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Boues d'épuration Brésil
© Bénédicte Desrus / AFD
Water and sanitation companies in several Brazilian states are carrying out an ambitious project to improve wastewater treatment and recover sewage sludge. This is part of an overall effort to better protect the environment, and advance towards the fulfillment of the Sustainable Development Objectives.

The urban wastewater treatment process creates two sorts of benefits, one more evident than the other. On one hand, it produces purified water (approximately 95%). On the other, it also creates a large amount of by-products, or in other words, sludge. Dehydrated sludge can be used on arable land as compost or for energy production, which also requires a process by which its fermentation and pathogenic potential are reduced. 

In Brazil, state water and sanitation companies serve up to 75% of the population that have access to water. But the territory is still poorly covered: only 54% of the Brazilian population had access to a sanitation service in 2020, and only 49% of wastewater is evacuated before discharge into the natural environment.

Further reading: Improving waste treatment for a better environment in Suriname

Despite a growing need for wastewater and sewage sludge treatment, their recovery is almost non-existent today in Brazil. That’s why AFD agency in Brasilia has launched a cooperation program with its local partners, financed by Fexte resources (Technical expertise and experience exchange fund), in order to improve the management of sewage sludge.

"This sludge is not just waste, it is a source of nutrients and resources, and can be used, among other noble uses, as soil enrichment or in the production of energy,” says Diego Brunelli Ghisi, operational manager of sanitation for CAJ Water Company of Joinville, one of the companies involved. “AFD's support enables us to define the technical, environmental and social solution best suited to our reality.”

The Brazilian water and sanitation companies that are partners of the AFD Group (CAJ, Cagepa - Water and Sanitation Company of the State of Paraíba, and Copasa - Water and Sanitation Company of the State of Minais Gerais) expressed their interest in participating in this cooperation program to identify the best sludge recovery solutions. 

They also intend to develop partnerships at the regional level, create solutions for the reuse/recycling of waste, develop practices already defined, reduce significant operating costs and their environmental impact and employ new technologies in their production process.

AFD is contributing to the fulfillment of the following objectives:

  • Supporting the modernization of Brazilian public water and sanitation companies. For example, lagoons previously used to treat wastewater are being converted into habitats for aquatic plants that purify organic matter and other pollutants. They thus participate in the sludge mineralization process by transforming it into a material with properties similar to those of soil.
  • Promoting cooperation between Brazilian public companies and French companies in the sector

In these ways and more, sludge will be put to much better use.