Abstract: Groundwater, or other water contaminated with chlorinated organic contaminants, is passed through a permeable body of iron particles. The particles are coated with nickel, but the coating is incomplete, in that, in patches, the iron is directly exposed. The contaminants break down under prolonged proximity to the iron, the nickel enhancing the catalytic effect. The rate of breakdown is much faster than when bare iron particles were used. When the nickel is alloyed with phosphorus, or boron, even more rapid breakdown rates are achieved.

Abstract: Treatment of halogenated hydrocarbon contaminants in groundwater is accomplished by passing the water through a bed of granular iron (43). An electrical circuit (47) is promoted for providing electrons for reducing the contaminant. The circuit may be made using a DC supply, by configuring an electrolytic circuit, or by providing a layer of a second metal such as zinc placed next to the iron bed, thereby creating a galvenic circuit.

Abstract: Water contaminated with halogenated organics, including chloroform, trichloroethane, solvents, pesticides, etc. is treated by passing the water through a permeable mixture of activated carbon and iron fillings. When the mixture is brought to a negative Eh voltae, the metal causes the contaminants to undergo chemical breakdown. The activated carbon acts to retard the contaminant, giving it a long residence time close to the iron. The negative Eh conditions demand oxygen exclusion, such that a favoured application is to place the mixture in a trench below the water table in an aquifer, in the path of a plume of contaminant. The mixture may also be contained in a tank above, or in, the ground. An inert filler material, such as sand, may be included in the mixture.

Abstract: Contaminated groundwater is treated in-situ, by funnelling the water through a gate or gates (23) in a watertight in-ground wall (18). Treatment material in the gate (23) breaks down the contaminant, or otherwise removes the contaminant from the flowing water. A removable caisson is first driven into the ground, excavated, and then a receptacle, for the treatment material, is lowered into the hollow interior.

Abstract: Groundwater is contained under highly reducing conditions. The Eh value is brought down to -100 or -200 mV, at which the contaminant breaks down, probably by a hydrolysis reaction. The contaminated groundwater is fed through a trench containing a metal such as iron filings, which is effective, under strict exclusion of oxygen, and over a period of time, to lower the Eh. Alternatively, the water may be pumped through an enclosed tank containing iron, or other metal, filings or other high-surface-area form.