Operação sustentável em sistemas de distribuição de água: uma análise sob a ótica da produção mais limpa (P+L)

Abstract

Water supply systems have a number of factors that influence this process. Social, economic and environmental aspects reveal how sustainable water distribution can be. The challenge of guaranteeing access to water for the entire world population is to find a balance between these three pillars of sustainability. In Brazil, numerous hospitalizations are caused by the lack of access to quality water. The present work seeks in a distribution system, passing through its physical components, technical instructions and operational routines, the evaluation of this, in order to obtain the lowest cost and the least water withdrawal from the sources using cleaner production strategies (P + L). Other objectives are listed and relate to the evaluation through the water footprint and the energy incorporated in the main process, distribution itself and in the production process of inputs such as chemicals and pipes. The conception of a socio-environmental tool that interrelates the volume produced, the volume billed and the consumption/generation of electricity is also one of the objectives of this study. For the execution of this work, the methodology used was based on four scenarios that were simulated in the EPANET hydraulic simulation software. Scenario 1 dealt with the modeling of a conventional supply system for high areas with its typical components (supported reservoirs, water elevations and elevated reservoir). The second scenario changes the previous format with the installation of a turbogenerator and the removal of a water lift and two reservoirs. Scenario 3 shows the increase in billed volume over the previous model and, consequently, the reduction of apparent losses. Scenario 4 addresses all other implementations and adds control of distribution pressure through the inclusion of three pressure regulating valves. The results presented show that as the proposed implementations are inserted through the simulated scenarios, the variables volume produced, volume billed and consumption/generation of electric energy get closer within the socio-environmental tool called the 3Ss diagram of water distribution. In the same way, the water footprint and the incorporated energy follow the trend of improving their numbers through the four scenarios. At the conclusion stage, it is possible to see significant percentage reductions in physical losses through pipe leaks, about 54.6%. The reduction in apparent losses from scenario 3 is in the order of 45.5%. The incorporated energy (kWh/m³) shows a significant reduction from scenario 2, from 8.57 in scenario 2 to 4.95 in scenario 4. The study concludes that the main objective of proposing a sustainable distribution system from the perspective of cleaner production was fully achieved as well as all the specific objectives listed in the format of this research. At the end, it is listed as possible future works the evaluation of the sludge of the treatment plants, a study on the replacement of pipes and the details of their impacts and the carbon emissions from water supply systems and sanitary sewage systems.