Evaluation of Swirl-Flo™ Clarifier and UV/H2O2 Process for Domestic Wastewater Treatment

Abstract

Pilot scale investigations were conducted to evaluate the efficacy of a novel process comprising of Swirl-Flo™ Clarifier (SFC) and Ultraviolet light/Hydrogen Peroxide (UV/H2O2) reactor for treatment of domestic wastewater. Overall Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD) removal of over 82 % and 90 %, respectively was achieved in the plant. TSS removal in SFC was influenced by feed flow rate. TSS removal efficiency of about 45–50 % was achieved in SFC at flow rate of about 5.5–6.0 m3 hr−1 equivalent to overflow rate of 3.1–3.4 m3 m−2 hr−1. This compared favorably against an overflow rate of up to 1.0 m3 m−2 hr−1 obtainable in gravity settling units. COD removal in SFC was about 37–42 %, while that in UV Reactor was 18–23 % at H2O2 dosing of 800–900 ppm. Further polishing of the treated effluent by sand filter and activated carbon adsorption column yielded the effluent quality satisfactory for use as make up water in cooling towers for central air-conditioning plants. The treated effluent quality was consistent and showed little variation compared to the variation in influent wastewater characteristics.