ASTM_D_932_-_20.pdf

Designation:D93220Standard Practice forFilamentous Iron Bacteria in Water and Water-FormedDeposits1This standard is issued under the fixed designation D932;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the determination of filamentousiron bacteria(FIB)by microscopic examination.This practiceprovides for the identification of the following genera ofbacteriafoundinwaterandwater-formeddeposits:Siderocapsa,Gallionella(Dioymohelix),Sphaerotilus,Crenothrix,Leptothrix,and Clonothrix.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D887 Practices for Sampling Water-Formed DepositsD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD3370 Practices for Sampling Water from Flowing ProcessStreamsD5465 Practices for Determining Microbial Colony Countsfrom Waters Analyzed by Plating Methods3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129.4.Summary of Practice4.1 The iron bacteria are generally filamentous,typicallyfound in fresh water,and frequently surrounded by a sheathwhich is usually encrusted with iron or manganese,or both(1,2).3However,Starkey(3)reports another type which isclassified among the true bacteria.Detection and identificationis accomplished by microscopic examination of sediment fromthe sample.4.2 This practice provides a qualitative indication of thedensity of the filamentous iron bacteria and the severity of theclogging problem in pipes caused by these bacteria.5.Significance and Use5.1 Filamentous iron bacteria is a general classification formicroorganisms that utilize ferrous iron as a source of energyand are characterized by the deposition of ferric hydroxide intheir mucilaginous sheaths.The process is continuous withthese growths,and over a period of time large accumulations ofslimy brown deposits can occur.Iron bacteria may clog waterlines,reduce heat transfer,and cause staining;objectionableodors may arise following death of the bacteria.The organicmatter in the water is consequently increased,and this in turnfavors the multiplication of other bacteria.6.Apparatus6.1 Centrifuge,complete with 250 mL conical bottles.6.2 Cover Glasses,round or square type,19 mm(34in.)indiameter.6.3 Filter Paper or Blotter.6.3.1 For 8.3.2.1 Grade 5(nominal 2.5 m particle-sizeretention).6.3.2 For 9.3 any absorbent paper medium will suffice.6.4 Containers,sterile 1 L glass or plastic(can be autocla-vable).1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.24 on Water Microbiology.Current edition approved May 1,2020.Published May 2020.Originallyapproved in 1947.Last previous edition approved in 2015 as D932 15.DOI:10.1520/D0932-20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.16.5 Membrane Filter,0.45 nominal pore size,with appro-priate filter-holding and vacuum assembly(see 9.2).6.6 Microscope that provides a magnification of 400 to1000 and is complete with a suitable light source.Adark-fieldcondenser is desirable.6.7 Pipets,Mohr-type,10-mL,with an opening 3 to 4 mmin diameter,for thick samples,and 1-mL Mohr-type pipets forthin samples or equivalent disposable plastic pipettes.6.8 Slides,glass,standard type,25 by 76 mm(1 by 3 in.)with either plain or frosted end.6.9 Spatula,small and narr