ETE Atuba Sul is one of Sanepar's main sewage treatment plants. In operation since 1997, the plant currently serves approximately 855,000 inhabitants in the eastern region of Greater Curitiba. The treatment process employed at the plant consists of 24 anaerobic reactors (UASB type) complemented by physical-chemical post-treatment with dissolved air flotation and accelerated decantation. The resulting sludge (approximately 5 t/h) is dewatered in centrifuges and then dried in a rotary drum-type thermal dryer using biogas, sludge and complementary plant biomass as an energy source. 
Work is currently underway to expand the WWTP to serve approximately 1,050,000 inhabitants (2,100 L/s average flow), including the conversion of the treatment processes to activated sludge (primary decanters - 12,000 m³ total, 4 aeration tanks (8,000 m3 each) and 4 secondary decanters with 13. 000 m3/each), anaerobic digestion of the sludge (4 digesters with 7,500 m³ each), estimated generation of 12,000 Nm3/d of biogas to be used for thermal drying of the residual digestate, generation of electricity (500 Kwe), recovery of energy from the motor-generators and thermal drying to heat the sludge digesters.