Chemical treatment of swine wastewater

Abstract

Chemical treatment processes can be applied in conjunction with physical and biological processes to effectively treat swine wastewaters. This study investigated the optimum dosage and the effectiveness of five different chemical treatments on low, medium and high strength wastewaters. Effectiveness was measured primarily in terms of suspended and total solids removal, and biological and chemical oxygen demand reduction. Phosphate removal was also measured but not optimized. The results showed that for all wastewater strengths, a low dosage of the polymer PERCOL 728 was the most effective. This polymer was excellent at solids removal, increasing the removal efficiency by approximately 20%. It was also effective at reducing the biological and chemical oxygen demands of the wastewaters. However, PERCOL 728 was the least effective of the chemicals in the removal of PO₄‐P; lime and alum proved more effective than FeCl₃ in this capacity. The PO₄‐P removal trend was for efficiency to increase with dosage strength. Given this, the amount of chemicals required to maximize PO₄‐P removal is so high that such treatment becomes impractical. The biopolymer chitosan was ineffective at solids removal and is not recommended for waste treatment.

Key words:

• swine manure
• chemical treatment