More about Wijster
What ultimately remains is the fuel for our plant’s three incineration boilers. The temperature on the boiler grid is between 1,000 and 1,100 degrees. Steel pipes through which water flows are incorporated in the walls of the thirty-metre high boiler. There are also pipe clusters high up in the boiler. The heat converts the water in those pipes into steam, which is then conveyed with great force along the turbine’s eighteen paddle wheels. These turn a shaft connected to a large dynamo: the generator. That supplies enough electricity for 100,000 households. This form of energy generation saves more than 70 million cubic metres of natural gas a year.
Since mid-2011 we have been supplying a portion of the steam produced as process steam directly to a company at the adjacent industrial site: Energie Transitiepark Midden Drenthe, which uses the heat for its production process. The direct use of heat as a power source is more energy efficient and generally is more valuable than using steam solely to generate electricity.
Flue gas cleaning
The released flue gases are cleaned in a number of steps at our plant in Wijster. This enables us to operate well under the strict European standards for waste incineration. The Wijster waste-to-energy plant is amongst the cleanest in the world. Cleaning flue gases yields a limited amount of remnant material: ash particles and flue gas cleaning residues. The trapped flya sh and boiler dust are used as filling for closed slat mines in Germany. The composition of the flue gases is automatically controlled. Besides that, we also biomonitore the effect of incineration in the surrounding area. Under controlled conditions we cultivate vegetables and have samples checked every two weeks.
Our efficient plants are also well equipped to recycle the final remnant of the waste incineration process: bottom ash, also known as slag. Following the waste incineration process, we treat the bottom ash to separate out ferrous and non-ferrous metals in a specialised bottom ash treatment facility. These metals can be reused in the metal processing industry. The remaining ash is then upgraded into a certified building material for building roads, elevations and sites.