Painting the Full Picture—Condition Assessments Upgraded to Comprehensive Asset Evaluations

As Wastewater Resource Recovery Facilities (WRRFs) encounter critical decisions on how to deal with aging infrastructure and future regulations, condition assessment inspections provide valuable estimates on the remaining useful life (RUL) of individual assets. There are however many driverswhich can exist for replacing an asset ahead of its condition-based RUL—including safety during operations/maintenance, impending regulatory requirements, capacity, and availability of spare parts This paper will detail the comprehensive asset evaluation (CAE) process developed to assign a RULs for the capacity, regulatory, and sustainability/optimization drivers through a consensusbuilding effort with engineering, operations, and maintenance plant staff. The primary goal of the CAE process is to fast track optimization efforts (especially for assets with significant RUL based on condition assessments), identify opportunities to extend RUL, and systematically identify asset/systems that need to be replaced as part of short term, near term, and long term capital projects. The CAE process also aims to yield simple and easy-to-communicate timelines from difficult to define drivers (i.e. sustainability/optimization). For this case study, CAEs were completed for Central Contra Costa Sanitary District (Central San) steam, secondary process, and electrical assets as part of the Energy Systems and Aeration Systems Upgrades Project (Steam Project).