Anaerobic Nitrogen, Sulfide, and Carbon Removal in Anaerobic Granular Bed Reactor

Industrial wastewater may contain high concentrations of sulfides (S2-) and nitrates (NO3-), which must be removed before discharging into water bodies. The inhibitory effects of 134.82-771.9 mg L-1 d(-1) of sulfide loading rate (SLR) and 58.79-337.56 mg L-1 d(-1) of nitrate loading rate (NLR) on methanogenesis were investigated in a mixed methanogenic condition using palm oil mill effluent (POME) as carbon source. This technique cultivated mature granules using anaerobic sludge of POME as seed sludge, incubated in denitrifying sulfide removal medium to acclimate the denitrifiers. Biological denitrification was used to eliminate carbon, nitrogen, and sulfur in an anaerobic granular bed reactor of 4.5 L by varying hydraulic retention time of 16 h from 241 to 300 d. The maximum nitrate and sulfide removal efficiencies were observed up to SLR and NLR of 188.42 mg L-1 d(-1) and 82.39 mg L-1 d(-1) respectively. Maximum volatile fatty acid removal of 82% and methane 65.5 mL g(-1) of POME was obtained on SLR and NLR of 230 and 100.62 mg L-1 d(-1). (c) 2013 American Institute of Chemical Engineers Environ Prog, 33: 1096-1104, 2014