Since 2005, a ban on the disposal of untreated waste in landfills has been in place throughout Germany. Other means of waste processing are therefore required to keep the huge amounts of waste produced in Germany under control. In addition to waste avoidance, reuse and recycling, the thermal treatment of residual waste by means of incineration plays a key role in closed-loop recycling management. This method goes beyond simply incinerating the waste and instead ensures that harmful substances are destroyed during the incineration process and therefore never released into the atmosphere. At the MHKW Rothensee, continuous measuring systems ensure that the plant reliably complies with the legally stipulated values at all times and provide information on pollutant concentrations. The recorded values are transmitted to the responsible regulatory authority via online data transmission. With this approach, the MHKW Rothensee waste-to-energy plant makes an extremely important contribution to environmentally friendly waste disposal. It also separates reusable materials such as ferrous and non-ferrous metals from the residue from the incineration process so that they can be reused. The remaining slag is then used as construction material.
We dispose of
1 million tons
of waste per year.
The emissions of the MHKW Rothensee are measured continuously and monitored by the responsible regulatory authority. The flue gases are extensively cleaned and filtered to ensure that the air discharged from the MHKW Rothensee is clean. Furthermore, climate-relevant carbon dioxide emissions will soon be treated with a method that binds the carbon dioxide and prevents it from being released into the atmosphere.
The MHKW Rothensee complies with the requirements of the German Federal Emission Control Act in exemplary fashion. In fact, some of its emission values are well below the legally stipulated limits.
Threshold values of the 17th German Federal Emission Control Act (BImSchV)
The company Müllheizkraftwerk Rothensee GmbH has been using an energy management system certified according to the standard DIN EN ISO 50001:2018 since January 2017. By implementing this energy management system, the MHKW Rothensee undertakes to continuously reduce its energy consumption and resulting CO2 emissions in a sustainable manner while observing statutory requirements. It also requires its employees, partners and service providers to commit to handling energy and natural resources responsibly in their processes and when manufacturing and supplying products. Energy management forms part of the integrated management system of the MHKW Rothensee, which already contains quality management and certification as a waste management company.
The MHKW Rothensee uses a modern flue gas cleaning system to ensure that pollutants are reliably filtered out of its flue gases and that the gases are clean when they leave the plant.
The formation of certain pollutants such as dioxins or furans is already prevented in the combustion chamber, which is designed to maintain a temperature of at least 850°C after the last supply of combustion air in compliance with the requirements of the 17th German Federal Emission Control Act (BImSchV). Oil burners that are automatically activated when required ensure that this minimum temperature is observed.
An ID fan in front of the chimney generates negative pressure throughout the entire system, causing the flue gases to be sucked out of the boiler and moved through the system.
The main flue gas cleaning work is performed by two key components: The spray absorber pre-separates harmful acidic gases and cools the flue gases, while the fabric filter collects flue dust, salts, heavy metals and any remaining organic pollutants.
To ensure that the harmful gases can be separated from the flue gases, lime milk from the lime milk treatment system is injected into the spray absorber automatically or in a controlled process, and slaked lime is added to the diversion reactor. Lignite coke (HOK) is also added to the diversion reactor to bind and separate all other pollutants before being separated in the fabric filter.
The pollutant concentrations in the pure gas are continuously measured and monitored, and the recorded data is transmitted online to the competent regulatory authority.
The 650,000 tons of waste processed in the MHKW Rothensee every year not only generate energy for electricity and heat but also produce around 180,000 tons of slag, boiler ash and residues from flue gas cleaning. What happens to the residual material? It has long been recognised that mineral mixtures such as slag are valuable, important and ideal for reuse. The idea of reusing residual material therefore played an integral role in the overall concept of the MHKW Rothensee right from the word go.
All slag is processed and reused: valuable metals are salvaged from it and the slag is used to produce sought-after construction materials for road and controlled landfill construction.
Boiler ash and filter dusts, for example, are used to reinforce and fill old tunnels in potash mines. The MHKW Rothensee works with a number of competent partners to ensure the reliable reuse of its residual material.
The permanent negative pressure in the waste bunkers ensures that no odours or gases can escape.
Noise or sounds are also unable to be heard from outside because the entire waste recovery process takes place in a closed, soundproofed system.
