Preliminary acoustic test on densified swine solid fraction

The aim of this study was to evaluate the acoustic characteristics of the solid fraction resulting from the solid-liquid separation of pig slurry in order to use this material during realization of facilities. In this study two different types of material have been investigated: swine solid fraction and swine solid fraction mixed with sawdust. These substrates were composted for a period of three months in order to stabilize them. The tests were conducted using different levels of pressure on the two materials for 60 seconds each. In order to verify the acoustic absorption coefficient, cylinders with different densities were made by using a hydraulic press (Pampuro et al., 2011). The method under normal sound incidence was used and the tests were performed with the Impedance tube device (also known as Kundt's tube device). Two different diameters for each cylinder (29 mm and 100 mm) were required to run the tests in order to cover the frequency range from 100 Hz to 5000 Hz. The tests carried out showed that the analyzed materials have good acoustic performances. More detailed analysis is undergoing to confirm the positive initial test results obtained with the sound at normal incidence method.