Biosorption of Chromium from Tannery Effluent Using Bacterial and Fungal Species

Abstract

Tannery effluent was collected from Common Effluent Treatment Plant, Dindigul, Tamil Nadu and used for analysis for physico-chemical, heavy metals and biological properties. Soil samples were collected from the field and Aspergillus sp. and Pseudomonas sp. were isolated and pure cultured. The pH of the tannery waste water was around 8.50 and electrical conductivity was 2.89 dS/m indicating the alkalinity of the effluent. Total dissolved solids(TSS) was found to be 1460 mg/L and BOD showed 2346 mg/l. The AAS reading of chromium in the effluent indicated 205 mg/L which means the effluent can not be released into the environment without proper treatment. The metal tolerance capacity of the organisms was tested at different concentrations of chromium salts dissolved in tannery effluent viz., 25 to 200 ppm with 25 ppm of increment for each of the treatment. Pseudomonas sp.tested tolerated upto 100 ppm,while the Aspergillus sp could resist upto 75 ppm of chromium concentration. It was also found that the Pseudomonas sp. had potentially removed chromium from aqueous spiked solution with effluent, hence it could be a good biosorbent for the removal of chromium from tannery effluent contaminated agricultural fields.