Study on the Advanced Treatment of Papermaking Effluent by Membrane Separation Technology

The optimum condition for the advanced treatment of the papermaking effluent from secondary biochemical treatment stage by using flocculation precipitation pretreatment and membrane separation technology was studied.The result showed that polyacrylamide(CPAM) and poly aluminum ferric chloride(PAFC) were 1.5 and 150 mg/L respectively,the effluent could meet the requirements of ultrafiltration(UF) after flocculation.The filtration efficiency was better when operating pressure of ultrafiltration membrane was at 0.04~0.10 MPa,the membrane flux was between 12~17 L/h.The effluent after nanofiltration(NF) treatment and reverse osmosis(RO),electrical conductivity droped to about 12 μS/cm,the CODCr removal reached more than 90%,the turbidity of the effluent was undetectable,the treated water quality was close to or even better than the clean water,and fully met the quality standards of reused water.The CODCr of concentrated water was 85.3 mg/L after the RO treatment and met the requirement of the new National Papermaking Industry Effluent Pollutants.