Thanks to growing environmental awareness, waste is increasingly being separated and recycled. However, residual waste always remains that can't easily be recycled. This ends up in waste incineration plants (referred to as KVAs in Swiss German) for disposal and reclaiming, such as the KVA Linthgebiet in Niederurnen in the Swiss canton of Glarus. Due to the strict environmental specifications which the plants need to meet, they need reliable and precise chemical analysis which informs the operators what is present in which quantity in exhaust air and waste water.
High-tech waste recycling
Walk into the control room of the KVA Linthgebiet plant and you’d think you’d stumbled on to the set of a science fiction movie. In front of a concave wall peppered with control monitors and LEDs is a semicircular desk with computer screens positioned on it (Figure 1). Of the 40 staff members who work at the plant, a handful are here in the “cockpit” manning the controls – observing and deliberating, and monitoring the countless processes taking place in the plant. The KVA Linthgebiet plant disposes of municipal waste produced by the cantons of Glarus, Schwyz, and St. Gallen, as well as industrial waste. Incinerating waste is by no means its only task, however: it is also a recycling plant that recovers nonflammable components (both scrap iron and nonferrous metals) and generates current and district heating from the waste heat created by the incineration process.
It’s all in the mix
A glass bay protruding from the control room, opposite the cockpit, houses another staff member in blue working gear. Here, this person has a view over the waste bunker – where garbage is stored temporarily after it is delivered – and operates a grab crane with a giant claw that he uses to transfer the waste to the furnace. He also mixes the garbage; this prevents contaminant levels reaching excessively high peaks, something which could put too much strain on the plant and result in lasting damage. If a load contains fluorinated plastics, for instance, hydrogen fluoride will be produced during incineration, followed by corrosive hydrofluoric acid in the subsequent wet flue gas purification process. While installations are able to withstand this acid in small quantities, they run the risk of damage if persistently high volumes of it are released.