Effect of pH on Separation of Solid Content from Paint Contained Wastewater by a Coagulantflocculant Compound

Abstract

Chemical wastewater treatment is one of the attracting and common methods forwastewater treatment among the currently employed chemical unit processes. The use of coagulantflocculantcompound is one of the efficient methods for separating of paint and recovery of water.In this research, it was introduced and the effect of pH on removal of solid content from solutionwas studied experimentally. For this purpose, sludge and suspended solid content of the solutionwere determined in a jar test by measurement of UV absorption of treated solution and solidseparation percentage. The results showed that in pH range - , maximum efficiency of solidcontent removal was up to . Consequently, maximum paint removal was obtained in this rangeof pH. The separation of solid content of the solution was due to formation of aluminum hydroxide.As shown by the results, the reduction of potassium hydroxide as pH adjuster caused decrease ofpH and consequently decreases of aluminum hydroxide and solid content removal.