ABSTRACT
Water scarcity is a huge problem in the under-developed and developing countries around the world, and consequently, rainwater can be an essential water source for meeting fundamental human needs. However, these nations have paid less attention to the efficiency of conventional rainwater treatments to improve the population's health. The impact of the first flush technique is particularly investigated in this chapter, and the microbial reduction resulting from its use was assessed from five different investigated roofs. Four roofs were constructed for the purpose of this study while the fifth roof was from an actual residential building. In this study, the microbial parameters (i.e., total coliform and E. coli) and the physical parameters (i.e., total suspended solids and turbidity) of the collected rainwater were studied. In every first flush experiment, a minimum reduction of around 40% from the initial pollutant load was observed. In addition, this study discovered that, as compared to other materials, corrugated galvanised roofing provided roof-harvested rainwater (RHRW) with the best microbiological quality. Although the first flush method has been evidenced here to increase the quality of RHRW, it is advised that household water treatment techniques (HHTTs) be implemented as well, especially if the collected rainwater is to be consumed.
