The thermal waste utilisation plant operated by EVN originally had an annual throughput capacity of about 300,000 metric tons, which has since been increased to over 500,000 metric tons per year. About half of this volume is household and bulk waste from Lower Austrian households.
The key object of incinerating waste is to render harmless those substances contained in everyday products which turn into pollutants at the end of their life. For organic pollutants this can be achieved by incinerating them at high temperatures in excess of 1000°C, while inorganic pollutants such as lead, cadmium, fluorine are extracted from the materials cycle and dumped in a manner that does not harm the environment.
One ton of waste, when incinerated, yields 250 kg of slag and boiler ash, 30 kg of scrap iron, a filter cake that weighs 1 kg and about 30 kg of filter ash. An additional product is gypsum (5 kg) which is used by the building industry.
Dumping the slag and boiler ash on a landfill for inert materials creates no problem. In some countries (such as Germany and the Netherlands), the slag is even used as gravel for road construction.
The filter cake from flue gas cleaning and the filter ashes contain, in high rates of concentration, all pollutants which cannot be destroyed even at temperatures in excess of 1000°C. They are deposited in special underground dumps below groundwater level or admixed with cement to make them non-elutable and dumped above-ground.
An essential point in favour of the method is the fact that, compared to untreated waste, incineration significantly cuts the volume ultimately needed for dumping and thus also the space required for such dumps. What is finally dumped consumes just 10% of the space initially taken up by the waste.
