Pump stations are key control points in a wastewater utility’s infrastructure assets. An audit can help identify performance and maintenance issues, in addition to deterioration of asset condition which may cause system failure. This presentation includes a discussion of the value, technical aspects and protocol for performing pump station audits, as well benefits and lessons learned through completed projects.
Concerns related to pump stations generally focus on nuisance (odor control), public health, potential sanitary sewer overflows, maintenance and capital costs as well as related problems downstream. Audits offer an opportunity to identify and proactively mitigate issues, prolong the lifespan of the wastewater facilities, and support long-term asset management strategies.
An audit should include six key steps:
- Operations and maintenance staff interviews – helps identify chronic issues and concerns. O&M staff offer valuable insight and historical knowledge of each facility.
- Pump performance analysis – compares pressure, condition and flow versus expected performance. Drawdown tests combined with pressure gauge results and instrument measurements are used to analyze operations.
- Condition assessment – documents corrosion in various equipment, systems and piping. Risk of structural failure should be documented.
- Site evaluation – assesses access and turnaround capabilities, drainage, and lighting.
- Electrical and instrumentation – determines reliability of primary and secondary power, proper operation of alarms and instruments, and potential electrical issues.
- Safety and odor assessment – measures level of hydrogen sulfide and documents any safety concerns including risk of falls, security and exposed moving parts.
Following the audit, a report is developed to outline existing assets and any problems identified. A range of rehabilitation along with preliminary cost estimates may be presented. Recommendations might include cleaning, pump replacements or structural rehabilitations. Likelihood versus consequence of failure should be discussed in detail to help owners prioritize any needed repairs.
Case studies with associated findings and lessons learned were presented for four pump station audits. The different scenarios resulted in a host of benefits including reduced pump times and clogging, cost savings, improved standards, reduction in pump failure and alarms, and elimination of a development approval process roadblock.
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