Like many cities across the world, Brazilian cities struggle with water problems, namely pollution and scarcity. The water bodies of Rio de Janeiro and the Guanabara Bay suffer from extensive environmental contamination due to the discharge of untreated or poorly treated sewage into the natural ecosystem. 70% of the population of the State of Rio, circa 16 million people, are not connected to an urban sewer network (INEA). The rivers, springing clean from the forests above the city, become open sewers as they flow through it. Approximately 20,000 litres of human waste flows in to the bay every second.
The municipality of Rio (and its water company CEDAE) is addressing this, through improvement of large scale sewage infrastructure. However, efforts have bypassed hard-to-reach informal and remote neighbourhoods. As a result, pollution persists, and these neighbourhoods - mostly favelas, housing 6.3 million inhabitants, including the poorest and most vulnerable – suffer from high ground-water pollution, diseases, odour and general environmental decline. It exacerbates socio-economic problems by preventing people from work. The dirty and littered environment also leads to violence and low self-esteem.
It is as though a vital organ is missing from the city. Without universal sanitation, the city is slowly suffocating. Such an absence is the result of a continued reliance on traditional, centralised systems. Implemented in the 1850s in Paris and London, this linear system of hiding waste underground in sewers and transporting it outside the city to large treatment plants – away from our eyes and outside our habitats – has critical vulnerabilities. It brings with it high transport costs in moving water/wastewater from one place to another, as well as necessitating labour intensive, disruptive work to create the sewers that make the system effective.
In Rio, many connections are missing. The largest treatment plant runs at 10% of its capacity as a result. In the hard-to-reach communities, the permanent growth, density, violence, topography and remoteness have added another barrier (excuse) to implementation.
There is also a lack of trust between the inhabitants of Rio and authorities. Billions of R$ have been lost ‘cleaning up’ the bay, with no visible results. Inhabitants have lost faith in such large-scale projects, and it’s difficult for actors from top-down and bottom-up to come together to develop feasible solutions that work for all.
Água Carioca addresses lack of sanitation, water quality, scarcity and environmental improvement using three scalable and adaptive elements – rainwater harvesting, septic tanks and constructed wetlands – alongside a community management model.
Constructed wetlands are an effective, proven system in which natural processes remove pollutants from wastewater in a subsurface-flow build-up with no standing water-bodies. This guarantees little chance of human contact with wastewater, no breeding places for mosquitoes, no need for large-scale infrastructural work (lengthy, costly sewers), no transportation of dirty water and 50% less transportation of clean water.
This essential shift from a centralised to a decentralised model uses a series of small interventions to close the loop locally, cleaning and reusing wastewater directly at source, restoring the cyclical processes of nature. Our approach is collaborative, communicative and holistic. The project demonstrates a way of working, to enhance acceptance and agreement among stakeholders.
Following in-depth field research and anchored in a fractal model, four design proposals (and a city vision) were developed, on scales ranging from one school to a whole city district. The key is concurrent integration of spatial, social, technical and ecological aspects into a systemic and scalable infrastructural design. Together, the designs demonstrate the flexibility of the system and its potential for long-term strategies to transform a whole city.
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