HEROS case: closing the loop on Zeelands waste

Michiel Poppink

Stage Gate 11 joins forces with the Zeeland-based companies HEROS Sluiskil and SieTec to close the circular loop of bottom ash. The Delta R technology will be used to separate metal flakes that cannot be distilled from the ash at the moment, and make sure these metal parts can also be re-used with high value and quality.

HEROS case: closing the loop on Zeelands waste

Currently, after careful separation for optimal recycling, the leftovers of household garbage and industrial waste get incinerated. Bottom ash is part of the non-combustible residue of combustion in a furnace or incinerator. At HEROS, a waste company in Zeeland, this bottom ash is processed and separated even further at which the pieces of metal and minerals are filtered out one last time. What’s left is a heap of ash, still full of different type metal that cannot be filtered out of this bottom ash in any possible way. These metals can be recycled and reused, however combining different types of metal is not beneficial for the quality of the material.

Board member Arie de Bode explains: HEROS Sluiskil regains metal from bottom ash and by doing that contributes greatly to the circularity of the waste industry. The company even uses the ash as a high-quality mineral secondary raw material, which can be used in the construction and infrastructure industry, closing the loop.


The company aims to separate the small metal parts from bottom ash even further and optimize this process to regain as much as 100% of metal. Striving to maintain quality of the fossil resources and reuse 100% instead of downcycling and lose valuable material to places it cannot be retrieved from anymore.


The question then arises, how can we further extract metals from this mix of metals and metal oxides that have been sorted and filtered in any possible way.


The province of Zeeland provided a grant for this and brought the company’s HEROS, SieTec and Stage Gate 11 together to research whether SG11’s Delta R technology can be used within the waste stream to further identify the metal and how it could be incorporated in the sorting process.
These steps are important and significant for improving circularity in the waste industry. We calculated that this project should make it possible to bring the recovery of metal parts close 10 100%, at which every 0,1% yield already provides major impact on the amount of metal that is saved from landfill and can be reused with similar value.

Stage Gate 11 provides the Delta R technology, an advances spectroscopy, to develop a sensor that detects and classifies metal flakes with the speed of light and without direct contact. The first step of this project is the prove of concept by means of an offline analysis for HEROS. The three companies, Stage Gate 11, HEROS and SieTec will focus on differentiation, position, sorting, and economic feasibility.


The gained knowledge and developments of this research will be shared within the K&I network KicMPI, de province of Zeeland who grated this subsidy ensures, through this project, impact regarding the circularity of Zeeland.


Read more in PZC article

Related insight

Detecting ilicit trace materialhttps://sg11.nl/insights/detecting-illicit-trace-material/

Michiel Poppink

Want to learn more about this project? Contact Michiel Poppink

+31 (0) 88 250 16 00 / insight@sg11.nl