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r <br /> V REMOVAL <br /> J <br /> show decaving oscillating concentrations mlih time, reflecting the circular eater movement <br /> {Figure 6) <br /> 51F-Jvj-��- <br /> Doi <br /> 1 51F-Xx�_. <br /> + <br /> 01S <br /> 12346179910 0M123466789io <br /> TOM (ft") 'f O�AH i�ri1 <br /> asf order 124■ FMd ord■r 8 w Fast order D• <br /> Figure 6 Removal rate as a plot of log CCCO versus time to approximate first order decay rate <br /> for observed HVOC (6a) and BTEX(6b)removal. <br /> The process of removal of dissolved volatilesmes similar d to first order�reactions tion in she a the <br />• bodies. Elimination and detoxification pro correspond <br /> to the <br /> rate of decrease in concentration of the toxic substance is directly proportional <br /> concentration of the substance. 'The followring differential equation expresses the direct <br /> relationship between the rate of elimination and the concentration of the dissolved volatile <br /> compound. <br /> dcldt=-bC <br /> Nvbere. do=change in concentration of dissolved volatile <br /> dt=change in time <br /> b =fraction of volatile substance that leaves groundwater in one unit of time(day) <br /> 4- C=concentration of volatile compound <br /> If b=0 20,20 percent of the volatile substance present at any given time is eliminated <br /> per unit of time(day) To determine the actual amount of substance eliminated <br /> intervals unit <br /> of tie, <br /> the initial concentration vas compared to later concentrations m <br /> start of operation. The amount of material eliminated is obtained from: <br /> BC(dcldt)_fC <br /> where BC=volume of groundwater block(pnsm)containing the chlorinated substance <br /> C = concentration of volatile substance in ground,.%pater(ggA) <br />. f = a constant <br /> do = change in concentration of dissolved volatile <br /> 7 <br />