Noise control design of ventilation system in operating layer of an underground sewage treatment plant

The noise control design of ductless ventilation system in an underground sewage plant is presented. The noise control design can make the ground acoustic environment good and has little impact on the plant boundary in the field measurement after completion. It is found that the sound power level predicted by the methods in literatures is higher than that given by the fan manufacturers. It is proposed to adopt the measured sound power level provided by the fan manufacturer in the project.The application of array structure muffler and plate structure muffler in the project is compared. The array structure muffler is adopted in the project, because its insert loss is larger under the same length condition. The acoustic performance of the non-metallic rain-proof acoustic louvre is presented.