High energy consumption and limited and inefficient operation

LOTT Alliance secured a Puget Sound Energy (PSE) grant to replace its existing Positive Displacement blowers with Dual Core High Efficiency APG-Neuros turbo blowers which resulted in 100 HP power reductions and savings of around 300 HP based on the plant’s average operation.

Challenge
The LOTT Alliance, Budd Inlet Treatment Plant was faced with high energy consumption and limited and inefficient operation of its existing Positive Displacement (P.D.) blowers used for an Aeration Process. The aeration system at the plant had four, 500 horsepower P.D. Roots blowers which could only run at constant speed. As a result, the plant operators were not able to turn down the blowers to meet the minimum and average air flow requirements, resulting in production of more air than was needed. To avoid over aerating the basins, they had to blow off excess air into a train of clean water (one million gallons).

Solution
In 2010, the Washington State Department of General Administration issued an Energy Performance Contract to Trane Climate Solutions to procure services to design and install a new cogeneration system and an aeration blower retrofit at the Budd Inlet Facility for the Lott Clean Water Alliance. For the new system design, the engineers wanted to look at a more efficient blower option that would be able to achieve the required turndown that meets the plant’s full range of demand levels.

The new renewable energy system, combined with an aeration blower at the Budd Inlet Treatment Plant, were expected to result in a reduction of more than 2.8 million kilowatt hours (kWh) per year, which would signify savings of more than $228,000 per year in utility costs. Thanks to the potential energy savings, the aeration blower upgrade was qualified for a Puget Sound Energy (PSE) grant which was estimated at more than $300,000, representing 70% of the total project cost. The grant would pay for the blower equipment, leaving the remainder of the funds to be applied towards other upgrades associated with the blower retrofit.
With the grant funds, one of the four existing Roots PD blowers was replaced with the APG-Neuros High Efficiency Turbo Blower – a Dual Core NX400-C100 model. The three remaining PD blowers were kept on stand-by to meet potential future demand. The APG-Neuros blower is now the primary operating unit, providing approximately 95% of the plant’s aeration system needs. The innovative Dual Core blower is composed of two 200 HP motors within the same enclosure, allowing the blower to achieve both their minimum and maximum air flows of 1,300 and 6,000 SCFM respectively thanks to its high turndown rate of 75%. The Engineering Director at Lott Alliance, Brian Topolski, noted that typically one 200 HP core of the Dual Core unit is all that is needed to meet the plant’s average flows. By selecting the Dual Core model, the blower retrofit resulted in 100 HP power reduction, with savings of around 300 HP based on their average operation.

Positive Results
This retrofit design allowed the plant to increase the overall aeration system efficiency and reduce the annual blower-related expenses. The project was expected to save more than $48,000 annually in utility costs and maintenance costs for the LOTT Alliance.
Because of their commitment to environmental responsibility and the wastewater treatment process optimization, leaders at the LOTT Alliance received the Trane “Energy Efficiency Leader Award” for their sustainable energy and operational efficiency improvements.