Análise da concentração de cloro livre, cloro total, PH e temperatura em alguns pontos de consumo abastecidos pela rede pública de distribuição na cidade de Curitiba/PR

Abstract

The systems of treatment and distribution of water use chlorine and derivatives in treatment plants to disinfect water, however in the distribution network can occurs contact with impurities that could contaminate the water distributed with organisms who can cause health problems for users. Therefore, it’s necessary to mantain a free residual chlorine to ensure potability and the absence of pathogens in all points of consumption, but the free chlorine, on contact with the substances present in the pipes, reacts and decays concentration throughout the system, in addition, in the current legislation isn’t allowed excessive use of chlorine, as this may be harmful to the health of users by constant consumption. So was measured at some points of the water supply network of the city of Curitiba / PR the free and total chlorine amounts present in water, as the pH and temperature, to verify compliance with the legislation in charge. In the measurements, is used a photometer to measure the concentration of free and total chlorine, phmeter for pH and a thermometer for fluid temperature. Occurred with weekly measurements, on 12 points in the city of Curitiba, for 19 weeks, in 4 neighborhoods, served by water treatment plants of Iguaçu and Passaúna, which this analyzed points in the city of Curitiba, the Basic Sanitation Company meets the premises of the Ministry of Health ordinance nº2914/2011, with an average concentration of free residual chlorine of 0.97 ± 0.04 mg/L, within the normative range of 0.2 to 2 mg/L, and pH 6.9 ± 0,2, respecting the range recommended by the Ministry of Health from 6 to 9.5. For data analysis, it has used the theory of errors, including comparisons between points, regions and treatment stations in order to verify the differences related to the treatment, decay and attendance of ordinance MS 2914/2011. With this process noticed that the decay of free chlorine between some points, different flow directions of the estimated preliminarily, pH, free and total chlorine content different between points served by different treatment plants, among the analyzed. However, there were difficulties in the analysis relative to decay, correlations of pH and temparature with free chlorine content in network, for lack of information about the existing supply network and mainly by the lack of data on the amount of chemicals measured in station and raw water quality in the collection period, as the operational informations about the Company that would be vital to decay analysis and correlations between pH and free chlorine content.