Research on proposing solutions to reduce noise for the operation of air compressors in wastewater treatment system

Currently, aerobic biological methods are widely used for wastewater treatment. During the wastewater treatment process, air is forced by an air compressor into the biological treatment tank with high capacity, so, noise pollution often occurs during the system operation. This is affecting the health environment for workers, staff, and the surrounding population. Therefore, it is necessary to investigate and design a cover to reduce noise for the air compressor but not affect the operating efficiency of the device. The results in this study showed that after 30 minutes of continuous operation, the temperature around the air compressor increased by 2.5oC (from 29.5 to 32.0oC). The noise reduction is 4.0 dBA in case a polyurethane foam layer of 5 cm is used, and the noise reduction is 14.0 dBA if it is replaced with a mineral wool layer of 5 cm. The noise reduction is 17.0 dBA when combining the outer with a 5 cm polyurethane foam layer and the inner with a 5 cm mineral wool layer. Further, the noise reduction is reduced up to 24.0 dBA in case two layers of mineral wool (5 cm thick each) are used to form a homogeneous mass. Thus, using porous materials combined with mineral wool allows to reduce the noise level in accordance with the requirements of the QCVN 26:2010/BTNMT regulation (70 dBA).