Volume No. 6 Issue No.: 3A Page No.: 594-600 Jan-Mar 12

 

A MICROBIOLOGICAL PROCESS FOR COMBINED BIOELECTRICITY PRODUCTION AND WASTEWATER TREATMENT USING Staphyllococcus Sp.

 

A.V. Pethkar*1, Kalyani Kale1, Priyanka Belgaonkar1, Vaishali Bagul

1. Deptartment of Biotechnology, KTHM College, Gangapur Road, Nashik, Maharashtra, (INDIA)
2. Deptartment of Electronics, KTHM College, Gangapur Road, Nashik, Maharashtra, (INDIA)
3. Deptartment of Microbiology, KTHM College, Gangapur Road, Nashik, Maharashtra, (INDIA) *E-mail: avpethkar@yahoo.com

 

Received on : July 10, 2011

 

ABSTRACT

 

The dwindling supply of energy resources and the concomitant rise in cost of fuels pose severe problems for mankind. Moreover, there are concerns about environmental harm either during production or use of the energy sources. Significant advances have been made in the search for new methods of tapping energy that will be cheaper, sustainable and environmentally safe. Bioelectricity which can be generated through the metabolic activities of microorganisms has been recognized as a potential source of renewable energy. A large number of research papers have been published on the topic and the design of Microbial Fuel Cells (MFCs) for b ioelectricity production has been described. The MFC may well become the Mantra of the modern time. MCF is an electrolytic cell with two chambers connected by a salt bridge. One chamber has microbial cells at high density and an anode, while the other chamber contains electrolytic buffer with cathode. Microbes utilize a substrate provided in the anodic chamber and generate electrons as a byproduct of metabolic activity. Under anaerobic conditions (absence of electron acceptor such as oxygen) the electrons are trapped by the anode. The electrons are subsequently transferred through an external circuit to the cathode. Protons that are also generated in the anodic chamber are carried through the salt bridge to the cathodic chamber, where they interact with O2 and electrons to generate water molecules. Efforts were undertaken in order to use MFC for treatment of wastewater coupled to bioelectricity production. Simulated wastewater and real wastewater of a paper industry were treated in anodic chamber of MFC that contained either a mixed bacterial consortium or pure isolate identified as Staphylococcus sp. that was isolated from a municipal anaerobic sludge sample. Initially, the organisms were studied for the ability to produce bioelectricity from simulated wastewater by optimizing different parameters viz. electrode surface area, distance between electrodes, resistance of external resistor, glucose concentration, type of salt bridge, etc. It was found that Staphylococcus sp. generated more electricity than the mixed consortium. The optimized parameters for a 1liter MFC viz. surface area- 100 m2, distance between electrodes- 6 cm, external resistor- 50 ?, glucose concentration- 10g/L could generate 7.2 mV of electric potential and the peak level was reached in a period of 5 h. Subsequently, experiments were repeated with real wastewater sample obtained from a paper industry and it was found that an electric potential of 3.6 mV was generated in 3-5 h. Bioelectricity production was accompanied by simultaneous reduction (78%) in COD levels of wastewater. The experiment was continued for up to 21 days under controlled conditions with intermittent substrate addition and it was found that the levels of electricity generation and COD reduction remained constant during this period. Further experiments are underway in order to make the design of the MFC more efficient and handy for fruitful applications.

 

Keywords : Microbial fuel cell, Wastewater treatment, Bioelectricity, Staphyllococcus, Microbiological

 

 

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