TRACE ORGANIC-COMPOUNDS IN LANDFILL GAS AT 7 UK WASTE-DISPOSAL SITES

The trace volatile organic compounds (VOCs) in landfill gas were exami ned at seven U.K. waste disposal facilities. Over 140 compounds were i dentified, of which more than 90 were common to all seven sites. The g roups of compounds and concentrations observed were alkanes, 302-1543 mg m(-3); aromatic compounds, 94-1906 mg m(-3); cycloalkanes, 80-487 m g m(-3); terpenes, 35-652 mg m(-3); alcohols and ketones, 2-2069 mg m( -3); and halogenated compounds, 327-1239 mg m(-3). The observed variat ions in landfill gas composition were largely attributed to difference s in the waste composition and the stage reached in the decomposition processes at each of the sites. Three sites were found to have total c hlorine concentrations, derived from the organochlorine compounds in t he gas, of above 250 mg m(-3). Chlorine contents of this level were co nsidered to be potentially damaging to landfill gas fueled engines use d for electricity generation. Chloroethene (>0.1-87 mg m(-3)) was iden tified as the most abundant toxic component. Chloroethene levels in th e landfill gases from two of the sites studied were found in excess of the U.K. maximum exposure limit by a factor of 5 and 3. Total VOCs em issions from four of the seven sites studied were estimated to be of t he order of 10(4) kg/yr.