CENTRAL WATER
Standard Operating Procedure
1.
SOP 201
PREPARATION OF STANDARD JAR
TEST SOLUTIONS
Purpose
This standard operating procedure describes the process of preparing standard chemical solutions to be
used in performing a standard coagulant jar test. The following solutions can be produced following
this procedure:




2.
Alum 1%
Polyelectrolyte 0.01%
Lime 1%
Ferric Chloride 1%
Scope
This procedure is applicable to all, but not limited to Water Treatment Plants.
3.
Responsibility
3.1
Operations Manager – shall ensure that staff adheres to this procedure.
3.2
Coordinator Water Quality Team - shall ensure that:
•
•
3.3
Adequate chemical stocks are available; and
All Plant Equipment is available, in good working order and used in accordance with the
manufacturers instructions.
Water Quality Team Member – shall:
•
•
•
•
Prepare standard solutions
Ensure the accuracy of the final solutions;
Comply with all OHS requirements; and
Cleanup the work area ensuring all equipment is washed and ready for next use.
COAGULANT JAR TEST – SOP 202
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4.
Procedure
4.1
Preliminaries
4.1.1
Preparation


Rinse all containers and pipettes to be used to avoid possible impurities and
contamination.
Ensure there is enough room on the laboratory workbench.
Read and adhere to chemical MSDS’s.
Label and date each 250 – 1000 mL plastic bottle.
4.1.2
Dosing Solution Strengths

Coagulants – 1% (w/v) Alum or Ferric Chloride
Flocculation Aid – 0.01% (w/v) Polyelectrolyte
pH Correction – 1% (w/v) Soda Ash, Lime, Caustic or Sulphuric Acid
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
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4.1.3
4.2
All dosing solutions must be prepared from the actual chemicals used in the
treatment process of each individual plant. New solutions should be produced after
delivery of new treatment chemicals or no longer than one month after production.
Activity
4.2.1
Generic Procedure

Collect sample of concentrated chemical from chemical storages adhering to all OHS
requirements.
Pipette required volume of distilled water into bottle.
Seal bottle and agitate to ensure good mix.
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
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4.2.2
Preparation from Concentrated Chemical Solutions

For concentrated chemicals that are suppled as percent weight/weight (%w/w) solutions,
the dilution step required to make 1% w/v Jar Test solution must take into account the
specific gravity (Sg) of the concentrated chemical being diluted.
To calculate the volume of concentrated solution required to make a Jar Test dosing
solution the following formula is used.

4.2.2.1 Dosing Solution Alum
Vol of Stock Soln. (mL) = Dosing Soln.Strength (%w/v) x Final Volume (mL)
S.G x Stock Soln. strength (%w/v)
COAGULANT JAR TEST – SOP 202
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Example of how to calculate the Volume of stock soln. required to make 1000mL Alum:
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Stock soln. strength % = 46.5 (%w/v)
S.G. (Specific Grafity) = 1.3
Dosing soln. strength = 1 (%w/v)
Final Volume = 1000 mL
Vol of Stock Soln. (mL)
=
=
=
1 (% w/v) x 1000 mL
1.3 x 46.5 (%w/v)
1000
60.45
16.5 mL Stock Soln.
To make this up to 1000 mL of standard 1% solution it needs to be diluted with (1000 –
6.5) = 983.5 mL de-ionised water.
Measure 16.5 mL stock soln. into graduated cylinder and top up with de-ionised water to
make 1000 mL.
This formula can be used to calculate the volume of any concentrated solution to prepare
a dosing solution.
4.2.2.2 Dosing Solution Poly and Lime
Polymers are often prepared as various % w/v stock solutions, which are then diluted to
0.01% w/v dosing solutions. Lime and caustic are also often prepared as various % w/v
solutions. To calculate the volume of stock solution required to make a dosing solution
the following formula is used.
Vol of Stock Soln. (mL) = Dosing Soln.Strength (%w/v) x Final Volume (mL)
S.G x Stock Soln. strength (%w/v)
Example of how to calculate the volume of stock soln. required to make 250 mL poly:
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Stock soln. strength % = 0.25 (%w/v)
Dosing soln. strength = 0.01 (%w/v)
Final Volume = 250 mL
S.G = 1.0
Vol of Stock Soln. (mL)
=
=
=
COAGULANT JAR TEST – SOP 202
0.01 (% w/v) x 250 mL
1.0 x 0.25 (%w/v)
2.5
0.25
10 mL Stock Soln. into 240 mL de-ionised water
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Example of how to calculate the volume of stock soln. required to make 250 mL Soda
Ash:
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Stock soln. strength % =10 (%w/v)
Dosing soln. strength = 1.0 (%w/v)
Final Volume = 250 mL
S.G = 1.0
Vol of Stock Soln. (mL)
=
=
=
4.2.3
1.0 (% w/v) x 250 mL
1.0 x 10 (%w/v)
250
10
25 mL Stock Soln. into 225 mL de-ionised water
Preparation from Dry Chemicals
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The term “dry chemical” means the powdered chemical as supplied by the
manufacturer.
Both Alum and Ferric Chloride are prepared as a 1% weight/volume (w/v) solution
which is equivalent to 1 gram of dry chemical in 100mL of solution. Therefore, to
prepare a 1% w/v solution of alum, 1 gram of alum is added to de-ionised water to
make a final solution volume of 100mL.
When making coagulant, polymer or pH correction solutions from a dry chemical,
the following formula is used to determine the quantity of dry chemical.
Mass of dry chemical (g) = Dosing Soln.Strength (%w/v) x Final Volume (mL)
100
Example of how to calculate the Volume of stock soln. required to make 250mL Soda
Ash or Lime:


Dosing soln. strength = 1.0 (%w/v)
Final Volume = 250mL
Vol of Stock Soln.
=
=
=
4.3
1.0 (% w/v) x 250 mL
100
250
100
2.5 g Dry Chemical Stock into 250 mL de-ionised
water
Cleanup


Store prepared chemicals in an orderly place.
Wash all used laboratory equipment and put away.
COAGULANT JAR TEST – SOP 202
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5.0
Documentation
Nil
6.0
7.0
References
6.1
MSDS’s (Material Safety Data Sheets)
6.2
Chemical Supplier fact sheets
Definitions and Acronyms
Nil
COAGULANT JAR TEST – SOP 202
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