Republic Services has been an Oasis client since 2004. Oasis has performed Construction Quality Assurance (CQA) services on many Republic landfill construction projects at Timberlands Sanitary Landfills as well as at other sites since that time.  Oasis performed CQA services at Timberlands for Cells 5 and 7. For Cell 9, Oasis provided design and contract document production, bidding assistance, construction administration, CQA, and certification services. Each cell consisted of a Subtitle D composite-lined disposal cell for municipal solid waste (MSW) with an alternate liner system.

During the design of Cell 9, Oasis was instrumental in modifying the master leachate collection and disposal system to avoid the originally-conceived plan of installing a new dual-containment force main parallel to an existing force main; this was important to prevent potential damage to the existing force main which was difficult to locate; also, the new design provided a solution that would result in positive ramifications for the future.  Oasis’ alternative approach, which was approved by the Alabama Department of Environmental Management, provided for the rerouting of Cell 9 and the future Cell 10 leachate to a new gravity line and new pump station that would convey leachate to the leachate tank. The new pump station was designed so that in the future all leachate could be redirected from the leachate tank to a newly installed and operational wetlands treatment system.

Oasis also redesigned the leachate sump riser pad configurations to incorporate dual-contained piping, concrete headwalls, and concrete pads with pipe bollards to replace previous plywood enclosure designs that had single-wall piping and electrical components in close proximity.  This new design not only reinforced but also protected the leachate system piping and electrical control components.