Vocation and avocation

Hubert Seiringer first heard about compost when he was 15 years old. When he was 20 he founded his own company, and today, 30 years later, composting is still his passion.

May 03, 2016

At the edge of Wieselburg in Austria, a mighty square farm stands on a hill. A closer look reveals that there is a composting plant in addition to farm buildings. But you wouldn’t know it from the smell, or lack thereof. “Every year we turn about 20,000 tonnes of green cuttings and organics into high-quality compost,” says Seiringer, and right away you can tell that the term ‘high quality’ isn’t just something he throws out there. “Compost is about quality. If the quality’s good, sales will not be a problem.” He’s sure of it.

It is Seiringer’s conviction that the right processing and machinery are critical to getting clean compost. “We leave the material in the rotting area for eight to twelve weeks, turning it once or twice a week. Then we screen it to under 12 millimetres and do a ferrous separation. Almost all the plastic ends up in the screen overflow. That’s where the Hurrikan wind sifter comes in. Since we run all of the screen overflow back through the process, cleaning is an absolute necessity. If we didn’t, contaminants would build up in the screen overflow.” If plastic stays in the composting process for a long time, it starts to age, get brittle, and break down into smaller and smaller pieces under mechanical stress like turning. Then not even fine-grain screening will get them out. Seiringer solves the problem with a stationary screener and downstream Hurrikan, which he converted from mobile to stationary, and which will soon complete its 15,000th operating hour. For mobile support there is a Maxx trommel and another Hurrikan for contract jobs.


Another contaminant also used to make screen overflow recycling harder - stones! Plastic’s colour and flatness make it stand out, but stones look much more like the material they come with. Seiringer estimates that his screen overflow is about 10 percent stones by weight. Since he shreds the screen overflow before running it back through as structure material, a lot of stones mean a lot of shredder wear. “Low speed shredders are fairly tough in this respect, but the teeth definitely stay sharp longer without the stones, and shredding is more efficient,” says Seiringer.

The solution was a new Hurrifex separator that can get rid of stones as well as light materials like plastic film. The screen overflow goes through the Maxx to separate out the fines again, and then to the Hurrifex. Seiringer sets it so that it gets out almost all the stones. It also takes care of any plastic film the Hurrikan missed. Naturally Seiringer was involved in the design of the Hurrifex, helping Komptech’s developers with the final details. The output is an absolutely clean screen overflow that shreds problem-free for a new composting run-through.

“We’re almost always sold out” - Seiringer’s products are popular and demand is healthy. Some of this has to do with canny positioning for different customers and needs. But Seiringer stays busy with more than just running his composting operation. He developed an innovative ventilation system to make decomposition go better, and 80 of the systems are in use around the world. Organic farming and forestry are his personal passion, and as chairman of Arge Kompost & Biogas he represents 2/3 of Austrian plant operators. The organization transfers knowledge and looks out for plant operators’ interests, and requires annual Arge quality control certification for all of its members.