METHOD AND APPARATUS FOR MEASURING A RESIDUAL CHLORIDE CONCENTRATION USING A SENSOR, AND WATER TREATMENT SYSTEM USING THE METHOD AND APPARATUS

摘要

The present invention relates to a method and an apparatus for measuring a residual chloride concentration in purified tap water from a variation of slope according to the elapse of time in a value of an oxidation-reduction potential (ORP) sensor for purified tap water. The present invention further relates to a water treatment system using the method and apparatus. The method for measuring the residual chloride concentration in raw water, treated with chloride in a water purifying process, comprises the steps of: the purified tap water flowing into a batch chemical reactor (510); injecting a reactant having a predetermined concentration, which chemically reacts with the residual chlorine, into the batch chemical reactor (510) at a predetermined time interval while measuring the value of the variation of the ORP of the batch chemical reactor (510); and performing a second differentiation on the measured value of the variation of the ORP of the batch chemical reactor (510) using, as a variable, the amount of the reactant injected into the batch chemical reactor (510) so as to calculate an inflection point, and then determining the amount of the reactant at the calculated inflection point to be a break-through point.