Volume No. 7 Issue No.: 1A Page No.: 416-420 July-September 2012




Brahmacharimayum Bharati1 and Ghosh Pranab Kumar*2

1. Centre for the Environment, Indian Institute of Technology, Guwahati (India) 2. Department of Civil Engineering, Indian Institute of Technology, Guwahati (India)


Received on : May 05,2012




Normally sulfate containing wastewaters from various industrial activities such as pulp and paper industries, mining and mineral processing, production of explosives, scrubbing of flue gases, petrochemical industries, galvanic processes, battery, paint and chemical manufacturing etc. is treated using physicochemical and biological methods. Even though physicochemical methods are effective, the overlying limitations of separation and appropriate disposal of the solid phase, relatively high cost and energy consumption limit their usage. Biological sulfate reduction has been recognized as an efficient method for sulfate removal from wastewater owing to heavy metal removal, recovery of metals from sulfide sludge and low sludge generation in spite of the major problem associated with the production of sulfide. The biological sulfate reduction process is mediated by a group of microorganisms known as Sulfate Reducing Bacteria (SRB). The SRB form a specialized group of microbes that use sulfate as terminal electron acceptor for their respiration. The presence of sufficient amount of electron donors is essential as a minimum COD to sulfate mole ratio of 0.67 is required for achieving theoretically possible removal of sulfate. Hence, in COD deficient wastewaters, addition of external carbon sources is a must in order to achieve complete reduction. Thus, the availability of carbon forms a critical limiting factor for the microbial activity. Usually low-molecular-weight organic compounds are utilized by SRB as electron donors. This study was carried out to analyze the potential of the enriched mixed consortium to utilize different carbon sources such as acetate, dextrose, ethanol, formate and lactate as the sole carbon source for reduction of sulfate. Out of the five sources, lactate was found to be the most efficient carbon source for the mixed consortium.


Keywords : Sulfate Reducing Bacteria (SRB), Biological sulfate reduction, Electron donors, Mixed consortium, Carbon source