Biological removal of phosphate from synthetic wastewater using bacterial consortium

Document Type: Research Paper

Authors

1 Division of Environmental Management and Biotechnology, DRDO-BU Center for Life Sciences, Bharathiar University, Coimbatore -641 046, TN, India.

2 Department of Environmental Sciences, Division of Environmental Engineering and Technology Lab, Bharathiar university, Coimbatore-641 046, TN, India.

3 Department of Environmental Sciences, Division of Environmental Microbiology, Bharathiar university,Coimbatore-641 046, TN, India.

4 Department of Environmental Sciences, Division of Environmental Engineering and Technology Lab, Bharathiar University, Coimbatore-641 046, TN, India.

5 Department of Environmental Sciences, Division of Environmental Microbiology, Bharathiar University,Coimbatore-641 046, TN, India.

Abstract

The biological phosphorus removal is a microbial process widely used for removing phosphorus from
wastewater to avoid eutrophication of water bodies. The study was aimed to screen the efficient phosphate
reducing isolates and used to remove phosphate from synthetic wastewater using batch scale process. The
three most efficient phosphate reducers were isolated and screened from eutrophic lake water and forest soil
samples. The total heterotrophic bacterial analysis of the samples showed the presence of about 38 phosphate reducers based on the minimum inhibitory concentration (MIC) test. Among them, Bacillus sp RS-1,
Pseudomonas sp. YLW-7 and Enterobacter sp KLW-2 were found to be efficient in phosphate reduction.
Among the individual strains, Pseudomonas sp YLW-7 was noticed to be 68% removal in MSM with glucose
at neutral pH. The consortium with combination of Bacillus sp. RS-1, Pseudomonas sp. YLW-7 and
Enterobacter sp KLW-2 was effectively removed the phosphate in the synthetic medium when compared to
individual strains. The phosphate removal was observed to be maximum of 92.5% in mineral salts
medium (MSM) at pH 7and 5, and 63.4% in synthetic phosphate solution at neutral pH with lactose as a carbon source by the consortium after 72 h. Thus the microorganisms may use the contaminants as nutrients
and as energy sources or it may be utilized by cometabolism. Therefore, these bacterial isolates might
be used in the remediation of phosphate contaminated environments.

Keywords