• Energy management;
  • environmental analysis;
  • environmental policy;
  • life cycle;
  • process selection;
  • sewage treatment


The environmental impact of small-scale sewage-treatment works has been evaluated using the technique of ‘life-cycle analysis’. Three sewage-treatment works with different process options were analysed to identify and quantify material use, energy use and environmental releases during construction, operation and demolition. This enabled (i) a comparison to be made between process options, and (ii) the identification of opportunities for the improvement of environmental performance. Subject to satisfactory sewage treatment and sludge disposal, the technique identified additional impacts of importance, which have implications for energy management, works design, supplier management and general environmental policy. Life-cycle analysis provides a useful insight into environmental impact and has potential for wider application within the water industry.