Worksheet 2 – Determine the process adjustment / coagulation processes
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Name of Instructor
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What coagulants are used in your workplace?
What form of alum is used in your workplace, and what are its characteristics, for example
concentration and specific gravity in liquid form?
What is the average daily flow for your plant and what injection rates of alum are normally used
and at what times of the year? What happens in your workplace if a new dose rate exceeds the
current capability of the feeder/injector to deliver it?
Does your workplace have the ability to carry our jar tests, or do samples have to be sent away to
another lab for testing. What is the procedure in your workplace?
Worksheet 2 – Determine the process adjustment / coagulation processes
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Metal based coagulants leave a residual of metal in the water at the end of the sedimentation
process. What is the maximum permitted level of aluminium or iron in the water at the end of the
sedimentation stage of treatment for your plant?
Conduct two jar tests in your workplace:
1) Calculate the optimum dose of coagulant for a sample.
2) Test for the optimum pH level on the dose of coagulant from the first test.
Record your results using workplace forms or the template provided. Attach your results to this
worksheet.
Worksheet 2 – Determine the process adjustment / coagulation processes
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Jar Test
Operator
Source
Raw Water Data
Temp
Turbidity
Date
Time
Mixing sequence
pH
RPM
1
Time
1
Colour
2
2
3
4
3
4
Alkalinity
Jar
Chemicals
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
6
1 Alum (liquid)
Alum (dry)
2
3
4
5
6
Floc Characteristics
After flash mixing
After rapid mix
5 min slow mix
10 min slow mix
15 min slow mix
Floc Settling
5 mins
10 mins
20 mins
30 mins
Settled water quality
Turbidity
pH
Colour
Filterability
Comments
Worksheet 2 – Determine the process adjustment / coagulation processes
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