Petroleum sludge bioremediation and its toxicity removal by landfill in gunder semi-arid conditions.

In this investigation, petroleum sludge landfilling was carried out in order to assess the biodegradation degree and the final product quality. The microbial analysis showed a good microorganism proliferation which reinforces the biodegradation process. The total mesophilic and thermophilic microflora evaluated symmetrically as they increased at the intermediate stage and decreased at the final. The C/N and NH4+/NO3-ratios decreased while the polymerization degree increased at the end of the landfilling process. The total polyphenols and total petroleum C6 to C22hydrocarbons were removed by 71.6% and 73% respectively, and that affected the reduction of the phytotoxicity in a positive way. All these changes are in agreement with the efficiency of the biotransformation process and showed that petroleum sludge and filling reduced the toxic organic compounds and led to a stable final product.