Effect of organic loading rate and retention time on pollutant reduction in batch process for graywater treatment

Abstract

Graywater (GW) is the term given to all used water discharged from a house, except for toilet water. Among the different sources, laundry and kitchen sink are the main contributors to the total GW load of organic carbon and suspended solids; these sources can also be called dark GW, whereas bathtub and handbasins are the less polluted sources of GW known as light GW. The main aim of this study was to evaluate the effect of organic loading rate (OLR) (0.27, 0.49, and 0.82 COD kg/m3/d) and retention time (RT) (8, 16, and 24 h) on sand filters. The performance of coarse and fine sand filter was monitored by monitoring the reduction in biochemical oxygen demand (BOD), chemical oxygen demand (COD), oil and grease (O&G), and turbidity. The experimental results showed that increase in OLR and RT increase the removal efficiency. The maximum removal efficiency was observed in BOD was 78%, COD was 77%, O&G was 75%, and turbidity was 81% at 24 h RT and OLR 0.82 kg/m3/d.