Removal of Reduced Species from the Effluent of UASB Reactor Treating Domestic Wastewater

This paper deals with an upflow anaerobic sludge blanket (UASB) reactor's effluent post treatment under aerobic conditions. The kinetics of stripping and oxidation of sulfides (H2S, HS- and S2-) and purgeable organic compounds are determined. The effects of dissolved oxygen (DO) and temperature on stripping and oxidation kinetics are also investigated. Batch results indicate that the effluent quality [sulfide, chemical oxygen demand (COD) and purgeable organic carbon (POC)] can be improved by 50% with aeration at 6 mg/L DO and at hydraulic retention time (HRT) of 30 min. The results obtained in the batch studies were confirmed in full size reactors. Moreover, it was observed that sulfides in absence of dissolved oxygen are removed by stripping rather than oxidation.