The base design of the Companheiras Wastewater Treatment Plant, developed within a project that included the construction work, has focused on the liquid phase treatment process. This process comprised the following: an inlet with thick gridding, thin gridding, a grit basin, a cleanser, a compressor for the grains, sand classification and grease concentration; reception equipment, gridding, storage and pumping of the septic tank sludge for the primary treatment; initial pumping station; activated sludge tank with low load aeration; secondary decanter; tertiary treatment composed by microstraining and UV channel disinfection; measurement and discharge in the receiving environment.

To reuse the treated wastewater for services in the wastewater treatment plant, the plant also includes a storage reservoir for treated wastewater, metal filters and a closed reactor ultraviolet disinfection.

Regarding the solid phase, the treatment scheme includes the following organs: the storage of sludge to thicken; floaters; storage of sludge to be dehydrated; centrifuge for mechanical dewatering of sludge and silo storage for dewatered sludge.

The Companheira wastewater treatment plant has been designed to serve 200000 people.