Study on the Suitable Chemical Agent for treating Waste Water from Paint Industries

Abstract

The studies were concerned on the treatment of waste water from the water base paint making processes of Prodular Paint Factory by coagulation process. Two coagulants were used in this experiments as aluminum sulphate and ferrous sulphate. The use of sodium sulfide for increasing of mercury removal efficiency was also investigated. Two types of waste water, were used in this study, were synthetic waste water solution and the real waste water from the factory.

For the water base paint process of Prodular Paint Factory, 0.5 cubic meter of waste water was produced per 1,000 gallons of paint production. The waste water had high concentration of color intensity, suspended solid, turbidity, COD, BOD and mercury as about 755-1,427 mg/l, 3,850-6,050 NTU, 1,172 – 1,685 mg/l, 24-32 mg/l and 0.217-0.454 mg/l, respectively

Treatment efficiencies of synthetic waste water by using aluminium sulphate as the concentration of 350, 400, 500, 550 and 600 mg/l, respectively and the initial pH of the solution was control as 5, 7 and 9, respectively and ferrous sulphate as the concentration of 100, 150, 200, 250, 300 and 350 mg/l respectively and the of the initial pH of the solution was control as 7, 9 and 11 respectively were investigated. The results showed that the optimal condition for treating the synthetic waste water by using were 500 mg/l of aluminium sulphate and initial pH as 7 and 250 mg/l of ferrous sulphate an initial pH as 9, respectively. The color of waste water was disappeared after treated by both aluminium sulphate and ferrous sulphate. Suspended solid, turbidity, COD and mercury of the waste water were removed about 99.60%, 99.68%, 84.80% and 85.06%, respectively an 33.80%, 99.76%, 93.71% and 85.55%. respectively when the coagulatants were aluminium sulphate and ferrous sulphate, respectively.

For the treatment of real waste water, the results showed that the optimal conditions for the aluminium sulphate and ferrous sulphate were 500 mg/l of aluminium sulphate and the initial pH as 7 and 250 mg/l of ferrous sulphate and initial pH as 7, respectively. The color of the waste water was disappeared after treated by both aluminium sulphate and ferrous sulphate. Suspended Solid, turbidity, COD and mercury of the real waste water were removal about 99.80%, 99.70%, 76.80% and 72.45%, respectively and 99.76%, 99.78%, 77.57% and 78.85% respectively. For removal of mercury from the treated waste water after treated waste water did not show any significant.

For the determination of treatment cost (only chemical agants cost, electricity cost and sludge disposal cost) by using the aluminium sulphate and ferrous sulphate were about 11 and 10 bath per cubic meter of water, respectively. But in the case of treatment by Samear Dam Industrial Waster Disposal Center, they would charge about 399 bath per cubic meter of waste water (this cost was included 70 Km transportation fee).