Brazil's Rio de Janeiro city works department has launched a 2.9bn-real (US$1.8bn) tender for a sanitation concession in the city's western district.
The call for bids was published on Thursday (Aug 25) in the city's official gazette, according to a municipal government release.
Proposals must be submitted on October 18.
The plan, being carried out in cooperation with state water and sewerage utility Nova Cedae and the city government, involves collecting and treating wastewater in 21 neighborhoods. Rio's municipal waterworks organization Rio-Águas Foundation will oversee the work.
The initiative aims to quadruple the area's existing sanitation network through the construction of 19 wastewater treatment plants and 221 pumping stations, benefiting some 1.7mn residents.
Wastewater collection and treatment in the region should reach 40% by 2016 and 90% by 2036.