Troubleshooting odor complaints at a water pollution control center
The Comox Valley Water Pollution Control Centre is a secondary wastewater treatment plant that serves the City of Courtenay and the nearby Town of Comox in British Columbia. The facility is located in a rural area, beside the Strait of Georgia.
Soon after the plant began operating in 1984, the Comox Valley Regional District began to receive odor complaints from nearby residents. Reports of unpleasant odors tended to be concentrated along Curtis Road, which runs between the plant and the Strait, and were most common in late summer and early fall when offshore winds are prevalent in the area.
RWDI performed a range of analyses to gain insight into odor control issues at the facility. We began by reviewing and evaluating the performance of the wet chemical scrubber system: an apparatus through which exhaust from some of the plant is filtered before being released into the air.
To assess the scrubber’s efficiency, we needed to test its performance under a range of conditions; this required us to develop a customized hydrogen sulfide (H2S) delivery system that would let us run tests in real time. Because the scrubbing system’s chemistry was changing throughout the sampling process, our extensive equipment and highly qualified staff were needed to ensure that our tests and analysis would deliver the sound insights capable of informing effective adaptations. We also needed to ensure tight coordination between our team in the field and the team responsible for performing the lab work. Our offices in Vancouver and Guelph were able to collaborate seamlessly under considerable time pressure. In addition, we conducted a more comprehensive review of odor control practices throughout the plant. A complete odor measurement and dispersion modeling program was also completed to determine the most effective use of resources for odor mitigation. We also advised the Regional District about the latest developments in odor control technologies, with emphasis on interventions capable of delivering improvements at the Comox plant.
In 2016, our team delivered a complete odor emissions summary and dispersion modeling study to the plant’s operators and to staff at the Regional District. This information allowed Comox Valley authorities to make a sound, evidence-based decision about the odor control measures that would be appropriate for the plant, in order to minimize off-site odor impacts that had been affecting nearby residents.