With the objective to reduce the water consumption and the discharge of effluents in a metal industry, a technical and economical evaluation of five treatment technologies was proposed in order to reuse the effluents. Four sites for water reuse were chosen and for each of them criteria were suggested. It was evidenced that in the adsorption with activated carbon and reverse osmosis the effluent treated by these processes could be reused and, with the flowrate projected of 2.5m³/h, the cost attained US$ 1.14/m³ and US$ 1.70/m³ respectively. For the ozone and chlorine dioxide, even so the effluent was disinfected, gave only satisfactory results and the cost attained US$ 0.54/m³ and US$ 0.71/m³ respectively. For the treatment with coagulation/flocculation, all the analyzed parameters were successful in two reuse places, with exception of the TDS. The cost for this technology attained US$ 1.57/m³
Water reuse; activated carbon; ozone; chlorine dioxide; reverse osmosis; coagulation; mechanical industry
