Análise comparativa do índice de perdas na distribuição no sistema de abastecimento público de água: caso de Itaguatins-TO

Abstract

The distribution loss index (IPD) is the difference between the water produced and consumed by the users of a system, and is expressed as a percentage. The volume of water lost is a problem that occurs in all countries and cities in the world, with variations only in the amounts lost. The objective of this research was to calculate and propose actions to reduce the water loss rate that occurred in the public supply system of the city of Itaguatins-TO in the period from 2019 to July 2022, and compare with those that occur in 20 municipalities of small size in the state of Tocantins. In this municipality, it was calculated that the IPD in the year 2019 was 63%. Subsequently, it was identified that the root causes of these losses were: commercial system with outdated registration, lack of active leak control programs, lack of actions to combat fraud inspection, lack of leak repair optimization training, and, due to the presence of old hydrometers, being observed 241 of these meters with year of manufacture ranging from 1996 to 2004, and that presented visible problems of undermeasurement. After having acted with continuous actions on the root causes, in the year 2022 (until July) the IPD of this municipality was 42%. When comparing the loss index in the distribution of Itaguatins-TO, with that of other 20 (twenty) small municipalities, it was observed that in 2019, it occupied the 7th position of the greatest losses and that in 2020 it was occupying the 6th position of the smallest, due to the index of the other municipalities analyzed having increased, in general. In 2019, 52% of the twenty municipalities analyzed had loss rates greater than 60%; already in 2020, this scenario reached 76% of these locations. A systematic review was carried out, with two sets of keywords, namely: "Water losses", "real losses", "apparent losses", "leaks" and "water losses", "water distribution networks", "non- revenue water", "loss reduction", to identify the currently existing loss reduction technologies. It was observed that, normally, loss control actions are usually implemented using a set of alternatives to enhance the results of loss reductions. In Itaguatins-TO, some of the actions suggested in the literature review were used, among which we mention: renovation of the water meter park, inspections to detect and regularize fraud, improvements in procedures and commercial management, with training and updates registers and active control of leaks. The research presents a case study that calculated and provided reductions of 33% in the rate of losses in distribution, after the implementation of actions on its root causes, so that in the year 2022, the IPD of this municipality was 42%. Thus, this study can serve as a reference for companies and professionals that have water supply systems with similar characteristics to the study.