Application Study on the Treatment of Paper-making Wastewater Using Chitosan / Polyacrylamide / Polyaluminium Chloride Flocculants

In order to improve the coagulating performance of traditional polyaluminium choride /polyacrylamide flocculant( PAC / PAM), the preparation of chitosan / polyacrylamide / polyaluminium choride( CTS / PAM / PAC) composite flocculants was studied and the effect of flocculants dosage,p H,mixing rate and mixing time on removal efficiency of CODcrand turbidity were also investigated. It was found that coagulating performance is the highest when the component and dosage of composite flocculants were 12 mg / L of CTS,60 mg / L of PAM and 200 mg / L of PAC under the condition of p H = 7. 2,mixing rate of 80 r / min and mixing time of 8 min,respectively. The removal efficiencies of CODcrand turbidity reached 53. 9% and 98. 6% by using composite flocculants. The removal efficiencies of CODcrand SS were respectively increased by 13. 2% and 5. 9%,and the cost of the composite flocculants was decreased by 21. 1%,compared with the conventional flocculants PAC / PAM. Therefore,CTS / PAM /PAC flocculants had obvious economic and environmental benefits.