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CLEARWATTER <br /> : <br /> C ;R O U P,"r IN C. 3, <br /> ' The oxygen,utilization rates will be calculated as the percent'change ir► U2 over time. <br /> _- The "02 utilization rate_ is de_termined,as the slope of the 02% vs. time line_ (Downey <br /> :r <br /> et al":, 1992; ':Duporit 1993, ::Hirichee;"et ai,,:1992 . Mrller; 'e# .al. 1991). iii general, a <br /> i - zero-order respiration rate is seen during the°,first part of 'the test: `Occasionally,'the <br /> latt&r part of.-the "te't,�is��nfldenced by other factors, such as:natural diffusion from <br /> the surface;and-this part of the data curve xs.not used zz the calculations (Downey i <br /> et'al, 1992) ^ <br /> -...Bio ziAdzition Rates ' YY ; <br /> U'sing"the rnaxunum k rate of.oxygen uptake;'the rate at which.hydrocarbons will be a <br /> metabohzed can..,be calculated: .rpThe time::required�to completely <br /> down <br /> hydrocarbons.in. the"soil can "then be estimated assuming a,maximum;hydrocarbon- = <br /> concentration.m the.,soil. 'This-.estimate is-based on a•`non-rigorous calculation and <br /> is. perfdrmed�"only #o obtain, an. initial idea of projected length for cleanup; the <br /> projected length,for:cleanup_must``continually be re evaluated during.a:bioventing <br /> project, since`the.biodegradation rate-will`initially-increase as. microbial .popufations <br /> :adjust-'Jo, .the";additonaloxygen supplied.::and then, `decline as .hydrocarbon <br /> concentrations:decline: In general,-biodegradation rates.,for diesel and jet fuel range <br /> from 2 t6'-20 mg/kg=day'-(ppm/.day)., <br /> Calculated abiod'egradation `r`a'tes Hare based on. the utihzation ..r""ate and'",the F <br /> stoichiometry for•:hydrocarbori,mineralization:- -The following";,formula;:presented by <br /> Hinchee et al:. (19.93)"is used:for-'the.rate calculation: , t A . . _ <br /> Y .. . I <br /> K$ '-Ka A, Do k �1 <br /> ml , R F F <br /> i .. �. - ..T @-, .k � •F C . x111 <br /> Where <br /> —`816 e- rrate (mg/kg=day)`''. <br /> := <br /> "K 'oxygen utilization-rate (%02/day}:=-slope ofry. vs .Time i <br /> A- Volume of',air;in brie-kg-soil <br /> ; (L/kg);'ge.nerally`assuned:as-30%-airfin. <br /> lled . <br /> ompormzL' '. m30�C <br /> .O ):`= 1.33 kg/rf —1,33]o—Density- nLQ'mg/L:(at 1'atrn,2 <br /> C Ratio,qf Hydrocarbon to.oxygen".required for:min& liza ion: <br /> n ; For diesel contamination es't'imate the breakdown of n-decane. <br /> C1gH2z'+ 15.5Q2,= lO Cbz 1 l`HzO,;(C." 1Kg Hydxocarbori/3S kg 02) <br /> K' <br /> ' 'For . asoline contamination estimate the.breakdown of hexane:: <br />?} r C�H14 'f'9.5 02 — 6CO2.+ 7H2O, (C=;1Kg Hydrocarbon/3:5 kg 02)1 <br /> r� k r .. `I`Y'.,,•r '=, *' � i� Y' � {r' ��, _. L'K L1 �y ' r ,r _" - .. <br /> Situ Respiration Test Protocols ' g f :' ' Page 4 of 6 Aprn128, 1995 <br />