Characterization and treatability studies of tannery wastewater using chemically enhanced primary treatment (CEPT)--a case study of Saddiq Leather Works.

Chemically enhanced primary treatment (CEPT) is a technology that uses coagulants for enhanced pollutants removal at the primary stage of the wastewater treatment. This paper presents the detailed characteristics of tannery wastewater. It also explains effectiveness of CEPT in removing pollutants from tannery wastewater using various metal salts. The results of this study demonstrated that the tannery effluent had high concentrations of organic matter, solids, sulfates, sulfides and chromium. Alum, ferric chloride and ferric sulfate were tested as coagulants using jar test apparatus. Alum was found to be the suitable coagulant for tannery wastewater in a dose range of 200-240 mg/L as Al(2)(SO(4))(3). With alum, percentage removal efficiency for turbidity, total suspended solids (TSS), chemical oxygen demand (COD) and chromium was found to be 98.7-99.8, 94.3-97.1, 53.3-60.9, and 98.9-99.7%, respectively. National effluent quality standards for total suspended solids and chromium were met after CEPT. However, COD content was high, emphasizing the need of secondary treatment for the tannery effluent.

[1]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[2]  Hallvard Ødegaard,et al.  Norwegian Experiences with Chemical Treatment of Raw Wastewater , 1992 .

[3]  H. E. Hudson,et al.  Conduct and uses of jar tests , 1981 .

[4]  S. Sözen,et al.  The effect of chemical settling on the kinetics and design of activated sludge for tannery wastewaters , 1998 .

[5]  M. Rebhun,et al.  Effect of properties of polyelectrolytes on their interaction with particulates and soluble organics , 1997 .

[6]  Vinod Tare,et al.  Case Studies on Biological Treatment of Tannery Effluents in India , 2003, Journal of the Air & Waste Management Association.

[7]  M. Rebhun,et al.  Strength of ferric hydroxide flocs , 1983 .

[8]  Raymond D. Letterman,et al.  Water quality and treatment : a handbook of community water supplies , 1999 .

[9]  A. O. Rangel,et al.  Constructed wetland systems vegetated with different plants applied to the treatment of tannery wastewater. , 2007, Water research.

[10]  D. Orhon,et al.  Characterization of tannery wastewaters for pretreatment - selected case studies , 1997 .

[11]  H. D. Stensel,et al.  Wastewater Engineering: Treatment and Reuse , 2002 .

[12]  H. Stechemesser,et al.  Coagulation and flocculation. , 2005 .

[13]  W. Weber.  Physicochemical processes for water quality control , 1972 .

[14]  Raymond D. Letterman,et al.  Influence of Rapid‐Mix Parameters on Flocculation , 1973 .

[15]  S. Kawamura.  Considerations on Improving Flocculation , 1976 .

[16]  K. Ives.  The Scientific Basis of Flocculation , 1978 .

[17]  J. Gregory.  Effects of Polymers on Colloid Stability , 1978 .

[18]  R. Aim,et al.  Effluent pretreatment by iron coagulation applying various dose-pH combinations for optimum particle separation , 1998 .

[19]  Riccardo Gori,et al.  Powdered activated carbon and membrane bioreactors (MBRPAC) for tannery wastewater treatment: long term effect on biological and filtration process performances , 2007 .

[20]  F. Chagnon,et al.  Design of a Chemically Enhanced Wastewater Treatment Lagoon in Brazil , 2000 .

[21]  I. Yu.  Bench-scale study of chemically enhanced primary treatment in Brazil , 2000 .

[22]  Hallvard Ødegaard,et al.  Optimised particle separation in the primary step of wastewater treatment , 1998 .