German recycling company makes considerable savings thanks to activated carbon filters.

Odour nuisance is a common problem at waste processing companies. It is essential for them to implement efficient odour elimination measures for a variety of reasons. Therefor, a recycling company in Germany invested in activated carbon filters to partly replace the biofilters already in place in the course of 2017. Owing to the positive results and the significant savings, it is likely that this company will fully switch to activated carbon filters from DESOTEC in due course.

Waste disposal is no longer limited to dumping and/or incineration, like it used to be.

Waste is now mainly regarded as a useful, recyclable raw material. Between actual collection and final processing there are different phases in which the waste is temporarily waiting for the next treatment step at storage and transshipment points. Natural odours, the degradability of certain substances and the presence of inorganic components such as sulphur and nitrogen can result in the release of organic odour components and the formation of hydrogen sulphide (H2S) and ammonia (NH3).

Biofilters

In office environments, a good ventilation system is often sufficient to remove the source(s) of unpleasant odours. In production environments, odour issues were until recently solved with the aid of biofilters. These, however, require stable conditions and concentrations to be able to function optimally. This often means that pre-heating and humidification of the air is required, with higher operating costs as a consequence. With an unstable load and varying concentrations, the working bacteria die off and, over time, even start to produce their own unpleasant odours.

Activated carbon filters from DESOTEC can eliminate these inconveniences. First of all, and thanks to their vertical structure, they allow a large filtration surface to be created in a limited space, as a result of which much less square metres are required for the treatment than with biofilters. Also there is no pre-conditioning of the air required, since activated carbon can easily handle variable concentrations.

30% less energy consumption

A recycling company in Berlin produces alternative fuels from collected household waste, which are then, amongs others, used in the cement industry. Under ISO 14001-certification this company decided to replace one third of its existing biofilters with activated carbon filters for effective odour removal in 2017.

From the first results it appeared that this customer could save some 30 per cent on energy consumption, while also considerably reducing operating costs (maintenance of the biofilters). The activated carbon filters (3 AIRCON V-XLs from DESOTEC) each treat 50,000 m³/h and reduce the number of odour units per m³ from approx. 10,000 to less than 250 OUE/m³. Due to the uncertain composition of the household waste, CO sensors monitor the activated carbon filters so an inertization process can take place if necessary. Thanks to the positive results, this company is also considering replacing all bio-filters with activated carbon filters in due course.

 

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.