چكيده لاتين :
Conventional and experimental methods were studied for the remediation of petroleum contaminated sediments from a dam previously used to collect acid run-off from a sulfur mine. The man-made lake had been neutralized, but benton ite rich sediments remained contaminated with very weath ered hydrocarbons (sediments with ~ 50,000-60,000 mg/kg Total Petroleum Hydrocarbons were used in this study). Biostimulation, bioaugmentation (with native microorganisms) and chemico-biological stabilization, all resulted in similar reductions (14-16%) in the TPH concentration over a three month period. The land farming treatments resulted in variable reductions in toxicity, ranging from nil to complete, while the chemico-biological stabilization treatment, not only eliminated acute toxicity but also result ed in a slight stimulation (~103-109%) of the test organism in the bioassay (Microtox) . All three
treatments reduced polyarom atic hydrocarbons of probable carcinogenicity to below or nearly below the Mexican norms, reduced Toxic Chara cteristic Leaching Proceedure leachates to<1 mg/L, and left the material in a pH range of 7.0 -7.8. The chemico-biological stabilization has the advantage of only requiring initial mixing of the chemical and organic reagents instead of daily aeration, thereby reducing operating costs . This method is also able to treat very
difficult sites at low cost, relying on biological humification processes which are accelerated in a humid tropical and semitropical environment. The total unit cost of the chemico-biol ogical stabilization treatment was estimated to be ~60% of that for land farming in the southern Gulf of Mexico region.
