Application of enhanced softening process in slaughterhouse wastewater treatment

• Published in: Indian journal of chemical technology 2013-05, Vol.20 (3), p.217-221
• Main Authors: Hossaini, H, Fatehizadeh, A, Yousefi, N, Reshadat, S, Rajabi Gilan, N, Ghasemi, S R, Ahmadian, M
• Format: Article
• Language: English
• ISSN: 0971-457X

Enhanced softening has been applied for the removal of soluble chemical oxygen demand (SCOD), phosphorous and colour of the abattoir effluent, and the effect of increasing dose of coagulants is investigated. The study is performed on a laboratory scale by using jar apparatus, lime as softener and pH adjuster agent. Coagulants such as alum and ferric chloride are used to increase the size of floes in various pH solutions. The results show that the enhanced softening is an efficient method for SCOD, and colour and phosphorous removal from abattoir wastewater. The maximum SCOD (93%) and phosphorous (94%) removal is attained at pH 11.65. Use of alum as coagulant combined with enhanced softening does not have positive effect on enhanced softening efficiency in SCOD, and phosphorous and colour removal, but ferric chloride increases the enhanced softening efficiency except its SCOD removal efficiency. The results also show that ferric chloride removes 90% and 97% SCOD and phosphorous respectively. This efficiency is obtained at 11.57 pH and 90 mg/L ferric chloride. The optimum pH and dose of ferric chloride (90 mg/L) increase the luminance of effluent from 40% to 75% at pH 7.6 and decrease its purity from 47% to 14% at pH 7.6