Lab-scale degradation of leather industry effluent and its reduction by Chlorella sp. SRD3 and Oscillatoria sp. SRD2: a bioremediation approach

The present study focuses on treatment of tannery effluent samples using microalgae and isolated cyanobacteria. Different concentrations of both the effluent samples were treated with the algal isolates and a highest biomass of 0.295 g/l was attained in 50% of concentration on the 12th day in BHEL site. The biomass production in Walajapet site was found to be 0.387 g/l in the effluent treated with 50% of algae. The treated effluent was tested for growth and chlorophyll content was estimated, Chlorella sp. SRD3 showed higher chlorophyll content. The 50% treatment was processed at large-scale treatment in lab and biomass yield of 0.65 ± 0.04 g/l was achieved in BHEL site and 0.49 ± 0.028 g/l in Walajapet site. The treatment led to higher reduction rates in BOD and COD levels in treated effluents. The BOD in effluent from BHEL site was reduced to 83.41% and that from Walajapet site showed 87.46% reduction, whereas the COD values also showed 78% reduction. Based on the results, effluent sample serves as a medium for growth and bioremediation of tannery effluents by microalga, Chlorella sp. SRD3 revealed promising results which may prove efficient in the near future.