Cyprus context
These are not stand-alone pages, but
complements to the above ones.
|
|
There seems little doubt that waste which cannot be recycled in
traditional manners is best used for generating energy. There are
several ways of doing this but it is probable that the oldest way is the
best, at least with modern implementations. This consists of
incinerating the rubbish and using the heat to either generate
electricity or using it for industrial purposes or for the central
heating of buildings.
Historically, it is unknown when this idea was first implemented. Amsterdam
built an incinerating plant which generated steam, sent to a neighbouring power
station, as early as 1919; however, the power station existed prior to the
incinerator, so that it was not a complete waste-to-energy plant.
It is unknown when the first purpose-built power station designed for burning
garbage was implemented, but it seems probable that it was built in Paris in the
early 1920s. Unfortunately, like the garbage incinerators built in Nottingham in
1874 and New York in 1885, there was no treatment of the flue gases which were
very unpleasant and probably dangerously polluting. There is little doubt that
very few such power stations were built before the Second World War.
Today, many garbage incinerator power stations are operating throughout the
world, especially in Japan and France. Unfortunately, problems with some of the
French installations have given them a rather bad press, exploited strangely by
the so-called environmental NGOs who have systematically opposed all new
installations of the type. This has been because of the fear generated by
dioxins. This has become a dirty word since the Seveso disaster in Italy where
an escape of chlorodioxins used in the manufacture of pesticides caused the
evacuation of a village. However, the NGOs seem to confuse chlorodioxins with
dioxins which, although toxic, do not provoke the chloracne symptoms of
chlorodioxins. Notwithstanding, there are very severe regulations limiting the
emissions of dioxins and chlorodioxins to such levels that there is no risk of
any harm whatsoever.
Another error which the NGOs propagate is the fact that these power stations
emit carbon dioxide. This is perfectly true but, as the incinerated garbage is
organic, mainly kitchen refuse, it is a renewable biofuel in exactly the same
way as burning used cooking oil in a diesel car. In any case, if the same
kitchen refuse were sent to a landfill, the emissions of methane would be far
more disastrous as a greenhouse gas. Sometimes, I despair of the lack of logic
that these organisations pretend to offer to the general public.
Modern household garbage incineration plants produce virtually no negative
effects for neighbouring communities. The incoming waste is stored in a silo
above which the air is evacuated to assist the incineration. There is therefore
no smell or dirt from this part of the plant. After the steam is generated, and
the flue gases have the solid matter removed by electrostatic precipitators,
followed by scrubbers and catalytic converters. The resultant gases in the stack
typically at about 1/10 of the level permitted by the most rigorous regulations
for pollutants and are constantly monitored. The heavy metals are recovered for
recycling. On the contrary, there are distinct positive effects offered to the
neighbouring communities. These include employment and space and water heating
of houses and apartments.
Besides incineration, there are a number of other ways whereby garbage may be
transformed into energy. Most of these have an overall efficiency lower than
that of incineration. However, not all kinds of waste lend themselves readily to
incineration. For example, large-scale poultry farming produces vast quantities
of feathers, chicken heads and entrails and other parts which, overall, approach
90% water. These do not burn readily but, if heated in a reactor under given
conditions, can produce a combustible mixture of gases. Part of this gas is used
for the heating process while the rest is burnt to recover as much energy as
possible. The overall efficiency of this method is lower than that of
incineration, counting the useful energy produced per unit weight of the waste.
The same method could be used for household garbage, still with a lower energy
efficiency, and with a greater volume of solid waste. It would have the
advantage that the cost of flue gas treatment would be somewhat lower.
Another method which is often promoted is collecting the gas from landfills
in which household garbage is dumped. This gas is combustible, consisting of
methane with some carbon dioxide. However, the amount of energy recovered by
this method is very small compared to that of an efficient, modern incineration
plant.
In 2007, I visited Tridel, an ultramodern waste to energy power plant in
Lausanne, Switzerland. This visit was an eye-opener and I was very impressed
by the technical performance, as well as the cleanliness and freedom from
smell. This plant needs the most rigorous standards for air and water
pollution with large margins of safety. You can read all
about my visit here.
|