Stephen English of the Region of Halton has graciously allowed me to post some of his helpful comments on the details of Ontario's proposal to replace some Permits to Take Water, especially for construction dewatering, with a "permit by rule" exemption under the Environmental Activity and Sector Registry. He doesn't object to the general concept of permit by rule for construction dewatering, but notes that it can have significant impacts on the environment and on municipal sewage systems. These impacts need better controls, which should be added to the Ministry of Environment and Climate Change's plan."Halton has a number of concerns with the proposed operating criteria outlined on pg.15 in the policy proposal:
It should be clarified that groundwater does not fall under the definition of a Liquid Industrial Waste or Hauled Sewage as defined under the Environmental Protection Act (R.R.O. 1990, Regulation 347 General – Waste Management). As such, it is unclear why a "registered waste management system" or "company authorized to haul sewage" would be stipulated under OR-3.1 for the management of construction dewatering.
Halton supports consistent use of nomenclature across Ontario's Regulatory framework, assessment of construction dewatering effluents as Liquid Industrial Waste or Hauled Sewage is in conflict with existing legislative definitions and inconsistent with the nature of uncontaminated groundwater.
2. Construction dewatering water should not go to Sanitary Sewers
Stipulating discharge to a "sanitary" sewer and/or sanitary (wastewater) treatment works is in direct conflict with Section 2.(1).2.(d) of Ontario's Model Sewer Use Bylaw prohibiting the discharge of water "that has originated from a source separate from the water distribution system of the municipality" and is in conflict with industry best management practices (BMPs) and Halton's Sewer Use By-Law (#2-03).
Construction dewatering will tend to increase during wet weather, due to surface run-off and water table fluctuations, increasing hydraulic stress of the sanitary sewer during peak flow periods and contributing to flooding and overflow risks as the sanitary sewage system is not designed to convey groundwater takings.
Further, the sensitive biological systems of a sewage treatment works are not designed to treat naturally mineralized groundwater and/or anthropogenic contaminants likely to be present therein, the efficacy of this approach is uncertain and the risk of a process upset should not be underestimated.
For a planned discharge to a sanitary sewer and/or sewage treatment plants written authorizations in accordance with the applicable municipal by-laws (e.g. municipal (sanitary) sewer use approval) should be identified as eligibility requirement within the regulation enabling EASR-eligibility for short term water takings.
3. Storm Sewers
Storm sewers (including ditches) and stormwater management facilities are absent from the list under OR-3.1. It is our understanding that the optimum hydrological solution is to return the water as close to the taking as possible, and that other than a direct discharge to the natural environment, discharge to the storm sewer infrastructure systems provides the best outlet for uncontaminated groundwater.
For a planned discharge to a storm sewer and/or storm water management works written authorizations in accordance with the municipal by-laws (e.g. municipal (storm) sewer use approval) should be identified as eligibility requirement within the regulation enabling EASR-eligibility for short term water takings.
4. Discharge Filtration and Treatment
Under OR-3.2 a Qualified Professional should be directed to identify necessary treatment technology for uncontaminated groundwater prior to direct discharge to the natural environment and/or storm sewers, rather than encouraged to pursue practices prohibited by Ontario's Model Sewer Use By-Law.
A wide array of discharge filtration and treatment equipment is
commercially available (some with ECA approvals) in Ontario to
support construction dewatering activities, including receiving
tanks Baffle/Weir Tanks, and treatment steps Media Filters,
Oil/Water Separators, and Sediment Traps/Filters, which can be used
alone or in series to address quality control prior to discharge
and/or in conjunction with site-wide management practices including
the use of check dams and swales.
Halton supports the use of source controls to manage construction dewatering activities, to achieve the necessary environmental protection with the least disruption to the quantity of water within a sub-watershed.
5. Environmental Quality Guidelines
The Canadian Environmental Quality Guidelines (CEQG) establishes discrete narrative standards for both TSS and Turbidity in relation to in-water quality. The CEQG have limited legal effect in Ontario except through adoption within the Provincial Water Quality Objectives (PWQO). Application of the CEQG would require extensive receiver assessment and monitoring, in addition to the quantification of construction dewatering discharge. Reference to the CEQG for Turbidity (OR-3.3) is onerous (receiver assessment) and is inconsistent with the current standard terms & conditions related to discharge to the natural environment.
The PWQO includes an in-water quality standard for Turbidity (Table 2, pg. 27), and general narrative standards related to TSS (Table 1), historically the MOECC has specified a TSS limit of 25 mg/L for discharges to surface water within approved Permit to Take Water terms and conditions.
Halton would support a 25 mg/L TSS target within the eligibility criterion for discharge to the natural environment within the regulation enabling EASR-eligibility for short term water takings."
Thank you, Stephen, for allowing me to post these very helpful comments.
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