CHAPTER CHAPTER CHAPTER CHAPTER –––– 2222

Material And Methods

The study was carried out based on primary data collection, which involved a

survey on the Physico parameters in Kathalal regions followed by detailed water

quality analysis of these regions . samples were collected in pre cleaned 2.5litter

polyethylene bottles. The sampling, preservation and analysis were done as per

APHA (1998). The Instruments were calibrated before each of measurement and

chemicals used were of GR grade .In addition to fluoride, other water quality

parameters such as pH, total dissolved solids, chloride, bicarbonate, calcium,

magnesium, total hardness, calcium parameters such as pH, total dissolved solids,

chloride, bicarbonate, calcium, magnesium, total hardness, calcium hardness were

also analyzed. Since no samples contained interfering radicals higher than the

prescribed limit, samples were directly used for the determination of fluoride and etc.

Many water samples collected from the tube wells of Kathalal Water Authority.

Seasonal water sampling was done for those samples during pre-monsoon and

monsoon with special reference to fluoride..

Environmental pollutants affect the aquatic ecosystem in a synergistic manner,

which cannot be detected comprehensively by determination of selected physic

chemical parameters alone. Whereas, biological system can integrate all

environmental variables over a long period to times of effects which can be easily

measured and quantified.

Groundwater samples were collected from 127 locations during January-2011

to January 2013 period. Each of the groundwater samples was analyzed for 13

parameters such as Temperature, pH, hardness, total alkalinity, phosphate, chloride,

Calcium, Magnesium, and Nitrate values, C.O.D, total alkalinity, fluoride, Dissolved

oxygen (DO) total dissolved solid (T.D.S.). Using standard procedures recommended

by APHA6.

The physic-chemical parameters of water quality were analyzed using

standard methods given an APHA (American Public Health Association)

The work will be carried out on the following lines

Physico-chemical characterization of river, ground, and surface water such as

pH, Hardness, total alkalinity, phosphate, chloride, Calcium, Magnesium, Nitrate

values, C.O.D, Fluoride, total alkalinity, Temperature, PH , dissolved oxygen (DO)

total dissolved solid (T.D.S)

In the late years ecological screening through standard evaluation of water

quality has turned into a urgent variable in the abuse or preservation of amphibian

assets.

By and large water quality appraisal includes investigation of physical,

synthetic and biotic parameters, which reflects the status of abiotic and biotic

variables of the water repository. This thus, helps in arranging preservation

methodologies.

Because of the steady trade of substances between water repository and its the

earth, it is important to survey and screen ecological health through water quality

appraisal.

Information accumulation

There are two sorts of information accumulation is needed. These are alluded

as Secondary and the essential information accumulation strategies.

Essential information

It alludes to the information which is gathered straightforwardly throughout

the procedure of examination.

Auxiliary information

It alludes to the information sets which recently exist. It is vital to gather

optional information before going into field examinations. It may give helpful data

about the examination and serve as the support. The information may be qualitative,

quantitative or spatial.

� SAMPLING METHODS

Inspecting is a vital apparatus in understanding the water quality. It is greatly

troublesome to dissect the whole water figure and it may not be fundamental either.

A little parcel of water is alluded to as an example which speaks to the entire water

form, is gathered for definite examinations.

Determination of testing locales .

Sampling focuses were chosen by remembering that the recognized testing

focuses must incorporate shallow and profound areas of the water form, purposes of

inflow, and outpouring of water in the supply, human exercises. For profound area

focus or mid a piece of the water figure is chosen and specimen is constantly taken

from medium profundity.

Accumulation of water specimen .

Water examples were gathered throughout morning hours (i.e. 7.00 am to

9.00am) on second Sunday of each month all around the study period from the chose

destinations to focus physico-compound and organic parameters. Samples for

investigation of physico-substance parameters and biotic parameters are taken

independently by applying diverse technique. The system for organic parameters is

talked about somewhere else in this section.

Wide mouthed Polyethylene container is utilized to gather water test for the

different physico-synthetic parameters other than DO. For DO, 500 ml BOD glass

flask with glass plug is utilized to gather the water test. For that BOD flask is initially

flushed with supply water and afterward plunged into water and after that its cover is

shut painstakingly by taking precautionary measures that no air pockets were shaped.

Taking care of and safeguarding of water example

Numerous physical, concoction and biochemical responses may change the

nature of the water example throughout the time of its accumulation time and its

genuine investigation time. To minimize such transforms it is important to save the

examples not long after accumulation. Investigation of a portion of the parameters, for

example, ph and water temp., were performed on the site by utilizing pocket meters

and glass thermometer. To gauge DO, water example is independently gathered in

DO jug as said prior and after that obsession of the same is performed by including

soluble KI, Mnso4 and H2so4 at the site and later on investigation being done in the

research center alongside different parameters by utilizing standard techniques

recommended by APHA (1998); Kumar and Ravindranath (1998); Trivedy and Goel

(1984).

Different methods are utilized to save the water specimens, for example,

expansion of compound additive, dropping down the temperature or a combo of both

the strategies.

Data processing for statistical analysis etc.

Sr.No. Parameters of water

analysis Methods

1 Temperature Thermometric

2 pH Digital pH Meter

3 Ca+2 Hardness Titration (EDTA-Titrimetric)

4 Mg +2Hardness Titration (EDTA-Titrimetric)

5 TDS Digital TDS Meter

6 Total Alkalinity Titrimetric using Indicators

7 Chloride Argenometric

8 Phosphate Spectrophotometric

9 Sulphate Spectrophotometric

10 Nitrate Spectrophotometric

11 Dissolve Oxygen Titratomatric

12 COD Open reflux method

13 F-1 Spectrophotometer

2.1 Temperature:-

In general winter is very cool and dry whereas, summer is extremely hot. May

is the hottest month while, January is the coolest, June to September represent the

rainy months. The mean monthly minimum temperature ranges between 11.0oC

and 27.0oC, while mean monthly maximum temperature ranges between 26oC and

39.9oC. The mean annual temperature ranges between 25oC and 27oC. During

summer intense solar radiation and powerful wind velocity causes dust storms,

resulting in wind erosion of top soil that adversely affects soil fertility and crop

cultivation.

2.2Determination of pH:-

Principle:-

pH is a measure of the relative acidity or alkalinity of water. The quantity pH has

been defined as the common logarithm of the activity of the hydrogen ions. In

sufficiently dilute solution the activity of the ions can be equated with its

concentration in mole/liter i. e.

PH = -log [ H30+]

It may be measured by determining with a potentiometer the voltage developed by

two electrodes which are in contact with the solution. The voltage of one electrode

(reference electrode) known, as a calomel hail-cell is fixed, while the voltage of the

other electrode ( glass electrode) varies the pH of the solution. The glass electrode

system is based on the fact that a change of 1pH Unit produces an electrical charge of

59. 1 my at 25 degree C due to special glass membrane surface.

An aqueous Solution is said to be an acidic if the concentration of hydroniun ion

is greater than 10 moles/lit and alkaline if it is less than 10 moles/lit.

Reference electrode : Ag/Agcl electrode

Glass electrode : Calomel electrode

Source of Error

-Inaccurately prepared standard solution.

-The slope of the electrode response curve decreases with age and contamination

affecting the glass membrane and stop up the diaphragms of the electrodes.

-HF in the water destroys the layer of silica gel on the glass membrane responsible for

the interfacial potential.

-Electrode glass bulb should never be dried.

-Keep the sample bottles closed unless necessary.

-For water almost free from suits (Ceg) 0.5 m mol/lit add 10.25 mg NaCl or 0.25 ml --

-NaCl solution before measuring the pH.

Reagent:-

-Standard buffer solutions of 4.0, 7.0., 9.2 pH

-3 M Potassium Chloride or Nitrate solutions.

-Sodium Chloride or Sodium Chloride solution 100 b/l, prepare all reagents in double

distilled or deionizer water.

Apparatus:-

- PH meter. Combined glass electrode.

-Magnetic stirrer, PTEE coated Magnetic stirring bar.

-Thermometer.

2.3 Determination of Calcium Hardness:- When EDTA is added to water containing both calcium and Magnesium, it

combine first with the calcium that is present. Calcium can be determined directly.

Using EDTA, When the pH is made sufficiently high (12-13 pH) that the magnesium

is largely precipitated as Mg(OH)2 and an indicator is used which combines with

calcium only. Muroxide indicator changes its colour from pink to purple.

Reagents:-

(1) 0.01 M EDTA Solution

(2) IN Sodium Hydroxide

(3) Indicator Muroxide (Ammonium pupurate)

200 gmg muroxide is mixed with 100gm of NaCl and grinding the mixture to

40-50 mesh. The titration should be performed immediately after addition of indicator

because it is unstable under alkaline condition.

Procedure:-

To suitable volume of sample (50ml) add 2.0 ml of IN Na0H EDTA solution

with continuous stirring to the proper end point colour from pink to purple.

Calculation

Ca –Hardness = B.R x 1000

mg/l as CaCO3 ml Sample

Calcium mg/l =B.R x 400.8

(Ca) ml. sample

If the calcium content is known magnesium may be calculated as follows.

Magnesium =Total hardness – (Calcium 2.5) 0.243 mg (mg/l)

Method of Determination of Total hardness is given bellow. By Using of this method we

find out the value of Mg+2.

2.4 Determination of Magnesium (Total Harness) :-

Principle:- The presence of calcium and magnesium salts causes water to be hard, with the

degree of hardness being directly proposnal to the quantity of these heavy metals that

are present.

Hardness the source of scale formation in boiler feed water, heavily scaled due to

precipitation of calcium and magnesium salts unless properly treated. Hardness can be

removed by lime soda softening and ion exchange softening. It may be removed in

internal boiler water conditioning by employing inorganic salts such as phosphate and

carbonate.

The hardness can be determined by EDTA titration method. Sodium salt of

ethylenediamine tetra acetic acid from a chelated soluble complex when added to a

solution of calcium and magnesium ca+2 and mg+2 e complexes the colour of indicator

Eriochrome Black-T at pH of 10.0 – 0. changes from wine red to blue marking the end

point of the titration. Magnesium ion must be present to yield a satisfactory end point.

Hence they are added to buffer in the form of magnesium salt of EDTA. The

sharpness of the end point increases with increasing pH.

Interference:-

Al+3,Ba+2, cd+2, Co+2, Cu+2, Fe+2, Pb+2, Mn+2, Ni+2, Sr+2, Zn+2 Poly Phosphates

interference by causing indistinct end point. Organic matter also interferes.

Reagents :-

(1) Buffer Solutions :-

Dissolve 67.5 gm NH4CL in 570 ml con. Ammonia solution and dilute to 950 ml with

distilled water. Dissolve3.12gm of MgSO4. 7H2O and 4.716 gm of disodium

ethylenediamine tetra acetate dehydrate in 50ml distilled water and add to the

NH4OH. NH4CL solution keep this solution tightly stopper to prevent loss of NH3 or

absorption of atmospheric CO2 and acid fumes.

(2) Slandered EDTA Solution 0.01M :

Dissolve 4.0 gm of disodium ethylene diamine tetra acetate dehydrate (EDTA) and

dilute to 1 liter with distilled water. Standardize against standard calcium solution and

adjust in such a way that 1 ml titrate = 1mg CaCO3

(3)Standard Calcium Solution:-

Transfer 1.000 gm of CaCO3 dried at 105 degree into a 1 liter volumetric flask

containing 200ml of distilled water Through a funnel carefully add small amount of

1:1HCL until all the CaCO3 is dissolved. Boil of the CO2 for a few minutes. Cool and

neutralize solution to methyl red indicator with 3N NH4OH. Dilute to the mark with

distilled water. This gives 1 ml =1 mg CaCO3

(4) Mix 0.5 gm of dye Eriochrome Black T and 100gm NaCl to prepare a dry power

mixture.

Procedure:-

To a suitable volume of sample (50ml). add 1-2 ml of buffer solution so as to get pH

of 10.0-0.1. Add approx 0.2 gm of dry powder indicator (EET) and titrate slowly with

continuous stirring with 0.01 M EDTA solution until the last reddish tinge disappears

from the solution to the solution to the end point blue colour under normal condition.

Calculation:-

T - Hardness mg/L = B.B x 1000

As CaCO3 ml Sample

2.5 Determination of Total, Dissolved and Suspended Solids:-

Principle:-

Total solids represent the sum of the dissolved and suspended solids.

Suspended solids are those solids which are not in true solution and can be removed

by coagulation and filtration. Suspended solids are objectionable in process work,

boiler feed and cooling water conditioning.

Dissolved (filterable) solid usually composed of the sulfate, bicarbonate and

chlorides of calcium, Magnesium and sodium. May produce an effect specific to that

ion dependent on whether the water is employed in process work or as boiler feed or

cooling water. Dissolved solids require demineralization or distillation for minimizing

the ions Filterable residue is material that passes through a standard glass fiber disk or

filter paper and remains after evaporation an drying to constant weight at 180 degree.

Residue dried at 103 degree – 105 degree C often contains some occluded water

sample having an appreciable organic matter content or with a pH in excess of 9.0 are

best dried at 179 degree-181 degree C usually removes most of the occluded water

converts the bicarbonate to carbonate more completely and may result in the loss of

some chloride and nitrate salts.

Procedure:-

(A) Total Solid:

Take the aliquot sample (50ml or 100ml) to yield a residue between 25 to 250 mg

in a previously dried, cool and weighed evaporating dish. Evaporate the sample to

dryness on as team bath and dry to constant weight in an oven adjusted at either 103

degree C or 179 degree-181 degree C consisting heating, cooling and weighing.

Weight the dish after a fixed cooling time in a desiccators. Do not allow the residue to

remain overlong in a dedicator because some residue, especially those dried at 180

degree C are very hydroscopic. Report the residue in mg/L and temperature.

Calculation:-

Total Solid mg/l = wt of residue in mg x1000

(ppm) Ml of the sample taken

at 103 degree- 105 degree C.

(B) Suspended matter and Total Dissolved Solids :-

Filter a known volume of the sample (50 ml or 100ml) through previously dried,

cooled and weighed G-4 sintered glass crucible (or counter poised filter paper) Wash

it with distilled water. Dry the residue at either 103 degree-105 degree C or 179

degree-181 degree C. Cool and weigh

Calculation:-

Suspended matter mg/L = Wt of residue in mg x 1000

ml of sample taken

and TDS (mg/L) = Total Solids- suspended matter

(c) Total Dissolved Solids :-

Take 50 ml or 100ml filtrate filtered through G-4 sintered glass crucible (or

counterpoised filter paper) in a previously dried, cooled and weighed eve\aporating

dish. Evaporate the sample to dryness on a steam bath and dry to constant weight in

an oven adjusted at either 103 degree-105 degree C or 179 degree-181 degree C cool

and weigh.

Calculation:-

T D S (mg/L) = wt. of the residue in mg x 1000

ml of sample taken

2.6 Determination of Total alkalinity:-

Principle:-

The alkalinity of a water is its quantity tie capacity to neutralize a strong acid to a

designated pH. In the case of most natural water samples. The constituents consist of

bicarbonates and to a lesser extent. Carbonate of Calcium and Magnesium. Softening

or corrosion control agents, such as CaO, Na2CO3, Phosphate and Silicate also

contribute alkalinity.

The alkalinity is alerted in two steps, first to the phenolphthalein end point at pH

8.3 and then to the total and point in the pH range to 4 to 5 \either Methyl orange or a

bromo cresol green Methyloreo mixed indicator may be used for the total alkalinity. A

drop 0.1N Na2S203 solution added to remove residual chlorine Alkalinity may be

determined bye electrometric titration to a fiz pH value characteristic of change in

colour of indicator for a sample containing free residual chlorine, having colour and

turbidity.

The presence of high ethyl orange alkalinity in the boiler feed water is to be

avoided because under the influence of heat in the boiler. CO2, and carbonate to CO2

and hydroxide. Carbon dioxide usually is responsible for corrosion. The alkalinity of

boiler feed water should be sufficiently high to protect the boiler metal against acidic

corrosion. Alkalinity results are reported in terms of CaCO3.

Reagents:-

(a) Standard 0.02N H2SO4 or HCL solution.

(b) Phenolphthalein and Methyl orange indicator.

Procedure :-

Take 50ml or 100ml sample into a white porcelain casserole Remove any free

residual chlorine with 0.1N Na2SO4

P. Alkalinity :-

Add 2 drops of phenolphthalein indicator to sample and titrate with 0.02N acid

solution to the disappearance of the faint pink colour characteristic of pH 8.3 Note the

burette reading.

M.Alkalinity: (T. Alkalinity)

Add 2-3 drops of Methyl orange Indicator and continue adding the standard acis.

Until the colour of the solution change to very faint orange colour characteristic of pH

4.5. Note the burette reading.

Calculation:-

Alkalinity as mg/l of CaCO3 = B.R x 1000

Sample in ml

if desired, calculate the approximate bicarbonate, carbonates and hydroxide

concentration by the equation presented in the following table.

Titration

Result

Hydroxide as

CaCo3 Carbonate as CaCo3

Bicarbonate as

CaCo3

P = 0

P < 1/2 T

P = 1/2 T

P > 1/2 T

P = T

0

0

0

2P-T

T

0

2P

2P

2(T-P)

0

T

T-2P

0

0

0

(p=p Alkalinity, T=T Alkalinity)

2.7 Determination of Chloride:-

1. By Mohr’s Method:-

The chloride of calcium, Magnesium, Sodium Iron and other cations normally

found present in water are extremely soluble. A high chloride content also exerts a

deleterious effects on metallic pipes and structures as well as on agriculture plants.

The principle applications of the test is

(a) In the control of blow down in boiler and cooling systems

(b) To estimate the percent make up in a boiler and cooling systems.

(c) In control of Ion exchange softeners (d) In determining condenser leakage water is used for condensing purpose.

In the neutral or slightly alkaline solution pH range 6.5 to 9.01 Potassium.

Chromate can indicate the end point of the silver Nitrate titration of chloride. When

all the chloride When all the chloride has gone into combination as age an excess of

Ag NO3 with excess of K2CrO4 immediately forms the reddish brown Ag2CrO4 how

the end point.

(B) Determination of Chloride Spectrophotometrecally:-

Reagents:-

1. 1.5 gms. Mercuric Thiocyanate Hg(SCN) in 500 ml methanol is dissolved by

keeping it for two days.

2. Ferric Alum Solution

Take 50 gm Ferrous Ammonium Sulfate. Add 380ml HN03 Boil and Cool,

make it 1 liter.

3. Preparation of standard Solution.

(A) Dissolve 0.824gms of previously dried NaCl in distilled water and make 1 liter

volume in the volumetric flask. This solution is of 1ml = 0.5mg Chloride

(B) Take 25ml of solution (A) in 1 liter volumetric flask and make the volume up

to the mark with water. This solution is of 1 ml = 0.0125 mg Chloride.

(C) Take 50 ml of solution (B) in 250ml Volumetric flask and make the volume up

to the mark.

1 ml = 0.0025 mg Chloride

Reaction :-

Cl + Hg (SCN) HgCl + SCN

Ferric Thiocyanate

(reddish brown)

Ag2 CrO4 + 2NaCl decomposition

2AgCl + Na2CrO4

Reagents :-

1. 1ml AgNO3 = 1 mg Cl (or 1 ml AgNO3 = 0.5 mg Cl) Dissolve 4.795 gms of Silver

Nitrate into 1 liter volumetric flask with distilled water and dilute up to the mark.The

solution can be standardized against standard sodium chloride solution containing

1.649 gm NaCl in 1 liter of solution. This is 1 ml AgNO3 = 1 mg Cl 2. 5% Potassium

Chromate Solution in water.

Procedure:-

Prepare a colour comparision blank in a white porcelain casserole by stirring 1

ml K2CrO4 indicator with standard AgNO3 solution (1ml = 0.5 mg Cl ) into a 100ml

distilled water. Pipette into a similar white porcelain casserole an aliquot sample

diluted to 100ml containing not more than 10mg Cl Add 1 ml K2CrO4 indicator and

starring constantly titrate with standard AgNO3 solution (1ml =0.5mg Cl) to the

colour of the comparison blank reddish brown colour.

Calculation:-

Cl mg/l = (A – B) X 0.5 X 1000 ml of sample

Where

A = ml of titration for sample

B = Blank.

Calibration Curve for Chloride :-

Take 1,2,4,8,12,16,20,24,ml of standard solution ©, 1ml = 0.0025 Cl in

nessler s tube. Make up the volume 25 ml in all nessleers tube with chloride free

water. Then add 5ml ferric alum solution. Mix well and add 2.5 ml Mercuric

thiocynate solution mix well. After 10 min measure the colour concentration at the

wavelength.

Procedure:-

Take aliquot sample (5ml) in nessler’s tube. Make it 25ml with water. Then

add 5.0 ml ferric alum solution. Add 2.5ml mercuric thiocyanate solution Prepare a

Blank set. Don’t make further dilution measure the colour concentration at the

wavelength 463nm in 50mm cel. After 10 min.

Calculation:-

Cl mg/l = mg from graph x 1000

ml at sample

2.8 Determination of Phosphate:- The phosphate ion rarely occurs naturally in a raw water. In cooling water

system, the polyphosphates are employed to prevent precipitation of calcium

carbonate which results in scale formation. Also it is used for control of tuberculation

and some reduction in corrosion while in boiler feed water phosphate is added to react

with calcium to form insoluble tricalsium phosphate at pH value of 9.5 or higher. In

other words. In order to completely precipitate the calcium hardness. The

determination of phosphate usually is made in order to control chemical treatment

containing phosphate.

Principle:- Orthophosphate reacts with Ammonium molybdaten in an acid medium to from a

Molybdohosphate which in turn is reduced to a Molybdenum blue complex with 1-

Amino-2-Naphthol-4-Sulphonic acis. The colour intensity is proportional to that of

the phosphate concentration pyre, ets and triphosphate can be made to react in the

rest. If it is hydrolyzed to ortho from by boiling the acidified sample. Thus the

polyphosphate content of the water can be calculated by sub starting the ortho

phosphate found in a un boiled sample from the total phosphate found in a acidified

boiled sample. Colour, turbidity, Arsenic must be absent in this colourometric

method. Residual bromine and chloride should be removed by boiling silica yields

and additive colour. Haxavalent chromium may interfere at P04 levels below 1 mg/l

Reagents :-

i. Standard Phosphate Solution

(a) Dissolve 0.7165gm KH2PO4 dried at 105 degree C in distilled water and dilute to

1000ml. Add 5gm of CHCl3 i.e. ml= 0.5mg PO4-3

(b) Prepare a standard solution from above stock having 1 ml = 0.05mg PO4 by

diluting 25ml of solution (a) to 250ml.

ii. Strong Acid Solution for Polyphosphate Cautiously add 300ml concentrated H2SO4

to 600ml distilled water. Cool to room temperature and add 4.0ml of con. HNO3 and

dilute to 1000ml.

iii. Phenolphthalein indicator

iv. 20% H2SO4 Solution

v. Ammonium Molybdate

(a) Dissolve 31.4gm Ammonium Molybdate in 200ml of distilled water.

(b) Cautiously add 225ml of conc. temperature add 3.4ml con. HNO3. Add solution

(a) solution (b) never the reverse and dilute tool liter.

(vi) ANSA SALUTION: (1 Amino-2-Naphthol-4-Sulphonic acid)

Weigh out separately 0.75gm 1-Amino-2-Naphthol-4-Sulphonic acid, (use a

powder no darker than a pale pink in colour) 42gm Na2SO3 and sodium metabisulfite

70gm (Na2S2O5). Pulverize the Amino Naphthol sulphonec with a small portion of the

Na2S2O5 in a clean, dry, mortar. Dissolve the remaining Na2SO3 and Na2S2O5 in

900ml distilled water, and the finely ground Amino Naphthol Sulphonic acid.

Na2S2O5 mixture and atir to dissolve. Dilute to 1 liter. Store in brown glass stopper

bottle at a temperature below 30 degree C.

Calibration Curve:-

Use standard PO4 solution (b) (1ml = 0.05mg PO4-3 ) as follows Take 2,6,8.10ml

standard solution in Nessler s tubes and add 2ml 20% H2SO4 then add 2.0ml

Ammonium Molybdate solution. Mix well and after 5min add 2.0ml 1 Amino 2-

Naphthol 1 -4-Sulphonic acid solution and dilute to 50ml mark and measure the

absorbance at 660nm wavelength in 10mm cell after 30 min.

Procedure:-

Take aliquot sample (5ml to 25ml) in 100 ml nessler s tube containing PO4

content about 0.0025 to 0.5mg add 2 ml. 20% H2SO4 and than add 2.0ml Ammonium

Molybdate reagent and mix well After 5 min add 2.0ml Amino Naphthol Sulphonic

acid and dilute to 50ml mark. Mix well. After 30min read the absorbance at 660

Wavelength in 10mm cell.

Calculation:-

PO4 -3mg/l = mg PO4 (from graph) x 1000

ml of sample

2.9 Determination of sulfate:-

Principle :-

Sulfate is widely distributed in nature and may be present in natural water in

concentrations varying from few to several thousand mg/liter.

The principal objection to the sulfate ion in water is its acidity to combine with

calcium to form calcium sulfate scale. The most common constituent of boiler scale in

an untreated boiler is calcium sulfate. The prevention of calcium sulfate scale is

possible by the removal of either calcium or sulfate in industrial water conditioning it

is much simpler and more economical to remove the calcium than the sulfate. The

sulfate can be removed by demineralization.

Sulfate can be determined by gravimetric or turbid metric method. The turbid

metric method. is sufficiently precise, rapid and simple for routine use in the SO4

range 5 to 60 mg/lit.

The T-SO4 is determined by spectrophotometer developing the turbidity of barium

sulfate. The velocity of the precipitation as well as the concentration of reactants,

must be controlled by adding pure solid barium chloride of definite arain size. Sodium

chloride and hydrochloric acid are added before the precipitation in order to inhibit

the growth of micro crystals of barium sulfate. The optimum pH is maintained and

minimizes the effect of variable amounts of other electrolytes present in the sample

upon the size of the suspended barium sulfate particles. A Glycerin solution helps to

stabilize the turbidity. Each flask should be shaken at the same rate and the same

numbers of times gently in order to obtain the uniform particle size. The interval

between the time of precipitation and measurement must to kept constant.

Reagents :-

1. Conditioning Reagent with a solution containing 30 ml con. HCl, 300ml

distilled water and 75gm of sodium chloride.

2. Barium chloride crystals 20-30 mesh BS

3. Standard sulfate solution.

Standard Solution :-

1000 ml H2SO4 = 49gm H2SO4 = 48gm SO4

1 ml 1N H2SO4 = 0.049gm H2SO4 = 0.048gm SO4

1 ml 1N H2SO4 = 0.245gm H2SO4 = 0.24gm SO4

1 ml 1N H2SO4 = 0.0245 x of H2SO4 = 0..24 f.H2SO4

0..245 x of. H2SO4 = 7ml N2 x f. H2SO4

1 gm H2SO4 = 40.81ml N/2 H2SO4

F=1 = 1gm SO4.= 41.67 ml N2H2SO4

40.8ml N2H2SO4 = 1gm H2SO4 = 1000mg H2SO4

20.4 ml N2H2SO4 = 0.5mg H2SO4 = 500mg H2SO4

20.8 ml N2H2SO4 = 0.5gm H2SO4=500mg SO4 (in 500ml)

For 1ml = 1mg SO4 Transfer 20.8ml N2H2SO4 to 500ml vot flask dilute to the mark

by d.w. Dilute 25ml of solution (A) to 500ml by D.W. i.e. the solution is 1ml= 50 ug

SO4

Calibration curve:-

Low range Transfer 5, 10, 15, 20, 25, 50ml of the standard sulfate solution

(1ml =50ug SO4) in five different 100ml volumetric flasks, Dilute to about 50ml with

distilled water Add 5ml 1:1 HCl and then add 5ml of the conditioning reagent and

dilute to the mark with distilled water. Mix well. Add 0.3 gm of theBac12 crystals and

shake the flasks carefully for one minute i.e.30 times by inverting the flask. After four

minutes invert the flask for 5 times to shake and observed the %T at 420 mu

wavelength using 20mm cell adjusting the reagent blank at 100%T Plot a calibration

carve of Ug sulfate against optical density. High Range : Transfer 0, 5, 10, 15, 20,

25ml of 1ml = 0.2mg SO4 in diff. 100ml vol. flask. Proceed as above. Take 50ml of

solution (A) and dilute to 250ml, this will give 1ml = 0.2mg solution.

Procedure:-

If necessary, remove suspended matter by filtering the sample. Transfer a

sample volume containing 0.5 to 1.0mg SO4 into a 100ml volumetric flask dilute to

50ml. Add 5ml 1:1 HCl and 5ml of the conditioning reagent and dilute to the mark

add 0.3gm of Bac12 crystals and determine the mg SO4 in the sample from the graph

proceeding according to the calibration curve.

Calculation:

SO4 mg/l = Ug of SO4 x 1000

Sample in ml x 1000

2.10 Determination of Nitrate in water:-

Principle:- The nitrate ion is Present in natural waters in relatively small quantities.

Nitrogenous compounds may be introduced with sewage with the subsequent

oxidation of these compounds to nitrate. In industries water conditioning, the nitrate

ion does not possess much significance except it is used to control embrittlement. The

nitrate concentration of most drinking waters usually falls below 10mg/l.

The phenol disulfonic acid method can be applied to the determination of nitrate

over a fairly wide range to the small amounts below 1mg/l. Yellow colour is Produced

by the reaction between nitrate and phenol disulfonic acid in an alkaline solution.

Except coloured ions, the chief interference with this method include nitrite, chloride

and organic matter.

NO3-

+

OH SO3H

SO3H

+ 3KOH

KO SO3K

SO3K

O2N + 3OH-

Reagents:-

(1) Phenol Disulfonic Acid :25% Solution of phenol disulfonic acid OR Dissolve

25gm Pure phenol in 150ml of conc. H2SO4, Add 75ml fuming H2SO4 (15%

/\rree SO3), Stir well, and heat for 2 hour on a water bath..

(2) 12N Potassium Hydroxide :67.2 gm dissolved in water and make it 100ml.

(3) Standard Nitrate Solution :Dissolve 0.3258gm of anhydrous KNO3, and dilute

to 1000ml with distilled water.

i.e. 1ml = 0.2 mg Nitrate – NO3 (A)

Evaporate 50ml of this stock solution (A) to dryness on a water bath. Dissolve

the residue by rubbing with 2.0 ml. of phenol disulfonic acid reagent and dilute to

1000ml with distilled water.

i.e. 1ml = 0.01mg Nitrate-----------(B)

dilute 50ml of solution (B) to 250 ml with distilled water

i.e. 1ml = 0.002 mg Nitrate---------(C)

Calibration Curve :- (a) for 0-0.1 mg Nitrate : (Low Range)

Transfer 0, 10, 20, 30, 40 and 50ml of the standard solution © (1ml = 0.002 mg

N03) into different 100ml volumetric flasks. Add 2ml of Phenol disulfonic acid

and dilute to about 50ml Add 10ml of 12N KOH Solution. Dilute up to the mark,

and mix well. Allow to stand for half an hour and measure %T of 410nm

using 50mm cell adjusting reagent blank at 100% T. Plot a graph of O.D. against

concentration of nitrate.

(b) For 0-0.8 mg Nitrate : (High Range)

Transfer 0, 10, 20, 40, 60 and 80ml of the standard solution (B) 1ml = 0.01mg Nitrate

into different 100ml volumetric flasks, Add 2ml of phenol disulfonic acid and 10ml of

12 N KOH solution. Dilute to the mark. Mix well. Measure %T at 480 nm using

10mm cell after half an hour Plot a graph of O.D. against concentration of nitrate.

Procedure:-

Evaporate an aliquot (25ml) of the sample to dryness on water bath in 100ml

beaker. Add 2ml of Phenol disulfonic acid and rub the residue with the help of glass

rod and dissolve. Transfer into 100ml volumetric flask with about 20-30 ml distilled

water. Add 5ml of 12N KOH, dilute to the mark and mix it well. Measure %T at 480

nm using 10mm cell after half an hour. From graph measure the mg of Nitrate.

Calculation:-

Mg/l Nitrate = mg of nitrate from graph x 1000

ml of the sample taken

2.11 Determination of Dissolve Oxygen:-

Principle:-

The term “Dissolved Oxygen” represents the amount of oxygen gas actually

dissolved in water and is in no way related to the combined oxygen present in the

water molecule H2O. Dissolve oxygen is present in all surface waters and rain waters

due to their contact with the atmosphere. Distilled water will absorb more oxygen

than water containing higher solid content. Aeration is employed for the removal of

gases such as CO2 and H2S results in saturation of water with dissolved oxygen.

Dissolve oxygen is objectionable in water used for industrial purposes because of the

corrosive effect on iron and steel with which the water comes in contact.

Elimination of corrosive effect of dissolved oxygen can be accomplished by both

direct and indirect means. The direct means involves the actual removal of D.O. by

mechanical or chemical demarcation. The mechanical desecration involve the raising

the water to boiling temperature and continuously venting the mixture of gases and

steam from a properly designed heater. While in chemical demarcation, sodium sulfite

and hydrazine are used to react with oxygen to form sodium sulfate and water

respectively. The indirect means involve the use of corrosion inhibitors like chromate

salts which forms a mixed oxide film on the metal surface is rendered passive to

oxygen attack. Alkaline chemicals can also be used for the development of a

protective scale film to prevent contact of D.O with the protective surface.

This dissolved oxygen in water can be determined by two methods.

(1) Wrinkler’s iodometric method

(2) Indigo carmine method

(A) Dissolved Oxygen in water by Colorimetric Indigo - Carmine

Method: ( For Lower Concentration)

This method is applicable to water solved O2, such as steam condensate and

desecrated boiler feed water.

Dissolved oxygen reacts under alkaline conditions with the indigo carmine

solution to produce a progressive colour change from yellow green through red to

blue and blue green. The result of each test can be determined by comparison of

colour developed in the sample with colour standards made up to represent different

concentrations of dissolved oxygen.

Interferences:-

Tannin, hydrazine and sulfite do not interfere in concentrations up to 1 PPM

Ferric ion, Cyclohexylamine and Morph line in concentrations up to 4 PPM can be

tolerated Ferrous ion will produce low results. In samples copper will cause high

results. In samples where ferrous ion and copper are present, their combined

interference is frequently zero.

Apparatus:-

60ml Special type of burette.

Reagents :-

(a) Colour Standards, stock solutions as follows.1.Red colour standard. No CS-A

Dissolve 59.29gm of cobaltous chloride hexahydrate (COC12 , 6H2O) in

sufficient HCL (1.99) HCl:H2O to make 1 liter.2.yellow colour standard, No

CS – B

Dissolve 45.05gm of ferric chloride hexahydrate (FeC13 C H2O) in sufficient

HCl (1.99) HCl : H2O to make 1 litter.

(b) Hydrochloric acid : Concentrated (Sp. Gr.1.19)

(c) Hydrochloric acid (1.99) : Mix 1 volume of concentrated HCl with 99

volumes of water.

(d) Indigo Carmine Solution :

Dissolve 0.18mg of 100 percent indigo carmine and 2.0gm of dextrose (or

glucose) in 50ml of water. Add 750ml of glycerin and mix thoroughly, the

solution is usable for at least 30 days if stored in a refrigerator.

(e) Indigo Carmine – Potassium Hydroxide Reagent :

In a small bottle mix four parts by volume of indigo carmine solution with one

part of the potassium Hydroxide (KOH) solution (f) stopper and invert several

times until mixture is complete. Allow the reagent to stand un-disturbed until

the initial red colour changes to lemon yellow. Keep in a dark cool place.

Prepare a fresh solution daily.

(f) potassium Hydroxide Solution :

Dissolve 530gm of potassium Hydroxide (KOH) in water and dilute to 1 liter.

Standard Stock Solution : (Tabe-1)

Equivalent Dissolved

oxygen, PPM

Milliliters of colour Standards

CS-A CS-B CS-C

0.000 0.75 35.0 -

0.010 6.25 12.5 -

0.020 13.0 6.4 -

0.030 14.6 3.3 0.2

0.040 15.5 2.4 2.2

0.050 18.3 1.7 8.1

0.060 25.0 1.0 18.0

Prepare a series of colour standards as listed in table Place the amounts of

stock solution listed in table-1 in 300ml borosilicate glass stopper reagent, bottles.

Add 2-3ml HCl (Sp. Gr. 1.19) to each and dilute to the neck of the bottle with water.

Stopper with plastic or lightly lubricated glass stoppers and mix by inversion. Store in

a dark place to minimize finding of colours.

Procedure:-

Place the indigo carmine KOH mixture in a small tube which is inside the

burette. Fill it completely, Place a small glass ball on it by taking care that not a single

air bubble remains in the small tube (Doesn’t matter if the solution gets overflow)

Sampling:-

If possible, use stainless steel tubing for the sample line. The water which is to

be sampled should be at room temperature. Suitable cooling system must be there.

The sample flow shall be adjusted to a rate that will fill the sampling burette in 40 to

60 sec, and flow long enough to provide a minimum of ten changes of water in the

sample burette. The sampling tube should be connected at bottom end of the burette.

When sufficient flushing is over, close both the cock of burette, Ie. top and bottom

cock at a time. Invert the burette so that indigo carmine reagent comes out from small

tube and invert it for several times to mix indicator with water. Compare the

developed colour with standards and find out dissolved oxygen present.

NOTE: This method is generally used for Desecrator samples, which contains

dissolves oxygen less than 0.060 PPM.

(B) Dissolved oxygen: Indometric Method: (For higher concentration)

-------------------------------------------------------------- This method is applicable to industrial water containing more than 0.05 PPM

of oxygen and having low concentrations of reducing & oxidizing materials.

Principle:-

The sample is collected in a HOD bottle. The iodine librated in an amount

equivalent to the oxygen in the sample is titrated with thiosulfate using starch as an

indicator.

Reaction:-

MnSO4 + 2 KOH Mn (OH)2 + K2SO4

2Mn (OH)2 + O2 2Mn O (OH)2

Mn O(OH)2 + KI + H2O Mn (OH)2+I2+2KOH

I2 + 2S2O3-2 S4O

-2 + 2I

Apparatus:-

(i) 800ml BOD Bottle having a raised lip around the neck and a glass stopper

ground to a conical lower tip.

(ii) 2ml, 5ml, Pipettes, burette.

(iii) 250ml, 500ml Conical flask

(iv) Volumetric flask, cap, 100ml 500ml, 1 Liter.

Reagents:-

(a) Monogamous Sulfate Solution :

Dissolve 364 gm Monogamous sulfate (MnSO4, H2O) in water, filter and dilute to 1

Liter. No more than a trace of Iodine should be librated when the solution is added to

an acidified potassium iodide (KI) solution.

(b) Potassium Iodide, Alkaline Solution :

Dissolve 700 gm KOH in sufficient water to make approximately 700ml of

solution in a 1 liter volumetric flask. Cool to room temperature. Dissolve 150 gm of

mix with the KOH solution in the volumetric and store in a dark, rubber stopper

bottle.

(c) Sulfuric acid (3:1) :

Pour carefully 750ml of concentrated sulfuric acid into 250ml of water in a

beaker. Cool to room temperature, transfer toa 1 liter flask and dilute to the mark with

water.

(d) Sodium Thiosulfate. Standard Solution (0.01N):

Dissolve 25gm Na2S2O3 in 1000ml d. water. This will be 0.1N Na2S2O3. find

out its factor than considering it s factor, prepare exact 0.01N Na2S2O3. by giving ten

times dilution.

(e) Starch Solution (1-2%) :

To 100ml boiling distilled water, and a paste prepared by taking 1 to 2gm in

minimum cold distilled water. Cool it and use.

Procedure:-

Connect the source of the sample to a length of glass tubing slightly longer than

the depth of the 300ml BOD Bottle. Put the glass tubing into the and allow the bottle

to fill and overflow, with the water entering at the bottom, until there have been at

least ten changes of the contents. Wet the stopper and than slowly withdraw the glass

tube while the sample continue to flow through it. As soon as the tip of the tube clears

the liquid surface, ease the stopper into the neak and let it float light, invert the bottle

and inspect for air bubbles. If air can be seen, discard the sample and collect another.

To this, add 2ml alkaline KI solution with the pipette filled to the tip so that no

bubble of air will be forced into the sample, ease the bottle stopper out of its seat and

simultaneously thrust the pipette tip past it and into the neck of the bottle. Allow

the contents of the pipette to drain the bottle and as the level in the pipette

approaches that in the bottle, raise the pipette out of the bottle and let the stopper fall

back into its seat. Add 2ml MnSO4 solution in the same way. Seat the stopper lightly

and shake or rotate the bottle to mix the contents thoroughly. Allow the bottle to stand

and. When the precipitates have settled below the shoulder of the bottle, add 2ml of

H2SO4 (3:1) in the same way Stopper and shake until all precipitates are dissolved.

(Addition of reagents should be completed within 15 minutes after sampling)

Take 200ml of this solution from bottle or 300ml depending on the content of

dissolved oxygen present; titrate against 0.01N Na2SO4 solution using starch as

indicator. Blue colour shows end point.

Calculation:-

D.O. mg/liter: A x N x 8000

B

Where A = B.R of thiosulfate solution

N = Normality of std. Na2S203 solution

B = ml of corrected sample aliquot

B is calculated as under suppose 200ml aliquot is taken from 300ml bottle corrected

sample aliquot.

B = 200 x 300

300-Y

Here y represents the total volume of reagents added to the sample bottle (i.e. we have

added 2ml alkaline KI + 2ml MnSO4 reagents SO, Y = 2 + 2 = 4).

2.12 Determination of Chemical Oxygen Demand (COD)

Principle

The chemical oxygen demand determination provides a measure of the oxygen

equivalent of that portion of the organic matter in a sample that is susceptible to

oxidation by a strong chemical oxidant. It is an important rapidly measured parameter

for stream and industrial waste studies and control of waste treatment plants.

The dichromate reflux method has been selected for the COD determination

because it has advantage over other oxidants in oxidizability, applicability to a wide

variety of samples and ease of Manipulation. In this method a sample is refluxed with

know amounts at potassium dichromate and sulfuric acid and the excesses of

dichromate are titrated with ferrous Ammonium Sulfate. The amount of oxide able

organic matter measured as oxygen equivalent is proportional to the potassium

dichromate consumed. Straight chain aliphatic compounds aromatic hydrocarbons and

pyridine are not oxidized to any appreciable extent.

The straight chain compounds are more effectively oxidized when silver

sulfate is added as a catalyst. However silver sulfate reacts with Cl, Br and I to

produce precipitates which are only partially oxidized by the procedure. The oxidation

and other difficulties caused by the presence of chlorides in the sample may be

overcome by adding mercuric sulfate to the sample before refluxing. These ties up the

chloride ion as a soluble mercuric chloride complex. Which greatly reduces its ability

to react further.

Reagents:-

(a) Standard Potassium Dichromate Solution 0.25N Dissolve 12.259 gm K2Cr2O7

in distilled water and dilute to 1000ml (As Nitrite Nitrogen exerts a

COD of 1.14 mg per mg Nitrite Nitrogen exerts a COD of 1.14 mg per

mg Nitrite Nitrogen hence sulfuric acid in the amount of 10mg

for every 1 mg of Nitrite Nitrogen in the refluxing flask may be added

to the Dichromate Solution)

(b) Sulphuric Acid

Conc. H2SO4 containing 22gm Ag2 SO4 per 2.5lit bottle.

(c) Ferrous Ammonium (0.1N) Solution:

Dissolve 39gm Fe (NH4)2 (SO4)2 6 H2O In water. Add 20ml conc. H2SO4 cool

and dilute to 1 liter. Solution must be standardized against the standard

potassium dichromate solution daily.

(d) Ferroin Indicator:

Dissolve 1.485 gm 1-10 Phenanthroleion monohydrate, together with 695 mg

FeSo4 7H2O in water and dilute to 100ml.

(e) Mercuric Sulfate:

Procedure:-

Take 20ml of the sample or an diluted to 20ml in a 250ml flask with ground

glass neck and fitted with a reflux condenser. The amount of sample taken should

have a COD less than 1000 mg/l Add 10ml of 0.25N K2Cr2O7 solution and 30ml of

conc. H2SO4. The acid should be added in a small amounts carefully mixing after each

addition. Add 0.4gm of Mercuric Sulfate and a few glass beads. Attach the flask to the

condenser and reflux for two hours. Cool and wash down the reflux condenser with

25ml distilled water.

Transfer the contents to 500ml flask, dilute to about 150ml and titrate against

Ferrous Ammonium Sulfate Solution using 2-3 drops of ferroin indicator. The colour

change is from bluish green to reddish brow. Carry out blank determination.

Calculation

Mg/liter COD = (Blank-B.R) x Normality of FASx 8000

ml of the sample taken

Sample size

ml

0.25Std.

K2Cr2O7 ml

Conc. H2SO4

with HgSO4 gm

Normality of

F A S

Final volume

before

titration ml

10 5.0 15 0.2 0.05 70

20 10.0 30 0.4 0.10 140

30 15.0 45 0.6 0.15 210

40 20.0 60 0.8 0.20 280

50 25.0 75 1.0 0.25 350

2.13 Determination of Fluoride:- A Colorimetric method, viz., SPADNS was used for analysis of fluoride. It is

based on the Principle that fluoride ion changes the colour of Zirconium-SPADNS

complex, and the colour change is proportional to the fluoride ion concentration.

Under acidic conditions, fluorides (HF) react with Zirconium-SPADNS solution [2-

(4-sulpho phenyl azo) 1,8-dihydroxy3, 6-naphthalein disulphonic acid trisodium salt]

and the 'tale' (colour of SPADNS reagent) gets bleached due to the formation of Zr

F6. Since bleaching is a function of F- ions, it is directly proportional to the

concentration of fluoride.

Absorbance was measured using Spectrophotometer at wavelength 570 nm

(h,,,) and fluoride was evaluated from the calibration curve constructed.