A national strategy for abatement of odorous emissions at sewage treatment works in Singapore

Abstract

To provide an indication of the significant sources of odor from the different existing process units, a field survey was conducted to estimate the odor emissions (H2S, NH3, total hydrocarbon expressed as CH4) at representative locations at the Kranji Sewage Treatment Works (KSTW) in Singapore. KSTW provides secondary treatment to flows of domestic sewage and industrial effluent. Sampling locations were selected to include all the major foul air sources at the KSTW comprising of process units at the inlet works such as the inlet screw pumps, screens, and detritor channels; liquid treatment units such as primary settling, aeration, and secondary settling tanks; sludge thickening units and sludge treatment units such as elutriation tanks, filter presses and the dewatered sludge cake storage area. The results are used for the design of odor treatment systems for the existing units and for the extension works module, and will provide data to model the dispersion of odor in the vicinity of the KSTW. The planning and design of new odor control systems require the considerations of several important factors, including the evaluation of the existing odor control systems such as the state of the existing covers provided over current process units, the extent of the existing odor masking system and the provision of activated carbon filters.