Below is our groups blog post WITHOUT any photos embedded. Here we have attatched a PDF of our full blog post WITH photos embedded. BlogPost.pdf

WATER FILTRATION - Blog Post

By Steve Hatzipavlis, Massimo Marchese, Vincent Burkitt-Doyle and Nicholas Peppercorn

Introduction/Rationale

One of the great struggles of contemporary times in regards to increasing development in developing countries, is finding easy methods by which to purify water. Water, a necessity for human life, is important in regards to health, and this has an impact on all other levels of human development including economic well-being, but the demand for drinkable water also results in many political tensions. Approximately 80% of all illnesses in developing countries are caused by poor water and sanitation conditions. Most water problems in the world, rather than being as a result of physical water scarcity, meaning that there is a lack in quantity of water, are largely as a result of economic water scarcity, meaning there is a lack in quality of water. Thus our group thought it was of utmost importance to find methods of purifying water through the use methods that could involve recyclable materials or even things you could find outside in nature in order to purify water.

In developing countries, some of the major contaminants in water include metals, bacteria, viruses, parasites and organic matter. Thus our group decided to focus on how our purifier could reduce a few of these contaminants. In a lab environment, the easiest of these was the presence of organic matter, as this could be achieved by boiling water off and measuring the remaining sediment. To test for bacteria, one of the most effective ways is by using an inoculating loop and putting samples of the purified water on agar jelly in a petri dish, and allowing it to incubate overnight. Therefore, though we would purify water to an extent, not all contaminants could be tested for, and thus our filtration system would remain merely a model. The rationale for the experiment is to see to what extent the water could be purified through these methods, rather than creating a device that could be used. But, from what we discovered, there are definite possibilities to explore methods by which to turn poor quality water, into drinkable water.

Prior to Experimentation

Before the two days of the project, our group collaborated through research to determine possibilities of experiments to perform. To suit the theme of ‘Use what you’ve got to make the world a little better’, we identified a need within the developing world that we could possibly attempt to solve. That need was for clear, drinkable water. Therefore, we decided to perform research to identify possible ways to filter water, in order to convert unsanitary water to possible drinking water.

During the research process, we visited a number of sources to try to determine what possible ways we could potentially filter contaminated water. Whilst researching, we took into consideration that the filtration system must only be made from household/recyclable materials under a budget of $20. This is because in many developing nations, certain resources are not always available. During research, we found many methods, however the most appealing method involved the use of materials commonly found worldwide. The materials used in this method included:

  • Twigs
  • Gravel
  • Sand
  • Charcoal
  • Pebbles

In this method, the materials would be stacked on top of each other as shown in the image below. Water would pass through each of these compacted layers, and gradually the larger particle sizes would be filtered out with each layer. This meant that by the time that water would be collected, all dirt, gravel and other materials would be left behind to produce possible drinking water. To replicate this filtration system we decided to use plastic bottles that you would find around the house (eg. milk cartons) to store the material.

During the research process we also discovered the possibility of using different forms of paper to filter water. Specially designed filter paper is an assured way of filtering water from a large variety of compositions, however this resource is relatively expensive and not available worldwide. We decided that testing alternative forms of paper that are easier to obtain would be useful, and compare these results to the filtration system above to determine what method of filtration would be the best possible. This way, we attempt a variety of different forms of filtration systems to determine which is the best possible.

Finally, we also thought about modelling the effect of the sun on our samples, and this would be achieved through a UV light. We did this because we knew our purified water wouldn’t be completely sterilised, and thus we wanted to see if our non-sterilised but filtered water could be sterilised through simply leaving out in the sun.

Method - Day 1/Day 2

  1. Went around the school grounds and gathered necessary materials for filter
    • Pebbles
    • Sand
    • Charcoal
    • Gravel
    • Twigs
  2. Made ‘dirty water’ to test using 5 handfuls of dirt, and water
  3. Constructed our filter in a plastic water bottle
    • Placed water bottle upside down
    • Cut the bottom off the bottle (now at the top since it was upside down)
    • Drilled a hole in the lid for filtered water to come out of
    • Constructed filter starting with twigs at the bottom (closest to the lid) followed by gravel, sand, charcoal, another layer of sand, and finally pebbles
  4. Placed a beaker underneath the bottle and poured the dirty water in the top
  5. Repeated for a few times to get the initial dirt out of the filter, until water started coming out relatively clear
  6. Tried again with paper towel stuck to the lid to help have a last layer of filtering
  7. Recorded our results

We were pleasantly surprised by the results of the first filter, as the water had changed dramatically in colour from very murky brown to clear with a tint of yellow. But we decided to see if we could make another filter, separating the different layers with paper, because we noticed on the first filter that many of the layers simply became mixed together

  1. Made second filter with filter paper separating each stage and with filter paper and paper towel stuck to the lid to help provide even more filtration
  2. Recorded our results

The results from this filter were even clearer than our first filter, but then our group became unsure about whether any of the layers were actually assisting in the filtration, and we hypothesised that maybe the paper towel we were providing on the bottom of the filter was doing the majority of the filtration

  1. Made a third filter with packed down paper towels
  2. Recorded our results

We discovered that we had hypothesised correctly and that the clearest water did come from our third filter only using paper towels, but to verify this, we decided to boil off some of the purified water samples from each of the filtration systems

  1. Took all samples from all filters and boiled off the water to weigh the amount of physical matter left inside

We also decided to use these same samples to try and grow some bacteria on agar plates to see if the purification had any effect on the bacterial levels in the water. But we made two agar plate samples for each, one which would also be hit by UV light, to see if we could model the sun’s rays and see if our purified water could be sterilised by leaving it out in the sun

  1. Swabbed different samples from different filters (using the same strokes for each sample) and spread onto two agar plates using a sterilised inoculating loop
  2. Used a UV light on one of the samples of each filter system, in order to model sterilisation by  leaving out to the sun
  3. Placed agar plates into incubator

We noted at the end of the first day that the paper towel would have bleach in it and is not made from 100% recyclable products and is thus not sustainable, and thus we decided to see if the filtration process through paper towels could also be achieved through products that could be used in developing countries

  1. Bought 100% recycled paper towel, and 100% natural and sustainable bamboo paper towel
  2. Made two more filters with the 100% recycled paper towel, and 100% natural and sustainable bamboo paper towel
  3. Recorded our results

Results

Collection of Different Tests Performed

Test Description

Image of Test

Test Description

Image of Test

Test Description

Image of Test

Filter #1 (First Attempt, No paper towel)

 

Filter #2 (First Attempt, no paper towel)

 

Filter #3 (First Attempt, only paper towels)

 

Filter #1 (Second Attempt, No paper towel)

 

Filter #2 (Second Attempt, with paper towel)

 

Filter #3 (Second Attempt, only paper towels)

 

Filter #1 (Third Attempt, With paper towel)

 

Filter #3 (Third Attempt, bamboo paper)

 

Filter #3 (Fourth Attempt, recycled paper)

 

The Percentage Sediment in our filtered water

Filter Number and Test Description

Weight of Beaker (g)

Weight of Water and Sediment (g)

Weight of Test Before Boiling (Beaker, Water and Sediment) (g)

Weight of Sediment (after boiling) (g)

Percentage of water and sediment with sediment (%)

Image of Test After Boiling

Filter 1 (first attempt, no paper towel)

98.68

125.14

223.82

1.32

1.05

 

Filter 1 (second attempt, with paper towel)

49.16

48.01

97.17

0.17

0.35

 

Filter 1 (third attempt, with paper towel)

100.22

57.05

157.27

0.34

0.59

 

Filter 2 (no paper towel)

104.59

77.42

182.01

0.21

0.27

 

Filter 3 (just paper towels)

117.83

204.87

322.70

0.12

0.05

 

Bacterial Spore Growths from Different Tests

Filter Number and Test Description

Number of large spore growths

Image of Test

Soil Water

>100*

 

Soil Water (UV light)

>100*

 

Filter 1 (third attempt) with paper towel

41

 

Filter 1 (third attempt) with paper towel (UV light)

58

 

Filter 2 with paper towel

28

 

Filter 2 with paper towel (UV light)

21

 

Filter 3 with paper towel

24

 

Filter 3 with paper towel (UV light)

14

 

*Both had too much growth to be measured (over 100 spores)

Analysis and Evaluation

Measuring the weight of the sediment remaining, having boiled off the water, it was found unsurprisingly that the water that appeared murkier and less clear had a greater amount of sediment left over. The “Filter 1 (first attempt, no paper towel)” had the most sediment left over, 1.32 grams, which was 1.05% of water and sediment with sediment. This attempt was also the murkiest (as seen in the photo provided). We concluded that this was the case because the filter had loose materials and sediment that needed to be washed out. The second attempt was less murky and the attempt after that was even less so. By the third attempt of the filter the loose materials had been mostly washed out and was working to its potential.

However the water being filtered out was still fairly clouded with dirt, so we decided to stick a folded paper towel, with sticky tape, over the opening at the neck of the bottle. When filtering water through this we found the water was much clearer but still had a heavy yellow tinge. When boiling off the water from this attempt, “Filter 1 (second attempt, with paper towel)”, 0.17 grams of sediment was left over, which was 0.35% of water and sediment with sediment. This was a substantial 300% decrease from the attempt without a paper towel.

Having finished this filter we decided to make a second filter. This filter we decided was going to have a piece of paper towel between each layer of material. We hoped this would greatly improve our water purity and remove some of the yellow tinge that was present. Boiling off the water, less sediment remained than when we used the previous filter. There was 0.21 grams of sediment remaining in the beaker after the water was boiled, which was 0.27% of what was in the water and sediment mixture. This method produced the least murky mixture so far, however we believed we could do better.

Noticing how much the paper towels improved the purity of the water, we decided to make a entirely from a recycled bottle and paper towels. Pouring dirty water through this filter, we discovered that this produced the cleanest, clearest and purest water yet. The water filtered as transparent as water from a tap would be. However an overwhelming odour of dirt could be smelt from the water which was slightly off putting. When the boiled water filtered, there was 0.12 grams of sediment left in the bottom. However some of this dirt may have been the result of blunder or an anomaly in the experimental process. The sediment made up 0.05% of the total water and sediment mixture.

This was an effective technique of purifying water but the paper towels used were not sustainably sourced and were most likely obtained with a great deal of deforestation, which is not environmentally friendly. Taking this into account we came up with the solution of buying recycled paper and sustainable bamboo paper towels. The bamboo paper towels when used as a filter produced an unsatisfactory slightly yellow result. The recycled paper towels, which were cheaper at $2.50, worked much better and the water produced was the same colour as the original unsustainably sourced paper towels. The most effective, sustainable, and cheapest way of filtrating water is through the use of recycled paper towels.

In regards to the agar plates, we found that the water sample from the paper towel filtration system was the least plagued by spores of bacteria growth, followed by second and then first filtration system. Evidently the sample with the most spores was the soil water which had over five times more spore growths than any other samples, proving that some of the bacteria was actually removed through the filtration process. In regards to the UV light ray though, there was no discernible link found between whether the UV light ray caused any sterilisation of the bacteria, and this was probably because they were only in the UV light for around 10 minutes, which mustn't have been long enough. The results here were not very reliable though, as there were not repeated experiments, and it was very hard to quantify the amount of bacterial growth. The UV light ray box may not have been able to effectively demonstrate the UV lights of the sun that could in effect sterilise any bacteria in the water.

Conclusion and Reflection

Therefore, our group can conclude that the filter that we created with paper towels inside was able to turn dirty, vile, and undrinkable water into clear, clean, drinkable water. We also discovered that it work best with the 100% recycled paper towels, as well as the environmentally friendly and sustainable 100% bamboo paper towels.

This method of purifying water would be able to provide a clean water solution to millions of people who go without a sustainable water solution every day. This also provides them with a solution that is easy to make, portable, cheap, reliable, and can be used hundreds of times before the need to replace it.

There is still the problem of bacteria that could be present in the water, but this could easily be fixed through simply letting the sun’s UV rays sterilise any bacteria in it over a few days, a method that has been shown to work, but that we have not been able to show in our experiment.

The group though is genuinely proud of the findings we found in the experiment, specifically how easy it is to make dirty water clean, and the fact that previous methods of having many layers of sand, pebbles etc. isn’t actually as effective as simply having a recycled piece of paper towel, which could be made from the pulps of a bamboo tree, or through recycling paper.