Priorisation of wastewater pump station upgrades using asset management practice
Annual Conference
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Christchurch City Council (CCC), has many pump stations (PStns) across the sewerage network.
The project objective was to use a Whole Life Cycle Assessment (WLCA) model as an investment decision tool to justify the replacement of the old long life pumps with more efficient modern technology pumps.
This paper describes how we worked with CCC’s existing asset data, combined with expertise in PStn design and engineering, to devise a strategic prioritisation programme of PStn upgrades for input to the 2009-19 Long Term Council Community Plan (LTCCP).
The initial analysis was based on five PStns which CCC recognised required upgrade, due to high maintenance costs caused by asset dilapidation or insufficient capacity. We developed a series of standard concept upgrade designs and capital cost (CAPEX) estimates, adopting CCCs preferred pump technology and design standard that was then applied to each PStn.
The target payback period was between 5 and 7 years. Unfortunately, the predicted payback periods were significantly greater and generally as long as the residual life of each PStn, meaning WCLA alone could not be utilised to set priorities.
Therefore, in conjunction with CCC, we developed priorities based on PStn issues such as asset renewal date, high maintenance costs, high pump run hours and pump technology replacement. These were then extrapolated across all CCC PStns and the priorities set. We used the original standard upgrade options developed to assess the best upgrade option for each PStn and therefore the LTCCP cost.