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Screw Extruder provides virtually residue-free separation of bio-waste from packaging

Doppstadt DSP 205 solution to challenges of managing packaged food waste

Doppstadt's DSP 205 processes packaged food waste residues reliably without pre-treatment, and without wrapping or jamming.
Doppstadt's DSP 205 processes packaged food waste residues reliably without pre-treatment, and without wrapping or jamming.

According to Doppstadt, their screw extruder DSP 205 is one of the few machines that succeed in separating bio-waste nearly residue-free from packages – without pre- or after-treatment. Doppstadt showcased their screw extruder DSP 205 and informed about further innovations recently, at the EnergyDecentral trade show, held in Hannover, Germany (15. - 18. November, 2016.)

In most cases, food waste from food preparation or spoiled food from production or from consumer sources is mixed with packaging material and other contaminants. Therefore it can neither be composted nor fermented. The process would reduce the contaminants to small pieces and pollute the end product – the compost or the digestate. On the other hand, the high water content does not allow a cost-effective thermal utilization. The DSP 205 screw extruder is a solution to this problem.

This robust machine receives input materials – biowaste, kitchen waste from private households and expired packaged food from production and supply – according to the "receipt as collected"-principle through a hopper and separates fluid from the solid fraction. Packaging material and contaminants are discharged with the solid substances. The bio-available organic fraction accumulating in the liquid phase is a high-value substrate. After fermentation, the digestate can be applied as a fertilizer without further after-treatment.

"Since 2005 the screw extruder has been part of our product range," explains Doppstadt product manager, Arndt Bachmann. "During the past few years we have developed the machine further: Today it can even process residues reliably without pre-treatment, and without wrapping or jamming. It has got a new feeding hopper, which mixes packaged food and collecting bags and opens them by shear stress without shredding them. In this way, only very few contaminants get into the biogas substrate. Furthermore we replaced the hydraulic drives of the DSP 205 with electric drives, thus reducing the operating costs, which were already low.“