ABOUT THE PROJECT
Biorem has conducted a successful demonstration of high rate odour control at Preston Wastewater Treatment Plant in Cambridge, Ontario over the last three years. The system treats exhausts from primary clarifier and intermediate pump station. A combination of biotrickling filtration (BTF) and biofiltration (BF) processes was used in a novel horizontal flow configuration. XLD, a media developed specifically for organic sulphur compounds (OSCs) and total odour removal was used in the biofilter.
The system achieved 100% hydrogen sulphide (H2S) removal within four days and 95% OSC removal within 25 days from start. It has maintained this performance since its start-up in 2009. Odour removal was measured at 95% in as little as eight-second empty-bed residence time (EBRT), which is determined by dividing the volume of biofilter media by air flow rate. The horizontal flow configuration made it possible to use a 3.5 m high biofilter bed, resulting in an estimated footprint reduction of up to 75% over a more common vertical flow type system, while maintaining a pressure drop of less than 0.75 kPa. However, the vertical flow approach is just as valid, and the key to superior performance is selecting processes and biofiltration media suited to a given application.