Tratamento da água da chuva por radiação ultravioleta usando energia fotovoltaica

Abstract

Scarcity, deterioration in the quality of water sources and increased demand for water have been a problem for both developing and developed countries. Given this scenario, the use of alternative sources such as rainwater harvesting and utilization is a feasible solution. In remote places, without water and electricity supply, the use of a rainwater harvesting system with ultraviolet disinfection and powered by an isolated photovoltaic panel can be the solution for water and energy supply. However, the focus of this research is to use this system for non-potable water disinfection, ie toilets and external taps. Thus, in this work the efficiency of the isolated photovoltaic system and the quality of the rainwater after passing through the ultraviolet (UV) germicidal lamp is evaluated. In order to measure water quality, 13 analyzes were carried out at the Water Treatment and Treatment Laboratory of the Federal Technological University of Paraná (UTFPR). Water analysis of the cistern and after the passage through the UV disinfection system were performed using different flow rates to determine which would be more feasible for the system. The measured parameters were pH, temperature, color, turbidity, total dissolved solids and total and thermotolerant coliforms. These parameters have standards of use in accordance with NBR 15.527 of 2007 regarding the use of rainwater for non-potable purposes. In addition to these analyzes, a sample was analyzed in a laboratory of the Sanitation Company of Paraná (SANEPAR) referring to cistern and the maximum flow for the parameters of total and thermotolerant coliforms. Rainfall and solar irradiation data are collected to determine if the system powered by photovoltaic energy is viable in the city of Curitiba. The research showed that the city of Curitiba does not have a dry season, so the rains occur throughout the year, and thus, the system remains in operation throughout the year. The results for water analysis demonstrated that the UV disinfection system is efficient, and at the mean and minimum flows had 100% improvements in water quality for coliforms. These same flows were within the standards established by NBR 15527 of 2007. The isolated photovoltaic system proved to be effective for UV disinfection, since the irradiation rates were feasible even in the winter period, when solar irradiation is generally lower. The maximum and average flow rates have the volume of water suitable for use in a residence of up to four people. However, the values of the minimum flow would not supply the daily quota for the toilets. Finally, it was concluded that the selfsufficient system, that is, connected to photovoltaic energy, operated in a positive way during all the seasons of the year demonstrating that the junction of these three slopes can be very beneficial.