The study was carried out to compare the potential of E. coli, Bacillus spp., Pseudomonas spp., Xanthomonas spp. and Streptomyces spp. by observing different water quality parameters over a time period of 30 days of each test. Chemical Oxygen Demand (COD) was observed to be as much as three times of Biological Oxygen Demand (BOD) in raw effluent. Maximum BOD and COD reduction was by Pseudomonas spp. (79% and 72%) and minimum by Bacillus spp. (45%). BOD and COD reductions were found to be 70%, 65%; 60%, 57%; and 59%, 55% by E. coli, Xanthomonas spp. and Streptomyces spp. respectively. The reduction in nitrate and phosphate was observed as 75% and 68% by Pseudomonas spp., 67% and 55% by E. coli, 65% and 62% by Xanthomonas spp., and 62% and 57% by Streptomyces spp. The least reduction was recorded in the case of Bacillus spp. The study concluded that Pseudomonas spp. was the most potential bioremediating agent.

Intensification of agriculture and manufacturing industries has resulted in increased release of a wide range of xenobiotic compounds to the environment. Excess loading of hazardous waste has led to scarcity of clean water and disturbances of soil, thus limiting crop production (Kamaludeen et al., 2003). Bioremediation uses biological agents, mainly microorganisms, i.e., yeast, fungi or bacteria to clean up contaminated soil and water (Strong and Burgess, 2008). This technology relies on promoting the growth of specific microflora or microbial consortia that are indigenous to the contaminated sites that are able to perform the desired activities (Agarwal, 1998). Establishment of such microbial consortia can be done in several ways, e.g., by promoting growth through addition of nutrients, by adding terminal electron acceptor, or by controlling moisture and temperature conditions (Hess et al., 1997; Agarwal, 1998; and Smith et al., 1998). In bioremediation processes, microorganisms use the contaminants as nutrient or energy sources (Hess et al., 1997; Agarwal, 1998; and Tang et al., 2007).

An indication of organic oxygen demand content of wastewater can be obtained by measuring the amount of oxygen required for its stabilization either as Biological Oxygen Demand (BOD) or as Chemical Oxygen Demand (COD). BOD is the measure of the oxygen required by microorganisms whilst breaking down organic matter. While COD is the measure of amount of oxygen required by both potassium dichromate and concentrated sulphuric acid to break down both organic and inorganic matters. BOD and COD concentrations of the wastewater are measured, as the two are important in unit process design. Though BOD is a measurement of the oxygen required for microorganisms whilst breaking down organic matter to stable inorganic forms, such as CO₂, NO₃ and H₂O, the water with high BOD indicates organic pollution. COD is used as a measurement of the oxygen equivalent of the organic matter content of a sample that is susceptible to oxidation by a strong chemical oxidant. Usually, the concentrations of COD in surface water ranges from 20 mg/L or less in unpolluted water to greater than 20 g/L in water receiving effluents. Nitrogen-nitrate is the final oxidation product of nitrogen. Natural sources of nitrate to surface waters include igneous rocks, land drainage, and plant and animal debris. Natural levels, which seldom exceed 0.1 mg/L NO₃-N, may be enhanced by municipal and industrial wastewater, including leachates from waste disposal sites and sanitary landfills. In rural and suburban areas, the use of inorganic nitrate fertilizers can be a significant source. Phosphate is essential for the growth of organisms and can be the nutrient that limits the primary productivity of a body of water. In instances, where phosphate is a growth limiting nutrient, the discharge of raw or treated wastewater, agricultural drainage, or certain industrial wastes to that water may stimulate the growth of photosynthetic aquatic micro and macroorganisms in nuisance quantities.

Life Sciences Journal, Bioremediation Processes, Five Distinctive Microorganisms, Chemical Oxygen Demand, Biological Oxygen Demand, Xenobiotic Compounds, Crop Production, Biological Agents, Ferrous Ammonium Sulphate, Microbial Communities, Photosynthetic Aquatic Macroorganisms.