Using Polymers as Coagulants for Treatment of Soap Industry Wastewater

Abstract

Nowadays, Water scarcity is considered a critical issue that faces the majority of countries, especially Egypt. So, searching for alternative water resources is deemed to be the ideal solution. Due to the large amount of wastewater produced from the soap industry, reusing soap wastewater after applying a proper treatment technology is a good idea to achieve effective sustainability between water resources and the irrigation field. In this experimental study, various types of polymers were used as flocculants to collect the small size particles and settle them under gravity.   Aluminum Chloride – polyacrylamide polymer (AlCl₃-PAM) and polymethyl methacrylate grafted oatmeal (OAT-g-PMMA) were prepared in the lab under specific synthesis conditions. Three experimental trials were performed. First, wastewater passed to flotation tank and aeration tank with hydraulic retention time (HRT) of 8 hours and 16 hours then settled in a final settling tank with HRT of 3 hours. At the second and third trials, soap wastewater was fed into a flocculation tank where (OAT-g-PMMA) and (AlCl₃-PAM) were added with a dosage of 2.5 mg/l and 0.8 m/l, respectively to perform the flocculation process then wastewater was passed to aeration tank where biological treatment was performed with HRT of 16 hours then effluent wastewater passed to settling tank to settle inorganic substances produced from the biological treatment process. (OAT-g-PMMA) was effective in reducing COD and TSS with a removal efficiency of 63%, and 66%, respectively. (AlCl₃-PAM) was more effective than. (OAT-g-PMMA) as it was effective in achieving COD removal efficiency of 82%, and 81.5% for TSS. The effluent wastewater characteristics in case of using (AlCl₃-PAM) and (OAT-g-PMMA) were below the limitations of Egyptian code for reuse in irrigation purposes.