A physicochemical treatment was applied to study on removal of commercially used reactive dye and investigate the effectiveness of coagulation-flocculation from textile wastewater. Three types of coagulants were used like udaluminium sulphate (alum), polyaluminium chloride (PAC), and magnesium chloride (MgCl2). Polyelectrolyte, Koaret PA ud3230 was used as the coagulant aid. The coagulant dosage between 400 ppm to 5,000 ppm was studied using jar test. The udchanges of pH, types and dosage of coagulant, and the udaddition of coagulant aid on the percentage removal and the udconcentration of the dyes were determined through colour udpoint. The results show that up to 90% colour removal for udreactive dye could be achieved using alum of concentration ud6,000 ppm and pH 2.4. Meanwhile, 99 % colour removal could udbe achieved using MgCl2with concentration of 4,000 ppm audnd pH 10.4, whereas 100% colour removal could be achieved udusing PAC with concentration of 2,000 ppm and pH 4.1. Among udthe coagulants used, PAC was the most effective coagulant in udtreating each dye, with the colour removal up to 100% at the uddosage of 800 ppm. The flocs settling time for the treatment udwith MgCl2 was shorter than the treatment with PAC and the udtreatment with Alum was longer than the treatment with MgCl2 and PAC. This result can contribute some knowledge on the use of effective coagulants in treating textile industrial wastewater.
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