Composting has typically been used to treat agricultural wastes, yard wastes and sewage sludges which most often contain negligible concentrations of hazardous organic substances. Other wastes including household refuse, industrial wastes and hazardous wastes often contain greater concentrations of hazardous organic substances which could pose a threat to human health or the environment during treatment or after disposal. Some of the organic hazardous substances found in the waste may be amenable to treatment by composting. A series of research projects have been conducted on the fate of volatile organic chemicals found in municipal and hazardous wastes, and the fate of polynuclear aromatics and explosives during composting. Volatile organic chemicals are rapidly lost during the initial few hours to days of composting both in aerated static pile and in-vessel composting systems. In-vessel composting has been shown to be effective in degrading 65-83% of nitrocellulose propellants in a 6-8 week period. This resulted in first order half lives of 7.7-13.6 days for the nitrocellulose. In-vessel composting of hazardous American Petroleum Institute separator sludge wastes (K051) resulted in the rapid loss of spiked volatile organic chemicals including ethylbenzene, m-xylene, and dimethylnaphthalene. It also resulted in biodegradation which decreased the residual concentrations of anthracene, chrysene and phenanthrene. All of the volatile organic chemicals released in municipal solid waste at the initiation of composting vaporized within a few hours or days at the longest. The results demonstrate that composting can be used to decrease the concentration of hazardous organic substances, but that the more volatile constituents may vaporize, rather than degrade.
