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CE 6611-ENVIRONMENTAL ENGINEERING LABORATORY

MANUAL

PREPARED By

R.MANIKANDANLECTURER

DEPARTMENT OF CIVILENGINEERING

SEMBODAI RUKMANIVARATHARAJAN ENGINEERING COLLEGESEMBODAI-614 820.

CE6611-ENVIRONMENTAL ENGINEERING LABORATORY MANUAL

CE6611 – ENVIRONMENTAL ENGINEERING LABORATORY

OBJECTIVES:

To understand the sampling and preservation methods and significance of characterization of wastewater.

LIST OF EXPERIMENTS:

1. Determination of Ammonia Nitrogen in wastewater.

2. Coagulation and Precipitation process for treating waste water

3. Determination of suspended, volatile, fixed and settleable solids in wastewater.

4. B.O.D. test

5. C.O.D. test

6. Nitrate in wastewater.

7. Phosphate in wastewater.

8. Determination of Calcium, Potassium and Sodium.

9. Heavy metals determination - Chromium, Lead and Zinc. (Demonstration only) Total =45 periods

REFERENCES

1.Standard methods for the examination of water and wastewater, APHA, 20th Edition, Washington, 1998


LIST OF EXPERIMENTS

Sl. No.

Description of Equipment Quantity

1Oxygen analyzer

2Spectrophotometer

3Ion – selective electrode

4Sodium Potassium Analyzer – Flame Photometer

5Gas Chromatography

6Atomic absorption spectroscopy (Ni, Zn, Pb)

7 Nephlo - turbidity meter

8 BOD Analyser

9 COD Analyser

10 Jar Test Apparatus


SL.NO

DATE EXPERIMENTS

MARK

SIGN


DETERMINATION OF AMMONIA NITROGEN

Exp No: 1Date

AimTo determine the amount of Ammonia Nitrogen present in the given sample.

PrincipleAmmonium ion reacts with Nessler’s reagent (K2HgI4) to form a brown

colour substance, and can be determined colorimentically. Most of the natural waters and wastewaters have interfering substances, therefore, the steam distillation of ammonia becomes essential.

Apparatus required1. Measuring jar2. Conical flask3. Burette4. Pipette

Reagents1. Phosphate buffer solution2. Boric acid3. Methyl orange indicator4. Sulphuric acid 0.02N

Procedure1. Take 50ml of the sample in a conical flask.2. Add 5ml of phosphate buffer solution and 10 ml of boric acid solution.3. Add 3 -5 drops of methyl orange indicator.4. Titrate against 0.02N of sulphuric acid till the end point is changes from

orange to yellow.

Calculation

NH3- N2 mg/l = ml of H2SO4 x 0.28 x1000-------------------Ml of sample


Tabulation

S.No Vol of waterInitial burette

Final burette Concurrent Vol of

sample reading (ml) reading (ml)burette reading

sulphuric

(ml) (ml)acid (ml)

Result

The amount of Ammonia Nitrogen present in the given sample is -------- mg/l.


DETERMINATION OF OPTIMUM COAGULANT DOSAGE

Exp No:2Date

AimTo find out the optimum coagulant required to precipitate turbid particles

present in the water.

Principle

Metal salts hydrolyse in presence of the natural alkalinity to form metal hydroxides. The divalent cations can reduce the zeta-potential, while the metal hydroxides are good absorbents and hence remove the suspended particles by enmeshing them.

Apparatus Required1. Jars mixer2. Turbid water3. Beakers4. Pipettes5. Turbidity meter6. pH meter

ReagentsAlum solution

Procedure1. 200ml of water sample is taken in each jar. Increasing dose of alum (1%)

i.e. 1gm/100ml of distilled water added to slowly for 15min and allowed to stand for 15min.

2. The jars are observed and the settling of sediments are noted. The quality of alum added to the jar containing the clearest solution is noted.

3. Take the sample out of beaker and test for turbidity in each trial plot the curve on x and y axis of the graph sheet. Take the alum dosage in ml along x axis and turbidity along y axis.


ObservationsRaw water turbidity (NTU) =Raw water pH =Raw water alkalinity (mg/l) =

Sample details Dosage of Residual pH Alkalinity mg/lcoagulant turbidity

ResultThe optimum dosage of coagulant required to remove turbidity in the given

water sample is…………………….


DETERMINATION OF SUSPENDED, VOLATILE AND FIXED SOLIDS

Exp No: 3Date

AimTo determine the amount of total solids, suspended solids and dissolved

solids in given sample.

Apparatus Required1. Muffle furnace2. Hot plate or water bath oven3. Evaporating dish

PrincipleResidual after the evaporation and subsequent drying in oven at specific

temperature (103o to 105o C) of a known volume of sample is called as total solids.

The suspended solids can be found by filtering the water sample and weighing the residue left on the filter paper.

Procedure1. Take an evaporating disc of at least 100ml capacity liquid at 550 to 50o in

a muffle furnace for about an hour cool in a desicator and weigh it as W1.2. Evaporate 10 ml of unfiltered sample few more in the case the solids are

less than 250mg/lt in evaporating dish on a water bath over list plate lowing temperature are not more than 98oC.

3. Cool in a desicator and weigh the residue left in a dish.4. Weigh the filter paper without any moisture (W5)5. Dry the paper in the oven then weigh the residue left in paper (W4).


CALCULATIONS

Total solids (mg/l) = (W2-W1) x 1000-----------------------

V

Suspended Solids (mg/l) = (W4 – W3) x 1000-----------------------

V

Dissolved Solids = Total solids – Suspended solids

Result

Total Solids = ---------------- mg/l

Suspended solids = ------------ mg/l

Dissolved solids = --------------- mg/l


B.O.D TEST

Exp No: 4Date

AimTo determine the BOD in the given wastewater sample.

Apparatus RequiredBOD incubatorBOD bottle (300ml)

PrincipleIf sufficient oxygen is available in wastewater, the useful aerobic bacteria

will flourish and cause the aerobic biological decomposition of wastewater which will continue until oxidation is completed.

The amount of oxygen consumed in this process is the BOD. Polluted waters will continue to absorb oxygen for many months, and it is not practically feasible to determine this ultimate oxygen demand.

Reagents1.Distilled water2.Phosphate buffer solution3.Magnesium sulphate solution4.Calcium chloride solution5.Ferric chloride solution6.Sodium thiosulphate solution

Procedure

1. Mix a known volume (4ml) of a sample of wastewater with a known volume of aerated pure water to make 300ml diluted sample and then calculate the D.O.of this diluted sample.

2. The diluted sample is then incubated for 5 days at 20o C .3. The D.O.of the diluted sample ,after this period of incubation, is again

calculated.4. The difference between the initial D.O. value and the final D.O. value

will indicate the oxygen consumed by the sewage in 5 days .


CALCULATION

BOD5=D.O.consumed by the diluted sample x (volume of diluted sample)----------------------------------

Volume of undiluted sewage

= dilution factor

Observations

S.No Vol of Dilution Initial Final DOInitial Final DO 5 days

sample (ml) ratio DO of of DO of of blank BOD at

sample sample

Blank mg/l

20o

C

mg/l mg/l mg/lmg/l

Result

BOD5 of given sample at 20oC in mg/l


C.O.D TEST

Exp No: 5Date

AimTo find the chemical oxygen demand of given wastewater sample.

PrincipleThe organic matter present in sample gets oxidized completely by

K2Cr2O7 in the presence of H2SO4 to produce CO2 and H2O. The excess K2Cr2O7 remaining after the reaction is titrated with Fe(NH4)2(SO4)2. The dichromate consumed gives the O2 required to oxidation of the organic matter.

Apparatus Required1. Reflux apparatus2. Hot plate/heating mantle3. Burette

Reagents1.Standard potassium dichromate 0.25N2.Sulphuric acid with reagent (Conc.H2SO4 + Ag2SO4)3.Standard ferrous ammonium sulphate 0.1N4.Ferroin indicator5.Mercuric sulphate

Procedure1. Place 0.4gm of HgSO4 in the reflux flask.2. Add 20ml of sample (or an aliquot diluted to 20ml)3. 10ml of more concentrated dichromate solution are placed into flask

together with glass beeds.4. Add slowly 30ml of H2SO4 containing Ag2SO4 and mix thoroughly.5. Connect the flask to condenser. Mix the contents thoroughly before

heating.6. Improper mixing results in bumping and the sample may be blown out.7. Reflux for a minimum period of 2 hours. Cool and wash down the

condenser with distilled water.8. Dilute the sample to make up 150ml and cool.9. Titrate excess K2Cr2O7 with 0.1N Fe(NH4)2SO4 using ferroin indicator.10.Sharp colour change from blue green to wine red indicates the end point.11.Reflux the blank in the same manner using distilled water instead of

sample.


Calculations

Quantity of Fe(NH4)2SO4 added for blank = A mlQuantity of Fe(NH4)2SO4 added for the sample = B ml

COD = (A - B) x normality of Fe(NH4)2SO4 x 8 x 1000---------------------------------------------------------------

Quantity of sample (ml)

Observations

S.NO VolofBurette Reading (ml) Vol of COD of the

INDICATOR

sampleFe(NH4)2SO4 sample mg/l

(ml)Initial Final

( ml)

1.

2.

Result

The COD of the given sample is ------------------


Nitrate in wastewater

Exp No: 6Date

AimTo find the Nitrate nitrogen may be present in small amounts in fresh domestic wastewater

PrincipleIn this experiment, nitrate will be reduced to nitrite with zinc. The nitrite

reactswith sulfanilic acid and N-1-naphthylethylenediamine to produce a red compound.The intensity of the red color is analyzed spectrophotometrically. The amount of zincand the contact period are important.

Special Apparatus

a. Spectronic 20 - spectrophotometer set at 520 nm.b. Filter paper and vacuum filtration apparatus.

Reagentsa. Stock potassium nitrate solution: 0.816 g of anhydrous KNO3 is dissolved inpurified water and diluted to 1 liter to produce a 500 mg/L nitrate solution. 100 mL ofthis solution is diluted to 1 liter to produce the stock 50 mg/L nitrate solution whichwill be used in this experiment.

b. Hydrochloric acid diluted 1:4 1 part con. HCl and 4 partswater.

c. Sulfanilic acid: Dissolve 0.60 g of sulfanilic acid in 70 mL hot purified water, cool,dilute to 100 mL with purified water, and mixthoroughly.

d. Zinc: Add 1.000 g finely powdered zinc to 200 g sodium chloride, NaCl, in abottle and mix thoroughly by shaking for several minutes.

f. N-1-naphthylethylenediamine dihydrochloride reagent:Dissolve 0.60 g N-1-naphthylethylenediamine dihydrochloride in purified water towhich 1.0 mL con. HCl has been added. Dilute to 100 mL and mix. Store inrefrigerator. (Stable for about aweek.)

g. Sodium acetate solution: Prepare 100 mL of 2 M NaC2H3O2.


Procedure:

a. Preparation of standards:

Blank: Measure 50 mL of purified water and transfer to a 250-mL erlenmeyer flask.

2.5 mg/L standard: Add 2.5 mL of stock 50 mg/L nitratesolution to a 100-mLgraduated cylinder. Add purified water and dilute to a volume of 50 mL. Transfer to a250-mL erlenmeyer flask.

5.0 mg/L standard: Repeat the directions for the 2.5 mg/L standard using 5.0 mL of50 mg/L nitrate solution.

10.0 mg/L standard: Repeat the directions for the 2.5 mg/L standard using 10.0 mLof 50 mg/L nitrate solution.

15.0 mg/L standard: Repeat the directions for the 2.5 mg/L standard using 15.0 mLof 50 mg/L nitrate solution.

b. Experimental: Use the following procedure for treating standards as well asriver, lake, well, or sewage water sampl

Note: Treated sewage effluent may require a 5-fold or a 10-fold dilution. A10-fold dilution can be performed by pipetting 5.0 mL of the treated wastewater(sewage) sample into a 100-mL graduated cylinder and adding enough water to bring

the volume up to 50 mL. This 50 mL sample can then be taken through theexperimental and color development procedure. A 10-fold dilution results in adilution factor of 10. Remember to multiply the concentration obtained for thediluted sample by a factor of 5 or 10.To a 50.0-mL water sample in a 250-mL erlenmeyer flask, add 1.0 mL of diluteHCl (1:4 dilution) and 1.0 mL sulfanilic acid reagent and mix thoroughly. In a dry10-mL graduated cylinder, measure one mL of the Zn/NaCl granular mixture and addit to the erlenmeyer flask.

Swirl the flask for seven minutes. Filter with a vacuum flask after the sevenminute swirling period. Rinse the erlenmeyer flask well with purified water and pourthe filtered water sample back into the flask.


Color Development: Add 1.0 mL N-1- naphthylethylenediamine dihydrochloridereagent to the filtered sample and mix. Add 1.0 mL of 2 M sodium acetate solutionand mix. Allow 5 minutes (or more) for color development.Spectrophotometric Measurement: Measure the color intensity with aspectrophotometer at a wavelength of 550 nm. Purified water may be used for ablank unless the water sample is cloudy. In that case, use a sample of cloudywateras a blank. Record the absorbance of the colored sample.

Waste DisposalAll solutions may be rinsed down the drain with water.

CalculationsFrom the concentration and the absorbance of the four standards, make a plotof absorbance as a function of concentration. Use the plot and the absorbance ofeach unknown solution to determine the concentration in mg/L nitrate ion (mgNO3-/L ) in that sample. Also, express the concentration in terms of mg/L of nitratenitrogen (mg N/L) in the sample.

ResultThe Nitrate nitrogen may be present in small amounts in fresh domestic wastewater…………


Determination of Calcium, Potassium and Sodium

Exp No: 8Date

Aim:To determine the calcium, potassium and sodium of the given water sample.

Reagents:

oral rehydration sachetNaCl standards: 10, 20, 40, and 80 mM

Technical note: In order to measure the change in potential difference across the ion-selective membrane as the ionic concentration changes, it is necessary to include in the circuit a reference electrode which acts as a half-cell from which to measure the relative deviationsProcedure:

NOTE: the bottom surfaces of the sodium ISE and reference electrode are very fragile. Do not let them drop on to the bottom of a beaker or bottle.

(a) Ensure that the multimeter (yellow box) and electrode amplifier (grey box) are connected properly with the black cable in the lowest socket (COM) and the red cable in the middle socket (V mA) and that the silver BNC connector from the electrode head is plugged into the back of the amplifier.

(b) With the electrodes immersed to a depth of about 3-4 cm in NaCl storage solution, switch on the multimeter to the 2000 mV position (4 clicks counterclockwise) and the amplifier to position I (down). Wait until the reading has stabilised (up to 5 min.) then remove the electrodes from the storage solution, wipe the bodies (but NOT the bottoms) with a tissue, transfer to a beaker of distilled water and rinse with swirling for about 30 sec.

(c) Remove the electrodes from the water, wipe as before, then transfer to the 10 mM NaCl standard. Swirl the solution for 15 sec to help the ISE membrane to equilibrate with the solution, then leave undisturbed for a further minute. Note the multimeter reading (this is millivolts, mV)

(the meter may fluctuate if you wave your hand over it so ensure that the environment is undisturbed when taking the reading).


(d) Remove, wipe and transfer the electrodes to the 20 mM standard and measure as before, waiting one minute before taking the reading.

(e) Repeat the procedure for the 40 mM and 80 mM standards.

[Na+] (mM) 10 20 40 80Log [Na+]

10Meter reading (mV)

5. Finally, take a reading in the same way from the undiluted redissolved sachet from Experiment A.

6. Transfer the electrodes back to distilled water and, if nobody else is going to use the system, switch off the multimeter and amplifier (position O).

7. Plot mV (y-axis) against log10 [Na+] (x-axis) and from this graph determine the apparent [Na+] in the redissolved sachet solution.

Meter reading for Log [Na+] fromNa Na+] in redissolved sachet (mM)

10undiluted sachet solution graph

Results:

a From the information provided on the sachet packaging, calculate the expected concentrations of Na+ and K+ ions in the solution you made.

[Na+] (mM) [K+] (mM)


(c) How do your own values for Na+ and K+ determined by flame photometry and for Na+ determined with the ISE compare to the expected values?

1. The class data for sodium determination only by both methods will be collected and tabulated on the blackboard in the class. Collect these data in the table below before you leave (12 sets maximum). Using a calculator, calculate the mean and standard deviation (S.D.) for the two data sets and compare these for accuracy and precision. What do you conclude

SL.NO 1 2 3 5 6 7 8 9 10 11 12

[Na+](flame)

[Na+] (ISE)

Sodium concentration (mean ± S.D, n =) by flame photometry = ……… (mM)

Sodium concentration (mean ± S.D, n =) by ISE= ……………… (mM)


Phosphate in wastewaterExp No: 8Date

Aim:

To determine the amount of phosphate (po4)present in waste water.

REAGENTS:

Stock Solution: This solution is only needed to make standard solution. Dissolve 219.5 mg of anhydrous KH2PO4 and dilute to 1,000 ml. This solution will be 50 ug P/ ml.

Standard Solution:Dilute 25 ml of stock solution to 500 ml. This will be 2.5 ug P/ml.The working standard is 2.5 ug/ml (2500 ppb) of phosphorus in phosphate (PO4-P). Use it to make a series of standards.

Standard Solutions

Volume (ul) used of the working standard, diluted to 25 ml.

Standard Conc.( ppb PO4-P )

ZERO BLANK100 10.0200 20.0400 40.0600 60.0800 80.0

5N Sulufuric Acid:Dilute 70 ml of conc. sulfuric acid to 500 ml.

Potassium antimonyl tartarate - K(SbO)C4H4O6.1/2 H2O:The bottle of the solid salt may be labeled as: Potassium antimoy(III) oxitartarate, or Antimony Potassium Tartarate.


Dissolve 1.3715 g in 400 ml H2O, Dilute to 500 ml. Store in glass bottle.

4% Ammonium Molybdate - (NH4)6 Mo7O24.4H2O:Dissolve 20 g in 500 ml. Stir for sometime (HARD TO DISSOLVE !!)Store in glass stoppered bottle.

Ascorbic Acid:Dissolve 1.76 g in 100 ml H2O. This solution is stable for ONE WEEK ONLY at 4 degrees C.

Combined Reagent:For 100 ml of the combined reagent add the following, IN ORDER:- 50 ml of 5N sulfuric acid. - 5 ml Potassium antimonyl tartarate. STIRR THOROUGHLY - 15 ml Ammonium Molybdate. STIRR THOROUGHLY- 30 ml Ascorbic acid. STIRR THOROUGHLY- Let the reagent cool down to room temperature.

This combined reagent is stable for 4 HOURS ONLY !!!

PROCEDURE:

- Take 25 ml sample in a 50-ml graduated tube- Add 4 ml combined reagent.- Cover the tube with parafilm and shake well.- Wait for blue color to develop. It needs 10-30 minutes time. - Measure absorbance on the Spectronic-21 at the wavelength 880 nm.

Results:

The amount of phosphate present in waste water…………


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