In the late 1990s, world leaders came together to create the Millennium Development Goals – time-bound, quantified targets for addressing extreme poverty and human health and well-being. Notable among them was to “halve, by 2015, the proportion of the population without sustainable access to water and sanitation.”

The sanitation aspect of this goal centered on providing toilets and ending open defecation. So we built toilets, lots and lots of toilets. Worldwide, 2.1 billion people have gained access to improved sanitation since 1990.

Unfortunately, toilets alone are not a sanitation solution. When feces is not disposed of properly, when a storm causes pit latrines to overflow or a sewer system to fail, disease can still break out. Each day, nearly 1,000 children die due to preventable water- and sanitation-related diarrheal diseases. A major contributor to this persistent public health challenge is that more than 80 percent of wastewater resulting from human activities is discharged into rivers or seas without any pollution removal.

The UN is now focusing on the second half of the sanitation equation. Once poop is captured, it must be safely removed from the urban environment and sustainably stored. The Sustainable Development Goal on water and sanitation, one of the 17 new goals set by the UN in 2015 building on the MDGs, includes a sub-target on “halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.”

A worthy goal, but how do we achieve it in low-resource settings? Rapid urbanization is outpacing infrastructure and municipal capabilities, and concentrating large numbers of people in informal settlements.

One innovative solution that has proven successful in several pilot projects is container-based sanitation, a system similar to how we manage trash and recycling in the United States. Human waste is captured in sealable containers that can be transported to treatment facilities. During treatment, valuable resources such as energy and nutrients are recovered before the waste is disposed of in an ecologically friendly manner.  The waste is isolated, safely transported, and treated. What’s more, income from user fees and sales of recovered resources, such as biogas, briquettes, and compost, contribute to offsetting the costs of collection, transport, and treatment.

In the basic model, users pay a monthly subscription fee. In return, they receive an in-home toilet specifically designed to capture and isolate liquid and solid waste and a bi-weekly collection service. The enterprise providing the service is responsible for the full sanitation service chain, from providing the toilets to collection of waste and safe disposal.

A handful of groups have tested container-based sanitation in low-income countries, including entrepreneurs in Kenya, Ghana, Haiti, and Peru. The first effort to implement the model and complete academic research on impact and cost effectiveness occurred in Haiti in 2011. The initiative was led by SOIL, a social entrepreneurship venture that produces compost from human waste. SOIL partnered with the Stanford start-up Re.Source, led by two recent doctoral graduates Kory Russel and Sebastien Tilmans.

According to a Stanford Woods Institute for the Environment brief on the experience in Haiti, the model was a significant improvement over pit latrines. Low-income households were willing to pay for reliable, high quality, in-home sanitation services. The portability of the toilets reduced investment risk, and the small monthly fee was easier to pay than a large lump-sum to build pit latrines. Regular servicing, via the bi-weekly collection of containers, was also a major improvement over pit latrines, which are often only maintained once every few years.

The portability and modularity of the container-based model may enable governments to finance improved sanitation in informal settlements without the political liabilities of piped infrastructure. The combination of income from user fees, sales of recovered resources, and government investment could provide a sustainable financial model, a feat that has been impossible to achieve via other sanitation schemes.

Implementation has been slow internationally, however. The expectation is that service efficiency improvements, increased productivity, and economies of scale are likely to decrease costs substantially, but the initial pilot phase has relatively high costs as a new business is built up from scratch. Most crucially, container-based solutions are not officially recognized as an “improved sanitation” option by the United Nations, primarily because the public health benefits have not been proven at scale. This decision has serious consequences. Governments and other organizations may be hesitant to invest if container-based sanitation will not bring them closer towards achieving the Sustainable Development Goals.

Kenya, however, has decided the model is promising enough. In May, the government launched a new sanitation and hygiene policy that recognizes container-based sanitation as “improved,” making it the first government or international agency to do so. The endorsement will hopefully stimulate the expansion of the two social entrepreneurship ventures implementing the model, Sanergy and Sanivation, and motivate more sanitation service providers, including local governments, to experiment with the model in Kenya and beyond.

The UN high-level forum on sustainable development held this week and last in New York City provides an opportunity for leading stakeholders to reassess priorities and consider innovation solutions. The Habitat III Conference in Quito, Ecuador, this fall will be another. Kenya’s endorsement of container-based sanitation could be the linchpin to catalyzing broader growth and adoption of this promising solution to a deadly public health challenge.