SOP for Operation and Maintenance of Demineralization Plant (DM Plant)

OBJECTIVE

The objective of this procedure is to provide operation and maintenance instructions for the Demineralization Plant (DM Plant) as per safety and cGMP requirements.

SCOPE

• This SOP covers the instructions for the operation & maintenance of the DM Plant.
• The SOP also covers preventive maintenance schedules and gives guidelines for maintaining critical spares generally required for maintenance.
• The SOP specifies the responsibilities of staff for the various functions outlined here under.

SYSTEM REQUIREMENT

Several minerals readily dissolve into raw water. DM Plant removes mineral salt by an ion exchange process from the raw water. After demineralization water passes through the fine filtration and UV sterilizer so that the water meets all the specifications of pharmaceuticals for purified water.

SYSTEM DESCRIPTION

• The DM Plant consists of water feed pumps (one working one stand-by) with motor, activated carbon filter, strong acidic Cation unit, strong alkaline anion unit, Mixed bed unit, 5-micron filter, UV sterilizer, interconnected pipe work with valves & ejectors, pressure gauges, flow meter, conductivity meter, etc.,
• In an Activated carbon filter (ACF), Activated carbon used is in granular form which is filled in a mild steel pressure vessel. ACF eliminates suspended solids and absorbs most pollutants dissolve in water like detergents, phenols, and obnoxious gases like chlorine & sulfur dioxide. It also helps to reduce the impurities like color, taste, etc.

AAA

• The Cation Exchange column of MSRL material contains strongly acidic Cation Exchanger resin. The Cation Exchange material, exchanges Cations such as Calcium, Magnesium, and Sodium for hydrogen ions to form the corresponding acids. This process is reversed when the resin is regenerated by hydrochloric acid through the column.
• The Anion Exchange column of MSRL material contains a strongly basic Anion resin. The strongly basic Anion Exchanger will remove the acid formed by the cation exchange material and produce water, which is free from dissolved solids. This process is reversed when the resin is regenerated by Caustic Soda solution Mix bed Exchange column of MSRL material contains Cation and Anion resins and is thoroughly mixed with compressed air. When the water passes through the Mixed Bed Column the traces of dissolved salt leaked out will be retained in the Mixed Bed Column.
• A conductivity meter is used to show the purity of dematerialized water. The conductivity is proportional to the residual ionized solids in the water. Low conductivity indicates water of high purity.
• 5-micron filters with SS housing remove particular impurities from the water.
• UV as a disinfectant is used for removing microbial reduction.
• The unit is fitted with all necessary piping, valves & ejectors from the raw water inlet and to the DM water outlet.

OPERATING PROCEDURE

• Ensure before starting up - First time after every maintenance:
• Ensure that the Activated carbon filter, Cation, Anion, Mix bed, and vessel are filled with the specified and required quantity of resin.
• Ensure that all valves are in operation.

AAA

• Check that all piping work is carried out as per the piping drawing given in the manufacturer’s manual.
• Ensure that there is no water leakage.
• Ensure that the DM plant feed water pump gives the rated flow and pressure required for the DM plant.
• Test the water inlet quality. It should be as per the specifications given in the design data.
• Ensure raw water pressure at the inlet is not less than 1.7 to 2 kg/c㎡.

ALSO READ: SOP for Preventive Maintenance for DM Plant

Starting Procedure / Instruction of DM Plant

• Open the raw water inlet valve leading to the suction line of the DM plant feed water pump.
• Switch ON the DM plant feed water pump.
• Slowly open the pump discharge valve leading to the inlet valve of the DM plant.
• Open the Cation inlet valve V1.
• Open the Anion inlet valve V5 and rinse outlet valve V7
• Adjust V7 to get the specified rinse flow to drain.
• Open valve V12 to allow some flow through the conductivity cell.
• Switch ON the conductivity meter to ‘CALIBRATE’
• If the needle on the meter indicates exactly 40, move to the ‘READ’ position.

AAA

Stopping Procedure / Instruction of DM Plant

• Switch OFF the conductivity meter.
• Switch OFF the DM water feed pump.
• Close the Anion outlet valve V6.
• Close the Anion inlet valve V5.
• Close the Cation inlet valve V1.
• Close the GIDC inlet raw water valve.

Acid Injection

• Prepare the stipulated quantity of acid + demineralized water solution by stirring in the measuring tank.
• Open the main raw water inlet valve V1, and acid ejector power water valve V3.
• Open the acid outlet valve V10.
• Open the acid ejector suction valve V4.
• Adjust V3 to maintain the specified flow to drain, such that the acid measuring tank is emptied in the specified time, leaving only a dead level of 25 mm in the tank.
• Now close valve V4.

Acid Rinse

• Adjust valve V3 to maintain specified flow for the specified time.
• At the end of this specified period, it is advisable to take a sample from valve V10 and test it for pH with the help of a pH strip.
• If the result of the test is satisfactory, close valves V10 and V3.

AAA

Soda Injection

• Prepare the stipulated quantity of caustic soda + dematerialized water solution by stirring in the measuring tank.
• Open the main raw water inlet valve V1, and caustic ejector power water valve V8.
• Open the caustic outlet valve V11.
• Open the caustic ejector suction valve V4.
• Adjust V8 to maintain the specified flow to drain, such that the acid measuring tank is emptied in the specified time, leaving only a dead level of 25 mm in the tank.
• Now close valve V9.

Soda Rinse

• Adjust valve V3 to maintain specified flow for the specified time of 30 min..
• At the end of this specified period, close valves V8 and V11.
• Final Rinse:
• Open valve Anion inlet valve V5 and final rinse outlet valve V7.
• After 20 minutes, open conductivity cell isolation valve V12
• Switch ON the conductivity tester. Reading must be below 30 uS/cm.
• Close final rinse outlet valve V7.
• Open Anion outlet valve V6 to send DM water to service.
• After 30 to 40 minutes we can get an acceptable level of conductivity
• Ensure prior to start-up of Mixed Bed Unit – Only first time:
• Ensure that the mixed bed vessel is filled with the specified and required quantity of resin.
• Ensure that all valves are in operation.
• Check that all piping work is carried out as per the piping drawing given in the manufacturer’s manual.
• Ensure that there is no water leakage.
• Test the water inlet quality. It should be as per the specification given in the design data.

AAA

Preparation of Regenerants

• Prepare the 6L Hydrochloric Acid + 30L dematerialized water solution (10%) by stirring in the measuring tank.
• Prepare the 2.6 kgs Caustic + dematerialized water solution (10%) by stirring in the measuring tank.

ABBREVIATION

SOP: Standard Operating Procedure

DM: De-Mineralised

UV: Ultra Violet

ANNEXURE

Nil

REVISION HISTORY

Nil

ALSO READ: SOP for Measurement of Airflow Velocity and Air Changes per Hour