Understanding dilution and seeding procedures in …

1 World Bank & Government of The Netherlands fundedTraining module # WQ - 16 Understanding dilution andseeding procedures in BOD testNew Delhi, May 1999 CSMRS Building, 4th Floor, Olof Palme Marg, Hauz Khas,New Delhi 11 00 16 IndiaTel: 68 61 681 / 84 Fax: (+ 91 11) 68 61 685E-Mail: Consultants BV & DELFT HYDRAULICS withHALCROW, TAHAL, CES, ORG & JPSH ydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 1 Table of contentsPage1 Module context22 Module profile33 Session plan44 Overhead/flipchart master55 Evaluation sheets216 Handout237 Additional handout298 Main text31 Hydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 21.

2 Module contextThis module deals with Understanding the need and procedures for dilution and seedingrequired for biochemical oxygen demand measurement. Modules in which prior training isrequired to complete this module successfully and other available, related modules in thiscategory are listed in the table designing a training course, the relationship between this module and the others, wouldbe maintained by keeping them close together in the syllabus and place them in a logicalsequence. The actual selection of the topics and the depth of training would, of course,depend on the training needs of the participants.

3 Their knowledge level and skillsperformance upon the start of the titleCodeObjectives1 Basic water quality conceptsWQ - 01 Become familiar with the commonwater quality parameters Appreciate important water qualityissues2 Basic chemistry conceptsaWQ - 02 Convert units from one to another Understand the concepts ofquantitative chemistry Report analytical results with correctnumber of significant digits3 How to prepare standardsolutionsaWQ 04 Recognise different types ofglassware Use an analytical balance andmaintain it Prepare standard solutions4 Understanding the chemistryof dissolved oxygenmeasurementaWQ - 11 Appreciate significance of DOmeasurement Understand the chemistry of DOmeasurement by Winkler method5 How to measure dissolvedoxygen (DO)

4 AWQ - 12 Measure dissolved oxygen in watersamples6 Understanding biochemicaloxygen demand testaWQ - 15 Understand the significance andtheory of BOD test7 Understanding chemicaloxygen demand testWQ - 18 Appreciate significance of CODmeasurement Understand the chemistry of CODmeasurementa prerequisiteHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 32. Module profileTitle: Understanding dilution and seeding procedures in BODtestTarget group:HIS function(s): Q1, Q2, Q3, Q5 Duration:1 session of 60 minObjectives:After the training the participants will be able to: Understanding the need and procedure for dilution andseeding in BOD measurementKey concepts: Significance dilution Seed and seed correctionTraining methods:Lecture, exercises and open discussionTraining toolsrequired:OHSH andouts:As provided in this moduleFurther readingand references: Standard Methods.

5 For the Examination of Water andWastewater, APHA, AWWA, WEF/1995. APHAP ublication Chemistry for Environmental Engineering, Sawyer, McCarty and Parkin. McGraw-Hill, 1994 Hydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 43. Session planNoActivitiesTimeTools1 Preparations2 Introduction Recapitulate BOD reaction Introduce the lecture topics5 minOHSD ilution Explain limited solubility of oxygen in water, itsinfluence on reaction rate and need for dilution Explain requirements for dilution water and dilutionprocedure5 min20 minOHSOHSS eeding Explain the meaning and need for seeding Ask participants for examples where seeding wouldbe required Describe how an appropriate seed may be obtained Describe the need and procedure for seed correction5 min10 min10 minOHSOHSOHSC onclusion Briefly review the material covered in the lecture andinvite comments5 minHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 54.

6 Overhead/flipchart masterOHS format guidelinesType of textStyleSettingHeadings:OHS-TitleArial 30-36, with bottom border line (not:underline)Text:OHS-lev1 OHS-lev2 Arial 24-26, maximum two levelsCase:Sentence case. Avoid full text :Use occasionally and in a consistent wayListings:OHS-lev1 OHS-lev1-NumberedBig for definite series of roman numbers and :None, as these get lost in photocopyingand some colours do not reproduce of a table will ease horizontalalignment over more lines (columns)Use equation editor for advancedformatting onlyHydrology Project Training Module File.

7 16 dilution and Version 05/11/02 Page 6 Recapitulate Biochemical oxygen demand Measures oxygen equivalence of aggregate organic mattermicro-organismsOrganic matter + O2 H2O + CO2 Both oxygen and micro-organisms are necessary for the testHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 7 Necessity and procedure for dilution SeedingHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 8 Dissolved Oxygen Min. conc. during incubation period 1 mg/L Lower conc. limits BOD reaction rate Limited solubility in fresh Project Training Module File: 16 dilution and Version 05/11/02 Page 9 dilution of samples BOD should be < 7 mg/L Min.

8 DO consumption 2 mg/L for reliability Grossly polluted waters & wastes need dilution Unpolluted surface waters have BOD < 7 mg/LHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 10 dilution water Should not contain organic matter Prepared from distilled water Contains buffer and inorganic nutrients Saturated with DOHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 11 dilution procedure % mixture = (vol. of sample/ vol. of diluted sample)x100 Two procedure separate container pipetting into BOD bottleHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 12 Using separate containerRange of BOD% mixture1,000 - 3, 400 - 1, - - - 20 - 10 - - - Project Training Module File: 16 dilution and Version 05/11/02 Page 13 Direct pipetting into 300mL bottlesRange of BODmL sample1,200 - 4, 600 - 2, 300 - 1, 120 - 60 - 30 - 12 - 6 - 0 Project Training Module File.

9 16 dilution and Version 05/11/02 Page 14 Choice of dilution BOD = (DO consumed/ % mixture) x 100 When in doubt, use more than one dilution Example: when three dilutions were usedS NoDilution% mixtureInitial DOmg/LFinal DOmg/LO2 result at 3, why?Hydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 15 Preparing dilution Incubate bottles in duplicate Example: Estimated BOD, 30 mg/L, use 10% dilution (why not20%?) prepare 1000 mL dilute sample 0 day 1 bottle = 300 mL 3 day 2 bottles = 600 mL there will be some spillage, make 1L diluted sample mix 100 mL sample with 900 dilution waterHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 16 seeding Provides micro-organisms to oxidise organic matter Not required for municipal wastes, biologically treated effluents, surface watersamples Some industrial wastes may require seeding exotic or difficult to degrade, high temperature, extreme pH, toxicsubstancesHydrology Project Training Module File.

10 16 dilution and Version 05/11/02 Page 17 Source of seed Settled sewage Soil culture Receiving waterHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 18 Seed correction Organic matter transferred with the seed Seed control Corrected BOD value of the sampleP)B(Bf)D( ,BODT0T013,27 = D = DO in diluted & seeded sample, 0 & T daysB = DO in seed control, 0 & T daysf = (% seed in diluted sample)/(% seed in seed control)P = % mixture/100 Hydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 19 Example Seed control estimated BOD 150 mg/L, dilution 2% BO & BT = & mg/L, respectively Sample estimated BOD 800 mg/L, dilution seed 4 mL/1000 mL or DO & DT = & mg/L, respectivelyHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 20 Example = = = = ( ) ( )BOD = mg/LHydrology Project Training Module File: 16 dilution and Version 05/11/02 Page 215.