Landfill Operations in Detail…

Engineered Design: The initial step in creating a new landfill cell is the engineering. Twin hires Colorado engineers to design the cell which entails a minimum separation from groundwater, designing the liner system, engineering storm water runoff, determining locations for groundwater monitoring wells and gas wells, and designing leachate collection sumps.

Excavation: After the new cell is engineered, excavation commences. This entails removing all soils down to the engineered subgrade in preparation for the liner system.

Cell construction: Each landfill cell is lined with protective layers to prevent any escape from the landfill.  We start with 1.0 feet of clay  compacted in 6 inch layers to a hydraulic conductivity of 1 x 10 cm/sec or less.  On top of the compacted clay is a synthetic material called HDPE which is rolled out in sheets and welded together to create a waterproof seal. On top of the HDPE is a synthetic drainage layer to transport leachate to the sump. On top of the drainage layer is 16 ounce geotextile to protect the underlying liners.  On top of the geotextile is one foot of sandy soil composite which further protects the underlying liners but allows liquids to pass through.

Engineers again: Our engineers are on site throughout the entire process supervise the work and ensuring compliance with the engineered design.  The engineers compile daily reports which are submitted to the Colorado Department of Public Health and Environment for approval.  Once approved by the CDPHE and the County Health Department, Twin starts the process of disposing of your trash into the new cell.

Disposal: After the new cell has been permitted, Twin begins adding the “fluff layer” of trash to the cell. The fluff layer is soft household trash that is the first layer of trash into the new cell. The fluff layer further protects the liners from being punctured or damaged. Once the initial fluff layer covers the entire new cell we can go into operation and dispose of construction debris along with household trash.

Summary: The above process can take years to complete and Twin is continually working on new cell design, excavation, and construction to ensure your trash has an environmentally safe disposal site.  In addition, the groundwater and gas monitoring wells are sampled and analyzed twice each year to ensure there has been no escape from the landfill into the environment.