One of the greatest achievements in environmental recovery in Brazil is under way. Lagoa Limpa (Clean Lagoon), a 30-month project initiated by Eike Batista's EBX Group in a partnership with public institutions, aims to have recovered Lagoa Rodrigo de Freitas, one of Rio de Janeiro's best loved landmarks, by September 2010.
Expected to cost R$28 million, Clean Lagoon will not only depollute, but also implement solutions to improve the entire hydric system supplying the lagoon.
Lagoa Rodrigo de Freitas is subject to a natural process called eutrophization, in which an aquatic ecosystem is enriched with several types of nutrients, especially nitrogen and phosphorus. That results in the excessive production of algae, low dissolved oxygen levels, production of toxic gases and other impacts.
Land occupation around the lagoon and human actions have intensified that process. Especially since the 20th century, the pouring of domestic effluents into the lagoon waters and progressive landfilling have been major factors in the degradation of the lagoon's ecosystem.
Fish mortality reached outrageous levels in episodes such as the one in March 2000, when 100 tons of dead fish were removed from the lagoon.
Clean Lagoon Actions
The project started with a test boat and a catamaran for removal of algae and solid waste from the lagoon, in an EBX partnership with Comlurb (Municipal Urban Cleaning Company) and Rio-Águas (Watershed Management Sub-Secretariat).
The excess of algae is associated to the lagoon's ecological imbalance, caused by pollution, and its removal aids the recovery of the ecosystem.
From September 2008 to February 2009, 365 tons of algae were removed from the lagoon.
Beyond waste removal lies preventive work. Over the years, biologist Mario Moscatelli, a Lagoa Rodrigo de Freitas specialist, has pointed out the irregular use of the lagoon as a sewage dump. In a 2000 interview to Folha Online, he blamed Cedae (State Company of Waters and Sewage) for the problem.
Now, in a partnership with Cedae, Clean Lagoon is performing a complete revision of the sanitary drainage system through 10 programas, at a cost of R$5 million.
Sustainable management of solid waste is also in the works. Developed by EBX in accordance with "Reduce – Reuse – Recycle – Hold Liable" principles, the plan involves, for example, the use of algae collected in the lagoon as organic fertilizer for municipal parks.
Oxygenation of the lagoon by means of its only connection with the sea - the Jardim de Alah Canal (between Leblon and Ipanema) - is programmed for the final phase of Clean Lagoon and, according to EBX, will be debated with society.
That phase involves increasing water exchange between the lagoon and the sea.
Studies have been carried out to evaluate the technical and environmental feasibility of installing a duct system under the sand. The duct would connect the Jardim de Alah Canal to the ocean, solving silting-related problems caused by waves on that important outlet.