SOP for Operation and Cleaning of COD Digester

OBJECTIVE

To provide a procedure for the operation of the COD Digester.

SCOPE

This procedure applies to COD Digester at XYZ Ltd.

RESPONSIBILITY

Quality Control Chemist and above

ACCOUNTABILITY

Quality Control Head

PROCEDURE

Precaution

• Ensure that the instrument is clean and free from dust.
• Keep the instrument 1 foot away from the wall.
• Keep the instrument away from the washbasin or any water source.
• Ensure that any solvent/chemical does not fall on the aluminum block when it is hot.

• Use asbestos gloves while handling the hot tubes.
• Do not try to remove the tubes from the COD block and keep it in the tube stand.
• Do not try to remove the condenser tube when it is hot.
• Switch OFF the instrument when not in use.
• Calibrate the digital timer controller and heating sensor of the COD Digester once a year by the approved outside agency.

ALSO READ: SOP for Operation and Calibration Procedure for Polarimeter

Cleaning

• Disconnect the instrument from the electrical connection.
• Clean the instrument with a soft cloth.
• Clean the tubes as per SOP of Cleaning of Laboratory Glassware.

Operation

• Connect the instrument to the main supply. Switch on the main supply.
• The red-colored bulb will glow indicating the power supply is connected.
• The orange-colored bulb will glow indicating the heater is on.
• The orange bulb remains on until the temperature is attained and will be switched off when the desired temperature is attained.

• Adjust the required temperature and time with the help of keys given on the digital control panel.
• Press the SET key.
• The display will show SP for temperature.
• Set 150°C temperature with the help of the up and down keys.
• Again press the SET key.
• The display will show soak time.
• Set 2.0 Hours with the help of up and down keys.
• In the soak time parameter, the digits before the decimal are hours & after the decimal it is minutes. i.e, (hh: mm)
• Fill 30 ml of the content of the sample in each tube and tightly close it with the condenser tube.
• Place 30 ml filled tubes in the aluminum COD block of the COD Digester for 2 hours.
• After completing the cycle, a digital alarm for 10 seconds will be produced and the heating will get automatically stopped.
• Allow cooling at room temperature.
• Perform further analysis as per the Specification of Chemical Oxygen Demand.

ABBREVIATIONS

COD: Chemical oxygen demand

SP: Set point

°C: Degree Celsius

hh: mm

Hours: Minutes

%: Percentage

ml: Milliliter

ANNEXURES

Nil

REVISION HISTORY

Nil

ALSO READ: SOP for Operation and Calibration of Bursting Strength Tester