Environmental Engineering Reference
In-Depth Information
Fig. 20.9
Aerial view of the Volgermeerpolder site
27
The aim is the gradual development of a bog in the area. A wider sustainability ben-
efit of this bog development is the creation of a 100 ha carbon sink. The area will
also be suitable for recreational purposes, and will provide valuable habitat area.
20.5.2 Wind Powered Passive Aeration Remediation Systems
Wind energy can be converted to electrical energy which could power a remedi-
ation process. However air itself is a medium that consists of the most elemental
parameter to enhance aerobic biodegradation, oxygen. Using the energy from wind
to inject air into the soil is a very efficient method to enhance aerobic bioremedia-
tion. The energy from wind can be applied to inject air into the unsaturated upper
soil (
venting
) with moderate to high hydraulic conductivities. However, the over-
pressure that can be created is generally insufficient to inject air in the saturated
zone (
sparging
).
Wind powered turbine ventilation systems have been applied to the in situ aerobic
degradation of petroleum hydrocarbons. For example, at site in the Netherlands,
Tauw, found that residual soil contamination with a light petroleum hydrocarbon
fraction remained after excavation of the major sources (unpublished information).
The residual contamination was present in the unsaturated upper soil layer. The
subsurface consisted of moderately coarse sands with a hydraulic conductivity of
3-5 m/day. The vadose zone was aerated by a wind powered turbine system, using
equipment generally applied to indoor air ventilation in houses (see Fig.
20.10
).
Other passive venting systems that can be used are based on differences in
barometric pressures (see Fig.
20.11
for a passive soil venting system tested
27
De Jong Luchtfotografie (2009)
www.dejongluchtfotografie.nl
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