-01-01

    For laser cooling considerations, we have theoretically investigated the electronic, rovibrational and hypefine structures of BaF molecule. The highly diagonal Franck-Condon factors and the branching ratios for all possible transitions within the lowest-lying four electronic states have also been calculated. Meanwhile, the mixing between metastable A'2{\\Delta} and A2{\\Pi} states and further the lifetime of the {\\Delta} state have been estimated since the loss procedure via {\\Delta} state would like fatally destroy the main quasi-cycling {\\Sigma}-{\\Pi} transition for cooling and trapping. The resultant hyperfine splittings of each rovibrational states in X2{\\Sigma}+ state provide benchmarksfor sideband modulations of cooling and repumping lasers and remixing microwaves to address all necessary levels. The calculated Zeeman shift and g-factors for both X and A states serve as benchmarks for selections of the trapping laser polarizations. Our study paves the way for future laser cooling and magneto-optical trapp...

  9. Phonons in mixed superionic fluorites (BaF2)1–(LaF3)

    Indian Academy of Sciences (India)

    M M Sinha

    2002-11-01

    In recent years, the fluorite-structured solid solutions with the general formula, (MF2)1–(RF3) (M = Ca, Sr, Ba, Pb and R is a rare-earth element or Y), have been the subject of numerous experimental studies focussed on their superionic properties. The overall cubic crystal symmetry (space group 3) is conserved up to ≤ max, where max 0.4–0.5 depending on M and R. The zone centre phonons and phonon dispersion along three symmetry directions of the mixed superionic compound (BaF2)1–(LaF3) have been investigated by applying de Launey angular force model for ≤ max. The calculated results are compared and explained with available experimental results.

  10. [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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. BAF53b, a Neuron-Specific Nucleosome Remodeling Factor, Is Induced after Learning and Facilitates Long-Term Memory Consolidation.

    Science.gov (United States)

    Yoo, Miran; Choi, Kwang-Yeon; Kim, Jieun; Kim, Mujun; Shim, Jaehoon; Choi, Jun-Hyeok; Cho, Hye-Yeon; Oh, Jung-Pyo; Kim, Hyung-Su; Kaang, Bong-Kiun; Han, Jin-Hee

    2017-03-29

    Although epigenetic mechanisms of gene expression regulation have recently been implicated in memory consolidation and persistence, the role of nucleosome-remodeling is largely unexplored. Recent studies show that the functional loss of BAF53b, a postmitotic neuron-specific subunit of the BAF nucleosome-remodeling complex, results in the deficit of consolidation of hippocampus-dependent memory and cocaine-associated memory in the rodent brain. However, it is unclear whether BAF53b expression is regulated during memory formation and how BAF53b regulates fear memory in the amygdala, a key brain site for fear memory encoding and storage. To address these questions, we used viral vector approaches to either decrease or increase BAF53b function specifically in the lateral amygdala of adult mice in auditory fear conditioning paradigm. Knockdown of Baf53b before training disrupted long-term memory formation with no effect on short-term memory, basal synaptic transmission, and spine structures. We observed in our qPCR analysis that BAF53b was induced in the lateral amygdala neurons at the late consolidation phase after fear conditioning. Moreover, transient BAF53b overexpression led to persistently enhanced memory formation, which was accompanied by increase in thin-type spine density. Together, our results provide the evidence that BAF53b is induced after learning, and show that such increase of BAF53b level facilitates memory consolidation likely by regulating learning-related spine structural plasticity.SIGNIFICANCE STATEMENT Recent works in the rodent brain begin to link nucleosome remodeling-dependent epigenetic mechanism to memory consolidation. Here we show that BAF53b, an epigenetic factor involved in nucleosome remodeling, is induced in the lateral amygdala neurons at the late phase of consolidation after fear conditioning. Using specific gene knockdown or overexpression approaches, we identify the critical role of BAF53b in the lateral amygdala neurons for memory

  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. 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.

  19. 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.

  20. 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.

  1. A 4p BaF2 detector for (n,g) cross section measurements at a spallation neutron source

    CERN Document Server

    Heil, M; Fowler, M M; Haight, R C; Käppeler, F; Rundberg, R S; Seabury, E H; Ullmann, J L; Wilhelmy, J B; Wisshak, K

    2013-01-01

    The quest for improved neutron capture cross sections for advanced reactor concepts, transmutation of radioactive wastes as well as for astrophysical scenarios of neutron capture nucleosynthesis has motivated new experimental efforts based on modern techniques. Recent measurements in the keV region have shown that a 4p BaF2 detector represents an accurate and versatile instrument for such studies. The present work deals with the potential of such a 4p BaF2 detector in combination with spallation neutron sources, which offer large neutron fluxes over a wide energy range. Detailed Monte Carlo simulations with the GEANT package have been performed to investigate the critical backgrounds at a spallation facility, to optimize the detector design, and to discuss alternative solutions.

  2. BAF Complex Is Closely Related to and Interacts with NF1/CTF and RNA Polymerase Ⅱ in Gene Transcriptional Activation

    Institute of Scientific and Technical Information of China (English)

    Li-Hui ZHAO; Xue-Qing BA; Xiao-Guang WANG; Xiao-Juan ZHU; Li WANG; Xian-Lu ZENG

    2005-01-01

    Brg- or hBrm-associated factor (BAF) complexes, a chromatin-remodeling complex family of mammalian cells, facilitate transcriptional activity by remodeling nucleosome structure. Brg 1 is the core subunit of Brg-associated factor complexes. In the present study, we investigated the spatial relationship between Brg1 and nuclear factor 1 (NF1/CTF) and RNA polymerase Ⅱ (RNAP Ⅱ) upon gene transcriptional activation in vivo by employing immuno-gold labeling. The data showed that Brg1 was closely co-localized with NF1/CTF and RNAP Ⅱ in HeLa cells. Moreover, the co-immunoprecipitation assay further revealed that Brg1 can be isolated together with NF1/CTF and RNAP Ⅱ in the ConA-stimulated, but not the resting,T lymphocyte. The combined results suggested that BAF complexes can interact with NF1/CTF and RNAP Ⅱ, and this interaction is closely dependent on the activation of gene transcription.

  3. The effects of Tb3+ doping concentration on luminescence properties and crystal structure of BaF2 phosphor

    Indian Academy of Sciences (India)

    Zhenxing Du; Quansheng Liu; Tianjiang Hou; Yue Song; Xiyan Zhang; Yanyu Cui

    2015-06-01

    This paper is aimed at explaining the effects of Tb3+ concentration on structure and luminescence properties and clarifying the concentration quenching mechanism of Tb3+. The lattice of BaF2 decreases with the increase of Tb3+ ions concentration. The emission spectrum of BaF2:Tb3+ consists of blue emission band and green emission band and corresponds to the transition of 5D3 $\\to$ 7F ( =0, 1, 2, 4, 5, 6) and 5D4 $\\to$ 7F ( =2, 3, 4, 5, 6) of Tb3+. The optimum concentration of Tb3+ is 4 mol%, and the concentration quenching mechanism of Tb3+ can be interpreted by the dipole–quadrupole (d–q) interaction.

  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. Investigation of rare nuclear decays with BaF$_2$ crystal scintillator contaminated by radium

    CERN Document Server

    Belli, P; Cappella, F; Caracciolo, V; Cerulli, R; Danevich, F A; Di Marco, A; Incicchitti, A; Poda, D V; Polischuk, O G; Tretyak, V I

    2014-01-01

    The radioactive contamination of a BaF$_2$ scintillation crystal with mass of 1.714 kg was measured over 101 hours in the low-background DAMA/R&D set-up deep underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN (LNGS, Italy). The half-life of $^{212}$Po (present in the crystal scintillator due to contamination by radium) was measured as $T_{1/2}(^{212}$Po) = 298.8$\\pm$0.8(stat.)$\\pm$1.4(syst.) ns by analysis of the events' pulse profiles. The $^{222}$Rn nuclide is known as 100% decaying via emission of $\\alpha$ particle with $T_{1/2}$ = 3.82 d; however, its $\\beta$ decay is also energetically allowed with $Q_\\beta = 24\\pm21$ keV. Search for decay chains of events with specific pulse shapes characteristic for $\\alpha$ or for $\\beta/\\gamma$ signals and with known energies and time differences allowed us to set, for the first time, the limit on the branching ratio of $^{222}$Rn relatively to $\\beta$ decay as $B_\\beta 8.0$ y). Half-life limits of $^{212}$Pb, $^{222}$Rn and $^{226}$Ra rel...

  8. Numerical modeling of radiative heat transfer in Bridgman solidification of semi-transparent BaF 2 crystals

    Science.gov (United States)

    Stelian, C.

    2007-08-01

    The radiative heat transfer during Bridgman solidification of semi-transparent barium fluoride (BaF 2) crystals is numerically investigated by using the commercial software FIDAP. This code uses the P-1 approximation for the participating media modeling. The thermal field and the solid-liquid interface shape are computed for an opaque melt-crystal sample, a semi-transparent grey sample and a semi-transparent non-grey sample. The transient numerical analysis of the latent heat influence on the interface deflection shows a significant effect on the interface shape. In the case of an opaque sample, this effect is huge because of the small thermal conductivity of the BaF 2 melt. The interface curvature is drastically reduced when the latent heat is taken into account, and the growth front, which has a convex shape, becomes flat when the growth rate increases. The latent heat effect is reduced in the case of the participating BaF 2 sample because the effective thermal conductivity of the melt is augmented by the internal radiative heat transfer. The internal radiative effect is small at low solidified fractions but becomes significant when the crystal length increases, leading to a more curved interface. When the growth rates are greater than a critical value, the interface becomes concave and a destabilization of the growth process can occur. These results are in agreement with previous experimental measurements of the interface curvature and analytical investigations of the factors affecting the interface deflection.

  9. The BAF complex interacts with Pax6 in adult neural progenitors to establish a neurogenic cross-regulatory transcriptional network.

    Science.gov (United States)

    Ninkovic, Jovica; Steiner-Mezzadri, Andrea; Jawerka, Melanie; Akinci, Umut; Masserdotti, Giacomo; Petricca, Stefania; Fischer, Judith; von Holst, Alexander; Beckers, Johanes; Lie, Chichung D; Petrik, David; Miller, Erik; Tang, Jiong; Wu, Jiang; Lefebvre, Veronique; Demmers, Jeroen; Eisch, Amelia; Metzger, Daniel; Crabtree, Gerald; Irmler, Martin; Poot, Raymond; Götz, Magdalena

    2013-10-03

    Numerous transcriptional regulators of neurogenesis have been identified in the developing and adult brain, but how neurogenic fate is programmed at the epigenetic level remains poorly defined. Here, we report that the transcription factor Pax6 directly interacts with the Brg1-containing BAF complex in adult neural progenitors. Deletion of either Brg1 or Pax6 in the subependymal zone (SEZ) causes the progeny of adult neural stem cells to convert to the ependymal lineage within the SEZ while migrating neuroblasts convert to different glial lineages en route to or in the olfactory bulb (OB). Genome-wide analyses reveal that the majority of genes downregulated in the Brg1 null SEZ and OB contain Pax6 binding sites and are also downregulated in Pax6 null SEZ and OB. Downstream of the Pax6-BAF complex, we find that Sox11, Nfib, and Pou3f4 form a transcriptional cross-regulatory network that drives neurogenesis and can convert postnatal glia into neurons. Taken together, elements of our work identify a tripartite effector network activated by Pax6-BAF that programs neuronal fate.

  10. 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.

  11. 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)

  12. 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

  13. 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.

  14. 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.

  15. 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...

  16. 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.

  17. BAF250B-associated SWI/SNF chromatin-remodeling complex is required to maintain undifferentiated mouse embryonic stem cells

    Science.gov (United States)

    Yan, Zhijiang; Wang, Zhong; Sharova, Lioudmila; Sharov, Alexei A.; Ling, Chen; Piao, Yulan; Aiba, Kazuhiro; Matoba, Ryo; Wang, Weidong; Ko, Minoru S.H.

    2008-01-01

    Whether SWI/SNF chromatin remodeling complexes play roles in embryonic stem (ES) cells remains unknown. Here we show that SWI/SNF complexes are present in mouse ES cells, and their composition is dynamically regulated upon induction of ES cell differentiation. For example, the SWI/SNF purified from undifferentiated ES cells contains a high level of BAF155 and a low level of BAF170 (both of which are homologs of yeast SWI3 protein), whereas that from differentiated cells contains near equal amounts of both. Moreover, the levels of BAF250A and BAF250B decrease, whereas that of BRM increases, during the differentiation of ES cells. The altered expression of SWI/SNF components hinted that these complexes could play roles in ES cell maintenance or differentiation. We therefore generated ES cells with biallelic inactivation of BAF250B, and found that these cells display a reduced proliferation rate and an abnormal cell cycle. Importantly, these cells are deficient in self-renewal capacity of undifferentiated ES cells, and exhibit certain phenotypes of differentiated cells, including reduced expression of several pluripotency-related genes, and increased expression of some differentiation-related genes. These data suggest that the BAF250B-associated SWI/SNF is essential for mouse ES cells to maintain its normal proliferation and pluripotency. The work presented here underscores the importance of SWI/SNF chromatin remodeling complexes in pluripotent stem cells. PMID:18323406

  18. SWI/SNF Protein Component BAF250a Regulates Cardiac Progenitor Cell Differentiation by Modulating Chromatin Accessibility during Second Heart Field Development*

    Science.gov (United States)

    Lei, Ienglam; Gao, Xiaolin; Sham, Mai Har; Wang, Zhong

    2012-01-01

    ATP-dependent SWI/SNF chromatin remodeling complexes alter the structure of chromatin at specific loci and facilitate tissue-specific gene regulation during development. Several SWI/SNF subunits are required for cardiogenesis. However, the function and mechanisms of SWI/SNF in mediating cardiac progenitor cell (CPC) differentiation during cardiogenesis are not well understood. Our studies of the SWI/SNF chromatin remodeling complex identified that BAF250a, a regulatory subunit of the SWI/SNF, plays a key role in CPC differentiation. BAF250a ablation in mouse second heart field (SHF) led to trabeculation defects in the right ventricle, ventricular septal defect, persistent truncus arteriosus, reduced myocardial proliferation, and embryonic lethality around E13. Using an embryonic stem cell culture system that models the formation and differentiation of SHF CPCs in vivo, we have shown that BAF250a ablation in CPCs specifically inhibits cardiomyocyte formation. Moreover, BAF250a selectively regulates the expression of key cardiac factors Mef2c, Nkx2.5, and Bmp10 in SHF CPCs. Chromatin immunoprecipitation and DNase I digestion assays indicate that BAF250a regulates gene expression by binding selectively to its target gene promoters and recruiting Brg1, the catalytic subunit of SWI/SNF, to modulate chromatin accessibility. Our results thus identify BAF250a-mediated chromatin remodeling as an essential epigenetic mechanism mediating CPC differentiation. PMID:22621927

  19. SWI/SNF protein component BAF250a regulates cardiac progenitor cell differentiation by modulating chromatin accessibility during second heart field development.

    Science.gov (United States)

    Lei, Ienglam; Gao, Xiaolin; Sham, Mai Har; Wang, Zhong

    2012-07-13

    ATP-dependent SWI/SNF chromatin remodeling complexes alter the structure of chromatin at specific loci and facilitate tissue-specific gene regulation during development. Several SWI/SNF subunits are required for cardiogenesis. However, the function and mechanisms of SWI/SNF in mediating cardiac progenitor cell (CPC) differentiation during cardiogenesis are not well understood. Our studies of the SWI/SNF chromatin remodeling complex identified that BAF250a, a regulatory subunit of the SWI/SNF, plays a key role in CPC differentiation. BAF250a ablation in mouse second heart field (SHF) led to trabeculation defects in the right ventricle, ventricular septal defect, persistent truncus arteriosus, reduced myocardial proliferation, and embryonic lethality around E13. Using an embryonic stem cell culture system that models the formation and differentiation of SHF CPCs in vivo, we have shown that BAF250a ablation in CPCs specifically inhibits cardiomyocyte formation. Moreover, BAF250a selectively regulates the expression of key cardiac factors Mef2c, Nkx2.5, and Bmp10 in SHF CPCs. Chromatin immunoprecipitation and DNase I digestion assays indicate that BAF250a regulates gene expression by binding selectively to its target gene promoters and recruiting Brg1, the catalytic subunit of SWI/SNF, to modulate chromatin accessibility. Our results thus identify BAF250a-mediated chromatin remodeling as an essential epigenetic mechanism mediating CPC differentiation.

  20. 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

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Scintillation light simulation in big-sized BaF$_{2}$ and pure CsI crystals

    CERN Document Server

    Usubov, Zafar

    2016-01-01

    We have investigated scintillation light distribution in BaF$_{2}$ and pure CsI crystals with dimensions 3x3x20 cm$^{3}$ using the Geant4 toolkit. The diffuse wrapping material is selected as coating for the crystals. The simulated cosmic muons and 105 MeV electrons are used as beam particles. The optical attenuation along the crystals is explored with the simulation data. We have demonstrated the impact of the crystal surface finish on the light distribution at the crystal end, optical photon arrival time, incidence angle distributions, and optical attenuation for the studied crystals.

  14. Response of BaF 2 detectors to photons of 3-50 MeV energy

    Science.gov (United States)

    Matulewicz, T.; Grosse, E.; Emling, H.; Freifelder, R.; Grein, H.; Henning, W.; Herrmann, N.; Holzmann, R.; Kulessa, R.; Simon, R. S.; Wollersheim, H. J.; Schoch, B.; Vogt, J.; Wilhelm, M.; Kratz, J. V.; Schmidt, R.; Janssens, R. V. F.

    1990-04-01

    BaF 2 detectors of 20 cm length (10 radiation lengths) and hexagonal cross section (diameter 5.2 cm) were tested using monochromatic photons from the tagged-photon facility at the electron accelerator MAMIA at Mainz. The experimental spectra the deposited energy for a single detector and for an array of seven modules compare very well with the predictions of Monte Carlo shower simulations using the code GEANT3. At high photon energies a significant improvement (more than a factor 2) of the energy resolution is observed for the summed energy spectra as compared to the resolution of one single module.

  15. Defect-induced wetting on BaF 2(111) and CaF 2(111) at ambient conditions

    Science.gov (United States)

    Cardellach, M.; Verdaguer, A.; Fraxedas, J.

    2011-12-01

    The interaction of water with freshly cleaved (111) surfaces of isostructural BaF2 and CaF2 single crystals at ambient conditions (room temperature and under controlled humidity) has been studied using scanning force microscopy in different operation modes and optical microscopy. Such surfaces exhibit contrasting behaviors for both materials: while on BaF2(111) two-dimensional water layers are formed after accumulation at step edges, CaF2(111) does not promote the formation of such layers. We attribute such opposed behavior to lattice match (mismatch) between hexagonal water ice and the hexagonal (111) surfaces of BaF2(CaF2). Optical microscope images reveal that this behavior also determines the way the surfaces become wetted at a macroscopic level.

  16. Enhanced 2.0 microm emission and gain coefficient of transparent glass ceramic containing BaF2: Ho3+,Tm3+ nanocrystals.

    Science.gov (United States)

    Zhang, W J; Zhang, Q Y; Chen, Q J; Qian, Q; Yang, Z M; Qiu, J R; Huang, P; Wang, Y S

    2009-11-09

    Transparent glass ceramic containing BaF(2):Ho(3+),Tm(3+) nanocrystals has been prepared by melt quenching and subsequent thermal treatment. The precipitation of BaF(2) nanocrystals was confirmed by X-ray diffraction and high-resolution transmission electron microscopy. Intense 2.0 microm fluorescence originating from Ho(3+): (5)I(7) --> (5)I(8) transition was achieved upon excitation with 808 nm laser diode. A large ratio of forward Tm(3+) --> Ho(3+) energy transfer constant to that of backward process indicated high efficient energy transfer from Tm(3+)((3)F(4)) to Ho(3+)((5)I(7)), benefited from the reduced ionic distances of Tm(3+)-Tm(3+) and Tm(3+)-Ho(3+) pairs and low phonon energy environment with the incorporation of rare-earth ions into the precipitated BaF(2) nanocrystals. The results indicate that glass ceramic is a promising candidate material for 2.0 microm laser.

  17. 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.

  18. 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.

  19. 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.

  20. HIC1 interacts with a specific subunit of SWI/SNF complexes, ARID1A/BAF250A

    Energy Technology Data Exchange (ETDEWEB)

    Van Rechem, Capucine; Boulay, Gaylor [CNRS UMR 8161, Institut de Biologie de LILLE, Universite de Lille Nord de FRANCE, Institut PASTEUR de LILLE, IFR 142, 1 Rue Calmette, 59017 LILLE Cedex (France); Leprince, Dominique, E-mail: dominique.leprince@ibl.fr [CNRS UMR 8161, Institut de Biologie de LILLE, Universite de Lille Nord de FRANCE, Institut PASTEUR de LILLE, IFR 142, 1 Rue Calmette, 59017 LILLE Cedex (France)

    2009-08-07

    HIC1, a tumor suppressor gene epigenetically silenced in many human cancers encodes a transcriptional repressor involved in regulatory loops modulating p53-dependent and E2F1-dependent cell survival and stress responses. HIC1 is also implicated in growth control since it recruits BRG1, one of the two alternative ATPases (BRM or BRG1) of SWI/SNF chromatin-remodeling complexes to repress transcription of E2F1 in quiescent fibroblasts. Here, through yeast two-hybrid screening, we identify ARID1A/BAF250A, as a new HIC1 partner. ARID1A/BAF250A is one of the two mutually exclusive ARID1-containing subunits of SWI/SNF complexes which define subsets of complexes endowed with anti-proliferative properties. Co-immunoprecipitation assays in WI38 fibroblasts and in BRG1-/- SW13 cells showed that endogenous HIC1 and ARID1A proteins interact in a BRG1-dependent manner. Furthermore, we demonstrate that HIC1 does not interact with BRM. Finally, sequential chromatin immunoprecipitation (ChIP-reChIP) experiments demonstrated that HIC1 represses E2F1 through the recruitment of anti-proliferative SWI/SNF complexes containing ARID1A.

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. [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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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...

  14. 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

  15. 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.

  16. 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...

  17. 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.

  18. 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...

  19. 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)...

  20. 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...

  1. 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.

  2. 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.

  3. Spectroscopic properties of Pr3+ and Er3+ ions in lead-free borate glasses modified by BaF2

    Science.gov (United States)

    Pisarska, Joanna; Pisarski, Wojciech A.; Dorosz, Dominik; Dorosz, Jan

    2015-09-01

    Lead-free oxyfluoride borate glasses singly doped with Pr3+ and Er3+ were prepared and next investigated using absorption and luminescence spectroscopy. In the studied glass system, barium oxide was substituted by BaF2. Two luminescence bands of Pr3+ located at visible spectral region are observed, which correspond to 3P0-3H4 (blue) and 1D2-3H4 (reddish orange) transitions, respectively. The luminescence bands due to 1D2-3H4 transition of Pr3+ are shifted to shorter wavelengths, when BaO was substituted by BaF2. Near-infrared luminescence spectra of Er3+ ions in lead-free borate glasses modified by BaF2 correspond to 4I13/2-4I15/2 transition. Their spectral linewidths increase with increasing BaF2 concentration. The changes in measured lifetimes of rare earth ions are well correlated with the bonding parameters calculated from the optical absorption spectra.

  4. 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.

  5. Test of the statistical model in Mo96 with the BaF2γ calorimeter DANCE array

    Science.gov (United States)

    Sheets, S. A.; Agvaanluvsan, U.; Becker, J. A.; Bečvář, F.; Bredeweg, T. A.; Haight, R. C.; Jandel, M.; Krtička, M.; Mitchell, G. E.; O'Donnell, J. M.; Parker, W.; Reifarth, R.; Rundberg, R. S.; Sharapov, E. I.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Wu, C. Y.

    2009-02-01

    The γ-ray cascades following the Mo95(n,γ)Mo96 reaction were studied with the γ calorimeter DANCE (Detector for Advanced Neutron Capture Experiments) consisting of 160 BaF2 scintillation detectors at the Los Alamos Neutron Science Center. The γ-ray energy spectra for different multiplicities were measured for s- and p-wave resonances below 2 keV. The shapes of these spectra were found to be in very good agreement with simulations using the DICEBOX statistical model code. The relevant model parameters used for the level density and photon strength functions were identical with those that provided the best fit of the data from a recent measurement of the thermal Mo95(n,γ)Mo96 reaction with the two-step-cascade method. The reported results strongly suggest that the extreme statistical model works very well in the mass region near A=100.

  6. A Unique TAS Setup for high multiplicity events at VECC, Kolkata using BaF2 detectors

    Directory of Open Access Journals (Sweden)

    Mukherjee G.

    2014-03-01

    Full Text Available A granular total absorption spectrometer (TAS has been developed at the Variable Energy Cyclotron Centre, Kolkata, India using 50 elements of BaF2 detectors and covering 4π. The advantage with such a granular setup is that one can get sum spectrum with the condition of different multiplicity hits in an event. It has been shown that one can get clean sum-peaks devoid of individual peaks with the choice of two or higher fold of multiplicity. The large granularity makes it a unique TAS setup particularly for the high multiplicity events. The set up has been tested using different radioactive sources with one, two or multiple γ rays in cascade. The set up is ready to be used online.

  7. 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.

  8. 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.

  9. 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.

  10. [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.

  11. 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.

  12. 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)

  13. 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).

  14. 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...

  15. 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....

  16. 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.

  17. [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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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...

  14. 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%.

  15. 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.

  16. 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.

  17. Ultralow threshold green lasing and optical bistability in ZBNA (ZrF4-BaF2-NaF-AlF3) microspheres

    Science.gov (United States)

    Wu, Yuqiang; Ward, Jonathan M.; Nic Chormaic, Síle

    2010-02-01

    Upconversion lasing and fluorescence from active microspheres fabricated from a novel fluorozirconate, Er3+ doped glass, ZBNA (ZrF4-BaF2-NaF-AlF3), when pumped at 978 nm via a tapered optical fiber is demonstrated. An ultralow, green lasing threshold of ˜3 μW for 550 nm emissions is measured. This is one order of magnitude lower than that previously reported for ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) microspheres. Optical bistability effects in ZBNA microspheres are reported and the bistable mechanism is discussed and attributed to shifts of the whispering gallery modes due to thermal expansion of the sphere, where heating is achieved by optical pumping around 978 nm. The effect of the bistability on the upconversion lasing is examined and we report multiple bistability loops within the microspheres.

  18. Ho3+/Yb3+ co-doped TeO2-BaF2-Y2O3 glasses for ∼1.2 μm laser applications

    Science.gov (United States)

    Wang, Shunbin; Li, Chengzhi; Yao, Chuanfei; Jia, Shijie; Jia, Zhixu; Qin, Guanshi; Qin, Weiping

    2017-02-01

    Intense ∼1.2 μm fluorescence is observed in Ho3+/Yb3+ co-doped TeO2-BaF2-Y2O3 glasses under 915 nm laser diode excitation. The 1.2 μm emission can be ascribed to the transition 5I6→5I8 of Ho3+. With the introducing of BaF2, the content of OH in the glasses drops markedly, and the 1.2 μm emission intensity increases gradually as increasing the concentration percentage of BaF2. Furthermore, microstructured fibers based on the TeO2-BaF2-Y2O3 glasses are fabricated by using a rod-in-tube method, and a relative positive gain of ∼9.42 dB at 1175.3 nm is obtained in a 5 cm long fiber.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Luminescence properties of dual valence Eu doped nano-crystalline BaF2 embedded glass-ceramics and observation of Eu2+ → Eu3+ energy transfer.

    Science.gov (United States)

    Biswas, Kaushik; Sontakke, Atul D; Sen, R; Annapurna, K

    2012-03-01

    Europium doped glass-ceramics containing BaF(2) nano-crystals have been prepared by using the controlled crystallization of melt-quenched glasses. X-ray diffraction and transmission electron microscopy have confirmed the presence of cubic BaF(2) nano-crystalline phase in glass matrix in the ceramized samples. Incorporation of rare earth ions into the formed crystalline phase having low phonon energy of 346 cm(-1) has been demonstrated from the emission spectra of Eu(3+) ions showing the transitions from upper excitation states (5)D(J) (J = 1, 2, and 3) to ground states for the glass-ceramics samples. The presence of divalent europium ions in glass and glass-ceramics samples is confirmed from the dominant blue emission corresponding to its 5d-4f transition under an excitation of 300 nm. Increase in the reduction of trivalent europium (Eu(3+)) ions to divalent (Eu(2+)) with the extent of ceramization is explained by charge compensation model based on substitution defect mechanisms. Further, the phenomenon of energy transfer from Eu(2+) to Eu(3+) ion by radiative trapping or re-absorption is evidenced which increases with the degree of ceramization. For the first time, the reduction of Eu(3+) to Eu(2+) under normal air atmospheric condition has been observed in a BaF(2) containing oxyfluoride glass-ceramics system.

  11. Spectroscopic properties and mechanism of Tm3+/Er3+/Yb3+co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals

    Science.gov (United States)

    Hu, Yue-Bo; Qiu, Jian-Bei; Zhou, Da-Cheng; Song, Zhi-Guo; Yang, Zheng-Wen; Wang, Rong-Fei; Jiao, Qing; Zhou, Da-Li

    2014-02-01

    Transparent Tm3+/Er3+/Yb3+ co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals are prepared. Under excitation of a 980-nm laser diode (LD), compared with the glass before heat treatment, the Tm3+/Er3+/Yb3+co-doped oxyfluorogermanate glass ceramics can emit intense blue, green and red up-conversion luminescence and Stark-split peaks; X-ray diffraction (XRD) and transmission electron microscope (TEM) results show that BaF2 nanocrystals with an average diameter of 20 nm are precipitated from the glass matrix. Stark splitting of the up-conversion luminescence peaks in the glass ceramics indicates that Tm3+, Er3+ and (or) Yb3+ ions are incorporated into the BaF2 nanocrystals. The up-conversion luminescence intensities of Tm3+, Er3+ and the splitting degree of luminescence peaks in the glass ceramics increase significantly with the increase of heat treat temperature and heat treat time extension. In addition, the possible energy transfer process between rare earth ions and the up-conversion luminescence mechanism are also proposed.

  12. Optical characterization of Tm3+ doped Bi2O3-GeO2-Ga2O3 glasses in absence and presence of BaF2

    Science.gov (United States)

    Han, Kexuan; Zhang, Peng; Wang, Shunbin; Guo, Yanyan; Zhou, Dechun; Yu, Fengxia

    2016-08-01

    In this paper, Two new Bi2O3-GeO2-Ga2O3 glasses (one presence of BaF2) doped with 1mol% Tm2O3 were prepared by melt-quenching technique. Differential thermal analysis (DTA), the absorption, Raman, IR spectra and fluorescence spectra were measured. The Judd-Ofelt intensity parameters, emission cross section, absorption cross section, and gain coefficient of Tm3+ ions were comparatively investigated. After the BaF2 introduced, the glass showed a better thermal stability, lower phonon energy and weaker OH- absorption coefficient, meanwhile, a larger ~1.8 μm emission cross section σem (7.56 × 10-21 cm2) and a longer fluorescence lifetime τmea (2.25 ms) corresponding to the Tm3+: 4F3 → 3H6 transition were obtained, which is due to the addition of fluoride in glass could reduce the quenching rate of hydroxyls and raise the cross-relaxation (3H6 + 3H4 → 3F4 + 3F4) rate. Our results suggest that the Tm3+ doped Bi2O3-GeO2-Ga2O3 glass with BaF2 might be potential to the application in efficient ~1.8 μm lasers system.

  13. CCR7 is involved in BCR-ABL/STAP-2-mediated cell growth in hematopoietic Ba/F3 cells.

    Science.gov (United States)

    Kubo, Kaori; Iwakami, Masashi; Muromoto, Ryuta; Inagaki, Takuya; Kitai, Yuichi; Kon, Shigeyuki; Sekine, Yuichi; Oritani, Kenji; Matsuda, Tadashi

    2015-08-07

    Chronic myeloid leukemia is a clonal disease characterized by the presence of the Philadelphia chromosome and its oncogenic product, BCR-ABL, which activates multiple pathways involved in cell survival, growth promotion, and disease progression. We previously reported that in murine hematopoietic Ba/F3 cells, signal transducing adaptor protein-2 (STAP-2) binds to BCR-ABL and up-regulates BCR-ABL phosphorylation, leading to enhanced activation of its downstream signaling molecules. The binding of STAP-2 to BCR-ABL also influenced the expression levels of chemokine receptors, such as CXCR4 and CCR7. For the induction of CCR7 expression, signals mediated by the MAPK/ERK pathway were critical in Ba/F3 cells expressing BCR-ABL and STAP-2. In addition, STAP-2 cooperated with BCR-ABL to induce the production of CCR7 ligands, CCL19 and CCL21. Our results demonstrate a contribution of CCR7 to STAP-2-dependent enhancement of BCR-ABL-mediated cell growth in Ba/F3 cells.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Molecular-beam optical Stark and Zeeman study of the A {sup 2}{Pi}--X {sup 2}{Sigma}{sup +} (0,0) band system of BaF

    Energy Technology Data Exchange (ETDEWEB)

    Steimle, Timothy C.; Frey, Sarah; Le, Anh; DeMille, David; Rahmlow, David A.; Linton, Colan [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604 (United States); Department of Physics, Yale University, P.O. Box 208120, New Haven, Connecticut 06520 (United States); Centre for Laser Atomic and Molecular Sciences, Physics Department, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick, E3B 5A3 (Canada)

    2011-07-15

    The A {sup 2}{Pi}-X {sup 2}{Sigma}{sup +} (0,0) band system of barium monofluoride (BaF) has been recorded using high-resolution laser-induced fluorescence spectroscopy both field-free and in the presence of static magnetic and electric fields. The field-free spectra for the {sup 135}BaF, {sup 137}BaF, and {sup 138}BaF isotopologues were modeled to generate an improved set of spectroscopic constants for the A {sup 2}{Pi}({upsilon} = 0) and X {sup 2}{Sigma}{sup +}({upsilon} = 0) states. The observed optical Stark shifts for the {sup 138}BaF isotopologue were analyzed to produce the permanent electric dipole moments of 1.50(2) and 1.31(2) D for the A {sup 2}{Pi}{sub 1/2}({upsilon} = 0) and A {sup 2}{Pi}{sub 3/2} ({upsilon} = 0) states, respectively. The observed optical Zeeman shifts for the {sup 138}BaF isotopologue were analyzed to produce a set of magnetic g factors for the A {sup 2}{Pi}({upsilon} = 0) and X {sup 2}{Sigma}{sup +}({upsilon} = 0) states.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. Simultaneous measurement of (n, γ) and (n, fission) cross sections with the DANCE 4π BaF 2 array

    Science.gov (United States)

    Bredeweg, T. A.; Fowler, M. M.; Becker, J. A.; Bond, E. M.; Chadwick, M. B.; Clement, R. R. C.; Esch, E.-I.; Ethvignot, T.; Granier, T.; Jandel, M.; Macri, R. A.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Wu, C. Y.

    2007-08-01

    We have recently begun a program of high precision measurements of the key production and destruction reactions of important radiochemical diagnostic isotopes, including several isotopes of uranium, plutonium and americium. The detector for advanced neutron capture experiments (DANCE), a 4π BaF2 array located at the Los Alamos Neutron Science Center, will be used to measure the neutron capture cross sections for most of the isotopes of interest. However, neutron capture measurements on many of the actinides are complicated by the presence of prompt γ-rays arising from low energy neutron-induced fission, which competes with neutron capture to varying degrees. Previous measurements of 235U using the DANCE array have shown that we can partially resolve capture from fission events based on total γ-ray calorimetry (i.e. total γ-ray energy versus γ-ray multiplicity). The addition of a dedicated fission-tagging detector to the DANCE array has greatly improved our ability to separate these two competing processes. In addition to higher quality neutron capture data, the addition of a fission-tagging detector offers a means to determine the capture-to-fission ratio (σγ/σf) in a single measurement, which should reduce the effect of systematic uncertainties. We are currently using a dual parallel-plate avalanche counter (PPAC) with the target material electro-deposited directly on the center cathode foil. This design provides a high efficiency for detecting fission fragments and allows loading of pre-assembled target/detector assemblies into the neutron beam line at DANCE. Results from tests of the fission-tag detector, as well as preliminary results from measurements on 235U and 252Cf that utilized the fission-tag detector will be presented.

  14. 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. ...

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. 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.

  20. 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).

  1. 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.

  2. 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.

  3. [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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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..

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. Alpha-gamma pulse shape discrimination in CsI:Tl, CsI:Na and BaF sub 2 scintillators

    CERN Document Server

    Dinca, L E; Haas, J; Bom, V R; Eijk, C W E

    2002-01-01

    Some scintillating materials offer the possibility of measuring well separated alpha and gamma scintillation response using a single crystal. Eventually aiming at thermal neutron detection using sup 6 Li or sup 1 sup 0 B admixture, pulse shape discrimination measurements were made on three scintillators: CsI:Tl, CsI:Na and pure BaF sub 2 crystals. A very good alpha/gamma discrimination was obtained using sup 2 sup 2 Na, sup 2 sup 4 sup 1 Am (gamma) and sup 2 sup 4 sup 4 Cm (alpha) radioactive sources.

  19. Role of magnetism in superconductivity of BaF e2A s2 : Study of 5 d Au-doped crystals

    Science.gov (United States)

    Li, Li; Cao, Huibo; McGuire, Michael A.; Kim, Jungsoo S.; Stewart, Greg R.; Sefat, Athena S.

    2015-09-01

    We investigate properties of BaF e2A s2 (122) single crystals upon gold doping, which is the transition metal with the highest atomic weight. The Au substitution into the FeAs-planes of 122 crystal structure (Au-122) is only possible up to a small amount of ˜3 % . We find that 5 d is more effective in reducing magnetism in 122 than its counter 3 d Cu, and this relates to superconductivity. We provide evidence of short-range magnetic fluctuations and local lattice inhomogeneities that may prevent strong percolative superconductivity in Ba (Fe1-xA ux) 2A s2 .

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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....

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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,

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Air Flotation/Hydrolysis Acidification/Biological Contact Oxidation/BAF Process for Soft Drink-processing Wastewater Treatment%气浮/水解酸化/接触氧化/BAF工艺处理饮料生产废水

    Institute of Scientific and Technical Information of China (English)

    潘登; 王娟; 周俊强; 贾莹莹

    2013-01-01

    The wastewater from a soft drink-processing enterprise was characterized with high concentration of SS and good biodegradability. Air flotation/hydrolysis acidification/biological contact oxidation/biological aerated filter process was used to treat the wastewater. High treatment efficiency was a-chieved, and the effluent quality met the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant ( GB 18918 - 2002 ) .%某饮料生产企业废水具有悬浮物含量较高、可生化性较好的特点,采用气浮/水解酸化/生物接触氧化/曝气生物滤池多级工艺处理,取得了较好的处理效果,出水水质达到了《城镇污水处理厂污染物排放标准》(GB 18918-2002)的一级A标准.

  18. 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

  19. Spectroscopy of laser properties of Nd(3+)-doped CaF2, SrF2, and BaF2

    Science.gov (United States)

    Payne, Stephen A.; Caird, John A.; Chase, L. L.; Smith, L. K.; Nielsen, N. D.; Krupke, William F.

    1990-03-01

    The optical properties of Nd(3+) in CaF2, SrF2, and BaF2 were investigated in order to determine if these materials are useful as laser-pumped amplifier media. The CaF2:Nd crystal was found to not be useful because the impurities tend to cluster at very low concentration, leading to the formation of nonluminescent centers. On the other hand, the Nd(3+) centers in BaF2 exhibit unacceptably low transition strengths. SrF2:Nd appears to have adequate absorption strength, and, in addition, to have a remarkably long emission lifetime of 1280 microns. A maximum doping of 0.20 atomic percent Nd(3+) can be tolerated in SrF2 without the occurrence of detrimental clustering. The peak emission cross section of SrF2:Nd is 1.7 x 10(exp -20) sq cm at 1036.5 nm. Direct measurement of the gain spectrum of SrF2:Nd(3+) reveals the presence of the F-4(sub 3/2) yields G-2(sub 9/2) excited state absorption lines, although the impact on the emission cross section is minor.

  20. 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

  1. 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.

  2. Relationship of BAF Complex and Transcription Factor NF1/CTF with RNA Polymerase Ⅱ%BAF复合物和转录因子NF1/CTF与RNA聚合酶Ⅱ的联系

    Institute of Scientific and Technical Information of China (English)

    姜革强; 邓国忠; 王霞

    2006-01-01

    通过ELISA实验观察小鼠脾T淋巴细胞和Jurkat细胞经ConA处理后,BAF(hSWI/SNF)复合物、转录因子NF1/CTF、RNA聚合酶Ⅱ蛋白表达量的变化情况.实验证实,细胞活化后,复合物BAF(hSWI/SNF)、转录因子NF1/CTF、RNA聚合酶Ⅱ的表达发生了变化,表明它们和细胞的转录活动有关.

  3. 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

  4. 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...

  5. 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), ...

  6. [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.

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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...

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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....

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. [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)).

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Cumulants and waitingtime distribution of the photon emission from driven BaF molecule%外场作用下BaF分子发射光子累积量及等待时间分布的研究∗

    Institute of Scientific and Technical Information of China (English)

    古丽姗; 彭勇刚

    2016-01-01

    In this paper, we consider a single BaF molecule driven by an external field. When the symmetry is broken, the states of the BaF molecule demonstrate the permanent dipole moments. An external laser field to excite BaF molecule transition from its ground state to its excited state, and a radio frequency field couple with the permanent dipole moment of the BaF. The first order and second order cumulants of the emission photons and the waiting time distribution are studied via the recently developed generating function approach, which is very convenient to study the counting statistics and the corresponding probability distributions. The results demonstrate that the radio frequency field could help the BaF molecule to absorb photons from the driving field. The second and third order waiting time distributions oscillate with the evolution time, which reflects the states oscillating with the external radio frequency field.

  13. 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.

  14. 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.

  15. 内循环BAF技术处理碱渣工程应用%Engineering application of internal circulating BAF technology to the pretreatment of alkaline residue

    Institute of Scientific and Technical Information of China (English)

    李明达; 王建

    2016-01-01

    中石油兰州石化公司碱渣装置采用内循环BAF生物处理技术预处理碱渣。整套系统能够满足兰州石化厂现有碱渣处理量的需求,解决了该厂碱渣处理难题。对内循环BAF反冲洗沉淀池进行及时清淤,能够改善反冲洗给水水质、提升反冲洗系统的效率,进而有助于提高内循环BAF的出水效果。在出水水质满足设计要求的前提下,当前9组(共12组)内循环BAF池运转对碱渣的处理量可达到8.3 m3/h,核算运行成本为38元/t。%Internal circulating BAF biological oxidation technology has been used in the alkaline residue equipment in PetroChina Lanzhou Petrochemical Co. for the pretreatment of alkaline residue. The whole system is capable for meeting the requirement for the present alkaline residue treatment capacity in Lanzhou Petrochemical Plant. Thus , the problems in alkaline residue treatment in that plant has now been solved. The discharge of sludge from the flush-ing sedimentation tank in time is very helpful for improving the quality of backwashing water supply ,upgrading the efficiency of the backwashing system,and,furthermore,upgrading the effluent effect of internal circulating BAF. On the premise that the effluent water quality meets the designed requirements ,the alkaline residue treatment capacity by the operation of the first 9 groups (12 groups altogether) of internal circulating BAF tank can reach 8.3 m3/h, whose accounting cost is CNY38 per ton.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 10BaF2∶NaF, Na3AlF6/TiO2 composite as a novel visible-light-driven photocatalyst based on upconversion emission

    Institute of Scientific and Technical Information of China (English)

    Liu En-Zhou; Fan Jun; Hu Xiao-Yun; Hou Wen-Qian; Dai Hong-Zhe

    2012-01-01

    A rare-earth free upconversion luminescent material,10BaF2∶NaF,Na3AlF6,is synthesized by a hydrothermal method.The study of fluorescent spectrum indicates that it can convert visible light (550 nm-610 nm) into ultraviolet light (290 nm-350 nm),and two emission peaks at 304 nm and 324 nm are observed under the excitation of 583 nm at room temperature.Subsequently,10BaF2∶NaF,Na3AlF6/TiO2 composite photocatalyst is prepared and its catalyticactivity is evaluated by the photocatalytic reduction of CO2 under visible light irradiation (λ > 515 nm).The resultsshow that 10BaF2∶NaF,Na3AlF6/TiO2 is a more effective photocatalyst for CO2 reduction than pure TiO2,their corresponding methanol yields are 179 and 0 μmol/g-cat under the same conditions.Additionally,the mechanism of photocatalytic reduction of CO2 on 10BaF2∶NaF,Na3A1F6/TiO2 is proposed.

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Doping-dependent critical current properties in K, Co, and P-doped BaF e2A s2 single crystals

    Science.gov (United States)

    Ishida, Shigeyuki; Song, Dongjoon; Ogino, Hiraku; Iyo, Akira; Eisaki, Hiroshi; Nakajima, Masamichi; Shimoyama, Jun-ichi; Eisterer, Michael

    2017-01-01

    In order to establish the doping dependence of the critical current properties in the iron-based superconductors, the in-plane critical current density Jc of BaF e2A s2 -based superconductors B a1 -xKxF e2A s2 (K-Ba122), Ba (F e1 -xC ox)2A s2 (Co-Ba122), and BaF e2(As1-xPx) 2 (P-Ba122) in a wide range of doping concentration x was investigated by means of magnetization hysteresis loop (MHL) measurements on single-crystal samples. Depending on the dopant elements and their concentration, Jc exhibits a variety of magnetic-field H and temperature T dependences. (1) In the case of K-Ba122, the MHL of the underdoped samples (x ≤0.33 ) exhibits a second magnetization peak (SMP), which sustains high Jc at high H and high T , exceeding 105A /c m2 at T = 25 K and μ0H = 6 T for x = 0.30 . On the other hand, the SMP is missing in the optimally (x ˜ 0.36 -0.40 ) and overdoped (x ˜ 0.50 ) samples and consequently Jc rapidly decreases by more than one order of magnitude, although the change in Tc is within a few K. (2) For Co-Ba122, the SMP is always present over the entire superconducting (SC) dome from the underdoped (x ˜ 0.05 ) to the overdoped (x ˜ 0.12 ) region. However, the magnitude of Jc significantly changes with x , exhibiting a sharp maximum at x ˜ 0.057 , which is a slightly underdoped composition for Co-Ba122. (3) For P-Ba122, the highest Jc is attained at x = 0.30 , corresponding to the highest Tc composition. For the overdoped samples, the MHL is characterized by a SMP located close to the irreversibility field Hirr. Common to the three doping variations, Jc becomes highest at the underdoping side of the SC dome near the phase boundary between the SC phase and the antiferromagnetic-orthorhombic (AFO) phase. Also, the peak appears in a narrow range of doping, distinct from the Tc dome with a broad maximum. These similarities in the three cases indicate that the observed doping dependence of Jc is intrinsic to the BaF e2A s2 -based superconductors. The

  6. 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.

  7. 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

  8. 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...

  9. 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.

  10. 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.

  11. Technologies for greywater recycling in buildings

    OpenAIRE

    Laine, Anu Talvikki

    2001-01-01

    The potential of four pilot-scale wastewater treatment processes for in-building greywater recycling has been assessed. The evaluation of three membrane bioreactors (MBRs) and a biological aerated filter (BAF) was principally with reference to the non-potable water reuse quality standards. In the steady-state trials the feedwater quality was changed from synthetic greywater to blackwater (primary sewage influent) simulating the variability of domestic wastewater. The submerged MBR met bot...

  12. Filter holder and gasket assembly for candle or tube filters

    Science.gov (United States)

    Lippert, Thomas Edwin; Alvin, Mary Anne; Bruck, Gerald Joseph; Smeltzer, Eugene E.

    1999-03-02

    A filter holder and gasket assembly for holding a candle filter element within a hot gas cleanup system pressure vessel. The filter holder and gasket assembly includes a filter housing, an annular spacer ring securely attached within the filter housing, a gasket sock, a top gasket, a middle gasket and a cast nut.

  13. Toward an understanding of the effects of agitation and aeration on growth and laccases production by Pleurotus ostreatus.

    Science.gov (United States)

    Tinoco-Valencia, Raunel; Gómez-Cruz, Cristina; Galindo, Enrique; Serrano-Carreón, Leobardo

    2014-05-10

    Mycelial growth and laccase production by Pleurotus ostreatus CP50 cultured in a 10-L mechanically agitated bioreactor were assessed through a 2(3) factorial experimental design. The main effects and interactions of three factors (agitation, aeration and copper induction) over five responses (μ, αLacc, βLacc, maximal volumetric laccase activity and maximal biomass concentration) were analyzed. P. ostreatus growth was significantly improved when culturing was conducted with high agitation (5.9kW/m(3)s) and aeration flow (0.5vvm) rates. Under the experimental conditions evaluated, no evidence of hydrodynamic stress affecting fungal growth was observed. However, the high agitation and aeration conditions were detrimental for the growth-associated laccase production constant (αLacc), leading to a very complex optimization of the process. The maximal laccase volumetric activity (1.2 and 3.8U/ml for non-induced and copper-induced cultures, respectively) was observed when the culturing was performed at a low agitation rate (0.9kW/m(3)s) and a high aeration flow rate (0.5vvm). Laccase proteolysis may explain the complex interactions observed between agitation and aeration and the effects of these factors on the laccase volumetric activity observed in the cultures.

  14. Coupling of bio-PRB and enclosed in-well aeration system for remediation of nitrobenzene and aniline in groundwater.

    Science.gov (United States)

    Liu, Na; Ding, Feng; Wang, Liu; Liu, Peng; Yu, Xiaolong; Ye, Kang

    2016-05-01

    A laboratory-scale bio-permeable reactive barrier (bio-PRB) was constructed and combined with enclosed in-well aeration system to treat nitrobenzene (NB) and aniline (AN) in groundwater. Batch-style experiments were first conducted to evaluate the effectiveness of NB and AN degradation, using suspension (free cells) of degrading consortium and immobilized consortium by a mixture of perlite and peat. The NB and AN were completely degraded in 4 mg L(-1) when the aeration system was applied into the bio-PRB system. The NB and AN were effectively removed when the aeration system was functional in the bio-PRB. The removal efficiency decreased when the aeration system malfunctioned for 20 days, thus indicating that DO was an important factor for the degradation of NB and AN. The regain of NB and AN removal after the malfunction indicates the robustness of degradation consortium. No original organics and new formed by-products were observed in the effluent. The results indicate that NB and AN in groundwater can be completely mineralized in a bio-PRB equipped with enclosed in-well aeration system and filled with perlite and peat attached with degrading consortium.

  15. Vinyl acetate degradation by Brevibacillus agri isolated from a slightly aerated methanogenic reactor.

    Science.gov (United States)

    Lara-Mayorga, I; Durán-Hinojosa, U; Arana-Cuenca, A; Monroy-Hermosillo, O; Ramírez-Vives, F

    2010-01-01

    In a previous paper, the authors showed that a slight aeration of a methanogenic reactor treating wastewater from the manufacture of polymeric resins could improve its performance, by increasing or allowing the removal of some of its contaminants, including vinyl acetate (VA). This paper reports the isolation under aerobic conditions of a VA-biodegrading axenic culture (strain C1) retrieved from the sludge of a slightly aerated methanogenic reactor at 1 mg L(-1) d(-1) of dissolved oxygen (DO). The axenic culture obtained was phenotypically (morphology, biochemical properties, VA consumption kinetics) and phylogenetically characterized. It formed white colonies with a branched and flat morphology on solid medium. The cell morphology of the isolate was bacillus with round endings and flagellate. The cells could form chains and were stained Gram-negative. The isolate required simple nutritional elements and had a growth rate of 0.024 h(-1). The phylogenetical analysis showed that the aerobic bacterium was identified as Brevibacillus agri, with 99.3% similarity. The VA consumption kinetics in the methanogenic sludge were: volumetric consumption rate (rVA) of 1.74 +/- 0.2 mg L(-1) h(-1), maximum specific consumption rate (qVAmax) of 3.98 mg g(-1) volatile suspended solids (VSS) h(-1) and affinity constant (Ks) of 457.1 mg L(-1). The same parameters in the axenic culture were 1.69 +/- 0.04 mg L(-1) (h-1), 4.09 mg g(-1) dry weight h(-1) and 421.9 mg L(-1), respectively. These results show evidence that the aerobic isolated bacterium, identified as Brevibacillus agri, carried out the VA hydrolysis in the slightly aerated methanogenic sludge, which is the limiting step in the degradation of this compound.

  16. Fast Anisotropic Gauss Filtering

    NARCIS (Netherlands)

    Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.; Heyden, A.; Sparr, G.; Nielsen, M.; Johansen, P.

    2002-01-01

    We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction followed by a one dimensional filter in a non-orthogonal direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computin

  17. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Tugwell, Peter; Boers, Maarten; D'Agostino, Maria-Antonietta;

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter requires that criteria be met to demonstrate that the outcome instrument meets the cr...

  18. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Wells, George; Beaton, Dorcas E; Tugwell, Peter;

    2014-01-01

    The "Discrimination" part of the OMERACT Filter asks whether a measure discriminates between situations that are of interest. "Feasibility" in the OMERACT Filter encompasses the practical considerations of using an instrument, including its ease of use, time to complete, monetary costs, and inter...

  19. Vena cava filter; Vena-cava-Filter

    Energy Technology Data Exchange (ETDEWEB)

    Helmberger, T. [Klinikum Bogenhausen, Institut fuer Diagnostische und Interventionelle Radiologie und Nuklearmedizin, Muenchen (Germany)

    2007-05-15

    Fulminant pulmonary embolism is one of the major causes of death in the Western World. In most cases, deep leg and pelvic venous thrombosis are the cause. If an anticoagulant/thrombotic therapy is no longer possible or ineffective, a vena cava filter implant may be indicated if an embolism is threatening. Implantation of the filter is a simple and safe intervention. Nevertheless, it is necessary to take into consideration that the data base for determining the indications for this treatment are very limited. Currently, a reduction in the risk of thromboembolism with the use of filters of about 30%, of recurrences of almost 5% and fatal pulmonary embolism of 1% has been reported, with a risk of up to 20% of filter induced vena cava thrombosis. (orig.) [German] Die fulminante Lungenembolie zaehlt zu den Haupttodesursachen in der westlichen Welt. In der Mehrzahl der Faelle sind tiefe Bein- und Beckenvenenthrombosen ursaechlich verantwortlich. Ist eine antikoagulative/-thrombotische Therapie nicht (mehr) moeglich oder unwirksam, kann bei drohender Emboliegefahr die Vena-cava-Filterimplantation indiziert sein. Die Filterimplantation ist eine einfache und sehr sichere Intervention. Dennoch muss bei der Indikationsstellung beruecksichtigt werden, dass die Datenlage zur Wirksamkeit sehr limitiert ist. So wird aktuell ueber eine Reduktion des Thrombembolierisikos um 30% bei Embolierezidiven von knapp 5% und fatalen Lungenembolien von 1% unter Filterprophylaxe berichtet, bei einem Risiko von bis zu 20% fuer die filterinduzierte Vena-cava-Thrombose. (orig.)

  20. Microstructural Properties of Single Crystalline PbTe Thin Films Grown on BaF2(111) by Molecular Beam Epitaxy

    Institute of Scientific and Technical Information of China (English)

    SI Jian-Xiao; WU Hui-Zhen; XU Tian-Ning; CAO Chun-Fang; HUANG Zhan-Chao

    2005-01-01

    @@ Single crystal PbTe thin films have been grown on BaF2 (111) by using solid source molecular beam epitaxy.The studies of evolution of the surface morphology with the increasing growth temperature from 375 to 525℃by AFM show that PbTe epilayers exhibit smooth surface morphologies with atomic layer scale roughness and are crack free. It is found that for PbTe grown at 475℃, the morphology is dominated by triangles and the rms roughness is 3.987nm. Compared to the rms roughnesses of 0.432nm and 0.759nm for the samples grown at 375 and 525℃ respectively, the surface of the PbTe layer grown at 475℃ is much rougher. This roughening transition is due to the interaction between the elastic relaxation and the plastic relaxation during the strain relaxation process. In contrast to the result of the morphology that the PbTe epitaxial layer grown at 375℃ has most smooth surface, as observed from the line width of x-ray diffraction curves at higher growth temperature improves the crystal quality of the single-crystalline PbTe layer.

  1. Enhanced processability of ZrF4-BaF2-LaF3-AlF3-NaF glass in microgravity

    Science.gov (United States)

    Torres, Anthony; Ganley, Jeff; Maji, Arup; Tucker, Dennis; Starodubov, Dmitry

    2013-06-01

    Fluorozirconate glasses, such as ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF), have the potential for optical transmission from 0.3 μm in the UV to 7 μm in the IR region. However, crystallites formed during the fiber drawing process prevent this glass from achieving its desired transmission range. The temperature at which the glass can be drawn into a fiber is known as the working range, defined as (Tx - Tg), bounded by the glass transition temperature (Tg) and the crystallization temperature (Tx). In contrast to silica glasses, the working temperature range for ZBLAN glass is extremely narrow. Multiple ZBLAN samples were subject to a heating and quenching test apparatus on the parabolic aircraft, under a controlled 0-g and hyper-g environment and compared with 1-g ground tests. The microgravity duration on board Zero-G Corporation parabolic aircraft is approximately 20 seconds and the hyper-g intervals are approximately 56 seconds. Optical microscopy examination elucidates crystal growth in ZBLAN is suppressed when processed in a microgravity environment. The crystallization temperature, Tx, at which crystals form increased, therefore, significantly broadening the working temperature range for ZBLAN.

  2. EXPERIMENTAL STUDY ON THE GAS-LIQUID FLOW IN THE MEMBRANE MICROPORE AERATION BIOREACTOR

    Directory of Open Access Journals (Sweden)

    DONG LIU

    2008-12-01

    Full Text Available Particle Image Velocimetry (PIV has been developed to measure the typical two-phase flow of various work conditions in Membrane Micropore Aeration Bioreactor (MMAB. The fluid phase is separated out using image processing techniques, which provides accurate measurements for the Bioreactor’s flow field, and makes it possible for quantitative analysis of the momentum exchange, heat exchange and the process of micro-admixture. The experimental method PIV used in this paper can preferably measure the complex flow in the reactor and initiates a new approach for the bioreactor design which mainly depends on experience at present.

  3. Removal of arsenic from contaminated groundwater with application of iron electrodissolution, aeration and sand filtration

    DEFF Research Database (Denmark)

    Kowalski, Krysztof; Arturi, Kasia; Søgaard, Erik Gydesen

    2014-01-01

    The results from a new water treatment system for arsenic removal are presented. The technology is based on the employment of an electrolytic iron dissolution and efficient aeration procedure prior to sand filtration. The treatment was introduced and investigated in a pilot scale plant and full...... scale waterworks. The pilot scale results showed a possibility for an efficient arsenic removal from spiked solutions (with As in the range of 50–85 μg/L) depending on the process conditions (flow and applied current). In the waterworks where the system was implemented for a period of 14 months...

  4. Filter cake breaker systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Marcelo H.F. [Poland Quimica Ltda., Duque de Caxias, RJ (Brazil)

    2004-07-01

    Drilling fluids filter cakes are based on a combination of properly graded dispersed particles and polysaccharide polymers. High efficiency filter cakes are formed by these combination , and their formation on wellbore walls during the drilling process has, among other roles, the task of protecting the formation from instantaneous or accumulative invasion of drilling fluid filtrate, granting stability to well and production zones. Filter cake minimizes contact between drilling fluid filtrate and water, hydrocarbons and clay existent in formations. The uniform removal of the filter cake from the entire interval is a critical factor of the completion process. The main methods used to breaking filter cake are classified into two groups, external or internal, according to their removal mechanism. The aim of this work is the presentation of these mechanisms as well their efficiency. (author)

  5. Weighted guided image filtering.

    Science.gov (United States)

    Li, Zhengguo; Zheng, Jinghong; Zhu, Zijian; Yao, Wei; Wu, Shiqian

    2015-01-01

    It is known that local filtering-based edge preserving smoothing techniques suffer from halo artifacts. In this paper, a weighted guided image filter (WGIF) is introduced by incorporating an edge-aware weighting into an existing guided image filter (GIF) to address the problem. The WGIF inherits advantages of both global and local smoothing filters in the sense that: 1) the complexity of the WGIF is O(N) for an image with N pixels, which is same as the GIF and 2) the WGIF can avoid halo artifacts like the existing global smoothing filters. The WGIF is applied for single image detail enhancement, single image haze removal, and fusion of differently exposed images. Experimental results show that the resultant algorithms produce images with better visual quality and at the same time halo artifacts can be reduced/avoided from appearing in the final images with negligible increment on running times.

  6. Robustifying Vector Median Filter

    Directory of Open Access Journals (Sweden)

    Valentín Gregori

    2011-08-01

    Full Text Available This paper describes two methods for impulse noise reduction in colour images that outperform the vector median filter from the noise reduction capability point of view. Both methods work by determining first the vector median in a given filtering window. Then, the use of complimentary information from componentwise analysis allows to build robust outputs from more reliable components. The correlation among the colour channels is taken into account in the processing and, as a result, a more robust filter able to process colour images without introducing colour artifacts is obtained. Experimental results show that the images filtered with the proposed method contain less noisy pixels than those obtained through the vector median filter. Objective measures demonstrate the goodness of the achieved improvement.

  7. Naive Bayesian for Email Filtering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper presents a method of email filter based on Naive Bayesian theory that can effectively filter junk mail and illegal mail. Furthermore, the keys of implementation are discussed in detail. The filtering model is obtained from training set of email. The filtering can be done without the users specification of filtering rules.

  8. Electron paramagnetic resonance and optical spectroscopy of Yb sup 3 sup + ions in SrF sub 2 and BaF sub 2; an analysis of distortions of the crystal lattice near Yb sup 3 sup +

    CERN Document Server

    Falin, M L; Latypov, V A; Leushin, A M

    2003-01-01

    SrF sub 2 and BaF sub 2 crystals, doped with the Yb sup 3 sup + ions, have been investigated by electron paramagnetic resonance and optical spectroscopy. As-grown crystals of SrF sub 2 and BaF sub 2 show the two paramagnetic centres for the cubic (T sub c) and trigonal (T sub 4) symmetries of the Yb sup 3 sup + ions. Empirical diagrams of the energy levels were established and the potentials of the crystal field were determined. Information was obtained on the SrF sub 2 and BaF sub 2 phonon spectra from the electron-vibrational structure of the optical spectra. The crystal field parameters were used to analyse the crystal lattice distortions in the vicinity of the impurity ion and the F sup - ion compensating for the excess positive charge in T sub 4. Within the frames of a superposition model, it is shown that three F sup - ions from the nearest surrounding cube, located symmetrically with respect to the C sub 3 axis from the side of the ion-compensator, approach the impurity ion and cling to the axis of the...

  9. The quasi-binary phase diagram BaF2-BaBr2 and its relation to the x-ray storage phosphor BaFBr : Eu2+

    Science.gov (United States)

    Kolb, R.; Schlapp, M.; Hesse, S.; Schmechel, R.; von Seggern, H.; Fasel, C.; Riedel, R.; Ehrenberg, H.; Fuess, H.

    2002-08-01

    In order to understand the formation and stoichiometry of the x-ray storage phosphor BaFBr : Eu2+, the phase diagram of the quasi-binary BaF2-BaBr2 system has been investigated. The phase diagram was obtained by means of differential thermal analysis and temperature controlled x-ray diffraction experiments. The resulting phase diagram indicates that BaFBr forms a compound with no detectable solid solubility for neither BaF2 nor BaBr2. Experiments to obtain non-stoichiometric BaFBr via the synthesis route using BaF2 and NH4Br as proposed in the literature could not be verified. It will be shown that the type of colour centre created during x-ray irradiation is related to the non-stoichiometry of the starting compositions before sintering. A surplus of either barium fluoride or barium bromide during sintering allows the controlled formation of F(Br-)- and F(F-)-centres, respectively.

  10. Linking biofilm growth to fouling and aeration performance of fine-pore diffuser in activated sludge.

    Science.gov (United States)

    Garrido-Baserba, Manel; Asvapathanagul, Pitiporn; McCarthy, Graham W; Gocke, Thomas E; Olson, Betty H; Park, Hee-Deung; Al-Omari, Ahmed; Murthy, Sudhir; Bott, Charles B; Wett, Bernhard; Smeraldi, Joshua D; Shaw, Andrew R; Rosso, Diego

    2016-03-01

    Aeration is commonly identified as the largest contributor to process energy needs in the treatment of wastewater and therefore garners significant focus in reducing energy use. Fine-pore diffusers are the most common aeration system in municipal wastewater treatment. These diffusers are subject to fouling and scaling, resulting in loss in transfer efficiency as biofilms form and change material properties producing larger bubbles, hindering mass transfer and contributing to increased plant energy costs. This research establishes a direct correlation and apparent mechanistic link between biofilm DNA concentration and reduced aeration efficiency caused by biofilm fouling. Although the connection between biofilm growth and fouling has been implicit in discussions of diffuser fouling for many years, this research provides measured quantitative connection between the extent of biofouling and reduced diffuser efficiency. This was clearly established by studying systematically the deterioration of aeration diffusers efficiency during a 1.5 year period, concurrently with the microbiological study of the biofilm fouling in order to understand the major factors contributing to diffuser fouling. The six different diffuser technologies analyzed in this paper included four different materials which were ethylene-propylene-diene monomer (EPDM), polyurethane, silicone and ceramic. While all diffusers foul eventually, some novel materials exhibited fouling resistance. The material type played a major role in determining the biofilm characteristics (i.e., growth rate, composition, and microbial density) which directly affected the rate and intensity at what the diffusers were fouled, whereas diffuser geometry exerted little influence. Overall, a high correlation between the increase in biofilm DNA and the decrease in αF was evident (CV aeration efficiency, the research was able to show quantitatively the causal connection between bacterial fouling and energy wastage during

  11. Oxygen air enrichment through composite membrane: application to an aerated biofilm reactor

    Directory of Open Access Journals (Sweden)

    A. C. Cerqueira

    2013-12-01

    Full Text Available A highly permeable composite hollow-fibre membrane developed for air separation was used in a membrane aerated biofilm reactor (MABR. The composite membrane consisted of a porous support layer covered with a thin dense film, which was responsible for oxygen enrichment of the permeate stream. Besides oxygen enrichment capability, dense membranes overcome major operational problems that occur when using porous membranes for oxygen transfer to biofilms. Air flow rate and oxygen partial pressure inside the fibres were the variables used to adjust the oxygen transfer rate. The membrane aerated biofilm reactor was operated with hydraulic retention times (HRT ranging from 1 to 4 hours. High organic load removal rates, like 6.5 kg.m-3.d-1, were achieved due to oxygen transfer rates as high as 107 kg.m-3.d-1. High COD removals, with improved oxygen transfer efficiency, indicate that a MABR is a compact alternative to the conventional activated sludge process and that the selected membrane is suitable for further applications.

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

    Directory of Open Access Journals (Sweden)

    Keli He

    2016-09-01

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

  13. Simultaneous removal of COD and nitrogen using a novel carbon-membrane aerated biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A membrane aerated biofilm reactor is a promising technology for wastewater treatment. In this study, a carbon-membrane aerated biofilm reactor (CMABR) has been developed, to remove carbon organics and nitrogen simultaneously from one reactor. The results showed that CMABR has a high chemical oxygen demand (COD) and nitrogen removal efficiency, as it is operated with a hydraulic retention time (HRT) of 20 h, and it also showed a perfect performance, even if the HRT was shortened to 12 h. In this period, the removal efficiencies of COD, ammonia nitrogen (NH4+-N), and total nitrogen (TN) reached 86%, 94%, and 84%, respectively. However,the removal efficiencies of NH4+-N and TN declined rapidly as the HRT was shortened to 8 h. This is because of the excessive growth of biomass on the nonwoven fiber and very high organic loading rate. The fluorescence in situ hybridization (FISH) analysis indicated that the ammonia oxidizing bacteria (AOB) were mainly distributed in the inner layer of the biofilm. The coexistence of AOB and eubacteria in one biofilm can enhance the simultaneous removal of COD and nitrogen.

  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. Growth and final product formation by Bifidobacterium infantis in aerated fermentations.

    Science.gov (United States)

    González, R; Blancas, A; Santillana, R; Azaola, A; Wacher, C

    2004-10-01

    Fermentation conditions were developed to allow Bifidobacterium infantis to grow in the presence of air. Batch fermentations in TPYG medium, starting from anoxic conditions followed by the application of low airflow rates [0.02-0.1 air volume, per liquid media volume, per minute (vvm)], were analyzed for growth, oxygen uptake, and product formation by the bacterium. Under all aerated fermentations, B. infantis showed high aerotolerance, with a maximum oxygen-specific consumption rate of 0.34 mmol oxygen per gram dry cell weight per hour in the presence of 0.06 vvm. Similar growth yields were obtained under oxic and anoxic conditions (0.11-0.13 and 0.11 g dry cell weight per mmol glucose, respectively). Oxygen also influenced metabolite formation since lactate production and its molar relation to acetate increased and formate decreased with aeration rate. Under anoxic conditions, a maximum concentration of 8.1 mM lactate and an acetate/lactate ratio of 3.5:1 were obtained, while under oxic conditions the lactate concentration increased more than two-fold and the acetate/lactate molar ratio decreased to 1.5:1. The possibility of balancing acetate/lactate molar ratios for organoleptic purposes as well as for obtaining good growth under microaerated conditions was demonstrated.

  16. Preparation of New Cementitious System using Fly Ash and Dehydrated Autoclaved Aerated Concrete

    Institute of Scientific and Technical Information of China (English)

    SHUI Zhonghe; LU Jianxin; TIAN Sufang; SHEN Peiliang; DING Sha

    2014-01-01

    We experimentally studied the interaction between pozzolanic material (fly ash) and dehydrated autoclaved aerated concrete (DAAC). The DAAC powder was obtained by grinding aerated concrete waste to particles finer than 75μm and was then heated to temperatures up to 900℃. New cementitious material was prepared by proportioning fly ash and DAAC, named as AF. X-ray diffraction (XRD) was employed to identify the crystalline phases of DAAC before and after rehydration. The hydration process of AF was analyzed by the heat of hydration and non-evaporable water content (Wn). The experimental results show that the highest reactivity of DAAC can be obtained by calcining the powder at 700℃and the dehydrated products are mainlyβ-C2S and CaO. The cumulative heat of hydration and Wn was found to be strongly dependent on the replacement level of fly ash, increasing the replacement level of fly ash lowered them in AF. The strength contribution rates on pozzolanic effect of fly ash in AF are always negative, showing a contrary tendency of that of cement-fly ash system.

  17. Microfaunal indicators, Ciliophora phylogeny and protozoan population shifts in an intermittently aerated and fed bioreactor.

    Science.gov (United States)

    Ntougias, Spyridon; Tanasidis, Spartakos; Melidis, Paraschos

    2011-02-28

    Microfauna community structure was examined in the mixed liquor of a bench-scale bioreactor equipped with an intermittent aeration and feeding system. The reactor was operated under an intermittent aeration of 25 min in every 1 h and varying feeding conditions (0.264, 0.403 and 0.773 kg BOD(5)/m(3) d). A total of 14 protozoan and metazoan taxa were identified by microscopic examination. Sessile ciliates, followed by crawling ciliates, were the major protozoan groups under 0.403 kg BOD(5)/m(3) d organic loading conditions, while sessile ciliate population was remarkably increased under an organic loading of 0.773 kg BOD(5)/m(3) d. Principal Component Analysis and Pearson correlation coefficient tests were performed in order to reveal relationships between microfauna community and operational parameters. Ciliophora specific-18S rRNA gene clone library was constructed to identify ciliate diversity under 0.773 kg BOD(5)/m(3) d organic loading conditions. Ciliophora diversity consisted of members of Aspidiscidae, Epistylidae, Opisthonectidae and Vorticellidae, with the majority of the clones being associated with the species Vorticella fusca. At least one novel phylogenetic linkage among Ciliophora was identified. Comparisons made after molecular characterization and microscopic examination of Ciliophora community showed that the estimation of broad ciliate groups is useful for ecological considerations and evaluation of the operational conditions in wastewater treatment plants.

  18. Microfaunal indicators, Ciliophora phylogeny and protozoan population shifts in an intermittently aerated and fed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Ntougias, Spyridon, E-mail: sntougia@env.duth.gr [Democritus University of Thrace, Department of Environmental Engineering, Laboratory of Wastewater Management and Treatment Technologies, Vas. Sofias 12, 67100 Xanthi (Greece); Tanasidis, Spartakos; Melidis, Paraschos [Democritus University of Thrace, Department of Environmental Engineering, Laboratory of Wastewater Management and Treatment Technologies, Vas. Sofias 12, 67100 Xanthi (Greece)

    2011-02-28

    Microfauna community structure was examined in the mixed liquor of a bench-scale bioreactor equipped with an intermittent aeration and feeding system. The reactor was operated under an intermittent aeration of 25 min in every 1 h and varying feeding conditions (0.264, 0.403 and 0.773 kg BOD{sub 5}/m{sup 3} d). A total of 14 protozoan and metazoan taxa were identified by microscopic examination. Sessile ciliates, followed by crawling ciliates, were the major protozoan groups under 0.403 kg BOD{sub 5}/m{sup 3} d organic loading conditions, while sessile ciliate population was remarkably increased under an organic loading of 0.773 kg BOD{sub 5}/m{sup 3} d. Principal Component Analysis and Pearson correlation coefficient tests were performed in order to reveal relationships between microfauna community and operational parameters. Ciliophora specific-18S rRNA gene clone library was constructed to identify ciliate diversity under 0.773 kg BOD{sub 5}/m{sup 3} d organic loading conditions. Ciliophora diversity consisted of members of Aspidiscidae, Epistylidae, Opisthonectidae and Vorticellidae, with the majority of the clones being associated with the species Vorticella fusca. At least one novel phylogenetic linkage among Ciliophora was identified. Comparisons made after molecular characterization and microscopic examination of Ciliophora community showed that the estimation of broad ciliate groups is useful for ecological considerations and evaluation of the operational conditions in wastewater treatment plants.

  19. Large eddy simulation of dilute bubbly turbulent flows for aerating hydrofoils

    Science.gov (United States)

    Hajit, Mohammad; Sotiropoulos, Fotis

    2014-11-01

    We have proposed a formulation for the large eddy simulation of dilute bubbly flows by converting the governing equations to a more loosely-coupled form. This formulation provides an efficient numerical procedure for two-way coupling of bubbly flows at low gas holdups. Subgrid-scale turbulence modeling is based on the dynamic procedure of Germano for the liquid phase and the Jakobson approach for the gas phase. Wall-modeling is implemented using the method of Cabot & Moin. Our approach is employed to simulate flow over aerating hydrofoils at different angles of attack. A structured body-fitted C-grid is employed for domain discretization. Validation of our computational code, for C-grids, is carried out by simulating single-phase flows over a NACA0012 airfoil (20° AOA) with laminar flow and an E387 airfoil (6° AOA) with turbulent flow. Comparisons with available computational and experimental data in terms of time averaged drag coefficient, lift coefficient, separation bubble length, and reattachment point proves the validity of our computational code. The aerating hydrofoil simulation utilizes a NACA0015 hydrofoil, for which experiments were carried out at Saint Anthony Falls Laboratory. Comparisons between computational and experimental datasets show promising results. This work is supported by the U.S. Dept. of Energy and the Hydro Reasearch Foundation.

  20. High rate nitrogen removal in an alum sludge-based intermittent aeration constructed wetland.

    Science.gov (United States)

    Hu, Yuansheng; Zhao, Yaqian; Zhao, Xiaohong; Kumar, Jeyakumar L G

    2012-04-17

    A new development on treatment wetland technology for the purpose of achieving high rate nitrogen removal from high strength wastewater has been made in this study. The laboratory scale alum sludge-based intermittent aeration constructed wetland (AlS-IACW) was integrated with predenitrification, intermittent aeration, and step-feeding strategies. Results obtained from 280 days of operation have demonstrated extraordinary nitrogen removal performance with mean total nitrogen (TN) removal efficiency of 90% under high N loading rate (NLR) of 46.7 g N m(-2) d(-1). This performance was a substantial improvement compared to the reported TN removal performance in literature. Most significantly, partial nitrification and simultaneous nitrification denitrification (SND) via nitrite was found to be the main nitrogen conversion pathways in the AlS-IACW system under high dissolved oxygen concentrations (3-6 mg L(-1)) without specific control. SND under high dissolved oxygen (DO) brings high nitrogen conversion rates. Partial nitrification and SND via nitrite can significantly reduce the demand for organic carbon compared with full nitrification and denitrification via nitrate (up to 40%). Overall, these mechanisms allow the system to maintaining efficient and high rate TN removal even under carbon limiting conditions.

  1. Improving aeration for efficient oxygenation in sea bass sea cages. Blood, brain and gill histology

    Directory of Open Access Journals (Sweden)

    Berillis Panagiotis

    2016-01-01

    Full Text Available An air diffusion based system (Airx was developed to control the dissolved oxygen levels in aquaculture sea cages. The system was introduced and then tested for 37 days in a sea bass sea cage (aerated cage. A second sea bass sea cage, without the AirX, was used as a control. Oxygen levels were measured in both cages at the start of the trial, before the AirX system was introduced, and during the working period of the AirX system. Fish samples were collected 15 days after the AirX system was introduced and at the end of the experiment. Blood smears were prepared and examined microscopically. Erythrocyte major axis, minor axis and area of fish erythrocytes were measured. Leucocyte differentiation was also examined. In the control cage, the fish had significantly larger red blood cells when compared with the red blood cells of the fish in the aerated cage. Histological examination of the gills and brain revealed no morphological differences or alterations between the two groups of fish. This study demonstrated that an air diffuser system could improve the water quality of fish farmed in sea cages and enhance sea bass physiological performance, especially if DO levels fall below 60% oxygen saturation.

  2. Derivative free filtering using Kalmtool

    DEFF Research Database (Denmark)

    Bayramoglu, Enis; Hansen, Søren; Ravn, Ole;

    2010-01-01

    In this paper we present a toolbox enabling easy evaluation and comparison of different filtering algorithms. The toolbox is called Kalmtool 4 and is a set of MATLAB tools for state estimation of nonlinear systems. The toolbox contains functions for extended Kalman filtering as well as for DD1...... filter and the DD2 filter. It also contains functions for Unscented Kalman filters as well as several versions of particle filters. The toolbox requires MATLAB version 7, but no additional toolboxes are required....

  3. Autoclaved aerated concrete masonry with external insulation. Features of moisture conditions during the initial period of operation (rus

    Directory of Open Access Journals (Sweden)

    Kuptaraeva P.D.

    2011-12-01

    Full Text Available Building designs at the moment of commissioning include the initial (building and technological moisture. Thermal insulation systems influence on the yield of the initial moisture from the structures. However, there are no specific design requirements about determining initial moisture content in insulation systems.In this article the features of the initial period of operation on an example of aerated concrete are defined: the results of field surveys and calculations are shown and compared. On the basis of this comparison basic advice on the accounting features of the initial period of operation of autoclaved aerated concrete structures with external insulation are given.

  4. Randomized Filtering Algorithms

    DEFF Research Database (Denmark)

    Katriel, Irit; Van Hentenryck, Pascal

    2008-01-01

    of AllDifferent and is generalization, the Global Cardinality Constraint. The first delayed filtering scheme is a Monte Carlo algorithm: its running time is superior, in the worst case, to that of enforcing are consistency after every domain event, while its filtering effectiveness is analyzed...... in the expected sense. The second scheme is a Las Vegas algorithm using filtering triggers: Its effectiveness is the same as enforcing are consistency after every domain event, while in the expected case it is faster by a factor of m/n, where n and m are, respectively, the number of nodes and edges...

  5. EMI filter design

    CERN Document Server

    Ozenbaugh, Richard Lee

    2011-01-01

    With today's electrical and electronics systems requiring increased levels of performance and reliability, the design of robust EMI filters plays a critical role in EMC compliance. Using a mix of practical methods and theoretical analysis, EMI Filter Design, Third Edition presents both a hands-on and academic approach to the design of EMI filters and the selection of components values. The design approaches covered include matrix methods using table data and the use of Fourier analysis, Laplace transforms, and transfer function realization of LC structures. This edition has been fully revised

  6. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  7. Air Filter Simulation by Geodict

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-peng; Kitai Kim; Changhwan Lee; Jooyong Kim

    2006-01-01

    In this paper, we discussed the relationship of filter efficiency and pressure drop with the porosity, fiber diameter and filter thickness by Geodict. We found that filter efficiency will increase when filter porosity and fiber diameter decreasing or filter thickness increasing. And the pressure drop has a linear relationship with filter thickness and non-linear relationship with filter porosity and fiber diameter. We also compared the simulation results with the real test results by TSI 3160. Although there are some differences, I think Geodict can be used to predict filter efficiency and pressure drop.

  8. Study on the test of oxygen effect of aerator in pond%增氧机池塘增氧效果试验的研究

    Institute of Scientific and Technical Information of China (English)

    张祝利; 顾海涛; 何雅萍; 门涛; 吴为国

    2012-01-01

    研究不同型式的增氧机性能,可使生产者根据不同养殖对象与模式针对溶氧的需求,选择配置合适的增氧方式.通过对使用最为广泛的叶轮式、水车式、射流式和曝气式增氧机产品性能的池塘实效试验,分析比较各类增氧机性能、工作特性和适用范围.结果表明,养殖水体溶解氧主要来自浮游植物的光合作用;叶轮式、水车式和射流式增氧机应用于服务水域,其增氧能力远远不能满足该水域养殖鱼类的氧需求,但可满足养殖鱼类的应急氧需求;曝气式增氧机因没有应急增氧作用和水体搅拌能力而不适合四大家鱼等常规鱼种的养殖需要.%With the development of aquaculture aeration technology,the continuous appearance of various types of aerobic machineries adapts to the needs of different aquaculture.Researching the performance of different types of aerators can help the producers select appropriate aeration manners,which is based on the demand of dissolved oxygen according to different culture species and models.According to the experiment of the effect of impeller aerator,paddlewheel aerator,jet aerators and aeration aerator in the pond which are most widely used,we analyzed the aerator performance,operating characteristics and applicability.The result showed that the dissolved oxygen of aquaculture water mainly comes from the photosynthesis of phytoplankton.When impeller aerator,paddlewheel aerator and jet aerators apply to its service water,their aerobic capacities are far from the oxygen demands of the hshes which cultured in the water,however,it can meet the emergency oxygen demands of cultured fishes.Aeration aerator is not suitable for culturing the four major Chinese carps because it is lack of emergency oxygen effect and water mixing capacity.

  9. HEPA air filter (image)

    Science.gov (United States)

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  10. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Kirwan, John R; Boers, Maarten; Hewlett, Sarah

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter presupposes an explicit framework for identifying the relevant core outcomes that are......OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter presupposes an explicit framework for identifying the relevant core outcomes...... that are universal to all studies of the effects of intervention effects. There is no published outline for instrument choice or development that is aimed at measuring outcome, was derived from broad consensus over its underlying philosophy, or includes a structured and documented critique. Therefore, a new proposal...

  11. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    D'Agostino, Maria-Antonietta; Boers, Maarten; Kirwan, John

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides a framework for the validation of outcome measures for use in rheumatology clinical research. However, imaging and biochemical measures may face additional validation challenges because of their technical nature. The Imagin...

  12. Paul Rodgersi filter Kohilas

    Index Scriptorium Estoniae

    2000-01-01

    28. I Kohila keskkoolis kohaspetsiifiline skulptuur ja performance "Filter". Kooli 130. aastapäeva tähistava ettevõtmise eesotsas oli skulptor Paul Rodgers ja kaks viimase klassi noormeest ئ Marko Heinmäe, Hendrik Karm.

  13. Cryogenic coaxial microwave filters

    CERN Document Server

    Tancredi, G; Meeson, P J

    2014-01-01

    At millikelvin temperatures the careful filtering of electromagnetic radiation, especially in the microwave regime, is critical for controlling the electromagnetic environment for experiments in fields such as solid-state quantum information processing and quantum metrology. We present a design for a filter consisting of small diameter dissipative coaxial cables that is straightforward to construct and provides a quantitatively predictable attenuation spectrum. We describe the fabrication process and demonstrate that the performance of the filters is in good agreement with theoretical modelling. We further perform an indicative test of the performance of the filters by making current-voltage measurements of small, underdamped Josephson Junctions at 15 mK and we present the results.

  14. Performance of a biofilter system with agave fiber filter media for municipal wastewater treatment.

    Science.gov (United States)

    Vigueras-Cortés, Juan Manuel; Villanueva-Fierro, Ignacio; Garzón-Zúñiga, Marco Antonio; de Jesús Návar-Cháidez, José; Chaires-Hernández, Isaías; Hernández-Rodríguez, César

    2013-01-01

    Agave plants grow in semi-arid regions and are used for mescal production. However, agave fiber by-products are considered waste materials. Thus, we tested agave fiber as a filter media and biofilm material carrier for removing pollutants from municipal wastewater. Three laboratory-scale biofiltration reactors were used in two trials with five hydraulic loading rates (HLRs = 0.27, 0.54, 0.80, 1.07 and 1.34 m(3) m(-2) d(-1)). One series was conducted using mechanical aeration (0.62 m(3) m(-2) h(-1)). To prevent compaction, decreasing pressure and clogging of the filter media, 4, 8 and 12 internal divisions were evaluated in the biofilter column. After 17 months of continuous operation at an HLR of 0.80 m(3) m(-2) d(-1), the removal efficiencies of the aerated biofilters were 92.0% biochemical oxygen demand, 79.7% chemical oxygen demand, 98.0% helminth eggs, 99.9% fecal coliforms and 91.9% total suspended solids. Statistical analysis showed that the chosen operational parameters significantly influenced the removal efficiencies of the biofilters. The effluent quality obtained under these conditions complied with the Mexican and US EPA standards for agricultural irrigation and green spaces, except for coliforms, which is why the effluents must be disinfected. Thus, agave fiber is a favorable choice for use as a packing material in biofiltration processes.

  15. Mecoprop (MCPP) removal in full-scale rapid sand filters at a groundwater-based waterworks

    Energy Technology Data Exchange (ETDEWEB)

    Hedegaard, Mathilde J., E-mail: mjhe@env.dtu.dk; Arvin, Erik; Corfitzen, Charlotte B.; Albrechtsen, Hans-Jørgen

    2014-11-15

    Contamination by the herbicide mecoprop (MCPP) was detected in groundwater abstraction wells at Kerteminde Waterworks in concentrations up to 0.08 μg/L. MCPP was removed to below detection limit in a simple treatment line where anaerobic groundwater was aerated and subsequently filtered by primary and secondary rapid sand filters. Water quality parameters were measured throughout the waterworks, and they behaved as designed for. MCPP was removed in secondary rapid sand filters — removal was the greatest in the sand filters in the filter line with the highest contact time (63 min). In these secondary sand filters, MCPP concentration decreased from 0.037 μg/L to below the detection limit of 0.01 μg/L. MCPP was removed continuously at different filter depths (0.80 m). Additionally, biodegradation, mineralisation and adsorption were investigated in the laboratory in order to elucidate removal mechanisms in the full-scale system. Therefore, microcosms were set up with filter sand, water and {sup 14}C-labelled MCPP at an initial concentration of 0.2 μg/L. After 24 h, 79–86% of the initial concentration of MCPP was removed. Sorption removed 11–15%, while the remaining part was removed by microbial processes, leading to a complete mineralisation of 13–18%. Microbial removal in the filter sand was similar at different depths of the rapid sand filter, while the amount of MCPP which adsorbed to the filter sand after 48 h decreased with depth from 21% of the initial MCPP in the top layer to 7% in the bottom layer. It was concluded that MCPP was removed in secondary rapid sand filters at Kerteminde Waterworks, to which both adsorption and microbial degradation contributed. - Highlights: • A full-scale groundwater based waterworks was able to remove MCPP. • In the secondary rapid sand filters, MCPP decreased from 0.037 μg/L to < 0.010 μg/L. • The filter sand removed MCPP both by sorption and by microbial degradation. • Microbial removal was unchanged while

  16. The Endogenous Kalman Filter

    OpenAIRE

    Brad Baxter; Liam Graham; Stephen Wright

    2007-01-01

    We relax the assumption of full information that underlies most dynamic general equilibrium models, and instead assume agents optimally form estimates of the states from an incomplete information set. We derive a version of the Kalman filter that is endogenous to agents' optimising decisions, and state conditions for its convergence. We show the (restrictive) conditions under which the endogenous Kalman filter will at least asymptotically reveal the true states. In general we show that incomp...

  17. Holographic interference filters

    Science.gov (United States)

    Diehl, Damon W.

    Holographic mirrors have wavelength-selection properties and thus qualify as a class of interference filters. Two theoretical methods for analyzing such structures are developed. The first method uses Hill's matrix method to yield closed-forms solutions in terms of the Floquet-Bloch waves within a periodic structure. A process is developed for implementing this solution method on a computer, using sparse-matrix memory allocation, numerical root-finding algorithms, and inverse-iteration techniques. It is demonstrated that Hill's matrix method is valid for the analysis of finite and multi-periodic problems. The second method of theoretical analysis is a transfer-matrix technique, which is herein termed thin-film decomposition. It is shown that the two methods of solution yield results that differ by, at worst, a fraction of a percent. Using both calculation techniques, a number of example problems are explored. Of key importance is the construction of a set of curves that are useful for the design and characterization of holographic interference filters. In addition to the theoretical development, methods are presented for the fabrication of holographic interference filters using DuPont HRF-800X001 photopolymer. Central to the exposure system is a frequency-stabilized, tunable dye laser. The types of filters fabricated include single-tone reflection filters, two types of multitone reflection filters, and reflection filters for infrared wavelengths. These filters feature index profiles that are not easily attainable through other fabrication methods. As a supplement to the body of the dissertation, the computer algorithms developed to implement Hill's matrix method and thin-film decomposition are also included as an appendix. Further appendices provide more information on Floquet's theorem and Hill's matrix method. A final appendix presents a design for an infrared laser spectrophotometer.

  18. Microbial degradation of pesticides in rapid sand filters for treatment of drinking water

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Albrechtsen, Hans-Jørgen

    2014-01-01

    to remove pesticides from the water phase and pesticides are detected in 24% of the active Danish waterworks wells. This study aimed at investigating the potential of microbial pesticide removal in rapid sand filters for drinking water treatment. Removal of the pesticides MCPP, bentazone, glyphosate...... of pesticides in the water decreased – MCPP decreased to 42-85%, bentazone to 15-35%, glyphosate to 7-14% and p-nitrophenol 1-3% – from the initial concentration over a period of 6-13 days. The largest microbial removal was observed at Sjælsø waterworks Plant II, where the pesticides were partially mineralised......In Denmark drinking water supply is based on groundwater which is treated by aeration followed by filtration in rapid sand filters. Unfortunately pesticide contamination of the groundwater poses a threat to the water supply, since the simple treatment process at the waterworks is not considered...

  19. Integrated coagulation-trickling filter-ultrafiltration processes for domestic wastewater treatment and reclamation.

    Science.gov (United States)

    Zhao, Qing-Liang; Zhong, Hui-Yuan; Liu, Jin-Li; Liu, Yu

    2012-01-01

    More and more research effort has been put into the development of affordable and high-efficiency wastewater reclamation technology for small communities. In this study, an integrated chemically enhanced primary treatment (CEPT), trickling filter (TF) and ultrafiltration (UF) process was developed with success. Coagulant produced from fly ash was used to enhance primary treatment, while trickling filter packed with coal cinder through four-layer structure without aeration was employed for further removal of COD and ammonium-nitrogen from the CEPT effluent. 95 and 88% removal of COD and ammonium were achieved, while total phosphorus (TP) and suspended solid (SS) were found to be removed completely at a coagulant dosage of 2.5 mL/L in the CEPT-TF-UF system. The product water can meet the standard of Reuse of Recycling Water for Urban Water Quality Standard for Urban Miscellaneous Water Consumption (GB/T 18920-2002, China).

  20. Contactor/filter improvements

    Science.gov (United States)

    Stelman, David

    1989-01-01

    A contactor/filter arrangement for removing particulate contaminants from a gaseous stream includes a housing having a substantially vertically oriented granular material retention member with upstream and downstream faces, a substantially vertically oriented microporous gas filter element, wherein the retention member and the filter element are spaced apart to provide a zone for the passage of granular material therethrough. The housing further includes a gas inlet means, a gas outlet means, and means for moving a body of granular material through the zone. A gaseous stream containing particulate contaminants passes through the gas inlet means as well as through the upstream face of the granular material retention member, passing through the retention member, the body of granular material, the microporous gas filter element, exiting out of the gas outlet means. Disposed on the upstream face of the filter element is a cover screen which isolates the filter element from contact with the moving granular bed and collects a portion of the particulates so as to form a dust cake having openings small enough to exclude the granular material, yet large enough to receive the dust particles. In one embodiment, the granular material is comprised of prous alumina impregnated with CuO, with the cover screen cleaned by the action of the moving granular material as well as by backflow pressure pulses.