Abstract: Arsenic is removed from water and other aqueous feeds by (1) treating the feed with a compound containing cerium in the +4 oxidation state, preferably cerium dioxide, to oxidize arsenic in the +3 oxidation state to arsenic in the +5 oxidation state and (2) removing the arsenic in the +5 oxidation state from the aqueous phase, normally by contacting the treated feed with alumina or other precipitating agent containing cations in the +3 oxidation state.

Abstract: Arsenic is removed from water and other aqueous feeds by (1) treating the feed with a compound containing cerium in the +4 oxidation state, preferably cerium dioxide, to oxidize arsenic in the +3 oxidation state to arsenic in the +5 oxidation state and (2) removing the arsenic in the +5 oxidation state from the aqueous phase, normally by contacting the treated feed with alumina or other precipitating agent containing cations in the +3 oxidation state.

Abstract: A non-linear shaped charge perforator for use in perforating an oil and gas formation into which a wellbore has been drilled comprises a monolithic, axisymmetric metal case in which is disposed a main explosive charge between the front of the case, which is closed with a concave metal liner, and the closed back end of the case. The main explosive charge contains multiple initiation points, preferably two initiation points located about 180° apart on the outside surface of the charge, so that when the perforator is detonated the main charge is initiated such that the metal liner is collapsed into a non-circular jet, preferably a fan-shaped jet, that pierces the casing of the wellbore and forms non-circular perforations, preferably slot-shaped perforations, in the surrounding formation.

Abstract: Arsenic is removed from water and other aqueous feeds by (1) treating the feed with a compound containing cerium in the +4 oxidation state, preferably cerium dioxide, to oxidize arsenic in the +3 oxidation state to arsenic in the +5 oxidation state and (2) removing the arsenic in the +5 oxidation state from the aqueous phase, normally by contacting the treated feed with alumina or other precipitating agent containing cations in the +3 oxidation state.

Abstract: A non-linear shaped charge perforator for use in perforating an oil and gas formation into which a wellbore has been drilled comprises a monolithic, axisymmetric metal case in which is disposed a main explosive charge between the front of the case, which is closed with a concave metal liner, and the closed back end of the case. The main explosive charge contains multiple initiation points, preferably two initiation points located about 180° apart on the outside surface of the charge, so that when the perforator is detonated the main charge is initiated such that the metal liner is collapsed into a non-circular jet, preferably a fan-shaped jet, that pierces the casing of the wellbore and forms non-circular perforations, preferably slot-shaped perforations, in the surrounding formation.