Environmental Engineering Manual Prepared by: Mr. Sandeep Siwach Approved by: Dr. Arabinda Sharma

Transcription

1 2014 Environmental Engineering Manual Prepared by: Mr. Sandeep Siwach Approved by: Dr. Arabinda Sharma BRCM College of Engg & Technology Bahal , Bhiwani Haryana

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

3 EXPERIMENT NO:-1 OBJECT: To determine the ph of the given water sample. 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 moles/litre. Hence in a pure or a neutral water, the quantum of H + and OH - will each equal to =10-7 moles /litre.the ph value of such a pure water will be equal to log 10 1/10-7 = log 10 7 = 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 Prepared By: Sandeep Siwach 3 Approved By: Dr. Arabinda Sharma

4 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) Prepared By: Sandeep Siwach 4 Approved By: Dr. Arabinda Sharma

5 EXPERIMENT NO:-2 OBJECT: To determine the Turbidity of the given water sample. 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. (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 Prepared By: Sandeep Siwach 5 Approved By: Dr. Arabinda Sharma

6 EXPERIMENT NO:-3 OBJECT: To determine the Acidity of the given water sample. 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 CaCO 3. (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 Prepared By: Sandeep Siwach 6 Approved By: Dr. Arabinda Sharma

7 AT ROOM TEMPATURE SAMPLE INITIAL READING FINAL READING VOLUME USED OF NaOH AT BOILING TEMPERATURE SAMPLE INITIAL READING FINAL READING VOLUME USED OF NaOH Prepared By: Sandeep Siwach 7 Approved By: Dr. Arabinda Sharma

8 EXPERIMENT NO:-4 OBJECT: To determine the Alkalinity of the given water sample. 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 0.02NH 2 SO 4 using phenolphthalein and methyl orange indicators. Ca(OH) 2 + H 2 SO CaSO 4 + 2H 2 O 2CaCO 3 + H 2 SO Ca(HCO 3 ) 2 + CaSO 4 Ca(HCO 3 ) 2 + H2SO CaSO 4 + 2CO 2 + 2H 2 O REAGENTS: (i) Sulphuric acid 1N: Place 28ml conc. H 2 SO 4 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.H 2 SO 4 (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 H 2 SO 4 = 1.0mg CaCO 3 (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. (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. Prepared By: Sandeep Siwach 8 Approved By: Dr. Arabinda Sharma

9 CALCULATIONS: SAMPLE PHENOLPHTHALEIN ALKALINITY (P) INITIAL FINAL READING VOLUME OF H 2 SO 4 READING USED SAMPLE METHYL ORANGE ALKALINITY (M) INITIAL FINAL READING VOLUME OF H 2 SO 4 READING USED If the sulphuric acid used for titration is exactly 0.02 N, Phenolphthalein alkalinity (as CaCO 3 ) mg/l (P) Phenolphthalein Alkalinity as (CaCO 3 ) mg/l = (T) Total Alkalinity as (CaCO 3 ) 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- Bicarbonatealkalinity alkalinity alkalinity as Ca CO 3 as CaCO 3 as CaCO 3 P = 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). Prepared By: Sandeep Siwach 9 Approved By: Dr. Arabinda Sharma

10 EXPERIMENT NO:-5 OBJECT: To determine the Hardness of the given water sample. EDTA TITRIMETRIC METHOD: 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. Ca 2+ + H 2 Y CaY H + (EDTA) Mg 2+ + H 2 Y MgY H + MgD + + H 2 Y 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 CO 2 on 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 noncarbonate 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. Prepared By: Sandeep Siwach 10 Approved By: Dr. Arabinda Sharma

11 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 CaCl 2 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. (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 SAMPLE INITIAL READING FINAL READING VOLUME USED OF EDTA PERMANENT HARDNESS SAMPLE INITIAL READING FINAL READING VOLUME USED OF EDTA Prepared By: Sandeep Siwach 11 Approved By: Dr. Arabinda Sharma

12 CaCO 3 (Unboiled sample) Permanent CaCO 3 (Boiled sample) Temporary Hardness = - Prepared By: Sandeep Siwach 12 Approved By: Dr. Arabinda Sharma

13 EXPERIMENT NO:-6 OBJECT: To determine the Chlorine dose required for a given water sample. 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. (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 - )= Prepared By: Sandeep Siwach 13 Approved By: Dr. Arabinda Sharma

14 EXPERIMENT NO:-7 OBJECT: To determine the Total Solids, Suspended Solids and Total Dissolved Solids of a given water sample 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 (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. Prepared By: Sandeep Siwach 14 Approved By: Dr. Arabinda Sharma

15 CALCULATION: Total Solids Sample Volume = 50 ml Mass of empty petriplate (A) =.. gm Mass of empty petriplate + Residue =.. gm (Y) Concentration = (B-A) = =.. gm Total Solids (mg/l) = Suspended Solids Mass of filter paper (C) =.. gm Mass of filter paper + Residue (D) =. gm (X) Concentration = (D-C) = =. gm Total Solids (mg/l) = Total Dissolved Solids = (Y-X) = Total Solid-Suspended Solid Prepared By: Sandeep Siwach 15 Approved By: Dr. Arabinda Sharma

16 EXPERIMENT NO:-8 OBJECT: To determine Chloride Concentration in a given water sample. SILVER NITRATE METHOD: 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. AgNO 3 + Cl AgCl + 2KNO 3 2AgNO 3 + K 2 CrO Ag 2 CrO 4 + 2KNO 3 APPARATUS: Burette with stand Pipette Measuring Cylinder (100ml) Two Conical Flasks N/35.5 AgNO 3 Solution (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, AgNO 3 in distilled water and make up to 1000ml in a volumetric flask. Standardize it against N sodium chloride solutions 1.0ml of exactly N AgNO 3 = 1.0mg Cl (ii) Potassium Chromate Indicator Solution: Dissolve 25gm potassium chromate (K 2 CrO 4) 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. (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. Prepared By: Sandeep Siwach 16 Approved By: Dr. Arabinda Sharma

17 CALCULATION: Equivalent Weight of Chloride = Normality of AgNO 3 =N/35.45 Chloride Conc. CaCO 3 = Sample Blank (Dist.Water) INITIAL READING FINAL READING VOLUME USED OF AgNO 3 Sample Sewage Sample INITIAL READING FINAL READING VOLUME USED OF AgNO 3 Prepared By: Sandeep Siwach 17 Approved By: Dr. Arabinda Sharma

18 EXPERIMENT NO:-9 OBJECT: To determine Sulphate Concentration in a given water sample. 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 BaSO 4. BaCl 2 + SO BaSO 4 + 2Cl - REAGENTS: (i) Methyl Red Indicator: Dissolve 5.0gm methyl orange in 1.0 litre of distilled water. (ii) Hydrochloric Acid, (iii) Barium Chloride 5%, Dissolve 25gm barium chloride dihydrate BaCl 2.2H 2 O in 500ml distilled water. (If any turbidity appears on standing reject the solution). (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 with HCl using methyl red indicator (to orange colour). Then add additional 2ml, HCl. The samples are acidified to eliminate the precipitation of BaCO 3 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 C for atleast 30 minutes. (vi) Dry the filter paper and weigh. CALCULATION: mg/l sulphate as SO 4 2- = Prepared By: Sandeep Siwach 18 Approved By: Dr. Arabinda Sharma

19 EXPERIMENT NO:-10 OBJECT: To determine the Acidity of a given sewage sample. 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 CaCO 3. (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 Prepared By: Sandeep Siwach 19 Approved By: Dr. Arabinda Sharma

20 AT ROOM TEMPATURE SAMPLE INITIAL READING FINAL READING VOLUME USED OF NaOH AT BOILING TEMPERATURE SAMPLE INITIAL READING FINAL READING VOLUME USED OF NaOH Prepared By: Sandeep Siwach 20 Approved By: Dr. Arabinda Sharma

21 EXPERIMENT NO:-11 OBJECT: To determine the Alkalinity of a given sewage sample. 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 0.02NH 2 SO 4 using phenolphthalein and methyl orange indicators. Ca(OH) 2 + H 2 SO CaSO 4 + 2H 2 O 2CaCO 3 + H 2 SO Ca(HCO 3 ) 2 + CaSO 4 Ca(HCO 3 ) 2 + H2SO CaSO 4 + 2CO 2 + 2H 2 O REAGENTS: (i) Sulphuric acid 1N: Place 28ml conc. H 2 SO 4 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.H 2 SO 4 (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 H 2 SO 4 = 1.0mg CaCO 3 (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. (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. Prepared By: Sandeep Siwach 21 Approved By: Dr. Arabinda Sharma

22 CALCULATIONS: PHENOLPHTHALEIN ALKALINITY (P) SAMPLE INITIAL READING FINAL READING VOLUME OF H 2 SO 4 USED METHYL ORANGE ALKALINITY (M) SAMPLE INITIAL READING FINAL READING VOLUME OF H 2 SO 4 USED If the sulphuric acid used for titration is exactly 0.02 N, Phenolphthalein alkalinity (as CaCO 3 ) mg/l (P) Phenolphthalein Alkalinity as (CaCO 3 ) mg/l = (T) Total Alkalinity as (CaCO 3 ) mg/l = Prepared By: Sandeep Siwach 22 Approved By: Dr. Arabinda Sharma

23 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- Bicarbonatealkalinity alkalinity alkalinity as Ca CO 3 as CaCO 3 as CaCO 3 P = 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). Prepared By: Sandeep Siwach 23 Approved By: Dr. Arabinda Sharma

24 EXPERIMENT NO:-12 OBJECT: To determine the Total Solids, Suspended Solids and Total Dissolved Solids of a given sewage sample 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 (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. Prepared By: Sandeep Siwach 24 Approved By: Dr. Arabinda Sharma

25 CALCULATION: Total Solids Sample Volume = 50 ml Mass of empty petriplate (A) =.. gm Mass of empty petriplate + Residue =.. gm (Y) Concentration = (B-A) = =.. gm Total Solids (mg/l) = Suspended Solids Mass of filter paper (C) =.. gm Mass of filter paper + Residue (D) =. gm (X) Concentration = (D-C) = =. gm Total Solids (mg/l) = Total Dissolved Solids = (Y-X) = Total Solid-Suspended Solid Prepared By: Sandeep Siwach 25 Approved By: Dr. Arabinda Sharma

26 EXPERIMENT NO:-12 OBJECT: To determine volatile and fixed solids in a sewage sample. 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. (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 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: Source Sample details Volume Type of Solids Weight of empty Beaker Weight of with Residue Weight of mg/l Residue Total solids Volatile solids Fixed solids Prepared By: Sandeep Siwach 26 Approved By: Dr. Arabinda Sharma

27 EXPERIMENT NO:-14 OBJECT: To determine the Oil and Grease in sewage sample. 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 (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. Prepared By: Sandeep Siwach 27 Approved By: Dr. Arabinda Sharma

28 EXPERIMENT NO:-15 OBJECT: To determine Chloride Concentration in a sewage sample. SILVER NITRATE METHOD: 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. AgNO 3 + Cl AgCl + 2KNO 3 2AgNO 3 + K 2 CrO Ag 2 CrO 4 + 2KNO 3 APPARATUS: Burette with stand Pipette Measuring Cylinder (100ml) Two Conical Flasks N/35.5 AgNO 3 Solution (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, AgNO 3 in distilled water and make up to 1000ml in a volumetric flask. Standardize it against N sodium chloride solutions 1.0ml of exactly N AgNO 3 = 1.0mg Cl (ii) Potassium Chromate Indicator Solution: Dissolve 25gm potassium chromate (K 2 CrO 4) 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. (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. Prepared By: Sandeep Siwach 28 Approved By: Dr. Arabinda Sharma

29 (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 = Normality of AgNO 3 =N/35.45 Chloride Conc. CaCO 3 = Sample Blank (Dist.Water) INITIAL READING FINAL READING VOLUME USED OF AgNO 3 Sample Sewage Sample INITIAL READING FINAL READING VOLUME USED OF AgNO 3 \ Prepared By: Sandeep Siwach 29 Approved By: Dr. Arabinda Sharma

30 EXPERIMENT NO:-16 OBJECT: To determine Sulphate Concentration in a sewage sample. 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 BaSO 4. BaCl 2 + SO BaSO 4 + 2Cl - REAGENTS: (i) Methyl Red Indicator: Dissolve 5.0gm methyl orange in 1.0 litre of distilled water. (ii) Hydrochloric Acid, (iii) Barium Chloride 5%, Dissolve 25gm barium chloride dihydrate BaCl 2.2H 2 O in 500ml distilled water. (If any turbidity appears on standing reject the solution). (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 with HCl using methyl red indicator (to orange colour). Then add additional 2ml, HCl. The samples are acidified to eliminate the precipitation of BaCO 3 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 C for atleast 30 minutes. (vi) Dry the filter paper and weigh. CALCULATION: mg/l sulphate as SO 4 2- = Prepared By: Sandeep Siwach 30 Approved By: Dr. Arabinda Sharma

31 EXPERIMENT NO:-17 OBJECT: To determine B.O.D. of a given sewage sample. 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) (ii) (iii) (iv) Phosphate buffer Magnesium sulphate solution Calcium chloride solution 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 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. Prepared By: Sandeep Siwach 31 Approved By: Dr. Arabinda Sharma

32 Mixture as (DO₁) Blank (DO ь ) CALCULATIONS: BOD mg/l = [(DO ь - DO₁) 100%) (DO ь - DO ѕ )] OBSERVATIONS: Sample details Source % mixture DO ѕ DO ь DO₁ BOD mg/l Prepared By: Sandeep Siwach 32 Approved By: Dr. Arabinda Sharma

33 EXPERIMENT NO:-18 OBJECT: To determine C.O.D. of a given sewage sample. 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 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 = (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 K 2 Cr₂O₇ Amount of K 2 Cr₂O₇ Added Normality of FeSO₄ (NH₄)₂ SO₄ ml of FeSO₄ (NH₄)₂ SO₄ Used COD mg/l Prepared By: Sandeep Siwach 33 Approved By: Dr. Arabinda Sharma

34 EXPERIMENT NO:-19 OBJECT: To determine T.O.C. of a given sewage sample. T.O.C. test is applicable to small amount of organic matter. The organic matter when mixed with acid produces CO 2 equivalent to its amount. APPARATUS: Carbonaceous Analyzer Furnace The TOC test consists of acidification of the waste water sample to convert inorganic carbon to CO 2 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 CO 2 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. Prepared By: Sandeep Siwach 34 Approved By: Dr. Arabinda Sharma

35 EXPERIMENT NO:-20 OBJECT: To determine Fecal Count of a given sewage sample. The method 1.2 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 g D-Mannitol 5.0 g Sodium chloride, NaCl g Sodium lauryl sulfate 0.2 g Sodium desoxycholate g Bromeresol purple g Phenol red 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. 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). Prepared By: Sandeep Siwach 35 Approved By: Dr. Arabinda Sharma

36 EXPERIMENT NO:-21 OBJECT: Microscopic studies of a sewage sample. 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 (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. Prepared By: Sandeep Siwach 36 Approved By: Dr. Arabinda Sharma