Hydrogen sulfide and turbidity control using catalysed oxidation coupled with filtration for groundwater treatment

The presence of hydrogen sulfide in drinking water supplies can result in odour complaints, sulfur induced corrosion and black-water problems in distribution systems. Conventional approaches for hydrogen sulfide control are based on either air stripping to remove nonionized H₂S or oxidation to form sulfate. Residual hydrogen sulfide can react with chlorine or chloramines resulting in the generation of turbidity in the distribution system, potentially compromising disinfection effectiveness. A promising alternative is to employ hydrogen peroxide oxidation catalysed by iron to form elemental sulfur that can be removed by filtration. Bench and pilot-scale tests were conducted on a Florida groundwater to evaluate reaction kinetics and process efficiency. The use of in-line hydrogen peroxide oxidation catalysed by low dosages of ferric sulfate coupled with two-stage upflow filtration was capable of complete removal of hydrogen sulfide and associated turbidity. Additional benefits of this physical/chemical treatment approach include elimination of odour generation, reduction of chlorine demand and improved stability of the finished water.