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Procedure for Analysis of Treated Effluent

  • Objective:To lay down a Laboratory procedure for the analysis of Treated Effluent.
  • Scope:This standard operating procedure is applicable for formulation plant of pharmaceutical company.
  • Responsibility: ETP chemist shall be responsible for testing of Treated Effluent.
  • COD :  Chemical Oxygen Demand
  • D.O :Dissolved Oxygen
  • FAS : Ferrous Ammonium Sulfate
  • BOD : Biochemical Oxygen Demand
  • Abbreviations & Definitions:
  • Accountability:Head-Engineering and QA shall be accontable for compliance of the SOP.
  • Procedure
    • Biochemical Oxygen Demand
      • Apparatus:
        • BOD bottles
        • BOD Incubator
  • Prepare reagents as per SOP titledPreparation and Handling of Solutions in ETP Laboratory”, Annexure-I.
  • Mix the solution by inverting bottle few times and allow settling the precipitate.
  • Add 2 ml MnSO4 solution and 2 ml of alkali azide solution to the sample collected in 300 ml BOD bottles.
  • Determination of Dissolved Oxygen:
  • Determine the D.O content of another bottle immediately.
  • Keep one bottle for 3 days in the incubator at 27°C and determined its D.O. after three days.
  • Fill two BOD Bottle (300 ml each).with the above solution.
  • Take suitable portion of sample in a volumetric flask and dilute to one litre with dilution water. Mix thoroughly.
  • Adjust pH of the dilution water to 7.0 by using NaOH or HCl.
  • Add 1 ml each of phosphate buffer, Magnesium sulphate, Calcium Chloride and Ferric Chloride solution for each litre of dilution water and mix thoroughly.
  • Prepare dilution water in a glass container by bubbling compressed air in distilled water for about 2 hrs.
  • Similarly for blank, take 2 bottles for dilution water .determine D.O.content of one bottle immediately and determine the D.O. of another bottle after 3 days incubation (27°C)
  • Titrate 200 ml of the above solution with 0.025 N sodium thiosulphate using starch indicator.
  • Then add 2 ml of conc. H2SO4 to dissolve precipitate.Restopper the bottle and mix by inverting bottle few times.
  • Calculations:
  •  BOD mg/litre=           (D1-D5) – (B1-B5)  / % of Sample
  • Where,
  • D1= ml of 0.025N sodium thiosulphate consumed by sample
  • D2= 0.025 N sodium thiosulphate consumed after incubation of sample
  • B1= ml of 0.025 N sodium thiosulphate consumed by blank
  • B2= ml of 0.025 N sodium thiosulphate consumed by incubation of sample.


  • Chemical Oxygen Demand
  • Apparatus
  • Reflux Condenser
  • ml flat bottomed flasks with standard joint
  • Heating mantle (hot plate)
  • Prepare reagents as per SOP titled “Preparation and Handling of Solutions in ETP Laboratory”, Annexure-1.
  • Take 10 ml standard K2Cr2O7 solution in flask. To that add 20 ml of sample or suitable portion. Make up to 200 ml with distilled water.
  • Add 1g or a pinch of mercuric sulphate powder and several glass beads.
  • Add 30 ml of sulfuric acid reagent with mixing to dissolve HgSO4.
  • Attach flask to the reflux condenser and turn on cooling water .Reflux for 1.5 to 2 hrs.

CAUTION:    Mix reflux mixture thoroughly before applying heat to prevent local heating of the flask bottom and a possible blowout of flask contents.

  • Disconnect condenser and dilute mixture with 80 ml distilled water.
  • Cool to room temperature and titrate excess K2Cr2O7 with FAS, using 0.10to 0.15 ml ferroin indicator. End point is wine red colour.
  • Calculations:
  • COD as mg O2/L =     (A-B) X M X 8000   X dilution factor* / ml of sample
  • Where, A = ml FAS used for blank
  • B = ml FAS used for sample
  • M = Molarity of FAS
  • * = If sample is diluted


  • Total Suspended Solids
  • Apparatus
  • Vacuum pump
  • Filtration assembly
  • Filtered discs
  • Silica or Gooch crucible
  • Glass Desiccator
  • Insert disc with wrinkled side up in filtration apparatus and apply vacuum .Wash disc with reagent grade water.
  • Take suitable amount of sample and filter it. Wash the filter paper with 10 ml reagent grade water and continue applying vacuum for about three min. after filtration is complete.
  • Remove filter paper from filtration apparatus and carefully transfer to an aluminium disc as a support. Remove the crucible and filtration combination from crucible adapter if Gooch crucible is used.
  • Dry at 103 to 105°C in an oven, cool in a desiccator to balance temperature and weigh. Repeat the cycle until a constant weight is obtained or weight change is less than 4%.
  • Calculations:
  • mg total suspended solids/L =   A-B x 1000 / ml of sample
  • Where, A = Weight of filter + dried residue, mg, and
  • B  = Weight of filter, mg.


  • Then add 10 ml CCl4, shake well and allow standing for 5 minutes. Repeat the procedure for 3-4 times i.e. add total 30-40 ml of CCl4.
  • Take 50 ml of sample in a separating funnel and add 2-3 ml conc. HCl.
  • Weigh 100 ml silica or glass dish.
  • Prepare reagents as per SOP titled “Preparation and Handling of Solutions in ETP       Laboratory”, Annexure- I.
  •  Water bath
  • Silica or Glass dish
  • Filter paper
  • Separatory funnel
  • Apparatus
  • Oil & Grease
  • B  = Weight of Dish, mg.
  • Where, A = Weight of Dried residue + Dish, mg, and
  • mg total dissolved solids/L = A-B x 1000 / ml of sample
  • Calculations:
  • Transfer total filtrate(with washings) to a weighing evaporating dish and evaporate to dryness in a drying oven at 180° + 2°C,cool on desiccator and weigh. Repeat the cycle until a constant weight is obtained or weight change is less than 4%.
  • Total Dissolved Solids
  • Apparatus
  • Filter discs
  • Filtration Apparatus
  • Membrane filtration funnel
  • Gooch crucible
  • Drying Oven
  • Insert disc with wrinkled side up in filtration apparatus and apply vacuum .Wash disc with reagent grade water.
  • Heat clean dish in an oven at 180°C, cool in a desiccator and weigh immediately before use.
  • Take suitable volume of sample and filter. Wash with 30 ml reagent grade water allowing complete drainage.
  • Take the lower layer through separating funnel in dish and discard the remaining part.
  • Evaporate CCl4 or Petroleum ether on water bath and take the final weight of dish after cooling in a desiccator.
  • Calculations:
  • Oil & Grease, mg/L =    (A-B) X 1000000  / V
  • Where,
  • A= final weight of dish in gram.
  • B= Initial weight in gram.
  • C= Volume of sample in ml.
  • pH
  • Apparatus:
  • pH meter
  • Beakers
  • Prepare standard solution of 4.0,7.0 and 9.2 pH by using pH buffer tablets in 100 ml distilled water for each tablets.
  • Operate pH meter as per SOP and standardize with standard pH buffer solutions.
  • Determine the pH of the effluent at Different stages viz.Equilisation Tank (S1), Flash mixer (S2), Primary Clarifier (S3) and Treated water (S4).

NOTE: Standardize the pH meter with standard buffer solutions every day before Operation.

  • Forms and Records
  • Logbook For ETP Plant-Treated Effluent – Annexure-I
  • Distribution
  • Master Copy: Documentation Cell
  • Controlled Copies : Engineering, Quality Assurance, ETP Laboratory
  • History
Date Revision


Reason for Revision
00 New SOP



About Pharmaceutical Guidanace

Mr. Shiv Kumar is the Author and founder of pharmaceutical guidance, he is a pharmaceutical Professional from India having more than 14 years of rich experience in pharmaceutical field. During his career, he work in quality assurance department with multinational company’s i.e Zydus Cadila Ltd, Unichem Laboratories Ltd, Indoco remedies Ltd, Panacea Biotec Ltd, Nectar life Science Ltd. During his experience, he face may regulatory Audit i.e. USFDA, MHRA, ANVISA, MCC, TGA, EU –GMP, WHO –Geneva, ISO 9001-2008 and many ROW Regularities Audit i.e.Uganda,Kenya, Tanzania, Zimbabwe. He is currently leading a regulatory pharmaceutical company as a head Quality. You can join him by Email, Facebook, Google+, Twitter and YouTube

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