Incineration of Waste
Author: Dr Sibbele Hietkamp ~ Senior scientist, CSIR
( Article Type: Explanation )
The incineration (high-temperature burning, using sophisticated high-tech equipment) of wastes, particularly non-recyclable municipal waste and a variety of industrial and hazardous waste, is practised in many countries, largely in Western Europe. In most cases incineration plants include cogeneration technology, whereby the heat of combustion is also used for electricity generation and/or heat recovery. One of the other advantages of incineration is that this process typically reduces the amount of waste volume by 80 or 90% and destroys a large variety of hazardous chemicals including persistent organic pollutants (POPs).
The alternative to incineration is normally land filling, which has a number of disadvantages, including a large space demand. Typically leachate is also produced in landfills, which, depending on the source of the waste, can be very hazardous to humans and nature. Often special treatment of the leachate is required. Persistent pollutants can also be retained for a very long time period in landfill sites and can be released at any time in the future if development of the landfill site should ever take place. Land filling is preferred in countries where the cost of both land and of waste disposal by landfill is low.
In many countries, including South Africa, public opinion is generally against incineration of waste. Many environmental NGOs share this opinion. There are several reasons for this, ranging from idealistic to more pragmatic. In the first category falls the thinking that wastes and specifically hazardous wastes should not be produced at all. In the second category, however, it is recognised that in the past some incinerators were built cheaply, operated poorly and caused unacceptable hazardous emissions. The public and NGO reason for opposition to incineration is that in their opinion it is not possible to guarantee that hazardous emissions would not be emitted in the future.
It is my personal opinion that for certain types of wastes including waste solvents, waste oils, POPs and infectious waste there is no good alternative to incineration. However, it is necessary to ensure that incinerators are designed correctly for adequate destruction and removal efficiency and are equipped with gas cleanup systems that remove potentially hazardous emissions to a level that can pose no risk to nature or humans. Furthermore, the operating staff must be well educated and must keep records of crucial operating parameters. Lastly, appropriate continuous stack monitoring is required to ensure that the plant is operated according to specifications.
