Sewage Works Reports

Annual Performance Report Overview

Sections of the following report(s) correspond with Schedule E (4.6) of ECA No. 245-W601 and Condition 9 (5) of Certificate of Approval No. 1604-5RPQY4.

Overall 2025 Performance Report Summary

The plant consistently operates well within the effluent objectives/limits as set out in the Certificate of Approval.

Summary of 2025 Monitoring Data

ECA No. 245-W601 – Schedule E 4.6.3 and Certificate of Approval No. 1604-5RPQY4 – SECTION 9 (5.a.) require a summary of all required monitoring data along with an interpretation of the data and any conclusions drawn from the data evaluation about the need for future modifications to the Authorized System or system operations.

2025 Sewage Treatment Plant Performance
Parameter	Effluent Limits*	Effluent Objectives**	2025 Results	Comments
CBOD 5	30.0 mg/L	20.0 mg/L	Annual Average: 3.0 mg/L	Average annual concentration does not exceed 30 mg/L
Total Suspended Solids	30.0 mg/L	20.0 mg/L	Annual Average: 2.0 mg/L	Average annual concentration does not exceed 30 mg/L
Hydrogen Sulphide	0.08 mg/L (water temp >10 degrees Celsius) 0.10 mg/L (water temp <10 degrees Celsius)	0.08 mg/L (water temp >10 degrees Celsius) 0.10 mg/L (water temp <10 degrees Celsius)	Annual Average: 0.02 mg/L	Average monthly concentrations did not exceed limits.
Ammonia Nitrogen	13.0 mg/L (April–October) 30.0 mg/L (November–March)	10.0 mg/L (April–October) 20.0 mg/L (November–March)	April–October: 0.33 mg/L November–March: 4.84 mg/L	Average monthly concentrations did not exceed limits.
Phosphorous	0.5 mg/L 158.9 kg/year	0.3 mg/L	Annual Average: 0.04 mg/L Annual Average Loading: 5.78 kg/year	Average monthly concentrations and annual average loading do not exceed limits.
pH	6.0 – 9.5	(Owner shall use best efforts to maintain) 6.5 – 9.0	Annual Range: 6.45 – 9.37	Annual pH range exceeded effluent limits during no effluent events. When grab sample collected pH at 9.60 on May 12, 2025 the gate valve was shutoff immediately and no wastewater was released into Mink Creek.
E coli	N/A	Monthly Geometric Mean Density of 200 organisms/100mL	384.91 organisms/100mL	Geometric Mean Density determined using method stipulated in Certificate of Approval.

* As outlined in condition 6.
** As outlined in condition 5.

2025 Flow and Capacity Summaries

The Certificate of Approval lists the system as having a Rated Capacity of 843 cubic metres per day.
The 2025 influent average daily flow over the 12-month period was 736 cubic metres.
Average daily effluent flow over the 12-month period was 229 cubic metres.

Frequent Daily Flow Exceedance

High flows entering the Cardiff Sewage Lagoons are suspected to be associated with weather events such as heavy rain and spring run-off. Basement drains are connected to the sanitary sewer system and likely contribute to elevated flows entering the lagoons. Although the Cardiff Lagoons often approach or exceed the rated capacity, effluent limits are achieved, and objectives are ordinarily reached.

Additional Reporting Criteria

4.6.4, 5.b.: Description of any operating problems encountered, and corrective actions taken.

The influent flowmeter at Cardiff Sewage pumping station had some issues with low signal and frequency bouncing, which was resolved by the instrumentation technician.

4.6.5, 5.c., 5.e.: Summary of all maintenance, repairs, and calibration carried out on any major structure, equipment, apparatus, mechanism, or thing forming a part of the works.

Effluent and raw flow meters calibrated on October 9, 2025.
New lateral sewer connection was done at 5 Short St., Cardiff on November 6, 2025.
The raw flow meter sensor was relocated in the wet well at Cardiff Sewer Plant on November 14, 2025.

5.d.: Summary of any effluent quality assurance or control measures undertaken during the period January 1, 2025 to December 31, 2025.

All raw sewage and effluent samples collected as required under Certificate of Approval #1604-5RPQY4. Daily records maintained, procedures and policies in place to ensure compliance. Routine monitoring of raw and effluent flows throughout 2025.

5.f.: Description of efforts made, and results achieved in meeting the Effluent Objectives of Condition 5.

“Rated Capacity” (843m3/day) has been exceeded on individual days throughout the year. Exploring options/timelines to undertake inflow and infiltration studies in the collection system to determine areas of impact to the collection system.

5.g.: Tabulation of the volume of sludge generated in the reporting period and an outline of anticipated volumes to be generated in the next reporting period and a summary of the locations to where the sludge was disposed.

Sludge volume testing was completed in 2022 for all 3 lagoon cells. Sludge removal project being investigated for future development.

4.6.6, 5.h.: Summary of any complaints received during the reporting period and any steps taken to address the complaints.

No complaints received throughout 2025.

4.6.7: Summary of all Alterations to the Authorized System within the reporting period that are authorized by this Approval including a list of Alterations that pose a Significant Drinking Water Threat.

None.

4.6.8: Summary of all Collection System Overflow(s) and Spill(s) of Sewage.

None.

4.6.9: Summary of efforts made to reduce Collection System Overflows, Spills, STP Overflows, and/or STP Bypasses.

None.

5.i.: Summary of all bypasses, spills, or abnormal discharge events.

Bypassed flow meter and alum addition for approximately 5 days between Wednesday April 2 to Monday April 7, 2025. Used external diesel pump removing from wet well to keep up with flow and discharging into old force main directly into cell #2 at the lagoon. No discharge to natural environment or water body.

5.j.: Summary of any other information the District Manager requires from time to time.

None.

Additional Information

Comprehensive interpretation of all monitoring and analytical data obtained during the reporting period and a comparison to the effluent quality and quantity criteria.

See above Sewage Treatment Plant Performance and associated summaries for the period January through December 2025.

Alterations, extensions or replacements in the process or operations of the works which are considered for implementation over the next reporting period, especially those which may require approval under the Ontario Water Resources Act.

None.

A summary of the locations where the sludge disposal areas are to be utilized and sludge handling methods over the next reporting period.

Sludge removal being considered for 2026 if necessary. MECP would be contacted to consult before proceeding and determine an appropriate disposal area that could be utilized.