Decentralized light greywater treatment using aerobic digestion and hydrogen peroxide disinfection for non-potable reuse

Implementation of decentralized greywater treatment systems can potentially solve freshwater scarcity issue as greywater is generated in large amounts, and reuse of treated greywater could reduce the demand of freshwater. Nevertheless, greywater treatment systems are sophisticated, involving many units of process equipment. Hence, there is a need to develop greywater treatment systems that can be easily operated, maintained, low cost and does not compromise treated effluent quality. An aerobic digestion unit integrated with a hydrogen peroxide disinfection unit was evaluated in this study for the purpose of greywater treatment to the standard for non-potable usage. This system was successful in removing 88 and 68 of total suspended solids and chemical oxygen demand respectively, with optimal operation settings determined to be 5 h of hydraulic retention time and an organic loading rate of 2.16 gCOD/Lday. Disinfection with hydrogen peroxide at concentration of 1 mL/L removed approximately log CFU/100 mL of bacteria and all bacteria can be eradicated after 1 day of storage. The system evaluated in this study was found to be simpler in comparison to other treatment processes used. Though further optimization will be required maximize the treatment efficiency of this system, it has the potential for implementation in small communities due to minimal microbial activity after storage and relatively small area required for treatment.