Soil Vapor Extraction Systems
Sub-Slab Depressurization Systems
Radon Mitigation Systems
These 5 names are for similar systems to
remove gases and chemical vapors from the soil to prevent harm. Soil Vapor Extration
Systems(SVES) are used to remove volatile chemicals from the soils, usually when the
chemicals are in the soils above the water table. Wells are installed and screened
above the water table and the screens are placed in the level of contamination. The
wells are piped together and the pipes go to a blower or fan to pull the vapors out of the
ground. If needed the exhaust from the fan can be treated with carbon to collect the
chemical vapors. For an example of this, please look at another page of this website: The
Perc Plume .
If the gases in the soil are under a house or
building, we can install a sub-slab depressurization system. This is similiar to the
SVES, but we do not need deep wells, we only want to pull the vapors out from under the
house so that the vapors do not go into the house. For this application we do not need
deep wells, we are not trying to remove the source- we are only trying to remove the
vapors under the house, to protect the house.
A hole is made in the basement floor, and a
shallow hole is dug in the soil under the floor. A pipe is installed in the hole, the rest
of the hole is filled with gravel and then cemented over. The pipe goes to a blower
and the exhaust from the blower goes to the outside air. When the fan is turned on, the
vapors under the house are pulled into the pipe, through the blower and then up and out above the house. This type of system is also
used to protect a house from naturally occuring radon gas.
Soil venting systems are also used on and
near landfills to protect buildings from methane gas. Methane is an explosive gas
that is produced from the decomposition of garbage or paper or wood. Sometimes
buildings are built on or near old landfills and soil venting is needed.
Closed landfills that are capped also need venting
to release the methane gas. Sometimes there is enough methane gas to run a generator
that will produce electricty- the venting system can be piped to the generator.