1. Jar Testing of Chemical Dosages
Prepared By
Michigan Department of Environmental Quality
Operator Training and Certification Unit

2. Jar Testing Determination of most effective chemical
Determination of most effective dosage
Determination of optimum point of application
Evaluation of
polymers

3. Jar Testing Equipment Needed: Gang Stirrer
6 Graduated Beakers, 1500 ml
2 Graduated Pipets, 10 ml
1 Graduated Cylinder, 1000 ml
Scale for weighing chemicals
Analytical Equipment

4. Jar Testing Preparation of Stock Solutions
For alum, lime, other dry materials:
Use a 1 % solution. Dissolve 10 grams into 1000 ml distilled water.
(1 ml = 10 mg/l in 1000 ml)

5. Preparation of Stock Solutions
For Ferric Chloride, other liquid materials:
Use a 1 % solution. Obtain % solution and specific gravity from supplier.
Dilute appropriate volume up to 1000 ml to make a 1 % (10,000 mg/L) solution.
(1ml=10 mg/l in 1000 ml)

6. Solution Dilution Have 45 % Ferric Chloride Solution
(Specific Gravity 1.49)
Need 1000 mls of a 1 % (10,000 mg/L) Sol.
C1 X V1 = C2 X V2
C1 = 45 % (weighs 1.49 grams/ml)
V1 = ? ml
C2 = 1 % (weighs 1.00 grams/ml
V2 = 1000 ml
45 % X X V1 = 1 % X 1000 ml
1 % X 1000 ml
45 % X 1.49
V1 =
= ml

7. Jar Testing Preparation of Stock Solutions For Dry or Liquid Polymers:
Use a 0.01 % (100 mg/L) solution. Weigh
0.1 gram and dissolve in 1000 ml distilled water.
(1 ml = 0.1 mg/l in 1000 ml)

8. Jar Testing Calculations
1000 ml
Blank mg/L mg/L 15 mg/L 20 mg/L 25 mg/L
Calculate the volume of a 1 % Ferric Chloride solution that would be added to get the dosage required.
1% = 10,000 mg/L
10,000 mg/L X ? ml = 5 mg/L X ml
10 X 0.1 = 1.0 ml
15 X 0.1 = 1.5 ml
20 X 0.1 = 2.0 ml
25 X 0.1 = 2.5 ml
? ml = 5 mg/L X ml
10,000 mg/L
? ml = 5 X = 0.5 ml

9. Jar Testing Calculations
A jar test indicates that the required amount of phosphorus removal can be achieved using a dosage of 3 ml of a 1% ferric chloride solution in a liter of wastewater. What is the dosage in mg/L?
C1 X V1 = C2 X V2
10,000 mg/L X 3 ml = ? mg/L X 1000 ml
10,000 mg/L X 3 ml
1000 ml
= 30 mg/L

10. Jar Testing
Procedure
Using the 1000 ml graduated cylinder, add 1000 ml wastewater to each beaker.
Using the graduated pipets, dose each beaker with the desired concentration of metal salt or polymer, increasing concentration from left to right.
Operate stirrer to simulate plant process.
Determine best dosage level by analysis of supernatant

11. Gang Stirrer Addition of Chemicals Rapid Mix Slow Mix - Flocculate
Settle

12. Determine which dosage is best for meeting requirements

13. Chemical Handling lbs/day = MGD X 8.34 lbs/gal X mg/L
After jar testing has been used to determine best chemical dosage in mg/L, pounds of chemical needed per day into a given flow or volume can be calculated.
lbs/day = MGD X 8.34 lbs/gal X mg/L
ie) A dosage of 25 mg/L Ferric Chloride is needed. The flow to be treated is 350,000 gallons per day. How many lbs of Ferric Chloride will have to be fed each day?
lbs/D = 0.35 MGD X lbs/gal X 25 mg/L
= 73 lbs/D FeCL3

14. Chemical Handling Specific Gravity
Given lbs/d of dry chemical to feed, need to
calculate the gallons of solution to feed.
Specific Gravity
Specific Gravity = the number of times
heavier or lighter the solution is than water
1 gallon of water weighs 8.34 lbs
Specific gravity of water = 1.000

15. Specific Gravity If a solution has a Specific Gravity of 1.510,
then this solution is times heavier than
water.
8.34 lbs/gal X = lbs/gal
A solution with a Specific Gravity of 0.750
would weigh:
8.34 lbs/gal X = lbs/gal

16. Obtain S.G. from Supplier or by Using a Hydrometer

17. Chemical Handling 35 lbs dry chem 35 % = 35 per 100 35 % =
Strength of Concentrated Solutions are
usually given as Percent by Weight
35 % =
35 lbs dry chem
100 lbs solution
35 % =
35 per 100
In 100 lbs of a 35 % solution there are 35 lbs of dry chemical

18. If the weight of a gallon of solution is known, the weight of dry chemical in each gallon of the solution can be calculated:
A 40% solution has a specific gravity of 1.43
A. Determine the weight of a gallon of the solution.
8.34 lbs/gallon X = lbs per gallon liquid
B. Determine the lbs of dry chemical in each gallon.
11.93 lbs X
= lbs dry chem/ gal
40 lbs dry chem
100 lbs solution OR
11.93 lbs X
= lbs dry chem/ gal
0.40

19. Chemical Handling lbs/day dry chem needed lbs dry chem / gal
Feed Rates
If the lbs per day of chemical to be fed is known, and we know the pounds of dry chemical in each gallon of the solution, the gallons per day of solution to be fed can be calculated.
lbs/day dry chem needed
lbs dry chem / gal
= gal/day soln to be fed

20. Chemical Handling
ie) 150 lbs per day ferric chloride are to be fed. The solution to be used is 38% with a specific gravity of Calculate the gallons of solution to feed each day.
8.34 lbs/gal X = lbs/gal
0.38 X lbs/gal = lbs dry chem/gal
150 lbs/d dry chem needed
4.48 lbs dry chem/gal
= 33.5 gal/day

21. Chemical Handling Pumping Rate Calculations
Given gallons per day of chemical needed, calculate gallons per minute
Gal
Day X
1 Day
24 Hrs
1 Hr
60 Min =
Min

22. Calibration of Chemical Feed Pump
1. Set pump at known setting
2. Start pump and collect at the application point a measured amount in a known period of time.
3. Repeat for various settings.
4. Convert to needed units.
mls
Sec X
1 Gal
3785 mls
60 Sec
Min =
Gal

23. Chemical Feed Summary 1. Determine lbs/day of dry chemical needed.
2. Determine the weight (lbs/gal) of the soln.
3. Determine weight of dry chem in each gallon.
4. Determine gallons per day to be fed.
5. To Determine pumping rate in gallons/minute:
mg/L X MGD X 8.34 lbs/gal = lbs/d dry chem
8.34 lbs/gal X Sp.Gr. = lbs/gal (liquid weight)
lbs/gal (liquid wt) X % soln = lbs dry/gallon
Lbs dry needed per day = gal/day to be fed
lbs dry/gallon
gal
Day X
1 Day
24 Hrs
1 Hr
60 Min =
Gal
Min

24. Chemical Handling Calculations Example Problem #1
Jar Test Results 23 mg/L FeCl3 Dosage Needed
Wastewater Flow 300,000 gallons per day
Ferric Chloride Solution
Specific Gravity 1.500
Concentration 45 %
Work Calculations on Separate Paper
Answers Given on Next Slides
1. Calculate the pounds per day of FeCl3 that must be added to the wastewater flow.
2. Calculate the weight in pounds of a gallon of the FeCl3 solution.
3. Calculate the pounds of dry FeCl3 per gallon of the solution.
4. Calculate the number of gallons of the FeCl3 solution that must be fed per day.
5. How many gallons per minute must the chemical feed pump be set to deliver ?

25. Chemical Handling Calculations Example Problem #1
Jar Test Results 23 mg/L FeCl3 Dosage Needed
Wastewater Flow 300,000 gallons per day
Ferric Chloride Solution
Specific Gravity 1.500
Concentration 45 %
1. Calculate the pounds per day of FeCl3 that must be added to the wastewater flow.
lbs/d = 23 mg/L X lbs/gal X MGD
= lbs/d

26. 2. Calculate the weight in pounds of a gallon of the FeCl3 solution.
8.34 lbs/gal X = lbs/gal
3. Calculate the pounds of dry FeCl3 per gallon of the solution.
12.51 lbs/gal X = lbs dry/gallon

27. 4. Calculate the number of gallons of the FeCl3 solution that must be fed per day.
57.55 lbs/day needed
5.63 lbs dry/gallon
= gallons/day
5. How many gallons per minute must the chemical feed pump be set to deliver ?
10.2 gal
Day X
1 Day
24 Hrs
1 Hr
60 Min =
Gal
Min
gal
min X
3785 mls
gal
26.12 ml/min =

28. Chemical Handling Calculations Example Problem #2
Calculate the number of milliliters per minute that must be fed of a 49 % Aluminum Sulfate solution with a specific gravity of 1.33 to dose a flow of 150,000 gallons per day at 25 mg/L.
Work Calculations on Separate Paper
Answers Given on Next Slide

29. Chemical Handling Calculations Example Problem #2
Calculate the number of milliliters per minute that must be fed of a 49 % Aluminum Sulfate solution with a specific gravity of 1.33 to dose a flow of 150,000 gallons per day at 25 mg/L.
25 mg/L X 0.15 MGD X 8.34 lbs/gal = lbs/d
8.34 lbs/gal X X = lbs dry/gal
31.28 lbs dry needed/day
5.44 lbs dry/gallon
= gal/day
5.75 gal
day X
3785 mls
gal
1 day
1440 min =
15.11 ml/min

30. Chemical Handling Calculations Example Problem #3
120 gallons/day of a ferric chloride solution was fed into a flow of 2.5 MGD. The ferric chloride solution had a concentration of 40 % and a specific gravity of Calculate the chemical dosage in mg/L.
Work Calculations on Separate Paper
Answers Given on Next Slide

31. Chemical Handling Calculations Example Problem #3
120 gallons/day of a ferric chloride solution was fed into a flow of 2.5 MGD. The ferric chloride solution had a concentration of 40 % and a specific gravity of Calculate the chemical dosage in mg/L.
8.34 lbs/gal X X = lbs dry/gal
120 gal X lbs dry/gal = lbs dry/day
572 lbs/day = 2.5 MGD X 8.34 lbs/gal X mg/L
572 lbs/day
2.5 MGD X 8.34 lbs/gal
= mg/L

32. Jar Testing of Chemical Dosages
Prepared By
Michigan Department of Environmental Quality
Operator Training and Certification Unit