Monitoramento e avaliação socioambiental de sistema compacto para tratamento e uso agrícola de água cinza

Abstract

The water reuse has been shown necessary for industrial, commercial and domestic activities, it has being reality in many countries, but not very widespread in Brazil. The implementation of this practice for agricultural purposes has been seen as an efficient instrument for the management of water resources and the minimization of water scarcity in the Brazilian semiarid region. This study aims to monitor and perform a socioenvironmental analysis of a compact treatment station and agricultural use of gray water, installed in rural settlement of the semi-arid region, composed of septic tank, anaerobic filter and artificial ultraviolet reactor, whose installation took place in experimental area of the Universidade Federal Rural do SemiÁrido, Mossoró/RN. In the period from October to December 2017, the performance of the system treatment was evaluated by physicochemical analysis (Biochemical Oxygen Demand, Chemical Oxygen Demand, pH, electrical conductivity, turbidity, N, P, Na+, K+, Al, As, Ba e Cr) and microbiological (Total Coliforms and Escherichia coli) of gray water with and without treatment, in order to meet the established standards for reuse of water for agricultural and forestry purposes. The socioenvironmental evaluation of this technology consisted of the application of 20 questionnaires, with questions related to the of water reuse in agriculture, to the residents of the Projeto de Assentamento Monte Alegre I, located at Upanema/RN, where three systems of treatment and agricultural use of gray water, with characteristics similar to those of the present study are running. The results indicated that the system showed efficiency in the removal of the studied variables, consequently attending in the maximum permissible standards in the legislation, except for turbidity, potassium, carbonate and Escherichia coli. The socioenvironmental perception about the forms and purposes of water reuse, as well as the consumption of food irrigated with this kind of water, occurred in a positive way, denoting economic and sustainability aspects, as advantages. Although, in a few cases, it had been shown divergence for consumption of this kind of food because of contamination risks as well as the effluent characteristics