An eco-friendly approach towards treatment of tannery lime liquor using halo tolerant alkaliphile of extreme origin

Abstract

The management of tannery lime liquor using halo tolerant bacterium of extreme origin (accession number MTCC 5899) is reported in the present study. The isolate is capable to bring simultaneous reduction in pH as well as Total Dissolved Solids (TDS) of highly alkaline lime liquor (∼13.6 pH) within a reasonable time period. The strain is found to be growing at a wide range of pH (9.0–13.6) and salt concentration of 0–10%. Factors like amount of inoculum, dilution of liquor, type and concentration of carbon and nitrogen source used and initial TDS levels were observed to have a profound effect on the neutralization and reduction in TDS levels of lime liquor. A reduction in BOD5 and COD by ∼62% and 65% respectively was observed when the liquor was added with suitable carbon source. The present study was targeted to exploit the ability of alkaliphilic bacteria to reduce pH in order to provide an economic process for the nullification of highly alkaline lime liquor along with reduction in TDS, eventually making the liquor environmentally safe for discharge. This study paves way to greener route towards the treatment of tannery lime liquor, for the first time using halo alkaliphilic Micrococcus sp.