Water management is a problem but not a top priority in many of Brazil’s major cities. Typically, there are more pressing problems to be solved, and budgets are notoriously limited. For these and other reasons, the authors are using a low-tech approach that can be implemented quickly and easily for their Água Carioca project.
With a population of around 6.5 million, Rio de Janeiro is the second largest city in Brazil after São Paulo. As in many metropolises in South America, urban development has failed to keep up with population growth. On the city’s mountainsides especially, informal settlements have arisen, and these are growing denser and more populous. In Rocinha alone, which is probably the largest favela in South America, an estimated 200,000 people live shoulder to shoulder under hazardous sanitary conditions. Most of the city’s wastewater – 18,000 liters per second – is flushed into Guanabara Bay as raw sewage.
Engineer Eva Pfannes (pictured, left) studied at the Stuttgart State Academy for Art and Design and at the Bartlett School of Architecture in London. Born in Ingolstadt, Germany, she has worked in the offices of Maxwan in Rotterdam, Zaha Hadid in London, and Studio Makkink & Bey in Rotterdam. In 2003 she founded Ooze Architects with Sylvain Hartenberg in Rotterdam, the Netherlands. Sylvain Hartenberg (pictured, right), born in Paris, studied in Strasbourg at the Institut national des sciences appliquées de Strasbourg and in London at the Bartlett School of Architecture. The architect worked in Paris for Architecture Studio and in London for Terry Farell and Sheppard Robson. Eva Pfannes and Sylvain Hartenberg are not only business partners but a couple in private life.
Governments set priorities, and that’s no different in Rio de Janeiro. But because water quality doesn’t directly affect productivity, as do for example poor roads or power outages, other projects are often given priority. Making matters worse, the favelas of the megacity are at best only semi-institutionalized. Roles and responsibilities are not clearly defined so it ’s always easy for officials to pass the buck. Thus, the first task of the project team was to visit all the key officials and star t convincing them of their plans. In doing so, another hurdle for the realization of the project soon became evident. Although city administrators were interested in implementing a water-treatment project, it was quickly made clear that the city lacked the necessary funds.
Currently, wastewater from Rio’s favelas is dumped into the ocean via a network of pipelines, open channels, and sometimes via makeshift ditches – a foul-smelling, environmentally detrimental, and unhealthy situation. Wastewater management in Rio de Janeiro is failing mainly due to two big problems: First, although there is a water treatment plant outside the city, it’s only operating at partial capacity. Because the sewer network is incomplete, only about ten percent of the wastewater is sent there and treated. And second, the infrastructure installed during the urbanization in the 1960s and 1970s fails to meet today’s requirements, and political and financial difficulties have prevented further improvement.
The approach of Água Carioca is persuasively simple: If the big solution fails, switch to many small solutions. For instance, groups of 10 to 15 houses share a constructed wetland. Each house has its own cistern and septic tank. Rainwater is collected in the cistern, and sewage is collected in the septic tank. It is pre-treated before being fed into the open, constructed wetland along with the rainwater. There, plants and microorganisms provide further purification of the water until it is clean enough to be reused for toilet flushing, washing, and irrigation. The full cycle takes about a week, and 90 percent of the water can be reused at the end. The other 10 percent is lost through evaporation. As sediment accumulates in the septic tanks; it must be cleaned out every two years.
As part of their project, the architects developed design proposals to show that the low-tech principle, which is comparable to that of natural swimming pools, works at both the smallest and the largest scales. At the smallest scale, a modified Água Carioca could provide wastewater treatment for a school – and serve as an example of sustainability there as well. At the midsize scale, based on a system for the favela Morro da Formiga with its approximately 4,500 inhabitants, it was shown that the constructed wetlands can provide public green spaces in addition to wastewater treatment. In the end, the principle of the project could even help relieve the heavily polluted Guanabara Bay, gateway to the city of millions.See more
Rotterdam-based Ooze Architects was selected as one of six groups to be featured in short films in the Creative Industries Funds annual report. The project of Eva Pfannes and Sylvain Hartenberg won LafargeHolcim Awards Bronze 2017 Latin America and was praised for creating an active relationship between water management and the community.
Eva Pfannes explains how funding from the Dutch government allowed their project on efficient water management system for favelas to be developed. The project addresses basic sanitation and effective environmental improvement in Rio de Janeiro and São Paulo – making water treatment visible in the urban realm.See more
As one of the three main LafargeHolcim Awards winners for Latin America in 2017, “Urban Circulatory System” automatically qualified as a finalist in the Global LafargeHolcim Awards 2018. All 15 finalist project teams were asked to submit an updated and more comprehensive entry that was evaluated by a global jury in March 2018.
The results of the global phase of the 5th LafargeHolcim Awards competition were announced on March 28, 2018.
Eva Pfannes and Sylvain Hartenberg from Rotterdam, the Netherlands, developed an efficient water management system for favelas in Rio de Janeiro. Rainwater is collected, and wetlands and septic tanks for filtration are introduced. A key part of the comprehensive concept is public participation in the development process. “By making water treatment local and visible, the proposed scheme creates an active relationship between water management and the community,” stated the jury.Read more » más información (Spanish) »
This project localizes water treatment, cleaning wastewater where it is produced. Rainwater harvesting, septic tanks, and wetlands are introduced in informal settlements to manage the wastewater now flowing through the neighborhood as open sewage. The improvement in public health also reduces CO2 output and stabilizes the ground, helping to prevent landslides. Implementation is envisioned as a fractal approach, from the grouping of several residences, to schools, to whole neighborhoods.Read more » más información (Spanish) »
Closing the loop: turning linear flows into cycles
As all resources on the planet are finite, real sustainability can only be achieved through restoring the cyclical processes of nature. Água Carioca focuses on the resource water: local streams, rainwater and waste water. It closes the loop at the local scale, seeing waste water as a resource and leveraging natural processes to meet local needs. It uses constructed wetlands as an effective and proven treatment to clean waste water. Natural processes remove pollutants in a subsurface flow system with no standing water bodies. This guarantees little chance of human contact with waste water and no breeding places for mosquitoes. There is no need for large scale infrastructural work such as lengthy and costly sewers, no transportation of dirty water and 50% less transportation of clean water.
Making processes visible, beautiful and enjoyable
People generally find it hard to relate to the term sustainability as it is something very abstract. Sewage in particular is perceived as dirty and unworthy of design, although it is precisely this stigma that prevents innovation in this field and has led to the current situation. Água Carioca challenges the common idea that sewage needs to be hidden underground. Instead it makes processes of the urban metabolism visible, understandable and part of a system. In this way each project becomes an educational tool. It combines technical solutions with persuasive communication strategies that enhance acceptance and agreement among residents and other involved parties. Citizens engage during the process and become aware of the water cycle and water recycling.
A fractal structure, an incremental method of implementation
Change of large scale structures and engrained habits requires a development strategy that combines thinking on multiple scales, time horizons and that enables actors to implement and test small steps towards a credible long term vision. Água Carioca uses a fractal structure to approach the implementation of sustainable sanitation: from our body to a house, a community to the whole of Guanabara Bay. Due to their fractal nature, constructed wetlands are applicable in a variety of scales and spatial situations. They have the ability to grow and adapt to various contexts. Água Carioca uses this quality to lead a transition to a more sensible use and management of natural resources. The fractal structure is the model for implementation as well as for building trust to take next steps.See more
A sanitation project for a Rio de Janeiro favela turns linear flows into cycles, makes processes visible and is scalable …
Sanitation system in informal communities: This project localizes water treatment, cleaning wastewater where it is …
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