ASTM_D_932_-_15.pdf

Designation:D93215Standard 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 examination under the microscope.Thepractice provides for the identification of the following generaof bacteria found in water and water-formed deposits: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 the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.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 Closed ConduitsD5465 Practice for Determining Microbial Colony Countsfrom Waters Analyzed by Plating Methods3.Terminology3.1 DefinitionsFor definitions of terms used in thispractice,refer to Terminology D1129.4.Summary of Test Method4.1 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).6.5 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.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 Feb.1,2015.Published March 2015.Originallyapproved in 1947.Last previous edition approved in 2009 as D932 85(2009).DOI:10.1520/D0932-15.2For 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 States1 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 narrow,for handling thick samples.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Specification D1193,Type II.7.3 H