Inflow and Infiltration Reduction and Pump Station Renewals
Indigenous Services Canada (ISC) retained Kerr Wood Leidal (KWL) to complete inflow and infiltration reduction detailed design and sewer lift station preliminary design services. This would assist the Nation in reducing water pollution, minimize operation and maintenance costs, meet current safety codes at the sewer lift station, reduce the likelihood of sewer backups, and reduce CRD sewage charges. Esquimalt Nation's Director of Lands and Infrastructure is overseeing the project activities, which will resume in the fall of 2019.
The mechanical and electrical components of the Kosapsum Crescent Sewer Lift Station are recommended for replacement. The station is 27 years old and would benefit from a mechanical and electrical upgrade for the following reasons, listed in order of priority:
- The station has no alarms for high water level or component failures;
- The station is not equipped with a backup power generator;
- Gases from the wetwell can access the electrical kiosk which is a safety code compliance issue;
- The pumps motors have a higher risk of failure given their age;
- The electrical kiosk components have a higher risk of failure given their age. Some replacement parts may be difficult to source given their age;
- The station has a large control volume with no sloping side walls to direct solids and floating debris towards the pumps. This causes grease and debris buildup in the wetwell and the need for frequent vactor cleaning.
- Check valves, located in the wetwell, cannot be easily accessed for maintenance or replacement. The personnel access hatch and ladder are on the opposite wall making it difficult to maintenance the check valves;
- Steel piping, valves, and roof structure have moderate rust degradation which will increase in the future;
Conclusions and Recommendations
The following conclusions are made:
- Buildup of concrete in the sewer infrastructure needs to be removed. The sewer connection to the TRIO wash out facility should be abandoned to prevent dumping of concrete and concrete wash water from occurring in the future.
- Older infrastructure in the TRIO yard should be abandoned and new laterals installed for Lot 7 and the Trio Works yard as this system is full of concrete. This action will remove land encumbrances for future development.
The recommended pump station upgrades will:
- Reduce the risk and likelihood of flooding due to lift station failure;
- Make operation and maintenance easier and less costly.