Upgrading of sewage treatment plant by sustainable and cost-effective separate treatment of industrial wastewater

摘要

This paper summarises the physicochemical and microbiological quality of water from a rainwaternharvesting (RWH) system in a UK-based office building. 7 microbiological and 34 physicochemicalnparameters were analysed during an 8 month period. Physicochemically, harvested rainwaternquality posed little health risk; most parameters showed concentrations below widely usednguideline levels for drinking water. However, RWH system components (e.g. fittings and downnpipes) appear to be affected soft water corrosion, resulting in high concentrations of some metalsn(copper, zinc and aluminium). This suggests the material selection of such fittings should benconsidered keeping in view the hardness of rainwater of an area. Microbiologically,nCryptosporidium, Salmonella and Legionella were not present in the samples analysed. However,nfaecal coliform counts were high at the beginning of the study, but did decrease over time in weakncorrelation with increasing pH. Enterococcus faecalis displayed counts consistently above UKnrainwater harvesting standards. Inappropriate roof and rainwater good design, as well as materialnselection appear to be responsible for the reduced microbial quality, as they promotedncontributions from avian sources and inhibited cleaning activities. Building and RWH systemndesigns require greater consideration of local factors, which are critical for optimising harvestednrainwater quality, to prevent both the development of contaminated sediments and health impacts.