Welcome to the STI Engineering website. Our goal is to provide you with useful
information about our company and our scientific methods to assist you with landfill
STI Engineering has been performing in-situ landfill investigations since 1984. We
have developed a method to locate and profile gas pressure, liquid pressure and
vacuum zones in landfills and in the vadose zone. The process involves the use of
the side-sensing piezo-penetrometer cone (PPT) which is pushed into a landfill.
The data is continuously recorded the full depth of the landfill and inputted into a
computer. A 3-D profile of the conditions inside the landfill is created from this data.
For compliance issues this profiling is used to perform the following:
-Measure the thickness of the cover soil
-Determine the effectiveness of the cover soil by measuring the gas pressure
under the cover soil
-Design and construct landfill gas collectors
-Map out the daily cover layers and the thickness of refuse layers
-Detect pathways for subsurface gas migration and surface emissions
-Avoid installing collectors through pockets of liquid
-Map out the vacuum influence of existing collectors
-Determine the density of the native soil at the bottom of an unlined landfill
All engineering projects are only as good as the information they are designed from.
The 3-D Profile above was performed at a landfill in Southern California. This profile
was able to identify the cause of the impacted perimeter monitoring probe by LFG.
Note the lack of vacuum (pink) in the foreground of the profile. The LFG is migrating
straight to the probe which is to the right of the profile. Thick layers of liquid were
detected, which blocked vacuum from LFG layers (blue)
Push-in 2" diameter steel collectors should be installed in the LFG (yellow) area to
collect this LFG. This process eliminates a lot of the guess work in placing collectors.
Based on the knowledge obtained from decades of PPT investigations, STI has been
able to develop more advanced and patented technology used in the waste industry.
- Steam Injection in landfills - Enhances LFG production 10+ times
- Steam Injection Biomass Reactor - Converts 100% of the organic waste and
100% of the water into biogas
- CO2 Sequestration - Inject exhaust into landfill/biomass reactor and convert
it into more methane
- Algae Injection - Inject exhaust into alga tanks, harvest algae and inject it into
the steam stream and into the landfill/biomass reactor. Negative carbon
- Steam Landfill Fire Suppression - Extinguish subterranean fires with steam
Approach To Landfill
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landfill, landfill gas, gas collectors, gas-to-energy, Co-generation, biogas, anaerobic digester, biomass
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