Activity 5 : Water Treatment (Sedimentation and Filtration)

Activity 5 : Water Treatment (Sedimentation and Filtration)

We had done with the activity related to coagulation and flocculation during week 2 of our module.This week, we are doing the activity the other two water treatment process which are sedimentation and filtration.Before the lesson,we were instructed by our lecturer to watch the videos which uploaded by him to eduCanon.The videos gave us some ideas about what we will be doing during our lesson.

Filtration and Sedimentation

Our first activity is Sedimentation and below are the materials needed for our first activity.

Clear Water, Cooking oil, Small balls

First, we are required to calculate the settling velocity of the small ball in clear water and cooking oil using the formula below:

Here is our calculations:

After that, we start our activity to find out the experimental values of the 2 different situation. Due to the distance is needed to calculate the velocity, so we measure the length of the fluid contained in two bottle first before we start.

 

We put the small ball slowly to the oil and water and video recording the process using UberSense apps which we required to install it before our lesson. This app enable us to determine the time at which the small balls pass through each position by scrolling through the video.

Small ball passing through water 

Small ball passing through oil

We carry out the experiment twice in order to get more accurate results by calculating their average values.

Experimental results

Although that our experimental values are different with our theoretical values, but we can conclude that small ball travels faster in water than in cooking oil according to our experimental results. This is because the cooking oil is more viscous than the water.

Our second activity is to build an effective rapid water filter by using the materials given to our group: 

 

For our group, we are going to use gravel as our bottom (4 cm) and charcoal on top (3 cm).

After building our water filter, we need to clean our filter with about 1 litre of clean tap water before we pour in the dirty water.We are required to filter 3 water samples and each samples must be at least 100 ml.Due to the limitation of time, we need to shake our water filter slowly to increase the speed of its process in order to finish our experiment on time.

After getting the samples after filtration, we have to measure the turbidity, pH and conductivity of water before and after the filtration.

Measuring turbidity

Measuring pH

Measuring conductivity

This is the final result which we get from our filtration activity:

According to our results, it is quiet unexpected that our turbidity decreases because at first we think that it might be become more dirty because of the charcoal.However, we know that the first step, which is rinse our filter with tap water had greatly reduces the impurities of our filter system after our discussion. Besides that, the pH of water after filtration had increase about 3 because the charcoal is alkaline.

From these two activity, we learnt more about sedimentation and filtration. We also learnt about how to get a clean water and build water filter system. However, although the filtered water is clean, but it is still not suitable for drinking because it contains bacteria and microorganism which cannot be filter.

That's all for our this week's activities. Thank you for reading.