For the countries of Europe, the new PARCOM limits require
many industries to achieve optimised waste water
management. The lowering of concentration limits for
several pollutants requires a change in waste water
In the Belgian company STC N.V. the waste water treatment
installation has to be rearranged. The new technology has
to fulfil several requirements, namely:
* be able to clean different waste streams at the same time
* the treated water must be dischargeable at any time in
such a way that none of the concentration limits is
* avoid transport and external treatment of some
concentrated waste waters.
* be technically, economically and ecologically feasible.
This can be achieved with "vacuum evaporation". The energy
for the evaporation will be generated in a so-called
co-generator, where natural gas is transformed into
electricity and a defined volume of hot water. This hot
water is used to bring the waste water up to a reduced
boiling point (30 deg.C). The excess electricity can be
sold or used within the company.
The implementation of a "vacuum evaporation" technique, is
the final goal of this project. The evaporation technique
has several advantages in comparison with conventional
environmental technologies: no waste water discharge, rinse
water recycling, production of electricity, strongly
reduced solid waste disposal (drying of sludge), chemical-
free technique, environmental legislation is no longer a
problem because there are no concentration limits to
consider, the technology complies with the PARCOM
requirements (reducing and avoiding waste, recovery of
valuable products) and is suitable for the treatment of all
kinds of waste water.
The evaporation technique is not new. What is new,
however, is the forward-looking application which makes it
possible to produce energy and recycle rinsing water. On
the other hand, the technology can purify all waste water
streams in such a unique way that "zero waste water
discharge" is obtained.
Keywords: environment, waste water discharge, vacuum