Performance evaluation of a field-scale anaerobic baffled reactor as an economic and sustainable solution for domestic wastewater treatment

The present study explored the efficiency of a four-chambered anaerobic baffled reactor (ABR) as a cost-effective and sustainable method of organic pollutant and pathogen removal from domestic wastewater, under a range of environmental conditions. An ABR with a circular additional filter at the outlet pipe was constructed to treat wastewater from a residential colony of 108 households with an average inflow of 110 m3/day and a nominal hydraulic retention time (HRT) of 20 h. Analysis of the chemical oxygen demand (COD), total nitrogen, sulfate and phosphate load, and total coliform removal for 2 years of operation, 2015 and 2017, showed a COD of 46, sulfate load of 28, phosphate load of 51 and total nitrogen of 28 for 2015, compared to a COD of 48, sulfate load of 44, phosphate load of 58 and total nitrogen of 31 for 2017. The lack of a significant effect of sludge removal suggested a stable process. The overall efficiency of the ABR increased in the summer, including for pathogen removal, which was significantly higher during the summer months of both years. Overall, the ABR was found to be able to consistently treat primary wastewater, although tertiary effluent treatment was still required before water reuse or final discharge