Measurement of Free Residual Chlorine in Drinking Water Using Clean Technologies “Oxidation and Reduction Potential” as an Alternative Technique to the Use of Chemical Reagents

Abstract

In the field of health, one of the main aspects is to ensure access to drinking water, within its control, monitoring and analysis there are some important physical chemical parameters, however one of the most relevant at the time of monitoring of water quality to be able to guarantee the disinfection of this is the analysis of free residual chlorine in an on-site manner in the water treatment plants, however this monitoring is not carried out routinely due to the high costs that it implies and the large amount of chemicals that are used and that end up being released from the environment. This article presents a proposal for the use of ORP sensors or Redox sensors, an electrochemical device that, when in contact with a solution, generates an electrical signal whose voltage varies depending on the capacity of the solution to act as an oxidizing or reducing agent. Which would currently be an alternative to the use of chemical reagents in the measurement of residual free chlorine in drinking water plants, and for this work chlorine acts as an oxidizing agent, therefore the sensor will measure its oxidation capacity in units of millivolts and will relate them to the research obtained from the assessment of the analytical technique by the method of the European Standard UNE-EN ISO 7393-1:2000, “Water quality. Determination of free chlorine and total chlorine. Method by titration with N,N-diethyl-p-phenylenediamine”, and the results obtained will be correlated with the influence of pH and temperature, in order to find an equivalence in parts per million as a unit of residual free chlorine concentration of According to the standard, to validate the method, the precision, accuracy, sensitivity, selectivity, among others, were calculated and it was determined that the sensor readings are related to the concentration of free chlorine present in the water, as well as pH and temperature, the latter being indirectly proportional factors that influence measurements, so it is crucial to control these parameters; There is no linearity in the checks, however, it will be prolonged that the system is accurate for the measurement of free chlorine since it is within the accepted criteria in the validation of analytical techniques, being an adequate and economical alternative for continuous monitoring in Water treatment plants.