Treatment of Highly Turbid Water by Polyaluminum Ferric Chloride (PAFCL)

Background & Aims of the Study: In some situation like rainfall seasons raw waterbecome very turbid so it affected the water treatment plant processes and quality ofproduced water. Treatment of very high turbid water has some concerns like precursors fordisinfection by-products and very loading rate of particle on filter s media and consequentlyincreases in water consumption for filter backwash. This paper investigates theperformance of a composite inorganic polymer of aluminium and ferric salt,Polyaluminium ferric chloride (PAFCl), for the removal of turbidity, color and naturalorganic matter (NOM) from high turbid water.Materials and Methods: Experiments were carried out by Jar test experiment by syntheticwater samples with 250 and 500 NTU turbidity that prepared in laboratory.Results: The results of conventional jar test showed that the optimum pH for coagulation ofwater sample was 7.5 to 8 and optimum dosage of the coagulant was 10 mg/L. Removalefficiency of turbidity, color and UV adsorbent at 254 nm at optimum dose and pH withoutfiltration was 99.92%, 100% and 80.6% respectively for first sample (250 NTU) and99.95%, 99.49% and 84.77 for second sample (500 NTU) respectively.Conclusion: It concluded that polyaluminium ferric chloride has a very good efficiency forthe removal of turbidity, color and organic matter in high turbid water. Also it can be selectas a coagulant for high turbid water and some waste water from water treatment plant likefilter backwash water.

Keywords:

coagulation , high turbidwater , polyaluminumferric chloride , watertreatment