Members: Victoria Dilenian, Zach Sailer, Mary Brosnan, Matt Hoff, and Carrie Meagher.

Problem Statement

In Zanzibar, Tanzania there is a lack of clean water available, which causes health issues. We hope to address this problem by using sustainable methods and local resources.


Lack of access to clean water is a global problem. Water use has been growing at more than twice the rate of population growth in the last century. By 2025, 800 million people around the world will be living in countries with absolute water scarcity (meaning there is much less potable water available than there is a demand for) and 2/3 of the world population could be under stress conditions. Globally, diarrhea is the leading cause of illness and death, and 88% of diarrhea deaths are due to a lack of access to sanitation facilities together with inadequate availability of water for hygiene and unsafe drinking water. In developing countries, 70% of industrial wastes are dumped untreated into waters where they pollute the usable water supply. (1)

Why Choose Zanzibar, Tanzania?

There are several reasons why we chose Zanzibar as our specific location to address a water source issue. A member of our team has an uncle in Tanzania right now, so we have a contact there. He works with the Tanzanian government to help various communities throughout Tanzania with water purity issues. In Tanzania a weak corrupt government, mismanagement of resources, lack of education, and social problems lead to a serious problem of access to clean water. There is a Zanzibar Water Authority (ZAWA), however they have yet to make any real progress. Both the African Development Bank and UN-HABITAT have poured money and resources into the problem, but neither have been successful in making a lasting impact.

What each group has tried:

  • African Development Bank
    • Installing sewers to reduce the amount of contamination
    • Provide a loan/grant to ZAWA for them to use to help solve the problem
    • Implemented a rainwater harvesting system
    • Funded a project for alternative energy sources for lower cost of pumping water

However, none of these efforts have made any real difference to the problem in Zanzibar. While the details as to why are unclear, we suspect that this is because of a lack of communication and collaboration with the people of Zanzibar.

In Zanzibar there is a huge water disparity. There are huge hotels for tourists that have their own water lines and sewage system and then there is the rest of Zanzibar, where there are no sewage systems and the only access to water is by digging wells for access to ground water. However, because of the lack of a sewage system, the ground water is highly contaminated (70% of all water). Our team wishes to address this problem by suggesting a system that will filter the water and allow it to be stored. We chose not to address this problem by fixing the sewage problem for a couple of reasons. Fixing the sewage problem would be more costly and the ground water would still be contaminated for some time, so measures would still need to be taken to clean the water.

Entrance to the resort area, you can see the big difference between the area where the general population is and where the resorts are.

Water Contamination

Types of Common Water Borne Diseases Present in Their Water: (4,5)

  • Diarrhea – causes a person to lose both water and electrolytes, which leads to dehydration and, in some cases, to death.
  • Cholera – an acute bacterial infection of the intestinal tract. It causes severe attacks of diarrhea that, without treatment, can quickly lead to acute dehydration and death.
  • Hepatitis A – viral disease that interferes with the functioning of the liver; spread through consumption of food or water contaminated with fecal matter, principally in areas of poor sanitation.
  • Hepatitis E – Water-borne viral disease that interferes with the functioning of the liver; most commonly spread through fecal contamination of drinking water.
  • Typhoid fever – bacterial disease spread through contact with food or water contaminated by fecal matter or sewage.

How these pathogens spread:

  • spreads through feces contamination
  • wells contaminated by sewage leaking through sand
  • washing dishes/hands with unboiled/unfiltered water
  • washing fruits with unboiled/unfiltered water

What is Already Being Used

Current water storage situation in Zanzibar.

One of our members has an uncle currently in Tanzania working with the Tanzanian government on water sanitation projects in various communtities throughout the country. This is a list of things he told us he is currently using in Tanzania and the pros and cons of each method: (check out sources 2 and 3 for more information)

  • Boiling
    • Pros: everyone already knows how to use it
    • Cons: time, labor, and energy intensive
  • Dilute bleach
    • Pros: cheap, effective, has residual protection
    • Cons: has a distinctive taste and odor, can over or under use it, does not work well in turbid water
  • Chlorine tablets
    • Pros: cheap, effective, doesn’t smell, tablets are an exact amount so you can’t over or under use it, effective
    • Cons: has a taste, doesn’t work well in turbid water
  • Tulip filters (silver impregnated ceramic filters)
    • Pros: Doesn’t have a taste or odor, reduces turbidity, effective
    • Cons: Must be imported, expensive, slow
  • Ceramic pot filters
    • Pros: Doesn’t have a taste or odor, reduces turbidity, effective
    • Cons: expensive, slow
  • Carbon filtration
    • Pros: removes impurities and increases clarity, materials readily available
    • Cons: not as effective at removing pathogens
  • UV filtration (SODIS)
    • Pros: zero energy required, easy to maintain
    • Cons: bottles involved can be difficult to find, requires relatively clear water
  • PUR packets
    • Pros: packets have exact amount so you can’t over or under do it, uses flocculation so it reduces turbidity, residual protection
    • Cons: very expensive, has a taste
  • Biosand filters
    • Pros: effective, very inexpensive, easy to maintain
    • Cons: slow, large, must condition the sand beforehand

However, in Zanzibar the only commonly used purification method is boiling. When water is boiled correctly (bringing to a rolling boil for 2 minutes), this method can kill:

  • Cholera
  • Hepatitis A and Hepatitis E
  • Typhoid

Why is this not the best method? Boiling is:

  • time consuming
  • labor intensive (long distance to collect water, collect firewood, start & watch fire)
  • energy inefficient


What we aim to accomplish with our project:

  • Improve water sanitation and cleanliness for Zanzibar communities in a holistic manner.
  • Use natural and easy to access resources that are readily found on the island.
  • Provide education for Zanzibar communities on water contamination and how to build, use, and maintain filters.
  • Improve our knowledge of the global water situation through learning from the Zanzibar community.
  • Accomplish water sanitation, filtration, and education in such a way that the project can sustain itself after we have left.

The Plan: Technical

Our goal in this project is to specifically address and combat the common water borne diseases from above. The important thing to remember is that no process will ever be perfect, and any attempt to clean the water in Zanzibar is an improvement from their current conditions. Thus, we seek the most effective low-cost designs for eliminating pathogens and bacteria. Of the methods described above we decided to utilize carbon filtration and SODIS because of low cost, readily available resources, and effectiveness. Our plan take into account the rainy and dry seasons that Zanzibar experiences. During the dry seasons, community members will use water from the wells. They will purify it by first reducing the turbidity of the well water using carbon filters. Next the pathogens would be killed by using SODIS. Both methods are described in detail below. During the rainy seasons when there is plenty of pathogen free rain water, they will collect the water on their roofs using gutters and then store the water in the SODIS bottles.

Carbon Filters

How it works:

Carbon filtering is a method that uses pieces of activated carbon to remove contaminants and impurities, utilizing chemical adsorption.This method is usually a pre-treatment before other methods of purification is used when cleaning water. In our situation it will be used to reduce the turbidity of the well water before treatment with SODIS, becaues SODIS effectiveness is significantly reduced if the water is turbid. The carbon is activated by burning different carbon based materials (i.e. wood, coconut shells, etc.) into charcoal, grinding the charcoal to powder, and compressing it into the filtering funnel.

external image 800px-activated_carbon.jpg


  • Carbon materials are really cheap to obtain and are found all over the island. It is found in coconut shells, nutshells, wood, coal, etc.
  • Removes turbidity
  • While this method is not good for the environment, it is significantly less of an impact than burning wood to boil water everyday is


  • The activated carbon powder only lasts for roughly 150 liters of water filtration before it saturates and no longer purifies
  • This method absorbs contaminants, but cannot kill or remove bacteria and other pathogens

Solar Water Disinfection (SODIS)

external image SODIS.jpg

How it works:

SODIS uses plastic bottles to hold contaminated water. the bottles are then kept on a roof or other sunny spot and left for the appropriate amount of time. The UV rays from the sun damage the bacteria and other pathogens and render them incapable of reproducing, thereby purifying the water. The figure below describes the SODIS bottle method:

File:Pictograms SODIS.jpg
File:Pictograms SODIS.jpg

Picture taken from:


  • Sunlight is free! We have an unlimited source of ultra-violet rays from the sun, and thus, unlimited power to clear water.
  • All the supplies that are needed can be easily obtained in Zanzibar. It requires PET (Polyethylene Terephthalate) plastic, which is the plastic used in all common soda and water bottles.
  • This also provides a safe and sanitary way to store the water for long durations.
  • This method is highly effective during the sunny seasons of the year, and is very cost-effective. The only cost is to find one’s own bottles or other suitable storage containers, such as plastic bags.


  • It will require a large amount of bottles to supply a household. Thus, a family may need to collect bottles over time to have enough to store the water.
  • It is not effective during rainy seasons.
  • Another con is that SODIS does not help with water turbidity and very turbid water cannot be effectively cleaned by UV rays.

The table below shows the desired weather conditions for sanitation using SODIS

Weather Conditions Minimum Treatment Duration
Sunny (Less than 50% Cloud Coverage) 6 Hours
Cloudy (50% to 100% Cloud Coverage) 2 Days
Rainfall No Sanitation

The Plan: Social

This all comes down to proper education on the importance of sanitation and the cooperation of the community members. Without training in how to use the purification method and an education on how it can make a huge difference, the method is useless. Our plan is to include the community members in the education and implementation of our project: Here our the specific steps involved:

  1. Go to community leaders and get their support. Talk to them about different options (is our plan really the best way?) and whether they even want our help.
  2. With the support of the local leaders, go to the schools and local mosques for education programs and demo stations. Teach just how important sanitation is for good health and how filtration methods can help.
  3. Get the support of the resort owners to get access to their used bottles for use in SODIS.
  4. Continue community outreach to involve the entire community and train locals so that ownership of the program can be transferred and the project can continue after we have left.
  5. Involve a very small cost in order to increase ownership of the project for the locals.
  6. Approach ZAWA for their support and for the possibility of implementing our project elsewhere.

Things we would need to accomplish our goals:

  • Money from potential investors
  • Money for start up costs
  • Support of the local government (ZAWA)
  • Support of the local villagers
  • Establish a non-profit with the support of existing eater sanitation/purification organizations.
  • Approach current businesses in water filtration for suggestions and donations
  • Volunteers to help with education
  • Natural resources (carbon based materials)
  • Persuade hotels/tourist areas to donate empty plastic bottles for Sodis, and have donation bins for bottles

Concerns we have:

  • Getting the support of the resort owners as our source for plastic bottles.
  • Getting the community to support the project and understand the importance of sanitation.
  • Setting the project up in a sustainable way.

Stakeholders Analysis

Stakeholder Group Interests at stake in relation to project Effects of project on interests:

-1, 0, or +1

Stakeholder importance for project success:


Degree of influence of stakeholder:


Villagers Quality of water and health problems associated with unclean water +1 5 5
Resort Owners Effect on their water supply 2 2 3
Tourists Effect on their water supply 0 0 0
Zanzibar Water Authority (ZAWA) Effect on current methods of water filtration +1 5 5
Potential Investors Is this a good investment +1 4 3
Current water sanitation businesspeople Effect on business -1 3 2
Our group Success of project and our grade +1 5 4

Stakeholder Influence Importance of Stakeholder for project success
Unknown 1 2 3 4 5 (great)
Unknown Tourists
1 (none) Resort Owners
2 Current Water Sanitation Businesspeople
3 Potential Investors
5 (great) Villagers
Our group

Stage in Project Process Type of Participation
Communication (1 way flow) Communication (2 way flow) Collaboration (increasing control over decision making) Empowerment (control transfer for decisions and resources)
Identification Our group
Our group
Preparation and Appraisal Our group
Potential Investors
Implementation Villagers Our group
Supervision and Monitoring ZAWA
Evaluation Potential Investors HowZAWA

How This Project Has Affected Us

This project has affected us in many ways and changed our thinking on not only how to approach foreign aid but also about how we approach water sanitation here. Here are some ways in which the project has affected us:

  • It has increased our knowledge on just how dire the global water situation is and just how much we take our ready access to clean water for granted here.
  • It also has brought to light how energy inefficient our water purification methods are in the US. Maybe we should use some of these methods being used in developing countries here, instead of using harsh chemicals and energy intensive methods that we use now.
  • Helping a developing community is not about us teaching them, it is a mutual learning process.


(1) – global water statistics
(2) water purifying devices in developing countries
(3) purification options
(4) Unicef: Water, Sanitation, and Hygiene –
(5) Index Mundi: Tanzania Major Infectious Diseases –