Evaluation and start-up of an electro-Fenton-sequencing batch reactor for dairy wastewater treatment

Abstract This study examined the performance of an integrated wastewater (WW) treatment system, namely an electro-Fenton (EF)-sequencing batch reactor (SBR), for dairy industry WW. The EF process was used as the first stage of the SBR. It degrades bio-refractory compounds via advanced oxidation processes, thereby resulting in the formation of simple biodegradable intermediates. Several factors, including the hydraulic retention time (HRT), sludge volume index (SVI), and sludge retention time (SRT) of the EFSBR, were optimized. The effectiveness was studied for 1 y laboratory-scale experiments under stable conditions (HRT of 10 h, SRT of 15 d, mixed liquor suspended solids concentration of 3500 mg/L, and SVI of 89), which revealed 99% chemical oxygen demand, 97% total nitrogen, and 95% total phosphorus removal. Thus, the developed system is economically feasible and superior to other conventional biological treatment systems.