Most electric utilities offer customer incentives for implementing energy conservation measures (ECMs) Incentive programs pay customers to use less energy. In some cases they are mandated by legislation and in others the incentives are driven by the utility’s desire to avoid building new generating capacity. Some incentives are based on reduced energy use (kWh) and some are based on lower peak demand (kW).
Sizing, selection, and adjusting control valves often causes confusion for process and control system designers. Improper valve application can cause operating problems for plant staff and waste blower power. Basing the airflow control system design on fundamental principles will improve valve and control system performance.
When the plant’s original aeration blowers became costly to operate and newer technology offered the promise of energy-savings, Fuqua took decisive action and replaced the older blowers with high-speed turbo blowers. As a result, the plant saves ratepayers approximately $30,000 per year in energy costs and bolsters the plant’s ability to maintain uptime and achieve extremely clean effluent.
One need look no further than the treatment plant’s digester project upgrade to see the value of the plant’s forward-thinking approach at work. The upgrade involved the replacement of five Positive Displacement (PD) blowers with four, high-speed Inovair integrally geared blowers for aerating the digesters. With fewer – and smaller – blowers the plant saves tens of thousands of dollars in energy costs per year. The blowers also offer flexibility to cost-effectively adapt to the need for increased water treatment in the future.
Aeration blower upgrades may be part of a total plant upgrade and minimizing energy consumption is a critical consideration. Blower replacements are also a common Energy Conservation Measure (ECM) in cost-reduction programs.
Julie Gass, P.E., is a Lead Mechanical Process Engineer at Black & Veatch and an industry veteran with extensive experience in mechanical equipment in wastewater treatment plants. She also served on the American Society of Mechanical Engineers (ASME) Committee responsible for ASME PTC 13, Wire-to-Air Performance Test Code for Blower Systems, which is the performance test code published in October 2019 for all blower technologies. Blower & Vacuum Best Practices Magazine interviewed Gass to gain her views on aeration blowers, PTC 13, and the firm’s rigorous specification process to ensure treatment plants get the blower best suited for their application.
Finally, a test code has been created that will provide accurate performance comparisons for both positive displacement and dynamic (centrifugal) blowers. ASME PTC 13 provides procedures for determining the required total operating electrical power of a packaged blower system, termed the “wire-to-air” performance. Here’s a review of PTC 13 and considerations related to this important standard.
The 2019 WEFTEC Technical Exhibition and Conference was held September 23-25 at McCormick Place in Chicago. The event featured 148 technical sessions, 27 workshops, 16 mobile sessions, seven local facility tours and 1,000+ exhibitors. Both Blower & Vacuum Best Practices and Compressed Air Best Practices® Magazines were pleased to be in the literature bins at the 2019 WEFTEC!
In the first of this two-part series on the basics of aeration control valves we examined valve fundamentals and basic equations for analysis. Here, we look at interactions between valves and discuss new flow control technologies.
Efficiency compares the inputs used by a system to the outputs produced. It is a commonly used concept, but one which is prone to a great deal of misuse in many industries. This article provides insight into the parameter known as “efficiency,” how it’s calculated, and importantly, it’s uses and limitations in predicting blower energy consumption and comparing alternate system designs.
After auditing and field-testing, the Sni-A-Bar Municipal Wastewater Plant in Blue Springs, Missouri, partnered with Inovair to replace 4 fixed-speed rotary lobe blowers on its aeration system with 4 Variable Frequency Drive (VFD), integrally geared centrifugal blowers. The new blowers, along with improvements in blower controls, reduces annual energy use by 442,664 kWh and peak electrical demand by 48.76 kW, which translates to an annual energy reduction of 37 percent and anticipated savings of $42,000 per year. Additionally, a rebate of $45,799 from the local utility resulted in a payback of less than six years.