Removal of turbidity and E. coli from surface water by electrocoagulation and study of its economic feasibility

Civil Engineering Department, M. N. Dastur School of Material Science and Engineering,

Indian Institute of Science Engineering Science and Technology, Shibpur, Howrah-711 103,

West Bengal, India

E-mail : ray.soumya5@gmail.com, chanchal@civil.iiests.ac.in, senjitiitkgp@gmail.com

Manuscript received 15 November 2017, revised 01 March 2018, accepted 07 March 2018

Maximum turbidity removal of 98% is obtained in treatment of raw surface water by electrocoagulation (EC) system. As per World Health Organization (WHO) the permissible limit of turbidity of below 5 NTU can be achieved at a charge loading (CL) of 18 Coulomb/L at a pH value of 7.25. EC followed by plain sedimentation and filtration can remove of 19% of E. coli from raw water. Disinfection of filtered water is done by sodium hypochlorite solution (4% available chlorine). The complete (100%) removal of E. coli is achieved at a chlorine dose of 2.8 mg/L within 30 min of contact time. The treatment cost per liter of water estimated to be Rs. 0.072 per liter.