Partial start-up of large-scale project for ara bern is a success
There are few raw materials that are as important and precious as water. That is why the careful processing of wastewater is also so important for protecting our environment. One of the biggest wastewater purification plants in Switzerland is the ara region bern ag facility. Besides wastewater purification, it also processes biowaste. In addition, it uses the organic components to produce biogas containing methane for the public gas network. This year, a receiving and processing facility for commercial biowaste was added to the ara bern wastewater purification plant. The expansion of the Berne facility is one of Tietjen’s biggest projects to date in the biomass sector.
By July 2019, the first milestones had already been passed. By this time, most of the plant components had been delivered and the customer had completed the shell of the new building. We are proud that, at the end of April 2020, the processing plant could be partially started up.
How the processing plant works
The biowaste, which originates from supermarkets, restaurants and large-scale catering facilities, is delivered by trucks and various waste containers. The receiving area is equipped with a large bunker, and provides adequate space for offloading the vehicles. It also has a fully automated system for emptying, cleaning and storing the containers. From the bunker, the homogenised biowaste is fed into the core of the plant, the Tietjen DRM 800.
Easy separation and processing of foodstuffs and packaging
Before fermentation, it is absolutely essential to separate the biowaste from foreign materials and impurities. The more thoroughly and correctly the sorting is carried out from the start, the more cost-effective the whole process is. In contrast to conventional processing methods, the DRM 800 enables the organic materials to be precisely separated from all foreign materials, such as plastic packaging, right from the start of the process. After this, the crushed and mixed organic mass can be optimally utilised both in terms of energy and materials. The foreign materials are also carefully sorted and collected, and fed into a thermal reclamation system. With minimal costs for energy and wear and tear, the DRM separation mill separates out the foreign materials in a single operation and crushes the organic materials to less than 12 mm. This complies with legal requirements.
As part of this major project, Tietjen installed two large storage tanks with a capacity of 150 m³ each in order to buffer the purely organic material and ensure a constant supply for fermentation. To prevent sediments getting into the fermenter, an additional sedimentation basin was also installed by our project partner. With the help of with a tubular heat exchanger, the organic material reaches the fermenter under optimum conditions. The construction of the pipework and specification of the entire process also formed part of the project.