The Application Of MABR Technology In The Ecological Restoration Of Polluted Urban River

Urban River is one of the essential elements for the survival and development of city, which plays a significant role in the economic development and ecological protection of the city and the surrounding areas. Due to the economic development and population expansion, the amount of wastewater was beyond the self-purification capacity of Urban River,which caused the environment deterioration and ecological imbalance. Therefore, the improvement of water quality and environment is of great urgency environmental restoration becomes a major subject of building ecological.Membrane aerated biofilm reactor(MABR) is a new kind of wastewater treatment, gas separation membrane is employed to be the carrier and oxygen supplier of biofilm, in order to remove chemical oxygen demand(COD), ammonia nitrogen and other pollutants, and achieve the purpose of water purification. In this study,MABR is first used in Urban River restoration.A novel continuous flow MABR process was designed, the long running experiment was carried out to study the effect of aeration pressure flow velocity on COD, ammonia nitrogen and total nitrogen(TN) removal, the purification capacity of MABR for River was evaluated. It was found that MABR has obvious effect on COD and ammonia nitrogen removal.The effluent quality met the surface water environmental quality standard. However, the TN removal is difficult to meet the standard by single stage MABR. Moreover, suspended solids(SS) content has great influences on MABR. Therefore, the pre-treatment should be added to decrease SS before MABR process.Take two-stage MABR as main processing unit, a wastewater treatment system for polluted River combined with hydrolytic acidification was constructed. The long running pilot experiment was implemented. The system was operated 40 days at the optimal operating condition(at the temperature of 19°C, pH of 7.5, reflux ratio of200%, hydraulic residence time of 15h). It is indicated that MABR remove COD,ammonia nitrogen, TN removal and SS in polluted River efficiently, the effluent quality met the surface water environmental quality standard V. Some indicators met the surface water environmental quality standard III.The quality of Huayuan Landscape River was evaluated to be eutrophication and worse than the surface water environmental quality standard V. According to the characteristics of Huayuan Landscape River, water grass type MABR membrane module and floating MABR system were designed, bioremediation was carried out. It is reflected that MABR bioremediation system improved the self-purification capacity of Huayuan Landscape River efficiently by 5 months water quality monitoring. The TN removal met the surface water environmental quality standard V; all the otherindicators met the surface water environmental quality standard IV. The algal bloom can’t be observed in the entire operating process.This thesis research fora novel efficient urban river water ecological restoration technology development has laid a good foundation.