Methanotropics are grown in a bioreactor containing a solid support. They decompose halogenated aliphatic hydrocarbons found in ground water. The growth of the bacteria and the methane concentrations in the biomass reactor are controlled to significantly enhance the degradation of the hydrocarbons.

Selection of mutant methanotrophic bacteria capable of efficiently degrading halogenated hydrocarbons typically found in numerous wastewater sources is described. The mutants are distinguishable from parental strains in having a unique resistance to the presence of copper while exhibiting unusually high degradation rates toward trichlorethylene. Methylosinus trichosporium A.T.C.C. 55314 strains are particularly good sources of the described mutants which may be obtained using a new method of selection and screening. The disclosed microorganisms may be immobilized on various matrices and are particularly adaptable for use in bioreactors. Further, the methanotrophic bacteria have antibiotic resistance to streptomycin or rifampicin B.

The present invention relates to a method of removing contaminating hydrocarbons from regions which are subjected to extreme temperatures. The temperatures are generally outside the range of optimum growth of hydrocarbon-degrading microorganisms. The method can involve the steps of contacting the region with hydrocarbon-degrading microorganisms, and adjusting the temperature of the region contacted with the microorganisms to optimize their growth.

A process for purifying water, wherein the water, which is polluted by a mixture of halogenated compounds, preferably halogenated hydrocarbons, is passed through at least two reactors (treatment stages) packed with a porous material populated by one or more microorganisms, one of the reactors being operated under anaerobic conditions and being followed by an aerobically operated reactor; in this way, almost complete elimination of the halogenated compounds, preferably halogenated hydrocarbons, is achieved.

A process for remediation of contaminated solid materials comprising polynuclear aromatic hydrocarbon contaminated solid materials, polychlorinated hydrocarbon contaminated materials, and mixtures thereof by sequential biological/chemical/biological treatment in which the contaminated solid materials are biodigested under suitable conditions by a first aerobic or anaerobic digestion, producing a first biodigestion product. The first biodigestion product is then contacted for chemical treatment with hydrogen peroxide in the presence of ferrous ion in amounts and under conditions suitable for chemical oxidation, forming a mixture and oxidizing the first biodigestion product, producing biodegradable hydrocarbon product materials having enhanced biodegradability. The product materials are then biodigested under suitable conditions by a second aerobic or anaerobic digestion.