Hyperhaline Municipal Wastewater Treatment of a Processing Zone by Pilot-Scale A/O MBR Part Ⅰ: Characteristics of Mixture Liquor and Organics Removal

摘要

An integrated anoxic/aerobic membrane bio-reactor (A/O MBR) was designed to treat hyperhaline municipal wastewater from a processing zone of Tianjin, China. The characteristics of mixture liquor in MBR and removal performance of CODCr were studied, and the contribution of membrane and microbes to organic pollutant removal was evaluated and discussed. The experimental results show that MLSS and MLVSS had similar fluctuation and the ratio of MLVSS/MLSS was around 0.4. Settling characteristics of the sludge in aerobic zone was nice at the first more than one month operation and was deteriorated significantly after two month operation. The relative low MLVSS/MLSS ratio was due to the accumulation of large quantity of inert substance and inorganic matters since only once sludge discharge in the four-month investigation period and relative high inorganic substance in influent. The deterioration of sludge settling was caused by the accumulation of the SMP and EPS from microbe and high value of MLSS. The CODCr removal efficiency of the integrated A/O MBR system was 80%-95% during the four-month investigation period. Very good organic removal was mainly contributed to the microbial biodegradation. To ensure high-quality and stable effluent water, the contribution of membrane interception to activated sludge and insoluble organic matters cannot be neglected, especially under an unsatisfied biodegradation.