Diesel fuel released into the environment can contaminate ground water, degrade potable water supplies and cause the collapse of fisheries. They are toxic to both animals and humans and can affect the liver, lungs, kidneys, and nervous system leading to cancer as well as immunological and reproductive effects. The objectives of this study were to review current Canadian regulations pertaining to diesel fuel and to evaluate the current remediation methods using five criteria: efficiency, applicability, cost, time and cleanliness. PAHs are deemed toxic under the Canadian Environmental Protection Act but no standards have been set for PAHs in diesel. The Canadian Council of Ministers of the Environment (CCME) has developed Canada-Wide Standards for Petroleum Hydrocarbons in Soil (CWS PHCS) while the Atlantic PIRI has implemented a Risk Based Corrective Action (RBCA) for the Atlantic region. The remediation methods included soil washing, landfilling, incineration, thermal desorption, radio frequency heating, chemical addition, landfarming, biopiling, composting, bioventing, liquid delivery and bioreactors. The bioreactors studied included: static bed, continuous mix, horizontal drum, fungal compost, slurry-phase, DITS, biofilters and packed bed bioreactors. The results showed that the biological methods were more effective than nonbiological ones and the bioreactors scored the highest among the biological methods. Eight criteria were then used for the evaluation of bioreactors: efficiency, time, cost, maintenance, simplicity, release of VOCs to the atmosphere, containment of contaminants and control of operating parameters The results showed that the continuous mix bioreactor was the most effective system

The effectiveness of in-vessel bioremediation in reducing the concentration of toluene in contaminated soil under continuous and intermittent mixing conditions using invessel composting system. The results showed that there was a startup period (60 h) during which the average temperature rose from 21 to 32 and 40°C (and then remained constant) for the bioreactors with continuous and intermittent mixing, respectively. The increase in the temperature demonstrated the conversion of the complex organic carbon into H₂O, CO₂ and energy during mineralization (cell respiration process) of carbon. The lower temperature of the bioreactor with continuous mixing (8-9°C) mixing during the steady state period indicating that more heat was lost with exhaust gas from this bioreactor. Little changes were observed in the moisture contents of the mixture. Most of the moisture losses were through the exhaust gas. The analysis of the exhaust gas samples did not show identifiable toluene peaks but some unidentifiable peaks were present. By day 15, about 96.35 and 89.07 % of the initial toluene were removed by the bioreactors with intermittent and continuous mixing, respectively. These results indicate that in addition to reducing the energy requirement by 50 %, the bioreactor with intermittent mixing also reduces the time required for complete degradation. This method of bioremediation is very effective in removing toluene but the production of toluene derivatives during the biodegradation process should be investigated