Low-cost ceramic filter bioreactor for treatment and reuse of residential septic tank effluent: A decentralized approach for small communities

Abstract

Membrane biological reactors (MBRs) have recently become widely accepted as an advanced technology for treating domestic wastewater for improved water recovery, reuse, and recycling. The present study investigated the application of a low-cost ceramic filter bioreactor (CFBR) to treat septic tank effluent for smaller communities in Saudi Arabia (KSA). Filter fouling behavior, pollutant removal, and effluent quality were assessed under varying flux (0.2, 0.4, and 0.65 m/d) and aeration on/off cycle (60 min/60 min, 40 min/80 min, 30 min/90 min, 24 h/24 h) conditions. Operating CFBR at a flux value of 0.4 m/d ensured moderate fouling propensity, reasonable flux decline, and a higher volume of treated effluent. In the continuous aeration mode experiments, CFBR demonstrated the removal of various pollutants. Except for NO3N, CFBR effectively reduced all other pollutants of concern (BOD, COD, TSS, NH3N) in the effluent to acceptable levels meeting the water quality standards for unrestricted irrigation set by the KSA. An enhanced NO3N removal at the 24 h/24 h on/off cycle, indicating the effectiveness of cyclic aeration for promoting both nitrification/denitrification in the CFBR, with sufficient removal of other pollutants, is an original finding of the present study. Simple and cost-effective operations, high-quality effluent, and reduced energy consumption with shorter aeration duration promote the sustainability of the CFBR system for wastewater reclamation and reuse in small communities and rural settlements.