Membrane-coupled methanogenic and facultative bioreactor in wastewater treatment

This paper evaluates the feasibility of a membrane-coupled methanogenic and facultative bioreactor (MCMFB) system in treating the wastewater from the liquid crystal display (LCD)-related industry. The treatment unit is comprised of an anaerobic (methanogenic) and an aerobic reactor. The hollow fiber membrane module (0.036 mum) was submerged in the aerobic reactor for solids/liquid separation. An average 80% COD removal was achieved in the anaerobic reactor when the volumetric loading reached 7.2 kg COD/m³ per day. The effluent of the anaerobic treatment was fed into the aerobic-membrane tank to treat the residual COD. The mixed liquor suspended solids of the aerobic tank was 7000 mg/L with an average F/M of 0.14 g COD/g SS per day, and the removal efficiency of the aerobic tank was 90% in average. The transmembrane pressure and the flux of the membrane remained stable during the entire period of the 140-day operation without any backwash or chemical wash, indicating the applicability of the MCMFB system on treating the targeted wastewater.