A Study On Operational Control Of SBR Process With Sludge Transferring

The concept of sludge transferring was developed to resolve the problem of lowwater filling ratio,the inefficient removal Nitrogen or phosphorus,insufficient stabilityin existing SBR and its derivative process. Sediment load was reduced and waterfilling ratio was increased by the activated sludge transferring between different SBRreactors. At the same time sludge transferring could improve the stability of theoperation. The experiment treat Sewage with sludge transferring process inLaboratory conditions. The experimental results as follows:（1）The Amount of sludge is increased in the Reaction stage, the more Sludgereflux ratio gets, the more Amount of sludge transfers. The Amount of sludge at30%Sludge return ratio is increased by35%than0%Sludge return ratio.（2）The SBR process with sludge transferring can effectively increase the waterfilling ratio and handling capacity without affecting processing. water filling ratio isincreased from30%to45%under the condition of30%sludge reflux ratio. Thehandling capacity is raised from60L/d to90L/d. at the appropriate condition:30%sludge reflux ratio, filling with stirring, filling with aeration, aeration, sedimentationand decanting; The effluent COD、ammonia nitrogen、TN、PO43--P concentrations are40mg·L^-1、2.8mg·L^-1、8.5mg·L^-1、0.04mg·L^-1. The average removal rate of COD、ammonia nitrogen、TN、PO43--P are81%、94%、64%、96%.（3）Sludge transferring could improve the performance of sludge settlement. Atthe condition of30%sludge reflux ratio, the SVI can reduce from436mL·g^-1to117mL·g^-1. Sludge transferring can also improve phosphorus removal performance, themore amount of sludge transfers, the faster the sludge transfer of frequency gets,bio-selector will release more phosphorus, removal of phosphorus becomes better.（4）In the method of mass balance, it is concluded that51%of TN is removed inaeration by means of Simultaneous nitrification and denitrification at the condition ofappropriate conditions. DO concentration has a great impact on the removal of TN.When the DO concentration changes from0.7mg·L^-1to2.5mg·L^-1in aeration, theremoval of Nitrogen is efficient and stable.（5）Sludge bulking has a negative influence on Sludge transferring. Thesynergetic effects of low organic load(0.1～0.2kg（COD）/kg（MLSS d） and longsludge age （20d） lead to a severe sludge bulking,SVI increased by303mL·g^-1. Bychanging the mode of inflow, the settling performance of the sludge gets control and recovers. SVI can be stabilized at100mL·g^-1eventually. Deterioration of SVI wasobserved after the change of composition of domestic wastewater. The sludge had ajelly-like viscous consistency with a great amount of exocellular slime. After slimedisappeared, the viscous bulking was restricted by simulating earlier wastewatercomposition and reducing SRT. The sludge settleability recovered in a short time. SVIcan reduced to105mL·g^-1in the end.