Abstract: A device for removing a contaminant from a fluid stream flowing within a conduit is disclosed. The device includes a container and a barrier. The container has a first wall generated about an axis and a second wall generated about the same axis. The first wall defines a first volume therewithin, while the first and second walls define an annular second volume therebetween. Both the first and second volumes are sealed at one end of the device, while at the other end of the device the second volume only is sealed. A filter material occupies the second volume. The first and second walls are permeable to the fluid stream and are capable of retaining the filter material in the second volume. The barrier is impermeable to the fluid stream and creates a seal between the second wall and the conduit wall.

Abstract: A process and apparatus for removing arsenic from aqueous media is described. The process in general utilizes ferrous ion provided by an electrochemical cell which is added to the aqueous media in a first step, followed by mild oxidizing conditions generated by the addition of hydrogen peroxide. The ferrous ion then forms an hydroxide which is oxidized to an oxyferric oxide and the arsenic present at a +3 oxidation state is oxidized to a +5 state whereupon the oxyacid complexes with the oxyferric oxide. A precipitate then is formed which consists of ferric arsenate, and the hydroxy ferric oxide-oxyacid complex. Heavy metals may also be removed by the process.

Abstract: A process for removing heavy metal contaminants from groundwater without injecting anion contaminants thereinto and without providing surface sludge for disposal is described. The process consists of withdrawing a flow of groundwater containing the contaminants and passing the flow of groundwater through an electrochemical cell having at least an anion of iron or an iron containing alloy wherein the cell consists of an anode, a cathode, and a plurality of closely spaced additional electrodes disposed therebetween. The cell then generates ferrous ion and hydroxyl ions into the solution which is then reinjected upstream of the flow. In-situ then hexavalent chromium will be reduced to nontoxic trivalent chromium and will form an insoluble iron containing compound or complex with the hydroxide to immobilize the chromium in-situ. Other heavy metal contaminants similarly will be immobilized by reacting with the iron, or through the absorbent properties of a ferrous iron hydroxide generated.