The Bureau de normalisation du Québec (BNQ) has launched a 60-day public consultation for its revised guidelines to mitigate risks of inflow and infiltration (I/I) for existing sanitary sewer systems.
The draft standard aims to reduce I/I into existing sanitary sewer systems by exploring data collection and analysis, identification of I/I sources, determination of appropriate levels of service, the development of I/I reduction strategies and an intervention plan, as well as ongoing maintenance practices.
The BNQ says sewer backup is a primary driver of insured loss associated with extreme rainfall events, which continue to increase in intensity and amount of precipitation, boosting the risk of groundwater infiltration for sewer systems. The additional water inflow that must be treated creates significant energy and environmental costs for municipalities, and increases the risk of flooding, according to the BNQ.
“Every year, billions of litres of clean water flow or leak into sanitary sewers in Canada, overloading sewer networks, placing additional burden on wastewater treatment plants, and reducing infrastructure lifespan,” announced Standards Council of Canada’s VP of standardization services, Pierre Bilodeau, in a statement.
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The BNQ notes that the new standard will be an important tool for municipalities to develop I/I strategies as they work to assess risks and prioritize initiatives before investing significant amounts of money in studies and rehabilitation work.
The standard was developed by a committee with experts in data analysis, risk management, asset management, contingency planning, and intervention plan development, as well as representatives from municipalities and sewer system operators.
The draft standard explains the importance of understanding the design and operation of a sanitary sewer system, from which types of sewers are present in their network, to the contribution of different types of flow.
How I/I can affect a municipal system can depend on the age and condition of the sanitary sewer network, as well as its level of maintenance.
The final publication of the new standard is scheduled for summer 2025.
The Bureau de normalisation du Québec released its inflow and infiltration risk mitigation guidelines for new sanitary sewers in 2023.
