RESEARCH ON PARAMETERS OF ENHANCED?COAGULATIONIN THE SEDIMENTATION TANK SLUDGE WATER REFLUX PROCESS

摘要

In this paper, a beaker test is conducted for the research of the coagulation effect enhanced by sedi-mentation tank sludge water(hereinafter referred as STSW)reflux,The impact of differentparameters of poly aluminum chloride ((hereinafter referred as PAC)dosage, sludge water turbidity and reflux ratio on coagulation enhancement in the sludge water re-flux process are analyzed.The results indicate that when PAC dosage is less than 30mg/L,the STSW turbidity is between 16NTU and 40NTU, the reflux ratio is from 2%to 10%,and the STSWreflux pro-cess can facilitate colloidal flocculation in water, en-hance the coagulation effect, and improve the efflu-ent quality. Through the designed orthogonal test,it turns out that the optimal reflux conditions are:sludge water reflux ratio = 6%,PAC dosage =25mg/L,saving28.6%dosagecompared with that in process without STSW reflux,and sludge water tur-bidity = 30NTU.