Impact of Microwaves and Water On Acoustical Signatures of Yard And Kitchen Refuse Compost

Abstract

Acoustical technologies have been used to evaluate characteristics of ecosystems, including soil, demographics and organism behavior. In our research, the acoustics of four states of yard and kitchen refuse compost were analyzed. These included: compost with and without water, and microwaved compost with and without water. The acoustics generated by the microwaved and non-microwaved composts were recorded in a sound chamber. Water was then added to the control and microwaved samples. Subsequently, the acoustics were recorded again. Sonograms were produced for each of the four treatments and the data analyzed in relation to sound Power Spectral Density (PSD). With the addition of water, the nonmicrowaved compost became acoustically active. The PSD was more than five times greater (p < 0.0001, ANOVA repeated measures) than the microwaved compost with and without water and the non-microwaved compost without water. Most of the PSD for all four treatments was in the lower kHz frequency levels (1-4). KHz frequency level one contained the majority of the sound. Compost plus water, had significantly more PSD at kHz level 1 than the sum of kHz levels 2-11. Most of the remaining PSD was found in the lower kHz frequencies. It is concluded that: 1) compost can be considered as a place where organisms are often dormant, and 2) compost can be activated with water used as a pulsing agent.