A Simplified Jar Test Procedure Phipps&Bird

A SIMPLIFIED JAR TEST PROCEDURE Acknowledgement The procedures outlined in this publication appear courtesy of the West Virginia Rural Water Association. A special note of thanks to Larry Rader, former Program Specialist of the WVRWA, for his enthusiasm in promoting the benefits of jar testing.

FORMULAS AND CONVERSIONS BASIC LAB EQUIPMENT FOR SMALL WATER TREATMENT PLANTS LABORATORY FACILITIES THE JAR TEST •

PROCEDURE

•

INFORMATION

JAR TESTING FOR POTASSIUM PERMANGANATE DEMAND CORROSION CONTROL WORKSHEET

1519 Summit Avenue, Richmond, Virginia 23230 Phone: 804-254-2737 or toll free: 800-955-7621 (USA). Fax: 804-254-2955 Send E-mail to Phipps & Bird

FORMULAS AND CONVERSIONS PERCENT SOLUTION TABLE %*

lb/gal

oz/gal

1

0.084

1.3

2

0.170

2.7

3

0.258

4.1

4

0.348

5.6

5

0.440

7.0

6

0.533

8.5

7

0.629

10.1

8

0.726

11.6

9

0.825

13.2

10

0.929

14.9

* Approximate % by weight

Feed Rate Formulas

CONVERSIONS Ounces (fluid) x 29.57

= mL

Ounces (dry) x 28.35

= Grams

Cubic Ft. x 7.5

= gallons

Gal x 8.34

= Lbs

Gal x 3785

= mL

Gal/Hr x 63

= mL/MIN

Grains/Gal x 17.1

= PPM

Grams x 15.43

= Grains

MGD x 694

= GPM

10,000 PPM

= 1%

Pounds x 453

= Grams

PPM x 8.33

= Lb/Mil. Gal

Quarts x 946

= mL

Cubic Ft. x 62.4

= Pounds

Pounds x 7000

= Grains

Gal x 3.785

= Liters

1 Mile

= 5280 ft

2.31 ft. of water 

= 1 psi

0.433 psi

= 1 ft/water 

In the following calculations: pi = 3.14, L = Length, W = Width D = Diameter, H = Height Area = A(sq ft.): Rectangle: V= L x W

= lb/hr  Circle: V= Volume = V( cu. ft.): Rectangular Tanks: V= L x W x H = gal/hr  Circular Tanks: V=

= PPM In Pipes: V= = PPM GPM = GPM of plant * 6 min collection for dry feeder 

Divide pipe diameters by 12 to convert from inches to feet. Example: 8 inch pipe divided by 12 equals 0.66 feet.

BASIC LAB EQUIPMENT FOR SMALL WATER TREATMENT PLANTS Equipment applicable to both surface and ground water plants.

1 ..........

Copy of latest edition of "Standard Methods for the Examination of Water and Waste Water", American Public Health Association, Inc., 1015 Eighteenth St., N.W., Washington, DC 20036.

1 ..........

Colorimeter or Spectrophotometer capable of performing various tests to determine the chemistry of both raw and finished water. Tests could include: Chlorine(free and total), Iron, Manganese(high and low range), Aluminum (if you use Alum), Nitrates (if you are in a farming area), Phosphorous (if you are using a orthophospate for corrosion control or dirty water complaints), and Flouride (SPADNS Method). A good colorimeter or spectrophotometer should be capable of performing all of the tests listed in addition to several other parameters which could be applicable to your plant. Contact your state Department of Health to determine the parameters required at your plant. Hach and LaMotte, as well as other suppliers, offer good quality equipment as well as technical expertise.

 As required... Reagent sets for tests to be performed with colorimeter or spectrophotometer, EPA approved if possible.

1 ..........

Bench type pH Meter, preferable with temperature compensation (Hach, LaMotte, Fisher, Orion and others). The pH Meter should include a stand for the probe and an electric stirrer. Also, a supply of pH 4, pH 7 and pH 10 buffer solutions should be on hand for calibrating the meter.

1 ..........

Thermometer, -10 to 110 degrees °C.

 As required... Alkalinity, Hardness and CO 2 tests are usually performed using one of two titration methods (digital titrator and buret). The digital titrator method (Hach) requires a digital titrator and the appropriate reagent set. The buret method may be purchased as a complete outfit, (LaMotte and others), or the components purchased separately. When purchased separately the following items are required: Buret support with large white porcelain base and a buret holder for assembling and steadying automatic burets. Each separate test will require one automatic buret, with stopcock, 50 or 100 mL, complete with rubber bulb and reservoir and the appropriate reagents for each test.

1 ..........

Balance, general laboratory, triple beam, in grams (Ohaus Dial-O-Gram, Ohaus Cent-O-Gram or others)

1 ..........

Technical weights, set, metric, class C, 1 gram to 1000 gram, for balance calibration.

1 ..........

Stopwatch

6 ..........

Measuring pipets, 10.0 mL capacity, 0.1 mL subdivisions.

6 ..........

Measuring pipets, 1.0 mL capacity, 0.01 mL subdivisions.

2 ..........

Pipet fillers.

2 ..........

Graduated cylinders, 100 mL Capacity, 1.00 mL subdivisions.

1 ..........

Graduated cylinder, 500 mL Capacity, 5.00 mL subdivisions.

1 ..........

Graduated cylinder, 1000mL Capacity, 10.00 mL subdivisions.

4 ..........

Erlenmeyer flasks, 250 ml, wide mouth.

4 ..........

Casserole, porcelain, 210 mL.

6 ..........

Glass stirring rods, 3 mm diameter 

The following items are required in plants treating surface water, or in plants using ground water which has been determined to be under the influence of surface water. These items are in addition to the equipment already listed.

1 ..........

Turbidimeter (Hach, Tumer, LaMotte, HF, etc.)

 As required... Primary turbidity standards. Turbidimeters must be standardized using a standard approved by your state Department of Health.

1 ..........

Six position stirring apparatus for "Jar Tests" with variable speed control and light base (Phipps & Bird).

1 ..........

Griffin beakers, 1000 mL (Phipps & Bird) or 2 Square 2000 mL laboratory jars (B-Ker  , Phipps & Bird)

LABORATORY FACILITIES  Adequate laboratory space must be made available. As a guideline, there should be approximately 150 to 200 square feet per person, regardless of tests. There should be approximately 15 linear feet of usable bench space including a sink with hot and cold water taps. Raw and post-settling water taps should be provided in the lab area for quality control monitoring. Sufficient electrical outlets must be provided for operating the lab equipment. The lab must be well lighted and in a room separate from the rest of the plant.  All glassware purchased for lab use should be Pyrex or Kimex type glass. This type of glass is more resistant to damage by heat, chemicals and abuse than is regular soft glass. All volumetric glassware should be marked "Class A", denoting that it meets federal specifications for volumetric glassware and need not be calibrated before use. This list includes only the MINIMUM equipment needed to properly operate a water treatment plant. Every plant is different and yours may need additional items. However, before purchasing large quantities of unknown lab equipment (as in a new plant) contact your state Department of Health or Rural Water Association to determine whether or not you are getting what you need, nothing more, nothing less. Because of the difference in suppliers, specific reagents are not listed. The manufacturer of your lab equipment will provide you with the reagents compatible with their products.

THE JAR TEST Jar testing, to determine the proper coagulant dosage, continues to be one of the most effective tools available to surface water plant operators. Finished water quality, cost of production, length of filter runs and overall filter life, all depend on the proper application of chemicals to the raw water entering the treatment plant. Before you start The jar test, as with any coagulant test, will only provide accurate results when properly performed. Because the jar test is intended to simulate conditions in your plant, developing the proper procedure is very important. Take time to observe what happens to the raw water in your plant after the chemicals have been added, then simulate this during the jar test. THE RPM OF THE STIRRER AND THE MINUTES TO COMPLETE THE TEST DEPEND ON CONDITIONS IN YOUR PLANT.  If, for instance, your plant does not have a static or flash mixer, starting the test at high rpm would provide misleading results. This rule applies to flocculator speed, length of settling time and floc developement. Again, operate the jar test to simulate conditions in  YOUR plant. Equipment 1 ..........Phipps & Bird Six-Paddle Stirrer with Illuminated Base. 2 6 ..........Graduated beakers, 1000 mL or B-Ker   2000 mL square jars (Phipps & Bird). 2 ..........10 mL graduated pipets. 1 ..........1000 mL graduated cylinders. 1 ..........Scale for weighing coagulants. Lab apparatus to measure alkalinity, pH and turbidity. Stock Solutions Stock solutions are prepared by dissolving 10.0 grams of alum, soda ash, lime, etc. into 1000 mL distilled water. Each 1.0 mL of this stock solution will equal 10 mg\L when added to 1000 mL of water to be tested. Because dry polymers tend to be fed at much lower concentrations, a stock solution should contain 1.0 gram polymer to 1000 mL distilled water. Each mL of this stock solution will equal 1.0 mg\L when added to 1000mL of water to be tested. You might want to use a 1.0 mL graduated pipet with 0.1 mL subdivisions when jar testing polymers. Liquid polymers should be added in the concentration recommended by the manufacturers. Information First check the alkalinity and pH of the water to be tested. Water containing an alkalinity of at least 25 mg\L and pH of around 7.0 will coagulate without the addition of lime, soda ash, etc. (Adding chemicals for pH adjustments, in pre-treatment, can be a major waste if they are not needed). Keep in mind that this will lower pH. Color, as opposed to turbidity, is almost always removed best at depressed pH values. The additon of acid or larger doses of alum may be needed to accomplish color removal. Some color is removed at pH 7.0 but higher raw water colors may require a full unit lower. If, on the other hand, you are removing manganese in the floc process, the higher you can elevate the pH and still form floc, the better the manganese removal.

PROCEDURE Procedure 2 Using the 1000 mL graduated cylinder, add 1000 mL (or 2000 mL if using the B-Ker   2-liter square  jar) of the raw water to be coagulated to each of the jar test beakers. Using the prepared alum (or other coagulant) stock solution dose each beaker with increasing amounts, using the following 2 schedule as an example (Double the dosage when using B-Ker   2-liter square jars). If necessary, add lime or soda ash stock solution to maintain correct alkalinity. Jar #

mL Alum Stock

mL Lime\ mg\L Soda Ash  Alum

mg\L Lime Soda Ash

1

0.5

0

5.0

0

2

1.0

0

10.0

0

3

1.5

0

15.0

0

4

2.0

0.5

20.0

5.0

5

2.5

1.0

25.0

10.0

6

3.0

1.5

30.0

15.0

The above schedule is meant as an example. You should through trial and error establish your own sampling schedule that takes into account your own plant's operation and quality of the water at the intake. IMPORTANT: ALWAYS KEEP ACCURATE NOTES PERTAINING TO DOSING WHILE PERFORMING JAR TESTS. Example: Your plant has a static mixer after the chemicals are injected, followed by 30 minutes in a flocculator, then 2 hours settling time before the filter.  After dosing each beaker, operate the stirrer at high rpm for a pproximately 1 minute. This simulates the static mixer. Then, slow to the rpm which matches the turbulence created in your flocculators and allow to stir for 30 minutes while observing the floc formation. At the end of the 30 minutes turn the stirrer off and allow to settle. Because there are 2 hours of settling time in this plant, at the end of 1 hour most of the settling will be complete.  A coagulant underfeed will cause the sample to appear cloudy, with little or no floc and almost no settling. A coagulant overfeed will form dense floc, however, it will appear fragile and fluffy; when the stirrer is turned off, it will not settle well. Floc formed by an overfeed is false floc which is very light and will carry to the filter. This is one of the most common treatment problems. A good floc will appear heavy and tight, not too dense, with spaces of bright, clear water between the particles and will begin to settle as soon as the stirrer is turned off.

INFORMATION More Information  A tap installed in the raw water immediately after the chemicals are injected is indispensable. A sample taken from this tap can be placed on the stirrer to quickly determine the effectiveness of the dosage being used. In order to add chemicals accurately, feeders must be calibrated. If you are experiencing trouble when the raw water is clear and cold, and if your flocculators are

adjustable, speed them up. This will improve the collision rate during cold water conditions.  A good formula to use for chemical application: PPM x GPM / 2,000 = Ibs. per hour PPM you determine by the jar test. GPM is the gpm at which your plant operates. 2,000 is a given number. If you use alum as a coagulant you should test the finished water for aluminum content. This is a good indicator of how well the coagulation flocculation process is working. An elevated aluminum level could indicate alum overfeed. Placing a black background behind the jar test will give you a better view of the floc process. When purchasing jar test apparatus there are two very important features to look for: Adjustable stirring rate and an illuminated base. Without adjustable speeds you will be unable to simulate conditions in your plant. The light base provides a full and clear view of all the beakers simultaneously. Light bases using fluorescent bulbs will not change the temperature of the sample significantly. The jar test is intended to simulate the coagulation flocculation process in your plant. Designing a  jar test procedure to match conditions in your plant takes a little thought and practice on the operator's part. However, when you have developed the proper routine and then properly applied the results, you will be producing the best water possible at the lowest cost.

JAR TESTING FOR POTASSIUM PERMANGANATE DEMAND Stock Solutions (Strong Stock Solution) 5 grams potassium permanganate dissolved in 500 mL distilled water. (Test Stock Solution) 1 mL strong stock solution thoroughly mixed in 100 mL distilled water. Each 10 mL of the test stock solution added to a 1000 mL sample equals 1 ppm. If you have a six position stirrer: Using a graduated cylinder, measure 1000 ml . of the sample to be tested into each of the six beakers. Dose each beaker to simulate plant practices in pre-treatment, pH adjustment, coagulant, etc. Do not add carbon or chlorine. Using a graduated pipet, dose each beaker with the test stock solution in the following manner. Jar #

KMnO4 mL

KMnO4 ppm

Color 

1

1.0

0.10

no pink

2

1.5

0.15

no pink

3

2.0

0.20

no pink

4

2.5

0.25

no pink

5

3.0

0.30

pink

6

3.5

0.35

pink

Stir the beakers to simulate the turbulence where the KMnO 4 is to be added and observe the color change.  As the iron and manganese begin to oxidize, the sample will turn varying shades of brown, indicating the presence of oxidized iron and or manganese. Samples which retain a brown or yellow color indicate that the oxidation process is incomplete and will require a higher dosage of KMnO 4. The end point has been reached when a pink color is observed and remains for at least 10 minutes. In the preceding table a pink color first developed in beaker #5 which had been dosed with 3 mL/0.3 ppm. If the first jar test does not produce the correct color change, continue with increased dosages. When applying potassium permanganate to raw water, care must be taken not to bring pink water to the filter unless you have "green sand". Also, permanganate generally reacts more quickly at pH levels above 7.0.  A quick way to check the success of a KMnO 4 application is by adding 5 mL of the test stock solution to 1000 mL finished water. If the sample turns brown there is iron or manganese remaining in the finished water. If the sample remains pink, oxidation is complete. With proper application, potassium permanganate is an extremely useful chemical treatment. As well as being a strong oxidizer for iron and manganese, KMnO 4 used as a disinfectant in pre-treatment could help control the formation of trihalomethanes by allowing chlorine to be added later in the treatment process or after filtration. Its usefulness also extends to algae control as well as many taste odor problems.

CORROSION CONTROL By pH - Alkalanity Relationship This graph may be used for estimating the corrosiveness of water. If the total alkalinity and pH values intersect at a point on the graph below the bottom line, the water is corrosive. Raise the alkalinity and pH of the finished water by adding lime or soda ash until the point of intersection falls above the center curve. If the point of intersection falls above the top curve, overtreatment is indicated and undesirable calcium carbonate deposits may be expected.

One of the best tests for determining the corrosivity of water is the Langelier Saturation Index (Ll). The Ll requires the following tests: Calcium hardness, total alkalinity, pH, total d issolved solids (TDS), and water temperature in centigrade. Once the tests have been performed they are assigned a value from the following tables. Notice that hardness and alkalinity (C and D) both use the same table.

Water Temp (°C) A

TDS mg/L B

0 ............... 2.60 04 ............... 2.50 08 ............... 2.40 12 ............... 2.30 16 ............... 2.20 20 ............... 2.10 25 ............... 2.00 30 ............... 1.90 40 ............... 1.70 50 ............... 1.55 60 ............... 1.40 70 ............... 1.25 80 ............... 1.15

0 ............... 9.70 100 ............... 9.77 200 ............... 9.83 400 ............... 9.86 600 ............... 9.89 1000 ............... 9.90

Calcium Hardness and Total Alkalinity mg/LC/D

10 ............... 1.00 20 ............... 1.30 30 ............... 1.48 40 ............... 1.60 50 ............... 1.70 60 ............... 1.78 70 ............... 1.84 80 ............... 1.90 100 ............... 2.00 200 ............... 2.30 300 ............... 2.48 400 ............... 2.60 500 ............... 2.70 600 ............... 2.78 700 ............... 2.84 800 ............... 2.90 900 ............... 2.95 1000 ............... 3.00  After each test has been run and a value assigned, the following formula is used. 1. pHs = A + B - C - D then 2. LI = pH actual - pHs

Corrosive Characteristics

Langelier Index

Highly aggressive ....................................................... < -2.0 Moderately aggressive ............................................... -2.0 to 0.0

 Nonaggressive ........................................................... >0.0

WORKSHEET DATE and TIME ........................................................................................... OPERATOR .................................................................................................

TEST RESULT

(A) Temp. in °C ...........................................

VALUE from TABLES

(B) TDS in mg/L .......................................... (C) Calcium Hardness in mg/L ...................

*

(D) Alkalinity in mg/L ...................................

* Do not assign a value to pH, use the actual number.

Calculation using numbers from the right hand value column

+ -

(A) (B) (C)

.......................... .......................... ..........................

-

(D)

.......................... ..........................

Equals pHs Then:

-

(E)

 Actual pH.........

pHs

.......................... ..........................

Equals LI

_____________ + _____________ - _____________ = _____________ - _____________ = _____________ _____________ - _____________ = _____________

* Corrosivity of Sample

< -2.0

........................

Highly

-2.0 to 0.0

........................

Moderately

0.0

........................

Non

G- CURVES Source: Water and Air Research, Inc.

Velocity Gradient vs. Agitator Speed for a 2-liter Square 2 Beaker (B-KER ), Using a Phipps & Bird Stirrer. Water samples are at various temperatures (C°).