Design Features and Operational Effect of Tuandao WWTP Upgrading by MBBR in Qingdao

To solve problems,such as much higher actual influent quality than design standards,stricter effluent discharge standard and no land for development in the Tuandao WWTP in Qiangdao City,the existing improved A2/O process of WWTP should be upgraded.It should be a priority to ensure anoxic zone volume for denitrification,and lack of nitrification volume could be compensated by dosing SPR-1 biological filter media.In the combined process of biofilm and activated sludge newly adopted in the aerobic zone,the filling rate is approximately 29%,suspended sludge age is 5.5 d,biofilm sludge age was approximately 24 d,and medium and small diameter perforated pipes are used in the aeration system,without addition of the blower.The system has operated well since being upgraded three years ago,with strong resistance to impact load.The removal of nitrogen and phosphorus could be enhanced simultaneously,and refractory organics could be removed to some extent.The main quality indicators met the first level A criteria.There was good fluidized state of the filler in the whole system,and filler accumulation and screens clogged did not appear.The operational energy consumption after upgrading was almost the same as before upgrading.The combined process could significantly reduce the work amount,with a low operation cost,easy operation and management,high process efficiency and stability.It can be used in solving problems of municipal sewage plant upgrading.