PROJECT DESCRIPTION
BACKGROUND
Municipal solid waste can be treated through incineration, recycling, composting, or sent to landfill. Landfilling is considered the worst solution as it takes up valuable land space, and it also causes air, water and soil pollution. The share of landfilled waste has decreased to be replaced by incineration and the number of incineration plants around EUis increasing.
Though incineration is preferable to landfilling, it causes environmental problems namely the generation of flue gas waste, such as fly ash which contains chlorides and heavy metals. The fly ash is classified as hazardous waste in the European Waste Catalogue. To remove the pollutant, the polluted gas stream is brought into contact with the scrubbing liquid in a wet scrubber. The contact with water over a large area removes the pollutants. However, in most cases in Denmark and Sweden, the FGW waste fails to meet the EU limit values for leaching (i.e. lead and chloride), and often the FGW from these two countries is sent to landfill. Only in Denmark, approximately 200 000 tonnes of FGW is transported to landfills every year and, in some cases, alkaline treatments are needed to neutralise the acidic waste. Therefore, potential resources in the FGW are not utilised. A rough estimate, from previous small-scale tests, showed that about 465 tonnes of zinc and 4 000 tonnes of salt could be recycled from an state-of-the-art incineration plant.. Moreover, about 45 000 m3 of acidic wastewater, called scrubber liquid, is generated in the incineration plant which is used in the HaloSep process to neutralise the fly ash. Utilizing the scrubber liquid using reduces the need for pH regulating and precipitation chemicals.
OBJECTIVES
The main objective of the LIFE HALOSEP project was to demonstrate how two waste streams from incineration plants, fly ash and scrubber liquid, can be co-treated to reduce the amount of waste going to landfill. The innovative HALOSEP process converts the waste into a salt brine product and a zinc product and significantly reduces the amount of flue gas residues, which improves leaching properties so that the material meets safe limits for reuse.
The new technology closes the material loops for chloride and zinc, and thereby contributes to the development of a circular economy. The main advantages are a shift from 100% disposal of fly ash in dedicated landfills to material recycling with a reduction of disposed amounts by about 40-60%; 30-40% cost savings; and less material landfilled, with decreased need for transportation, less chemicals consumption, and increased material available for recycling. The project aimed to demonstrate how the process can be integrated into existing incineration plants so that it can be replicated throughout the EU waste industry.
The project used the Waste Framework Directive and the Landfill Directive guidelines and thresholds to ensure environmentally responsible use of the materials from the HaloSep process. The project also aimed to be mentioned as emerging technology for treatment of fly ash in the Waste Incineration BREF as it improves the recycling and reuse of metals (e.g. zinc) from fly ash and salt brine and reduces the amount deposited in landfills.
RESULTS
LIFE HALOSEP demonstrated at industrial scale, in the main waste incineration plant in Copenhagen region, how two waste streams from municipal solid waste incineration plants, namely fly ash (13,000 t/y) and scrubber liquid, can be treated to reduce the amount of waste going to landfills by approximately 40-60%.
Specifically, the project team showed that:
- HaloSep technology can be integrated into an existing waste incineration plant.
- HaloSep can be integrated with a waste incineration plant’s existing wastewater treatment system.
- The treated fly ash from HaloSep can be safely disposed of in a local landfill site.
- The metal product from HaloSep can be recycled in a zinc recycling facility.
- The salt used in the process can be recycled as road salt for use during the winter period.
- The HaloSep treated fly ash has future potential to be recycled in concrete formulations as a replacement for cement and/or used as a filler or as a construction material, as it is not anymore labelled as hazardous waste.
The project beneficiaries achieved the classification of treated fly ash as non-hazardous under the CLP Regulation, as European Waste Catalogue (EWC) code 19 02 06. This waste code (‘sludges from physico/chemical treatment other than those mentioned in 19 02 05’) has been used in Denmark for the first time. This code means that not only can the treated fly ash be allocated locally to a non-hazardous waste landfill, it means that it also fulfils the first point of the EU criteria to be considered as an end-of-waste material that can be reintroduced back into society.
In the after-LIFE period, measures have been put in place to ensure that the outcomes of the project are utilised. The aim is to ensure a strategic industrialisation and commercialisation of the HaloSep process. As a direct result of the project, HaloSep AB has been established as a standalone legal entity to oversee the process. The target is to mature the HaloSep technology and to commercialise the process for the global market. Four HaloSep plants are planned to be delivered per year.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).
