Freiburghaus AG

Freiburghaus AG is a family-owned company, situated in the canton of Fribourg, Switzerland. Operating since 1994 the company offers a range of services including transport logistics, waste disposal, skip hire, vacuum excavation and biogas/digestor plant cleaning.  

The company is a key contractor to the biogas sector, specialising in tank and digester cleaning at waste water treatment and biogas sites. Biogas digestor tanks require periodic cleaning and emptying due to heavy inert material settling on the bottom of the tank. This sedimentation takes up considerable space in the tank and therefore reduces the production of Biogas. High levels of inert materials are also associated with increased wear and maintenance in the plant.

Challenges with traditional tank cleaning methods

Using traditional methods such as vacuum trucks removes the contents of the biogas tanks through large blowers and transports the material via container to a local landfill or incinerator site for disposal.  

Before investing in the MSU:10 G – CDE’s newest portable screen technology - Freiburghaus would typically decant and pump out the liquid on the upper section of the tank, then vacuum the inert rich sludge from the bottom of the tank. This method meant a high moisture content sludge was often being transported for disposal. Disposal costs in Switzerland are high and therefore fractions with high moisture are a costly disposal. Increasingly the incineration of highly liquid waste fraction is being avoided where possible at the waste incinerators.

Freiburghaus AG is now able to process the entire contents of the digestor tank on site; dewatering oversize, inert material and pumping the liquid back into the wastewater treatment works in a continuous process. This results in two main fractions, a dewatered coarse oversize fraction which is organic rich and is typically destined for incineration and an inert rich fraction which through further processing can go into low grade fill applications or has applications in the cement industry. This results in only the organic rich material being transported to the incineration facility, cutting down on transport costs as less water and material is being transported. 

Critically, disposal costs are also reduced as only oversize organic rich fraction is incinerated and the finer inert fraction is a perfect pre-sorted fraction to be upgraded in a larger processing facility. The MSU:10 G not only improves on site processes but it also has environmental impacts in reducing carbon footprint of material transport as well as the incineration energy requirements - who no longer waste energy incinerating the liquid material from the tanks.  

Freiburghaus AG has recently completed a project in the Swiss capital, Bern, on a 54GW hours biogas plant which meets the needs of around 5000 households. The company is completing cleanouts on two of the large digestor tanks with process sludge from ARA Bern water treatment works and also organic waste from industry required cleaning. Around 360m3 of material from each digestor was processed through CDE’s MSU:10G system. The inert rich fraction only has a small contamination of around 6% organics which can be further processed in Switzerland.