Pioneering And Courageous: That's Recycling

07 December 2021

As featured in Aggregates Business Europe.

In planning and constructing the Schuppis Excavation and Soil Washing Plant in the Swiss town of Goldach, CDE has implemented a truly pioneering project on behalf of Walo Bertschinger AG Ostschweiz. More than anything else, the decision to create such a plant called for a lot of courage as well as confidence in the future of recycling, and all credit here is due to Matthias Züst.

The Walo Bertschinger AG Ostschweiz plant in the Swiss town of Goldach on the southern shore of Lake Constance is impressive right from the start. Your first glance is drawn to the lettering displayed on the roof cladding of a building of an extremely clean and well- thought-out design. It names the entire site as ‘Walo Aushubund Schotterwaschanlage Schuppis’, which, as well as a covered hall that is open to the front, comprises a paved yard with a range of bulk material bays and a new, cleverly incorporated weighing and office building. Look again and you will see, seemingly towering over the whole site, a cable excavator which looks almost antique but is in a very good state of repair. “The main thing is it still works,” explains a laughing Matthias Züst as he extends us a very warm welcome.

And Matthias Züst should know, because up until the summer of 2018, the site was occupied by a gravel works owned by Gerschwiler AG and run by Matthias himself – “and the cable excavator is actually almost the last reminder of the former gravel extraction operation.” Since 2019, the site, which is on the Thannäcker industrial estate, has belonged to Walo Bertschinger AG, a Swiss-based, internationally active construction company with a wide range of specialities, including road-building, civil and structural engineering, railway construction, ground coverings and sports ground surfaces.

11 years, 11 months and 11 days

“Because I didn’t have any successors for my Gerschwiler AG, the merger with Walo was a logical way of ensuring future prospects for my old business in general and for my employees in particular,” explains a convinced Matthias Züst, whose present role with Walo is ‘Head of Aggregates and Transport’. And ‘prospects’ takes us to the very heart of the issue. Züst has been involved in reorganising the sites in Goldach since 2007, “and you could say that the entire preparation and planning procedure – up to commissioning the new plant – took exactly 11 years, 11 months and 11 days,” according to research by Silvana Jakob, a colleague of Matthias Züst who was charged with implementing the whole project.

In Switzerland as in Germany, raw material extraction is an extremely difficult issue in light of the situation relating to licensing laws. To this we must add that Switzerland is a country lacking in raw materials: “There is now no raw material extraction at all in eastern Switzerland, plus the growing shortage of landfill space makes it increasingly expensive,” says Züst. He goes on to explain that the two municipal landfill sites which are important for Goldach are not always open, and an acceptance price of around 24 francs per cubic metre makes them almost unaffordable, so reducing the amount of excavated material is an urgent necessity. “The foreseeable end of gravel extraction on the current site made us all realise that we would have to reinvent ourselves. No new licences were being issued, and there was also a shortage in the supply of ballast for the Swiss Federal Railways (SBB). Therefore, about four years ago, the idea of washing railway ballast suddenly became very interesting. We tested it in the old gravel works, and it worked. This led to the idea of implementing it systematically in a new facility.”

Systematically planned and implemented

This is exactly where CDE enters the picture. For many years now, the Irish company's experience in wet processing a wide variety of materials has made it very successful in the market. In Matthias Züst, CDE Europe's Sales Manager for the DACH market Christoph Baier, found not only a customer but also a partner who knew exactly what he wanted: “We are concerned solely with gravel excavation and uncontaminated railway ballast for the SBB. We cannot recover any stones from pure humus.”

Following preliminary in-depth discussions, surveys of existing plants and the completion of detailed planning, the construction contract was finally awarded in the summer of 2018. In the summer of 2019, the excavation and soil washing plant was commissioned at the end of a year's build. It is probably one of the biggest plants of its kind in Europe – as the end products 0/2, 0/4, 4/8, 8/16, 16/32, 32/50 for track ballast, as well as 50/80 and the high-grade chippings prove, the effort was absolutely worth it – or to get straight to the point: the quality of all these products is totally compelling.

Every hour, the washing plant, which covers an area of approx. 3500m², scrubs between 120 and 180 tonnes of ballast material which, like the excavated gravel material, is delivered in different grades. Careful, separate storage of the different input materials is therefore essential for achieving the best possible product results with the selective, material-dependent processing of the input. The processing area is enclosed on three sides and has a roof cover so it can operate regardless of weather conditions.

All the individual product lines are oriented lengthways in the hall so as to logistically optimise interim storage in the bulk material bays. A 105-metre long service tunnel runs beneath the shop floor to provide optimum access to the pumps and water supply at any time. The materials are processed using both industrial and fresh water, the latter being used in the final stage so as to achieve products that are as clean as possible. The industrial and fresh water are of course both run in a closed circuit, so the only losses are from the residual moisture adhering to the products.

The main components in the processing system are the different series-connected screening stages, the water and buffer tanks, thickeners, the sludge water treatment facility, a generously dimensioned log washer with its upward flow device and – one might almost say ‘the highlight’ –

The filter press with 194 chambers, each one 2  by 2 metres in size. “It is one of the biggest and therefore the most efficient of its kind,” emphasises Christoph Baier proudly. Depending on the input material, it can deliver around 25 tonnes of filter cake per hour with the aid of the right flocculent. The filter cake is then carefully examined in the laboratory so it can be taken to the approved landfill sites if it has no practical use.

Analysis and documentation are two very essential aspects accompanying the actual processing work, as Matthias Züst explains: “We are constantly having to prove that the washed railway ballast really meets all the requirements, including as regards its compressive strength, for instance. Hence the need for accurate checks and analyses, not least for our own safety!”

Recycling – there must be a pioneer

The processing plant is more than imposing, not just in its size but also in all the details which were so important for Matthias Züst. The plant was designed to operate over many years while offering optimum flexibility. In CDE and in Christoph Baier in particular he “found the right partners” who have always “demonstrated the necessary understanding” of his concerns. He sees ‘recycling and sustainability’ as the decisive elements of a future raw material economy that must rely much more on recycling.

“Our focus on sustainability is also shown by the photovoltaic system on the roof over the processing area. It can cover all of our power needs.”

Recycling is something to which he attaches particular importance. “There is still much to do here before this idea really takes hold. If the canton of St. Gallen runs out of landfill space in two years, then more recycled construction materials will just have to be recovered and used. But even if just the tiniest proportions of tiles or red bricks crop up in our products, then they will not meet the standards, even though they are just as good as primary raw materials. Some things still have to change, including and above all in the minds of buyers, customers and politicians.”

So we need more such plants and more pioneers like Matthias Züst who are willing to take on such challenges with a healthy degree of caution and above all, courage. “I wouldn’t call it ‘fear’ so far as the worry about financial resources was concerned. In fact, the plant is now earning more than we originally planned. But above all, you need courage to build something like that. And courage is what I had, thank goodness!” Let us be glad that Matthias Züst had the courage. This showpiece plant is truly worthy of it.