Organic compounds need to be removed from water by the municipality before it can be sent out to the distribution network. This is done by activated carbon. The organic compounds may be a nuisance (taste and odour) or may represent a health issue (such as pesticides and pharmaceuticals) After a year or two in service the spent carbon is usually economically and environmentally reactivated so that it can be reused in the plant.
Softening and de-alkalisation
Softening is the process of removing calcium and magnesium from water. The DWAS guideline for drinking water is currently that total hardness should be limited to between 50 - 100 mg/l as CaCO3 , where possible. Hard water also causes scaling of pipes and boilers.
Alkalinity can also contribute to the scaling potential/ aggressiveness of the water. Ion exchange resin is an effective method for removing both alkalinity and hardness
Speciality ion removal
Specific problem contaminants such as, arsenic, antimony may make a water source unfit for human consumption, but they can be removed to produce water that is potable.
Iron, manganese, nickel, and other metals like lead and thallium can be removed from ground water using ion exchange. For ground water remediation applications, or contaminated boreholes often there are also issues with nitrates and fluoride, which can also be treated for effectively with ion exchange and reverse osmosis.
Boron, iodine, bromine/ bromate, perchlorate, chromate may also be removed with the above technologies, but specialised advice is required for the application.