Following up on the informative October Centennial News article describing the Highland Creek wastewater treatment plant, the community should also be aware that the current multi-hearth incinerators at the plant are more than 50 years old. A great deal of money and work has kept them operating safely.
In 2004, the city’s Biosolids Master Plan considered this plant to be obsolete and at the end of its service life for sludge/biosolids management, and recommended replacement by updated technology – fluidized bed incinerators with enhanced pollution control systems.
Our community neighbourhood liaison committee supported the 2004 recommendation and we worked for many years for the fluidized bed incinerator against strong opposition that supported the alternative “beneficial use” option for managing biosolids/sewage sludge. This option would have required trucking tonnes of biosolids through our streets every day, for use as fertilizer on agricultural land, a questionable practice because sewage sludge contains pathogens and many untreated chemicals that can get into soil, silage, water run-off, and some foods.
After many years of setbacks, in 2016 Toronto City Council approved new fluidized bed incinerators as the best option for the Highland Creek plant. We cheered then, but thecurrentproposed date for this installation to be completed is 2029. Fluidized bed incinerators are being used successfully for on-site sludge disposal in the adjacent regions of York, Durham and Peel, and also in the city of London. The looped system is carbon neutral because minimal or no additional fuel source is necessary for its operation. The current plant uses significant amounts of natural gas/methane, a more potent greenhouse gas, for fuel.
The 2004 Biosolids Master Plan included a “Comparison of Measured Emissions Rates for Multiple Hearth and Fluidized Bed Sewage Incinerators,” showing significant reductions in emissions of numerous toxicants, metals, e.g. lead, mercury, and volatile organic compounds such as benzene. Organics and pathogens are removed by the very high heat incineration in the fluidized bed incinerators. A more recent City of Toronto document comparing options for the Highland Creek plant reported that dioxins and furans are destroyed by the fluidized bed incineration process at 99.96% efficiency.
Over the years, the Neighbourhood Liaison Committee distributed lawn signs, made deputations to city committees, provincial and city representatives, and worked for a comprehensive environmental assessment that found once again that fluidized bed incinerators were the best option for our neighbourhood.
To quote from the 2015 EA health study: Most predicted air concentrations [from the fluidized bed incinerator] were many orders of magnitude below their corresponding health-based reference benchmark (typically between 3 and 12 orders of magnitude below), Final Human Health Risk Assessment Report (intrinsik 2015).
It will be important that community members serving on the Highland Creek Neighbourhood Liaison Committee (HCNLC) follow and support the progress of the fluidized bed incinerator installation. Our group worked for an updated plant at Highland Creek that would result in cleaner air and health benefits for citizens locally and regionally. To install fluidized bed incinerators is a big engineering project, but it is disappointing that it has been such a long and rocky road to accomplish what the city plan for biosolids management recommended almost 20 years ago.