From Environment and Climate Change Canada - Additional Information for the Designation Request of the Erin Wastewater Treatment Plant Project - May 5, 2021

Hi Christine,

Please find ECCC’s responses to your requests below and attached.

Thank you,

Rob Clavering

Senior Environmental Assessment Officer

Environmental Protections Branch – Ontario Region

Environment and Climate Change Canada / Government of Canada

<Email address removed / Tel : <Personal information removed>

Agent supérieur int. d’evaluation environnementale

Direction générale de la protection de l’environnement – Région de l’Ontario

Environnement et Changement climatique Canada / Gouvernement du Canada

<adresse de courriel caviardée> / Tél.: <données d’indentification caviardées>

From: Greenaway, Christine (IAAC/AEIC) <Email address removed>
Sent: April 29, 2021 5:12 PM
To: Clavering, Robert (EC) <Email address removed>
Cc: Plant, Wesley (EC) <Email address removed>; Carriere, Sean (IAAC/AEIC) <Email address removed>; Balsdon, Jeffrey (IAAC/AEIC) <Email address removed>; Weisbrot, Ely (IAAC/AEIC) <Email address removed>
Subject: REQUEST: Expert advice on Erin WWTP DR - by Monday, May 3
Importance: High

Hi Rob,

We have some additional questions about federal and provincial oversight to effluent management for the Erin Wastewater designation request. A response by Monday would be appreciated as we finalize our advice. I am available and happy to get on the phone with technical experts on Friday. 

Understanding that this is a designation request, we may not be able to get all the answers or any further information from the proponent.  What the Agency is seeking is further advice related to water quality impacts, based on the available information, to inform our analysis and advice.

1. The Ontario Ministry of Environment, Conservation and Parks is satisfied that the proponent’s proposed effluent limits meet provincial requirements and are not expected to cause adverse effects on Brook Trout (in the West Credit River).  Can ECCC advise whether it agrees with these conclusions?

1. What can you tell us about how the provincial effluent limits align with federal limits/guidelines, and ECCC’s satisfaction with either? For context, we know that the ECA would set limits for dissolved oxygen and un-ionized ammonia, but not chloride and temperature. However, all treatment plants are required to monitor dissolved oxygen, un-ionized ammonia, chloride and temperature as a condition of the ECA.

Response to Q1 and Q2

ECCC did not comment on the models and projections described in the provincial Class EA and would require additional time to do so.

The proponent and its consultants have conducted a relatively thorough investigation of the potential thermal impacts of effluent discharges as a result of operation of the proposed Erin Wastewater Treatment Plant with a focus on the Brook Trout population in the West Credit River. The Municipal Class EA evaluated potential thermal effects at all life stages for Brook Trout and the study acknowledged that generally the assessment was conservative. For example, a low flow regime scenario was chosen that took into consideration possible further reduction in flows that could occur with climate change. The study concluded that the operation of the Erin Wastewater Treatment Plant would not cause adverse impacts on the Brook Trout population in the West Credit River as a result of the thermal plume downstream from the effluent discharge location. However, there are some uncertainties that remain, as is normal with modelling, for some of the predictions based primarily on modeling for near-field and far-field conditions. Appendix D notes that the study area and downstream to Belfountain contain some of the most productive Brook Trout spawning habitat in the region and ECCC recommends that a focussed follow-up thermal risk study be considered to verify the predictions of the models to ensure that Brook Trout and other important species are protected. Should the proponent proceed with the project and commit to a follow-up program, ECCC would be willing to discuss the follow-up program design in more detail.  

With respect to federal limits, the Wastewater Systems Effluent Regulations (WSER) set national effluent quality standards which are designed to be achieved by a secondary level of wastewater treatment.  The WSER authorise the release of carbonaceous biochemical oxygen demanding matter (CBOD), suspended solids, chlorine, and un-ionized ammonia in the effluents if they meet the effluent standard in the regulations (see below). In addition, regulatees must also meet a number of monitoring and reporting requirements included in the federal regulations.

WSER Effluent Quality Limits

In most cases, provincial effluent limits are stricter than federal limits. Regardless of the provincial limits for this project, the owner/operator is required to meet all requirements of the WSER.

Chlorides are not effluent quality parameters of the WSER. Predicted chloride levels in the effluent described in the Municipal Class EA were developed using data from communities with similar drinking water characteristics to the Town of Erin. Wastewater treatment plant effluent maximum chloride concentrations for these communities were found to be between 274 -713 mg/L.  The Canadian Water Quality Guideline’s (CWQG) long-term concentration for chloride is 120 mg/L.  Although the Town of Erin is proposing to use a membrane bioreactor as part of their treatment system, ECCC understands that low-pressure microfiltration or ultrafiltration will not be able to remove chloride from the wastewater effluent; hence, there could be potential for adverse effects to the receiving environment.

Limits to phosphorus are not included in the WSER. The Environmental Study Report indicated that the proposed wastewater treatment plant would have an effluent phosphorus concentration of 150 µg/L.  It also indicated that the West Credit River is oligotrophic.  According to CCME, the concentration range for total phosphorus for a river with oligotrophic status is between 4-10 µg/L.  Hence, effluent from the wastewater treatment plant with a phosphorus concentration of 150 µg/L could cause potential adverse effects to the receiving environment.

In addition, any releases of deleterious substances that are not authorized under the federal Regulations could be subject to the subsection 36(3) prohibition of the Fisheries Act. Subsection 36(3) prohibits the discharge of deleterious substances in water frequented by fish, unless authorized by a regulation under the Fisheries Act or by regulation under other federal laws. A deleterious substance means:

1. any substance that, if added to any water, would degrade or alter or form part of a process of degradation or alteration of the quality of that water so that it is rendered or is likely to be rendered deleterious to fish or fish habitat or to the use by man of fish that frequent that water, or;
2. any water that contains a substance in such quantity or concentration, or that has been so treated, processed or changed, by heat or other means, from a natural state that it would, if added to any other water, degrade or alter or form part of a process of degradation or alteration of the quality of that water so that it is rendered or is likely to be rendered deleterious to fish or fish habitat or to the use by man of fish that frequent that water.

1. Would ECCC have anything to add or clarify in the excerpt from the Agency’s analysis (see two table entries in ATTACHMENT)? 

Please see additions and clarifications attached.

Also attached are the input received from the proponent, MECP and DFO. The Municipal Class EA ESR is broken into 3 volumes available here: Wastewater Study Documents - Town of Erin | Wastewater (https://wastewater.erin.ca/study_documents).

Thank you,

Christine Greenaway

(she/her|elle)

Team Leader, Ontario Region
Impact Assessment Agency of Canada / Government of Canada
<Email address removed> / Tel: <Personal information removed>

Chef d’équipe, Région de l'Ontario
Agence d'évaluation d'impact du Canada / Gouvernement du Canada
<adresse de courriel caviardée> / Tél. : <données d’indentification caviardées>