Edited by: Maria Elisa Magri, Federal University of Santa Catarina, Brazil
Reviewed by: Christoph Luthi, Swiss Federal Institute of Aquatic Science and Technology, Switzerland; Caroline Saul, Karlstad University, Sweden
This article was submitted to Water and Wastewater Management, a section of the journal Frontiers in Environmental Science
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Container-Based Sanitation (CBS) has rapidly progressed from its inception less than a decade ago to its recent classification as a type of improved sanitation facility by the Joint Monitoring Programme. CBS in many ways represents a sustainable service, as it addresses the entire sanitation service chain; offers a variety of service-based business models; and is affordable to people living in marginalized and informal urban settlements. At the same time, CBS services which have been operating for a number of years have grown relatively slowly. Taking CBS to scale will require solving several diverse challenges, particularly the need for government mandates; regulation; and innovative financing. This paper presents the collective views of some of the world's leading CBS practitioners in an effort to summarize the potential, research gaps, and major challenges to scaling CBS.
Sustainable Development Goal (SDG) target 6.2 aims to provide “access to adequate and equie sanitation and hygiene for all and an end to open defecation.” The objective's indicator is based on the proportion of the population using safely managed sanitation, rather than obtaining access to a basic toilet. Thus, government agencies and municipalities need to upgrade ~4.5 billion people globally to safely managed sanitation services by 2030 (JMP)
SDG target 6.2 is more demanding than the Millennium Development Goal targets. Nevertheless, it provides an impetus to pursue more effective approaches that can serve the entire sanitation value chain. One such example has been the rapid development of container-based sanitation (CBS). CBS consists of an end-to-end service in which toilets collect excreta in sealable, removable containers (also called cartridges). The containers are regularly collected and transported to treatment facilities when full. Since 2010, modern CBS iterations have rapidly evolved into a viable, low-cost sanitation option, particularly in low-income urban settlements where demand for sanitation services is high and on-site sanitation and sewerage are not feasible or cost-effective (O'Keefe et al.,
CBS services have been provided by social enterprises or NGOs, and several city utilities (such as Cape Town and Manila) are adopting CBS as part of their approach to citywide inclusive sanitation (CWIS). Revenues come from customer service fees and the sale of waste treatment by-products, including compost; protein (for animal feed); and energy (Preneta et al.,
In 2018, the JMP formally recognized CBS as a type of improved sanitation facility
However, as noted in a 2019 World Bank report, despite having been operational for a number of years, most CBS services are still operating in relatively early stage development
CBS has several attributes that enable it to complement the existing suite of sanitation solutions to provide a robust citywide sanitation portfolio.
CBS has typically been used where it is infeasible or inappropriate to install sewerage systems, such as in densely populated urban neighborhoods, informal settlements, displaced person camps, or areas with high water tables or risk of frequent flooding (O'Keefe et al.,
Traditional sewerage systems require significant up-front capital investment and reliable water and energy supplies to function (Haller et al.,
In contrast, CBS toilets have a lower capital burden, require less water and energy to operate, and require limited infrastructure or installation, allowing users continuous service even after a move (
CBS sanitation value chain.
Due to the relatively nascent nature of CBS, operators have typically had to act as designers, developers and builders, all while trying to meet health and safety standards for the entire sanitation value chain. However, the individual modules of the CBS value chain could be plugged into existing CWIS systems to strengthen overall sanitation service delivery. For example, Sanivation treatment plants accept both CBS and pit latrine waste, Sanergy integrates organic solid waste into its treatment process, and Clean Team disposes of waste at government treatment facilities.
The use of water to convey waste creates interdependency between the SDG sanitation target (6.2) the SDG water target (6.1). However, it is impractical in many regions to expect water availability and infrastructure to be able to support the implementation of sanitation in addition to providing basic water access. Instead of water, CBS uses dry cover material (sawdust, charcoal powder or unused by-products of agricultural production) or polymer film (e.g., Loowatt) for “flushing
Sanitation is a significant contributor of greenhouse gas emissions (GHG), producing ~2–6% of global anthropogenic methane (Saunois et al.,
A recent study in Haiti found the CBS system there produced less net GHG emissions compared to both waste stabilization ponds and illegal dumping (Ryals et al.,
CBS services encompass the full sanitation value chain, and therefore meets the requirement for safely managed sanitation according to the WHO. Assuming feces are properly handled throughout the service chain, including treatment and safe disposal/reuse, CBS is likely to be an effective solution for limiting the spread of fecal contamination within household and community environments (Preneta et al.,
Two recent reports from the Bill and Melinda Gates Foundation on gender and sanitation noted that in-home CBS services provide women and girls with a private, safe space to use the toilet and manage menstruation and pregnancy
There has been widespread optimism around the potential for CBS providers to be financially self-sustaining given their business-focused approach
Gaining government buy-in at national and local/district levels is essential to extending CBS into unserved areas. However, challenges remain in persuading governments and the wider sanitation sector that CBS is a viable alternative to sewerage.
While CBS has gained official recognition in the 2016 Kenya Environmental Sanitation and Hygiene Strategic Framework as a safe and cost-effective alternative to sewers and on-site sanitation systems, most countries have yet to take any official stance (van Welie et al.,
In an effort to improve the enabling environment, the Container-Based Sanitation Alliance (CBSA) was formed in 2016 and became a legal entity in 2019
There is a significant investment hurdle to ensure a CBS service can start and grow. The unit economics of sanitation and, in particular, the fees that customers can pay (assuming ~2-3% of household budgets) means the economics are difficult. Additionally, there are few examples of full value chain sanitation services in low-income markets and thus few examples of how to pay for such services. More research is therefore needed to compare the costs and benefits of CBS to traditional options and to understand the magnitude of cost savings gained through increasing service densities and economies of scale.
A new CBS service requires capital expenditures on treatment systems, conveyance equipment (i.e. trucks and carts), and toilets. These expenditures can be very expensive and difficult for any single organization to cover on their own. Additionally, by committing to addressing the full sanitation value chain, CBS providers may have higher operational cost as compared to pit emptying services. However, CBS providers are demonstrating that the use of novel treatment technologies which are safe, efficient, and can facilitate resource recovery ultimately make CBS more cost effective. Thus, leveraging public, philanthropic, and private funds to get CBS services running at scale can lead to greater return on investment in terms of public goods (public health and environmental quality) as well as private goods (privacy, cleanliness, and social status) than traditional options in dense urban settlements.
At an operational level, access to capital and longer-term financing mechanisms to scale up CBS services is often lacking (O'Keefe et al.,
Some CBS service providers have faced challenges to hire, train and manage their workforces. In some contexts, local recruitment, and retention of high capacity staff can be challenging, as team members must be interested in working in a low-margin and historically stigmatized sector. Similarly, there can be a lack of fecal sludge experts as education typically focuses on traditional sewerage and wastewater treatment plant operations. Thus, incentivizing the creation of university programs that include training in a variety of sanitation technologies, in similar ways to the Gates Foundation-funded MSc at IHE Delft would be very helpful. Furthermore, governments could provide incentives to encourage qualified professionals to continuing working in nascent sanitation services that currently do not provide the economic security of more established sanitation jobs.
A toilet must be attractive and aspirational to customers, easy to use, durable, and simple to install. It also needs to be attractive to governments and utilities, and meet the needs of their constituents (i.e., politically and culturally acceptable). The toilet user interface can largely be classified by defecation position and anal cleansing preferences (
CBS toilet user interfaces.
Currently, not all CBS services collect urine, as it represents a high added cost due to its weight and volume. While infiltration or urine and graywater may be an acceptable short-term solution, large scale infiltration of urine could lead to elevated nitrate and nitrite levels, as well as pharmaceutical contamination in groundwater (Templeton et al.,
Additionally, more research is need into the impacts CBS services have on access equality and inclusion. Given the potential to positively impact the lives of women and girls, their needs should be at the forefront of future research and design work.
CBS providers have been developing digital systems to support and strengthen service delivery as well as improve the customer experience through better logistics management (Saul and Gebauer,
Transportation needs to be developed in context, especially where there may be poor road infrastructure, high housing density or difficult topography. Several CBS providers use a two-stage model: door-to-door collection of containers with push carts or small motorized vehicles; use of transfer stations for temporary storage; and employing larger trucks for secondary delivery of containers to waste treatment facilities. Transport distance between households and treatment facilities is a key cost driver, and exploring innovative methods for route optimization is an ongoing and needed area of research.
Finally, maintaining hygienic safety throughout the sanitation value chain is essential. Future work that monitors potential contamination failure points and the magnitude of the associated risk in comparison to traditional sanitation options is important for improving the safety of CBS.
CBS has the potential to reach un- and under-served urban communities with sustainable, high quality, cost-effective services that can yield multiple economic, health and environmental returns. However, wider sector buy-in and financing is required—this will help shift the prevailing paradigm to a broader understanding of the suite of sanitation options necessary for achieving inclusive citywide sanitation. There is a need to encourage sanitation and public health ministries and policy makers to include CBS among their sanitation policy options and to structure financing (e.g., targeted investment and tariffs, payment by results mechanisms, etc.) and public-private partnerships to support the expansion of CBS services.
With cities expanding at unprecedented rates and the number of people living in informal urban settlements expected to double by 2030, it is critical that new sanitation technologies and services like CBS be studied and made available to governments and unserved communities
KR, KH, MR, DA, AF, SK, and RB contributed the concept and identification of the perspectives presented. KR wrote the first draft of the manuscript. All authors contributed to manuscript revision and have both read and approved of the submitted version.
KR serves as the Chair of the CBS Alliance. KH, MR, DA, AF, SK, and RB are all members on the steering committee of the CBS Alliance and individually represent organizations providing CBS services in different locations around the world. The CBSA is an alliance of CBS providers (
The authors would like to express our endless gratitude to Tracey Keatman, Molly Case, and Sebastien Tilmans for all their assistance in editing this paper and coordinating the CBSA. Thank you to Kris Russel for creating the figures.
1JMP. (2017). “Progress on Drinking Water, Sanitation and Hygiene: 2017 Update and SDG Baselines.”
2JMP. (2018). “Core questions on drinking water, sanitation and hygiene for household surveys: 2018 update.”
3WB. (2019). “Evaluating the Potential of Container-Based Sanitation.”
4Dry cover material acts as a visual barrier, smell reducer, and desiccant.
5BMGF. (2018). “Gender and the Sanitation Value Chain: A Review of the Evidence” and “Case Studies in Gender Integration: Sanitation Product and Service Delivery in Kenya.”
6EY and WSUP. (2017). “The World Can't Wait for Sewers.”
7EY. (2018). “Global Leaders in Household Container-Based Sanitation Services.”
8Combined WASH expenditures below 5% of household income are generally considered affordable.
9Sklar and Faustin. (2017). “Pit Latrines or Container Based Toilets?”
10Founder members of the CBSA include Clean Team (Ghana), Loowatt (Madagascar), Sanergy and Sanivation (Kenya), SOIL (Haiti) and X-Runner (Peru). Additional CBSA members and affiliates: Sanitation First (India) and Mosan (Guatemala). Additional CBS organizations: Fundación Sumaj Huasi (Bolivia) and Non-Water Sanitation (India).
11WHO. (2016). “Sanitation Safety Planning.”
12The VUNA project was a collaboration of EAWAG and municipality of eThekwini in South Africa (
13UN-Habitat. (2010). “The Challenge of Slums.”