Environmental Engineering Reference
In-Depth Information
CHAPTER TWELVE
The microbial ecology of remediating
industrially contaminated land: sorting
out the bugs in the system
KEN KILLHAM
Introduction
Understanding and manipulating the microbial ecology of contaminated land
are increasingly critical steps towards meeting the challenge of remediating
the considerable legacy of industrial pollution in the UK and worldwide.
Understanding the microbial ecology of contaminated land is key to its
remediation in two ways. First, the microbial community in the soil, occasion-
ally enhanced through inoculation, can be exploited to bioremediate (through
either in situ or ex situ approaches) contaminated sites (Alexander
1999
; Atlas &
Philp
2005
). This is an increasingly attractive, environmentally sustainable
option as excavation and landfill of contaminated site waste become both
increasingly expensive (both through landfill tax increases, ever-increasing
transport costs and the introduction of the aggregrate levy on material
brought in as fill), fewer landfill sites are available (in Scotland, for example,
there are no hazardous landfills and material must be transported great
distances, further adding to disposal costs) and environmental regulators
rightly press for more sustainable approaches to site clean-up. Second, the
indigenous microbial communities of sites are often impacted by the contam-
ination, particularly where toxic contaminants such as free phase solvents and
available heavy metals are present, and part of the remediation challenge is to
restore soil/aquifer biological function. Because of the wide range of microbial
functions carried out in the soil, in particular, this restoration may be linked,
for example, to carbon and nutrient (N, P and S) cycling or to the wide range of
plant microbe interactions on which ecosystem health depends.
In this chapter, two aspects of the microbial ecology of remediating industri-
ally contaminated soils are considered:
Key soil bacteria, such as those involved in the biodegradation of organic
contaminants and in key soil functions, have been selected for construction
