dswma 2016 final cover construction - …...final cover was completed in three phases. phase i of...
TRANSCRIPT
DSWMA SOUTH LANDFILL FINAL COVER CONSTRUCTION
Engineering and Environmental Solutions, LLC Blaine Litteral
CLOSURE OVERVIEW
§Final cover was completed in three phases. §Phase I of closure was completed in 1997 & 1998
closed 6.59 acres. §Phase II was completed in 2013 closing 11.05 acres. §Phase III was completed in 2016 closing the final 5.27
acres of the south landfill. §Active gas collection was installed in 3 phases in 1997,
2012 and 2016.
E & E Solutions, LLC
South Landfill Map
E & E Solutions, LLC
CLOSURE OVERVIEW
§Phase I included PVC cover FML over areas lined with single PVC liner. §Phase II and III included a composite cover system of
LLDPE FML and GCL materials over areas lined with a double composite liner system that included GCL, HDPE FML, and drainage composite components.
E & E Solutions, LLC
SETTLEMENT ISSUES IN DESIGN §Observed significant
settlement of final cover between construction of each phase. §Required redesign of cover
grades resulting in loss of airspace. §Expect field adjustments at
the tie in to older cover areas.
E & E Solutions, LLC
Adjustment between 2013 and 2016 final cover.
E & E Solutions, LLC
LIMITTING AIRSPACE LOSS DUE TO SETTLEMENT §Use of temporary covers to
increase time before closure to allow refilling settled areas. §Avoid terminated closure
phase perpendicular to the slope and avoid closure boundary that runs across slope when possible.
E & E Solutions, LLC
The flow from the secondary collection system began exceeding regulatory limits following construction of the second phase of final cover.
SECONDARY FLOW EXCEEDANCES
E & E Solutions, LLC
INVESTIGATION OF SOURCES §Analytical testing showed
liquid was representative of storm water. § Investigation into the
source identified two suspected points of entry for the storm water.
E & E Solutions, LLC
Leakage around leachate pump station and poor drainage combined with flaws in primary to secondary welds at site perimeter.
TWO CAUSES IDENTIFIED BY THE INVESTIGATION
E & E Solutions, LLC
LEAKAGE AT PUMP HOUSE § It was discovered that
storm water was building up on top of the final cover/exposed primary liner. §Attachment of liner system
to pump house provided liquid entry to secondary.
E & E Solutions, LLC
Primary liner connection at building corner.
E & E Solutions, LLC
Leakage around leachate pump station was addressed by sealing apparent openings, installing a rain flap to direct storm water away from the building liner connection and providing additional drainage.
PUMP HOUSE LEAK CORRECTIVE ACTION
E & E Solutions, LLC
PERIMETER ANCHOR TRENCH §Storm water was also found to
be building up within the perimeter anchor trench . § Flaws in the primary liner
within the trench were believed to be a source of water to the secondary collection system. §Road at perimeter of site
prevents drainage away from lined area.
E & E Solutions, LLC
Recommended Cover - Primary -Secondary Liner connection at perimeter.
E & E Solutions, LLC
A rain flap and toe drain was installed over the perimeter welds to prevent storm water from collecting over the perimeter anchor trench.
PREVENT STORM WATER ACCUMILATION IN THE COVER
E & E Solutions, LLC
OTHER CONSIDERATIONS
§Pump houses should be set sufficiently away from liner system so liner does not need to be connected to the building. Standard side slope riser pumping system may be preferred. §Provide space between landfill liner system and
perimeter road to allow storm water to be drained away from landfill.
E & E Solutions, LLC
ANY QUESTIONS?
Blaine Litteral - 616.566.4609 [email protected] Engineering & Environmental Solutions, LLC www.goEESolutions.com