Environmental Engineering Reference
In-Depth Information
quality of drinking water and human health, drinking water quality standards are set by
the regulatory bodies for most, if not all, of the countries in the world. As discussed in
Section 3.3.1 in Chapter 3, the main parameters usually monitored for drinking water are
BOD, color, turbidity, N, P, suspended solids, odor, heavy metals, VOCs, pesticides, bacte-
rial level (such as coliform forming units, CFU), and perhaps other microorganisms. We
should note that infectious diseases caused by pathogenic bacteria, viruses, and protozoa
in drinking water are by far the greatest health threat.
Although these national standards set the basis for the water quality for the various
countries, production of a national drinking water quality index for each and every coun-
try will require considerable effort in developing the relationships and weighting func-
tions. To a large extent, this is because of the risk-beneit approach adopted by many
responsible authorities in articulating quantitative values for the parameters chosen for
monitoring. The risk-beneit consideration is not economically driven, at least not directly.
Rather, it is driven by the need to provide acceptable drinking water to the most people
without endangering public health. Setting standards that may be considered “too strin-
gent” may on the one hand be prudent and safe, but on the other hand may make drinking
water unavailable to a large percentage of the population—especially in regions of water
deprivation. Because of these kinds of factors, development of drinking water quality indi-
ces becomes more than a challenge.
13.5 Sustainability Practice Examples
We will look at some case studies in this section. These are cases demonstrating sustain-
able practices and the implementation of methods to evaluate the sustainability of a project
or process with regard to the geoenvironment. At least one case study is presented for each
of the sectors, urbanization, resource exploitation, food production, industrial develop-
ment, and the marine environment.
13.5.1 Rehabilitation of Airport Land
Between 150,000 and 350,000 m
3
of soil in the contaminated site needed to be remediated at
a former Norwegian airport (Ellefsen et al., 2001). A method was used to incorporate envi-
ronmental effects into an evaluation of different remedial options. The environmental costs
and beneits were determined, which became part of the decision assessment. One of the
main environmental targets was the reuse of the treated soil for landscaping. Asphalt and
concrete would also be reused. To perform the assessment, a model developed by the Danish
National Railway Agency and the Danish State Railways was utilized. A life cycle approach
for the remediation was used. Consumption of materials, fuel and energy, effects of noise,
odor, and other annoyances to humans, and emissions to air, soil, and water were calculated.
The site (including soil and groundwater) was contaminated with diesel and heating oil
between 3.5 and 5 m below the surface due to leaking storage tanks and runoff water. Free
phase oil was also found. Two remedial options were chosen and compared. They were
(a) excavation followed by biological treatment and (b) in situ treatment by biosparging
and removal of six tanks.
Energy consumption for the excavation option was found to be ive times higher than
the in situ procedure. Additionally, emissions of greenhouse gases were estimated to be
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