Trends and Problems of Wastewater Reuse Systems in Buildings

To solve the shortage of available water source, the national government and local authorities have introduced the policy to make use of alternative water sources such as reuse of wastewater and utilization of rainwater in big buildings. This paper deals with the background, the details of the practice of wastewater reuse systems in buildings, and survey results on the performance of recycling systems installed in big buildings. The investigation suggests that most of reclamation plants perform very good in quality but not good in quantity. There has never been any serious claim from users nor any hygiene trouble in these several years. But the full capacity of plants was not usually utilized as designed. The very small demand at weekends and holidays creates operational problems of biological treatment plants and raises cost of reclaimed water. Individual building wastewater reuse is not efficient enough as expected to solve the shortage of water resources. However, it still remains to be a very important means to deal with urban problems. It will lessen excess loading on existing sanitary sewers and interceptors, and will reduce pollutants discharged from a sewage treatment plant.