Materials:pHmeter,pHtestpaper'standardacid'standardbase'

Proced ure

1. Check the pH of a small aliquot of the sample by wetting a pH test paper and

comparing the colour combinaiions to those shown on the case (Take care not tor contaminate PaPer in case')

2. Calibrate the pH meter by following the procedyrg outlined on the instruction,sheet

beside the meter unless told otherwiJe. Ae sure that buffers are being stirred when you

perform the calibration and that when you change buffers you thoroughly rinse the

probe into a waste beaker and blot Jri to tn"t yiou do not contaminate other buffers oryour samptes fttoimally, the twolouffers that are chosen for calibration will bracket

your

sample ie if sample is less than 7, unJ irrun use buffers 4 and 7 to calibrate; if above 7'

then use buffers 7 and 10'

3. After calibration is Complete, rinse & dry probe, place a beaker containing the sample

and stir-bar on the stir-prate, to*"r-fronl,ttrtn on stirrer and obtain a stabre reading.(Donot allow the stir bar to hit the probe) Record value in following table'

4. Rinse probe when you are finished and leave immersed in pH 7 buffer for storage

Observations:

crv

Experiment - 1

DET ERMINAT ION

To determine the pH value of wastewater

Sample 1 SamPle 2

ENVIRONMENTAL ENGG. & SCIENCE

LAB MANUAL

OF pH VALUE

using pH meter.

pH by test PaPer

pH by pH meter

ExPerinrent - 2

DETERMINATION OF ALKALINITY

Aim: To determine the Alkalinity of wastewater by titratron method

Materials: pH meter, magnetic stirr:er, phenolphthalein. and other indrcators' standardacid, standard base, burettes and stand, graduated cylinders, beakers' flasks' colourcomparator.

Procedure:

1. Rrnse and fill a labelled burette with standard acid solution.

2. Measure 100 ml Of water sample into a clean, sample-rinsed graduated cylinder andtransfer to an Erlenmeyer flask. ln order to remove any free residual chlorine (whichinterferes with the indicator colour response), add 1 drop of 0 1 N sodium thiosulphateto the samPle. Add a stir-bar.

3. Add a full dropper of phenolphthalein (P) indicator and if the solutron stays pink orred titrate until just colourless.

4 Record the burelte reading in the following table'

5. lf sample is highly alkaline (titration goes over one burette full) dilute the sample andtitrate again. Apply dilution factor to obtain final result.

Observations:

, Sample volume (ml), V=

lnitial burette reading

Alkalinity end-point reading (ml) .---.-.----..-.---.-

Net AlkalinitY titrate (ml), A=

Calculations:

mg CaCO3 /LWhere: A = ml

=A x N x 50,000/V ml of samPlestandard acid used

N = normality of standard acid

ExPeriment -3

DlssoLVED OXYGEN (DO)

Aim: To measure the amount of Dissolved Oxygen tn wastewater

Materials: Raw sewage and final efiiuent samples, dilution water, alkaline-iodide-azidereagent, manganous Julfate, concentrated sulphuric acid starch indicator, 0.025 Nsodlum thiosulphate, thermometers, BOD bottles, 10-ml gra'duated pipettes, burettestand with burettes, 250-ml graduated cylinder, 500-ml Erlenmeyer flasks

Note: You are going to measure DO on four different Iiquids using two differentmethods. The four liquids are cold tap water, aerated ditution water, raw sewage andfinal effluent. 'By chemical titration (Winkler - the azide modification of the iodometric method)

Proced ure:

1. Fill four BOD bottles with the four samples (cold tap water, aerated dilution water, rawsewage or influent and final effluent), right to the top and place stopper on bottle' (Fillcarefully, taking care not to entrain additional air. For the cold tap water sample,submerge the hose in the bottle and allow the water to overflow for 15-30 seconds oruntil water is cold).

2. Determine DO, using the DO probe and meter, for each of the four samples'lnstructions on the use of the probe will be given in the lab. Record the temperature ofeach sample using the DO meter. You can save these bottles for the Winkler method.

\4rtNKLER T ITRATION (Azide mod ification)

1. Fill a BOD bottle with each of the four samples (or use ones saved from A - whichmay have to be topped up to exclude air). Stopper the bottles without trapping any airOubntes (lrft stopper to let bubbles out or add a little extra sample if air bubbles arb seeninside)

2. place the bottles in the sink and one at a time remove the stopper, add i lone; mt ofmanganous sulfate reagent using plastic dropper provided (keeping the dropper tip justbelow the surface) and-quickly replace the lid. To the same bottle, add 1 ml'of alkaline-iodide-azide solution, again quict

demonstrated, to thoroughly mix contents. Set bottle back in stnk Repeat the sameprocedure with the other three samples.

3 Allow the floc to settle to about 1/3 the bottle volume, invert several times again toremix and allow floc to settle again. When the floc has settled the second time to about1/3 bottle volume, remove the stopper, add 1 ml of concentrated H2S04 and quickly re-stopper. Tip out the liquid from the area around the stopper and invert several times tomix thoroughly. The chemical floc should completely dissolve. (Note biological solidsoriginally present in the sample will not drssolve.) Repeat for other three samples.

4. Transfer 201 ml of each sample bottle (do one at a time) to a 500 ml conical flask.Use the specially marked volumetricflask to dispense the 201 ml

5. Titrate this volume with 0.025 N Na252O3 untii only a faint yellow or "straiv" colourremains. Note: if solution already seems pale yellow add starch rrght away. Add enoughstarch solution to give a strong blue colour (one dropper full) and continue to titrate,drop-wise, until the flrst complete disappea"rance of the blue colour. Neglect anyreappearance of the blue colour. Record the volume of titre

Observations:

Sample source

Raw Sewage Bottle numberSample volume (ml)lnitial DO (mg/L)Final DO (mg/L)

Final Effluent Bottle numberSample volume (ml)lnitial DO (mg/L)Final DO (mg/L)

Qilution water Bottle numberSample volume (ml)

---*lnitial DO (mg/L)

_

Final DO (mg/L) _

ExPeriment - 4

BtocHEMlcAL OXYGEN DEMAND (B.O.D)

Aim: To calculate the value of Biological Oxygen Demand (B.C D) in wastewater.

Materials: Raw sewage and final effluent samples, dilution water, aikaline'iodjde-azrdereagent, manganous sulfate, concentrated sulphurrc acid, starch indicator, 0.025 Nsodium thiosulphate, thermometers, BOD bottles, 1O-ml graduated pipettes, burettestand with burettes, 250-ml graduated cylinder, 500-ml Erlenmeyer flasks.

Proced u re:

1. Using the volumes and samples provided by the instructor, carefully meaSure thesamples (Raw and Effluent) into BOD bottles. Two dilutions will be made for eachsample and each dilution will be in duplicate for a total of eight bottles plus one bottle forthe blank (mentioned in Step 4). Be sure to record the bottle numbers and samplevolumes on the following table - do not write on the bottles and do not use the numberson the lids.

2 Carefully top up the BOD bottles with DILUTION WATER, to bring the levels abovethe ground glass neck of the bottle. Try not to aerate the contents by keeping the flllingtube below the surface of the liquid in the bottle or carefully running the water down theside of the bottle. Fill one BOD bottle with DILUTION WATER alone. Because you wantto be sure that the dilution water has no BOD, be careful not to contaminate itwithsample. The blank is used to check that the dilution water has neglrgible BOD.

3. Measure the lnitial DO in all 9 bottles using a probe and meter. Record the meternumber and use same one for final measurements.

4, Stopper the BOD bottles, being sure to exclude any air bubbles that might be trappeduncjer the stopper by adding a little dilution water if necessary All bottles should haveliquid in the well around the stopper - if not add some dilution water (or distilled water) tothe well. Place plastic caps over all bottles. These caps are designed to prevent theevaporation of ihe liquid around the stopper, thereby maintaining a water st4al for eachbottle.

5. Place BOD sets in the 20o C incubator for five days.Note: Each group should have 6 BOD bottles in the incubator.

G After five (or six) days, remove bottles and measure the final DO, preferably using thesame meter and probe used to get IDO reading. Calculate the S-day (or 6-day) BpD

showing sample calculations. There should be negligible BOD in the Dilr-rtion'water butif there is a significant BOD then it will have to be subtracted before the dilution factor isapplied in the calculation. lf the dilution water BOD is greater than 1 ppm it mayindicate the dilution water had been contaminatedObservations: /Sample source:

Raw SewageSample volume (ml)lnitial DO (mg/L)Final DO (mgiL)

Final Effluent Bottle numberSample volume (ml)lnitial DO (mg/L)Final DO (mg/L)

Dilution water Bottle numberSample volume (ml)lnitial DO (mgiL)Final DO (mgll)

BOD5 Calculation

When dilution water is not seeded (our water is not seeded for this exercise),fr

-.lliilil: ''] *'-F

When seeded water is used:

Bottle number

!.rrl -'

/l't - i':' -"!'t - r*-'-l'a r-j

-

D1 = DO *0,,r,"0 sampleimmeOiately after preparation, hrg/LD2 = DO of diluted sample after 5 d incubation at 2OoC, mg/LP - decimal volumetric fraction of sample usedB1 = DO of seed control before incubation, mg/L82 = DO of seed control after incubation, mg/L.

and f = ratio of seed water in diluted sample to seed tn seed control=(% seed in diluted sample) / (%seed in seed control)

where.

Summary

Raw Sewage Diln. 1Raw Sewage, Diln. 2Final Effluent. Diln. 1

Averaoe

Final Effluent, Diln. 2 Average

Percentage BOD reduction through treatment plant

ExPeriment - 5

ELECTRICAL CONDUCTIVITY

Aim: To determine the Electrical Conductivity of Wastewater.

Materiai: Conductivity Meter, Tap water, Sewage water Final Effluent

Procedure:Once the instrument has been standardized, the userwill now be ready to makedeterminations of unknown conductivity values.

Select RANGE either Auto or appropriate manual range Set REFERENCETEMPERATURE if different than 25"C Set TEMPERATURE COEFFICIENT if differentthan 1 .91o/o (tf unsure, leave a|1.91%).Rinse Conductivity Cell in de-ionized (Dl) water and gently shake off excess water.Place the cell in a sample of the unknown solution to be measured.Move the cell in an up and down motion a few tirnes (agitate cell) to dislodge any airbubbles.Wait until reading on display becomes stable then record measurement.

Standardize to Cell ColE;tant (K)

One Beaker Method.

1. Fill one clean beaker with a known value of calibration solution. Make sure thecalibration solution is not expired and has been stored properly if not new. Do notfill beaker more than half way. This will prevent spilling over when cell is inserted.

, 2.lf practical hold the calibration solution aI25"C

3. Dip Cell into beaker containrng only Dl water and soak cell for one to two minutesThis helps to wet the plates of the cell. Remove Cell from Dl water and gentlyshake off excess water.

4. Next dip cell into the beaker that contains calibration solution of known value.Gently move up and down a few times to dislodge any air bubbles that may havebecome trapped. Wait for reading to become stable then press the Parameter[>Kl key one time "Calibrate" will appear in display. Use the Set key and press up[A] or down [V] to make the display read the value of the solution. Wait a fewseconds and the instrument will prompt the user to save the setting Press the

parameter Dt{ key to save. Fill in the information requested on the CilibrationData Form and note the cell constant (K). The instrument is now standardized(calibrated)

Observations:

Electrical Conductivity of Raw SewageElectrical Conductivity of Tap WaterEieetrical Conductivity of Final Effluent

ExPeriment - 6

TURBIDITY

Aim: To determine Turbidity of wastewater using Turbidity meter

Material: Turbidity Meter, Tap water, Sewage water, Final Effluent

Proced ure:

Turbidity measurements provide data on the concentrat.ion of undissolved, iuspendedparticlei present in a liquid phase. The determined particle concentration is used forpror"r, monitoring and optimization e.g. to control biomass growth, crystallization andfiltration processes or concentration measurement of solid matters in wastewater'

PART A: Hach Turbidimeter1. place the sealed standard into holder and place light shield cap over standard' Makesure that the cell riser is placed in the cell holder assembly before the standards in the0-100 and o-1000 FTU ranges. Adjust the calibration knob to the correct reading.'2. Fnl the sample cell with undiluted sample and read the turbidity lt may be necessaryto recalibrate using the appropriate standard range ie if the sample rs below'10'calibrate using tnJto FT'U standard. lf the sanrple rs above 1000, it will be necessary todilute usrng flltered sample water not distilled water (which might dissolve some of theturbidity in the samPle).3. Rinse out the sample cell and record your reading in the following table DO NOTTURN THE TURBIDIMETER OFF

PART B: Hellige Turbidimeter1. Carefully fitl ihe 20 mm viewing depth tube to the mark with sample. Lower thepiirnger inlo the liquid making sure no bubbles are trapped under the plunger and theiop iI dry. Wipe the outside of tne tube to dry it and place it in the turbidimeter (in thecircular groove of the mirror unit). Note that ihe rectangular door mirror is ilosed, thatthe fllter selector shows "none" and that bulb B is in use' Close the door and switch onthe light2. lmmediately balance the light intensity of the central.spot with the surroundingobservation field by turning tlie dial on the right-hand side of the instrument Take thereading where the dark ce"ntral part first merges with the surroundtng field. lf you taketoo lorig, the turbidity may start to settle and condense on the bottom of the tube'3. Read the scale on the dial, record the number and refer to the approprrate graph todetermine the turbidity as mgil Si02.

PART C: Jackson Candle Turbidity 'this will be shown to class but noti nd ivid ually perfoimed.1. Be sure that the calibrated tubes are clean before adding samples !o th9 llbes ooNOT PLACE AN EMPTY TUBE IN THE TUBE HOLDER WITH THE CANDLE LIT -adding liquid to a hot tube will cause it to shatter. Try to be quick and not burn thecandles more than a few minutes at a time. Pinch all excess charred wick with fingersbefore lighting or soot may be deposited on the glass tubes, obscurrng vision'2. pour sample into the tube in smafi increments until you can no longer distinguish theshape of the candle flame. Remove about 1O mls of sample by pipette and slowlydispense this aliquot back into the tube until the shape of the flame is no longerdisiinguishable. (This allows you to make a more gradual and accurate approach to theend-point.)3. Remove the glass tube from thesample. Note that there are severalvalue in following table as J.T-U.s.

holder and read the turbidity at the meniscus of thedifferent scaies on the side of the tube.'Record

Observations:

Turbidity of Raw SewageTurbidity of Tap WaterTurbrdity of Final Effluent

ExPeriment - 7

TOTAL HARDNESS DETERMINATION

Aim: To determine Total Hardness of grven unknown sample'

Material: Standard EDTA solution, Burette, Erlenrneyer flask, stir-bar, Amrnonra buffer

solution, EBT indicator

EDTA TITRIMETRIC METHOD

1 Rinse andfill a burettewith standard EDTA (O.O1N) solution and record the initialburette reading.

2. Measure out 25 mls ofdistilled water. Pour Into

lnitial burette reading (ml)Net titrant (ml), A=Total Hardness as mg/L caco3 --

Total Hardnessmg CaCO3/L = A x B x 1000/V ml of sample

sample using a graduated cylinder and dilute to 50 ml witha 250 ml Erlenmeyer flask. Add stir-ba t

3. Add 1-2 ml of buffer solution using dropper bottle (3 full droppers) and one aliquot ofTotal Hardness lndicator using the special dispenser on the chemical bottle' The buffer

elevatesthe pH to 10. A pH miuch above 1O promotes CaCO3 precipitate

4. Titrate slowly with EDTA, while stirring, until the reddish tinge disappears from the

solution and a pure blue rematns. Add tie last few drops at 3-5 second intervals so thatyou do not "overshoot" the end-point. A paper towel placed under the flask will facilitate

this determination. complete the trtration within 5 minutes to minimize the tendencytoward caco3 precipitation. lf a ppt does form withrn the 5 minutes' it may benecessary to repeat ihe titration with the sample diluted 1 to 1 (again) with distilledwater. Alternatively, if the approximate hardness is known (by unsuc,cessful attempts)'add 90% of the titiant to the sample before adjusting the pH with buffer' '

5. Record the final burette reading in the following table'

TOTAL HardnessSample volume (ml), V=Final burette reading (ml)

WhereA = ml titrant for samPleB = mg CaCO3 equivalent

endPoint = 1.0to '1.00 ml EDTA titrant at the calcium rndicator

ExPeriment'8

CALCIUM HARDNESS DETERMINATION

Aim: To determine Total Hardness of glven unknown sample'

Material: standard EDTA solution, Burette, Erlenmeyer flask' stir-bar' Ammonia buffer

solution, EBT indicator, Sodium Hydroxide (NaOH)

EDTA TITRIMETRIC METHOD

1. Refill the burette with EDTA titrant and note the initial reading I

2 Measure out 50 ml of sample into an Erlenmeyer flask and add 2 0 ml of 1 N NaOHsorution (use 3 droppers fuil), or a vorume sufficient to produce a pH of 13-14 (designedi" Jr".ipliute gre riagnesium as a hydroxide). Add a stir-bar and stir to mix

3. Add one aliquot of the calcium Hardness lndicator and titrate with EDTA siowly, with

continuous stirring to a pure blue end-potnt'

4,Recordthefinalburettereadinginthefollowingtable.t

CALC IU MSample volume (ml)' V=Final burette reading (ml)lnitial burette reading (ml)Net titrant (ml), A=Calcrum as mg Ca++/LCalcium hardness as mg CaCO3/L

CalciummgCa/L = AxBx40x0,BlVml of samPlewhere. A = ml titrant for samPleB = mg CaCO3 equivalent to 1'00 ml EDTA titrant at10

Calcium Hardness

the calcium indicator endPotnt =

mg CaCO3 /L = A x B x 1000 / V*["r". A = ml trtrant for samPleB = mg CaCO3 equivalent to 1'0010

ml of samPle

ml EDTA titrant at the calcium indicator endpoint'=

Limit test for lron.

AIM: To perform Limit test for iron from given unknown sample

Requirements:

2Oo/owlvcitric acid solution, thiogrycollir acrd solution' HCI std lron solutron (20

ppm=O 0173"h wlv)

Nessur cylinder, beaker, pipette' stirring rod' etc

Principle: IThe limit test for iron is based on the reaction between of

iron in ammonical soiution

in presence of citric acid with thioglycoline acid when a pale prnk to deep reddish purple

color is framed due to ferrous compound. The colour produced from a specific amount

of substance from the test is compare by viewing vertically with a std [ferrlc Ammonium

sulphate).lf the colour from test solution is less than the standard then the sample

possesthetest.Citricaciddoesnotallowtheprecipitationofironbyammoniaformtnga complete complex with it. The colour due to ferrous compound

gets destroyed'by

oxydisingagentandalkalies'Thestatofoxrdaontionofironhasbeeninmaterialasircn.ltli; gets-reduced to iron (ll) by thioglycoric acid

Thioglicoric acid (HS) CHzCOOH is a useful analogous of glycorrc acid cHzoH

CooHwhichispreparedbytheactionofpotassiumhydrogensulphiteormonocarboacetic acid.

ExPeriment - 9

LEST TEST FOR IRON

cHzCt cooH + KSH CH2(SH)COOH + KCL

Thisisverysensitiveinferenceofothermetalcationsrselimrnatedbymaskinguseof20% Citric acid which form a complex with other metal

cations

FeZ' + 2

Ferrous thioglicollate is colourless in acid or neutral solution ln acidic media Fe2+

(Fei-ric) is oxidized to Fe3* (Ferrous) in presence of thioglycorric acid 'Hence the soiution

become colourless .The purple colour rs developed only in the presence of AIkali'

Procedure:

Test solution : Take 1gmvrgorous stirring then acid 2mlof thioglycoric acid solution'

of samPle add aPProximatelY2Ook wlv iron free acetic acid

4Oml distill water withsolution followed bY 2 droP

Mixed well-made alkaline with ammonia and volume adjusted to 50 ml marks on

nesselercylinderallowittostandfor5minandcolourdeveloped'viewedverticallyandcompared with standard solution'

Standard solution:

Take 2ml of 20 ppm (0.0173%) (Ferricammonium sulphate) iron std solution add 'Approx .40 ml distilled water by constant stirring then add 2 ml of

2oo/o wlv citric acid

followed by 2 drop of thiuoglycollic acid soltttion Mixed well' made alkalineyith

ammonia and volume adjusted to 50 ml mark on N/c allow to stand for 5 min and colour

developed, viewed vertically and compared with test solution'

Result.ThesamplepaSses/doesnotpassthelimittestforlron.

Preparation of reagent-(250mI) :

50 gm. citrrc acid in 250 ml of wate r i.e.ZOo/ow/v citric acid solution '

(2) Dil. Ammonia solution: 10% wiv solution (250 ml)

(3)std.lronsolution-(2Oppm):WeightaccuratelyO.OlT3gm.offerrrcammoniumsulphate dissolve in 10 ml of 0.1 N HCL and make volume up to

100m1

ExPeriment - '10

,

LIMIT TEST TOR STJLPHATE

Aim:ToperformthelimittestofSulphatefromgivensample

Requirements: Nesslers cylinder, Pipette, Glass Rod, Ethanolic StandardSolu., Dilute Hydrochloric acid, Barium Sulphate Reagent'

Dilute HCI -

5N -

Dissolve 4.3 ml of conc. HCI in D.W. to make 10 ml'

Ethanolic sulphate solution 1o ppm - 0.0181 a/o wlv Kzsoa in D.w' and dilute '10 ml to

'100 ml with 30% ethanol.

Barium chlorrde solution: 25o/owlv (Take 2 5 gm and dissolve in 10 ml of D w )

Standard sulpate Solution: 10 ppm - O 0181% KzSOa in D W and drlute 1O ml to i00 mlwith Distilled water

Aceticacid-5M-Take2.Bml ofglacial aceticacidmakesupthevol upto'1Oml withDrstilled water.

Barium sulphate Reagent - The BaClz solution along with Ethanolrc sulphate reagent

and acetic acid is known as Barium sulphate Reagent.

Procedure:

standard solution: Take 15 ml of Standard sulphate solution (10 ppm) in'place of Test,oir,ion (Specified quantity of substance in 15 ml distilled water) To this add'1'5ml ofethanolic sulphate standard solution (10 ppm SOo2-), mix and allow standing for ami.nute. Add a solution of the specified quality (1 gm) of the substance being examinedi; .ts ,' of water and 0.15 ml of 5M acetic acid. Make up the volume to 50 ml withwater, stir immediately with a glass rod and allow standing for 5 minutes'

Test Solution: Take 1.0m| of a25.Oo/o wiv solution of barium chloride in a Nesslercylinder. To this add 1.5m| of ethanolic sulphate standard solution (10 ppm SOq2 )' mixandallowstandingforaminute.Addasolutionof thespecifiedquality(1 9m) of thesubstance being examined in 15 ml of water and o.'15 ml of 5M acetrc acrd' Make up

the

volume to 50 ml with water, stir immediately wrth a glass rod and altow standing for 5

minutes.

Sulphate

I transverselY against a blackObservations: Any opalescence produced when

u'"*":,::]::::^:;;.background is not more intense then that obtained

by sulphate standard solutron (10

;;E;;") in the same mannerResult;ThesEmplepasses/doesnotpassthetimittestforSulphates''i