Pellet Flocculation Process Based On Enhanced Clarifier Applied To Low Turbidity Reservoir Water Treatment

Pellet flocculation process based on enhanced clarifier, developed in the enhancedclarifier and on the basis of pellet flocculation,is a new a new water treatmentprocess,and concludes coagulation, reaction, sedimentation, sludge returning.In thispaper,lots of researches have done about this topic. First of all, using a small test tosimulate the impact of factors of pellet flocculation process based on enhanced clarifier,and conduct a pilot test of feasibility of flocculation process for the treatment of lowturbidity water,and at the same time a pilot experimental study is carried out on lowturbidity reservoir water by pellet flocculation process based on enhanced clarifier. Inaddition, on the basis of the pellet flocculation process of pellet by adding micro-sand,a pilot experiment for the treatment of low turbidity, high algae water was conductedwith pellet fluidized bed with micro-sand.(1)Small pilot test: when simulate the return sludge, PAC dosage should not exceed25mg/L. If continue to increase the dosage, it can not continue to reduce thesupernatant turbidity and CODMn.The dosage of PAM has no effect on CODMn, but canimprove the supernatant turbidity.When the dosage of PAM was0.2mg/L, the supernatantturbidity was lower. If continue to increase the dosage, the supernatant turbidity but will rise.Return sludge can also improve the supernatant turbidity, but have no influence on the removalof CODMn. The dosage of return sludge was800mg/L, lower supernatant turbidity.Ifcontinue to increase the dosage, it has no significant improvement.(2) Pilot study of the pellet flocculation process. In front of suspended flocculation layer ofPellet destruction,when the dosage of PAC was5.0mg/L, the dosage of PAM was0.25mg/L, theeffluent turbidity can be stabilized under0.5NTU.However, the results show that the effluent willbe worse in case of damage of suspended lawyer.The pellet flocculation process for the treatment of low turbidity water is unstable.(3) Pilot study of pellet flocculation process based on enhanced clarifier: Theresults show that it is feasible to treat the low turbidity reservoir water using this newprocess. And the process has the characteristics of high stability, good effluent quality.When the upflow velocity is controlled at20m/h, the optimal operation parameters areas follows: the dosage of PAC is11mg/L, the dosage of PAM is0.25~0.30mg/L, theratio of the sludge recycle is3%, and the stirring speed is6r/min. under such conditions,the effluent turbidity can be controlled less than1.0NTU.(4) Pilot study of the pellet flocculation process of pellet by adding micro-sand:The results showed that it is feasible to treat the low turbidity and high algae waterusing this new process. And the treatment efficiency of which is significantly higherthan that of the technology of recycle sludge. The effluent turbidity and CODMncouldbe effectively reduced. When the dosage of micro-sand was0.50g/L,dosage of PAC was15mg/L,dosage of PAM was0.40mg/L,the stirring speed was8r/min, the effluentturbidity could be controlled under1.5NTU, and the CODMnremoval rate was morethan40%,and the algae removal rate was higher than80%.