The City of Toronto made several changes to the sewer use bylaws that impact food service establishments. The amendment gives Toronto Water the authority to require the installation of a new grease interceptor where Toronto Water determines that an existing grease interceptor is detrimentally affecting the municipal sewage works, and there are further requirements for the sizing and installation of the new grease interceptor.
More importantly for customers with existing interceptors, the amendment also directs food service establishments to operate and maintain their GI’s according to the requirements of a new Food Service Establishment Environmental Code of Practice. The Code of Practice contains two key requirements as follows:
- Clean before the grease and solids, combined, reach 25% of the GI’s liquid volume or every four weeks, whichever is earlier.
- General Manager of Toronto Water may authorize, in writing, servicing every eight weeks, if the grease and solids combined do not reach 25% of the GI’s liquid volume by four weeks, but the FSE owner/operator must confirm by taking daily readings.
The sizing of grease interceptors, a very imperfect science
Historically, GI selection has been driven by lowest cost and ease of installation. Small, under-sink grease interceptors are generally cheaper and have lower installation costs. As a result of the lack of sizing guidance in Canada, the proliferation of small interceptors has two results; poor grease removal efficiencies (discharging much higher concentrations of fats, oils and grease than municipal effluent limits), and frequent overflowing (FOG levels far greater than the rated capacity of the GI). The four week maintenance rule clearly targets these under-sized interceptors.
Even the new CSA standard for grease interceptors (CSA Standard B481 Series 12) allows certification of interceptors that will routinely discharge FOG concentrations that exceed municipal effluent limits and the Standard is silent on proper sizing for capacity (ie how large the interceptor should be to retain the daily grease loading and have a reasonable maintenance frequency).
To ensure better removal efficiencies and longer maintenance cycles, some GI manufacturers and progressive plumbing engineers and/or FSEs have specified larger interceptors. There are thousands of larger interceptors in Toronto alone. Depending on the FOG production at the FSE, many larger interceptors will not reach 25% full in four weeks, so that mandated maintenance in four weeks is a waste of money.
To accommodate FSEs with larger interceptors, Toronto Water has provided an exception to the 4-week rule to allow maintenance up to 8 weeks if the FSE can confirm with daily readings that the FOG level does not exceed 25% at any time. Moving the maximum cleaning frequency from four weeks to eight weeks essentially drops annual maintenance costs in half.
Ecoinsight’s FOGWISE™ LT FOG smart meter provides real time FOG level measurements that provide the proof required by regulators to extend the maintenance cycles on larger tanks. The savings gained by doubling the maintenance cycle typically pays for the smart meter in less than two years.