TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Process: The contaminate is pre-treated by biodegradation before and after chemical oxidation.The contaminate with a microbiological consortium at suitable condition for microbium consortium to mediate solubilization or biodegradation of organic compound.Preferred Material: The contaminate is a particulate material, surface soil, subsurface soil, sand silt, clay, sediment, loam, slurry, colloid, liquor, industrial waste fluid, ground water, pool, pond or lake.The particulate material is gravel, pebbles, stone, stone chips, rock, ore, mining waste, coal, coke, slag, concrete, brick, construction material, demolition material, vermiculite, synthetic resin or plastic.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The contaminating organic compound is a polycyclic aromatic compound selected from naphthalene, fluorene, phenanthrene, anthracene, pyrene, chrysene and benzo(a)pyrene.The chelator compound is iron-chelator compound which is catechol or gallic acid or salicylic acid.Preferred Composition: The buffering salt maintains the pH of 5-8, preferably 6-6.5.The organic compound is insoluble in aqueous solution.The chemical oxidation yields product(s), at least one product being biodegradable to the microbial consortium.The oxidizing agent is hydrogen peroxide and produces an oxygen radical.The buffering salt is salt with a pKa (5-8), preferably calcium carbonate.The molecular weight of the organic compound is reduced and the organic compound is substantially mineralized to carbon dioxide and water.The organic compound is toxic and carcinogenic in animals and humans.The reaction products and biodegradation product(s) are non-toxic and non-carcinogenic in animals and humans.The organic compound is from industrial manufacturing, industrial processing, chemical processing coal tar processing, oil refining, energy generation or a natural process.The organic compound is chlorinated and selected from trichloroethene, perchloroethene and polychlorinated-biphenyl compound.The microbial consortium comprises Alcaligenes, Sphingomonas, Pseudomonas, Rhodotorula, Burkholderia, Ochrobactrum, Rhodococcus, Xanthomonas and/or Actinomyces. SPECIFIC COMPOUNDS - The transition metal is iron and is present as perchlorate.    EXAMPLE - Polyaromatic hydrocarbons (PAH) including naphthalene, fluorene, phenanthrene, anthracene, pyrene, chrysene, and benzo(a)pyrene, were dissolved. Stock solution obtained and Quakertown silt loam were placed in a flask for artificial contamination and the solvent was mixed with the soil and allowed to evaporate in fume hood. PAH concentration was 600 mug/g of soil. Microbial consortium was cultured from coal tar-contaminated soil. PAH were dissolved in methanol and PAH-methanol solution was used as substrate for enrichment. The consortium capable of degrading several PAH was obtained and used for biodegradation. Fenton's reagent was generated by mixing hydrogen peroxide and aqueous ferrous sulfate solution (FeSO4.7H2O). Ferrous sulfate was added to polyaromatic hydrocarbon-spiked soil. Hydrogen peroxide was added to soil slurry and reaction was performed at room temperature. Before adding ferric irons and hydrogen peroxide, chelator such as catechol or gallic acid was added to soil slurry and calcium carbonate was applied to maintain pH at 6-6.5 throughout the reaction. Biodegradation was performed. Dichloromethane and acetone were added to the soil and soil-solvent suspension was shaken for extracting PAH. Anhydrous sodium sulfate were mixed with PAH-containing solvent to remove residual water completely from solvent. 100% fresh PAH spiked to Quakertown silt loam were recovered.