Container-based sanitation

A portable urine-diverting dry toilet as marketed by SOIL in Haiti under the name of "EkoLakay"

Container-based sanitation (CBS) (or cartridge-based sanitation) refers to a sanitation system where human excreta is collected in sealable, removable containers (also called cartridges) that are transported to treatment facilities. Container-based sanitation is usually provided as a service involving provision of toilets, usually dry portable toilets, and collection of excreta at a cost borne by the users. The system incorporates measures to isolate excreta from human contact throughout the sanitation chain (i.e. during containment, emptying, transportation, treatment and disposal or reuse of excreta).

Its main application is for situations where alternative options that rely either on a sewerage system or on a hole in the ground (pit latrine) are not feasible. CBS is sometimes done in informal settlements in cities of developing countries.

The "cassette toilets" used in motorhomes have a similar concept but are usually a type of small chemical toilet.

Background

The world's population is urbanising at a pace that outstrips existing infrastructure and municipal capabilities, making society's ability to meet Sustainable Development Goals (SDGs) increasingly challenging. There is a need for an alternative sanitation option where on-site sanitation and sewerage are not feasible. Container-Based Sanitation (CBS) refers to a system where excreta is collected in sealable, removable cartridges that are transported to treatment facilities. Container-based sanitation is usually provided as a service involving provision of certain types of portable toilets, and collection of excreta at a cost borne by the users. Examples of organizations that provide this service are Loowatt in Madagascar, Clean Team in Ghana, X-Runner in Peru, and SOIL in Haiti.

CBS as a model is a viable solution to address issues of urbanization and improved sanitation (especially considering Sustainable Development Goal Number 6 "Ensure availability and sustainable management of water and sanitation for all"). The different operators of CBS systems have developed their own approaches and business models that currently have differing levels of scale. However, with suitable development, support and functioning partnerships, CBS can be used to provide low-income urban populations with safe collection, transport and treatment of excrement at a lower cost than installing and maintaining sewers.

Description of components

The latest version of SOIL's EkoLakay container-based toilet.

A CBS system includes a toilet (usually portable) with a removable container which is routinely exchanged for an empty container when it is full. The toilet design, which may incorporate the use of chemicals and a biodegradable plastic film, in the case of Loowatt, eliminates human contact with faeces and reduces odor and insects. All infrastructure associated with a CBS system is typically situated above ground, thereby reducing both construction costs  and vulnerability to flooding. Excreta-filled containers are sealed and transported to a designated disposal or composting site. Water needs are limited to the amount required for anal cleansing and hand washing.

CBS systems are typically waterless and in most cases (with the exception of Loowatt), a urine-diverting dry toilet is used, since they are simple and the volume containing the potentially infectious feces is kept small and manageable. The urine is drained into the soil or used as plant fertilizer with less need for treatment. One of the main advantages of CBS is that treatment of feces is carefully performed at a central location and its effectiveness can be easily monitored.

Costs

Typically, a CBS system would represent a substantially lower initial investment (usually a deposit equivalent to the monthly service fee) compared to the cost of construction of a latrine or pour flush toilet. For example, the Clean Team in Ghana provides the service of collecting the waste at a cost equivalent to about 9 USD a month for up to five users with no capital expenditure on purchasing the toilet.

In the case of SOIL in Haiti, the costs were reported in 2016 as follows: Monthly cost of the service for a household is approximately 20 USD (including toilet provision, transport and waste treatment). The customers pay a 4-5 USD monthly service fee. SOIL has an income from compost sales per household of about 1.60 USD per month. This means SOIL is currently able to cover an estimated 30% of the overall costs of the sanitation service, including toilet provision, transport and waste treatment.

It is expected that for the business to succeed, the toilet should cost no more than US$ 40 to 50 toilet and have at least a 5-year life span.

Opportunities

Public private partnerships

Scaling up container-based sanitation models is expected to be easier by using public private partnerships (PPPs). In such a system, the CBS company would enter into a contract directly with the local authorities to instal and maintain toilets, and managing excreta collection for entire communities, in return for a monthly service fee. The advantages of this approach are higher customer densities, more straightforward and reliable revenue streams, and reduced customer acquisition and capital costs.

Challenges

Safety of emptying operations

The feces collected in CBS are often treated in compost bins like this one.

The underlying principles of a CBS system can bring to mind related, but quite different models of excreta management such as composting toilets or bucket toilets. The latter are sometimes emptied in an unsafe manner referred to in India as "manual scavenging". The CBS system does share with a bucket toilet the feature of manual collection of excreta in a relatively small container. However, the CBS system incorporates measures to isolate excreta from human contact throughout the sanitation chain (i.e. containment, emptying, transportation, treatment and disposal or reuse).

The CBS system has received opposition due to its resemblance to unsafe and banned systems, like manual scavenging. The system is still in its early stages and is yet to gain official recognition in many regions as a safe alternative to sewers and on-site sanitation systems. In order to gain recognition and operate in some regions like India where manual scavenging is unlawful, the systems had to demonstrate their capacity for sustainable growth, replication and to prove its benefits to public health and local economies, when applied at a large scale.

Subsidies

Container-based sanitation systems often still need subsidies, as do many other sanitation systems.

Examples

Schematic showing how container-based sanitation achieves hygienic and productive recycling of feces

Even though the basic concept of the CBS system has been applied by various organizations and businesses that provide this service, there are a few differences mainly in the types of toilet interfaces used, financing models, and reuse or disposal.

Sanitation First (GroSan Toilets)

The toilet interface used is that of a urine diverting dry toilet (UDDT). Within the toilet superstructures are two spaces: one for the UDDT toilet and another for anal cleansing with water. Underneath, containers receive separately the three types of excreta: feces, urine, and anal wash water. Once full, the containers are taken to a central treatment facility and others and put in their places.

SOIL

The non-profit organization SOIL was established in Haiti in 2006, seeking to prove that it is possible to sustainably provide affordable and dignified household sanitation services even in the world’s most under-resourced communities. In their simple social business design, feces collected in locally made, urine-diversion container toilets (branded as “EkoLakay” in the local language) are transported to a composting facility, where they are safely transformed into agricultural-grade compost. This compost is then sold for agricultural application, improving both the fertility and water-holding capacity of local soils. Revenue from monthly user fees and compost sales are used to cover a part of the ongoing project costs. This project shows the potential for private sector involvement in the provision of affordable and sustainable sanitation services in the world’s most impoverished and water-scarce communities.

Clean team

Clean team is a sanitation business currently being piloted by Water and Sanitation for the Urban Poor (WSUP) in Kumasi, Ghana. It began its operation in 2011 as a joint venture between WSUP and Unilever. One of the main components of Clean Team is a custom designed toilet which is used inside the homes of the users. The clean team provides the toilets to users at no initial cost. There is however a weekly or monthly charge paid by customers for the service of collection of containers filled with excreta and replacing the containers.

See also

• Decentralized wastewater system
• Emergency sanitation
• Open defecation
• Self-supply of water and sanitation
• Sustainable Sanitation Alliance
• Ecological sanitation

External links

Wikipedia's health care articles can be viewed offline with the Medical Wikipedia app.

• Library of Sustainable Sanitation Alliance containing more documents on this topic