Papers by Keyword: Polyaluminium Chloride (PAC)

Abstract: Using chitosan-modified diatomaceous earth (DE) to treat micro-polluted water by coagulation/flocculation/sedimentation (C/F/S), the results indicated that the modified DE could apparently increase the removal rates of turbidity and UV₂₅₄ in comparison with adding DE alone, and the optimal ratio between chitosan and DE was 1:40. With the compounding of polyaluminium chloride (PAC) and modified DE, the treatment effect was obviously improved by coagulation aid of modified DE under adding the same PAC dosage. The best removal rates of turbidity and UV₂₅₄ reached 96.2% and 47.9% respectively with the PAC dosage of 35 mg/L and the modified DE dosage of 45 mg/L. The results indicated that the treatment effect of micro-polluted water improved with the enhanced coagulation of chitosan-modified DE.

Abstract: Using polyaluminium chloride (PAC) and chitosan as the main coagulant and coagulant-aid respectively, the high algae-laden water was treated by coagulation/flocculation/dissolved air flotation (C/F/DAF). When the doses of PAC and chitosan were both moderate (7.0~8.4 mg Al2O3/L of PAC and 0.6~1.0 mg/L of chitosan), the removal rates of turbidity, algae cells and TOC were all increased apparently compared with adding PAC alone. Especially, the residual aluminum concentration reduced significantly in treated water with the aid of chitosan. The structrue and strength of flocs formed by coagulation aid of chitosan were improved obviously, which proved that addition of chitosan could enhance the flocculation performance of PAC. So, in C/F/DAF process for removing algae, using chitosan as coagulant-aid can improve the flotation performance and reduce residual aluminum concentration in treated water.