Laserfiche WebLink
Investigating probes at Corral ow Landfill Page 1 of 1 <br /> Frank Girardi [EH] <br /> From: Michael Carroll [mcarroll@co.san-joaquin.ca.us] <br /> Sent: Monday, December 20, 2004 2:49 PM <br /> To: Tony Svorinich (Tony Svorinich) <br /> Cc: Annette Borges; Dan Johnson; Robert McClellon [EH]; Frank Girardi [EH] <br /> Subject: Investigating probes at Corral Hollow Landfill <br /> Good afternoon Tony, <br /> As you may know, our LEA has asked us to verify that the probes at migration monitoring wells G-1, -2, and-6 at <br /> the Corral Hollow Landfill are OK for monitoring subsurface migration of LFG. Their concern springs from the <br /> observation that, at these three wells, noticeable vacuum remains in the probe when the sample is taken. I know <br /> that a number of things could cause this, such the probe being installed in tight clayey soil or particulates <br /> obstructing the holes in the sampling pipe. High vacuum residual could also indicate that the sampling pipe is <br /> plugged, thus preventing the collection of a sample sufficient to measure the subsurface concentration of <br /> combustible gas. We have asked SCS to check out two of these probes in the past, but the procedure for <br /> checking them was not formalized at that time. <br /> To verify that we can collect a sample from the wells, we will use the same procedure that we used at the Harney <br /> Lane Landfill. We will operate SCS's GEM combustible gas meter, and measure the vacuum that the GEM <br /> applies to each probe when making a measurement. Then we will physically plug the sampling tube of the GEM, <br /> and measure the maximum vacuum that the instrument can apply. If the GEM can provide vacuum higher than <br /> needed to withdraw gas from the probe, then this should show that the probes are suitable to monitor subsurface <br /> migration. <br /> We would like to put this issue to rest as soon, so I ask that SCS check these probes at the monthly LFG well field <br /> adjustment in January. Robert McClellon asks that he and/or members of his staff be there at the time of this <br /> investigation, so please let me know at least TWO DAYS prior to your site visit, so we can coordinate our <br /> schedules. <br /> Thanks, and please call with any questions. <br /> Regards, <br /> Mike <br /> W. Michael Carroll, PE <br /> Senior Engineer, Solid Waste Division <br /> San Joaquin County Department of Public Works <br /> 209-468-8504 <br /> 12/21/2004 <br />