Industrial plant noise mitigation starting from the plant first runs

The article summarizes a noise impact mitigation study that was carried out in the Liguria region in Northern Italy, between July 2020 and March 2022 on a large industrial plant that produces zinc oxide. The authors were summoned at the plant first run tests, so this study started without a participation in the industry planning and design phases. We followed the main machine installations and perfected the mitigation project accordingly: priorities were updated after each assessment and new modelization. This approach was carried out with different SPL measurement campaigns and the use of sound-intensimetry and a beam-forming SEVENBEL antenna. A SoundPLAN 3d model was updated step by step, defining a designing ad hoc noise control strategies and solutions, in order to respect the Italian administrative noise regulations. The mitigation works were directed by one of the authors and included different approaches: such as some large cylindrical silencers on the smoke stacks, sound barriers and insulating coatings, as well as fan velocity optimization.