Urban Resilience from the Ground Up

A small favela in Rio shows how it’s done by building its own sustainable sanitation and energy systems.

CONSIDERED ONE OF THE largest urban forests in the world, the 15.28 square mile Tijuca Forest located in the heart of Rio de Janeiro, faces the great challenge of being surrounded by more than 40 favelas — low-income, working-class neighborhoods. Most of these favelas do not have access to sewage systems. Without an alternative, people living in the favelas end up dumping untreated household sewage into the environment.

This is a reality that community activist Otavio Barros fought for years to change in the favela where he lives: Vale Encantado (Enchanted Valley), located just 10 miles from the famous Christ the Redeemer statue in Rio de Janeiro.

Nestled within Tijuca Forest in Rio, Vale Encantado is home to only about 100 people. Despite being settled more than 150 years ago, no water supply or sewage collection services ever arrived here. Photo by Douglas Dobby, courtesy of Catalytic Communities | Sustainable Favela Network.

Without a proper sewage system, Enchanted Valley’s sewage was being dumped in makeshift holes around Tijuca. Much of this waste seeped into the ground or flowed until mixing its way into a waterfall in the middle of the forest. The waterfall looks inviting, especially on hot days in Rio, but, until recently, was unsafe to bathe in.

Barros is a member of the Vale Encanto Cooperative, which offers guided tours that showcase the landscapes of this urban forest and end with a traditional meal at a community-run restaurant. (The cooperative is part of the Sustainable Favela Network, which is made up of community organizers from about 180 favelas seeking socio-environmental resilience and partner organizations.)

In 2007, when he brought a group of tourists to the waterfall, one of them wanted to bathe in it. “I alerted a tourist that he couldn’t swim in the waterfall because of the household sewage. That made me even more determined to solve this problem,” Barros recalls. So he started looking for solutions.

VALE ENCANTADO IS PART of a region within Tijuca Forest called Alto da Boa Vista. Human settlement in Tijuca, which is part of the Atlantic Forest Biosphere Reserve (that protects what remains of the Atlantic Forest along 1,900 miles of Brazil’s eastern coast) dates back to the early 1800s. Vale Encantado, however, gets its name from an unfinished luxury condo complex that never got built — authorities halted its huge construction in the 1960s, after only one condominium unit was built.

According to historians, Tijuca Forest has never been the same since the Portuguese royal family’s arrival in Brazil in 1808. The family also invited over other French and Dutch nobles as well as farmers escaping from Napoleon Bonaparte’s troops, leading to widespread clearing of forests for homes and farms. The forest area, with its milder climate in the higher elevations, became a refuge from the summer heat for Rio de Janeiro’s wealthy families. That higher-elevation environment was also suitable for coffee plantations, and several plantations cropped up on forestland as well. Workers and owners of these plantations lived there until 1861, when, in light of deforestation leading to growing water shortage and flash floods in Rio, Emperor Dom Pedro II ordered the area be reforested and prohibited coffee production and farming there.

A panoramic view of the iconic Christ the Redeemer statue at the top of Corcovado Mountain in Rio. Vale Encantado is located just 10 miles from the statute that millions of tourists flock to see every year. Photos by Artyom Sharbatyan/Wikimedia Commons.

The Vale Encantado Cooperative also raised funds and installed a rooftop solar power system last year.

However, land within the forest again began to be used for flower monocultures in the following century, and was later mined for granite as well. But mining activities were banned when the city began implementing more stringent environmental policies ahead of the 1992 Rio Earth Summit. As a result, the local economy, which had long been dependent on some form of natural resource extraction or the other, stagnated and many families moved elsewhere. Only those who had deep ties to the land, or did not have the economic means to leave, stayed back.

Today, Vale Encantado is home to only 40 families that add up to about 100 people. Despite being settled more than 150 years ago, no water supply or sewage collection services ever arrived here.

The favela’s plight isn’t unique. Brazil ranks 101 among 195 countries in a United Nations global ranking for sanitation services coverage. About 45 percent of the country’s population, some 94 million people, do not have access to proper sanitation services. According to the United Nations, poor sanitation makes people more vulnerable to disease transmission. Also, it reduces human well-being and social and economic development.

The Brazilian government plans to improve water and sanitation services throughout the country under a new sanitation framework launched in 2020. Under the initiative, the government aims to ensure that 99 percent of Brazil’s population has access to clean water and 90 percent to sewage collection and treatment by 2033. However, it will be a long while before these services reach small, hard-to-reach communities like Vale Encantado.

It took Barros and his colleagues at the cooperative years to figure out a solution to their sewage problem and then raise enough funds to pay for it. Setting up a network of pipes that would run down the mountain and connect the favela to Rio’s existing sewage network, which was at sea level, was prohibitively expensive, so they had to look for alternatives.

In 2011, Barros sought help at the Pontifical Catholic University of Rio de Janeiro, where he worked as an administrative assistant. There, he met Leonardo Adler and Tito Cals, then environmental engineering students who were researching biodigesters as a technology for favelas and isolated communities. Today, the duo run Taboa Engenharia, a company with the social purpose to contribute to the universalization of sanitation.

Taboa Engenharia helped the Vale Encantado community design its own biodigester and artificial wetland to process its sewage that would cost a quarter of the price of connecting the favela to Rio’s sewage network.

Local residents were employed to help build the biodigester — an igloo-shaped concrete tank in a downhill section of the favela that can receive the sewage collected from the houses above via a pipeline. Photo by Douglas Dobby, courtesy of Catalytic Communities | Sustainable Favela Network.

The Vale Encantado Cooperative’s goal with the biodigester is not only to clean up the local environment and improve living conditions, but also find ways to create employment and income for the favela’s residents through sustainable tourism initiatives. Photo by Douglas Dobby, courtesy of Catalytic Communities | Sustainable Favela Network. Photo by Douglas Dobby, courtesy of Catalytic Communities | Sustainable Favela Network.

“The biodigester is a social technology since the community understands it is the best technology for their reality,” Adler said. “What we do is a participatory diagnosis… and we present the possible solutions from the set of technologies that we work with.”

Work on the project started in 2014 and took eight years to complete, as the project depended on donations and funding and work had to be paused a few times when. The last home in the favela was connected to the biodigester in May 2022. (The community already had a smaller biodigester in a restaurant run by the cooperative that had been donated by a non-governmental organization. In that system, the organic material is food leftovers, which when crushed produces natural gas that goes straight to the restaurant’s stove.)

Local residents were employed to help build the biodigester — an igloo-shaped concrete tank in a downhill section of the favela that can receive the sewage collected from the houses above via a pipeline. Sanitation engineer Adler explains that the water-cleansing treatment system resembles the human stomach. In fact, it is an adaptation of two models: a Chinese-design, fixed-dome biodigester and a floating garden or wetland.

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First, the sewage goes into the biodigester where it is decomposed by anaerobic bacteria that feed on the organic matter present in the sewage water. The product of this reaction releases gas, which can be put to various uses, including for cooking. Some of this gas is already being piped into a few homes in a test phase of the project.

The partially clean water from the biodigester then passes through a second tank, basically a wetland covered with marsh plants, which absorbs nutrients. “In this system, the first stage removes the organic load, and the filter garden takes away the nutrients, such as nitrogen, phosphorus, and potassium, which [would otherwise] cause the pond water to eutrophy and turn green,” Adler explained. The final clean water coming out of this system is then allowed to return to the environment where it flows into nearby streams and replenishes the local water table. Another decomposition outcome is solid waste that needs to be removed every three or four years. After drying, that can be used as fertilizer.

Unlike most favelas in Rio, Vale Encantado is not very dense. It has only 27 houses spread over a territory of approximately eight soccer fields, where plant life around is rebounding. “As the community takes care of the environment, the vegetation is taking over surrounding houses,” Barros said. The sewage treatment system has also helped reduce mosquito populations in Vale Encantado.

Barros and the Vale Encantado Cooperative’s goal with the biodigester is not only to clean up the local environment and improve living conditions, but also find ways to create employment and income for the favela’s residents through sustainable tourism initiatives.

“I am fighting to offer people sources of income so that they avoid looking for other ways, such as drug trafficking or the militia,” Barros said. To that end, the cooperative also raised funds and installed a rooftop solar power system last year. The installation was done with the help of residents who were given training and paid for their work. The system is now linked to Rio’s electrical grid and is helping lower residents’ power bills.

Barros hopes that his small favela’s efforts will serve as inspiration for the other favelas in Tijuca Forest as well as any other low-income community across the world that faces similar challenges.

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