Derivation of numerical values for the World Health Organization guidelines for recreational waters

In April 2001, draft ‘Guidelines’ for safe recreational water environments were developed at a World Health Organization (WHO) expert consultation. Later the same month, these were presented and discussed at the ‘Green Week’ in Brussels alongside the on-going revision of the European Union Bathing Water Directive 76/160/EEC. The WHO Guidelines cover general aspects of recreational water management as well as define water quality criteria for various hazards. For faecal pollution, these include faecal indicator organism concentrations and an assessment of vulnerability to faecal contamination. Central to the approach set out in the WHO Guidelines are: (i) the concept of beach profiling to produce a ‘sanitary inspection category’ which implies a priori hazard assessment as a core management tool and (ii) the prediction of poor water quality to assist in real time risk assessment and public health protection. These management approaches reflect a harmonized approach towards the assessment and management of risk for water-related infectious disease being applied by WHO. Numerical microbiological criteria for intestinal enterococci are proposed in the new Guidelines. These were developed using a novel approach to disease burden assessment, which has been applied to both recreational waters and urban air quality. This paper explains the scientific rationale and mathematical basis of the new approach, which is not presented in the WHO Guidelines for recreational waters.     

Pollution loads in urban runoff and sanitary wastewater

While more attention has been paid in recent years to urban point source pollution control through the establishment of wastewater treatment plants in many developing countries, no considerable planning nor any serious measures have been taken to control urban non-point source pollution (urban stormwater runoff). The present study is a screening analysis to investigate the pollution loads in urban runoff compared to point source loads as a first prerequisite for planning and management of receiving water quality. To compare pollutant loads from point and non-point urban sources, the pollutant load is expressed as the weight of pollutant per hectare area per year (kg/ha.year). Unit loads were estimated in stormwater runoff, raw sanitary wastewater and secondary treatment effluents in Isfahan, Iran. Results indicate that the annual pollution load in urban runoff is lower than the annual pollution load in sanitary wastewater in areas with low precipitation but it is higher in areas with high precipitation. Two options, namely, advanced treatment (in lieu of secondary treatment) of sanitary wastewater and urban runoff quality control systems (such as detention ponds) were investigated as controlling systems for pollution discharges into receiving waters. The results revealed that for Isfahan, as a low precipitation urban area, advanced treatment is a more suitable option, but for high precipitation urban areas, urban surface runoff quality control installations were more effective for suspended solids and oxygen-demanding matter controls, and that advanced treatment is the more effective option for nutrient control.     

底部开放的半封闭卫生填埋设计思想

全封闭卫生填埋是目前流行的城市固体废弃物最终处置方法之一。但是由于技术和经济方面的原因,该方法在实际应用中存在不少问题。笔者提出底部开放的半封闭卫生填埋设计思想,阐述了发展这种填埋方式的合理性和必要性,分析了填埋场渗滤液经由土壤和周围水体的衰减机制,对渗滤液总量控制技术和尚待研究的其它问题进行了讨论。     

Risk factors contributing to microbiological contamination of shallow groundwater in Kampala,Uganda

A study of water quality variation in shallow protected springs in Kampala was undertaken over a 12-month period to assess the causes of microbiological contamination. The microbiological quality of water was assessed using thermotolerant coliforms and faecal streptococci. Sanitary inspections and hazard assessments were undertaken to identify faecal sources (hazards), contaminant pathways and contributory factors. Data were collected on rainfall and population as additional factors potentially exerting an influence on microbiological quality. Initial analysis of the data showed a significant relationship between median level of contamination and rainfall, in particular to short-term rainfall events. Total sanitary risk score showed a significant relationship with median level of contamination, but population density may be a confounding factor. The raw microbiological data were transformed into five water quality targets: <1 and < or =10 cfu 100ml(-1) for faecal streptococci; and <1, < or =10 and < or=50 cfu 100 ml(-1) for thermotolerant coliforms. The presence of individual risk factors as well as variables for rainfall and population density were analysed with respect to failure to meet these water quality targets using contingency tables. Logistic regression models were developed for each of the five water quality targets. The analysis strongly suggested that there is rapid recharge of the springs after rainfall and this leads to microbiological contamination. On-site sanitation was less important than other sources of faecal matter, which was consistent with a low sanitation coverage in the study area. The study suggested that improving sanitary completion and local environmental hygiene was more important than controlling on-site sanitation in improving the quality of these springs.     

浅谈客房卫生洁具安装的技术要点

分析了宾馆、饭店及招待所的客房卫生间的卫生洁具不能保证长期正常使用的原因。就如何确保卫生洁具的安装质量进行了详细的论述，并提出一些具体的方法、措施及施工中应注意的问题。     

浅谈新加坡组屋给排水系统

组屋为大部分新加坡人的住所,由政府出资建造,使用年限为99年,其内部给排水系统设计形式及施工工艺与我国有诸多差异.将新加坡组屋给排水系统的构成作了初步介绍,并将部分施工环节与我国作了对比,指出其优点所在.其中户内给水铜管的安装应用、户内排水承插套管预埋、共用水封设计有其自身的优越性,值得我国借鉴;雨水系统采用明设沟渠排水的方式,应对暴雨疏水迅速,可为各国学习参照.     

Fecal indicator bacteria and Salmonella in ponds managed as bird habitat, San Francisco Bay, California, USA

Throughout the world, coastal resource managers are encouraging the restoration of previously modified coastal habitats back into wetlands and managed ponds for their ecosystem value. Because many coastal wetlands are adjacent to urban centers and waters used for human recreation, it is important to understand how wildlife can affect water quality. We measured fecal indicator bacteria (FIB) concentrations, presence/absence of Salmonella, bird abundance, and physico-chemical parameters in two coastal, managed ponds and adjacent sloughs for 4 weeks during the summer and winter in 2006. We characterized the microbial water quality in these waters relative to state water-quality standards and examined the relationship between FIB, bird abundance, and physico-chemical parameters. A box model approach was utilized to determine the net source or sink of FIB in the ponds during the study periods. FIB concentrations often exceeded state standards, particularly in the summer, and microbial water quality in the sloughs was generally lower than in ponds during both seasons. Specifically, the inflow of water from the sloughs to the ponds during the summer, more so than waterfowl use, appeared to increase the FIB concentrations in the ponds. The box model results suggested that the ponds served as net wetland sources and sinks for FIB, and high bird abundances in the winter likely contributed to net winter source terms for two of the three FIB in both ponds. Eight serovars of the human pathogen Salmonella were isolated from slough and pond waters, although the source of the pathogen to these wetlands was not identified. Thus, it appeared that factors other than bird abundance were most important in modulating FIB concentrations in these ponds.     

A new method to assess the influence of migration from polymeric materials on the biostability of drinking water

After having produced drinking water of high quality it is of vital interest to distribute the water without compromising its quality neither by recontamination nor by microbial regrowth. To minimize regrowth, the strategy of distributing biostable water is followed in several European countries. This implies on one hand the production of water that has a low level of growth-supporting nutrients, in particular organic carbon compounds, and, on the other hand, using materials for storage/distribution that have a low biofilm formation potential and from which only low amounts of total organic carbon (TOC) leach into the water phase. Currently, the approval of materials in contact with drinking water relies on two tests, a migration test and a biofilm formation test. Here we describe an extended migration testing procedure that allows to obtain information not only on the amount of chemical compounds but also on the amount of growth-supporting compounds leaching into the water. In short, the test developed combines several migration cycles and subsequent measurement of the TOC with a novel, fast and reliable test method for determining the assimilable organic carbon (AOC) in the migration waters. AOC gives an indication on the growth-supporting properties of the material. Thus, an initial characterisation of a material with respect to its suitability for usage in contact with drinking water can be performed in a single assay. Results obtained with the new assay for a number of materials typically used in drinking water and sanitary installations are reported.     

Microbiological studies on the quality of urban stormwater runoff in Southern Ontario, Canada

The microbiological quality of urban stormwater runoffs was investigated at three different locations in Southern Ontario, Canada. Microbial densities in these waters were similar to those found in dilute raw wastewaters and, therefore, represent a potential health hazard. The recovery of pathogenic bacteria (Pseudomonas aeruginosa and salmonellae) further substantiated the existence of health hazards. There appeared to be little relationship between the duration, intensity and amount of rainfall and the occurrence of peak microbial populations. As a result, no typical pattern of time-related distribution of indicator and pathogenic bacteria could be established in this investigation. This suggests that “initial flushing” has minimal effect on the microbiological quality of an individual storm event. Furthermore, the results indicate the seriousness of urban stormwater runoffs as a major factor in nonpoint source pollution of receiving waters and that it would be illogical to disinfect specific portions of these runoffs for removing health hazards as there was no predictable pattern of pathogen occurrence.     

市政道路和雨污水管道施工质量控制及预防

结合工程实例，从沟槽开挖、管道安装两方面对雨、污管道的施工质量预防及控制进行了阐述，并对土基及基层施工质量的预防及控制措施进行了论述，以保证市政道路、雨污水管道的施工质量。     

Organic indicators of groundwater pollution by a sanitary landfill

The organic composition of leachate from the Barcelona sanitary landfill is described. According to the low degree of stabilization of the disposed garbage the acid fraction accounts for 80–90% of the total organic extract. More than 50 individual organic components have been identified, indicating catabolic degradation of lipids (e.g. C₄–C₁₁ carboxylic acids), proteins (e.g. indole derivatives) and lignins (e.g. p-hydroxyphenyl derivatives) or simply compounds originally present in the refuse that have been washed out by percolating waters (nicotine, caffeine, phthalates).To obtain a monitoring system for the groundwater pollution originated by this landfill leachate, an analytical method is proposed based on the GC-ECD fingerprinting of groundwater acidic extracts after derivatization with PFB bromide. The chromatogram contains carboxylic and phenolic components and the profiles exhibited by waters from several test wells in the downstream edge of the landfill were indicative of the suspected leachate pollution.     

市政雨、污水管道合槽施工技术的应用

结合某工程实例介绍了市政雨、污水管道合槽施工技术的应用,并与先开挖污水管线、再开挖雨水管线的传统做法进行了比较,对施工进度、质量、成本等指标进行综合比较后表明,在适当条件下,采用合槽施工技术更具合理性.此外,详述了合槽施工的适用条件和施工难点,为工程施工提供了借鉴.     

Speciation as an Aid to Understanding the Chemistry of Water Treatment

The deliberate formation of solid precipitates is a treatment process commonly used to remove undesirable ions from solution. Where the chemistry of the water to be treated is complex, a knowledge of the chemical species present, and their concentrations, can be an effective tool in evaluating the effectiveness of the treatment process and in optimizing reagent dosage and operator control. The use of chemical equilibrium speciation computer programs offers a relatively rapid method to determine the type and concentrations of chemical species present at equilibrium. Some sulphate-rich waters of significance to South Africa have been speciated using the MINTEQA2 computer program. The effects of treating these waters with barium carbonate have been evaluated. The computer predictions of treated water quality have been experimentally verified.     

Mechanism of degradation of the quality of natural water in the Lakes Region of the Ethiopian rift valley

The natural waters of the Lakes Region in the Main Ethiopian Rift (MER) show serious problems of chemical quality. The high content of fluoride reaches 300 mgl(-1) and affects the health of the population who live in this area. Furthermore, the alkaline and sodic characteristics (8 2(Ca + Mg)]. which results from the weathering and dissolution of the volcanic rocks. The predictive qualities of the model AQUA were tested in the context of this region. A simulation of the concentration of the waters by evaporation has shown chemical variations relatively similar to those obtained with field data which include the minor chemical elements such as the fluoride or the dissolved silica. For field data, enrichment is more variable and may represent localised conditions of mineralization. This model is then used to study a method of defluoridation by supplying these waters with calcium in the form of gypsum. This method also allows the reduction of the alkalinizing and sodifying characteristics of the waters without reaching the fluoride standard concentration accepted for drinking waters. For drinking purpose, waters of the Ethiopian rift should undergo another method of defluoridation.     

模拟自然循环的生态水环境设计与实施初探

文章阐述了生态水环境设计与实施的必要性,提出＂生活污水——人工净化处理——绿化——土壤渗滤——回归水体——回用＂的技术路线。以某高校校区为例,进行了模拟自然循环方式再利用污水的可行性分析。探讨了土壤渗滤管道的敷设方法以及存在的问题,对土壤渗滤出水水质与水量调蓄方面做了初步阐述,并对比分析了土壤过滤处理后出水水质、城市杂用水和景观用水的区别,得出经过土壤渗滤用水安全更有保障的结论,并给出预期成果的适用范围。     

Biological technology of the treatment of leachate from sanitary landfills

A laboratory investigation was conducted into low cost treatment of leachate from sanitary landfills. At room temperatures (20–25°C), anaerobic treatment was shown to remove over 95% of the soluble BOD and essentially all the iron, while over 90% of the nitrogen was converted to free ammonia. Two complete schemes of leachate treatment are suggested for pilot plant evaluation. Each has primary steps of anaerobic processing with disposal by spray irrigation or municipal sewer, followed by ammonia stripping and aerobic polishing if discharge to surface waters is required.     

生物接触氧化法在住宅小区中水工程中的应用

介绍了某住宅小区采用生物接触氧化法处理小区生活废水的原理，进行了水量平衡分析，比较了接触氧化法处理中水和其他方法处理中水的特点。通过经济效益、水质分析，表明接触氧化法在住宅小区中水工程应用方面是成功的，指出了该工艺的优缺点并提出改进意见。     

Pathogenic or potentially pathogenic bacteria as contaminants of fresh water from different sources in Araraquara, Brazil

The microbiological quality of various fresh waters in the Araraquara region, state of São Paulo, Brazil was investigated. Ninety-nine water samples were taken from rivers, reservoirs, artesian and non-artesian wells, springs and tap waters, and these waters were analysed using: plate counts of heterotrophic microorganisms (per 1 ml); Most Probable Number (MPN) of fecal coliforms and E. coli (per 100 ml); tests for presence of Salmonella, Shigella, Yersinia, the E. coli pathogens of classes EPEC, ETEC and EIEC and Mycobacterium, Shigella, Yersinia and enteroinvasive E. coli (EIEC) were not isolated. The other types of microorganisms were isolated in varying proportions. We conclude that the waters investigated represent a potential microbiological health risk.     

谈管道安装工程中的渗漏问题

从管道连接、材料质量、穿墙（板）施工、卫生设备安装、水压试验等方面进行分析，通过全面研究管道安装工程渗漏的原因，制定出相应的渗漏预防措施，进而提出了在管道安装中实施有效的工程质量控制方法。     

人造木板卫生质量概况

通过对徐州市建筑装修市场人造木板甲醛释放量检测结果的分析,了解了人造木板卫生质量概况,并进一步了解由此带来的室内环境污染问题,同时提出了相应的控制措施,以提高室内环境质量。