A Method for Remediation By: Sara Hoovestol, P.G. What Are We - - PowerPoint PPT Presentation
Landfill Gas Migration: A Method for Remediation By: Sara Hoovestol, P.G. What Are We Going To Cover: Site Background Historical Landfill Gas (LFG) Measurements Investigation and Design of Remediation Method Construction of
By: Sara Hoovestol, P.G.
▪ Site Background ▪ Historical Landfill Gas (LFG) Measurements ▪ Investigation and Design of Remediation Method ▪ Construction of Trench ▪ How Did It All Turn Out ▪ Lessons Learned
▪ Bullets ▪ Bullets ▪ Bullets
Methane Monitoring Results June 2011-October 2013 GW-1R
Date Percent Methane by Volume in Air Percent of Lower Explosive Limit (LEL for Methane) 6/20/2011 32.7 654 9/28/2011 26.5 530 12/13/2011 14.5 290 3/5/2012 21.1 422 6/20/2012 21.4 428 10/25/2012 10.1 202 11/27/2012 1.7 34 3/14/2013 16.5 330 6/19/2013 28.7 574 9/10/2013 26.7 534
▪ Previously installed passive gas vents are not adequate ▪ Weaver Consultants Group developed a gas sounding method ▪ Gas sounding results were compared to the gas probe boring log ▪ Determined a general correlation between the sounding result interval and an angular gravel/sandstone cobble interval in the boring log
▪ The results of the investigation indicated LFG gas appeared to be migrating approximately 18 feet below ground surface. ▪ Weaver Consultants Group proposed the installation of a gas cutoff trench ▪ Design Objective: ▪ Induce vacuum at the depth of gas migration
(The Results)
Methane Monitoring Results October 2013-November 2018 GW-1R
Date Percent Methane by Volume in Air Percent of Lower Explosive Limit (LEL for Methane) 10/15/2013* 5.7 114 3/27/2014 6/16/2014 0.1 2 9/23/2014 11/4/2014 3/26/2015 6/26/2015 9/24/2015 11/3/2015 3/17/2016 6/9/2016 9/23/2016 11/15/2016 3/16/2017 6/22/2017 9/15/2017 11/1/2017 3/14/2018 6/20/2018 9/20/2018 11/7/2018
Methane Monitoring Results June 2011-September 2013 GW-1R
Date Percent Methane by Volume in Air Percent of Lower Explosive Limit (LEL for Methane) 6/20/2011 32.7 654 9/28/2011 26.5 530 12/13/2011 14.5 290 3/5/2012 21.1 422 6/20/2012 21.4 428 10/25/2012 10.1 202 11/27/2012 1.7 34 3/14/2013 16.5 330 6/19/2013 28.7 574 9/10/2013 26.7 534
Methane Monitoring Results 2016-2018 Trench Vents (near GW-1R)
Date Vent Number Percent Methane by Volume in Air Percent of Lower Explosive Limit (LEL for Methane) 3/17/2016 1 2 3 6/9/2016 1 0.9 18 2 3 9/23/2016 1 2 3 11/15/2016 1 2 3 3/16/2017 1 0.8 16 2 3 6/22/2017 1 4.7 94 2 3
Methane Monitoring Results 2016-2018 Trench Vents (near GW-1R)
Date Vent Number Percent Methane by Volume in Air Percent of Lower Explosive Limit (LEL for Methane) 9/15/2017 1 6.3 126 2 3 11/1/2017 1 0.4 8 2 3 0.2 4 3/14/2018 1 2 3 6/20/2018 1 10.9 218 2 3 9/20/2018 1 2 3 11/7/2018 1 2 3
▪ Importance of quality boring logs ▪ Do it once ▪ Proper construction quality assurance
Contact Information: Sara Hoovestol, P.G. shoovestol@wcgrp.com 720-529-0132