surveying-i laboratory manual · to determine the chlorine dose required for a given water sample....

Prepared by: Mr. Sandeep Siwach

Approved by: Dr. Arabinda Sharma

Civil Engineering Department

BRCM College of Engg & Technology

Bahal-127 028, Bhiwani

Haryana

2014 Environmental Engineering Manual


Prepared By: Sandeep Siwach 2 Approved By: Dr. Arabinda Sharma

LIST OF EXPERIMENTS

1. To determine the pH of the given water sample.

2. To determine the Turbidity of the given water sample

3. To determine the Acidity of the given water sample.

4. To determine the Alkalinity of the given water sample.

5. To determine the Hardness of the given water sample.

6. To determine the Chlorine dose required for a given water sample.

7. To determine the Total Solids, Suspended Solids and Total Dissolved Solids of a given

water sample

8. To determine Chloride Concentration in a given water sample.

9. To determine Sulphate Concentration in a given water sample.

10. To determine the Acidity of a given sewage sample.

11. To determine the Alkalinity of a given sewage sample.

12. To determine the Total Solids, Suspended Solids and Total Dissolved Solids of a given

sewage sampl.

13. To determine volatile and fixed solids in a sewage sample.

14. To determine the Oil and Grease in sewage sample.

15. To determine Chloride Concentration in a sewage sample.

16. To determine Sulphate Concentration in a sewage sample.

17. To determine B.O.D. of a given sewage sample.

18. To determine C.O.D. of a given sewage sample.

19. To determine T.O.C. of a given sewage sample.

20. To determine Fecal Count of a given sewage sample.

21. Microscopic studies of a sewage sample.

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EXPERIMENT NO:-1 OBJECT: To determine the pH of the given water sample.

THEORY:

The pH value of water (or of a solution) is defined as the log of reciprocal of hydrogen ions

present in that water. i.e.

pH = log10 1/H+

A pure water is infact, a balanced combination of positively charged hydrogen ions (H+) and

negatively charged hydroxyl ions (OH-): both long being equal .Moreover, the product of H

+ and

OH- has been found to be 10

-14 moles/litre.

Hence in a pure or a neutral water, the quantum of H+ and OH

- will each equal to √10

-14=10

-7 moles

/litre .The pH value of such a pure water will be equal to log10 1/10-7

= log 107 = 7.

If in a given water, H+ exceeds 10

-7 moles/litre (say it becomes 10

-6) then its pH value will become

less that 7 (say 6 in this case) and vice versa. It therefore, follows that if the pH value of the water is

found to be less than 7, it will become acidic in nature.

The pH value of water, thus, indicates the acidity or the alkalinity of water. The maximum acidity

will be at 0 values of pH and the maximum alkalinity at pH value of 14.

The pH is having a large scale importance in water supply system. Since it controls water as well as

sewage treatment processes. The pH value of raw water infact, must be taken into account. While

deciding the various treatment processes like coagulation, disinfection, water softening.etc.

The pH value also becomes important in corrosion control. Since lower pH values (acidic water)

may cause tuberculation and corrosion of pipes and treatment tanks etc. Higher pH values (alkaline

waters) may on the other hand produce incrustation. Sediment-deposit, difficulty in chlorination,

besides producing certain psychological effect on human system, if such alkaline water are

consumed.

The permissible pH values for public supplies may between 6.6 to 8.5.

REAGENTS

Distilled water

Rinsing bottle

pH buffer tablets (pH-0.4 and 9.2)

Beakers

Measuring cylinder(100ml)

Table –top pH-meter with pH electrode(calomel)

Thermometer

PROCEDURE

Buffer solution preparation -100ml distilled water was taken in a beaker using a 100ml

measuring cylinder. One pH buffer tablets of pH value 4 was dissolved in the water by stirring with

a glass rod. This resulting buffer solution will have value of 4. pH buffer solutions of values 9.2

were prepared in the similar manner.

pH meter calibration-the table-top pH meter, model LI-614, was first connected to the AC

power supply and kept for 2-3 minutes on stand by mode (FUNCTION knob in middle position i.e.

vertical position).temperature of the distilled water (in which electrode has been kept) was taken in




the mean time using a mercuric thermometer (temperature range = -10ºC to 110ºC). Temperature

knob was set at the temperature of distilled water. The function knob was moved towards position

(left side). The pH electrode was taken out of the distilled water, soaked with tissue paper, dipped in

the 4.0 pH buffer solution for and the reading was set (calibration) at 4.00 using the CALIBRATE

knob. Using litmus paper, a rough idea about pH of samples was taken. The next calibration using

SLOPE knob was done with buffer solution of either 4.0 or 9.2 pH respectively, depending on

whether acidic or basic samples are going to be analyzed. After calibration, pH readings of samples

were taken.

CALCULATION:

SAMPLE pH Temperature (°C)




EXPERIMENT NO:-2

OBJECT: To determine the Turbidity of the given water sample.

THEORY:

When light is passed through a sample having suspended particles, some of the light is

scattered by the particles. The scattering of the light is generally proportional to the turbidity. The

turbidity of sample is then measured from the amount of light scattered by the sample taking a

reference with standard turbidity suspension.

APPARATUS:

Nephelometric Turbidimeter

REAGENTS:

(i) Dissolve 1.0gm of Hydrazine sulphate and dilute to 100ml.

(ii) Dissolve 10gm Hexamethylene Tetramine and dilute to 100ml.

(iii) Mix 5ml of each of the above solution in a 100ml volumetric flask and allow to stand

for 24 hours at 25 ± 3ºC and dilute to 1000ml. This solution has a turbidity of 40

NTU.

(iv) This solution can be kept for about a month.

PROCEDURE:

(i) Switch on Nephelometric Turbidimeter and wait for few minutes till it warms up.

(ii) Set the instrument at 100 on the scale with a 40 NTU standard suspension. In case

every division on the scale will be equal to 0.4 NTU turbidity.

(iii) Shake thoroughly the sample and keep it for some time to eliminate the air bubbles.

(iv) Take sample in Nephelometer sample and put the sample in sample chamber and find

out the value on the scole.

(v) Dilute the sample with turbidity-free water and again read the turbidity.

OBSERVATION:

Sample Turbidity




EXPERIMENT NO:-3

OBJECT: To determine the Acidity of the given water sample.

THEORY:

Acidity is usually caused by the presence of free carbon dioxide, mineral acids such as

sulphuric and weakly dissociated acids. Iron and aluminium salts hydrolyze in water to release

mineral acidity. Surface waters and ground waters attain acidity from humic acids from industrial

wastes such as pickling liquors and from acid mine drainage. Generally the pH of most of the

samples is more than 7 and consequently carbon dioxide acidity is the only acidity present in them.

Samples contaminated with acidic wastes only will have a pH below 4.5 and contain both mineral

acidity and carbon dioxide acidity.

REAGENTS:

(i) Methyl orange indicator: Dissolve 50mg methyl orange powder in distilled water and dilute

to 100ml.

(ii) Phenolphthalein indicator solution: Dissolve 500mg phenolphthalein in 50ml ethyl or

isopropyl alcohol and add 50ml distilled water. Add 0.02 N sodium hydroxide solution drop wise

until a faint pink colour appears.

(iii) Sodium hydroxide solution, 0.02 N: Prepare sodium hydroxide solution by dissolving

40gm NaOH in distilled water and diluting to 1000ml. Standardize it against standard N-

sulphuric acid. Dilute appropriate volume of N-NaOH solution (about 20ml) to 1000ml to give a

0.02 N solution. 1.0ml of exactly 0.02 N-NaOH solution=1.0mg CaCO3.

PROCEDURE:

(i) Methyl Orange Acidity: Place 25ml of the sample in a 250ml of conical flask. Add 2 drops of

methyl orange indicator solution and titrate with 0.02 N NaOH solution (to pH 4.5) to faint orange

colour.

(ii) Total Acidity (using phenolphthalein) at room temperature: To a suitable aliquot of the

sample in a 250ml of conical flask add 3 drops phenolphthalein indicator. Titrate with 0.02 N NaOH

solutions to the appearance of faint pink colour (to pH 8.3).

(iii) Total Acidity (using phenolphthalein) at boiling temperature: Add 3 drops of

phenolphthalein indicator solution to 25ml of sample taken in a conical flask and heat to boiling for

about 2 minutes. Titrate while hot with 0.02 N-NaOH solutions to the permanent faint pink colour.

CALCULATIONS: Normality of sodium hydroxide solution is exactly 0.02N




AT ROOM TEMPATURE

SAMPLE INITIAL

READING

FINAL READING VOLUME USED OF

NaOH

AT BOILING TEMPERATURE

SAMPLE INITIAL

READING


NaOH




EXPERIMENT NO:-4

OBJECT: To determine the Alkalinity of the given water sample.

THEORY:

Alkalinity is the quantitative capacity aqueous media to react with hydrogen ions. The

alkalinity of natural and treated waters is normally due to the presence of bicarbonate, carbonate and

hydroxide compounds of calcium, magnesium, sodium and potassium. Borates and phosphates and

silicates also contribute to alkalinity. Some other ions not ordinarily found in natural water such as

arsenate, aluminate and certain organic anions in coloured waters could also increase the alkalinity.

Because of the relative abundance carbonate minerals and because of the ready availability of

carbon dioxide that enters into equilibria with them in water solution, most waters contain

bicarbonate and carbonates only. It is customary to calculate the hydroxide, carbonate and

bicarbonate alkalinities from the titre values with a standard acid. Each form of the alkalinity exists

separately or in combination. If there is phenolphthalein alkalinity it is due to hydroxide or

carbonate or both. If there is methyl orange alkalinity it is due to any one of the alkalinities or

hydroxides and carbonates together, or carbonate and bicarbonate together. It is to be stated that

hydroxide and bicarbonate alkalinities cannot co-exist.

Alkalinity is directly determined by titration with 0.02NH2SO4 using phenolphthalein and

methyl orange indicators.

Ca(OH)2 + H2SO4 ------CaSO4 + 2H2O

2CaCO3 + H2SO4 -------Ca(HCO3)2 + CaSO4

Ca(HCO3)2 + H2SO4 ------CaSO4 + 2CO2 + 2H2O

REAGENTS:

(i) Sulphuric acid 1N: Place 28ml conc. H2SO4 in a 1000ml volumetric flask and make up to

the mark with carbon dioxide free distilled water. Standardize it against 1N sodium carbonate

solution using methyl orange as the indicator. (End point is the appearance of faint orange

colour).

(ii) Sulphuric acid 0.02N: Dilute appropriate volume of 1N.H2SO4 (about 20ml) to 1000ml in a

volumetric flask with carbon di-oxide-free distilled water, to give a 0.02 N solution.

1.0ml exactly 0.02 N H2SO4 = 1.0mg CaCO3

(iii) Phenolphthalein indicator solution: Dissolve 500mg phenolphthalein in 50ml ethyl or

isopropyl alcohol and add 50ml distilled water. Add 0.02 N sodium hydroxide solution drop

wise until a faint pink colour appears.

PROCEDURE: (i) Phenolphthalein Alkalinity (P): Take 25ml of the sample in a 250ml of conical flask. Adjust

the volume to 50ml with distilled water. Add 4 drops of phenolphthalein indicator solution. If no

pink colour appears then titrate with 0.02N sulphuric acid (to pH 4.6) to light pink.

(ii) Methyl Orange Alkalinity (M): Add 3 drops of methyl orange indicator in a same solution.

Orange colour appears then titrates with 0.02N sulphuric acid (to pH 4.6) orange to pinkish

colour.




CALCULATIONS:

PHENOLPHTHALEIN ALKALINITY (P)

SAMPLE INITIAL

READING

FINAL READING VOLUME OF H2SO4

USED

METHYL ORANGE ALKALINITY (M)

SAMPLE INITIAL

READING

FINAL READING VOLUME OF H2SO4

USED

If the sulphuric acid used for titration is exactly 0.02 N, Phenolphthalein alkalinity (as CaCO3) mg/l

(P) Phenolphthalein Alkalinity as (CaCO3) mg/l =

(T) Total Alkalinity as (CaCO3) mg/l =

Calculation of three forms of alkalinity: The titre values obtained from phenolphthalein and total

alkalinity determinations are used to estimate the three forms of alkalinity as shown in the following

table:

Hydroxide- Carbonate- Bicarbonate-

alkalinity alkalinity alkalinity

as Ca CO3 as CaCO3 as CaCO3

P = 0 0 0 T

P < ½ T 0 2P T-2P

P = ½ T 0 2P 0

P > ½ T 2P-T 2(P-T)(T-P) 0

P = T T 0 0

Where P is phenolphthalein alkalinity and T is total alkalinity.

(It is assumed that the entire alkalinity is due to the presence of bicarbonate, carbonate and

hydroxide only and other ions contributing to alkalinity are absent).




EXPERIMENT NO:-5

OBJECT: To determine the Hardness of the given water sample.

EDTA TITRIMETRIC METHOD:

THEORY:

Hardness is deemed to be the capacity of water for reducing and destroying the lather of

soap. Hardness in water is due to the natural accumulation of salts from contact with soil geological

formations or it may enter from direct pollution by industrial effluents. Calcium and magnesium are

the principle cations causing hardness. Iron, aluminum, manganese, strontium and zinc also cause

hardness but to a relatively little extent or to negligible amount. The term “Total Hardness”

indicates the concentration of calcium and magnesium ions only. However, if present in significant

amounts the other metallic ions should also be included. The total hardness is expressed in terms of

calcium carbonate.

Calcium and magnesium ions react with EDTA to form soluble complexes and the

completion of reaction is indicated by the colour change of a suitable indicator such as Eriochrome

black T.

Ca2+

+ H2Y2-

--------- CaY2-

+ 2H+

(EDTA)

Mg2+

+ H2Y2-

--------- MgY2-

+ 2H+

MgD++ H2Y

2- --------- MgY

2- + HD

2-+ H

+

(wine red) (blue)

In this titration, calcium ions do not react with the indicator dye. Magnesium ions only react

and change the colour of the dye. Therefore, a small amount of complex metrically neutral

magnesium salt of EDTA is introduced to the titre through the addition of buffer to obtain end

point by colour change of the indicator.

Classification of Hardness:

Hardness has traditionally been classified into “Temporary Hardness” and “Permanent Hardness”.

The portion of hardness that disappears on prolonged boiling is referred as temporary hardness and

is mainly due to the bicarbonates of calcium and magnesium which are precipitated as normal

carbonates by the loss of CO2on heating. The hardness that remains after boiling is known as

permanent hardness and is due to the sulphates, chlorides and nitrates of calcium and magnesium.

However these terms are obsolete and the more precise terms are “carbonate hardness” and “non-

carbonate hardness”. The carbonate hardness is due to bicarbonates and carbonates of calcium and

magnesium while non-carbonate hardness is due to sulphates, chlorides and nitrates of calcium and

magnesium. When the hardness is numerically greater than the sum of the bicarbonate and

carbonate alkalinities, the amount equal to the alkalinity is carbonate hardness and the excess

amount is non-carbonate hardness. If the hardness is equal to or less than the sum of the bicarbonate

and carbonate alkalinities all of the hardness is carbonate hardness and there is no non-carbonate

hardness.




APPRATUS:

Burette with stand

Pipette

Two Conical Flasks

Measuring Cylinder

REAGENTS:

(i) Standard N/50 (0.02N) EDTA Solution: Dissolve 40gm of sodium salt of EDTA and

0.1gm MgCl2 in 800ml of distilled water. Standardize with CaCl2 solution.

(ii) Eriochrome Black T indicator: Dissolve 0.1gm of Eriochrome black T in 20ml of ethyl

alcohol.

(iii) Ammonia Buffer Solution: Dissolve 6.75gm of ammonium chloride in 75ml of liquid

ammonia and dilute to 100ml distilled water.

PROCEDURE:

(i) Take 25ml of water sample in a conical flask.

(ii) Add 1ml of Ammonia buffer to the flask.

(iii) Add a pinch of Eriochrome Black T indicator to the flask. Wine red colour will be

developed.

(iv) Titrate with standard EDTA solution (to be filled in burette) till the colour changes from

wine red to blue.

CALCULATIONS:

Normality of EDTA = 0.02N

TOTAL HARDNESS

PERMANENT HARDNESS

SAMPLE INITIAL

READING

FINAL

READING

VOLUME

USED OF

EDTA

SAMPLE INITIAL

READING

FINAL

READING

VOLUME

USED OF

EDTA




CaCO3

(Unboiled sample)

Permanent CaCO3

(Boiled sample)

Temporary Hardness = -




EXPERIMENT NO:-6

OBJECT: To determine the Chlorine dose required for a given water sample.

THEORY:

The chlorine demand of a water sample will be equal to the chlorine required to be added to the

water, as to just make the free chlorine available in water sample after a contact period of 30

minutes.

REAGENTS:

(i) N/35.5 Chlorine Water

(ii) Potassium Iodide

(iii) Concentrated Hydrochloric acid (HCl) 1+1: 250ml concentrated hydrochloric acid

and dilute to 250ml with distilled water and cool.

(iv) Starch Solution: Dissolve 1gm starch in a little water. Stir it with a glass rod to make it

as a thin paste. Pour this paste in about 100ml boiling distilled water and boil for 2 minutes

and cool.

PROCEDURE:

(i) Place 200ml of the well mixed water sample in each of 4 number 300ml bottles.

(ii) Add 0.5ml of standard N/35.5 chlorine water to the first bottles 1.0ml to second 1.5ml to

the third and 2.0ml to the fourth bottles.

(iii) Shake each bottles gently allow to stand for 30 minutes of contact period.

(iv) Add a pinch of potassium iodide and 1ml of conc. HCl acid to 4 each bottles.

(v) Add 1ml of starch solution of each bottles.

(vi) Identify that bottle (out of four bottles) which contains the least blue colour (rather just

appear blue colours). The chlorine water added in this particular bottle may be recorded.

CALCULATION:

Sample Volume = 200ml

Normality of Chlorine (N) = N/35.5

Chlorine(Cl-)=




EXPERIMENT NO:-7

OBJECT: To determine the Total Solids, Suspended Solids and Total Dissolved Solids of a

given water sample

THEORY:

The total amount of solids (TS) includes the suspended solids (SS) as well as the dissolved

solids. The total solids in a waste water sample can be determined by evaporating the sample and

weighing the dry residue left. The suspended solids can be found by filtering the sample weighing

the dry residue left on the filter paper. The difference between total solids and suspended solids will

represent nothing but the dissolved solids.

The dissolved solids, which usually predominate in waters, consist mainly of inorganic salts,

small amount of organic matter and dissolved gases. The suspended solids contain much of the

organic matter and any increase thereof tends to increase the degree of pollution in water.

The amount of total solids (TS) in given water up to 500mg/l generally makes it suitable for

domestic uses. Waters with higher T.S. contents up to about 1000mg/l, may also be acceptable,

although may cause some psychological effects on some human beings, consuming such a water.

High concentrations of dissolved solids in waters when used in boilers may lead to boiler troubles

lead priming and foaming.

APPARATUS:

Beaker

Measuring Cylinder

Heating Plate

Weighing Machine with weights

Filter paper

Funnel

Oven

Petriplate

PROCEDURE:

(i) Weigh the Petriplate (clean and dry) and record its mass as A gm.

(ii) Fill 50ml of water sample in the petriplate.

(iii) Place the petriplate on heating plate and evaporate the sample to dryness.

(iv) After cooling the beaker, record the mass of the petriplate with dry residue in gm. Let it

be B gm.

(v) Take another 50ml of sample and given the standard filter paper.

(vi) Record the mass of the filter paper. Let it be C gm.

(vii) Filter the sample through the filter paper in a funnel.

(viii) Place the filter paper with residue in an oven and evaporate it to the dryness.

(ix) Record the mass of the filter paper and residue as D gm.




CALCULATION:

Total Solids

Sample Volume = 50 ml

Mass of empty petriplate (A) = ….. gm

Mass of empty petriplate + Residue = ….. gm

(Y) Concentration = (B-A) = 44.63-44.61 = ….. gm

Total Solids (mg/l) =

Suspended Solids

Mass of filter paper (C) = ….. gm

Mass of filter paper + Residue (D) = …. gm

(X) Concentration = (D-C) = 0.90-0.89 = …. gm


Total Dissolved Solids = (Y-X) = Total Solid-Suspended Solid




EXPERIMENT NO:-8

OBJECT: To determine Chloride Concentration in a given water sample.

SILVER NITRATE METHOD:

THEORY:

Chloride is the common anion found in water and sewage. The concentration of chloride in

natural waters varies from a few milligrams to several thousand milligrams per litre. Higher

concentrations of chloride may be due to the contamination by sea water, brines, sewages or

industrial effluents such as those from paper works, galvanizing plants, water softening plants and

petroleum refineries.

Silver nitrate reacts with chloride ions to form silver chloride. The completion of reaction is

indicated by the red colour produced by the reaction of silver nitrate with potassium chromate

solution which is added as an indicator.

AgNO3 + Cl -----------AgCl + 2KNO3

2AgNO3 + K2CrO4 -----------Ag2CrO4 + 2KNO3

APPARATUS:

Burette with stand

Pipette

Measuring Cylinder (100ml)

Two Conical Flasks

N/35.5 AgNO3Solution (Silver Nitrate Solution)

REAGENTS:

Use chloride –free distilled water for the preparation of all reagents :

(i) Standard Silver Nitrate Titrant, N/35.5 (0.0282N): Dissolve 4.791gm silver nitrate,

AgNO3 in distilled water and make up to 1000ml in a volumetric flask. Standardize it against

0.0282N sodium chloride solutions

1.0ml of exactly 0.0282 N AgNO3 = 1.0mg Cl

(ii) Potassium Chromate Indicator Solution: Dissolve 25gm potassium chromate (K2CrO4)

in distilled water. Add silver nitrate solution drop wise until a slight red precipitate is formed. Allow

to stand for 12 hours. Filter and dilute the filterate to 500ml.

PROCEDURE:

(i) Take 25ml of sample in a conical flask.

(ii) Place the same quantity of chloride free distilled water in another flask, to serve as a blank.

(iii) Add to both the flasks. 10 drops of potassium chromate indicator each.

(iv) Titrate the sample as well the distilled water (Blank) in both the flasks with N/35.5 Silver

Nitrate Solution.

(v) Note the amount of titrant used till yellow colour in the flask is turned into reddish colour.




CALCULATION:

Equivalent Weight of Chloride = 35.45

Normality of AgNO3 =N/35.45

Chloride Conc. CaCO3 =

Sample INITIAL

READING


AgNO3

Blank (Dist.Water)

Sample INITIAL

READING


AgNO3

Sewage Sample




EXPERIMENT NO:-9

OBJECT: To determine Sulphate Concentration in a given water sample.

THEORY:

Sulphates occur naturally in water as result of leachings from gypsum and other common

minerals. In addition, sulphate may be added to water systems in several treatment processes. The

sulphate content of municipal water supplies is usually increased during clarification by alum.

Sulphates contribute to the total solids content and the determination of sulphate is sometimes used

to control the washing of blades to free them from deposits.

Sulphates is precipitated as barium sulphate in the presence of hydrochloric acid. The

precipitated barium sulphate is filtered, dried, ignited and weighed as BaSO4.

BaCl2 + SO42-

-------- BaSO4 + 2Cl-

REAGENTS:

(i) Methyl Red Indicator: Dissolve 5.0gm methyl orange in 1.0 litre of distilled water.

(ii) Hydrochloric Acid, 1 + 1.

(iii) Barium Chloride 5%, Dissolve 25gm barium chloride dihydrate BaCl2.2H2O in 500ml

distilled water. (If any turbidity appears on standing reject the solution).

PROCEDURE:

(i) Measure in to a 100ml beaker appropriate volume of clear sample containing 8 to 60mg

sulphate (Usually 50ml). (If the sulphate content of the sample is very low take higher volumes

of the sample and evaporate on a water bath to 50ml).

(ii) Adjust the pH of the sample to 4.5 - 5.0 with HCl using methyl red indicator (to orange

colour). Then add additional 2ml, HCl. The samples are acidified to eliminate the precipitation

of BaCO3 which might occur in highly alkaline waters maintained near the boiling temperature.

(If the sample is already digested with conc. HCl to remove suspended impurities).

(iii) Boil the solution for about one minute and add 10ml hot barium-chloride solution slowly

from a pipette with constant stirring.

(iv) Keep the beaker put on a stand to cool them.

(v) Weigh the filter paper and then pass this sample through filter paper, digest the precipitate at

103-1080C for atleast 30 minutes.

(vi) Dry the filter paper and weigh.

CALCULATION:

mg/l sulphate as SO42-

=




EXPERIMENT NO:-10

OBJECT: To determine the Acidity of a given sewage sample.

THEORY:

Acidity is usually caused by the presence of free carbon dioxide, mineral acids such as

sulphuric and weakly dissociated acids. Iron and aluminium salts hydrolyze in water to release

mineral acidity. Surface waters and ground waters attain acidity from humic acids from industrial

wastes such as pickling liquors and from acid mine drainage. Generally the pH of most of the

samples is more than 7 and consequently carbon dioxide acidity is the only acidity present in them.

Samples contaminated with acidic wastes only will have a pH below 4.5 and contain both mineral

acidity and carbon dioxide acidity.

REAGENTS:

(i) Methyl orange indicator: Dissolve 50mg methyl orange powder in distilled water and dilute

to 100ml.

(ii) Phenolphthalein indicator solution: Dissolve 500mg phenolphthalein in 50ml ethyl or

isopropyl alcohol and add 50ml distilled water. Add 0.02 N sodium hydroxide solution drop wise

until a faint pink colour appears.

(iii) Sodium hydroxide solution, 0.02 N: Prepare sodium hydroxide solution by dissolving

40gm NaOH in distilled water and diluting to 1000ml. Standardize it against standard N-

sulphuric acid. Dilute appropriate volume of N-NaOH solution (about 20ml) to 1000ml to give a

0.02 N solution. 1.0ml of exactly 0.02 N-NaOH solution=1.0mg CaCO3.

PROCEDURE:

(i) Methyl Orange Acidity: Place 25ml of the sample in a 250ml of conical flask. Add 2 drops of

methyl orange indicator solution and titrate with 0.02 N NaOH solution (to pH 4.5) to faint orange

colour.

(ii) Total Acidity (using phenolphthalein) at room temperature: To a suitable aliquot of the

sample in a 250ml of conical flask add 3 drops phenolphthalein indicator. Titrate with 0.02 N NaOH

solutions to the appearance of faint pink colour (to pH 8.3).

(iii) Total Acidity (using phenolphthalein) at boiling temperature: Add 3 drops of

phenolphthalein indicator solution to 25ml of sample taken in a conical flask and heat to boiling for

about 2 minutes. Titrate while hot with 0.02 N-NaOH solutions to the permanent faint pink colour.

CALCULATIONS: Normality of sodium hydroxide solution is exactly 0.02N




AT ROOM TEMPATURE

SAMPLE INITIAL

READING

FINAL READING VOLUME USED

OF NaOH

AT BOILING TEMPERATURE

SAMPLE INITIAL

READING


NaOH




EXPERIMENT NO:-11

OBJECT: To determine the Alkalinity of a given sewage sample.

THEORY:

Alkalinity is the quantitative capacity aqueous media to react with hydrogen ions. The

alkalinity of natural and treated waters is normally due to the presence of bicarbonate, carbonate and

hydroxide compounds of calcium, magnesium, sodium and potassium. Borates and phosphates and

silicates also contribute to alkalinity. Some other ions not ordinarily found in natural water such as

arsenate, aluminate and certain organic anions in coloured waters could also increase the alkalinity.

Because of the relative abundance carbonate minerals and because of the ready availability of

carbon dioxide that enters into equilibria with them in water solution, most waters contain

bicarbonate and carbonates only. It is customary to calculate the hydroxide, carbonate and

bicarbonate alkalinities from the titre values with a standard acid. Each form of the alkalinity exists

separately or in combination. If there is phenolphthalein alkalinity it is due to hydroxide or

carbonate or both. If there is methyl orange alkalinity it is due to any one of the alkalinities or

hydroxides and carbonates together, or carbonate and bicarbonate together. It is to be stated that

hydroxide and bicarbonate alkalinities cannot co-exist.

Alkalinity is directly determined by titration with 0.02NH2SO4 using phenolphthalein and

methyl orange indicators.

Ca(OH)2 + H2SO4 ------CaSO4 + 2H2O

2CaCO3 + H2SO4 -------Ca(HCO3)2 + CaSO4

Ca(HCO3)2 + H2SO4 ------CaSO4 + 2CO2 + 2H2O

REAGENTS:

(i) Sulphuric acid 1N: Place 28ml conc. H2SO4 in a 1000ml volumetric flask and make up to

the mark with carbon dioxide free distilled water. Standardize it against 1N sodium carbonate

solution using methyl orange as the indicator. (End point is the appearance of faint orange

colour).

(ii) Sulphuric acid 0.02N: Dilute appropriate volume of 1N.H2SO4 (about 20ml) to 1000ml in a

volumetric flask with carbon di-oxide-free distilled water, to give a 0.02 N solution.

1.0ml exactly 0.02 N H2SO4 = 1.0mg CaCO3

(iii) Phenolphthalein indicator solution: Dissolve 500mg phenolphthalein in 50ml ethyl or

isopropyl alcohol and

add 50ml distilled water. Add 0.02 N sodium hydroxide solution drop wise until a faint pink

colour appears.

PROCEDURE: (i) Phenolphthalein Alkalinity (P): Take 25ml of the sample in a 250ml of conical flask. Adjust

the volume to 50ml with distilled water. Add 4 drops of phenolphthalein indicator solution. If no

pink colour appears then titrate with 0.02N sulphuric acid (to pH 4.6) to light pink.

(ii) Methyl Orange Alkalinity (M): Add 3 drops of methyl orange indicator in a same solution.

Orange colour appears then titrates with 0.02N sulphuric acid (to pH 4.6) orange to pinkish

colour.




CALCULATIONS:

PHENOLPHTHALEIN ALKALINITY (P)

SAMPLE INITIAL

READING

FINAL READING VOLUME OF

H2SO4 USED

METHYL ORANGE ALKALINITY (M)

SAMPLE INITIAL

READING

FINAL READING VOLUME OF

H2SO4 USED

If the sulphuric acid used for titration is exactly 0.02 N, Phenolphthalein alkalinity (as CaCO3)

mg/l

(P) Phenolphthalein Alkalinity as (CaCO3) mg/l =

(T) Total Alkalinity as (CaCO3) mg/l =




Calculation of three forms of alkalinity: The titre values obtained from phenolphthalein and

total alkalinity determinations are used to estimate the three forms of alkalinity as shown in the

following table:

Hydroxide- Carbonate- Bicarbonate-

alkalinity alkalinity alkalinity

as Ca CO3 as CaCO3 as CaCO3

P = 0 0 0 T

P < ½ T 0 2P T-2P

P = ½ T 0 2P 0

P > ½ T 2P-T 2(P-T)(T-P) 0

P = T T 0 0

Where P is phenolphthalein alkalinity and T is total alkalinity.

(It is assumed that the entire alkalinity is due to the presence of bicarbonate, carbonate and

hydroxide only and other ions contributing to alkalinity are absent).




EXPERIMENT NO:-12

OBJECT: To determine the Total Solids, Suspended Solids and Total Dissolved Solids of a

given sewage sample

THEORY:

The total amount of solids (TS) includes the suspended solids (SS) as well as the

dissolved solids. The total solids in a waste water sample can be determined by evaporating the

sample and weighing the dry residue left. The suspended solids can be found by filtering the sample

weighing the dry residue left on the filter paper. The difference between total solids and suspended

solids will represent nothing but the dissolved solids.

The dissolved solids, which usually predominate in waters, consist mainly of inorganic salts,

small amount of organic matter and dissolved gases. The suspended solids contain much of the

organic matter and any increase thereof tends to increase the degree of pollution in water.

The amount of total solids (TS) in given water up to 500mg/l generally makes it suitable for

domestic uses. Waters with higher T.S. contents up to about 1000mg/l, may also be acceptable,

although may cause some psychological effects on some human beings, consuming such a water.

High concentrations of dissolved solids in waters when used in boilers may lead to boiler troubles

lead priming and foaming.

APPARATUS:

Beaker

Measuring Cylinder

Heating Plate

Weighing Machine with weights

Filter paper

Funnel

Oven

Petriplate

PROCEDURE:

(i) Weigh the Petriplate (clean and dry) and record its mass as A gm.

(ii) Fill 50ml of water sample in the petriplate.

(iii) Place the petriplate on heating plate and evaporate the sample to dryness.

(iv) After cooling the beaker, record the mass of the petriplate with dry residue in gm. Let it

be B gm.

(v) Take another 50ml of sample and given the standard filter paper.

(vi) Record the mass of the filter paper. Let it be C gm.

(vii) Filter the sample through the filter paper in a funnel.

(viii) Place the filter paper with residue in an oven and evaporate it to the dryness.

(ix) Record the mass of the filter paper and residue as D gm.




CALCULATION:

Total Solids

Sample Volume = 50 ml

Mass of empty petriplate (A) = ….. gm

Mass of empty petriplate + Residue = ….. gm

(Y) Concentration = (B-A) = 44.63-44.61 = ….. gm


Suspended Solids

Mass of filter paper (C) = ….. gm

Mass of filter paper + Residue (D) = …. gm

(X) Concentration = (D-C) = 0.90-0.89 = …. gm


Total Dissolved Solids = (Y-X) = Total Solid-Suspended Solid




EXPERIMENT NO:-12

OBJECT: To determine volatile and fixed solids in a sewage sample.

THEORY:

The methods are gravimetric. Great care must be taken to obtain a representative sample. The

quantity of sample to be taken depends on the amount of suspended matter.

Water 100 ml to 500ml

Sewage 50ml to 100ml

Waste effluent 50ml to 100ml

APPARATUS:

Table, porcelain dish, measuring cylinder, heater, weighing machine with weights, beaker,

filter paper funnel, oven, etc.

PROCEDURE:

(a) Total solids

Place the required quantity of the sample in a dry constant weight dish or crucible.

Evaporate to dryness in an oven at 103° - 105°C and dry to a constant weight. Cool

the dish in a dessicator. Weigh and note the increase in weight.

Total solids mg/l = (weight of crucible with residue – weight of empty crucible) mg X 1000/ml

sample

(b) Total solids: Volatile and fixed

Ignite the residue obtained in (a) at 600°C in a muffle furnace (15-20 min.) cool and weigh.

Total volatile solids mg/l = [(weight of crucible with total residue – Weight of empty crucible) –

(Weight of crucible with residue heated to 600°C) mg X 100] ÷ [ml sample]

OBSERVATIONS:

Sample details

Source Volume

Type of Solids Weight of

empty

Beaker

Weight of

with

Residue

Weight of

mg/l

Residue

Total solids

Volatile solids

Fixed solids




EXPERIMENT NO:-14

OBJECT: To determine the Oil and Grease in sewage sample.

THEORY:

Fats and oil are mainly contributed from kitchen wastes. Grease and oils are also discharged

from industries like garages, workshops factories etc. Such matters float on the top of sedimentation

tanks, often choke pipes in winter and clog filters.

APPARATUS:

Floatation Funnel

Stand

Beaker

Stirrer

Heating Plate

REAGENTS:

(i) Hydrochloric Acid (HCL)

(ii) Ether

PROCEDURE:

(i) Place 100ml waste water in a conical flask.

(ii) Add 1ml HCL to it.

(iii) Transfer the sample into floatation funnel.

(iv) Keep on stirring for 15 minutes.

(v) Open the stop valve and remove the water.

(vi) Add 10ml of ether into the funnel and mix the solution till oil and grease material get

dissolved in it.

(vii) Evaporate the solution.

(viii) Measure the weight of residue left behind.




EXPERIMENT NO:-15

OBJECT: To determine Chloride Concentration in a sewage sample.

SILVER NITRATE METHOD:

THEORY:

Chloride is the common anion found in water and sewage. The concentration of chloride in

natural waters varies from a few milligrams to several thousand milligrams per litre. Higher

concentrations of chloride may be due to the contamination by sea water, brines, sewages or

industrial effluents such as those from paper works, galvanizing plants, water softening plants and

petroleum refineries.

Silver nitrate reacts with chloride ions to form silver chloride. The completion of reaction is

indicated by the red colour produced by the reaction of silver nitrate with potassium chromate

solution which is added as an indicator.

AgNO3 + Cl -----------AgCl + 2KNO3

2AgNO3 + K2CrO4 -----------Ag2CrO4 + 2KNO3

APPARATUS:

Burette with stand

Pipette

Measuring Cylinder (100ml)

Two Conical Flasks

N/35.5 AgNO3Solution (Silver Nitrate Solution)

REAGENTS:

Use chloride –free distilled water for the preparation of all reagents :

(i) Standard Silver Nitrate Titrant, N/35.5 (0.0282N): Dissolve 4.791gm silver nitrate,

AgNO3 in distilled water and make up to 1000ml in a volumetric flask. Standardize it against

0.0282N sodium chloride solutions

1.0ml of exactly 0.0282 N AgNO3 = 1.0mg Cl

(ii) Potassium Chromate Indicator Solution: Dissolve 25gm potassium chromate (K2CrO4)

in distilled water. Add silver nitrate solution drop wise until a slight red precipitate is formed. Allow

to stand for 12 hours. Filter and dilute the filterate to 500ml.

PROCEDURE: (i) Take 25ml of sample in a conical flask.

(ii) Place the same quantity of chloride free distilled water in another flask, to serve as a

blank.

(iii) Add to both the flasks. 10 drops of potassium chromate indicator each.




(iv) Titrate the sample as well the distilled water (Blank) in both the flasks with N/35.5 Silver

Nitrate Solution.

(v) Note the amount of titrant used till yellow colour in the flask is turned into reddish colour.

CALCULATION:

Equivalent Weight of Chloride = 35.45

Normality of AgNO3 =N/35.45

Chloride Conc. CaCO3 =

Sample INITIAL

READING


AgNO3

Blank (Dist.Water)

Sample INITIAL

READING


AgNO3

Sewage Sample

\




EXPERIMENT NO:-16

OBJECT: To determine Sulphate Concentration in a sewage sample.

THEORY:

Sulphates occur naturally in water as result of leachings from gypsum and other common

minerals. In addition, sulphate may be added to water systems in several treatment processes. The

sulphate content of municipal water supplies is usually increased during clarification by alum.

Sulphates contribute to the total solids content and the determination of sulphate is sometimes used

to control the washing of blades to free them from deposits.

Sulphates is precipitated as barium sulphate in the presence of hydrochloric acid. The

precipitated barium sulphate is filtered, dried, ignited and weighed as BaSO4.

BaCl2 + SO42-

-------- BaSO4 + 2Cl-

REAGENTS:

(i) Methyl Red Indicator: Dissolve 5.0gm methyl orange in 1.0 litre of distilled water.

(ii) Hydrochloric Acid, 1 + 1.

(iii) Barium Chloride 5%, Dissolve 25gm barium chloride dihydrate BaCl2.2H2O in 500ml

distilled water. (If any turbidity appears on standing reject the solution).

PROCEDURE:

(i) Measure in to a 100ml beaker appropriate volume of clear sample containing 8 to 60mg

sulphate (Usually 50ml). (If the sulphate content of the sample is very low take higher volumes

of the sample and evaporate on a water bath to 50ml).

(ii) Adjust the pH of the sample to 4.5 - 5.0 with HCl using methyl red indicator (to orange

colour). Then add additional 2ml, HCl. The samples are acidified to eliminate the precipitation

of BaCO3 which might occur in highly alkaline waters maintained near the boiling temperature.

(If the sample is already digested with conc. HCl to remove suspended impurities).

(iii) Boil the solution for about one minute and add 10ml hot barium-chloride solution slowly

from a pipette with constant stirring.

(iv) Keep the beaker put on a stand to cool them.

(v) Weigh the filter paper and then pass this sample through filter paper, digest the precipitate at

103-1080C for atleast 30 minutes.

(vi) Dry the filter paper and weigh.

CALCULATION:

mg/l sulphate as SO42-

=




EXPERIMENT NO:-17

OBJECT: To determine B.O.D. of a given sewage sample.

THEORY:

The biochemical oxygen demand (BOD) is the amount of oxygen required by bacteria while

stabilizing decomposable organic matter under aeroble conditions. The quantity of oxygen required

may be taken as a measure of its content of decomposable organic matter. The rate of BOD exertion

is governed by the characteristics of sewage. Its decomposable organic content, bacterial population

and temperature. The progressive BOD exertion takes place in two stages.

(a) Carbonaceous, (b) Nitrification

It has been observed the large percentage of total BOD is exerted in 5 days at 20°C. The value of 5

days at 20°C is to a reasonable extent comparable to 4 days at 30°C and 3 days at 35°C.

Y = L (1 – 10-kt

)

Y = BOD at any time

L = Ultimate BOD

k = reaction rate

t = time

REAGENTS:

(i) Phosphate buffer

(ii) Magnesium sulphate solution

(iii) Calcium chloride solution

(iv) Ferric chloride solution

(v) Manganous sulphate solution

(vi) Alkaline Potassium iodide solution

(vii) N/40 sodium thiosulphate solution

(viii) Conc. sulphuric acid

(ix) Starch indicator

BOD MEASURABLE WITH VARIOUS DILUTIONS

Range of BOD % mixture

200-700 1.00

100-350 2.00

40-140 5.00

20-70 10.00

10-35 20.00

4-14 50.00

PROCEDURE:

Prepare dilution water by adding 1.0ml each of phosphate buffer solution, magnesium sulphate

solution, calcium chloride and ferric chloride solution to 1.0litre of distilled water. Add 2.0ml

settled sewage and aerate. Determine the exact capacity of three BOD capacities of three BOD

bottles. Find out the D.O. of undiluted sample as in 4.8 and designate as DO.

Prepare the desired percent mixture by adding sample in dilution water. Fill up one bottle with the

mixture and the other one with dilution water (blank). Incubate at a fixed temperature for a definite

time (20°C, 5 days). Find out DO in both the bottles after incubation and designate.




Mixture as (DO₁)

Blank (DOь)

CALCULATIONS:

BOD mg/l = [(DOь - DO₁) 100%) – (DOь - DOѕ)]

OBSERVATIONS:

Sample details

Source

% mixture DOѕ DOь DO₁ BOD mg/l




EXPERIMENT NO:-18

OBJECT: To determine C.O.D. of a given sewage sample.

THEORY:

Chemical oxygen demand test is widely used for measuring the pollutional strength of waste

waters. All organic compounds with a few exceptions can be oxidized to carbon dioxide and water

by the action of strong oxidizing agents regardless of biological assimilability of assimilability of

the substances.

REAGENTS:

(i) Standard potassium dichromate 0.25 N

(ii) Sulphuric acid 9with 1gm of silver sulphate in every 75ml acid)

(iii) Ferrion indicator solution

(iv) Standard ferrous ammonium sulphate solution

STANDARDIZATION PROCEDURE:

Dilute 25ml standard potassium dichromate solution to about 250ml with distilled water.

Add 20ml cone. Sulphuric acid, Titrate with ferrous ammonium sulphate solution using ferroin

indicator to red end point.

Normality of FeSO₄ (NH₄)₂ SO₄ =

PROCEDURE:

(a) Place 50ml or fraction diluted to 100ml of sample with distilled water in hard glass bottle

and add 25ml standard potassium dichromate solution. Carefully add 75ml cone. H2SO4

mixing after each addition. Digest the mixture in pressure cooker or autoclave for 30 min.

(b) Repeat the procedure with 100ml distilled water and reagents as in (a).

(c) Transfer the contents to a 500ml conical flask. Dilute the mixture to about 350ml. Titrate the

excess dichromate with standard ferrous ammonium sulphate using ferroin indicator. The

end point is red. Designate the titration value for sample (a) as B and for distilled (b) as A.

CALCULATIONS:

COD mg/l = (A-B) C X 8 X 1000/ml sample

Where A = ml FeSO₄ (NH₄)₂ SO₄ used for bank

B = ml FeSO₄ (NH₄)₂ SO₄ used for sample

C = ml FeSO₄ (NH₄)₂ SO₄ solution determined above.

OBSERVATIONS:

Sample details

Source Volume

Normality

of K2Cr₂O₇ Amount of

K2Cr₂O₇ Added

Normality of

FeSO₄ (NH₄)₂ SO₄

ml of FeSO₄ (NH₄)₂ SO₄

Used

COD mg/l




EXPERIMENT NO:-19

OBJECT: To determine T.O.C. of a given sewage sample.

THEORY:

T.O.C. test is applicable to small amount of organic matter. The organic matter when mixed

with acid produces CO2 equivalent to its amount.

APPARATUS:

Carbonaceous Analyzer

Furnace

PROCEDURE:

The TOC test consists of acidification of the waste water sample to convert inorganic carbon

to CO2 which is then stripped. The sample is then injected into a high temperature furnace where it

is oxidized in the presence of a catalyst. The CO2 that is produced is quantitatively measured by

means of an infrared analyzer and converted instrumentally to original organic carbon content. The

error due to the presence of inorganic carbon can be eliminated by acidification and aeration of the

sample prior to the analysis.

CALCULATION:

%C = [(B-S)* M of FAS* 12* 100]/ gram of sludge* 4000

B = ml of FAS used for titrating blank

S = ml of FAS used for titrating sample

12/4000 = milliequivalent weight of C in grams

To convert easily oxidizable organic C to total organic carbon, divide by 0.77 or multiply by 1.3.




EXPERIMENT NO:-20

OBJECT: To determine Fecal Count of a given sewage sample.

THEORY:

The method1.2

is similar to the fecal coliform membrane filter procedure but uses a different medium

and incubation temperature to yield results in 7 h that generally are comparable to those obtained by

the standard fecal coliform method.

APPARATUS:

Incubator

Filter Paper

MEDIUM:

M-7 h FC agar: This medium may not be available in dehydrated form and may require

preparation for the basic ingredients.

Proteose peptone No.3 or polypeptone…………………………. 5.0 g

Yeast extract……………………………………………………. 3.0 g

Lactose………………………………………………………….. 10.0 g

D-Mannitol……………………………………………………… 5.0 g

Sodium chloride, NaCl………………………………………….. 7.5 g

Sodium lauryl sulfate…………………………………………… 0.2 g

Sodium desoxycholate………………………………………….. 0.1 g

Bromeresol purple……………………………………………….. 0.35 g

Phenol red……………………………………………………….. 0.3 g

Agar………………………………………………………………15.0 g

Reagent-grade water……………………………………………… 1 L

Heat in boiling water bath. After ingredients are dissolved heat additional 5 min. cool to 55

to 60ºC and adjust the pH to 7.3 ± 0.1 with 0.1 N NaOH (0.35mL/L usually required). Cool to about

45ºC and dispense in 4 to 5ml quantities to Petri plates with tight-fitting covers. Store at 2 to 10ºC.

Discard after 30 d.

PROCEDURE:

Filter an appropriate sample volume through a membrane filter, place filter on the surface of

a plate containing M-7 b. Fecal coliforms colonies are yellow (indicative of lactose fermentation).




EXPERIMENT NO:-21 OBJECT: Microscopic studies of a sewage sample.

THEORY:

It frequently becomes desirable to examine Sewage of organisms higher in the scale of the

than bacteria. i.e., Protozoa, relatively small metazoa, Algae and the like. Certain of these organisms

impart very undesirable odors, to Sewage. The numbers present are usually few; however, it is

necessary to use a method by which those present in a relatively large volume of Sewage can be

concentrated into a small volume before an accurate tabulation can be made. This could be achieved

by centrifuge. Sedgwick Rafter funnel, plankton net.

More frequently the organisms are counted and the actual number reported in terms of

standard units or cubic standard units. A standard unit is the area of a visible surface of 400 square

microns. A cubic standard unit is a volume of 8000cubic microns.

APPARATUS: Microscope

PROCEDURE:

(i) Arrange a Sedgwick-rafter filter funnel. Filter through it a known volume of the Sewage

under examination (9500 to 1000ml) refiltering the first 200ml. Concentrate the material removed

by the filter into 20ml by washing the sand from the filter in this volume of Sewage and decanting

the liquid.

(ii) Thoroughly mix the organisms by blowing air into the liquid through a pipette. Remove

1ml and place it in a Sedgwick Rafter counting cell.

(iii) With the aid of a whipple ocular micrometer, examine and record units. The

examination and enumeration of organisms consists of two steps, the survey and the total count. The

microscope tube length, objective and so on, is adjusted so that the area covered by the ruled square

of the ocular micrometer is exactly one square millimeter and since the depth is one millimeter, the

volume by the ruled square is one cubic millimeter.

OBSERVATIONS & CALCULATIONS: In the survey the entire cell is examined for large organisms and the results recorded. In the

total count the organisms within the ruled area are counted. The cell is then moved and another area

counted and the process is repeated until ten representative areas are counted. The average then

gives the numbers of units in one cubic millimeter. Since there are some variations in the specific

gravity of water organisms, care should be exercised to change the focus of the microscope in order

that both the upper and the lower strata are examined. From the data thus

obtained the number of organisms per ml in the original sample is calculated by the formula

N = w/f (S/V = 1000t/n)

Where

W = ml concentrate

f = ml filtered

S = number of organisms found in the survey

V = volume in ml of counting cell

T = total number of organisms found in the total count of all squares

N = number of squares.


surveying-i laboratory manual · to determine the chlorine dose required for a given water sample....

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