The project involves building a cogeneration electric energy plant from biogas, produced through the processing of sludge from the city's Dr Hélio Seixo de Brito sewage treatment plant. Construction is due to last 24 months.

Bidders must have experience building a cogeneration energy system of a similar type with a minimum electrical power output of 500 kW and building anaerobic digesters with a minimum capacity of 6,000 cubic meters.

Companies and consortiums should submit offers on August 28, the notice says.

Although both domestic and foreign companies are eligible, consortiums must be led by a Brazilian firm. Companies must prove at least $4.4 million in capital and consortiums, $5.75 million.

The initiative is being supported by financing from Brazil's national development bank BNDES, the notice said.

Saneago supplies 225 of Goiás state's 246 municipalities with potable water supply and sewage collection and treatment services. Some 4.7 million people are supplied with potable water and 2.1 million are provided with wastewater services.

Currently, Saneago provides potable water in all of the municipalities in its coverage area, reaching 93.6 percent of the population.