Acoustic panels reduce the roar at a solids dewatering plant
Absorbing the noise
The Albuquerque Bernalillo County Water Utility Authority in Albuquerque, New Mexico operates a 76-million gallons per day (rated capacity) wastewater treatment plant that treats a daily average of five million gallons of sewage from New Mexico’s largest city and its surroundings.
One of the operations in the wastewater treatment process is the dewatering of the sludge stream produced after aerobic digestion. This separation occurs in the centrifuge room, where three continuous Alfa Laval G-2 Dewatering Centrifuges handle the task. The cake that comes off the centrifuges is mixed with green solids and sent to composting, while the liquor is rerouted to the intake of the wastewater treatment process.
A recent renovation of the centrifuge room included a call for upgrading the existing noise remediation treatment.
The centrifuges create quite a racket. Each centrifuge is a 400 gpm unit powered by a 200 horsepower motor operating at 2600 rpm. The room also presents an acoustic challenge: it is 86 feet long by 36 feet wide and 17 feet high. The floor, walls and ceiling are concrete — hard surfaces that promote excessive sound reverberation.
The existing acoustic treatment, which consisted of perforated concrete blocks and acoustic foam blown on the ceiling, was clearly inadequate, making verbal communication within the room extremely difficult and creating a safety hazard.
According to Jesse May, project manager for the construction firm that performed the renovation, acoustic panels were specified for the job. The specifics called for 85 percent sound absorption with panels covering 100 percent of the available ceiling space, and 100 percent of the wall space from 11 feet, 4 inches above the floor up to the ceiling on three walls. The fourth wall opens to other parts of the plant.
The installation consists of 159 aluminum acoustic panels. Forty-five 30 in. x 48 in. panels were installed on the walls with the remaining 114 panels installed on the ceiling, ranging in size from 30 in. x 96 in. down to 12 in. x 18 in. to fit around lights, ceiling beams and skylights. Paint color was Sherwin Williams Dover White.
Installation, which was performed by Archer Western, was straightforward and proceeded without a hitch, said May. The panels were easily attached to the ceiling and to the concrete walls with four stainless steel mounting bolts.
Installation of the panels has made a noticeable difference in the room’s reverberation rate, and thus the acoustic ambience of the room. Acoustic tests reveal a 12 dB drop in noise level 32 ft. from an operating centrifuge
According to Lyman Waller, operations assistant superintendent at the Albuquerque facility: “Before the panels were installed, verbal communication in the room was very difficult and presented a safety issue. After the panels were installed, the noise level dropped dramatically and communication in the room was significantly improved. We used to have to move to the control room to discuss anything about the centrifuge and walk back and forth to point out issues. Now we can just talk at a slightly elevated level without problems hearing each other.”
Noise-absorbing acoustic panels offer a cost-effective and easy-to-implement solution to taming excessive industrial plant noise generated by pumps, compressors, machine tools and other noise-producing equipment. They are durable, fire-resistant and require little or no maintenance. High-performance acoustic panels are available in aluminum, galvanized or stainless steel and can be customized in size or finish to complement any industrial layout or design.