2. Methods

Equipment list:
  • 1 Water hand pump (optional,without it water flowing through the filter will be slower)
  • 1 beaker
  • 1 Kg of sand,
  • 1 Kg of  pebbles,
  • 2 dried durian husk cut into cubes
  • 3 dried lemon skins cut into smaller pieces of at least 1 cm by 1 cm
  • 1 Kg charcoal
  • 3 dried Banana peels (in case)
  • 1 Kg of gravel (Size around 1cm x 1cm)
  • 1 Acrylic tube of 100 cm long, 3.5 cm in diameter ,0.2cm thickness
  • 1 Acrylic tube of 18 cm long, 1 cm in diameter
  • 1 Acrylic plate of at least 4 cm by 12 cm
  • 500g of Activated Carbon
  • 8 petri dishes containing nutrient agar
  • 8 plastic spreaders (for each petri dish)
  • Cellophane tape
  • Marker to label
  • Incubator
  • Micropipette and tips
  • 3 small plastic test tubes

Diagrams
*The materials must be fitted completely & fully into each sections.

Design 1
Pebbles-->Gravel-->Charcoal
Activated Carbon-->Durian husk-->Coarse sand-->Fine sand

Design 2
Pebbles-->Gravel-->Charcoal
Activated Carbon-->Durian husk-->Lemon skin-->Coarse sand-->Fine sand
 
Design 3
Pebbles-->Gravel-->Charcoal
Activated Carbon-->Durian husk-->Lemon skin-->Banana Skin-->Coarse sand-->Fine sand
Best Solution and Reason :
As bananas are easy to rot which can cause the result to be full of bacteria, and by adding it into the tube ,it may cause the water flow to be very slow,the bananas acts the same way as the durian husk too while the lemons that was added to design 2 was used to kill some bacteria. By using lesser stuff water would be easy to flow so that we can improve its filtration properties while reducing the amount of stuff.
Procedures: Detail all procedures and experimental design to be used for data collection
(To be repeated 3 times)
1.First, Get all the equipments stated above in the equipment list.

2.Secondly, Cut the big acrylic tube into 2 equal parts

3.Cut the acrylic plate into the diameter of the 2 big acrylic tubes,and make a hole in the middle for the small acrylic tube to fit in.

4.Measure the amount of each components freely but equally.(Ensure that the amount of items allows the water to pass through when pumped)

5.Fill up the tube with the necessary items based on the picture below.

6.Fit the small acrylic tube into the acrylic plate half way through and glue it tightly.Then, fit it into the big acrylic tube’s opening and glue it tightly.

7.Connect the pump to the tube.

**8.Pump the pond water in and collect the water using the plastic test tubes.
Bacteria Cultivation Steps:

9.  First place 1 micro litre of water into an agar plate and spread them with spreaders

How to spread the water with spreaders:

Spread the bacteria following the arrows on the diagram until the whole agar plate is covered.





10. Place them in the incubator for 24 hours at 37 degrees

11. Count the number of bacteria colonies by using marker to mark each colonies.

12. Record the results down in a paper (Using the table below) and observe the results.

**Pumping of water (Steps):

1. Use the pump to pump water through the filter while placing it near the sink to prevent spillage

2. Repeat the first step to further filter the water

3. Compare the filtered water by cultivating bacteria and counting the no. of bacteria

Risk and Safety: Identify any potential risks and safety precautions to be taken.
The Durians' spikes are sharp and can hurt us when cutting it, while using the other fruits like lemons and bananas we need to seek adults help and also, we must use safety gloves as knives are sharp.
The saw used to cut the tube is sharp ,it may cut our hand off when cutting it ,it is important to use it safely and not play around with it.
The environment of the place where we dry our fruits must be dry to prevent the fruits from rotting if not, bacteria might grow on it which is a biohazard.
Data analysis:

For the unfiltered petri dish,we found out that it had fewer number of bacteria colonies,but some of the colonies were much bigger than the others,and the colonies also vary in colour,like white and yellow.For all the filtered petri dishes,there were a lot of small colonies,but there are higher number of colonies, with an average colony count of 120.The colonies might not be bacteria,but wild yeast as they grow rapidly on durian husks. We also found out that pondwater contains a huge amount of Escherichia coli (E. coli) and since the fruit itself is antibacterial,its properties have been transferred to the husk.We do not have an electric field gradient,which is used in seeing whether a bacteria is good or bad,therefore we conclude that the filtered water is safe for consumption,as most of the bacteria in it is good.


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