Case Study: King County WTD – South Treatment Plant

Decrease energy consumption, noise level, heat generation, and maintenance costs

Project Background
Increasing energy efficiency is a top priority at King County, so it wasn’t difficult to find an opportunity when it came to their existing multistage centrifugal (MSC) blowers at their South Plant facility. With the support of Puget Sound Energy and the Washington State Public Works Board, the South Treatment Plant was able to secure $331,785 in incentives and $668,215 in a low interest loan towards the retrofit of their agitation air blowers.

Driving the project with energy efficiency in mind, King County also identified various operational and maintenance improvements that were needed, which included improving the working conditions of plant staff, increasing operational reliability, and reducing on-going scheduled maintenance expenses. According to King County, the existing blowers were “noisy, hot, and costly to operate and maintain.”

APG-Neuros provided a solution to meet these challenges with the support of their knowledgeable engineering team and with their innovative NX Series turbo blowers. A significant benefit in this retrofit is that the capacity of two NX200 blowers equals the capacity of three centrifugal blowers, thus reducing the equipment quantity and footprint. The collaborative efforts between APG-Neuros and King County, in addition to the highly effective internal organization within the county, resulted in a seamless and successful project.
King County estimates the two new blowers will save $55,000 in annual energy costs and reduce South Treatment Plant’s energy consumption by 782,268 kilowatt-hours (kWh) per year- the equivalent of powering 45 homes!

In December 2013, almost a year after the new APG-Neuros turbo blowers were received, King County WTD celebrated the official completion of the project. The celebration recognized PSE for their financial contributions to support the project, recognition of King county staff who made the project possible, and the inventiveness of the APG-Neuros turbo blower to help them achieve their goals of energy efficiency.

Payback Analysis
Equipment Payback Period- Taxed equipment cost/proposed energy savings: $331,785/$55,000 = 6 years
Project Payback Period – (construction cost + taxed equipment cost – incentives)/proposed energy savings: ($668,215 + $331,785 – $331,785)/$55,000 – 12 years