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为解决纺织行业水回用问题,采用陶粒和活性炭组合填料生物滤池对锦纶废水二级生物处理出水进行了深度净化,并考察了气水比和水力负荷对曝气生物滤池处理效果的影响.研究结果表明,曝气生物滤池处理效果良好,平均出水COD、NH4 -N和TN分别为32 mg/L、1.5 mg/L和8.1 mg/L.随着气水比的增加,COD和NH4 -N平均去除率相应提高,TN平均去除率先增大后降低,当气水比为2∶1时,COD、NH4 -N和TN平均去除率分别为48.30%、84.24%和42.18%;随着水力负荷的增加,COD、NH4 -N和TN平均去除率均降低,当水力负荷为0.39 m3/m2·h时,COD、NH4 -N和TN平均去除率分别为48.33%、84.81%和42.54%. 相似文献
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为缓解湖泊富营养化问题,需进一步降低入湖河流氮的含量。针对滇池流域新运粮河的低C/N水质特征,研究了冬季低温条件下的微曝气生物滤池(BAF)及固相反硝化(SPD)组合异位脱氮工艺。结果表明,BAF+SPD组合工艺启动挂膜阶段,约3周后,NH4+-N的去除率达80%以上,而反硝化细菌增殖相对缓慢,约5周后,NO3--N的去除率达80%以上;稳定运行的低温阶段,除降雨时间外,NH4+-N平均去除率达80%,出水NH4+-N浓度<1 mg/L;NO3--N平均去除率达到85%以上,出水NO3--N浓度<1 mg/L;TN平均去除率达80%以上,出水TN浓度<2 mg/L,主要水质指标达到国家地表水Ⅴ类标准。 相似文献
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采用一体化A/O移动床生物膜法工艺,以模拟生活污水研究了该工艺的除碳脱氮效果,并对一体化移动床生物膜反应器的好氧区和缺氧区各纵向断面的COD、DO、NH3-N、TN、NO-3-N和NO-2-N进行了检测,通过对缺氧区各断面的DO和TN浓度分布情况,分析了脱氮的产生过程。试验结果表明: 在水力停留时间HRT=12 h,好氧区DO保持5 mg/L左右,COD进水浓度处于250~400 mg/L时,COD的去除率均在90%以上,且出水COD均在40 mg/L以下;TN进水浓度为20~50 mg/L时,NH3-N去除率高于90%,其出水浓度可达到5 mg/L以下,脱氮效率也较高,TN去除率可达到65%~85%。COD和NH3-N的浓度分布状况表明该一体化A/O移动床生物膜反应器的流态趋于全混式。 相似文献
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采用生物接触氧化(BCO)+曝气生物滤池(BAF)组合工艺深度处理洗涤剂废水,研究了溶解氧浓度(DO)、水力停留时间(HRT)对其处理性能的影响。实验结果表明,随着DO浓度的提高,组合工艺对COD和LAS的去除率都随之增加;水力停留时间的增加有利于对COD与LAS的去除,最佳停留时间选为21.2h为宜;在BCO段DO为3.0 mg/L,HRT为20.0 h,BAF段DO为4.0 mg/L,HRT为1.2 h的运行条件下,COD与LAS的去除率分别为90.5%和94.3%,出水COD和LAS均能达到排放标准。 相似文献
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将新型CAMBR反应器(厌氧折流板反应器(ABR)与膜生物反应器(MBR)优化组合)用于处理生活污水,研究温度对该反应器处理效能的影响。实验水力停留时间7.5 h,混合液回流比设置为200%,pH值为6.5~8.5,溶解氧3 mg/L左右。控制3个温度梯度:高温(32~37℃),中温(20~25℃),低温(5~10℃),每个温度运行35 d。结果表明,在高温条件下,系统出水COD、NH4+-N、TN和TP平均浓度分别为25、0.5、12.5和0.7 mg/L。在中温条件下,系统出水COD、NH4+-N、TN和TP浓度分别30、1.2、12.5和0.4 mg/L。在低温条件下,COD和TP分别经过15 d和20 d调整适应,出水可恢复至35 mg/L和1 mg/L。由于低温(10℃以下)对硝化细菌产生强烈抑制,出水NH4+-N去除率最终稳定在35%,TN去除率为40%。低温条件下,该反应器应用于污水处理中需注意适当保温,以保证出水水质。 相似文献
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本研究基于上向流曝气生物滤池污水处理系统,研究了该工艺不同气水比、不同水力停留时间、不同滤料高度层、反冲洗强度对污染物的处理效能的影响。结果表明,气水比为4∶1、水力停留时间2 h时,BAF出水中COD、NH+4-N和SS指标达到最佳;沿程污染物去除率随着滤料层高度的增加逐渐增大,当滤料高度大于1.6 m时趋于稳定,COD、NH+4-N和SS平均去除率分别达到80%、99%和80.3%。建议曝气生物滤池的反冲洗推荐程序为:先气冲(18 L/(m2·s)),单独气洗2~3 min;再气冲(18 L/(m2·s))加水冲(5 L/(m2·s)),联合反冲洗3~5 min;最后水冲(5 L/(m2·s)),漂洗5~8 min。 相似文献
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曝气充氧和人工造流技术修复河道污染水体 总被引:5,自引:1,他引:4
基于模拟河道反应器,考察了曝气充氧及人工造流技术对污染水体的修复效果。结果表明,河道本身具有一定的自净能力,自然运行条件下对COD、TP、NH3-N和TN的去除率分别为7.44%、4.88%、5.70%和10.60%。通过对模拟河道进行曝气充氧,最佳气水比条件下对COD、TP、NH3-N和TN的去除率分别为15.33%、10.45%、6.78%和21.18%。在曝气基础上通过设置人工阻流板,对COD、TP、NH3-N和TN的去除率分别为26.82%、16.07%、9.51%和23.80%。结果初步显示,通过曝气充氧和人工造流技术的集成应用研究,对污染水体具有明显有效的修复作用。 相似文献
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The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween 80) and sodium dihexyl sulfosuccinate (Aerosol MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl(2) yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (>30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR=1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (<5%) occurring when the total trapping number exceeded 2 x 10(-5). These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple aggressive mass removal followed by enhanced bioremediation to treat chlorinated solvent source zones. 相似文献
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Torben Nielsen Anders Feilberg Mona-Lise Binderup 《Environmental science and pollution research international》1999,6(3):133-137
The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen.
In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in
1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for
buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was
caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced
many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH,
while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to
be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator,
was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with
a depletion of benzo(a)pyrene. 相似文献
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Jaana Koistinen Sirpa Herve Raija Paukku Mirja Lahtiperä Jaakko Paasivirta 《Chemosphere》1997,34(12):2553-2569
Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle. 相似文献
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Andreia Garcês Isabel Pires Paula Rodrigues 《Journal of environmental science and health. Part. B》2020,55(1):75-89
AbstractIn the last decades, the use and misuse of pesticides in the agriculture have increased, having a severe impact on ecosystems and their fauna. Although the various effects of pesticides on biodiversity have been already documented in several studies, to our knowledge no consistent overview of the impact of pesticides in vertebrates, both terrestrial and aquatic, is available. In this review, we try to present a concise compilation of the teratogenic effects of pesticides on the different classes of vertebrates – mammals, birds, reptiles, amphibians and fish. 相似文献
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P.R. Fresquez D.H. Kraig M.A. Mullen L. Naranjo Jr. 《Journal of environmental science and health. Part. B》2013,48(5):885-899
Abstract The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for 3H, 90Sr, 137Cs, totU, 238Pu, 239,240Pu, and 241Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of 90Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g‐1 [126E‐02 Bq kg‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g‐1 [518E‐02 Bq kg‐1]). The differences in 90Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y‐1 (1.0 ± 1.0 μSv y‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y‐1 (1000 μSv y‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations. 相似文献
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G T Brooks 《Journal of environmental science and health. Part. B》2013,48(5):619-621
The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9. 相似文献
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Wilkins K Nielsen KF Din SU 《Environmental science and pollution research international》2003,10(3):162-166
We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted. 相似文献
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Abstract The pH‐disappearance rate profiles were determined at ca. 25°C for 24 insecticides at 4 or 5 pH values over the range 4.5 to 8.0 in sterile phosphate buffers prepared in water‐ethanol (99: 1 v/v). Half‐lives measured at pH 8 were generally smaller than at lower pH values. Changes in half lives between pH 8.0 and 4.5 were largest (>1000x) for the aryl carbamates, carbofuran and carbaryl, the oxime carbamate, oxamyl, and the organophosphorus insecticide, trichlorfon. In contrast, half lives of phorate, terbufos, heptachlor, fensulfothion and aldicarb were affected only slightly by pH changes. Under the experimental conditions described half lives at pH8 varied from 1–2 days for trichlorfon and oxamyl to >1 year for fensulfothion and cyper‐methrin. Insecticide persistence on alumina (acid, neutral and basic), mineral soils amended with aluminum sulfate or calcium hydroxide to different pH values and four natural soils of different pH was examined. No correlation was observed between the measured pH of these solids and the rate of disappearance of selected insecticides applied to them. These observations demonstrate the difficulty of extrapolating the pH dependent disappearance behaviour observed in homogeneous solution to partially solid heterogeneous systems such as soil. 相似文献
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Blunt RE Walsh KA Ashton DK Viant MR Chipman JK 《Environmental science and pollution research international》2007,14(5):293-296
A Natural Environment Research Council (NERC) funded Knowledge Transfer (KT) workshop was held in the United Kingdom (UK)
to identify the needs and opportunities in the application of molecular biology and ‘omics’ techniques to environmental monitoring
and risk assessment. Attendees highlighted a lack of effective communication between end-users and researchers as well as
difficulties with data interpretation as reasons behind the slow uptake of molecular biology and omics techniques. A number
of promising areas in which new techniques could be implemented at a practical level in the very near future were identified,
thereby raising the profile of these recent technologies and providing vital proof of concept work. Molecular taxonomy, bacterial
source tracking and pre-screening of chemicals for potential toxicities were all viewed as areas in which omics and molecular
techniques could have immediate value, with the aim of reducing cost, increasing efficiency and providing more comprehensive
data of improved quality. 相似文献
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Ona Sakaliene Sharon K. Papiernik William C. Koskinen Kurt A. Spokas 《Journal of environmental science and health. Part. B》2013,48(6):641-647
This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine~ amitrole~ simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log Kow) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides. 相似文献