Not All Diffused Aeration Systems Are Created Equal

Not Equal

Diffused aeration systems used in municipal water treatment facilities are a little bit like cars – they are not all equal – in price, performance or reliability. An inexpensive Ford Fiesta is certainly not the same as a Honda Accord, despite the fact they can both get you from point A to B. Many people choose Hondas because of their long track record of reliability and low maintenance costs.

Reliability is more important than the lowest price because the consumer wants a vehicle that is built to last a long time – at least as long as the length of the loan he or she took out to purchase it. This scenario is very similar to specifying equipment for wastewater treatment facility designs.

Design engineers of major wastewater treatment projects usually practice a procurement format where they specify the best available technology and best life cycle cost. They consider multiple criteria when doing product research, including best available technology, experience, quality, service and life cycle costs.

It specifies the basis of design manufacturer, models and configurations that are acceptable. This assures the project owners that the objectives the design engineer had in mind when he or she designed the plant will be preserved when the contractor purchases the equipment.

Ambiguous specifications force contractors to use “or equal” or named products which do not meet the specifications. This tends to result in numerous exceptions and clarifications which must be resolved after procuring equipment. The owner may end up with a “Ford Fiesta-like” system that doesn’t deliver the performance and life cycle costs they were promised with a reliable “Honda Accord-like” treatment system. In addition, the process of submitting products with numerous exceptions and clarifications can slow the approval process down considerably.

Diffused aeration systems are on the procurement bubble

Value-based procurement is critical for all major unit processes in a wastewater treatment system. Unfortunately, diffused aeration systems are losing the distinction of being a major unit process. That means they’re being relegated to “or equal” status, which enables contractors to consider other suppliers and substitutes/alternates, often with less than desirable results.

No two diffused aeration systems are created equal. Naming multiple suppliers without thoroughly identifying the significant differences between each system results in numerous exceptions/clarifications before and after the bid. In addition, a factor that may have been taken into consideration for the system evaluated as the basis of design and best life cycle cost may not be attainable by all named bidders.

Value-based procurement encourages major equipment submissions to state reviewing and funding agencies to identify the manufacturer named as the basis of design, as well as specifications reflecting the design utilized in the life cycle cost evaluation.

Adopt this win/win approach

The basis of bid/basis of award procurement method provides a win/win for all participants:

  • Major systems equipment selection by the owner and engineer are based on best available technology, experience, quality, service and life cycle cost rather than by the contractor, based on lowest capital cost.
  • The project owner is not forced into accepting a lower capital cost and higher life cycle cost system, which will cause significantly higher costs over the life of the wastewater treatment plant.
  • The engineer is not forced into accepting lower quality equipment that may not last for the duration of the loan or which must be supported by the multiple named or “or equal” suppliers.
  • Multiple named “or equal” suppliers are not forced into providing equipment that they do not manufacture and cannot support.

Most importantly, the contractor is not forced into making decisions that should really be made by the design engineer and plant owner.

It’s time to take action

If you are a plant owner (who ultimately pays the loans on it), you need to insist that all major equipment purchases for your project passes the litmus test of best available technology and best life cycle cost. The result is a clearly defined design basis which offers the best life cycle cost – and fewer nasty surprises for you.

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