Odors removal in sewage treatment plant using a combined bioreactor
复合式生物除臭反应器处理城市污水处理厂恶臭气体

A combined-bioreactor, consisting of a suspension-growth zone and an attachment-growth zone, was developed to treat odors in a municipal wastewater treatment plant in Beijing. The main odor materials emitted from sludge thickening tank and sludge dewatering facility were H2S and NH3. Elimination capacities of odors, effect factors and microbiological characteristic in the individual zone were investigated in this study. Results showed that the inlet concentrations of H2S and NH3 were 0.21 - 22.61 mg/m^3 and 0. 1 - 0.5 mg/m^3 , respectively. During the period of steady treatment, the effluent concentrations reduced to 0 - 0.06 mg/m^3 for H2S and 0 -0.02 mg/m^3 for NH3, H2S and NH3 could be removed effectively in the combined bioreactor. However, their removal mechanisms in the suspension-growth zone were very deferent from that in the attachment-growth zone. Most of H2S were biooxidized by acidophilic Thiobacilli in the attachment-growth zone while less H2S was dissolved in the water or biooxidized by non-acidophilic Thiobacill in the suspension-growth zone. Much more NH3 were removed by nitration in the suspension-growth zone, only few NH3 transferred to aqueous phase by chemical neutralization in the attachment-growth zone.