INTRODUCTION
Jar testing is a pilot-scale test of the treatment chemicals used in a particular water plant. It
simulates the coagulation/flocculation process in a water treatment plant and helps operators
determine if they are using the right amount of treatment chemicals, and, thus, improves the
plants performance
OBJECTIVE
1. To determine optimum dosage of coagulant.
2. To measure the water quality parameter such as turbidity, pH and color before and after
the Jar Test.
PROBLEM STATEMENT
Surface waters, containing colloidal particles, are normally treated by coagulation-flocculation
followed by clarification. As a group you will be given two (2) types of coagulants. You are
required to carry out jar test on the water sample given using the appropriate apparatus available
in the laboratory.
APPARATUS
The apparatus for Jar Test Experiment are Turbidity meter, pH meter Photospectrometer, Beaker,
Measuring Cylinder, Pipette, Coagulant Solution, Stirring Machine.
Stirring machine pH meter
Turbidity meter
PROCEDURE
- The turbidity and pH of the water sample have been determined, it is need to used
turbidity and pH meter .The data need to take 3 reading and it taken from the initial
reading.
- The 6 beakers filled with 500ml each and mark it
- Prepared 2,4,6,8,10,12ml of coagulant solution and poured into small measuring cylinder.
- The beaker was placed on the stirring machine and lower the stirrers properly.
- For the first stage, Stirrer speed was set to 140rpm and stirred for 3 minutes and it
repeated for 40rpm for 7 minutes
- The stirrer was stopped and left unstirred for 15 minutes for sedimentation process
- Small beaker was taken and it is fill with small quantity of water sample that was
extracted from each beaker
- Turbidity and pH from extracted samples was determined by turbidity meter and pH
meter. The reading was taken for 3 times
DATA ACQUISITION
Initial Reading
Coagulant Turbidity (NTU) pH Level Temperature Color
(C)
Al2(SO4)3 55.3 6.80 30.5 423
55.0 6.92 30.5 411
52.7 6.79 30.5 402
Average 54.3 6.84 30.5 412
Coagulant Turbidity (NTU) pH Level Temperature Color
(C)
Fe2(SO4)3 338 7.21 30.4 836
352 7.11 30.4 821
352 7.10 30.4 809
Average 347.3 7.14 30.4 822
Final Reading
Coagulant Type: Al2(SO4)3
Beaker Turbidity (NTU) pH Level Temperature (C) Color
1 34.0 6.96 30.7 250
32.6 6.67 30.7 252
32.9 6.49 30.7 252
Average 33.2 6.70 30.7 251.3
2 33.5 6.17 30.6 237
31.6 5.87 30.6 238
31.4 5.56 30.6 238
Average 32.2 5.90 30.6 237.7
3 31.2 5.49 30.7 218
30.8 5.44 30.7 218
32.0 5.22 30.7 218
Average 31.3 5.38 30.7 218
4 22.3 4.89 30.7 159
21.9 4.85 30.7 163
21.5 4.14 30.7 161
Average 21.9 4.63 30.7 161
5 15.3 3.60 30.6 115
17.4 3.54 30.6 116
17.5 3.52 30.6 116
Average 16.73 3.55 30.6 115.7
6 10.1 4.56 30.6 71
11.1 4.36 30.6 72
10.2 4.27 30.6 70
Average 10.7 4.40 30.6 71
Final Reading
Coagulant Type: Fe2(SO4)3
Beaker Turbidity (NTU) pH Level Temperature (C) Color
1 11.2 7.04 30.9 69
10.4 6.98 30.9 70
10.7 6.88 30.9 68
Average 10.8 6.97 30.9 69
2 8.35 7.06 30.8 43
8.45 6.92 30.8 44
7.76 6.85 30.8 44
Average 8.19 6.94 30.8 43.67
3 10.3 6.17 30.8 75
10.5 6.19 30.8 74
9.97 6.20 30.8 74
Average 10.06 6.19 30.8 74.33
4 46.2 6.00 31.2 399
45.0 5.88 31.2 396
46.3 5.71 31.2 396
Average 45.83 5.86 31.2 397
5 16.8 5.45 31.1 175
17.0 5.34 31.1 175
16.8 5.20 31.1 176
Average 16.87 5.33 31.1 175.33
6 52.0 4.15 31.2 492
55.8 4.09 31.2 492
55.1 4.06 31.2 493
Average 54.3 4.10 31.2 492.33
Change in Turbidity, T
Coagulant Type: Al2(SO4)3
Beaker Initial Turbidity Final Turbidity Change in Turbidity,
(NTU) (NTU) T (NTU)
1 54.3 33.2 21.1
2 54.3 32.2 22.1
3 54.3 31.3 23
4 54.3 21.9 32.4
5 54.3 16.7 37.6
6 54.3 10.7 43.6
Coagulant Type: Fe2(SO4)3
Beaker Initial Turbidity Final Turbidity Change in Turbidity,
(NTU) (NTU) T (NTU)
1 347.3 10.8 336.5
2 347.3 8.19 339.11
3 347.3 10.6 336.7
4 347.3 45.83 301.47
5 347.3 16.87 330.43
6 347.3 54.3 293
Concentration of Coagulant
Concentration of Alum = 10g/L
Concentration of Ferum = 1g/L
Coagulant Type: Al2(SO4)3
Beaker 1 2 3 4 5 6
Vol. of Water 500 500 500 500 500 500
Sample (mL)
Vol. of 2 4 6 8 10 12
Coagulant
(mL)
Mass of 0.02 0.04 0.06 0.08 0.10 0.12
Coagulant (g)
Concentration 40 80 120 160 200 240
of Coagulant
(mg/L)
Coagulant Type: Fe2(SO4)3
Beaker 1 2 3 4 5 6
Vol. of Water 500 500 500 500 500 500
Sample (mL)
Vol. of 2 4 6 8 10 12
Coagulant
(mL)
Mass of 0.002 0.004 0.006 0.008 0.01 0.012
Coagulant (g)
Concentration 4 8 12 16 20 24
of Coagulant
(mg/L)
Calculation
Mass of coagulant Al2(SO4)3 = (2ml / 1000ml) x 10g
= 0.02 g
Volume of Concentration Al2(SO4)3 = 0.02g / 500ml
= 40mg / l
Graph of Alum
50
45
40
Change in Turbidity, T
35
30
(NTU)
25
20
15
10
5
0
0 50 100 150 200 250 300
Concentration of Coagulant (mg/L)
Graph of Ferum
350
340
Change in Turbidity, T
330
(NTU)
320
310
300
290
0 5 10 15 20 25 30
Concentration of Coagulant (mg/L)
