Efficiency of submerged ceramic flat membrane bioreactor in the treatment of coal chemical wastewater

Abstract

Coal chemical wastewater inhibits the development of the modern coal chemical industry. This study used a submerged ceramic flat membrane bioreactor to treat coal chemical wastewater. By combining the characteristics of high flux and high strength of ceramic flat membrane with the characteristics of high sludge concentration of Membrane Bio-Reactor (MBR). The treatment effect of ceramic flat membrane bioreactor on coal chemical wastewater and related influencing factors were studied. The Chemical Oxygen Demand (COD) concentration, ammonia nitrogen concentration, total phenol concentration, and turbidity of coal chemical wastewater could be reduced to below 31.4 mg/L, 3.03 mg/L, 3.76 mg/L, and 0.4 NTU. The ceramic flat membrane bioreactor achieved the optimal removal effect on pollutants when Hydraulic Retention Time (HRT) was 21 h, Dissolved Oxygen (DO) concentration was 3.2–4.0 mg/L and pH was 7.1–7.5. Among them, the total phenol removal ratio reached the maximum value of 95.31 %, and the COD removal ratio remained at 93 % ∼ 94 %, ammonia nitrogen removal ratio was stable at 95 % ∼ 97 %. The microorganisms in the mixture and membrane mainly were aerobic bacteria, and the content of organic-degrading bacteria, nitrifying and denitrifying bacteria was high. The addition of a membrane module not only prevented the loss of activated sludge in the reactor but also kept a high sludge concentration. Meanwhile, the addition of a membrane module also improves the biodiversity and stability of sludge treatment system.