Reuse of effluents from cattle slaughterhouses: multicriteria evaluation

Abstract

Cattle slaughterhouses generate a large amount of effluent with a high concentration of organic and inorganic compounds. However, the choice of appropriate technologies can produce effluents with sufficient quality for the practice of reuse as a strategy for saving water. This study aimed to determine the efficiency of effluent treatment systems from cattle slaughterhouses to promote the reuse of effluents, specifically for fertigation. The multicriteria analysis was employed, adopting the ELECTRE I method. The effluent treatment alternatives, the definition of the degree of importance, and the weights of each established criterion were considered. The estimated volume of effluents generated in slaughterhouses in Brazil was 85.374 million m³/year, with a high concentration of biochemical/chemical oxygen demand, nutrients, oils, and greases, solids, and E. coli. The treatment technologies that showed the best performance were UASB reactor + ultrafiltration and activated sludge + ultrafiltration, producing effluents with compatible quality for agricultural reuse under Brazilian legislation.