Efeito das variáveis meteorológicas na dessalinização solar de água na região litorânea de Alagoas

Abstract

Although 11,6% of the world's potable water is placed in the Brazilian territory, the water is not well distributed because only 3% of it is available for a 52 million population. Besides, the annual climate variability of this region is responsible for the lack of water for human usage. Subterranean water has been explored on the attempt of solving this problem, but unfortunately no drinkable water has been found, due to the elevated amount of salts founded in it. Therefore, this study has the objective of analyze the effects of meteorological variables, season, salinity and water layer, over the process of potable water production and solar desalinization. The study was based on the data obtained from two desalters one filled with pure water and the other with salt water, with salinity changing between 800 mg L-1 and 1600 mg L-1.The experiment started in June of 2007 and finished in march of 2008. Moreover, summer and winter were statistically compared. A suitable parameter, capable of provide a satisfactory simulation of water production potential under specific climate conditions, was developed. During the winter, regardless the salinity, the results shows that the technique is not worth using in the Brazilian Northeast, and only 0,9 L m-2 of water were produced. Although, during the summer, the technique showed great results on both desalters, though the one filled with pure water had a relatively greater efficiency of 23% over the other, recording a daily production of 2,7 L m-2 against 2,2 L m-2, enunciating an inverse relation between salinity and production efficiency. The precipitation, whether not intense, is not unfavorable. The best conditions for solar desalinization are settled when the daily mean temperature of the salt water achieves 40°C, global solar radiation over 18 MJ m-2 day-1 and wind speed over 6 m s-1. The water layer also showed an inverse relation with the production, leading us to believe that insert small water layers into the desalter is more efficient.