The method describes how to determine the oxygen content in water using a WTW measuring device.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Oxygen is present in water in varying concentrations. The oxygen content of cold tap water has a significant impact on iron pipes. If the water exhibits an oxygen deficiency (less than 2–3 mg/l O2), iron pitting can occur, since a protective layer between the water and pipe cannot form.
However, for boiler feed water, the absence of oxygen is normally required (depending upon the type of boiler, no more than 0.02–0.5 mg/l should be present) in order to prevent corrosion. The oxygen determination is vitally important (BOD5 value) for testing and evaluating wastewater.
If an electrode system, usually consisting of a gold cathode and a silver anode, is polarized under suitable conditions, any oxygen present in solution is reduced. The change in the polarization voltage that takes place as this occurs is directly proportional to the partial pressure of the oxygen (according to CLARK). The partial pressure and the volume of the gas are also proportional.