Dairy Processor Upgrades to VSD Technology for Maximum Energy Savings
Got milk? For a New England-based dairy processor, producing two million gallons of milk per week requires a sophisticated operation that runs smoothly and efficiently. Operating since 1931, the company processes raw milk from more than 1,000 local farms and turns it into the skim, 1% and 2% milk available at the grocery store.
The Dairy Industry and Wastewater Treatment
Some processes involved in making dairy products create wastewater, which has to be treated in the dairy processor’s wastewater facility. The treatment process starts in a 4,500,000 gallon bulk volume fermenter tank where a membrane separates liquid from milk fats, milk solids and organic solids which are digested by anaerobic bacteria. The secondary treatment process takes place in a re-aeration tank, where fine bubbles are injected into the water. These bubbles transfer oxygen to the process and help the aerobic bacteria produce enzymes that further break down the waste.
While fine bubble aeration is the most sustainable, energy efficient approach to wastewater aeration, it requires a steady stream of low pressure air, which often represents the largest operating cost component for the aeration process. When the company decided to replace the tank membranes in their onsite wastewater treatment facility, they also realized the increased membrane capacity would require a higher volume of compressed air.
Initially, the dairy processor considered just modifying their current compressed air system to meet the increased demand for flow capacity. The options were to add an additional lobe blower, or replace the blowers with a larger lobe blower that would satisfy the entire demand. But because the noise level would dramatically increase and the system would still operate less efficiently, the company decided to consult with an engineering firm and Atlas Copco for advice on the project.
The solution? Because the effluent output varied, resulting in a different compressed air requirement at different load points, variable speed drive technology was recommended for the project. An Atlas Copco ZS+ 75 oil-free rotary screw blower with variable speed drive was selected to meet both the flow and the pressure requirements. The ZS also features low sound levels, around 72 dB(A), which substantially reduced the noise levels in comparison to the lobe blower option.
Check back on the Fifth Utility Blog next week to learn how the dairy processor financed the project through a utility incentive program and reduced the original projected payback time by approximately five months. If you’d like to learn more about Atlas Copco rotary screw technology, or creative ways to finance an upgrade project, check out the following articles or simply contact us by completing the below form.
Atlas Copco Compressors LLC is part of the Compressor Technique Business Area, and its headquarters are located in Rock Hill, S.C. The company manufactures, markets, and services oil-free and oil-injected stationary air compressors, air treatment equipment, and air management systems, including local manufacturing of select products. The Atlas Copco Group, which celebrated its 140th anniversary in 2013, is among the Top 100 sustainable companies in the world and a member of the Dow Jones World Sustainability Index. Atlas Copco has also been recognized by Forbes, Thomson-Reuters and Newsweek, among others, for its commitment to innovation and sustainability. Atlas Copco Compressors has major sales, manufacturing, production, and distribution facilities located in California, Illinois, Massachusetts, North Carolina, South Carolina, and Texas