2.1 Equipment List
Beakers (250 ml)
Electronic Weighing machine
Fecal Coliform Bacteria Testing Kit
40m of rope
Rolls of Masking Tape
Heat-safe gloves / Tongs / Towels
Plastic bottles (300ml)
Fig 1: Diagram of experimental setup
Fig 2: Diagram for Procedure for testing Dissolved Oxygen
Fig 3: Diagram of Procedure for testing of Sediments
Fig 4: Diagram of Procedure of testing for Fecal Coliform Bacteria
- Setting up:
- Use Buckets and rope to collect water from a fixed location (eg. The canal in Sungei Ulu Pandan)
- Set up 4 identical tanks with ¾ of the tank filled with the water collected each.
- Set up an aerator in the same fixed position in each tank.
- Label 2 tanks A1, A2 and plant 6 water hyacinths in each tank.
- Label the 2 other tanks B1,B2 (these would be the control-tanks without the Water Hyacinth)
- Testing for Dissolved Oxygen (DO) Saturation:
- Collect 100 ml of water from each of the 4 tanks using one of the beakers
- Ensure each sample is properly labelled using the markers and masking tape before testing (e.g Day 1 A1 Sample )
- Turn the DO probe on and leave it to warm up in deionised water for 10 minutes
- Place it into the bottle of Sodium Sulfite Solution and wait for it to stabilise.
- Place the tip of the probe into the container with 1 millilitre of the sample till it stabilises.
- Place the tip of the probe (indicated on the device) into the water
- Gently stir the probe and monitor the dissolved oxygen concentration
- Record findings in LogBook
- Repeat steps 1-8 with 3 other samples
- Testing for the amount of Sediment:
- Collect 100 ml of water from each of the 4 tanks using the beakers
- Label each Sample properly using the markers and tape. ( e.g Day A1 Sample)
- Weigh the weight of the beaker and the weight of the beaker with the water sample using the electronic weighing machine.
- Subtract the weight of the beaker from the weight of the beaker with the water sample to get the weight of the water sample and record result in LogBook in grams.
- Turn on electrical hotplate
- Place beaker on electrical hotplate
- Let all water boil and evaporate leaving behind the sediment and other dissolved solids in the water
- Once beaker has cooled, place the sediments onto the weighing scale
- Record the weight of the sediment in the LogBook next to the weight of the 100 ml water sample and the sample name.
- Repeat steps 1-9 with 3 other samples
- Testing for Fecal Coliform Bacteria
- Obtain 6 47mm Sterile Petri dishes.
- Ensure each petri dish is properly labelled before testing (e.g Day 1 A1 Sample )
- Using an ampoule beaker, open and pour 1 ampoule of mFC/Rosolic Acid Broth into each petri dish.
- Place the lids of the petri dishes back on and discard the empty ampoules and any extra Acid Broth.
- Remove the top of the filtration unit. Using sterilised forceps, carefully place a membrane filter onto the filter and pour a small amount of deionised water onto the filter to help seal it.
- Filter the 10 ml sample by pouring the sample into the apparatus. Be careful to avoid pouring the sample on the inside walls of the filtration apparatus.
- Suction the sample through the filter by squeezing the hand pump a couple of times to create a vacuum. Make sure most of the sample flows through the filter and does not remain in the filtration apparatus. When all the water is through the filter, stop pumping and break the vacuum.
- Rinse the filtration unit with 3 different 30ml portions of deionised water.
- Sterilise the forceps by dipping them in an alcohol like ethanol and passing them through a flame.
- Allow the forceps to cool before continuing.
- Carefully remove the filter with sterilized forceps and place the filter grid side up on the medium in the proper, labelled petri dish. If there are any air pockets between the filter and the medium carefully tap the filter down with the forceps.
- Place lid back on petri dish and keep each petri dish until you are ready to incubate.
- Stack petri dishes upside down and incubate them for 24h at 44.5 degrees celsius.
- After incubation, count the fecal coliform bacteria colonies that are on each filter. Each bluish spot would be a fecal coliform colony. Cream, gray and other colonies of other colours should not be included as they are not fecal coliform bacteria colonies.
- Divide the amount of colonies counted by the ml filtered(10 ml) and multiply that number by a 100 to get your result for the sample in CFU( Colony Forming Units)
- Record them into the LogBook ( Day 1 A1 Sample -> 60 CFU)
- Repeat steps 2-16 to all samples.
2.4 Risk Assessment and Management
The water has not been treated and therefore is not safe to drink.If consumed in large amounts, it might cause stomach flu and other sicknesses
-Must be careful.
-Do not speak while collecting water or when around moving water.
-Washing hands after experiments
We might fall into the canal when collecting water
-Do not play around the canals
-Make sure to be careful when collecting water
-Be alert of environment
-Always have at least one other person to be around when collecting water
We could burn ourselves from the flame of the bunsen burner or the hot boiling water on the wire mesh.
-Do not play around the fire or water
-Be alert of environment
-Leave items to cool before touching them
-Wear Eye goggles
-Use heat Safe gloves/ tongs when dealing with the hot beaker
As the experiment involves glassware, there is a risk of breakage and cutting of the hands.
Wear gloves when carrying out the experiment. In case of breakage, the cut to the hands will be minimized.
Unlikely and not severe harm
Likely but not severe OR Unlikely but severe
Likely and Severe harm
- Things to Note:
Due to protocol in the Van Cleef Research Centre, Wear a lab coat while using the equipment in their facility.