(ZA9501283-A)      A process for the decontamination of a medium comprising a particulate material contaminated with one or more metal species comprises the steps of: (a) treating a body of the medium with microbially produced sulphuric acid so as to solubilise the metal species as a metal sulphate; (b) treating the leached metal sulphate by bioprecipitation process which converts the sulphate to an insoluble sulphide; (c) sepg. hydrogen sulphide produced during the bioprecipitation from the insoluble metal sulphide; and (d) oxidising the sepd. hydrogen sulphide to form a reusable source of a sulphur-contg. ingredient.    USE -   The metal contaminants may include mercury, cadmium, barium, chromium, manganese and lead, radionuclides such as actinides and fission prods.. The medium to be decontaminated may comprise soil, rock particles, dredgings, sediment, sludge, process residue, slag from a pyrolytic process or furnace dust.    ADVANTAGE -   The process enables biological systems to remediate metal contaminated land. The process provides a permanent soln. to the contamination problem, allows the simultaneous treatment of metal and organic contaminants, and minimises the use of harsh chemicals which could harm the environment. The size of sec. waste streams is minimised and certain metal contaminants may be reused. The process may be applied in-situ or ex-situ.    (EP788394-A1)      A process for the decontamination of a medium comprising a particulate material contaminated with one or more metal species comprises the steps of: (a) treating a body of the medium with microbially produced sulphuric acid so as to solubilise the metal species as a metal sulphate; (b) treating the leached metal sulphate by bioprecipitation process which converts the sulphate to an insoluble sulphide; (c) sepg. hydrogen sulphide produced during the bioprecipitation from the insoluble metal sulphide; and (d) oxidising the sepd. hydrogen sulphide to form a reusable source of a sulphur-contg. ingredient.    USE -   The metal contaminants may include mercury, cadmium, barium, chromium, manganese and lead, radionuclides such as actinides and fission prods.. The medium to be decontaminated may comprise soil, rock particles, dredgings, sediment, sludge, process residue, slag from a pyrolytic process or furnace dust.    ADVANTAGE -   The process enables biological systems to remediate metal contaminated land. The process provides a permanent soln. to the contamination problem, allows the simultaneous treatment of metal and organic contaminants, and minimises the use of harsh chemicals which could harm the environment. The size of sec. waste streams is minimised and certain metal contaminants may be reused. The process may be applied in-situ or ex-situ.    (JP9509096-W)      A process for the decontamination of a medium comprising a particulate material contaminated with one or more metal species comprises the steps of: (a) treating a body of the medium with microbially produced sulphuric acid so as to solubilise the metal species as a metal sulphate; (b) treating the leached metal sulphate by bioprecipitation process which converts the sulphate to an insoluble sulphide; (c) sepg. hydrogen sulphide produced during the bioprecipitation from the insoluble metal sulphide; and (d) oxidising the sepd. hydrogen sulphide to form a reusable source of a sulphur-contg. ingredient.    USE -   The metal contaminants may include mercury, cadmium, barium, chromium, manganese and lead, radionuclides such as actinides and fission prods.. The medium to be decontaminated may comprise soil, rock particles, dredgings, sediment, sludge, process residue, slag from a pyrolytic process or furnace dust.    ADVANTAGE -   The process enables biological systems to remediate metal contaminated land. The process provides a permanent soln. to the contamination problem, allows the simultaneous treatment of metal and organic contaminants, and minimises the use of harsh chemicals which could harm the environment. The size of sec. waste streams is minimised and certain metal contaminants may be reused. The process may be applied in-situ or ex-situ.    (US5895832-A)      A process for the decontamination of a medium comprising a particulate material contaminated with one or more metal species comprises the steps of: (a) treating a body of the medium with microbially produced sulphuric acid so as to solubilise the metal species as a metal sulphate; (b) treating the leached metal sulphate by bioprecipitation process which converts the sulphate to an insoluble sulphide; (c) sepg. hydrogen sulphide produced during the bioprecipitation from the insoluble metal sulphide; and (d) oxidising the sepd. hydrogen sulphide to form a reusable source of a sulphur-contg. ingredient.    USE -   The metal contaminants may include mercury, cadmium, barium, chromium, manganese and lead, radionuclides such as actinides and fission prods.. The medium to be decontaminated may comprise soil, rock particles, dredgings, sediment, sludge, process residue, slag from a pyrolytic process or furnace dust.    ADVANTAGE -   The process enables biological systems to remediate metal contaminated land. The process provides a permanent soln. to the contamination problem, allows the simultaneous treatment of metal and organic contaminants, and minimises the use of harsh chemicals which could harm the environment. The size of sec. waste streams is minimised and certain metal contaminants may be reused. The process may be applied in-situ or ex-situ.    (EP788394-B1)      A process for the decontamination of a medium comprising a particulate material contaminated with one or more metal species comprises the steps of: (a) treating a body of the medium with microbially produced sulphuric acid so as to solubilise the metal species as a metal sulphate; (b) treating the leached metal sulphate by bioprecipitation process which converts the sulphate to an insoluble sulphide; (c) sepg. hydrogen sulphide produced during the bioprecipitation from the insoluble metal sulphide; and (d) oxidising the sepd. hydrogen sulphide to form a reusable source of a sulphur-contg. ingredient.    USE -   The metal contaminants may include mercury, cadmium, barium, chromium, manganese and lead, radionuclides such as actinides and fission prods.. The medium to be decontaminated may comprise soil, rock particles, dredgings, sediment, sludge, process residue, slag from a pyrolytic process or furnace dust.    ADVANTAGE -   The process enables biological systems to remediate metal contaminated land. The process provides a permanent soln. to the contamination problem, allows the simultaneous treatment of metal and organic contaminants, and minimises the use of harsh chemicals which could harm the environment. The size of sec. waste streams is minimised and certain metal contaminants may be reused. The process may be applied in-situ or ex-situ.    (CN1146163-A)      A process for the decontamination of a medium comprising a particulate material contaminated with one or more metal species comprises the steps of: (a) treating a body of the medium with microbially produced sulphuric acid so as to solubilise the metal species as a metal sulphate; (b) treating the leached metal sulphate by bioprecipitation process which converts the sulphate to an insoluble sulphide; (c) sepg. hydrogen sulphide produced during the bioprecipitation from the insoluble metal sulphide; and (d) oxidising the sepd. hydrogen sulphide to form a reusable source of a sulphur-contg. ingredient.    USE -   The metal contaminants may include mercury, cadmium, barium, chromium, manganese and lead, radionuclides such as actinides and fission prods.. The medium to be decontaminated may comprise soil, rock particles, dredgings, sediment, sludge, process residue, slag from a pyrolytic process or furnace dust.    ADVANTAGE -   The process enables biological systems to remediate metal contaminated land. The process provides a permanent soln. to the contamination problem, allows the simultaneous treatment of metal and organic contaminants, and minimises the use of harsh chemicals which could harm the environment. The size of sec. waste streams is minimised and certain metal contaminants may be reused. The process may be applied in-situ or ex-situ.