Patent ID: 7321073

Claim:
A method for treating low solids content sediment from a body of water, said sediment including halogenated organic compound and heavy metal contaminants, the method comprising the steps of: (1) dewatering the sediment to obtain a stream having a concentrated solids content of about 50% by weight comprised of inorganic and organic fractions; (2) adding air or oxygen, a supplemental fuel, and a reactant to the concentrated solids stream, said reactant selected from the group consisting of sodium carbonate, sodium hydroxide, hydrogen peroxide, iron, aliphatic hydrocarbons, and mixtures thereof; (3) pressurizing the concentrated solids stream to a pressure in the range of about 800 to 2500 psi; (4) preheating the pressurized stream by passing the stream from step (6) through a heat exchanger; (5) conveying the preheated stream into a reactor with the fuel addition sufficient to maintain a self-sustaining reaction temperature to dehalogenate and decompose or denature the contaminant compounds; (6) returning the dehalogenated and decomposed or denatured stream to the heat exchanger to provide heat for the preheating step; and, (7) reducing the pressure of the stream for further processing by directing the stream through a small variable orifice to generate a liquid and atomized solids fraction and a volatilized fraction; (8) condensing the volatilized fraction; (9) combining the condensate with the liquid and atomized solids fraction to provide a second concentrated solids stream; (10) adding the water fraction from the dewatering step to the second concentrated solids stream to provide a dilute solids stream; and, (11) gravimetrically separating the solids from the dilute solids stream in stages to separate the heavy metals from the remaining dilute solids stream to provide a heavy metals solid stream and a remaining solids stream.