Measure COD of WasteWater Using Closed Reflux Method

Apparatus

1. Digestion vessels (vial)

2. COD Reactor

3. Spectrophotometer

4. Premixed Reagentsin Digestion Vessel (vials)

5. K2g2O₇

6. Concentrated H2SO₄

7. HgSO₄

8. Ag₂SO₄

Procedure:

1. Place Approximately 500ml Of Sample In a clean blender bowl and homogenizze at high speed for two minutes. blending the sample ensures a auniforum distribution of suspended solids and thus improves the accuracy of test results.

2. Pre heat the COD reaction to Iso c

3. Carefully remove the cap of COD digestion Reagent vial.

4. While holding The vial at a 45 degree angle carefully pipet 2 ml sample into the vial.

5. Replace and tighten the cap.

6. Holding the vial by the cap in an empty sink, gently invert several times to mix the contents they will become very hot during mixing.

7. Place the vial in prehented COD reacton.

8. Prepare a reagent blank by repeating step 3 through 6, substituting2 ml of distilled water in place of sample.

9. Incubate the vial for two hours at size.

10. Turn off the reaction off and alllow the vials to cool to 120 degree and less. invert each vial several times while still warm place vial in a cooling reach and allow them to room temp.

11. Measure the COD using spetrcophotamctrum method.