Urbanization and the Geoenvironment - Sustainable Practices in Geoenvironmental Engineering - page 248

York, 2013). Storm water management and reduced water and energy consumption are
practiced. As 90% of the wetlands in New York-New Jersey Harbor Estuary were lost,
an effort is underway to restore the wetlands. The process consists of using goats to
graze on invasive species and installing biodegradable coir (coconut iber) iber logs
with mussel shells and native wetland plants to reduce erosion and dissipate wave
energy. Freshkills Park played a role in absorbing and slowing Hurricane Sandy in
2012 (Kimmelman, 2012).
7.5.1.2 Vertical Barriers and Containment
In Chapter 3, we have seen how vertical barriers can be used to isolate and contain the
contaminants in groundwater. When a landill is in contact with the groundwater or
when a landill leachate contaminates the groundwater, an available treatment option is to
install vertical barriers to conine the contaminants. A low permeability base is required
to key in the cutoff walls. If this does not exist, an artiicial base will have to be added. For
older landills where liners have degraded or do not exist, other means may be required
to reduce the potential for contaminant leaching into the groundwater as shown in Figure
7.13. Silicate gels, pozzolanics, or cements can be injected into the soil under the landill to
form an impermeable layer, thus immobilizing the plume. Groundwater levels may also
need to be lowered by pumping to maintain their level below the landill and the seal-off
area. Pump and treat systems for treating the groundwater may also be necessary. Land
Nest of monitoring wells
Contaminant plume
Wastepile
Injected low
permeable layer
Groundwater
FIGURE 7.13
Vertical barriers and injections for an artiicial low permeable layer under a landill. (With kind permission
from Springer Science+Business Media: Urban Land, Degradation, Investigation and Remediation , 2003, 331 pp.,
Genske, D.D.)