Environmental Engineering Reference
In-Depth Information
minimal disturbance of the natural conditions at the site. Today, these extensive
remediation technologies, often in combination with ex situ techniques such as
removal of the source, are widely accepted. As specific applications, 'bio-screens'
are used; these are zones with an active, often stimulated, degradation at strategic
positions in the soil system, or Funnel-and-Gates techniques, in which contaminants
are led to zones with an active degradation. The basic principle is: 'use the natural
self-cleaning capacities of the soil as much as possible, stimulate natural conditions
when necessary and use ex situ remediation technologies only when strictly needed'.
1.8.5 Market-Oriented Approach to Site Development
Construction work, certainly within urban areas, is big business. Ironically, most of
the interesting locations for residential developments often coincide with contami-
nated sites. Several former industrial sites, which were created close to the former
limits of the municipality, now lie within the expanded cities. These sites, although
often contaminated, offer excellent possibilities for residential development. Other
examples for residential development are former harbour sites, and former water-
front storage depots or warehouses, which offer exclusive housing and recreation
opportunities. Again, these sites are often contaminated. An interesting adage from
site contractors involved in building activities such as developing residential areas
is: 'turn a threat into an asset'. Risk Management of contaminated sites in these areas
could result in a profitable rise in value of the site for different building purposes.
Moreover, consultancies have proven to be experts in finding creative solutions for
risk reduction.
More and more it has become accepted fact that contaminated site management
is part of the integral complex package of site development (see Fig. 1.12 as an
example, which shows a former with DDT (DichloorDifenylTrichloorethaan) and
HCH (HexaChloroCyclohexane) contaminated site in Wuxi, China, which has been
developed into a residential area after remediation). Traditionally, contractors had
to adapt the physical state of a site through grading, providing drainage and guaran-
teeing the supporting foundation of buildings by the use of piles. One could argue
that maybe contaminated site management is just another aspect of making the site
suitable for building activities. Contaminated site management is just another aspect
that should be included in a cost-benefit analysis. As a consequence, market-driven
financing is contributing more and more to solving the problem of contaminated
sites.
The development of a more market-oriented approach has gone hand in hand with
the mentality change towards a more flexible way of contaminated site management
and a more intensified use of Natural Attenuation techniques (Section 1.8.4.2 ). As
a consequence, 'the market' has taken on the responsibility for a cost-efficient risk
reduction at many contaminated sites.
Schelwald-Van der Kley et al. ( Chapter 24 of this topic) describe the philosophy
on cost-efficient Risk Management solutions of industrially contaminated sites, at
the same time discussing the protection of human health, ecology and groundwater.
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