Water Quality Project

Project 2

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United Arab Emirates University

College of Engineering

Chemical & Petroleum Engineering Department

* Group Number: (1)

* Members: * ID Number :

* Instructor:

Section: ( )

Water Quality Parameters

**Contents :

Title Page

1 Cover Page 1

2 Index 2

3 Abstract 3

4 Experimental Procedure 4-7

5 Result and Discussions 8-10

6 Conclusion 11-12

7 Recommendations 13

8 Reference 14

9 Appendix A: (Sample Caculation) 15-18

10 Appendix B: (Original Data) 19-20

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** Abstract:

Water is one of the most important elements in this planet. It

covers 70.9% of the Earth. There are several types of water, these

types are determined by knowing some water properties called

parameters such as pH, total dissolved solids, alkalinity, and

hardness. In this project, we aim to know the quality of water by

determining these parameters for four different water samples (sea,

mineral, tap and distilled). This experiment has been divided into

three parts. Starting with total dissolved solids (TDS), weight solid

was formed. Then, the total alkalinity of a water sample has been

found by titration using a strong acid (H2SO4). Finally , the total

hardness has been measured using the (Na2(EDTA)) solution. At the

end, the result shown that the highest total alkalinity was found in

the sea water, but it was the smallest in the distilled water. Also the

highest total hardness was found in the sea water, while the

smallest was found in the distilled water.

** Experimental Procedure:

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http://en.wikipedia.org/wiki/Earth

Measurement of the Total Distilled Water (TDS) :-

* Equipments:-

- 4 types of water (sea, mineral, tap and distilled).

- 50-ml beaker.

- Graduated cylinder.

- Heating Plate.

- Balance.

* Experiment Procedure:-

- A dry 50-ml beaker was placed on the balance to record its weight.

- A 25 ml from each sample of water (sea, mineral, tap and

distilled ) was measured by flasks and added to the dry 50-ml

beaker and its weight was recorded again.

- The 50-ml beakers were placed on a heating plate and left to dry

completely.

- Then the solid weights were measured again using the balance.

- The total dissolved solids (TDS) for each sample was then calculated (see appendix A).

Measurement of the Total Alkalinity (ANC) :-

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* Equipments:-

- 0.001 M Sulfuric acid.

- Bromcresol green indicator (this indicator becomes green at

pH=4.5).

- Burette.

- Graduated cylinder.

- 250-ml flasks.

- pH meter.

- 150-ml flasks.


Step 1: Burette preparation:

The burette was prepared by filling it to the top of the graduated

area with standard 0.001M sulfuric acid.

Step 2: Initial reading of the burette was recorded.

Step 3: Preparation of the water samples and pH

measurement:

For each sample of water we took 50 ml (except for Sea water which

was 10 ml) then they were put into a 150-ml capacity flask using a

graduated cylinder. Each flask was then labelled according to its

different type of water source. The pH of all raw water samples was

measured using the pH meter.

Step 4: Addition of the indicator:

Three drops of the Bromcresol green indicator were added into each

flasks. The samples’ colour were changed.

Step 5: Titration process:

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Each sample was then titrated with the standard 0.001 M sulfuric

acid while it was gently swirled. The titration process stopped when

the samples changed to green which indicated that the pH is 4.5.

Step 6: final reading of the burette:

The volume of the acid in the burette was recorded, and same steps

were repeated for all samples.

Step 7: Calculations:

The total alkalinity for each sample was then calculated. (See

Appendix A)

Measurement of the Total Hardness :-

* Equipments:-

- Distilled water

- Eriochrome Black T (EBT) indicator

- pH 10 buffer ( 2 ml ammonia-ammonium buffer for each

sample)

- 0.005 M Standard EDTA solution (by dissolving Na2(EDTA) in

distilled water)

- Burette

- Graduated cylinder

- 250-ml flasks and test tubes


Step 1: Addition of the buffer and the indicator to water

samples

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50 ml were taken from the 3 water samples (mineral, tap and

distilled ), but 1 ml was taken from the sea water. Then, the pH 10

buffer and the indicator (EBT) were added to the water samples. All

samples’ color was changed to purple, except for the distilled water

which was blue.

Step 2: Preparation of the burette.

The burettes were prepared by filling with 0.005 M EDTA solution and record the initial volume.

Step 3: Titration process.

The titration was begun smoothly. When the solution color changes from raspberry red to blue, the titrations were stopped and record the final volume. That was repeated again for each sample.

Step 5: Calculations.

The total hardness for each sample was then calculated (see

appendix A).

** Results and Discussion:

pH values for different samples:

Water Sample pH

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Table 1: PH values of different samples

Sea Water 8.41

Distilled Water 5.83

Tap Water 8.64

Mineral Water 7.38

Table (1) shows the values of pH. As we can see, the pH of the sea water was 8.41 and the pH of the tap water was 8.64 which were more 7, so they act as the base and they are a proton acceptor. However, the pH of the distilled water was 5.83; therefore the distilled water can acts as an acid. Finally, we can see the pH of the mineral water was 7.38 which almost neutral.

Finding the Total Dissolved Solids (TDS):

Water SampleWater

VolumemL

TDS (mg/L)ppm

Water classification

Sea Water 25 52400 SalineDistilled Water 25 14800 Saline

Tap Water 25 9600 SalineMineral Water 25 17200 Saline

As we can see, table (2) shows the total dissolved solids of different samples of water. The TDS of all samples was above 5000 mg/L however the sea water was the higher one; therefore we can classify them as saline water which can be used for crop production, irrigation and also in some industries.

Finding the Total Alkalinity (ANC ):

Water SampleWater Volume

mLTotal Alkalinity

mg/L

Sea Water 10 114Distilled Water 50 2

Tap Water 50 50.8Mineral Water 50 25.4

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Table 3: The Total Alkalinity of different samples

Table 2: TDS values of different samples with their classifications

Table (3) shows the total alkalinity for each water sample. All samples changed from blue to green after the titration. Sea water was the most interesting result; its alkalinity was 114 mg/L which was the largest. This is because it has large amounts of mineral salts, so it has more ability to neutralize the acids. The distilled water had the lowest alkalinity which was 2 mg/L. This indicates that distilled water has the smallest amounts of mineral salts.

Finding the Total Hardness:

Water SampleVolume of

WatermL

Hardness mg/L

Degree of Hardness

Sea Water 1 11500 Very hardDistilled Water 50 0 soft

Tap Water 50 69 softMineral Water 50 130 Hard

In Table (4) we can see the hardness of the four samples. The

hardness of the sea water is the highest. The reason is because it

contains a large quantity of calcium and magnesium cations;

therefore it was classified as very hard water. The hard water

cannot be used for anything and even for washing. The hardness of

distilled water sample was 0 mg/L which indicates that it doesn't

contains any cations that cause the hardness, so its color remains

blue. The distilled was classified as soft water because it had less

than 75 mg/L of the hardness. The tap water classified also as soft

which indicates using it in washing. Finally, the hardness for the

mineral water 130 mg/L, because it contains many elements

including sodium, potassium, calcium and magnesium. The colour of

these samples ( tap – sea – mineral ) changed from Raspberry red to

blue.

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Table 4: The total hardness of different samples

** Conclusion:

1- In this experiment, we have successfully found out the quality of four samples of water ( sea – tap – distilled – mineral ) and compare between them using the water parameter ( pH, TDS, ANC, Hardness ).

2- In the case of sea water, our results showed that it acts like a base because it has a number of pH greater than 7. Also, it considers as saline water according to the TDS parameter. In addition, sea water has the biggest ability to neutralize acid because it’s containing a large quantity of mineral salts. However, this large amount contains Mg2+ and Ca2+ which make the sea water very hard water. So, we can’t use it in washing.

3- In the case of distilled water, our results showed that it acts like an acid because its pH is less than 7. It’s also considered to be saline water because TDS was above 5000. The distilled water has neither cations nor anions, so it has the lowest

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ability to neutralize the added acid and also it classified as soft water.

4- In the case of the tap water, our result showed that it act like a base ( pH > 7 ). As the TDS is greater than 5000 so it’s considered as saline water. It has the ability to neutralize the acid because it contains ions. Also, it consider as soft water.

5- In the case of the mineral water, our result showed it’s almost neutral water because its pH is almost equal to 7. It classified as saline water (TDS > 5000). It has a big ability to neutralize the acid and it classified as hard water because it conation a large amount mineral salts.

6- As we notice, the color of the four samples of water changed before and after titration in total alkalinity and hardness phases. In ANC phase, they changed from blue to green. In hardness phase, they changed from raspberry red to blue, except the distilled water which remained blue because there are no calcium and magnesium cations.

7- There was no theoretical measurement for the water quality parameters, which indicates that there’s no percentage error to be calculated.

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** Recommendations:

- Be prepared and bring all your safety needs like the lap coats, gloves and the close shoes.

- Read the experiment before the class.

- Pay attention to your instructor to understand the experiment.

- Concentrate on what you are doing and follow the experimental procedure.

- Don’t be hasty.

- Be accurate in taking data and measurement.

- Be careful while you’re dealing with acid and base.

- Write down your observation. Like what was the color of the 4 samples of water after and before the titration.

- Be patient is required, some samples of water need time when

titration.

- For accuracy, the correct measuring equipments should be

used (i.e. the grading or the scale).

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- Work in groups, so that makes your results accurate and precise.

** References:

- Faculty Members from the Department of Chemical and Petroleum Engineering, Student laboratory Manual, 2008.

- http://en.wikipedia.org/wiki/Total_dissolved_solids

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http://en.wikipedia.org/wiki/Total_dissolved_solids

Appendix A(Samples Calculations)

Finding the Total Alkalinity:

Convert ml of acid used in the titration to moles of H2SO4:

1. Sea water: Volume of H2SO4 used in the titration = 12.4 – 1 = 11.4 ml

Number of moles of H2SO4 = (11. 4ml )( 0 .001

1L)( 1 L

103ml)= 1.14 x 10-5

2. Distilled water: Volume of H2SO4 used in the titration = 1.0 – 0 = 1 ml

Number of moles of H2SO4 = (1ml )( 0 .001

1 L)( 1L

103ml)= 1.0 x 10-6

3. Tap water: Volume of H2SO4 used in the titration = 37.8 – 12.4 = 25.4 ml

Number of moles of H2SO4 = (25 .4ml )( 0 .001mol

1L)( 1 L

103ml)= 2.54 x

10-5

4. Mineral water: Volume of H2SO4 used in the titration = 43.7 – 31.0 = 12.7 ml

Number of moles of H2SO4 = (12. 7ml )( 0 .001

1L)( 1 L

103ml)= 1.27 x 10-5

Determine the moles of CaCO3 present initially in the solution by utilizing the reaction stoichiometry:

CaCO3(aq) + H2SO4(aq) → H2O(l) + CO2(aq) + CaSO4(aq)

1 mol CaCO3 1 mol H2SO4

1) Sea water:

Number of moles of CaCO3 = 1.14 x 10-5 moles

2) Distilled Water:

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3) Tap Water:


4) Mineral Water:


Convert moles of CaCO3 into mg of CaCO3 (1 mg = 10-3 g):

1) Sea Water:

Mass of CaCO3 =

(1. 14 x 10−5mol )(100 . 09g1mol

)(1000mg1 g

)= 1.14 mg

CaCO3

2) Distilled Water:

Mass of CaCO3 = (1. 0 x10−6mol )(100 .09g

1mol)(1000mg

1 g)= 0.1 mg

CaCO33) Tap Water:

Mass of CaCO3 = (2 .54 x 10−5mol )(100 . 09g

1mol)(1000mg

1 g)= 2.54 mg

CaCO34) Mineral Water:

Mass of CaCO3 = (1. 27 x10−5mol )(100 .09 g

1mol)(1000mg

1g)= 1.27 mg

CaCO3

Use the volume of the sample titrated to find the alkalinity of each sample in mg CaCO3 per liter:

1) Sea water:

Alkalinity =

( 1 . 14mg10ml

)(1000ml1L

)= 114 mg/L

2) Distilled Water:

Alkalinity =

( 0. 1mg50ml

)(1000ml1L

)= 2 mg/L

3) Tap Water:

Alkalinity =

( 2. 54mg50ml

)(1000ml1 L

)= 50.8 mg/L

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4) Mineral Water:

Alkalinity =

( 1 . 27mg50ml

)(1000ml1L

)= 25.4 mg/L

Finding the Total Dissolved Solids (TDS):

Convert ml of Na2-EDTA solution used in the titration to moles of Na2-EDTA:

1) Sea Water:

a. Volume of Na2-EDTA used in the titration = 42.8 – 19.9 = 22.9 ml

b. Number of moles of Na2-EDTA = (22 .9ml )( 0 .005mol

1 L)( 1L

103ml)= 1.145 x

10-4

2) Distilled Water:

a. Volume of Na2-EDTA used in the titration = 0.0 ml

b. Number of moles of Na2-EDTA = 0.0 moles

3) Tap Water:

a. Volume of Na2-EDTA used in the titration = 6.9 – 0 = ml

b. Number of moles of Na2-EDTA = (6 . 9ml )( 0 . 005mol

1 L)( 1 L

103ml)= 3.45 x

10-5

4) Mineral Water:

a. Volume of Na2-EDTA used in the titration = 19.9 – 6.9 = 13 ml

b. Number of moles of Na2-EDTA = (13ml )( 0 .005mol

1L)( 1 L

103ml)= 6.5 x

10-5

Determine the moles of Ca2+ and Mg2+ present initially in the solution by utilizing the reaction stoichiometry and find the moles of CaCO3 :

[EDTA-H2]2- + M2+ (Ca2+ or Mg2+) [EDTA-M]2- + 2H

1 mole M2+ (Ca2+ or Mg2+) 1 mole Na2-EDTA

1) Sea Water:

Number of moles of (Ca2+ or Mg2+) = 1.145 x 10-4 moles


2) Distilled Water:

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Number of moles of (Ca2+ or Mg2+) = 0 moles

Number of moles of CaCO3 = 0 moles

3) Tap Water:



4) Mineral Water:



Convert moles of CaCO3 into mg of CaCO3 (1 mg = 10-3 g):

1) Sea Water:

Mass of CaCO3 =

(1. 145 x10−4mol )(100 . 09g1mol

)(1000mg1 g

)= 11.5 mg CaCO3

2) Distilled Water:

Mass of CaCO3 = = 0.0 mg CaCO3

3) Tap Water:

Mass of CaCO3 =

(3 . 45 x10−5mol )(100 . 09 g1mol

)(1000mg1g

)= 3.45 mg CaCO3

4) Mineral Water:

Mass of CaCO3 =

(6 . 5x 10−5mol )(100 .09g1mol

)(1000mg1 g

)= 6.5 mg CaCO3

Use the volume of the sample titrated to find the total hardness of each sample in mg CaCO3 per liter:

1) Sea Water:

Hardness = (11.5mg

1ml)(1000ml

1L)= 11500 mg/L

2) Distilled Water:

Hardness = ( 0mg50ml

)(1000ml1L

)= 0 mg/L

3) Tap Water:

Hardness = ( 3. 45mg50ml

)(1000ml1 L

)= 69 mg/L

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4) Mineral Water:

Hardness = ( 6 .5mg50ml

)(1000ml1 L

)= 130 mg/L

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Water Quality Project

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