Plant operators in the water and wastewater treatment industry are searching for ways to strategically manage energy usage and increase efficiency. In a recent Q&A with industry publication Water Online, Magnetrol® global product manager Tom Kemme discussed energy management solutions for treatment plants. Below are some of his thoughts on the need for energy management today and how it creates cost savings for treatment plants.
Why do you think customers are eager for energy management solutions at this time?
I think that the biggest reason for energy management projects is the ROI [return on investment]. There are many efficiencies that can be gained for aeration monitoring, but many wastewater facilities now are not just burning off methane from anaerobic digesters — known as flaring — but renewing it.
They may use the methane as fuel for a boiler that is providing hot water or steam to the plant, or even as a fuel in an energy generation project to produce electricity. With their own on-site electricity generation, it may save the plant hundreds of thousands of dollars per year. Sometimes these “green” initiatives have a negative connotation, but they can really make a business case depending on the amount of biogas being generated. Thermal mass flow meters have no moving parts and can measure flow at very low pressures, increasing the replacement rate of older flow technologies such as positive displacement type meters.
How much can a plant save on its bottom line with proper flow measurement and energy management?
Monitoring cost savings from aeration projects seems to be more common than energy management projects involving full utilization of biogas produced from anaerobic digestion, but this number is also growing. For example, one of the smaller plants that we worked with has an average capacity of around 10 MGD and was saving an estimated $100,000 per year by using its biogas to generate electricity. It also provides security from interruptions in natural gas and electricity grids.
When choosing a flow technology, thermal mass is a successful mixture of performance and economics. This is especially true if you look at the life of the flow meter with maintenance costs associated with it. Many manufacturers now have calibration verification procedures that can be run at the plant to prevent unnecessary downtime and recalibration costs. Make sure the meter has a calibration verification option and calculate the costs of performing the procedure along with the initial purchase price. Recalibration costs can easily reach $1,000 each and take multiple weeks for turnaround.