SOP for Preparation of Sodium Metabisulfite Solution ( SMBS )

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OBJECTIVE

To lay down the procedure for to provide a written procedure for preparation of Sodium Meta Bi Sulphite Solution

SCOPE

This SOP shall be applicable for the purified water system.


RESPONSIBILITY

Operator/ Engineer/ Executive


PROCEDURE 

  1. Calculation for SMBS dosing Flowrate:-

              Flow (m3/hr) x ppm of dosage

      =  ————————————————————–

          10 x Concentration of dosing solution

          2.5 x 6                         15

      =  ————— =           ———      =   1.5 LPH

          10 x 1                           10

Considering 24 hrs of operation 36 lts of solution need to prepared

  1. Preparation of SMBS solution of 1 % concentration
    1. Take 25.6 liters of fresh potable water in dosing tank.
    2. Add 400 gram of lab grade SMBS (98% weight/volume (w/v) concentration-approx.) in dosing tank and stir with the help of S.S. appro.
    3. Adjust dosing rate such that ORP is maintained at 250 mV approx.. & NaOCL is nill (This is checked by Free Chlorine Test Kit).
    4. Prepare and add fresh solution in the dosing tank in every day.
    5. Avoid low level situation in dosing tank.

NOTE:

  • Dosing solution should be prepared in soft water/ potable water only.
  • Dosing Solution should be replaced once in two days.
  • Dosing tank should cleaned every day

FAQ

Q.1. How much sodium metabisulfite to remove chlorine?

Ans. In theory, 1.34 mg of sodium metabisulfite will remove 1.0 mg of free chlorine. In practice, however, 3.0 mg of sodium metabisulfite is normally used to remove 1.0 mg of chlorine.

Q.2.What is SMBS dosing system?

Ans. An SMBS (Sodium Metabisulfite) dosing system is a setup used in water treatment processes to inject a precise amount of sodium metabisulfite into the water. This system is primarily used for dechlorination, where SMBS reacts with free chlorine in the water to neutralize it.

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