May 2, 2011
I would like to take this opportunity to give you our fifty-fourth monthly update on the project.
I am currently reviewing the year four quarter three report and it contains the data and updated milestones (see below for milestone summary). The run time has been good and there hasn’t been any down time notices lately. An expanded evaluation of the milestone data from last update is included here.
System Runtime & Performance:
The run time has been pretty good. All of the air sparging wells is showing good flow to the subsurface as designed. Three of the multiphase treatment well network of 26 (originally 24) are turned off. In other words there are only 23 vapor recovery wells being used to capture vapors. Only the ones in the area of the contamination are being used to recover groundwater. The target area is still the isolated area around monitoring wells MW-5, AW-10 & AW-28. The soil vapor extraction blowers (the spare) problem I reported on last month still hasn’t been fixed. We have two soil vapor extraction blowers, of which only one is operable. This hasn’t affected run time or efficiency though since of them is a spare and the intent is to rotate periodically between them. There still hasn’t been any shutdowns or problems caused by the infiltration gallery getting overwhelmed from heavy rain events.
I am currently reviewing the Year Four Quarter Three report (received 04/12/11). The next report is the Year Four Quarter Four (the annual report) and is due on July 12, 2011. A milestone evaluation from this report is summarized below.
For the first time, all wells have met milestones. The site has the lowest amount of contamination to date, with only minor concentrations in two wells.
· AW-10 – This well is completely below groundwater target levels for the first time.
Benzene -not detected March 17, 2011 (8.1 ug/L November 4, 2010)
Ethyl benzene - not detected March 17, 2011 (145 ug/L November 4, 2010)
Total Xylenes - not detected March 17, 2011 (147 ug/L November 4, 2010)
Naphthalene - not detected March 17, 2011 (23.4 ug/L November 4, 2010)
· AW-28 - This well is almost below groundwater target levels for the first time. The only detected contaminants above target level are Benzene and Total Xylenes, each of which are only one part per billion above the state prescribed groundwater cleanup level:
Benzene -1.2 ug/L March 17, 2011 (91.3 ug/L November 4, 2010)
Ethyl benzene – (11.0 ug/L) detected but below cleanup levels March 17, 2011,(565 ug/L November 4, 2010)
Total Xylenes – 21.1 ug/L March 17, 2011 (351.9 ug/L November 4, 2010)
Naphthalene – (1.2 ug/L) detected but below cleanup levels March 17, 2011, (48.4 ug/L November 4, 2010)
· MW-5 – This well is also completely below and shows most dramatic reduction of all the wells.
Benzene -not detected March 17, 2011 (89.8 ug/L November 4, 2010)
Ethyl benzene - not detected March 17, 2011 (525 ug/L November 4, 2010)
Total Xylenes - not detected March 17, 2011 (577 ug/L November 4, 2010)
Naphthalene - not detected March 17, 2011 (82.8 ug/L November 4, 2010)
Other wells that were sampled on March 17, 2011 include AW-26, AW-27, and DW-11. The only detected contaminant in any of these three wells is Benzene was found in DW-11 at a concentration of 15.9 ug/L. This well has fluctuated from below cleanup levels to 25.1 ug/L over the course of the cleanup. This well and several others will be sampled in the upcoming comprehensive annual sampling event. This data will be available sometime around early July.
I suspect that once the results come back for the early summer sampling event (sometime in June) we may approve a recommendation to turn the system off for good.
I look forward to sending the next update on June 1, 2011. Please feel free to call me anytime if you need additional information or have any questions.
Environmental Case Manager
Environmental Protection Division
800 Mercy Drive, Suite 4
Orlando, FL 32808