Development of the Sulphidogenesis Cum Ammonia Removal Process for treatment of tannery effluent

The present paper describes the development of Sulphidogenesis Cum Ammonia Removal Process (SCARP) with a simple sulphide inhibition control. The process was developed using synthetic effluent and its application for treatment of primary treated tannery effluent was demonstrated. This paper also discusses the effects of HRT and loading rates. The developed SCARP could treat efficiently the primary treated tannery effluent with influent concentrations of COD, SO₄²⁻ and NH₄⁺ equal to 3,900 mg/L, 3,000 mg/L and 300 mg/L, respectively. An HRT of 10.5 hours was found to be adequate for COD, NH₄‐N and SO₄²⁻ loading rates of 8.9 kg COD/m³/d, 0.68 kg NH₄⁺/m³/d, 6.84 kg SO₄²⁻/m³/d, respectively. The overall removal efficiencies of COD, NH₄‐N and SO₄²⁻ for the above loading rates were in the ranges of 90.8–91.8%, 84–88.3% and 64.2–70.2%, respectively. The system performance was satisfactory for different loading rates and low COD/SO₄²⁻ ratios. The developed SCARP has good potential as a cost effective alternative treatment process to existing extended aeration process with nitrification–denitrification for the secondary treatment of tannery effluent.