*ZIMSEC Combined Science Project* on the theme of *Natural Water Purification*,
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*ZIMSEC Combined Science Project: Natural Water Purification Methods*
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*Stage 1: Problem Identification*
*Problem Description:*
In rural areas of Zimbabwe, access to clean and safe drinking water is a significant challenge. Many
communities depend on water from unprotected sources such as rivers, wells, and ponds, which may be
contaminated with bacteria, parasites, and other harmful microorganisms. This contaminated water is a
major contributor to waterborne diseases like cholera, dysentery, and typhoid. Traditional water
purification methods, such as boiling, may not be easily accessible or affordable, leaving these
communities at risk. Therefore, there is a need to identify and evaluate natural, cost-effective water
purification methods that can be used by people in these rural areas.
*Statement of Intent:* This project aims to explore and evaluate the effectiveness of natural water
purification methods using locally available materials like sand, charcoal, and gravel. By investigating
their ability to filter and purify contaminated water, the project seeks to identify sustainable and
affordable solutions for providing clean water to communities without reliable access to formal water
treatment systems.
*Main Idea / Theme:*
The focus of this project is to construct simple, natural water filtration systems using materials like sand,
charcoal, and gravel, and assess their ability to remove contaminants from polluted water sources. The
project will involve setting up various filtration systems and testing the quality of the filtered water using
basic indicators like clarity, color, odor, and the presence of visible particles.
*Design Specifications:*
1. *Materials:* Use natural, locally available materials like sand, charcoal, and gravel to construct
filtration units.
2. *Contaminated Water:* Use water samples from local unprotected water sources (e.g., rivers or
ponds) that are known to be contaminated.
3. *Filtration Systems:* Construct simple filtration devices using empty plastic bottles, and fill them with
layers of sand, charcoal, and gravel. Each layer will act as a filter to trap different types of impurities.
4. *Testing:* Test the water before and after filtration for visible particles, clarity, and odor. Compare
the effectiveness of different types of filtration systems using these parameters.
5. *Safety Considerations:* All safety guidelines must be followed while handling contaminated water.
Proper disposal methods for waste and used materials must be implemented.
*Relevance to the Community:*
By investigating the effectiveness of natural water purification methods, this project aims to provide
practical, cost-effective solutions that can be implemented by communities facing challenges in
accessing clean water. If successful, these methods could help reduce the prevalence of waterborne
diseases and improve public health in rural areas.
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*Stage 2: Investigation of Related Ideas*
*Research and Data Collection:*
To better understand natural water purification methods, the following sources of information were
reviewed:
*Books and Scientific Articles:* Information on water purification techniques, especially using natural
materials, was gathered from books on environmental science, public health, and chemistry.
- *Previous Studies and Articles:* Research on natural filtration using materials like sand, charcoal, and
gravel was reviewed. Studies have shown that these materials can filter out large particles and absorb
impurities like bacteria and chemicals.
- *Community Practices:* It was noted that many rural communities in Zimbabwe use sand and charcoal
to filter water before use. However, the efficiency of these methods is not well documented.
*Related Techniques:*
- *Boiling:* Boiling water is a common method to kill microorganisms, but it may not be feasible in areas
without access to cooking fuel.
- *Chemical Purification:* Chemical purifiers like chlorine are often used in urban settings but may be
too expensive for rural communities.
- *Filtration with Sand and Charcoal:* This is an affordable and widely used method in many developing
countries, but the exact effectiveness of such methods needs to be tested.
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*Stage 3: Generation of Ideas*
*Possible Solutions:*
Several ideas were generated for the project
1. *Sand Filtration:* Using sand to filter out large particles from contaminated water.
2. *Charcoal Filtration:* Activated charcoal can adsorb chemical impurities and improve water clarity.
3. *Combination of Sand and Charcoal:* A two-layer filtration system where sand filters out larger
particles, and charcoal removes chemical impurities and odors.
4. *Gravel Filtration:* Gravel can be used as a pre-filter to remove very large particles before finer
materials like sand and charcoal are used.
*Testing and Analysis:*
Each of these ideas will be tested to determine which is most effective at purifying the contaminated
water. Different combinations of materials will be used to create various filtration systems, and their
effectiveness will be compared.
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*Stage 4: Development of Ideas*
*Chosen Method:*
After considering the different filtration options, it was decided to proceed with the following filtration
setup:
- *Three-layer filtration:* The filtration unit will consist of three layers:
1. *Gravel* at the bottom to trap large particles.
2. *Sand* in the middle to filter smaller particles.
3. *Activated charcoal* at the top to absorb chemical impurities and improve taste and odor.
The filtration unit will be constructed using an empty plastic bottle with the bottom cut off, allowing the
water to flow through the materials. This setup will be tested on water samples taken from local
sources.
*Testing the Results:*
- *Clarity Test:* Observing whether the water becomes clearer after filtration.
- *Odor Test:* Checking if the odor of the water is reduced after filtration.
- *Visible Impurities:* Noting any visible impurities that remain in the water after filtration.
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*Stage 5: Presentation of Results*
*Results Summary:*
After testing each filtration system, the results were as follows:
- *Before Filtration:* The water from the river was visibly dirty, with suspended particles and a strong
odor.
- *After Filtration:*
- *Sand and Gravel Filtration:* The water became clearer but still contained some visible particles.
- *Charcoal Filtration:* The water had reduced odor, but clarity was not greatly improved.
- *Three-Layer Filtration (Gravel, Sand, Charcoal):* This filtration system was the most effective,
producing clear, less odorous water.
*Graphical Representation:*
Data on the clarity, odor, and visible impurities were represented in bar graphs to show the relative
effectiveness of each filtration system.
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*Stage 6: Evaluation and Recommendations*
*Achievements:*
- A simple, affordable water filtration system using natural materials was designed and tested.
- The three-layer filtration system was found to be the most effective in improving water clarity and
reducing odor.
*Challenges:*
- The filtration did not completely purify the water, as some bacteria and microorganisms may still have
been present.
- The process was time-consuming, especially for large volumes of water.
*Recommendations:*
- *Further Testing:* Further experiments should be conducted to test the microbial contamination in the
filtered water using a water testing kit.
- *Additional Materials:* Consider incorporating other materials such as cloth or ceramic filters to
further improve water quality.
- *Community Implementation:* These filtration systems can be introduced to rural communities as an
affordable, sustainable method for improving water quality. Training should be provided to ensure
correct use.
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