Potencial de reúso de efluentes tratados para irrigação na agricultura periurbana no Semiárido Paraibano.

Abstract

Water is a finite and scarce resource, which justifies the search for management and innovation of practices that preserve it. The objective of this research is to quantify the potential for reuse of effluents treated by CAGEPA wastewater treatment plants for irrigation in periurban agriculture in the semiarid region of Paraibano. Data were collected from the 17 Sewage Treatment Plants (ETE), located in the semiarid Paraibano, and operated by the Water and Sewage Company of the State of Paraíba (CAGEPA), during the period from January to December 2019. The following physicochemical and bacteriological parameters were analyzed: Hydrogen Potential (pH), Electrical Conductivity (EC), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Solids (TSS), Dissolved Oxygen (DO), Ammoniacal Nitrogen, Total Phosphorus, and Thermotolerant Coliforms. The data were submitted to descriptive analysis and expressed as minimum, maximum and average values. The potential for reuse was evaluated based on the quality of treated effluents for agricultural irrigation according to the recommendations established by the Basic Sanitation Research Program - PROSAB. The indicators varied in each ETE depending on the month of collection, where it was possible to identify effluents with quality for unrestricted irrigation, although most presented quality for restricted irrigation, with the need for complementary treatment in some months for certain crops, for example, for tomato and vegetable crops. As for the volume of treated effluents generated in the ETEs, there is potential for reuse in periurban irrigation in the semiarid region of Paraibano, especially considering permanent crops where the treated effluents can benefit an area of 2.387,83 ha for an irrigation demand of 12.000 m³ ha-1 year-1, which demonstrates to be a sustainable resource that needs to be regulated in Brazil.