Anatomy of the Landfill
There is a lot that goes into a landfill - not just the waste, but also the management and preparation for waste collection. In fact, Springfield’s Noble Hill Sanitary Landfill dispels the notion of a landfill just being a dumpsite. Rather, our staff are dedicated to creating an environmentally safe space to dispose of accepted wastes.
1. Leachate Collection & Filtration System
This system collects the leachate (liquids that percolate through the solid waste and collects dissolved and suspended particles on its journey) that is trapped inside the landfill and moves it through the piping to the wastewater plant for treatment and disinfection.
2. Prepared Subgrade & Compacted Soil
The natural earthen material under a landfill site was prepared through the removal of unwanted material (topsoil, vegetation, large rocks) to prepare for the construction of the landfill site. Additionally, soil is compacted to help prevent soil and groundwater contamination.
3. Geo-Membrane Liner
A plastic liner that prevents soil and groundwater from combining or even contacting buried solid waste. This liner is a very durable HDPE (High Density Polyethylene) that is also puncture-resistant.
4. Gravel & Rock Filler
Serves as a pervious substrate that helps to provide filtration of leachate from the landfill to the collection and filtration system.
5. Geotextile Filter Fabric
A fine layer of fabric that helps to prevent fine material from clogging the leachate collection system.
6. Landfill Gas Collection Well
In the landfill, as materials break down, in active or closed cells, they release a combination of methane and other gases that we call landfill gas. Since this gas has the potential to burn or explode, it is removed from the landfill to be vented or burned using a series of pipes.
7. Closed Cell or Cover
When a section of the landfill is filled to capacity, it is closed and permanently covered with a combination of a layer of polyethylene plastic, compacted soil and a layer of topsoil that will be seeded to support growth of vegetation that will prevent erosion.
8. Groundwater Monitoring Well
These wells are used for direct access to groundwater that is regularly collected and tested to ensure no leachate is present.
The Life of a Landfill
Due to the compacting of solid wastes, decomposition times are drastically decreased. Because of this, landfills do not go away and after they are full they still demand careful monitoring to ensure they are not impacting groundwater or soil. Many landfills are many acres large and as they fill up over time, the space for new waste is reduced and sometimes eliminated. This is why it is important to consider sustainable means, recycling and composting as a way to stretch the viability of our landfill space.