Journal of Environmental Biology

Disinfection of wastewater: Comparative evaluation of  

chlorination and DHS-biotower

Anju Pant and Atul K. Mittal*

*akmittal@civil.iitd.ac.in

Environmental Engineering Laboratory, Department of Civil Engineering,

Indian Institute of Technology, New Delhi-110 016, India

(Received: June 12, 2006 ; Revised received: December 05, 2006 ; Accepted: January 01, 2007)

Abstract: The present study reports the onsite evaluation of two pilot scale disinfection units. One of the pilot plants is based on chlorination, and other is based on fixed film aerobic process (biotower). Evaluation study consisted of onsite monitoring of COD, BOD₅ and TSS and fecal coliform over a period of three months. Samples were collected from the inlet and outlet of the pilot plants. These pilot plants were evaluated so as to have an appropriate disinfection technology for the treatment of the effluents from upflow anaerobic sludge blanket reactor (UASBR) based sewage treatment plants which could meet the biological quality standards. All the influents samples collected from both the pilot plants contained fecal coliform ranging from 10⁵ to 10⁶ MPN/100 ml. The results show that the fecal coliform removal is up to 98.2% and 100% for biotower and chlorination, respectively. Both, the chlorination and down hanging sponge-biotower (DHS-biotower) improved the quality of effluent from the UASBR in terms of COD, BOD₅ and TSS. Though chlorination performed better compared to the DHS-biotower, however, it has additional risk associated with the formation of trihalomethanes (THMs).

Key words:  Chlorination, Disinfection, Fecal coliforms, Municipal wastewater and UASB, Biotower

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