The consortium Serra Ambiental, formed by the companies Sonel Engenharia Ltda. (leader), Construtora Aterpa M. Martins Ltda. and Mauá Participações Estruturadas S/A, has submitted the best proposal for the concession for the expansion, operation and maintenance of the sewage system of the city of Serra in the state of Espiritu Santo (Brazil).

Serra Ambiental offered a discount of 22.05 % in the proposed fee beating the other three proposals:

• Consortium formed by Saneamento Ambiental Águas do Brasil Ltda. (leader), Carioca Christiani-Nielsen Engenharia S/A and Sanevix Engenharia Industrial Ltda. (16,17%);
• OAS Investimentos S/A (2,94%);
• AEGEA Saneamento e Participações S/A (2,20%).

The concession period is 30 years and the estimated investment required is R$ 409 million (US$187.4 million) during the first eight years. Total revenue of the contract are estimated at R$ 806 million (US$356 million).

Bidding documents were subject to public consultation between April and May 2012. Estruturadora Brasileira de Projetos (EBP) carried out the structuring of the concession project.