Date of Award

Summer 1997

Document Type


Degree Name

Doctor of Philosophy (PhD)


Urban Services--Health Services

Committee Director

Rod Handy

Committee Member

Clare Houseman

Committee Member

Martha Myers


This study explores the feasibility of utilizing an amended vermicomposting treatment approach for detoxifying petroleum hydrocarbon contaminated sandy soil. The bench-scale testing of gasoline and diesel contaminated soil using three test soil vessels and one control soil vessel was performed in a laboratory setting for a six week time period. The control soil received no treatment other than distilled water to maintain soil moisture. Treatment 1 consisted of direct application of liquid municipal biologic sludge on a weekly basis. Treatment 2 consisted of the addition of 30 Eisenia foetida earthworms and distilled water. Treatment 3 consisted of direct application of liquid municipal biologic sludge and 30 Eisenia foetida earthworms. The experimental findings showed the greatest reduction in Total Petroleum Hydrocarbon (TPH) concentration occurred in the soil receiving Treatment 3. In addition, the experimental data showed that the individual segments, biologic sludge alone and earthworms alone, provided significant reductions in TPH concentrations. However, the reductions of the individual segments did not exceed the performance of Treatment 3. This finding does, however, indicate that the interaction of the segments can lead to a higher rate of biodegradation within petroleum contaminated soils. The statistical operations performed on the test soils indicated a statistically significant reduction in TPH concentrations occurred in Treatment 3. In addition, the Lower 95% and Upper 95% prediction intervals and the Lower 99% and Upper 99% prediction intervals for Treatment 3 were the largest among the test and control soils. This suggests the amended vermicomposting treatment approach has merit and further studies should be conducted to show the technical feasibility of this treatment option.