Screening of organic contaminants in urban snow

Snowmelt is known to cause peak concentrations of pollutants, which may adversely affect receiving water quality. High concentrations of metals and suspended solids in snow have been reported, whereas studies on organic pollutants are rare. This study aims at investigating the occurrence of anthropogenic organic compounds in urban snow in Gothenburg (Sweden). The most frequently detected organic pollutants in the collected snow samples were polycyclic aromatic hydrocarbons (PAHs), high molecular-weight phthalates, 4-nonylphenol and 4-t-octylphenol. Brominated flame retardants and chlorinated paraffins were only sporadically detected. In several snow samples, the concentrations of specific PAHs, alkylphenols and phthalates were higher than reported stormwater concentrations and European water quality standards. Pollutant source identification and sustainable management of snow are important instruments for the mitigation of organic contaminants in the urban environment.     

深圳河湾水系生态需水的污水资源化

以深圳河湾水系为例,探讨以污水资源化再生水满足城市水系生态需水的方法。该方法统一考虑河流的水量水质需求,计算不同截污率和补水水质条件下河流的生态需水量;根据生态用水的供需平衡情况,确定污水资源化规模与水质要求。在此基础上,设计污水资源化的处理工艺以及再生水厂等的分布;并通过数学模型预测补水方案对水环境改善的效果。本研究为面向城市水系生态补水的污水资源化工程规划提供了科学的方法。     

武汉市湖泊中重金属污染状况

鉴于重金属元素的生理毒害作用,选择武汉市区、近郊、远郊六个代表性湖泊水体研究其水、沉积物、鱼样品中主要毒害重金属元素Hg,Cd,As,Pb,Cu,Cr,Ni,Zn的污染状况。采用原子荧光测试样品中Hg含量,其他元素用ICP-MS测试。结果表明:市区湖泊水、沉积物及鱼中重金属含量多数明显高于郊区湖泊,其中水及沉积物中重金属含量与研究区相应环境背景值对比有显著富集,但湖泊水中重金属含量大多可满足GB 3838—2002《地表水环境质量标准》Ⅲ类水质要求,鱼中重金属含量也可满足相应GB 2736—1994《淡水鱼卫生标准》。市区湖泊与郊区湖泊样品重金属污染程度对比而言,市区湖泊明显表现出受到一定人为污染影响。     

Bioassessment of wet-weather pollution impacts on fine sediments in urban waters by benthic indices and the sediment quality triad.

Benthic invertebrate assessments can be used to gauge the impact of urban wet-weather flows in receiving waters. Experiences from Cemagref in France have shown that standardized benthic indices (e.g. Oligochaete Index of Sediment Bioindication - IOBS) can be used to reliably determine the ecological status of urban streams and can be incorporated into the new European Water Framework Directive. The Canadian studies on streams and stormwater ponds using chemical analyses, benthic toxicity testing and benthic invertebrate community structure (i.e. the sediment quality triad) comparisons have shown that toxicity was more likely to occur in ponds at sites with higher concentrations of heavy metals and heavier polycyclic aromatic hydrocarbons, and at greater water depths, where fine sediments from urban runoff accumulated. A more comprehensive evaluation of wet-weather flow impacts could be obtained by combining approaches from both countries.     

Loading and lake circulation structures recurrent patterns of water quality on the Toronto – Mississauga waterfront of Lake Ontario

Urban centers line western Lake Ontario where urban rivers, wastewater treatment plants and stormwater load nutrients, major ions and suspended solids to the nearshore. In 2018, nearshore water quality and associated physical conditions bordering the cities of Toronto and Mississauga were assessed as a benchmark for future effects of urban growth and municipal infrastructure projects to improve water quality. Conductivity and UV-fluorescence were used as water quality surrogates and mapped over blocks of shoreline stratified by distance offshore. Patterns in UV-fluorescence aligned with loading points, and generally higher levels near the shoreline, were correlated with concentrations of nutrients, major ions and suspended solids. Water quality was more land-impacted over the shoreline from the Credit River to Humber Bay contrasting with the more lake-like conditions from Toronto Eastern Beaches to the Rouge River. Within Toronto Harbour, cross-harbour gradients in water quality varied with weather-related changes in river and storm water loading. Mixing areas at wastewater treatment plant outfalls and tributary mouths, frequently shaped by alongshore lake circulation, resulted in a mosaic of water quality over the shoreline. Area-wide elevation of chloride and conductivity, and poorer water quality in late spring, was linked to heightened river discharge. Thermal stratification affected how discharges were distributed in the water column, but measurements at the lake surface reflected the strongest overall land-effects on water quality. The patterns of temporal-spatial variability identified within geographically-defined areas of shoreline can be used as past footprints in future monitoring to detect change.     

UV/H2O2 degradation of endocrine-disrupting chemicals in water evaluated via toxicity assays.

Due to rising concern regarding the presence of endocrine-disrupting chemicals (EDCs) in surface water and groundwater throughout the United States, Asia and Europe, treatment of these chemicals in drinking water and wastewater to protect human health and the environment is an area of great interest. Many conventional treatment schemes are relatively ineffective in removing EDCs from water and wastewater. This is concerning because these chemicals are biologically active at very low concentrations and effects of mixtures are relatively unknown. 17-alpha-oestradiol (E2) and 17-beta-ethinyl-oestradiol (EE2), suspected EDCs, were degraded significantly by the UV/H2O2 AOP. The UV/H2O2 processes using either low or medium pressure lamps were degraded EDCs by between 80 and 99.3% at a 15 ppm H2O2 concentration and a UV dose of 1,000 mJ/cm2. Significantly greater removal was noted when the removal was based on total oestrogenic activity using a yeast oestrogen screen (YES) assay. These data indicated that a dose of less than 200 mJ/cm2 completely removed oestrogenic activity in lab water. Values for natural waters were slightly higher. A steady state model was developed to determine EDC destruction efficiency in waters of differing quality. The model effectively predicted destruction in water, where concentrations of all scavenging species were known. Based on these results it was concluded than complete destruction of oestrogenic activity was possible under practical advanced oxidation conditions for a variety of water qualities.     

Saline sewage treatment and source separation of urine for more sustainable urban water management

While energy consumption and its associated carbon emission should be minimized in wastewater treatment, it has a much lower priority than human and environmental health, which are both closely related to efficient water quality management. So conservation of surface water quality and quantity are more important for sustainable development than green house gas (GHG) emissions per se. In this paper, two urban water management strategies to conserve fresh water quality and quantity are considered: (1) source separation of urine for improved water quality and (2) saline (e.g. sea) water toilet flushing for reduced fresh water consumption in coastal and mining cities. The former holds promise for simpler and shorter sludge age activated sludge wastewater treatment plants (no nitrification and denitrification), nutrient (Mg, K, P) recovery and improved effluent quality (reduced endocrine disruptor and environmental oestrogen concentrations) and the latter for significantly reduced fresh water consumption, sludge production and oxygen demand (through using anaerobic bioprocesses) and hence energy consumption. Combining source separation of urine and saline water toilet flushing can reduce sewer crown corrosion and reduce effluent P concentrations. To realize the advantages of these two approaches will require significant urban water management changes in that both need dual (fresh and saline) water distribution and (yellow and grey/brown) wastewater collection systems. While considerable work is still required to evaluate these new approaches and quantify their advantages and disadvantages, it would appear that the investment for dual water distribution and wastewater collection systems may be worth making to unlock their benefits for more sustainable urban development.     

The Evaluation of Kurtboğazı Dam (Ankara,Turkey) from Hydro-Geochemical and Environmental Aspects

Kurtboğazı Dam is one of the most significant sources of drinking water sources for Ankara City. In this study, hydro-geochemical properties and pollution sources of surface waters feeding into the dam are determined. In addition, important environmental problems such as squatter’s houses and wastewater discharges within protection zones of watershed of the dam are defined and appropriate precautions are discussed. The long-term trend (1998–2007) in water quality results of the dam and the surface waters in the Kurtboğazı watershed were studied, utilizing data provided by General Directorate of State Water Works (DSI). The results indicate that waters in the watershed can be classified as waters with calcium-bicarbonate. Due to the drought conditions experienced in recent years, the concentrations of the organic materials and nitrogen and phosphorus compounds in the surface waters have increased dramatically since 2005. It is thought that wastewaters discharged by the settlements within the watershed (especially Pazar Township) are responsible for these increases. Preventing wastewater discharges from the squatter’s houses and agricultural activities on the absolute and the proximate zones of the watershed and the constructing of a sewerage and treatment plant are the first challenges for the protection of the watersheds.     

城市生活用水多样化趋势与水资源的可持续利用

通过对杭州市生活用水需求变化与用途多样化趋势的调查研究,用量化分析方法寻找与之相关的因素,并以此预测城市用水趋势。针对目前城市生活用水量日益增加、其中低质杂用水的比例较大的情况,从水环境综合治理角度,探讨城市水资源合理利用的最佳系统方式,并提出污水资源化、充分利用雨水、建立新型给排水系统等建议。     

Presence and risk assessment of pharmaceuticals in surface water and drinking water

Trace amounts of pharmaceuticals have been detected in surface waters in the nano- to microgram per liter range, and in drinking water in the nanogram/L range. The environmental risks of pharmaceuticals in surface waters have been evaluated and generally found to be low if the wastewater is treated before release to the environment. The human health risks of trace amounts of pharmaceuticals in drinking water have however not been evaluated in any great depth. Preliminary screening level assessments suggest risk to be low--but the public and decision-makers are concerned and would like the matter investigated more thoroughly, especially with regards to mixture effects, chronic long-term effects and sensitive sub-populations. The World Health Organization is currently evaluating the need for credible health based guidance associated with low concentrations of pharmaceuticals in drinking water. The aim of this paper is to summarize the state-of-the-science and the ongoing international debate on the topic.     

Frequency analysis of river water quality using integrated urban wastewater models

In recent years integrated models have been developed to simulate the entire urban wastewater system, including urban drainage systems, wastewater treatment plants, and receiving waterbodies. This paper uses such an integrated urban wastewater model to analyze the frequency of receiving water quality in an urban wastewater system with the aim of assessing the overall system performance during rainfall events. The receiving water quality is represented by two indicators: event mean dissolved oxygen (DO) concentration and event mean ammonium concentration. The compliance probability of the water quality indicators satisfying a specific threshold is used to represent the system performance, and is derived using the rainfall events from a series of 10 years' rainfall data. A strong correlation between the depth of each rainfall event and the associated volume of combined sewer overflow (CSO) discharges is revealed for the case study catchment, while there is a low correlation between the intensity/duration of the rainfall event and the volume of the CSO discharges. The frequency analysis results obtained suggest that the event mean DO and ammonium concentrations have very different characteristics in terms of compliance probabilities at two discharging points for CSO and wastewater treatment plant effluent, respectively. In general, the simulation results provide an understanding of the performance of the integrated urban wastewater system and can provide useful information to support water quality management.     

河流水质模型(RWQM1)介绍及实例分析

以河流水质为目标对城市污水系统进行集成管理,是改善河流水质、保护生态环境的有效途径。介绍了国际水协会河流水质1号模型(RWQM1),该模型采用与标准活性污泥模型类似的描述方式,用化学需氧量作为有机物度量描述有机物与营养物,选择表征碳、氢、氧、氮、磷循环的水质成分和模型状态变量,描述河流中好氧与缺氧条件下物质的循环变化过程。该模型可直接与活性污泥模型相连接,用于集成城市污水处理系统的设计规划与监视控制。     

苏州市吴中区河道水环境现状及治理对策浅析

苏州市吴中区地表水环境问题对苏州城市经济社会发展、太湖水质改善及人居生活质量有较大影响。沿河工业企业废污水大量排放是造成水环境质量下降的主要原因,必须加强水环境治理,建立节水减排机制,统筹经济社会、城市发展、工业企业、人居环境等建设规划;必须保护修复水生态水环境,加强河道排污管理,工业退城进区等有效措施。应用近年来吴中区河道水质监测资料,分析评价水环境恶化原因,提出治理对策与措施,以修复水生态,改善水环境。     

An integrated approach for solving urban water and wastewater crises in the Arabian Gulf States.

Various environmental and economic aspects of urban water and wastewater crises in a number of the Arabian Gulf States are discussed. An integrated approach, which considers simultaneously the problems of urban waters (shortage of water supply and problems associated with urban drainage) and those in connection with wastewater (i.e. environmental impact) is proposed. The feasible link between the main factors affecting these problems and the anticipated results encourage the implementation of the proposed approach. The conclusions suggest immediate municipal legislation.     

Ecologically based standards for nutrients in streams and ditches in The Netherlands

General and specific water quality standards were formulated on a national scale in The Netherlands in the eighties of this century. A general environmental quality was defined as the minimum acceptable water quality level for all inland waters. For this quality level, standards for total phosphorus and total nitrogen were derived from measurements in shallow lakes sensitive to eutrophication for this quality level. No standards were developed for specific environmental quality.In this study we tested whether single nutrient standards are sufficient to guarantee the minimum quality level in streams and ditches. We also investigated whether specific environmental quality requires specific standards. We, therefore, analyzed data collected by regional waterboards in The Netherlands.The results show that nutrient standards for the general quality are not sufficient to guarantee the minimum quality for all water types. They do not provide appropriate protection for aquatic life. More specific standards should be set to protect and preserve the full biodiversity of ditches and streams.Setting a single standard for general environmental quality and one for specific environmental quality for all types of water is not defendable. Different types of water have different aquatic communities and different nutrient levels. It is therefore recommended that water type dependent standards should be developed. In this study, standards for both general and specific environmental quality in respect to nutrients are proposed for six stream types and for six ditch types.     

Phenol wastewater remediation: advanced oxidation processes coupled to a biological treatment.

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. Wet air oxidation and Fenton process were tested batch wise, while catalytic wet air oxidation and H2O2-promoted catalytic wet air oxidation processes were studied in a trickle bed reactor, the last two using over activated carbon as catalyst. Effluent characterisation was made by means of substrate conversion (using high liquid performance chromatography), chemical oxygen demand and total organic carbon. Biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) were obtained from respirometric tests using activated sludge from an urban biological wastewater treatment plant (WWTP). The main goal was to find the proper conditions in terms of biodegradability enhancement, so that these phenolic effluents could be successfully treated in an urban biological WWTP. Results show promising research ways for the development of efficient coupled processes for the treatment of wastewater containing toxic or biologically non-degradable compounds.     

Membrane Process Design for the Reduction of Wastewater Color of the Mazandaran Pulp-Paper Industry, Iran

The aim of this study is evaluate the use of membrane bioreactor for wastewater treatment Mazandaran pulp and paper Industry. The qualification of wastewater is case study and Characteristics of this industry wastewater were determined by different experiments such as: COD, BOD, Color, densitometry, viscometry and TG/DTA analyzer. Also, the color creating agents in the investigated wastewater was characterized. Then In this study, flux, retention, and permeate quality of various Nanofiltration and low-pressure reverse osmosis membranes were investigated at two temperatures and by using a low shear (DSS Labstak M20®) and a high shear (CR250/2) filter. The overall aim was to study the suitability of Nanofiltration in purification of the discharge water from external activated sludge processes in the pulp and paper industry for reuse in the paper manufacturing process and to compare the results to Nanofiltration of paper machine process waters. The discharge waters were nanofiltered at a higher flux than paper machine process waters. The permeate was almost free of color and organic compounds but contained significantly more inorganic compounds than the permeate from the filtration of process waters. To successfully remove monovalent anions and inorganic carbon from the discharge water a low-pressure reverse osmosis membrane such as the TFC ULP membrane is needed. With that membrane the permeate flux is lower than for Nanofiltration membranes but the permeate quality is significantly better when considering inorganic ions such as sodium, chloride, nitrate and inorganic carbon (bicarbonate). The permeate flux was two times higher in the high shear filter than in the low shear filter but the retentions were significantly lower. The result of this study: decrease pollutants parameter in Tajan Rivers that is effluent because attention to surface water quality has limited in Iran.     

Interaction of oxygen concentration and retention of pollutants in vertical flow constructed wetlands for CSO treatment.

The EU Water Framework Directive (WFD) calls for a good quality of all water bodies. Retention soil filters (RSF) have been developed to treat discharges from combined sewers systems. RSF have proved over the past 15 years to be the most effective measure to meet the EU WFD standards, especially for small or particularly sensitive receiving waters, which require an enhanced reduction of emissions from combined sewer overflows (CSOs). The paper presents results from laboratory-scale experiments, in which the oxygen measurement in the filter plays a main role. The results show remarkable differences in oxygen concentrations in different filter depths. The highest oxygen consumption takes place in the upper part of the filter. In the lower part the re-aeration of sewage from the soil air dominates. This indicates that the biological activity is limited to the upper part of the filter. The availability of oxygen in the filter is a sign for degradation of wastewater compounds (ammonium, COD) under certain conditions and already takes place during the filter operation. The removal of ammonium especially cannot be strictly divided into phases of sorption during the loading and oxidation during the dry period any more.     

上海污水排放口水域水质和底质分析

本文分析了上海竹园和白龙港两处污水排放口附近水域的水质和底质现状,并与长江口大水域进行比较,研究了城市污水排放对长江口局部水域造成的污染和对水域富营养化的影响。研究结果表明,城市污水排放口附近局部水域氮、磷污染严重,其它污染物影响较小。长江口大水域氮、磷、铜、铅和化学需氧量浓度均较高,水污染严重,并有逐年上升趋势。分析认为城市污水排放贡献了大量的氮、磷,但未对重金属污染造成明显影响。排放口水域和长江口大水域均处于富营养化状态,分别为"磷限制潜在性富营养"和"磷中等限制潜在性富营养"。为控制赤潮的发生,建议上海城市污水排放前进行脱氮除磷处理。     

Riparian wetlands for enhancing the self-purification capacity of streams.

Best Management Practices (BMPs) are increasingly used to restore river water quality but design guidance is limited. An alternative approach to remediating diffuse pollution loads is to identify the most polluting high flows from pollutographs and hydrographs and spill these flows into riparian treatment wetlands for treatment before drainage back into the watercourse. The approach is demonstrated for two contrasting catchments in Scotland impacted by diffuse pollution. The Caw Burn receives industrial estate drainage with high suspended solids, hydrocarbons, BOD and ammoniacal-nitrogen concentrations. Applying the proposed design criteria demonstrated that the existing retrofit BMP system at the site is undersized (4950 m2) compared to the required wetland area (11,800 m2), but accommodating the additional area is likely to be expensive. The second case-study is Brighouse Bay where bathing waters are impacted by faecal indicator organisms derived primarily from livestock runoff. In this catchment the riparian wetland area required to retain runoff so that E. coli bacteria would die-off to concentrations below bathing water standards was estimated to be 3-6ha (0.5-1% of catchment area). Further refinement and testing of the design approach is required, including consideration of other factors such as vegetation type, ownership and maintenance, to develop a more holistic approach to river restoration.