An Investigation of the Chemical and Physical Changes Occurring During Commercial Composting

Abstract

In this study, the chemical and physical changes in the composting material, along with the emissions of volatile compounds, have been monitored during a 49 day composting period in a commercial composting operation. In addition, samples of composting material, taken from the commercial operation, have been monitored in automated laboratory scale composters. The measurements conducted on the solid samples included: pH, volatile matter, bulk density, air voids, carbon, hydrogen and nitrogen. In addition, the gaseous volatiles were monitored for odor, as well as gas composition as determined by gas chromatography/mass spectrometry. The results clearly indicated that while the behavior of the composting material was different in the laboratory scale unit, in comparison to what was observed in a commercial composting operation, the laboratory method gave valuable information on the compostability of the material, unobtainable in the larger unit. Based upon an evaluation of the physical and chemical parameters measured, a great deal of information was obtained regarding the progression of the composting process and the identification of possible problem areas where biological activity may have been compromised.