Recycling Pig Slurry Solid Fraction Compost as a Sound Absorber

Niccolò Pampuro,Christian Preti,Eugenio Cavallo

doi:10.3390/su10010277

Niccolò Pampuro, Christian Preti + Show 1 more

Open Access

https://doi.org/10.3390/su10010277

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Abstract

The aim of this investigation was to determine the physical and acoustical properties of compacts made from composted pig slurry solid fraction (SF) in order to assess the potential to recycle this agricultural waste as a sound absorber. The compacts were obtained by compression. The physical parameters investigated were bulk density, durability, and particle size distribution. The acoustical features of the compacts were studied with an impedance tube device in order to verify the acoustic absorption coefficient. Two composts were prepared: pig SF compost without a bulking agent (SSFC) and pig SF compost with wood chips as a bulking agent (WCC). The study’s results indicated that compost particles dimension played a key role in the physical and acoustical properties of the compacts: the smaller the particles, the higher the physical and acoustical properties of the compacts. The densification process increased the bulk density of the investigated composts up to 690 kg m−3 for SSFC and 660 kg m−3 for WWC, with, respectively, medium (77.9%) and low (66.5%) durability. The addition of woody bulking agent significantly reduced the absorption coefficient: the best results, in terms of potential use as a sound absorber, were observed for compacts made from composted pig slurry solid fraction without the addition of wood chips.

Highlights

Noise emission can be controlled by sound absorber materials able to reduce the sound reflected from surfaces [1,2,3]
Adapa et al [40] established a durability scale for compacts: high when the computed value is above 80%, medium when the value is between 70% and 80%, and low when the value is below 70%
The current study investigated the physical and acoustical properties of compacts made from agricultural waste, the pig slurry solid fraction, composted itself (SSFC) and mixed with wood chips (WCC)

Summary

Introduction

Noise emission can be controlled by sound absorber materials able to reduce the sound reflected from surfaces [1,2,3]. The growing awareness towards the environmental implications and health issues associated with these materials has increased the attention being paid to natural materials [5]. In this contest, there is emphasis on the use of green, ecofriendly materials in fields like automotive and building construction. There is emphasis on the use of green, ecofriendly materials in fields like automotive and building construction This trend is growing in the area of acoustic and noise control [6]. A high number of potential candidate materials are available from the biomass in the form of organic fibres, either vegetable or animal in origin, to replace the non-natural materials adopted to manufacture conventional sound absorbers. According to Oldham et al [2], they are inherently sustainable as they constitute part of the carbon and nitrogen natural cycles

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