Uponor delivers tanks for a pioneering development project at incineration plant
The circular economy, recycling and sustainability are keywords in the Uponor mission. Uponor will take part in projects that make a difference to people, society and the environment. That is why Uponor is proud to have delivered tanks to a new facility at Vestforbrænding, which converts toxic fly ash into recyclable materials using the Halosep technology.
In Denmark we burn waste to create energy. It is an old tradition to combine the incineration of non-recyclable waste with energy production. When waste is burned in large furnaces, it creates hot smoke which heats up water.
The steam drives a turbine and generates electricity and the hot water is also used for district heating.
Vestforbrænding is Denmark’s largest waste company. Ever year the waste incineration plant in Glostrup burns 500,000 tonnes of waste for the benefit of the 80,000 people in the area who receive electricity, and the 75,000 households which receive district heating.
When you burn waste you create energy and electricity, but also a very dangerous residual product in the form of ash, called fly ash. In particular, the ash’s toxic salts and heavy metals make it hazardous to humans and the environment. Therefore, – according to EU rules – fly ash must be deposited in special secured landfills within or outside EU borders. Vestforbrænding alone deposites a total of 15,000 tonnes of toxic fly ash each year.
But now it is no longer possible to send large quantities of hazardous waste out of the country. Instead, pioneering technology is to remove the dangerous elements from fly ash, so that the ash goes from being hazardous to harmless. That technology is called Halosep, and was invented between 2003 and 2007 by the Danish company Watech. Halosep was later bought by the Swedish operation Stena Recycling, which has developed the technology and tested the process at smaller experimental plants. Now, together with Vestforbrænding, Stena Recycling has built the world’s first full-scale Halosep plant, putting the technology into practice.
- Glostrup, Danmark
- Färdigställt: 2020
- 10 tanks Ø3000mm, 3 tanks Ø2400mm, 1 tank Ø2000mm and 3 minor tanks
Zinc, lead and cadmium can be disposed for recycling in several places within the industry sector, and the salt has become so pure it can be used as road de-icer
At the Halosep plant the hazardous fly ash, together with scrubber fluids from the flue gas purification, is converted into non-hazardous ash and recyclable materials. This means that much less toxic waste has to be transported to landfill in the future. In the Halosep process, 80% fewer chemicals are used than were previously utilised to treat fly ash and scrubber fluids. This benefits the environment. But the revolutionary thing about the Halosep process is not only that you can now clear the fly ash of toxic substances with fewer chemicals, but also that the substances which are removed from the ash can be recycled and reused. Metals such as zinc, lead and cadmium can be disposed of for recycling in several places within the industry sector, and the salt has become so pure it can be used as de-icing salt in the winter.
That is to say, the fly ash is not just de-icing salt being cleansed; the residual products can also be recycled. In addition, through the Halosep process, the total amount of ash is reduced by 40%. Right now, at Vestforbrænding, they are testing ways of utilising this clean ash, as well as using the metals and salts. It is therefore expected that a useful purpose will also be found for the pure ash. This ash is very fine-grained and, as a result, it can be incorporated into good constructional material. It could be as fill material in concrete or cement, and it will have yet another environmental benefit, as it can contribute to lowering the fill material’s CO2 emissions of the concrete and cement industry.
Halosep technology has been integrated into the existing framework at Vestforbrænding. It has always been the goal of the Halosep developers to improve the incinerator plant’s existing conditions so that no new buildings are needed. This helps to reduce resource consumption when installing the technology.
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At Vestforbrænding they are highly satisfied with the new plant and the prospect of no longer having to dispose of large quantities of hazardous waste in the form of toxic fly ash. The project is considered as part of the development to constantly make optimum use of the power plant processes:
- We not only have a responsibility to burn waste and supply electricity and heat to people, we also have a responsibility to limit our environmental impact and to optimise the way we use our resources. We constantly strive to make things better by implementing new technology and making the most of operations, claims Samuel Moore at Vestforbrænding.
Stena Recycling sees great potential in extending the Halosep technology further to several waste incineration plants in Denmark and the rest of the world:
- We have high expectations for the distribution of Halosep and we are also experiencing increasing interest from other waste incineration plants. We have just started a similar project in Norway, where fly ash is being processed for recycling instead of landfill, explains Erik Rasmussen, Project Manager at Stena Recycling.
- Uponor is the supplier of all of the 18 tanks used in the Halosep process at Vestforbrænding. They are, among other things, reaction tanks, where many of the purification processes take place, mixing tanks and tanks for storing the purified ash. Since the Halosep process includes several strong chemical compounds, the choice of materials was very limited, states Project Engineer Bent E. Rønfeldt at Uponor Infra, adding that:
- Weholite pipes were the obvious choice, since this PE material withstands most acids and bases. The material is easy to work with and makes it easy to establish connecting pipes and to install equipment. In addition, it has been easy to make adjustments on a continual basis, since you do not depend on special tools or casting moulds. The close cooperation between Stena Recycling, Vestforbrænding and Uponor made the delivery of the tanks an easy ’plug-and-play’ solution.
Bent E. Rønfeldt is pleased that Uponor, as supplier of the Halosep tanks, is contributing to a significant reduction in the amount of hazardous waste from heating and power stations:
- Circular economy, recycling and sustainability are the keywords in Uponor’s mission. Uponor will take part in projects that make a difference to people, society and the environment. For this reason, Uponor is proud to have been a part of the thought process behind this pioneering project, Rønfeldt concludes.
The plant will start up in 2020, and it will then run for one year as a development and demonstration project. After that Halosep will become a standard fixture at Vestforbrænding. Halosep technology possesses great potential in relation to the environment, and the individual waste incineration plants have financial gain in prospect. It simply makes good business sense to cleanse the fly ash and sell the metals. Vestforbrænding expects that chemical savings and the sale of metals will bring in 1.5 million annually. Furthermore, you save money on not having to deposit large amounts of hazardous waste. The investment in Halosep is scheduled to make a return after six to eight years.Building owner: Vestforbrænding
Halosep tecnology: Stena Recycling
Weholite tanke: Uponor Infra A/S