Jar Testing of Chemical Dosages

Prepared ByMichigan Department of Environmental Quality

Operator Training and Certification Unit

Jar Testing• Determination of most effective chemical

• Determination of most effective dosage

• Determination of optimum point of

application

• Evaluation of

polymers

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

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)

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)

Preparation of Stock Solutions

Solution DilutionSolution Dilution

45 % X 1.49 X V1 = 1 % X 1000 ml

C1 = 45 % (weighs 1.49 grams/ml)V1 = ? mlC2 = 1 % (weighs 1.00 grams/mlV2 = 1000 ml

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

= 14.91 ml1 % X 1000 ml 45 % X 1.49

V1 =

Jar Testing

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)

Preparation of Stock Solutions

Blank 5 mg/L 10 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.

1000 ml

1% = 10,000 mg/L

10,000 mg/L X ? ml = 5 mg/L X 1000 ml

? ml = 5 mg/L X 1000 ml 10,000 mg/L

? ml = 5 X 0.1 = 0.5 ml

10 X 0.1 = 1.0 ml15 X 0.1 = 1.5 ml20 X 0.1 = 2.0 ml25 X 0.1 = 2.5 ml

Jar Testing Calculations

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

Jar Testing

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

Procedure

Gang Stirrer

Addition of Chemicals

Rapid Mix

Slow Mix - Flocculate

Settle

Determine which dosage is best for meeting requirements

Chemical Handling Chemical Handling 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 8.34 lbs/gal X 25 mg/L

= 73 lbs/D FeCL3

Chemical Handling Chemical Handling

Given lbs/d of dry chemical to feed, need to calculate the gallons of solution to feed.

Specific Gravity = the number of times heavier or lighter the solution is than water

1 gallon of water weighs 8.34 lbsSpecific gravity of water = 1.000

Specific Gravity

If a solution has a Specific Gravity of 1.510,then this solution is 1.510 times heavier thanwater.

8.34 lbs/gal X 1.510 = 12.59 lbs/gal

A solution with a Specific Gravity of 0.750would weigh:

8.34 lbs/gal X 0.750 = 6.255 lbs/gal

Specific Gravity

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

Chemical Handling Chemical Handling

Strength of Concentrated Solutions are usually given as Percent by Weight

In 100 lbs of a 35 % solution there are 35 lbs of dry chemical

35 % = 35 lbs dry chem

100 lbs solution35 % = 35 per 100

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 1.43 = 11.93 lbs per gallon liquid

B. Determine the lbs of dry chemical in each gallon.

11.93 lbs X = 4.77 lbs dry chem/ gal40 lbs dry chem100 lbs solution

OR11.93 lbs X = 4.77 lbs dry chem/ gal 0.40

Chemical Handling Chemical Handling

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

ie) 150 lbs per day ferric chloride are to be fed. The solution to be used is 38% with a specific gravity of 1.413. Calculate the gallons of solution to feed each day.

8.34 lbs/gal X 1.413 = 11.78 lbs/gal

0.38 X 11.78 lbs/gal = 4.48 lbs dry chem/gal

150 lbs/d dry chem needed 4.48 lbs dry chem/gal = 33.5 gal/day

Chemical Handling Chemical Handling

Chemical Handling Chemical Handling

Pumping Rate Calculations

Given gallons per day of chemical needed, calculate gallons per minute

GalDay

X 1 Day24 Hrs

X 1 Hr60 Min

= GalMin

mlsSec

X 1 Gal 3785 mls

X 60 Sec Min

= GalMin

Calibration of Chemical Feed Pump

1. Set pump at known setting2. 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.

Chemical Feed Summary1. 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:

galDay

X 1 Day24 Hrs

X 1 Hr60 Min

= GalMin

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

Chemical Handling Calculations Example Problem #1

1. Calculate the pounds per day of FeCl3 that must be added to the wastewater flow.

Jar Test Results 23 mg/L FeCl3 Dosage NeededWastewater Flow 300,000 gallons per day

Ferric Chloride SolutionSpecific Gravity 1.500Concentration 45 %

Work Calculations on Separate PaperAnswers Given on Next Slides

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 ?

Chemical Handling Calculations Example Problem #1

1. Calculate the pounds per day of FeCl3 that must

be added to the wastewater flow.

Jar Test Results 23 mg/L FeCl3 Dosage NeededWastewater Flow 300,000 gallons per day

Ferric Chloride SolutionSpecific Gravity 1.500Concentration 45 %

lbs/d = 23 mg/L X 8.34 lbs/gal X 0.30 MGD

= 57.55 lbs/d

3. Calculate the pounds of dry FeCl3 per gallon of the solution.

12.51 lbs/gal X 0.45 = 5.63 lbs dry/gallon

8.34 lbs/gal X 1.500 = 12.51 lbs/gal

2. Calculate the weight in pounds of a gallon of the FeCl3 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 ?

57.55 lbs/day needed5.63 lbs dry/gallon

= 10.2 gallons/day

10.2 gal Day

X 1 Day24 Hrs

X 1 Hr60 Min

= 0.0071 Gal Min

0.0071 gal min

X 3785 mls gal

26.12 ml/min=

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.

Chemical Handling Calculations Example Problem #2

Work Calculations on Separate PaperAnswers Given on Next Slide

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 = 31.28 lbs/d

8.34 lbs/gal X 1.33 X 0.49 = 5.44 lbs dry/gal

31.28 lbs dry needed/day

5.44 lbs dry/gallon= 5.75 gal/day

15.11 ml/min5.75 galday

X 3785 mls gal

1 day

1440 min X =

Chemical Handling Calculations Example Problem #2

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 1.430. Calculate the chemical dosage in mg/L.

Chemical Handling Calculations Example Problem #3

Work Calculations on Separate PaperAnswers Given on Next Slide

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 1.430. Calculate the chemical dosage in mg/L.

8.34 lbs/gal X 1.430 X 0.40 = 4.77 lbs dry/gal

120 gal X 4.77 lbs dry/gal = 572.5 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

= 27.5 mg/L

Chemical Handling Calculations Example Problem #3

Jar Testing of Chemical Dosages

Prepared ByMichigan Department of Environmental Quality

Operator Training and Certification Unit