KASAFI Filter System

An adaptable and locally sustainable water filtration system for low income communities.

The Issue of Water

Within the Maasai community, water is an apparent and complicated issue. The lack of filtration practices and expendable income forms a dangerous cycle in which there is acknowledgement of a problem, but no accessible solution available. This project attempts to address this issue through the co-design of a culturally sensitive and locally sustainable filter.

Understanding the Culture

In order to design for a demographic, I first needed to understand the users and their culture. Secondary research as well as primary testimonies were gathered which highlighted customs, traditions, and cultural nuances.

A Risky Necessity

Water is a hard earned resource for the Maasai of Tanzania. Women spend many hours per day in search of water, and must walk many kilometres with 50+ pounds on their backs. This is potentially repeated multiple times per day, everyday. The water they collect is usually contaminated with microbacteria, which is a major culprit in the high infact mortality rates the Maasai face.

Exploring Filtration

Exploration was conducted in two major areas: Filtration technologies, and Filtration Facilitation. Many filtration technologies were examined, and those that were contextually appropriate were further investigated. It was identified that gravity filtration was the most cost effective and accessible solution. Specific studies on Cloth filtration revealed removal of 99% of cholera with 4-8 layers of cotton cloth. Carbon was another promising medium. Further research would need to be conducted.

Facilitation

It was noted during research that most existing filtration systems lacked a means of efficiently loading the water into the system, requiring the user to manually load the full weight of the water into the reservoir. This was seen as an opportunity for refinement and means of streamlined integration into the Maasai's currently water collection practices.

Usability tests were conducted with both male and female users of different heights. It was noted that for a 5'2" female user, there was notable difficulty in loading the barrel due to the height of the loading platform. Furthermore, there were stability issues due to a lack of support beams and the use of thin tubing. Further development would be needed. Filtration mediums were tested for their effectiveness and efficiency.

Various levels of prototypes were constructed to test a variety of factors in the design, both for the structure tests and filter effectiveness. These ranged from low fidelity scale models to full scale test models. Different loading techniques were prototyped, varying in mechanical complexity. It was noted that early iterations became complicated, and that by integrating the water carrying technique of the Maasai, water could simply be dropped off at the correct height. This lead to a stationary stand design that was then tested.

Prototyping and Testing

Tanzania

My classmates and I had the chance to travel to Longido, Tanzania in order to further understand the culture and environment we were designing for. With the help of Project TEMBO, we were able to have many experiences with the Maasai that ranged from traditional water collection, to one on one conversations with Maasai women to establish first hand context on their issues within the problem spaces we were designing for. 

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Underutilized Potential

While in Tanzania, we were also exposed to a large pool of skilled labour that, had I not visited Tanzania, would not have known about. Manufacturing, both in industrial and local contexts, were readily available and underutilized. In Arusha, SIDO was capable of a large variety of machining operations, while in a rural context, the Maasai women were highly skilled at sewing. Lastly, the community themselves were highly engaged and eager to co-develop design solutions. This brought new light to different design refinement opportunities. 

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Design Refinement

Upon returning from Tanzania, and with a new understanding of the culture and capabilities of manufacturing, I began design refinement. I refocused my efforts on creating a filter system with an accompanying structure. I began developing a robust filter system that consisted of a housing, as well as a replaceable filter bag. The idea was to make this fully within a local setting, and allow for the women to produce their own filter bag with the skills and materials available to them. This would allow promote self sustainability. The housings would be created in SIDO with simple machinery and labour.

Definitive Filter Design

The name Kasafi comes from the Swahili words Kaboni and Safi, meaning carbon and clean respectively. The final filter design attaches onto any modified container. A mesh pre-filter is included that friction interfaces with the main housing. The main filter component is a cloth carbon filter that is easily manufacturable in a local context. All of this fits into a simple package that also contains visual instructions for both filter changes and creation.

The main filter housing is comprised of four machined aluminum pieces, three of which thread together into an interfacing component, allowing for attachment onto any container. Design details such as stippled shaped recesses are used to visual indicate which pieces interface with one another. A funnel is attached to the bottom of the filter housing which directs the filtered water into the centre, and contains an NPT thread which interfaces with most water application parts. The filter bag is also lipped to easily fit over the ledge on which it interfaces and is pulled taut over.

Definitive Structure Design

The structure is a simple steel frame with a painted sheet metal basin and platform. Shearing and welding are the only two processes that are needed for manufacturing. As a result, the structure is highly repairable and is able to be produced easily. The height enables users to effortlessly transition from traditional water carrying methods, affording easy integration into their daily water collection routine.

The basin that holds the unfiltered water has a hole cut to allow for easy installation of the KASAFI filter. Below the basin is a platform that has a small lip that indicates where to place the empty barrel to be filled. A cloth sling allow the user to unload and suspend their full water barrel above the emptied water to avoid further contamination from the barrel's outer surface. A crossbar prevents the barrel from sliding forward into the filter and basin. 

Above is a video summarizing the filter system.

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© 2020 by Nathan Siu