Incineration can lead to a huge waste of important and finite natural resources which literally go up in smoke or end up as part of the resultant ash. Unless important resources such as all metals, plastics, and glass are removed before incineration this process can result in loss of resources which causes negative knock on environmental effects in the form of increased mining to replace those lost resources, and increased energy use to process and produce new resources. Increased mining leads to further land pollution and degradation of the land environments which are being mined. Increased energy use means increased fossil fuel use and therefore further increases in greenhouse gas emissions.
Incinerators destroy reources which could easily be recycled. The use of incineration to deal with waste can also be a disincentive to use and promote recycling schemes and to compost organic household waste at a municipal level. This issue can be further exacerbated by the fact that the high costs of building an incinerator need to be offset with long contracts with municipal authorities to burn local waste or waste from other regions. These long contracts can encourage more incineration of waste locally rather than recycling.
The location of an incinerator is often very controversial and most residents do not want one situated near to them. The problems they can bring include increased traffic to an area, which is specifically carrying waste for processing at the incinerator plant, a problem made worse if waste is imported from other regions. This itself is associated with unpleasant smells and an adverse effect on local land and house prices. This latter effect could just be perception, but who wants to relocate to an area which has a waste incinerator nearby? So incinerator locations are often very restricted and plans for new ones can become political hot potatoes.
Even though modern incinerators use filters and processes to remove many of the harmful particulates and toxins from the hot flue exhaust gases produced as a result of the incineration process, they still do not filter out the smallest particles,. These particles could cause health problems in areas that are exposed to their emission downwind, with ongoing research seeking to establish the exact effects. Many of these tiny particles do not have any air quality standards or regulations attached to them which basically gives incinerator companies freedom to emit without consequence. The toxic fly ash which is prevented from release into the air environment by the filtration process also has to be dealt with (see below). Pollutants can still escape the system into the air resulting in toxic heavy metals like Cadmium being dispersed into surrounding ground and water environments. The issues relating to heavy metal release into the environment was discussed on the Ecoants page on land pollution in our batteries section. Dioxins too can escape. These compounds can be carcinogenic and have other detrimental effects on human health.
A further problem with incinerated waste is what to do with the resultant ash that is collected. Part of this ash, the filtered fly ash, contains a significant proportion of toxins such as heavy metals. In this ash form, if they are not dealt with correctly and sealed into water tight containers, they can leach into the surrounding environments where they are placed and cause both health and environmental problems as a result of their toxicity at increased levels. The ash at the bottom of the incinerator can also contain some toxins, including the presence of heavy metals, so this too has to be stored appropriately to prevent contamination of fragile environments.