A review of catchment management in the new context of drinking water safety plans

By managing a catchment effectively, the range and amount of contaminants entering waters used for public water supply can be reduced, with resultant benefits for both water companies and consumers. Consequently, catchment management is increasingly being recognised as being at the heart of the water environment. An overview of current and previous catchment management initiatives is given, along with the European Landscape Convention, which could be used as a vehicle for the implementation of a national catchment management strategy. The adoption of the drinking water safety plan approach is strongly advocated by the World Health Organisation, and effective catchment management underpins this approach. Effective management of our catchments will also make a significant contribution to meeting our obligations under the Water Framework Directive, by helping to address the serious issue of diffuse pollution from agriculture.     

Sustainable reduction in the flux of microbial compliance parameters from urban and arable land use to coastal bathing waters by a wetland ecosystem produced by a marine flood defence structure

'Natural' treatment systems such as wetlands and reed beds have been proposed as sustainable means of reducing fluxes of faecal indicator organisms (FIOs) to recreational and shellfish harvesting waters. This is because FIO fluxes to coastal waters from both point (effluent) and diffuse (catchment) sources can cause non-compliance with microbiological standards for bathing and shellfish harvesting waters. The Water Framework Directive requires competent authorities in the member states to manage both point and diffuse sources of FIOs in an integrated manner to achieve compliance with 'good' water quality as defined in a series of daughter Directives. This study was undertaken to investigate the relative sources of FIOs to the popular bathing waters around Clacton, UK. In this predominantly arable (mainly cereal cropping) farming area, the principal land use predictor, explaining 76% of the variance in geometric mean presumptive Escherichia coli concentration at sub-catchment outlets during the bathing season, was the proportion of built-up (i.e. urbanised) land in each sub-catchment. This new finding contrasts with earlier studies in livestock farming regions where the proportion of improved grassland has proven to be the strongest predictor of microbial concentration. Also novel in this investigation, a flood defence wall has been built creating a wetland area which discharges every tidal cycle. The wetland produces over 97% reduction in the flux and concentrations of FIOs to the marine recreational waters. Also, FIO concentrations in water draining through the wetland to the sea were similar to concentrations measured in six UK sewage treatment plant effluents subject to secondary (biological) treatment followed by UV disinfection.     

改进消防水枪性能的实验研究

针对目前消防水枪中出现的问题，为提高水枪射流的喷射距离和灭火效果，对国产现用消防水枪提出了改进方案。改进后的水枪由整流器、自激振荡脉冲射流喷嘴和接头所组成。实验观测：射流以脉冲形式喷出，如同一连串的水弹，喷射距离也有一定程度的提高。     

探讨城市污水在线监测系统的应用

介绍了水质、水量在线监测系统的发展、应用情况以及系统所采用的在线设备和指标。详细描述了污水厂在线监测系统的结构、数据采集、传输方式及其辅助系统，指出了系统应用中出现的问题。     

小型游泳池池水消毒——臭氧消毒

本文通过臭氧消毒系统的工程实例,对其进行介绍、分析和总结,以供参考。     

Microbiological water quality in urban coastal beaches: the influence of water dynamics and optimization of the sampling strategy

In the summer 2001, the microbiological water quality of two contiguous urban coastal beaches (Porto, Portugal) was surveyed for 18 consecutive days. The sampling strategy consisted in sampling surface water in early morning, noon and afternoon. A total of 184 samples were processed at Pastoras beach, a confined area between two jetties, and Ourigo Beach more open to the ocean. At the first beach site, all samples exceeded fecal contamination above guide values (GV) and 82.6% above mandatory values (MV) set out in the EU Bathing Water Directive; whereas at Pastoras Beach, the figures were 93.5% for GV and 26.1% for MV, showing a potential health risk. The periodicity of fecal indicators in raw sewage, the tidal status and wind conditions dramatically influenced the water quality. The quality decreased in the morning regardless of tide conditions, but improved subsequently during the day, particularly during high tide and under the influence of afternoon NW winds. These dynamics are incompatible with the fortnight routine sampling according to the recommendations of the EU Bathing Water Directive, and the strategy should be revised on a beach-to-beach basis, having in mind the profile for the coastal zone.     

世方豪庭热水集中供暖系统钢制散热器工程实例

本文从实际应用角度介绍了钢制板式散热器在世方豪庭项目成功使用的经验。在热水集中供暖系统中使用自动加药控制pH值的水处理装置,加强系统的运行管理(如严格控制失水量,实施非采暖季满水湿保养),可以对钢制散热器和系统起到阻蚀阻垢的作用。     

高温工质冷凝换热试验台设计

系统介绍了高温工质冷凝换热试验台的设计方法。试验台由高温工质自然循环子系统、冷却水机械循环子系统和计算机监测控制子系统构成,试验段进出口温差及冷凝管进出口温度的测试、蒸汽锅炉充注量及液位控制、高温水箱自然作用水头的设计、冷却水流量计量水箱的设计等是试验台设计中值得重视的问题。根据误差分析结果,该试验台冷凝传热系数的相对误差为±7.19%,管内、管外的冷凝换热系数的相对误差分别为±4.95%和±8.73%。     

人工湿地污水处理技术综述

介绍了人工湿地的概念、类型及特点,同时分析了人工湿地处理污水的净化机理,并对人工湿地污水处理技术国内外研究现状进行了综述,同时指出该技术对于节省资金、保护水环境以及进行有效的生态恢复具有十分重要的意义.     

唐河倒虹吸管身段施工中的关键技术

介绍唐河倒虹吸管身混凝土施工过程中的模板技术、钢筋连接新技术、止水带安装、施工缝留置及混凝土浇筑方法。