Aircon BG-filter re-opens source of income for Finnish customer

Aircon BG activated carbon filter

No business will enjoy losing a substantial part of their budget due to a technical problem. A Finnish municipal public enterprise was looking to commercialise landfill gas again. The answer was Desotec activated carbon filtration.


The Finnish city in the Northern Savonia region, is operating a landfill site where they collect all the household waste from the surrounding area. Bacteria contained in the waste produce on-site ‘landfill gas’. This type of biogas is being pumped up for two reasons : first of all to prevent ignition of the waste, and secondly to send the gas through an underground pipeline to a commercial partner who uses the landfill gas for green power generation and heat.


An important condition for this commercial deal was to keep the H2S concentration in the landfill gas below 100 ppm. Some years ago this essential requirement was no longer met as the H2S concentration rose to no less than 1,200 ppm. For a long time the municipal public enterprise did not seem to find an acceptable solution. Various solutions were considered, and then dismissed because the capital expenditure was too high and guarantees in terms of results were oblivious.

After an analysis of the problem we proposed the installation of an AIRCON BG-filter. This is a double-walled vessel, and the insulating layer between both walls significantly reduces the risk of condensation in the activated carbon filter.


Desotec supplied the filter from its operational hub in Gdansk, Poland. The filter, which was filled with impregnated activated carbon, was installed in early January 2019. The AIRCON BG-filter – the slightly smaller brother of the AIRCON HC-XL-filter – can process a flow rate of approx. 550 m³/h of landfill gas and immediately showed very reassuring results: the input concentration of 1,600 mg of H2S (1,200 ppm) was found to be zero at the output : 0 ppm. After analysis of the results, the green power producer immediately decided to resume the deal with the municipal public enterprise. A big sigh of relief for Northern Savonia: this new revenue will enable them to make the major investment in the construction of the underground pipeline between both companies profitable again.

For the municipal public enterprise the installation of this mobile activated carbon filter was a virtually risk-free investment: the rental solution offered them the opportunity to explore the possibilities of this technology which was new to them in a non-committal way.  They could contribute to the generation of green power, and once again benefit from a source of income that had temporarily dried up.


At DESOTEC’s facilities, all used carbon is analysed so the right measures can be taken for handling and removing the saturated carbon out of the mobile filters. All molecules that were adsorbed on the activated carbon at the customers’ site, are desorbed inside DESOTEC’s reactivation furnaces. These contaminants are then fully destroyed, in accordance with National and European legislationby an incineration and neutralisation setup. The entire installation and it's emissions are under continuous on-line monitoring, which guarantees that only harmless water vapour is seen exiting the chimney.