Hospital wastewater treatment coupling electrochemical coagulation (ECC) and activated sludge process (ASP)

Dual treatment of raw hospital wastewater (RHWW) is investigated by coupling electrochemical coagulation (ECC) with the activated sludge process (ASP) to achieve the goal of partial mineralization and reclaim quality water. The quality parameters of focus were chemical oxygen demand (COD), color, mixed liquor suspended solids (MLSS), total dissolved solids (TDS), chloride, total alkalinity, and fecal coliform. The initial ECC process with short hydraulic retention time (HRT) could remove 75–82% of the insoluble constituents in <60 min, while the HRT for ASP was >7–8 h. The combined ECC + ASP hybrid treatment process showed effective removal of COD, color, TDS, and fecal coliform by 98.5, 99.6, 83.1, and 97.9%, respectively, from its initial values of 4,000, 2,200, 77, and 2,400 MPN/100 mL, respectively. By coupling ECC and ASP, both the insoluble and soluble pollutants/contaminants in the RHWW were removed effectively. The ECC–ASP dual treatment offers a small energy and spatial footprint for mineralizing RHWW.