Contaminants in Water, an Article on Bromine (bromide), Chloride, and Sulfate.
BROMINE:(BROMIDE) Bromine is found in sea water and exists as the bromide ion at a level of about 65 mg/L. Bromine has been used in swimming pools and cooling towers for disinfection, however use in drinking water is not recommended. Ethylene bromide is used as an anti-knock additive in gasoline, andmethyl bromide is a soil fumigant. Bromine is extremely reactive and corrosive, and will produce irritation and burning to exposed tissues. Over 0.05 mg/L in fresh water may indicate the presence of industrial wastes, possibly from the use of pesticides of biocides containing bromine. Bromide is extensively used in the pharmaceutical industry, and occurs normally in blood in the range of 1.5 to 50 mg/L.
Treatment-Reverse Osmosis will remove 93-96% of the bromide from drinking water. Since bromine is a disinfectant, it along with the disinfection by-product can also be removed with Activated Carbon, Ultra Filtration, or Electro Dialysis.
CHLORIDE: (C1-1) is one of the major anions found in water and are generally combined with calcium, magnesium, or sodium. Since almost all chloride salts are highly soluble in water, the chloride content ranges from 10to 100 mg/L. Sea water contains over 30,000 mg/L as NaCl. Chloride is associated with the corrosion of piping because of the compounds formed with it; for example, magnesium chloride can generate hydrochloric acid when heated. Corrosion rates and the iron dissolved into the water from piping increases as the sodium chloride content of the water is increased. The chloride ion is instrumental in breaking down passivating films which protect ferrous metals and alloys from corrosion, and is one of the main causes for the pitting corrosion of stainless steel.The SMCL (suggested maximum contaminant level) for chloride is 250 mg/Lwhich is due strictly to the objectionable salty taste produced in drinking water.
Treatment-Reverse Osmosis will remove 90-95% of the chlorides because of it's salt rejection capabilities. Electro Dialysis and distillation are two more process which can be used to reduce the chloride content of water. Strong base anion exchanger which is the later portion of a two-column deionizer does an excellent job at removing chlorides for industrial applications.
SULFATE: (SO4) occurs in almost all natural water. Most sulfate compounds originate from the oxidation of sulfite ores, the presence of shale, and the existence of industrial wastes. Sulfate is one of the major dissolved constituents in rain. High concentrations of sulfate in drinking water causes a laxative effect when combined with calcium and magnesium, the two most common components of hardness. Bacteria that attack and reduce sulfates, causes hydrogen sulfide gas H2S to form. Sulfate has a suggested level of 250 mg/L in the Secondary Drinking Water Standards published by the US EPA.
Treatment-Reverse Osmosis will reduce the sulfate content by 97-98%. Sulfates can also be reduced with a strong base anion exchanger, which is normally the last half of a two-column deionizer.