The Zweckverband Abfallwirtschaftszentrum Friesland/Wittmund is a municipal disposal company of the two districts of Friesland and Wittmund, which has existed since 1974 with an interruption of 2 years (during the temporary district reform).

The treatment line for the organic waste composting plant has grown old. For this reason, AWZ Wiefels invested into a new chopping mill and into optimisation of the overall plant.

In addition to the new 3-roll screw-type mill that chops up the oversize grain > 60 mm downstream of the drum screen and manual sorting, a dosage roller specifically developed by Neuenhauser Umwelttechnik to optimise the facility was installed for the existing infeed hopper.

Hans Georg Bohlken (plant manager) describes how the process of organic waste treatment has changed by use of the special dosage roller.

"I was sceptical at first when the technicians from Neuenhauser Umwelttechnik recommended the special dosage roller for the existing infeed hopper to us. Now, I can say that the special dosage roller has a key function in the treatment chain. The downstream drum screen has gained a lot of efficiency, since the material is transferred to the screen drum from the conveyor belt in a very even layer height. Screening out of 0 - 60 mm material has improved a lot as well. For the colleagues in manual sorting, consistent material supply of the > 60 mm oversize grain from the drum has some advantages as well, of course. Contaminations are recognised and sorted out better. This is also why we can make do with the low drive performance in the 3-roll screw-type mill. The material is extremely spread out and loosened up by the dosage roller."

“The new 3-roll screw-type mill has a 55 kW electro-mechanical drive. The old chopper was still operated with a 250 kW electrical motor and hydraulic system. This is, of course, evident in the operating costs, maintenance and service costs," Hans Georg Bohlken continues.

The Neuenhauser 3-roll screw-type mill of type G310-XL works with low noise and wear. It is also built robustly and protected from contamination such as ferrous and non-ferrous metals through safety devices. The two upper rolls (working and free rolls) are screw-shaped. They take up the material and pre-chop it gently. This means that contamination such as plastic bags and sacks are opened and cut up, but not torn into small pieces, which would cause problems in the subsequent process steps in turn. The plasterboard roller placed below this chops up the material to a defined grain size.

The Neuenhauser 3-roll screw-type mill has been a fixed part of the product range at Neuenhauser Umwelttechnik for more than 20 years in the area of treatment of organic waste and processing of plaster-containing wastes.

Result:

We don't need to throw out everything that has proven its worth. Renewal is, however, necessary to secure the tried and tested for the future. (Quote by Roman Herzog, former Federal President)