Developing Tailor-Made Microbial Consortium for Effluent Remediation

The work describes a biofilm-based soluble sulphate reduction system, which can treat up to 1600 ppm of soluble sulphate within 3.5 hours of incubation to discharge level under ambient condition using a well-characterized sulphate-reducing bacterial (SRB) consortium. This system ensures the treatment of 1509 litres of sulphate solution in 24 hours using a 220-litre bioreactor. Performance of the system during series operation was compromised, indicating the presence of inhibitor in solution at a toxic level. A single unit bioreactor would be the ideal configuration for this consortium. Modified designs of bioreactors were tested for optimization of the process using response surface methodology (RSM), where the system could function optimally at an initial sulphate concentration of 1250 ppm with a flow rate of 1.8 litre/hour. The time course of sulphate reduction yielded a parabolic profile (with coefficient of determination r 2 = 0.99 and p value < 0.05). The rate of sulphate reduction was found to be independent of seasonal variation as well as the specific design characteristic