Week 3 - CLS Filtration Activity
Our third week of Engineering and Design was focused on Filtration of water.
We were tasked to create a filter to process wastewater. So there were some important steps and measures that had to be taken throughout the whole experiment.
We used the same measuring devices made by the other groups from the past weekly activities. Here are the links to them
1. pH Sensor
2. Conductivity sensor
3. Dissolved Oxygen Sensor
Our Hypothesis
If the dirty water passes though a 6cm sand filtration system, the pH will not change as there was no chemical reaction involved. The dissolved oxygen would remain the same as well.
Whereas the conductivity would decrease as impurities are being filtered through the sand and there would be cleaner water. Pure, distilled water has a bad electrical conductivity.
STEP 1 - Measure initial PH, Dissolved Oxygen and 02.
This step was important as it allows us to compare the data afterwards to see the changes.
STEP 2 - Build the water filtration device
The filtration device was really simple, we had to cut open a bottle and fill it with our filtration material, sand. However the sand had to be packed together closely to minimize the air gaps between the sand particles.
This is to allow the water to be better filtrated when the water passes through it.
STEP 3 - Filter the water through the sand filter
We had to repeat this process 3 times and record it down in a table. Here u can see the super murky and dirty water that we had poured into our filter.
And the water that comes out is much more cleaner! (even though its still not safe for consumption)
-> Our recorded table
Our thoughts after the experiment
Values for pH, conductivity and dissolved oxygen had definitely changed after the filtration process. One of the most important and drastic change was the conductivity. The conductivity decreased drastically from around 200 to 160.
We also noticed that the pH levels remained around in the same range of 6-7.
In addition the dissolved oxygen values also declined.
Comparing to our initial hypothesis which we had made before the start of this experiment, our assumption about the conductivity of the water before was correct but the pH and dissolved oxygen hypothesis was not.
Summary
We learnt how filtration works after this experiment as well as how the ingredients used for the filter and the filter bed height can affect the results after the experiment. Using our hypothesis method that we had learnt previously we were able to craft a hypothesis even though it was not totally accurate.
Written By : Clarence
