城市回用污水中病毒对人体健康风险的评价

目的评价城市回用污水中病毒对人体健康的风险。方法于2002年5～11月对西安北石桥污水净化中心二级处理出水和常规再生工艺处理后的回用水中的总大肠杆菌和粪大肠菌进行检测并进行数据的正态分布假设检验。同时观察了液氯消毒对污水中大肠杆菌的去除效果。利用评价饮用水中病原微生物感染概率的beta-Possion模型和MonteCarlo模拟方法对城市回用污水中病毒对人体健康的风险进行评价。结果二级处理出水和回用水中粪大肠菌群浓度呈对数正态分布。污水中大肠杆菌去除率在7mg/L和15mg/L液氯接触20min时分别为4log和5log。城市回用污水用于城市绿化和灌溉农田时,水中病毒对人体健康的年风险均值分别为1.21×10-6和4.31×10-8,且其最高风险均低于美国EPA地表水处理规范(SWTR)规定的生活饮用水可接受年风险(10-4),即使回用于对人体暴露量较大的景观娱乐用水(如游泳),其年风险值<10-4的概率也在90%以上。结论城市回用污水用于城市绿化和灌溉农用时,水中病毒对人体健康风险很小。     

铜川市粪便处理厂工艺设计

介绍了陕西省铜川市粪便处理厂采用厌氧消化-沉淀-SBR工艺,对粪便的固形物和污水进行处理,经过厌氧消化池后上清液采用SBR法处理,污水出水水质达到国家二级排放标准,固形物用以堆肥.并对经营成本和投资进行了估算.     

水体中病毒的三种浓缩方法及其效果比较

目的 比较水体中病毒的三种浓缩方法,评价各方法的浓缩效果,为水体中病毒浓缩方法的选择提供依据.方法 将不同浓度的指示病毒(脊髓灰质炎病毒1型PV1)加入经高压灭菌处理后的污水处理厂二级出水中,采用钙离子法、牛肉汤洗膜法和载阳电荷滤料法对水样分别进行浓缩,采用逆转录-PCR技术检测灵敏度,观察指示病毒的某一特征基因片段P...     

污水处理去除蛔虫卵效果的评价

本文对高碑店污水处理厂的原污水和经一级、二级处理的出水进行定期检测,结果表明原污水通过一级、二级处理能去除绝大多数的蛔虫卵。     

基于GRNN的污水出水水质预测模型

利用广义回归神经网络(GRNN),建立基于GRNN的污水出水水质预测模型.选取污水DO、ORP、MISS、进水COD等参数作为输入,出水COD作为输出,进行训练仿真.结果表明:该模型可以应用于污水出水水质的预测,且相比传统BP网络具有设计简单,学习速度快,预测精度高的优势.     

人工湿地系统在我国中小城镇污水处理中的应用

分析了我国中小城镇水污染现状及形成原因,介绍了人工湿地系统作用机理及其特点,并与传统污水处理工艺进行了比较,得出应用人工湿地系统处理污水具有效率高,投资和运转费用低,处理效果好,易于操作管理,生态和社会效益好等结论.     

重庆市农村三格化粪池后粪水处理方法的现场研究

目的研究农村三格化粪池排出粪水的处理方法。方法在重庆市九龙坡区西彭镇宝华村选择10户农家,在其卫生厕所三格化粪池后新建第四格小型人工湿地处理池,并在第二格或第三格加挂半软性填料,3～6个月后检测第三格池粪水和第四格小型人工湿地处理池出水口水质,按GB18918-2002中《城镇污水处理厂污染物排放标准》规定指标和要求测定处理前后的水质,计算达标率和清除率,比较处理前的后效果。结果10户农家第四格小型人工湿地处理池出水口水质检测指标达到国家污水二级排放标准户数分别为CODcr8户;氨氮6户;总磷9户;总氮1户;总悬浮物7户;色度6户;pH值10户;粪大肠菌群值10户。各检测指标的清除率(%)分别为:CODcr57.0%～90.6%;氨氮74.7%～91.6%;总磷68.3%～96.9%;总氮35.2%～96.9%;总悬浮物43.0%～80.0%;色度4.9%～90.6%。结论新建第四格小型人工湿地处理池对三格化粪池后的粪水处理效果好。     

人工湿地生态系统在城市污水回用中的可行性

分析了我国城市污水回用的方式及存在的问题,阐述了人工湿地生态系统的机理及在污水回用中具有的高效率、低投资、低运转费、低维持技术、处理量灵活、低能耗、处理效果好等优点,说明人工湿地生态系统在城市污水回用中是可行的。     

卫生防护与三废处理

饮用水过氧化氢预氧化生产性试验；高锰酸钾法降低自来水锰含量的技术运用；O3-沸石-GAC处理常州运河微污染水源水研究；应用悬浮填料预处理微污染原水的影响因素探讨；生物滤沟处理景观水体试验研究；景观水体污染处理工艺研究及工程应用；污水处理中的紫外浅消毒技术；纳滤在城市污水处理中的应用；医院污水的净化处理研究；基因工程菌强化芳香化合物的处理工艺；微氧生物吸附-好氧生物氧化联合工艺处理污水的试验研究；活性污泥2号模型用于城市污水处理厂脱氮除磷改造的研究；污水渗滤土地处理系统中的堵塞问题；有机沸石对水中BTEX及铬酸根离子的吸附；改性聚丙烯腈纤维对铅镉汞离子的吸附性能研究；有机膨润土吸附水中有机物的盐效应及其机理。     

污水处理传统工艺与新工艺出水中有机提取物的雌激素样作用比较

目的评价污水处理厂传统处理工艺和新技术处理工艺出水中有机提取物的雌激素样活性,比较两种处理工艺对微量有机污染物的去除效果。方法采用树脂吸附固相萃取富集水样中的微量有机污染物,利用重组基因酵母试验和小鼠子宫增重实验检测水样中有机提取物的雌激素样活性大小。结果重组基因酵母检测中,在原水样中微量有机污染物浓缩1000倍条件下,新技术出水有机提取物处理的酵母表现出β-半乳糖苷酶活性,而三级出水、二级出水和进水都为500倍,相同条件下的β-半乳糖苷酶活性,新技术出水组三级出水组二级出水组进水组。小鼠子宫增重实验中,仅进水有机提取物油溶液原液组和阴性对照组之间具有显著性差异(P0.05),其他各水样组之间皆无显著性差异。结论郑州市城市污水经处理后雌激素样活性显著下降,但仍对环境具有潜在危害;新技术对污水中微量有机污染物的去除效果明显好于传统技术。     

人工湿地在小区中水回用中的应用与前景展望

我国水资源极为缺乏,中水回用是解决水资源短缺的重要途径之一。在小区中水回用技术中,人工湿地处理工艺因其集中水处理和水景绿化功能于一体,而备受关注。对目前人工湿地在小区中水回用中的应用现状和存在的问题进行了分析,并对其前景进行了展望。     

Morphological Response of Typha domingensis to an Industrial Effluent Containing Heavy Metals in a Constructed Wetland

Typha domingensis had become the dominant species after 2 years of operation of a wetland constructed for metallurgical effluent treatment. Therefore, the main purpose of this study was to investigate its ability to tolerate the effluent and to maintain the contaminant removal efficiency of the constructed wetland. Plant, sediment, and water at the inlet and outlet of the constructed wetland and in two natural wetlands were sampled. Metal concentration (Cr, Ni, and Zn) and total phosphorus were significantly higher in tissues of plants growing at the inlet in comparison with those from the outlet and natural wetlands. Even though the chlorophyll concentration was sensitive to effluent toxicity, biomass and plant height at the inlet and outlet were significantly higher than those in the natural wetlands. The highest root and stele cross-sectional areas, number of vessels, and biomass registered in inlet plants promoted the uptake, transport, and accumulation of contaminants in tissues. The modifications recorded accounted for the adaptability of T. domingensis to the conditions prevailing in the constructed wetland, which allowed this plant to become the dominant species and enabled the wetland to maintain a high contaminant retention capacity.     

Using constructed wetlands to treat biochemical oxygen demand and ammonia associated with a refinery effluent

This study evaluated the effectiveness of constructed wetlands for tertiary treatment of a petroleum refinery effluent. Specific performance objectives were to decrease 5-day biochemical oxygen demand (BOD(5)) and ammonia by at least 50% and to reduce toxicity associated with this effluent. Two bench-scale wetlands (replicates) were constructed in a greenhouse to provide tertiary treatment of effluent samples shipped from the refinery to the study site. Integrated wetland features included Typha latifolia Linnaeus planted in low organic (0.2%), sandy sediment, 48-h nominal hydraulic retention time, and 15-cm overlying water depth. Targeted constituents and aqueous toxicity were monitored in wetland inflows and outflows for 3 months. Following a 2 to 3-week stabilization period, effective and consistent removal of BOD(5) and ammonia (as NH(3)-N) from the effluent was observed. Average BOD(5) removal was 80%, while NH(3)-N decreased by an average of 95%. Survival of Pimephales promelas Rafinesque and Ceriodaphnia dubia Richard (7-day, static, renewal exposures) increased by more than 50% and 20%, respectively. Reproduction of C. dubia increased from zero in undiluted wetland inflow to 50% of controls in undiluted wetland outflow. This study demonstrated the potential for constructed wetlands to decrease BOD(5), ammonia, and toxicity in this refinery effluent.     

Triclosan in a north Texas wastewater treatment plant and the influent and effluent of an experimental constructed wetland

The antimicrobial triclosan was analyzed in unfiltered samples from influent, effluent, and receiving stream and before and after a pilot-scale constructed wetland at a North Texas municipal wastewater treatment plant. Triclosan concentrations were reduced by 97 to 99% by the activated sludge treatment plant. Effluent concentrations were further reduced by passage through the constructed wetland, but receiving stream concentrations were not statistically significantly different from effluent concentrations. Effluent concentrations of triclosan were seasonal with highest concentrations occurring during the summer months. The effluent-dominated receiving stream maximum concentrations during summer months were below reported algal no-observed-effect concentrations based on biomass and growth rate but exceeded concentrations reported to cause shifts in algal community structure.     

The Effects of Tannery Wastewater on the Development of Different Plant Species and Chromium Accumulation in <Emphasis Type="Italic">Phragmites australis</Emphasis>

Toxicity tests were performed to assess the effect of tannery wastewater with different treatment levels on two wetland plants, Phragmites australis and Typha latifolia, which are frequently used in constructed wetlands (CWs) for water treatment, and thus deepen the knowledge on their capacity to withstand the application of industrial wastewater. Trifolium pratense, a plant generally used as an indicator in toxicity tests, was included as a control. End points measured were germination percentage, shoot length, root elongation, and biomass growth of the plants. When tannery effluent, with a low treatment level, was supplied to the wetland plants germination occurred even at effluent concentrations of 100%, whereas germination of T. pratense was completely inhibited, almost invariably, at effluent concentration of 50%. Higher germination levels were achieved when the plants were exposed to effluent originating from the outlet of constructed wetland pilot units, allowing germination of all tested plants, indicating a significant decrease in its toxicity level. Experiments conducted with the same plants using different growing substrata as the germination matrix, namely expanded clay aggregates (Filtralite MR 3-8 and Filtralite NR 3-8) and two types of sand (fine gravel and standard sand) have shown that higher germination levels were achieved in standard sand and that P. australis was the plant species showing higher germination in all cases, reinforcing the robustness of this plant to environmental stress. The phytoextraction potential of P. australis, was evaluated by subjecting the plant to tannery wastewater supplemented with 50 and 150 mg Cr/L. After 6 weeks of exposure, levels up to 4825, 883, and 627 mg Cr/kg were found in the rhizome, shoot, and leaves, respectively, although phytotoxic signs in the plant were evident. This plant might not be considered a chromium hyperacumulator, but the potential to extract and accumulate this metal on its rhizomes is high.     

Assessment of the estrogenicity and toxicity of a domestic wastewater effluent flowing through a constructed wetland system using biomarkers in male fathead minnows (Pimephales promelas rafinesque, 1820)

The toxicity and estrogenicity of a final treated municipal effluent was examined while flowing through a constructed wetland in north-central Texas, USA. Fish data were collected, and a baseline wetland characterization was performed to assess wetland treatment potential for these effluent properties. Vitellogenin (VTG), gonadosomatic index (GSI), hepatosomatic index (HSI), and secondary sexual characteristics were biomarkers used in fish models to assess aqueous estrogenicity. Biological indicators used to assess overall fish health included hematocrit and condition factor. Estrogenic nature of final sewage treatment works effluent was screened, concurrent with a three-week fish exposure, via gas chromatography/mass spectrometry for target estrogenic compounds, including 17beta-estradiol, ethynylestradiol, bisphenol A, nonylphenolic compounds, phthalates, and DDT. The VTG in Pimephales promelas was measured after exposure at four sites in a treatment wetland and was significantly elevated (p < 0.0001) in fish exposed at the inflow site. The GSIs were significantly less (alpha = 0.001) at the inflow site. At wetland sites closest to the inflow, secondary sexual characteristics, tubercle numbers, and fatpad thickness were less (alpha = 0.0001) than in laboratory controls. The HSIs and density of male breeding stripes were not significantly different from those of laboratory controls. However, elevated HSIs were found at the inflow site. Hematocrit and condition factors were both less (alpha = 0.001) in effluent-exposed fish at wetland sites closer to the inflow than in control fish or fish further downstream.     

Assessment of Toxicity Reduction in Wastewater Effluent Flowing Through a Treatment Wetland Using Pimephales promelas, Ceriodaphnia dubia, and Vibrio fischeri

Effluent toxicity is regularly assessed with Ceriodaphnia dubia short-term chronic and Vibrio fischeri toxicity tests. Condition factor and hemotocrit of fish have recently been used to assess fish health following exposure to xenoestrogens in complex municipal effluents. To assess the ability of a treatment wetland to reduce or remove toxicity of a municipal effluent, we compared C. dubia and V. fischeri bioassays to Pimephales promelas responses in situ. Final whole effluent was diverted to a constructed wetland and effluent samples were taken daily from four sites, at incremental distances from the inflow, for a 3-week study. Overlapping 7-day C. dubia tests and V. fischeri assays were conducted with samples from each wetland site concurrent with a 3-week fish exposure. C. dubia survival and fecundity were significantly (< 0.0001) reduced at the inflow, but steadily improved with distance from the inflow. Fish condition and hematocrit were lower (α < 0.05) at wetland sites closer to the inflow than other wetland sites and laboratory controls. However, effluent toxicity was not detected by V. fischeri bioassays. Our findings indicate that 7-day C. dubia bioassays were most sensitive to effluent toxicity and suggest that other bioassays should be used concurrent with V. fischeri assays for municipal effluent toxicity testing. Received: 20 November 2000/Accepted: 18 June 2001     

The Evaluation of Metal Retention by a Constructed Wetland Using the Pulmonate Gastropod Helisoma trivolvis (Say)

Constructed wetlands are built because they can act as sinks for many pollutants, thereby protecting the water quality of downstream ecosystems. The treatment performance is generally assessed using mass balance calculations. Along with the mass balance approach, we compared the metal content of populations of a common pond snail (Helisoma trivolvis Say) collected upstream and downstream of a 3-year-old constructed wetland. Snails were collected in early May, June, and August 1998. At the same time, water samples for particulate and dissolved metals were taken every 3 days for the duration of the experiment. Overall, the wetland retained most dissolved metals, including Fe, Mn, Cu, Zn, Ni, and Pb, but released dissolved As. However, the wetland released particulate Fe and Mn. With the exception of Zn, the metal concentrations of the downstream snails were on average higher than those measured in the upstream population. The higher metal content of downstream snails was likely related to the significant export of particulate metals by the wetland, despite the overall retention of dissolved metals. This study points to the need for biological as well as chemical monitoring to determine the treatment efficiency and toxicological risk associated with constructed wetlands. Received: 28 February 2000/Accepted: 6 September 2000     

Improvement of water quality using constructed wetland systems

Constructed wetlands are among the recently proven efficient technologies for wastewater treatment. Compared with conventional treatment systems, constructed wetlands are low in cost, easily operated and maintained, and have a strong potential for application in developing countries, particularly by small rural communities. Nevertheless, the use of constructed wetlands for the improvement of drinking water quality (such as the purification of river water for drinking purposes) is still uncommon. Treatment technologies that use natural processes and/or passive components continue to be of interest to many segments of society for a wide variety of applications. This article summarizes information on the current methods used for water treatment using constructed wetland systems and presents several case studies.