On zero water discharge solutions in the process industry

This paper presents a mathematical programming approach to analyze the feasibility of zero liquid discharge option in different industries. Mathematical programming methodologies are applied to four industrial cases—a tricresyl phosphate plant, an ethyl chloride plant, a paper mill and a refinery. In each case study various end of pipe and regeneration configurations using different treatment technologies are explored to determine the possibility of zero liquid discharge and its economical feasibility. The results show that the relationship between the cost of regeneration and the cost of freshwater as well as the discharge concentration of the treatment is the determining factor for the feasibility of zero liquid discharge.     

Investigating the sources of the mutagenic activity found in a river using the Salmonella assay and different water extraction procedures

In the routine São Paulo state (Brazil) surface water quality-monitoring program, which includes the Salmonella microsome mutagenicity assay as one of its parameters, a river where water is taken and treated for drinking water purposes has repeatedly shown mutagenic activity. A textile dyeing facility employing azo-type dyes was the only identifiable source of mutagenic compounds. We extracted the river and drinking water samples with XAD4 at neutral and acidic pH and with blue rayon, which selectively adsorbs polycyclic compounds. We tested the industrial effluent, raw, and treated water and sediment samples with YG1041 and YG1042 and compared the results with the TA98 and TA100 strains. The elevated mutagenicity detected with YG-strains suggested that nitroaromatics and/or aromatic amines were causing the mutagenicity detected in the samples analyzed. Positive responses for the blue rayon extracts indicated that mutagenic polycyclic compounds were present in the water samples analyzed. The mutagen or mixture of mutagens present in the effluent and water samples cause mainly frameshift mutations and are positive with and without metabolic activation. The Salmonella assay combined with different extraction procedures proved to be very useful in the identification of the origin of the pollution and in the identification of the classes of chemical compounds causing the mutagenic activity in the river analyzed.     

流动注射荧光猝灭法测定环境水样中痕量磷

在硫酸溶液中，P(Ⅴ)与钼酸盐、钒酸盐生成磷钼钒杂多酸，使罗丹明6G荧光猝灭，据此建立了测定痕量磷的流动注射荧光猝灭方法。方法的测定范围为2～90μg／L,进样频率为35样/h。采用本法测定环境水样中痕量磷，结果令人满意。     

里杜湖富营养化综合评价及预测

根据里杜湖水库的水质监测及水文资料，选择评分法结合生物优势种评价法以及“源－效应”预测模型对里杜湖水库水质的营养状态进行综合评价及预测。结果表明：里杜湖水库水质已轻度富营养化，并有逐年加重的趋势。旨在正确评价和预测里杜湖水库营养状态，并为同类水库的营养状态评价及预测提供参考和借鉴，从而为水库水质管理及富营养化的控制提供科学依据。     

西安地区旅游景点水体卫生细菌学调查及保护对策

以粪大肠菌和异养细菌总数做指标，对西安地区旅游景点水体的卫生细菌学状况进行了调查。结果表明，西安市区内旅游景点的人工湖、天然湖等大都受到不同程度的污染，而离市区较远、海拔较高的旅游景点则污染较轻。     

Modelling the responses of the Lagoon of Venice ecosystem to variations in physical forcings

A Finite Element Ecological Model for the Lagoon of Venice (VELFEEM) has been used to test the responses of the Lagoon of Venice ecosystem to variations in physical conditions.The model is obtained by coupling a finite element hydrodynamic model, that computes the velocity fields of water, an energetic model to compute the water temperature fields, and an ecological model that simulates the dynamic of phytoplankton, zooplankton, nutrients (ammonia, nitrate and phosphate) organic detritus (organic nitrogen, organic phosphorous and CBOD) and dissolved oxygen.The transport model is a two-dimensional barotropic finite element model which allows for a better resolution of the lagoon morphology.The ecological model has been developed by starting from the ecological module EUTRO of WASP (Water Analysis Simulation System released by US EPA), and by adapting it to the peculiarity of the Lagoon of Venice.A reference condition has been identified by running a 1-year simulation under climatologic condition. Then, the sensitivity to physical forcing (tide and wind) and to the input of macronutrients has been investigated, by comparing model predictions of spatial and temporal evolution of major state variables and of an aggregate index of Water Quality Trophic Index (TRIX).     

Further studies on the influence of zeolite type A on metal transfer in the activated sludge process

Investigations were carried out to determine the effect of zeolite type A on metal removal by activated sludge using laboratory activated sludge simulations. They were operated at constant aerator sludge age and settler surface loading. Different concentrations of raw zeolite and zeolite extracted from washing powder (0, 15, 30, 60, 120 mgl^?1) were introduced into the simulations. The zeolite was added at two degrees of calcium exchanged for sodium, 25 and 75% of the maximum exchange capacity. Metals were added at concentrations typical of mixed domestic-industrial waste waters. The results show that there was no adverse effect on metal removal by the laboratory activated sludge simulations in the presence of zeolite type A.     

Management strategy for acidic deposition in Western and Northern Canada

The governments of British Columbia, Alberta, Saskatchewan, Manitoba, Northwest Territories, and Canada held joint consultations in 1980 to review the available information on acid rain from Western and Northern Canada. It was concluded that acid rain might become a problem in the future and, hence, a research, monitoring, and management strategy for acidic deposition was needed. An overview of the joint governments' management strategy, organization of research and monitoring programs, and accomplishments to date are discussed in this article.The authors are members of the Technical Committee for the Long Range Transport of Atmospheric Pollutants (LRTAP)/Acid Deposition in Western and Northern Canada, and represent Alberta and British Columbia, respectively.     

鄱阳湖区氮磷污染物分布、转移和削减特征

根据入湖污染负荷监测、调查资料和不同水文条件下流场-水质同步监测资料,应用数理统计方法,研究了鄱阳湖氮磷营养物质分布、转移和削减特征。研究结果显示:(1)总磷、总氮是影响鄱阳湖水环境质量的主要污染物,入湖污染负荷与入湖径流水量紧密正相关。(2)鄱阳湖换水周期短,水流更换频繁,氮磷污染物在湖区不会充分混合;氮磷超标水域随着水体流动,逐步向下游转移、扩散;湖水位处于消落状态,通江水道部分水域氮磷浓度超标。(3)湖相状态水环境比河相好,湖相状态一般不会出现大面积的总氮和总磷同时超标。(4)鄱阳湖水环境勉强维持Ⅲ类标准,如果出现损害环境的人类活动,脆弱的水环境将会恶化。针对这些特征提出了保护鄱阳湖"一湖清水"的对策建议。     

Organic pollutants in snow of urban and rural Russia and Finland

To check the effect of possible deposition of organic contaminants in northern regions of the Earth due to atmospheric transport snow samples were collected in early March in 6 places in Russia and 4 in Finland including arctic territories. GC‐MS was used as an analytical tool to identify and quantify individual organic compounds belonging to the various classes. As a result more than 250 compounds were detected. The possible presence of more than 100 other priority pollutants from the US EPA list was also screened.