Incineration is one of the
methods of waste management that is quickly taking a prominent role for
municipal authorities all over the world. The advantages and disadvantages of
incinerators have to be properly debated before installing such systems.
Prevention of waste is at the
top of the list as far as waste management techniques are concerned, but as
this is humanly impossible for us humans with the lifestyles that we are used
to, the next best is the recycling and reuse of materials. While this may not
yet be very prevalent in developed countries, many developing countries
practice this method because of the economics of recycling and reuse which
gives incomes to the underprivileged strata of people in the business.
Incineration with recovery of
energy is considered the best method of waste management and ranks over plain
incineration and landfill. Landfills are the most commonly practiced form of
waste management, but the huge requirements of land and the fact that such
landfill adds to pollution of groundwater and air by the formation of leachates
and gases have made city managers wary of this method. Even with incineration,
some quantity of waste is produced but this is reduced to just 10 percent of
the original waste.
So in effect incineration is
considered a very effective method of waste management. What then are the
advantages and disadvantages of incinerators?
Incineration is a practical
method of disposal that saves a lot of money on transport of waste to landfills
and thus also the carbon footprint that such transport leaves behind. The sheer
reduction in the space required to dispose of the 10 percent of waste that it
does produce relieves pressure on land, which in urban areas can constitute a
big saving. Landfills have never been a pretty site and also give rise to a lot
of pests and insects. An incinerating plant will look like any other industrial
structure. Waste to Energy (WTE) incinerating plants have a huge advantage that
they can produce electricity which in the long run can help to reduce costs. A
250 ton per day incinerator can produce 6.5 megawatts of electricity per day
and this itself can save about $3 million per year. Some cold countries also
use the heat from incinerators for heating of offices and houses in locations
near the plant.
Gases and leachates that are
produced in landfills by waste are totally eliminated and the waste that is
produced in the incineration is totally free of any environmental risk. In fact
there are efforts to convert even this waste to other materials.
The high cost of incineration
plant has been a turnoff of for municipal authorities and is only now being
addressed with the introduction of WTE plants. The need for huge waste to
incinerate has led to abandonment of other plans for recycling and reuse of
waste. Dioxins are produced in the treatment and is a cancer forming chemical.
These are produced in the smoke stack. The plants require skilled personnel for
operation and continuous maintenance.
In the process of
incineration, incinerators reduce the waste by burning it after the incinerator
is initially fired up with gas or other combustible material. The process is
then sustained by the waste itself. Complete waste combustion requires a
temperature of 850º C for at least two seconds but most plants raise it to
higher temperatures to reduce organic substances containing chlorine. Flue
gases are then sent to scrubbers which remove all dangerous chemicals from
them. To reduce dioxin in the chimneys where they are normally formed, cooling
systems are introduced in the chimneys. Chimneys are required to be at least 9
meters above existing structures.
The advantages and
disadvantages of incinerators need to be weighed carefully by any civic
authorities considering this as an alternative. WTE plants are gaining
more favor and the designing of
incinerators is being constantly evolved to increase efficiencies and reduce
production of dioxins.