The construction of the Sao Romão’s Wastewater Treatment Plant (ETAR) was held to a nominal capacity of 1,196 m3/d, sized to serve a population of 9,496 inhabitants. Its realization related to a preliminary treatment (wet sieving, desanding, degreasing), secondary treatment (biological treatment with sludge activated in extended aeration system in oxidation ditch, secondary sedimentation), tertiary treatment (nutrients removal, microtamização, disinfection by UV) and sludge treatment (thickening, mechanical dewatering).