Environmental noise pollution reduction by improved controlmethods (case study of Mazandaran Thermal Power Plant,Iran)

Noise pollution is an important environmental problem which in comparison to other pollutants, thecontrol of environmental noise has been hampered by insufficient knowledge as well as a lack of criteria.Power Plant industries have worldwide substantial progress and noise pollution is one of considerableenvironmental impacts of various processes of these industries. This cross sectional research aimed tostudy the sound levels in order to control noise pollution at different sections of Mazandaran ThermalPower Plant in Iran. Sound pressure level measurements and frequency analysis were performed using“net” method where the results were compared with ACGIH Threshold Limit Values. It was found thatthe sound levels were higher in most units where the lowest level of sound was at the official unit.Although some methods such as application of absorptive materials, noise barriers and Active NoiseControl system were suggested to reduce the noise pollution. Electricity generator’s fan and Feed WaterPump section produce high levels of noise, therefore a silencer and an enclosure were designedrespectively. The amount of noise reduction for enclosure was ۳۸.۷ dB while the values of insertion lossfor silencer varied between ۱۱ and ۵۲ dB at different frequencies. Also, environmental noisemeasurements around Mazandaran Power Plant as an industrial residential area has revealed that soundlevels were not higher than the admissible standards in Iran.