Jar Test Overview Calibration

Jar Test Overview Jar Test Overview & &

CalibrationCalibration

Bob JollyBob JollyRelief Control Center Operator, DMWWRelief Control Center Operator, DMWW

Barb DuffBarb DuffChemist, DMWWChemist, DMWW

What is jar testingWhat is jar testing

• Common lab procedureCommon lab procedure• Determine optimum operating conditions for your Determine optimum operating conditions for your

plantplant• Allows for adjustments inAllows for adjustments in

• pHpH• Coagulant & polymer dose, location, brandCoagulant & polymer dose, location, brand• Mixing speedMixing speed

• Simulates rapid mix, coagulation, flocculation and Simulates rapid mix, coagulation, flocculation and settling processsettling process

• Predicts functioning of full scale plantPredicts functioning of full scale plant• Times and concentrations in this presentation are Times and concentrations in this presentation are

specific to DMWW treatment plantsspecific to DMWW treatment plants

Jar Testing ApparatusJar Testing Apparatus 6 paddles stir the contents of six 2 liter jars 6 paddles stir the contents of six 2 liter jars

at a uniform speedat a uniform speed One jar acts as a controlOne jar acts as a control Operating conditions varied in the Operating conditions varied in the

remaining 5 containersremaining 5 containers RPM gauge controls mixing speed in all RPM gauge controls mixing speed in all

jarsjars

Gang style Gang style mixermixer

Advantage of 2L Square JarsAdvantage of 2L Square Jars

Better mixing Better mixing Mixing curve availableMixing curve available Better insulating propertiesBetter insulating properties More water for testing – 2 litersMore water for testing – 2 liters Standard Sampling location (10cm) used Standard Sampling location (10cm) used

to set settling velocityto set settling velocity

WP Supervisor, Fleur Plant, asked:WP Supervisor, Fleur Plant, asked:

Hypothesis:Hypothesis: is 5mg/L ferric chloride, the is 5mg/L ferric chloride, the current plant dosage, the correct chemical dose current plant dosage, the correct chemical dose for optimum turbidity and cost efficiencyfor optimum turbidity and cost efficiency

VariableVariable = Ferric Chloride = Ferric Chloride

Goal – HypothesisGoal – Hypothesis

Basic Jar Test ProcedureBasic Jar Test Procedure

Before We Begin:Before We Begin:

Leg workLeg work

Obtain plant designObtain plant design

Plant engineerPlant engineer PBT facilitatorPBT facilitator

Obtain Plant parameters:Obtain Plant parameters: Plant Dose:Plant Dose:

• Ferric chloride Ferric chloride • Alum Alum • CarbonCarbon• Lime Lime

Obtain Plant Source Water Obtain Plant Source Water Quality:Quality:

pH:pH: T Alk:T Alk: T Hard:T Hard: Turbidity:Turbidity:

Source Water:Source Water: WellsWells ReservoirReservoir LakeLake RiversRivers

Prepare Chemicals And Stock Prepare Chemicals And Stock SolutionsSolutions

Decide on chemical Decide on chemical

dose and volumesdose and volumes

Workable Workable

concentrationconcentration

Collect Water Sample And Fill JarsCollect Water Sample And Fill JarsRaw WaterRaw Water

Start Mixer Start Mixer Dose Coagulants SimultaneouslyDose Coagulants Simultaneously

Mix 2 min @ 20 rpmMix 2 min @ 20 rpm

Add chemicals in Add chemicals in same sequence same sequence as the plantas the plant

RAPID MIX – CoagulationRAPID MIX – Coagulation3 Minutes @ 238 rpm3 Minutes @ 238 rpm

Ferric Chloride = Variable Alum = Constant

0mg/L 2mg/L 4mg/L 5mg/L 8mg/L 10mg/L

FERRIC DOSE

Adjust Mixer Speed Adjust Mixer Speed To Simulate Flocculation 31rpm To Simulate Flocculation 31rpm

Add Chemicals Add Chemicals

Lime AdditionLime AdditionpH 10.8pH 10.8

FlocculationFlocculation

4 min @ 31 rpm4 min @ 31 rpm

thenthen

28 min @ 13 rpm28 min @ 13 rpm

Stop Mixer And Allow To Settle Stop Mixer And Allow To Settle 15 minutes; 0 rpm15 minutes; 0 rpm

Sample Jars And AnalyzeSample Jars And Analyze

Record Visual Observations at Record Visual Observations at All StagesAll Stages

Beginning water quality: no turbidityBeginning water quality: no turbidity Following alum and ferric addition: pin floc in Following alum and ferric addition: pin floc in

jars 2 thru 6jars 2 thru 6 Following lime addition: increase in floc size Following lime addition: increase in floc size

and density with increased ferric additionand density with increased ferric addition During settling: Deep settled floc in jars 4,5,6During settling: Deep settled floc in jars 4,5,6 Jar 1 showed minimal pin floc formationJar 1 showed minimal pin floc formation

Record Results on WorksheetRecord Results on Worksheet

Jar #Jar # Lime pHLime pH Ferric Ferric ppmppm

Alum Alum ppmppm

NTU @ NTU @ 15 min.15 min.

11 10.810.8 00 55 2020

22 10.810.8 22 55 14.714.7

33 10.810.8 44 55 8.58.5

44 10.810.8 55 55 6.46.4

55 10.810.8 88 55 4.74.7

66 10.810.8 1010 55 3.03.0

Interpret ResultsInterpret ResultsTurbidity vs Ferric Dosage

0

5

10

15

20

0 2 4 6 8 10 12

Ferric Dosage

NT

U Plant Dose 5 mg/L

•Optimized for turbidity reduction and costOptimized for turbidity reduction and cost

Draw ConclusionsDraw Conclusions

The jar test established:The jar test established:

Jar test determined the optimum dose of ferric Jar test determined the optimum dose of ferric chloride is 4-5 mg/L. Plant adding correct chloride is 4-5 mg/L. Plant adding correct dose (5mg/L) for optimum turbiditydose (5mg/L) for optimum turbidity

The ferric chloride plant dose could potentially The ferric chloride plant dose could potentially be lowered to 4 mg/l if chemical cost is of be lowered to 4 mg/l if chemical cost is of concernconcern

I’d like to introduce Bob JollyI’d like to introduce Bob Jolly

Relief Control Center OperatorRelief Control Center Operator

Anyone who has done much Anyone who has done much jar testing has a story of jar testing has a story of frustration to sharefrustration to share

You can be very diligent in You can be very diligent in your jar testingyour jar testing

Still not match the real world Still not match the real world (plant)(plant)

Jar tests that don’t match the Jar tests that don’t match the real world are of little value!real world are of little value!

And Now For A Curveball ….And Now For A Curveball ….

Reasons Jar Test Results May Not Reasons Jar Test Results May Not Match Actual Plant ConditionsMatch Actual Plant Conditions

Plant chemical feeders may not be feeding Plant chemical feeders may not be feeding correctlycorrectly

Plant mixers may be turning at the wrong speed Plant mixers may be turning at the wrong speed or could be plated and inefficient (or missing!!)or could be plated and inefficient (or missing!!)

Short circuitingShort circuiting Sample chemicals may be incorrectly mixedSample chemicals may be incorrectly mixed Incorrect calculations for jar test settingsIncorrect calculations for jar test settings Many, many moreMany, many more

Performance Based TrainingPerformance Based Training

8 Iowa water utilities & DNR reps8 Iowa water utilities & DNR reps Process Applications, Inc.Process Applications, Inc. Learning about treatment plant optimizationLearning about treatment plant optimization

Set goals for plant performanceSet goals for plant performance Used tools to measure and trend actual plant Used tools to measure and trend actual plant

performanceperformance Learned to use “Special Study” approach to make Learned to use “Special Study” approach to make

improvements in plant performanceimprovements in plant performance

Jar Test CalibrationJar Test Calibration One type of special study is a jar test calibrationOne type of special study is a jar test calibration

Actually a series of special studiesActually a series of special studies

A common sense approachA common sense approach Each unit process is studiedEach unit process is studied

Do jar test results match the plant?Do jar test results match the plant? If not, why not?If not, why not? When results match, you are ready to add variablesWhen results match, you are ready to add variables

““Jar test calibration” = efforts to achieve similar Jar test calibration” = efforts to achieve similar results between plant performance and the jar results between plant performance and the jar testtest

Steps will vary for different plantsSteps will vary for different plants McMullen Treatment PlantMcMullen Treatment Plant

Four steps:Four steps: Quality control evaluation (calibrating the calibrator)Quality control evaluation (calibrating the calibrator) Rapid mix calibrationRapid mix calibration Flocculation calibrationFlocculation calibration Sedimentation calibrationSedimentation calibration

Jar Test CalibrationJar Test Calibration

Quality Control EvaluationQuality Control Evaluation

Two identical jars are tested side-by-sideTwo identical jars are tested side-by-side Flocculation is a good testFlocculation is a good test

Record all results and observationsRecord all results and observations SpreadsheetsSpreadsheets Pencil/paperPencil/paper

Results should agree within +/- 15%Results should agree within +/- 15% If results do not agree:If results do not agree:

Work on improving testing and sampling techniquesWork on improving testing and sampling techniques Retest - Don’t go to next step until you have this one Retest - Don’t go to next step until you have this one

downdown



Rapid Mix CalibrationRapid Mix Calibration Use six jarsUse six jars All mixed at the calculated speed and durationAll mixed at the calculated speed and duration Raw water samples are dosed with ferric chlorideRaw water samples are dosed with ferric chloride

1 jar with no ferric chloride (control)1 jar with no ferric chloride (control) 2 jars dosed below plant setting2 jars dosed below plant setting 1 jar dosed at plant setting (25 mg/L)1 jar dosed at plant setting (25 mg/L) 2 jars dosed above plant setting2 jars dosed above plant setting

Rapid Mix CalibrationRapid Mix Calibration Jar pHs checked after mixing periodJar pHs checked after mixing period Compared to plant pHCompared to plant pH pH of jar 4 and plant should matchpH of jar 4 and plant should match

Rapid Mix CalibrationRapid Mix Calibration

Rapid Mix CalibrationRapid Mix Calibration

Possible Causes of DifferencesPossible Causes of Differences Improper dosing of jars.Improper dosing of jars.

Check calculationsCheck calculations Are the dispensers functioning properlyAre the dispensers functioning properly

Chemical feed pumps not feeding correctlyChemical feed pumps not feeding correctly Check calibration of feed pumpsCheck calibration of feed pumps

Determine cause of differencesDetermine cause of differences Repeat jar test calibration to verify resultsRepeat jar test calibration to verify results Record all setting for use in “calibrated” jar testRecord all setting for use in “calibrated” jar test

Flocculation CalibrationFlocculation Calibration Use one 2 L jarUse one 2 L jar

Sample from flocculation basin influentSample from flocculation basin influent

Add chemicalsAdd chemicals Lime and lime sludgeLime and lime sludge

Mix at proper speed and durationMix at proper speed and duration

Flocculation CalibrationFlocculation Calibration At end of mixing time, wait for water to stop At end of mixing time, wait for water to stop

moving, then start timermoving, then start timer Grab turbidity samplesGrab turbidity samples Be sure to flush sample tap before each sampleBe sure to flush sample tap before each sample Generate settling curveGenerate settling curve

Flocculation CalibrationFlocculation Calibration Take sample of flocculation basin effluentTake sample of flocculation basin effluent

Handle this sample carefully so floc is not damagedHandle this sample carefully so floc is not damaged

Use 2 L jarUse 2 L jar Grab turbidity samplesGrab turbidity samples Generate settling curveGenerate settling curve Compare settling curves of the two jarsCompare settling curves of the two jars

Flocculation CalibrationFlocculation Calibration


Possible Causes of DifferencesPossible Causes of Differences Many variables act on this settling curveMany variables act on this settling curve

Mixer speedMixer speed Mixing timeMixing time Chemical feedsChemical feeds Short circuitingShort circuiting ““Disturbed” sample of flocculation basin eff.Disturbed” sample of flocculation basin eff.

Determine cause of differencesDetermine cause of differences Repeat jar test calibration to verify resultsRepeat jar test calibration to verify results


Change only one variable at a timeChange only one variable at a time when when retestingretesting

This will likely require multiple attemptsThis will likely require multiple attempts Record all settings for use in actual “calibrated” Record all settings for use in actual “calibrated”

jar testjar test

Sedimentation CalibrationSedimentation Calibration

Use three 2 L jarsUse three 2 L jars Sample from a calibrated jar test of flocculation Sample from a calibrated jar test of flocculation

process (preferred)process (preferred) Can use plant sample if necessaryCan use plant sample if necessary

When water stops moving, clock startsWhen water stops moving, clock starts Collect 12 samples over 30 minutesCollect 12 samples over 30 minutes

Alternate jarsAlternate jars 4 samples/jar4 samples/jar



Create a settling curveCreate a settling curve Determine the average sedimentation basin Determine the average sedimentation basin

effluent turbidityeffluent turbidity Find point on graph where the turbidities match Find point on graph where the turbidities match The time at that point is “calibrated” The time at that point is “calibrated”

sedimentation time for our jar testsedimentation time for our jar test


Possible ProblemsPossible Problems

After 30 minutes, the settling curve turbidity may After 30 minutes, the settling curve turbidity may not have dropped to the actual plant turbiditynot have dropped to the actual plant turbidity

Possible ProblemsPossible Problems

In the plant, flocculation continues for a time in In the plant, flocculation continues for a time in the sedimentation basinthe sedimentation basin

This may result in better settling in the plantThis may result in better settling in the plant In this situation we could:In this situation we could:

do another test adding some slow mixingdo another test adding some slow mixing 5-10 rpm for several minutes5-10 rpm for several minutes begin sample collection for developing settling curvebegin sample collection for developing settling curve

Record all procedures used for the “calibrated” Record all procedures used for the “calibrated” jar testjar test

Jar Test CalibrationJar Test Calibration

Should greatly reduce discrepancies between jar Should greatly reduce discrepancies between jar test results and actual plant conditionstest results and actual plant conditions

Makes the jar test a Makes the jar test a muchmuch more useful tool more useful tool Confidence in your results will make the extra Confidence in your results will make the extra

time spent worthwhiletime spent worthwhile

Elevate jars to keep floc suspendedElevate jars to keep floc suspended Make sure chemicals are freshMake sure chemicals are fresh Make sure you know:Make sure you know:

Current chemical feed ratesCurrent chemical feed rates Concentration of chemical being fedConcentration of chemical being fed

Add sludgeAdd sludge Based on plant sludge concentrationBased on plant sludge concentration

Use a timerUse a timer Don’t leave pH probe in jarDon’t leave pH probe in jar Record everything!!Record everything!!

Lessons LearnedLessons Learned

Lessons LearnedLessons Learned Thoroughly clean jars and mixers to remove Thoroughly clean jars and mixers to remove

chemical residuechemical residue 2L square jars preferred2L square jars preferred Coagulant dosingCoagulant dosing

Eppendorfs & Syringes preferredEppendorfs & Syringes preferred Dose close to paddle shaftDose close to paddle shaft Dose in sequence or togetherDose in sequence or together

SamplingSampling Flush sample taps slowly beforeFlush sample taps slowly before

samplingsampling When collecting numerous samples,When collecting numerous samples,

get helpget help

QUESTIONS?QUESTIONS?

SummarySummary

Jar TestingJar Testing• Experimental methodExperimental method• Plant conditions simulated in laboratory environmentPlant conditions simulated in laboratory environment• Allows experimentation without affecting water qualityAllows experimentation without affecting water quality• Allows evaluation of individual processes or entire Allows evaluation of individual processes or entire

treatment plant treatment plant

• MUST CALIBRATE FOR ACCURACYMUST CALIBRATE FOR ACCURACY

ContactsContacts Mark Moeller Mark Moeller

[email protected]

Bunton, Jennifer Bunton, Jennifer [email protected]

Bob JollyBob Jolly [email protected]@dmww.com

Barb DuffBarb Duff [email protected]@dmww.com

Documents

Jar Test Overview Calibration