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OPTIMIZED STEWARDSHIP Planned vs. Reactive Spending

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As an industry Optimized Stewardship of our assets will be obtained by making maintenance best practices a part of our culture. To succeed in this endeavor we need to make investments now that will secure a reasonable chance of success. Implicit in the term “Optimized Stewardship” is the premise that we are placed in a position of trust by our communities to care for the investment they have made in their collections and treatment systems. Our role as stewards is not to bury our “minas” and forget about them but, to actively find ways to maximize a return on their investment. As actual “real life” examples of the benefits of planned maintenance are showcased, a greater degree of buy in will be the natural result.

This paper is a presentation of one such example. It is a short story of a major emergency repair confounded by stereotypical but real unexpected troubles and expenses. Often is the time that many consultants and maintenance professionals tout the savings and reliability gains associated with planned maintenance but seldom are we actually witnesses to this reality. In the telling of this story we see a major decline in reliability and a huge expenditure juxtaposed with a simple plan that includes actual known expenses of this highly predictable failure. The cost of executing this repair in the “heat of battle” was over 2 times the cost as if it were planned. In addition the overall reliability is dramatically increased through managed replacements.

The “Case Study” at hand concerns lift stations at the Washington Suburban Sanitary Commission's (WSSC) Piscataway wastewater treatment plant. These lift stations employ 30mgd Archimedes screw lift pumps. It demonstrates how planned replacement of critical components is considerably more cost effective and greatly improves future reliability. Also included, by way of conclusion is a 15 year schedule of planed replacements beginning in 2008. This schedule was the result of our awakening to the objective reality, that there are real and material benefits to planned maintenance.

The data presented will compare replacement strategies over two 15 year periods. The actual replacement costs in “emergency mode” 3 screws in 2006–07 plus the repeated emergency mode repair of the original screws at age 15 in 2022. In contrast to the replacement, in “planned mode” (based on maximizing reliability) of 7 screws at two different stations over the same time period. The result is that 7 of these nearly 125,000 elements can be replaced for less than the cost of five. All the while greatly increasing reliability and normalizing spending over this 15 year period.

Document Type: Research Article


Publication date: 2007-01-01

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  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

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