Fan Testing of an Interceptor Sewer To Design an Air Management Facility

An air management facility is proposed to mitigate odors from the Highbury Interceptor – a 3m diameter interceptor sewer in the City of Vancouver. The facility will continuously withdraw and treat air from the sewer to maintain negative pressure in the headspace and prevent the release of odor within the zone of influence of the facility. In order to size the odor control system and delineate the zone of influence, a full-scale fan test was performed.The fan test involved shipping a 37 kW fan to site complete with generator, VFD, and carbon scrubber, and operating the equipment for a week. The fan inlet was ducted from a nearby manhole, and the fan was operated at flow rates from 200 m3/min to 450 m3/min. In order to quantify the effect of the fan operation, differential pressure sensors were installed in manholes and vents along the 6km long interceptor. Overall, the fan testing study successfully demonstrated that an odor control facility in the proposed location can maintain negative pressure within a significant section of the interceptor sewer and thereby mitigate odor complaints.