Rainwater harvesting and technology: to investigate the application of rainwater reuse in makeup water of fresh water cooling tower system in Hong Kong

Abstract

Fresh water cooling tower system in Hong Kong consumes potable water as its makeup source. However in reality, it is possible to use non-potable water like the harvested rainwater as a part of makeup source for the conservation of potable water because rainfall usually comes at April to September while the cooling tower system has higher water consumption from May to October in H.K. environment. Besides, the analysis of statistics revealed that rainwater harvesting can contribute up to 15% of makeup source prior to the maximization of "Ratio of rainwater retention tank volume to catchment area (V/A)". In accordance with the guidelines - "Quality Water Recognition Scheme for Buildings" of WSD and "Minimum Monitoring Frequency of Makeup Water for Cooling Tower System" of EMSD, we put up with a feasible rainwater treatment process to meet the water quality standard.