Research On Simultaneous Phosphorus And Nitrogen Removal By Aerobic Granular Sludge In Single SBR System

Eutrophication is a global problem, in which blooms of cyanobacteria and eukaryotic algae occur as a consequence of the breakdown of community homeostasis from continued pollution of oligotrophic aquatic bodies with nutrients like nitrogen (N) and phosphorus (P) at levels which exceed growth-limiting concentrations for these photosynthetic organisms and it has induced serious deterioration to the quality of water environment. Phosphorus and nitrogen removal from wastewater is an effective approach for prevention of eutrophication in closed water systems. With the development of water pollution control both internationally and domestically, it has become a hotspot to do the research on how to control the water bodies eutrophication caused by nitrogen and phosphorus, and how to remove efficiently the nitrogen and phosphorus as well as how to develop a special technics used for nitrogen and phosphorus removal, which are suitable to the situation of our country, economically and effectively.Based on the latest research findings on aerobic granular sludge and biological nitrogen and phosphorus removal in both domestic and abroad, aerobic granular sludge had been cultivated with the method of decreasing sludge sedimentation time gradually to produce selective pressure by using normal activated sludge as inoculating sludge in this paper. After successfully cultivating aerobic granular sludge, the parameters affectiong nitrogen and phosphorus removal were studied through adapting the operational conditions of SBR. And then the characteristic and mechanism of nitrogen and phosphorus removal by aerobic granular sludge were explored.The experimental results show that aerobic granular sludge is cultured in sequencing batch reactor(SBR) with decreasing the sludge sedimentation time and increasing COD loading rate resulting in the selective pressure. The aerobic granular sludge has a very compact and regular structure with a diameter of 0.5 to 1.0mm and a clear outer shape, the Sludge Volumetric Index (SVI) and the Mixed Liquid Suspended Solid (MLSS) are as high as 27.0ml/g and 6800mg/L, respectively. Compared to conventional activated sludge floes, aerobic granular sludge has a regular, dense and strong physical structure, good settling ability, high biomass retention, and the ability to withstand shock-loading rate.Simultaneous phoshporus and nitrogen removal was achieved by aerobic granular...