Avaliação do potencial de reúso de água residuária da ETE Dom Nivaldo Monte para fins não potáveis

Abstract

The wastewater reuse for non-potable purposes is an environmentally sustainable alternative able to preserve potable water in order to supply the demand for its potability. The study carried out at the Sewage Treatment Station (STS) Dom Nivaldo Monte, located in Natal, management by Companhia de Águas e Esgotos do Rio Grande do Norte (CAERN) consists in evaluating the reuse potential of treated effluents for non-potable purposes. The methodology is divided in literature review; evaluation of reuse types and criteria; characterization of the area of study; data search for characterization of treated sewage; characterization of demands and proposition of reuse alternatives based on the compatibility between the required demand and the characteristics of the STS treated effluent. The results indicated satisfactory values for parameters such as pH, electrical conductivity, dissolved oxygen and suspended solids. However, the concentrations of BOD5 and Fecal Coliforms were higher than those required in the Environmental Protection Agency (EPA), NBR 13969/1997, Basic Sanitation Research Program (PROSAB) and Brazilian state and municipal legislations, and an additional biological treatment and improvement in the disinfection process was recommended. The demand for some urban uses was small, however, for residential buildings and aquifers recharging, the flow was higher than the one at the STS. In the industrial sector, the demand is 14% of the STS’s effluent flow and in the agricultural branch, it was verified that it would be possible to irrigate 368 ha of non-food crops. Therefore, the STS has a significant potential for reuse, capable of meeting demands in the urban, agricultural and industrial sectors, provided that adequate adjustments are made.