Environmental Engineering Reference
In-Depth Information
FIGURE 9
Flow diagram for Kalundborg industrial ecosystem. (Hardin Tibbs)
and the city of Kalundborg. Rather than burning off surplus gas, the refin-
ery now sends it to the power plant and the plasterboard factory, which use
it as a fuel in their production processes.The refinery also sends excess cool-
ing water and wastewater to the power plant to help it meet its cooling
needs and turns waste sulfur into sulfuric acid, which it sells.The power sta-
tion, in turn, sells waste steam to the city, the biotech company, and Statoil
for heating.This has allowed the city and the Danish government to replace
about 3,500 air-pollution-emitting oil furnaces. By developing a way to use
salt water from the local fjord for some of its cooling needs, the power sta-
tion reduced its withdrawals of fresh water from nearby Lake Tisso. It sends
the resulting water waste by-product, hot salt water, to a local fish farm.The
power plant also processes waste SO
2
into calcium sulfate (gypsum), which
it sells to the plasterboard company. It sells its desulfurized fly ash to a
cement company. The biotech facility, in turn, sells sludge from its manu-
facturing process to nearby farms for use as fertilizer. This web of waste
exchanges has benefited the firms involved by lowering their costs and cre-
ating new revenues. It has also reduced air, water, and land pollution in the
region.
13
The industrial ecology concept also encourages waste minimization
through design for environment (DFE). Instead of focusing on designing
end-of-pipe systems for treating air and water pollution, industrial ecology
