Short-term temperature impact on simultaneous biological nitrogen-sulphur treatment in EGSB reactor

摘要

Sulphides are present in many wastewater streams; their removal is important due to corrosiveness, toxicity and unpleasant odour, and can be carried out by anaerobic biological treatment. This study focuses on the temperature effect (25-10 degrees C) on an expanded granular sludge bed (EGSB) reactor for sulphide removal using nitrate as electron acceptor. The reactor was run at a NO3-/HS- molar ratio of 0.35 and pH of 8.5-9.0. Samples were analysed by ion chromatography (NO3-, SO42- and S2O32-), spectrophotometry (S2-) and by scanning electron microscopy (SEM). S2- and NO3- removal was 99.74 +/- 0.04 and 99.5 +/- 2.9%, respectively. Sulphur (S-0) was found on the outer granule surface and struvite inside the granule, by SEM. Sulphide conversion to sulphur was up to 76%. Temperature transitions and levels influenced S2O32- and SO42- concentrations.