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Community Information Bulletins/Additional Information on CNL’s Response to Non-Compliance in Sewage Effluent
May 03, 2024

Additional Information on CNL’s Response to Non-Compliance in Sewage Effluent

CNL’s Sanitary Sewage Treatment Facility (SSTF) is a new (2019) and very modern sewage plant that uses leading-edge, environmentally friendly technologies to process sewage. It has operated safely for several years. This is the same kind of plant that you will see in towns and cities in Canada for sewage treatment and serves the more than 3,000 employees and contractors at the CRL site.

Several weeks ago, CNL launched a significant effort to recover our Sanitary Sewage Treatment Facility (SSTF) to compliant operations following an upset condition. The upset condition affected the biological treatment process in use at the sewage treatment plant.  This takes some time to recover from, as the biological population needs to rebuild to a culture that has the appropriate age and type of micro-fauna. Other than this non-compliance of sewage discharge, the facility continues to meet all regulatory requirements.

We have a dedicated team, supported by external experts, working to identify the source of any operational discharges which may have contributed to the upset conditions in the plant. The current focus of the investigation is on detergents or cleaning solutions used within the laboratories.

The discharge from the sewage treatment facility does not pose a threat to the environment or the public.  CNL can also confirm that this non-compliance is not related to radiological contaminants.

The health of the micro-fauna has been improving and CNL is beginning to see positive progress. To declare that the SSTF has returned to consistent normal operation requires another month of positive test results.

CNL maintains a rigorous public information program that includes public and Indigenous access to information related to routine emissions, and non-routine items or events at Chalk River Laboratories. Local officials, key stakeholders and Indigenous communities were notified through direct contact at the time that events were reported on our external website.  CNL is also providing bi-weekly progress reports to Environment and Climate Change Canada until the issue is resolved.

For more information on CNL’s environmental program, including our performance reporting, please visit


Philip Kompass
Director, Corporate Communications
[email protected]