Cyprus context
These are not stand-alone pages, but
complements to the above ones.
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Because industrial waste falls under many categories, there is no
simple answer as to how it can be treated. Much of it is very hazardous
to the environment and disposing of it can be a real headache, but it
must be done correctly. Unfortunately, in many places, help is not
easily forthcoming. I propose to offer a few words about each of the
major categories.
Scrap metal: nearly all mechanical workshops have some form of scrap
metal. It is all valuable but only if it is sorted into separate bins for
each type of metal. As appropriate, these should be for iron and steel,
stainless steel, aluminium and alloys, copper, brass etc. Obviously, iron
and steel have a relatively low value compared with the nonferrous metals.
It is therefore wiser to wait to accumulate sufficient quantity for a scrap
metal merchant to be interested, perhaps several tonnes. For the nonferrous
metals, which have a much higher value, it is interesting for as little as
100 kg.
Scrap plastics: like metals, plastics should be sorted into separate
categories for each type. If large quantities are generated in a single
colour, then this is preferable as a separate item. The most valuable
plastics polyethylene terephthalate (PET), followed by high density
polyethylene (HDPE). Any scrap plastics that cannot be categorised are best
incinerated in an installation fitted with scrubbers. Under no
circumstances, should plastics be burnt in open furnaces or fires. In
particular, halogenated plastics, such as PVC or PTFE, produce highly toxic
and polluting fumes when burnt. Modern waste-to-energy plants willingly
accept all types of plastic.
Oils: lubricating oils and cutting oils can be added freely to the fuel
used in modern cement factories, fitted with scrubbers. The only proviso is
that water soluble cutting oils do not burn. In some cases, it may be
possible to add these to the same fuel, subject to approval of the factory.
This is because the oils in the cutting oils may be selectively dissolved by
the fuel oil, allowing the water to drain to the bottom of the tank, fitted
with a drain tap. However, if the tank is made of steel, it may cause rust.
In this case, it would be up to the machine shop to ensure that the cutting
oil residues were dehydrated.
Solvents: alkane solvents, such as kerosene, and aromatic solvents, such
as acetone, as well as alcohols, may be treated in a similar manner to oils.
Halogenated solvents, such as trichloroethylene, n-propyl bromide,
hydrofluorocarbons etc., are more difficult because they are not
combustible. Small quantities, not exceeding 1%, may be added to cement
factory fuel, subject to the owner's approval, provided that the plant is
equipped with a high-quality scrubber to remove the halide gases.
Paper: most factories produce large quantities of paper and cardboard,
including from the offices. These can usually be recycled. Any paper
unsuitable for recycling, such as impregnated with grease, should be
incinerated in a waste-to-energy plant. Some recyclable paper may contain
confidential information which, even shredded, entails a risk which the
factory may not wish to take. It was seen in the Enron affair that shredding
is not 100% reliable as a means of protecting data. Paper such as this
should be confided to specialist companies there to keep it in locked
security boxes, which are unlocked only in the presence of selected
personnel who place the papers directly into the incinerator hopper.
Aqueous chemicals: this is probably the most difficult category of waste
to treat because of the enormous range of different chemicals. Specialist
companies will handle this hazardous waste, at a cost. The important point
is that the container for each type of chemical must be clearly labelled as
to its contents. Two different kinds of chemicals should never be mixed, for
fear of violent reactions or even explosions. Without the proper equipment
and training, used chemicals can rarely be recycled within small companies.
Solutions containing precious metals, such as gold and platinum, are
accepted and paid for, according to the precious metal content. Solutions
containing large quantities of single heavy metals can also sometimes be
sold, depending on the market demand. Companies producing large quantities
of metallic solutions, such as electroplaters, should have their own waste
water treatment plant which will ensure that the waste water produced
conforms to local regulations.
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