Abstract: A method for treating a fluid by providing a raw fluid to a process tank. The raw fluid may be water having varying degrees of contamination or another type of fluid. The method further consists of adding an ion exchange resin to the process tank to form a raw fluid/ion exchange resin mixture. After the fluid has been sufficiently contacted with the ion exchange resin, treated fluid is removed from the process tank through a membrane filter located within the process tank. The method is completed by regenerating the ion exchange resin within the same process tank.

Abstract: A method of removing metal or metalloids, arsenic in particular, from groundwater or another source of contaminated water. The method comprises providing a water source, contacting the water source with CO2, whereby the pH of the water source is lowered to produce pretreated water, contacting the pretreated water with a metal or metalloid complex-adsorbing substance whereby contaminants are separated from the remainder of the pretreated water to produce metal or metalloid-depleted water, and stripping the CO2 from the metal or metalloid-depleted water, whereby the pH of metal or metalloid-depleted water is increased. A system for metal removal utilizing the CO2 process is also provided.

Abstract: A method of removing metal or metalloids, arsenic in particular, from groundwater or another source of contaminated water. The method comprises providing a water source, contacting the water source with CO2, whereby the pH of the water source is lowered to produce pretreated water, contacting the pretreated water with a metal or metalloid complex-adsorbing substance whereby contaminants are separated from the remainder of the pretreated water to produce metal or metalloid-depleted water, and stripping the CO2 from the metal or metalloid-depleted water, whereby the pH of metal or metalloid-depleted water is increased. A system for metal removal utilizing the CO2 process is also provided.

Abstract: A method for treating a fluid by providing raw fluid to a process tank, adding an ion exchange resin to the process tank to form a raw fluid/ion exchange resin mixture, removing treated fluid from the process tank through a membrane filter located within the process tank, and regenerating the ion exchange resin within the process tank. The method may be set up as a batch process or as a continuous process using a magnetic ion exchange resin and continuous withdrawal of the magnetic ion exchange resin from the process tank by use of a magnetic separator. The method may also consist of reusing the regenerant in multiple regeneration steps and periodically filtering the regenerant to restore its regenerative properties. Alternatively, an upflow bed of ion exchange resin may be used to treat the raw fluid before membrane filtration.