After the coagulation and flocculation process, the wastewater is treated up to that parameter (COD, BOD, etc.) which are acceptable as per government criteria to dump into water bodies instead of directly dumping and also to overcome problems like toxicity and health hazard posed by inorganic coagulants, production of large amount of toxic sludge, ineffectiveness in removing heavy metals and emerging contaminants, increase in effluent color, inefficient pollutant removal using natural coagulants, and complexity of scaling up procedure are presented

1. Study of Coagulation and
Flocculation Process
FOR WASTEWATER
Guided By:-
Dr. Nimish Shah
Submitted By:-
Deep Kotak (17BCH024)
Shikruti Mardaraj (17BCH049)

2. Wastewater
Fig. Common Effluent Treatment Plant (CETP)
Vatva industryFig. Industrial wastewater

3. Coagulation Flocculation
It is a chemical process It is a physical process
The coagulant is often a salt and breaks down to
release charges
The flocculant is often a polymer which induces
the settling of particles and eventually grows
into large flake
No need for techniques like mixing Uses techniques such as mixing since this is a
physical process
Coagulation and Flocculation

4. Factors that affect coagulation and
flocculation Process
• Type of rapid mix device
• Velocity gradients applied during
flocculation stage
• Flocculator retention time
• Type of stirring device used
• Flocculator geometry
• Type of coagulant used
• Coagulant dosage
• Final pH
• Coagulant feed concentration
• Type and dosage of chemical additives
other than primary coagulant (e.g.
polymers)
• Sequence of chemical addition and
time lag between dosing points
• Intensity and duration of mixing at
rapid mix stage

5. STABILITY AND STRUCTURE OF
COLLOIDS
Fig. Electrical Double Layer of Colloidal Particles Fig. Particle Interaction Energy

6. MECHANISMS INVOLVED IN
COAGULATION
To destabilize a colloidal system, coagulant i.e. a hydrolyzing electrolyte like metal
salts or long chain synthetic/organic polymers are added. They undergo one of the
following four mechanism to destabilize the system: -
• Double-layer compression.
• Adsorption and charge neutralization.
• Entrapment of particles in precipitate.
• Adsorption and bridging between particles.

7. Double Layer Compression Charge Neutralization and
Adsorption

8. Entrapment of particles in
precipitate.
Bridging between particles and
Adsorption

9. Methods that are used to control and
evaluate the coagulation process are:
• Jar testing
• Electrophoretic mobility studies
• Streaming current detector
• Colloidal titration techniques
• Conductivity measurements

10. JAR TESTS ELECROPHORETIC MOBILITY
Fig. Zeta Potential vs DosageFig. Effect of alum dosage on removal of COD, TP, TSS

11. STREAMING CURRENT
DETECTOR
COLLOIDAL TITRATION
Fig. Streaming current vs Polymer coagulant dosage Fig. Colloidal titration for raw municipal water

12. CONDUCTIVITY MEASUREMENT
Fig. Conductivity vs Alum dosage

13. OPTIMUM DOSAGE OF COAGULANT
For 12g/100ml
Sr. No Volume of coagulant added (ml) Conductivity (mS)
1. 0 4.92
2. 0.2 4.91
3. 0.4 4.89
4. 0.6 4.85
5. 0.8 4.89
6. 1.0 4.87
7. 1.2 4.97
8. 1.4 5.37
9. 1.6 6.32
10. 1.8 7.6
Table. Volume of coagulant added (in ml) and conductivity (mS).
Inital Conductivity
of sample
Optimum Dosage
4.4
4.6
4.8
5
5.2
5.4
5.6
5.8
6
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
0 0.5 1 1.5 2
Conductivity(mS)
Volume of coagulant added (ml)
Optimum Coagulant Dosage (for 12g/100ml)
Fig. Conductivity meter
Fig. conductivity vs vol. of coagulant

14. ANALYSIS OF WASTEWATER SAMPLE
parameters to be checked
Physical properties and
other impact
parameters
Solids Organics
pH TS BOD
Temperature TDS COD
Colour TSS TOC
Turbidity TVS Oil and Grease
Odour TFS
Alkalinity
Nitrogen and phosphors
Nutrients
• Water sample quality
• Process equipment
• Aim of the treatment
SELECTION OF COAGULANTS

15. QUALITY ANALYSIS OF WASTEWATER
SAMPLE (ODHAV)
MEASUREMENT OF COD (OPEN REFLUX)
Reagents Used: Sulphuric acid reagent, Potassium dichromate
solution (0.04167M), Ferroin indicator, Ferrous ammonium
sulphate solution (0.25M), Mercuric Sulphate.
COD as O2 mg/L =
B−S ∗M∗8000
ml of sample used for titration
where B – Volume of FAS used for blank titration
S – Volume of FAS used for sample titration
M – Molarity of FAS used

16. Fig. sample before titration Fig. After titration with FASFig. samples after heating of 2 hr. at 150 ℃

17. Sr
No
.
Sample Volume of
FAS used
COD (O2
mg/L)
1 Blank 8.7 0
2 Wastewater sample
(Odhav)
5.7 100
Treated samples
3 with 0.2ml coagulant 6.3 80
4 with 0.6ml coagulant 6.5 73.33
5 with 1.0ml coagulant 6.1 86.67
6 with 1.4ml coagulant 6 90
7 with 1.8ml coagulant 5.8 96.67
For comparison purposes
8 Wastewater sample
(Narol)
3.2 183.33 The treated sample (0.072g of lime) has the lowest COD among all the
other treated samples
Table. COD of treated and untreated samples (OR).
0
20
40
60
80
100
120
0 0.0024 0.0072 0.012 0.0168 0.0216
COD(O2mg/L)
Coagulant dosage (in g)
COD vs Dosage

18. Reagents Used: Sulphuric acid reagent, Potassium dichromate
digestion solution (0.12M), Ferroin indicator, Ferrous
ammonium sulphate solution (0.10M).
COD as O2 mg/L = B−S ∗M∗8000
ml of sample used for titration
× dilution factor
where B – Volume of FAS used for blank titration
S – Volume of FAS used for sample titration
M – Molarity of FAS used
Dilution factor – (Final volume/ Initial volume) = 101
MEASUREMENT OF COD (CLOSED REFLUX
TITREMETRIC METHOD)

19. Fig. Cultural tubes of different sample (CR) Fig. Before titration Fig. After titration with FAS

20. Sr
No.
Sample Volume of
FAS used
COD (O2
mg/L)
COD*Dilu
tion factor
1 Blank 1.6 0 0
2 Wastewater sample
(Odhav)
1 76.8 7680
Treated samples
3 with 0.2ml coagulant 1.4 25.6 2560
4 with 0.6ml coagulant 1.5 12.8 1280
5 with 1.0ml coagulant 1.3 38.4 3840
6 with 1.4ml coagulant 1.2 51.2 5120
7 with 1.8ml coagulant 1.1 64 6400
For comparison purposes
8 Wastewater sample
(Narol)
0.8 102.4 10240
The treated sample 0.6 ml of 0.012g/ml of lime has the lowest COD among all the
other treated samples.
Table. COD of treated and untreated samples (CRTM).
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0 0.0024 0.0072 0.012 0.0168 0.0216
COD(O2mg/L)
Coagulant dosage (in g)
COD vs Dosage

21. TURBIDITY
Sr No. Sample Turbidity (in NTU)
1 Blank 0
2 Wastewater sample (Odhav) 9
Treated Sample
3 with 0.2ml coagulant 4
4 with 0.6ml coagulant 1
5 with 1.0ml coagulant 0
6 with 1.4ml coagulant 2
7 with 1.8ml coagulant 8
For comparison purposes
8 Wastewater Sample (Narol) 9
.Turbidity of wastewater treated with 0.12g of lime is the least. The optimum dosage is the second least.
Table. Turbidity of treated and untreated samples
Fig. Turbidity meter
0
1
2
3
4
5
6
7
8
9
10
0 0.0024 0.0072 0.012 0.0168 0.0216
Turbidity
Coagulant dosage (in g)
Turbidity vs Dosage

22. pH
Sr No. Sample pH
1 Blank 7.02
2 Wastewater sample (Odhav) 10.10
Treated Sample
3 with 0.2ml coagulant 10.30
4 with 0.6ml coagulant 10.90
5 with 1.0ml coagulant 11.14
6 with 1.4ml coagulant 12.55
7 with 1.8ml coagulant 13.64
For comparison purposes
8 Wastewater sample (Narol) 9.86
• For pH measurement, digital pH meter is used. The pH probe is
dipped into each sample and the reading is noted down.
• The pH level is not within the acceptable range for any of the
treated sample.
Table. pH of treated and untreated samples
Fig. pH meter
0
2
4
6
8
10
12
14
16
0 0.0024 0.0072 0.012 0.0168 0.0216
pH
Coagulant dosage (in g)
pH vs Dosage

23. TOTAL DISSOLVED SOLIDS (TDS)
Sr No. Sample TDS (in ppm)
1 Blank 2
2 Wastewater sample (Odhav) 2050
Treated Sample
3 with 0.2ml coagulant 2050
4 with 0.6ml coagulant 1990
5 with 1.0ml coagulant 1960
6 with 1.4ml coagulant 2040
7 with 1.8ml coagulant 2800
For comparison purposes
8 Wastewater sample (Narol) 2840
The TDS of sample treated with 0.12g of lime is less when compared to others. The TDS
level at the optimum dosage is the more than that of 0.12g of lime but less as compared to
others.
Table. TDS of treated and untreated samples.
0
500
1000
1500
2000
2500
3000
0 0.0024 0.0072 0.012 0.0168 0.0216
TDS(inppm)
Coagulant dosage (in g)
TDS vs Dosage

24. Standards

25. CONCLUSION
0.6ml of 12g/100ml lime (0.072g of lime)
Sr No. Parameters values
1 COD 73.33 O2 mg/L
2 pH 10.90
3 Turbidity 1 Ntu
4 Total dissolved solids 1990
At 0.6ml of coagulant dosage (0.072g of lime), COD of the sample after coagulation is minimum and
parameters such as turbidity and TDS are within acceptable limit of Indian standards i.e. 1 NTU and
500 mg/L. The value of pH is not within acceptable limits. Since COD is our top priority, 0.6ml of
coagulant dosage can be concluded to be the optimum dosage.
Table. Values of different parameters for 0.072g of lime treated sample

26. We had nothing Today we have everything
Fig. only samples & few chemicals without
any glassware
Fig. All chemicals with glassware