Abstract: A system for in-situ bioremediation of contaminated soil and ground water wherein porous inorganic support spheres such as diatomaceous earth pellets are treated by inoculation with selected non-pathogenic microbes, ie. bacteria, for destroying or converting the contaminate. The contaminates may be hydrocarbons, sulphides, cyanides, nitrates, heavy metals and other chemicals. The porous cells of the diatomaceous earth pellets provide a home not only for the microbes but also for oxygen, water and other nutrients to help sustain the life of the augmented colonies of microbes introduced in the pellets. The contaminated soil is prepared for treatment by creating fractures and fissures therein using fluid pressure introduced through spaced apart holes drilled to selected depths. The depth of the drilled holes and the hole spacing will depend on the area of contamination.