REPORTERS:GROUP G -G

AGA, JAMAICAGARCI A , ISABEL LARA PAULA

LAPITAN, LOREN JAMESMANI POL, MARK GLENN

PANCHO, FARLASHRECINTO, MARGARETH ROSE

Chemical Oxygen Demand (COD) Analysis

PRINCIPLESOBJECTIVESEQUATION

Introduction

Raw Sugar Factory Analysis

Regular Analysis

Fiber Determination

Hydrometer Brix

Moisture Determination

Pol Determination

Chemical Oxygen Demand

High Performance

Liquid Chromatograph

y

Gas Chromatograph

y

Special Analysis

Sugar Color Turbidity

Raw Sugar Factory Analysis

•In the case of the experiment, it is an analysis for waste water sample

•Can be organic or inorganic compounds

Analysis of what?

•Organic matter consume oxygen for life synthesis

•Some inorganic matter, such as ammonia and nitrite, can consume oxygen through oxidation

Why Oxygen?

•An analysis that measures the amount of oxygen consumed by the organic and inorganic compounds in the waste water sample

•Expressed in milligrams per liter (mass of oxygen consumed per liter solution)

General Definition

•Useful in waste water treatment

•COD measurements are used as restrictions for industries before returning the waste water back to the environment

Waste Water

•Use COD measurements as standards for waste management

Government

•Helps lessen pollution

Environment

Results are available at a short time

Requires fewer steps in the preparation of the sample

Oxidizes a wide range of chemical compounds

Standardization is easier

COD Analysis

Results may take some time to obtain

Preparation of samples are more difficult

Oxidation is limited due to biologically resistant matters

Standardization may prove more difficult due to the resistance of some compound to oxidation.

BOD Analysis

Chemical Oxygen Demand (COD) Analysis

· What is COD Analysis?

· What is/are the importance of COD Analysis?

· Biochemical Oxygen Demand (BOD) Analysis VS Chemical Oxygen Demand (COD) Analysis

· ObjectivesTo understand the chemical properties involved in the COD AnalysisTo determine the COD concentration of the waste water sample

To know the advantages and disadvantages using COD Analysis

Chemical Oxygen Demand (COD) Analysis

· General Formula

COD concentrati

on

• mL FAS used for blank

A

• mL FAS used for sample

B

• Molarity of FAS

M

• Milliequivalent weight of oxygen X 1000mL/L

8000

REAGENTSEQUIPMENT

FLOW CHART

Materials and Methods

Reagents

6.13g of K2Cr2O7

• Previously dried

Dissolve in distilled water

Dilute to 500mL

· standard K2Cr2O7

· prepared Ag2SO4-H2SO4 solution

Ag2SO4 crystals

Dissolve in 98v/v% H2SO4

• At a rate of 5.5g of Ag2SO4 per kg of

H2SO4

· Ferrous indicator

Dissolve and dilute to 50mL in distilled water

0.742g 110-phenanthrolin

e monohydrate

348 mg FeSO4·7H2O

· standard ferrous ammonium sulfate (FAS)

46.5 g of Fe(NH4)2(SO4)2·6H2

O

Dissolve in distilled water

Add 10ml of 98v/v% H2SO4

Cool

Dilute to 500mL

12mL of standard K2Cr2O7 solution

Add 15ml of prepared Ag2SO4-

H2SO4 solution

Dilute to 50ml with distilled water

Add 2-3 drops of ferrous indicator

Titrate with prepared FAS

solution

Equipment· reflux flask

· heat source

· condenser

· iron stand w/ iron clip

· pipette

· aspirator

· graduated cylinder

· rubber tube

· stirring rod

· beaker

· Erlenmeyer flask

· analytical balance

Set up

25mL of sample

•Contained in reflux flask

Add the ff:

•Boiling chips

•2.5ml Ag2SO

4-H2SO4 solution

•25ml standard K2Cr2O

7

Mix thoroughly

•Attach to condenser

•Cool

Add 10m

l H2SO4

•Mix thoroughly

•Cool

Proceed to

refluxing

•Reflux for 1hr while heating

Cool

•to room temperature

Add the

ferrous

indicator

•2-3 drops

Titrate with standard FAS

solution

•Until the first permanent color of blue green.

25mL of

distilled

water

•Contained in reflux flask

Add the ff:

•Boiling chips

•2.5ml Ag2SO

4-H2SO4 solution

•25ml standard K2Cr2O

7

Mix thoroughly

•Attach to condenser

•Cool

Add 10ml H2SO

4

•Mix thoroughly

•Cool

Proceed to

refluxing

•Reflux for 1hr while heating

Methods

· two trials are done

· a blank solution was also prepared

Cool

•to room temperature

Add the

ferrous

indicator

•2-3 drops

Titrate with standard FAS

solution

•Until the first permanent color of blue green.

DATA TABLESDISCUSSIONS

Results and Discussions

Amount of FAS solution used

BlankWastewater

Trial 1

Trial 2

Final reading, ml 22.3 19.3 16.4

Initial reading, ml 3 13 12

Total amount, ml 19.3 6.3 4.4

Amount of FAS solution used

Trial 1 Trial 2

Amount of COD, mg/L 959.712 1099.9776

Data Tables

Table 1.1

Standardization of 500ml FAS solution using K2Cr2O7

K2Cr2O7

Final reading, ml 50

Initial reading, ml 37

Total amount, ml 13.00

Table 1.2

Titration of the water samples (150mL each) using the standardized ferrous ammonium sulfate (FAS).

Table 1.3

Amount of COD concentration analyzed in wastewater samples

Discussions

· different methods

Open Reflux Method

• Wide range of waste matter

• Large amount of sample size

Closed Reflux

Method• Done under

principles of titrimetry and colorimetry

• Samples are uniform and homogeneous

• More economical

· importance of standardization

For comparison with the results

obtained from the experiment

An excess in potassium

dichromate must be added for all

organic matter to be oxidized

· standardization of FAS solution

Molarity of FAS solution,

ml

K2Cr2O7  undergoes  six-reduction reaction

The calculated molarity of FAS solution was 0.0065M

0.0065M FAS solution was used in the computations for COD analysis

· sample

Taken from the washings of dishes in the CEAT Lounge

Cafeteria· reagents

•Amount added is equivalent to the amount of potassium dichromate added

Ferrous ammonium

sulfate (FAS)

•Catalyst for oxidation

•reduce pH of the solution

Sulfuric acid solution

•Used as strong oxidizing agent to ensure transfer of oxygen atoms

•Most effective in oxidizing organic compound in water the other oxidizing agents

Potassium dichromate

· results

•4.5067 mg O2/L and 5.1653 mg O2/L

•Relatively low compared to the actual COD analysis in industries

Amount of COD

•30.4811% and 27.6700%

•Based from the theoretical amount of FAS solution required to oxidize K2Cr2O7

in the blank sample

% error· limitations and advantages of COD Analysis

Cannot differentiate organic from inorganic matter

Determination for N-value cannot be accurately known

Limitations

Procedure is simple

Gives reproducible results

Can be performed at a shorter time than BOD analysis

Advantages

· sources of errors

•Full of dusts

Working place

•Shortage of equipment

•Unclean equipment

Equipment

•Imprecise in measurements

•Subjective observation of color change

Performer of the

experiment

SUMMARYCONCLUSION

RECOMMENDATION

Summary and Conclusion

• Full of dusts

Working place

• Unclean• Some are not in good

condition

Equipment

• Imprecise measurements• Mistake in calculations• Improper handling of

apparatus

Human error

Summary

· COD Analysis

• Test for wastewater quality by indirectly measuring the oxygen requirement of the sample

Principle

• Open Reflux Method• Closed Reflux Method

Types

• Cannot differentiate organic from inorganic matter

Limitations

• Can be easily done• Results are reproducible• Results can be obtain in a short span of time

Advantages

· results

• 959.712mg/L• 1099.9776mg/L

Chemical oxygen demand per liter of water sample

· sources of errors

Conclusion

The obtained amount of COD in the analysis of the wastewater sample is very alarming since it is larger relative to the amount of COD obtained in industrial plants.

However, due to the sources of error, the obtained results are unreliable thus, the conclusions made are uncertain.

Recommendation

• Must always be clean

Working place

• Must always be clean• Must be in good condition

Equipment

• Commercially available reagents are recommended to lessen errors derived from lab-prepared ones.

Reagents

• All glasswares/apparatus must always be rinsed with distilled water to remove undesired substances.

Distilled water

• Half-drop technique must be followed

Titration

• Comparison with the results obtained using KHP as reference standard is recommended to verify results

Potassium hydrogen phthalate (KHP)

THANK YOU!! ! !

End