In Suva, Fiji, a woman washes her dishes in an old bathtub. The wastewater goes straight into the local stream. Children walk barefoot on paths where toilet pipes leak. Pigs live in enclosures among mangroves, and their waste goes directly into the water, which floods homes during storms and high tides. Although many homes have piped water, there are no proper ways to dispose of wastewater.
Similar villages in Makassar, South Sulawesi, Indonesia, lack essential services such as trash collection and city water supply. Some people buy bottled water, while others share shallow wells that often run dry during the dry season. Living spaces and walkways are contaminated by sewage and other forms of wastewater.
Around the world, informal settlements such as these are home to about a billion people. These people have nowhere else to go, so they have created their own communities on land no one else wants. Often referred to as slums, shantytowns, or squatter settlements, these are areas where housing and infrastructure are developed outside of urban planning and are usually considered illegal.
They might all look very different from each other, said Dr Emma Ramsey, an environmental scientist at Nanyang Technological University, Singapore, but they typically all lack essential services, such as wastewater treatment and rubbish collection; they have inadequate sanitation facilities, limited access to clean water, and a lack of formal land tenure.
The United Nations anticipates an additional 2 billion informal settlement dwellers over the next 30 years, mainly driven by rapid urbanisation and unaffordable housing.
Residents of informal settlements are especially vulnerable to extreme weather events like floods, which cause wastewater to spread through homes and lead to serious health issues, such as gastrointestinal illnesses, which hit young kids the hardest.
In children under five, repeated acute episodes of diarrhoea can lead to chronic inflammation in the gastrointestinal tract, which causes poor absorption of nutrients from an already poverty-stricken diet, stunting, difficulties with schooling and concentration, and other factors.
As the climate worsens and floods become more frequent, these communities already living on the margin of society grapple with more extreme conditions.
Nature-based solutions to treat wastewater
In the city, the wastewater solution has been using big pipes to collect and treat sewage. But that isn’t an option for unplanned, unregulated settlements.
A team of researchers from Australia, New Zealand, the US and Singapore has developed a water-sensitive approach to upgrade informal settlements through the Revitalising Informal Settlements and their Environments (RISE) project. This approach integrates ecologically and economically sustainable water infrastructure into landscapes and buildings.
The RISE team believes that using built infrastructure such as toilets, smart boxes, and communal septic tanks, along with natural infrastructure like soil, retarding basins, and wetlands, can replace the use of big pipes, decreasing faecal exposure, improving health and wellbeing, and making these communities more livable.
Involving local people is crucial.Noor Ilhamsyah, Indonesia Build
Nature-based solutions can be very simple. For example, wastewater from a household can flow through biofilters made of plants, sand, and gravel media that clean the water through biochemical processes and into constructed wetlands.
The researchers have selected twelve informal settlements in Suva and Makassar to participate in a randomised control trial. In the trial’s first phase, six settlements in each city are undergoing a water and sanitation upgrade. The researchers will monitor the impacts of these upgrades on the environment and the health of the communities. They will compare the results against the other twelve settlements serving as control. In the second phase of the trial, the control group of settlements will also be upgraded.
In Indonesia, researchers are trialling the use of pre-fabricated modular wetland units. The units, made of glass-fibre reinforced concrete planter boxes, are manufactured domestically in Yogyakarta, Central Java. They are solid and durable and can be installed quickly and removed or relocated as community needs change.
Last October, the team installed the impermeable base layer for a 25-metre wetland in one of the communities in Fiji. They used a geo-synthetic clay liner made with bentonite clay, a more effective and longer-lasting alternative to plastic-based water-proofing products or full concrete found in certain informal settlements.
Indonesia Build team member Noor Ilhamsyah, an urban designer and community architect at RISE, travelled to Fiji to be part of the installation process ahead of similar installations in Makassar. “Discovering RISE in varied conditions broadened my understanding of local contexts.”
Co-designing rather than prescribing
Previous efforts have primarily focused on households, shifting a lot of responsibility for cleaning up water and sanitation to the poorest people in the world, who have the least resources. Also, outreach programs often go into a community, deliver an intervention, and then leave, resulting in a disempowering experience for the people left behind.
Informal settlements differ not only in terms of environmental context but also in terms of community context.Dr Emma Ramsey
In a recent review, researchers tried to analyse and quantify the different forms of nature-based solutions practised in informal settlements in Southeast Asia and the Pacific. They reviewed over 1,700 peer-reviewed studies, reports, and policy documents. The researchers found that community participation plays a crucial role in long-term success.
“Informal settlements differ not only in terms of environmental context but also in terms of community context of who lives there and what they want,” said Ramsey. “RISE is a great case study because we are co-designing these solutions with the community to suit a particular community’s needs rather than just rolling out something that we expect to work for everybody.”
RISE researchers conducted citizen science initiatives, encouraging community members to share their insights on local flood occurrences. In environments where data is often limited, tapping into the firsthand experiences of long-standing community residents becomes a significant and reliable data source.
“Involving local people is crucial,” said Ilhamsyah. It allows researchers to co-design solutions that meet the population’s needs. It also empowers communities to take over once the project is completed and to engage with local governments to seek the support they need.
Monitoring the progress
The project’s goal is to reduce residents’ faecal contamination exposure, and the researchers are monitoring the success of the interventions through sampling and data collection, including blood and stool samples from residents, water samples, soil samples, mosquito trapping, rat trapping, acoustic surveys, and questionnaires.
While researchers expect to share the results from the ongoing trials within the next two years, data from the Indonesia demonstration site in Makassar completed last June show some exciting findings.
The team has observed a marked decrease in almost all contaminants, including E. Coli and other bugs and chemical pollutants.
Compared to a conventional wastewater treatment system in Indonesia, the cost-per-household of constructing the pilot site was lower and offered additional benefits, such as drainage, flood mitigation, water supply, climate resilience and socio-economic benefits – like better year-round access to employment, education and food vendors.
Residents interviewed by the researchers find that the road, which was built to provide flood-safe access to the community while housing key elements of the RISE treatment system, had several benefits, including facilitating the transport of construction materials, enabling social gatherings, and freeing up time for women by making it easier to get to the market and allowing vendors to come into the community for the first time.
“Even when it only rained once, we couldn’t go out to the road directly because it would be inundated with water, there would be grasses, rubbish scattered everywhere. Wood from other people, remaining from their building work, all scattered everywhere,” said one woman living in the settlement.
“[Now] when we wake up in the morning, even though it may be raining, there is no rubbish outside. The road is wide open, and the breeze is blowing.”