Effect of Influent Volumetric Loading of Skim Latex Wastewater on Anaerobic Sulfate Reduction

Wastewater generated in skim latex industry is rich in high sulfate concentrations, ammonia and protein. This research study investigates the effect of influent volumetric loading of Skim Latex Wastewater (SLW) on anaerobic sulfate reduction. Experiment was conducted using two semi-batch reactors operated under completely anaerobic condition. Operating volume and the temperature were 2.5 litre and 35 ±1°C respectively. This experiment was conducted in three phases VL01, VL02 and VL03 by feeding the reactor at 33.2 l/m3.d, 50.0 l/m3.d and 100.0 l/m3.d respectively. SLW contained influent COD/SO4−2 ratio of 2.7, whereas the influent COD/TKN (Total Kjeldahl Nitrogen) ratio was 10.1. Complete sulfate reduction was observed in all phases under anaerobic condition. However, the least average rate of sulfate reduction and overall percentage sulfate reduction was observed for the 100.0 l/m3.d. During this phase, anaerobic reactor showed symptoms of overloading, unstable and most affected with shock load. In VL03, time taken for complete sulfate reduction increased by 77.5% as a result of the high rate of ammonia formation. For SLW, sulfate degradation reduces at higher volumetric loading, but for moderate volumetric loading sulfate reduction was efficient, and ammonia inhibition could not be observed.