Laserfiche WebLink
ENSR AECOM <br /> ra s <br /> system, the next phase will be to upgrade the system components(e.g., using larger piping and compressors <br /> to deliver more air). This newer system would then be performance tested in the same fashion (less the <br /> collection of baseline data). De ending on the flow rate ecte a be necessary to operate the existing <br /> vent wells to control the migration o vapo -p ase VOCs that could be volatilize y a Ig er spargm rate. <br /> The upgraded system testing wou d initially be perform-e-without ozone addition to evaluate whether <br /> ' traditional sparging is sufficient to create the more oxygenated conditions that are expected to enhance <br /> biodegradation of hydrocarbons in the plume. After one year of operations, the system operational parameters <br /> (e.g., dissolved oxygen concentrations, subsurface pressure response, etc.) would be reviewed to determine <br /> whether further modifications to the system are necessary(e.g., addition of ozone or installation of additional <br /> sparge wells). <br /> 5.4 Recommendations for further assessment <br /> Given the greater than 1/4-mile distance to the nearest supply well and the steady-state nature of the plume,the <br /> fume ma not present a risk. Therefore, performing a huuaajhealth risk assessment, possibly incorporating <br /> ' fate and transport modeling, would be beneficial to determine whether rem edia actions at the site are <br /> necessary. <br /> Given the 10 years of data indicatin the f MTB TBE metabolites in the roundwater plume, <br /> analysis for these eters should be discontinued. <br /> 1 <br /> 1 <br /> r <br /> J:IRem_Eng\Project Files\P60(6000- <br /> 6999)16940-UNOCAL Portfolio Closure16940- 5-2 January 2006 <br /> ' UNOCAL Portfolio Closure\Sife 0187-Stackton <br /> East MinoACSM Report\CSM Repon_Final.doc <br /> s <br />