In-situ methods for treatment of waste sludges hold great promise for efficient remediation of sludge at waste disposal sites, such as the diverse and complex sludges from the O.E. MacDougall site near Brockville, Ontario. This report presents results of laboratory testing of natural bioremediation techniques using six representative soils and sludges obtained from the MacDougall site. Four of six samples contained concentrations of hydrocarbons typical of petroleum products and solvents. The report includes descriptions of the characterisation of the organic chemistry and microbial populations of the soils, as well as of the experiments conducted under aerobic, methane oxidising, anaerobic-denitrifying, sulphate reducing, and methanogenic conditions.