Avaliação da qualidade das águas superficiais e seu reúso na irrigação de áreas verdes do campus sede da Universidade Federal de Campina Grande-PB.

Abstract

The city of Campina Grande-PB has been suffering from a prolonged drought common to the Northeast, which has necessitated developing alternative strategies to mitigate the water crisis. The use of wastewater in agriculture is a practice that has been gaining ground in recent years, however studies that prove its quality must be carried out, as well as the application of treatment techniques that contribute to the preservation of the environment and quality of life of the population. The Federal University of Campina Grande (UFCG) at its principal campus uses water from two small lakes contaminated with wastewater to irrigate the green areas of the campus. In view of the lack of treatment of these waters, this study aimed to evaluate the quality of this surface water used on the campus. The research was carried out between March and October 2016, and water quality was determined by means of a multiparameter submersible probe, plus additional physical-chemical and microbiological analyzes. The results obtained were compared to the values established by Resolution No. 357 of 2005 of the National Environment Council (CONAMA), for surface water quality and were used to calculate the Trophic State Index (EIT) and Water Quality Index (IQA). The IQA of Lake 1 ranged from poor to very poor and the IQA for Lake 2 was classified as poor in all months of study. In relation to the trophic level of Lake 1, the EIT varied between mesotrophic and Eutrophic during the first six months, passing to super eutrophic in the last two months of the study. Lake 2 presented a better EIT in the month of March, but for the other months, it varied between super eutrophic and Hypereutrophic. The water of lagoon 2 presented inferior quality in relation to lagoon 1, and this was due to the channel connecting the two lakes receiving additional effluents from adjacent points of the campus. Another additional factor that maybe relevant to these results on water quality was the contamination of the water with excrement from a large bird population and the entrance of effluents from the CA block and a cafe located at the margin of lake 2. From the results of this study it was concluded that the use of these waters without treatment represent a threat to soil quality, may damage existing vegetation and are a risk to public health, principally to the employees operating the irrigation systems, as well as to people who use the soccer field, and the green areas for rest or leisure. Therefore, it is necessary to implement an effluent treatment system that reduces the polluting load of these waters.