The advantage of our activated carbon is its wide range of application regarding the pollutants to be eliminated and its good removal efficiency, even at very low residual concentrations. There are numerous modifications of activated carbon. Thus it is possible to choose the carbon with the best absorption capacity towards the pollutants. Its successful use does not only depend on the technology itself but also on the know how: It must be clarified which process is best for which application. Especially important is the consideration whether the process is economically and ecologically adapted.

Characteristics of the Tholander process in keywords

A big advantage of activated carbon filters is, apart from their almost universal applicability, the simple process involved: It is a filter of custom-made size, in which the waste air slowly travels through the carbon bed. The pollutants to be cleaned finally accumulate on the surface area of the carbon and are oxidised in the fine pore structures. This only works until the carbon is saturated having no further capacity to eliminate the pollutants. A regeneration of the carbon is absolutely required at this stage. As opposed to our water regenerable carbon, the regeneration of standard carbons involves high costs for removal/exchange and high energy consumption. This is why you have to carefully check whether it make sense to use standard carbon or not.

For this reason we have chosen an activated carbon produced in such a way that it can be regenerated in-situ without any additional energy consumption.

Many of our customers have humid or water vapour saturated waste air to be treated. Standard carbon can only be used in a limited way under these conditions. Modified carbon having a high adsorption capacity in the presence of water vapour, is, however, not regenerable: It must be catalytically oxidised after reaching its saturation and having no further capacity to eliminate pollutants. This “throw away concept” is not longer appropriate. We have, therefore, decided for an on site regeneration concept being simple and cost-effective at the same time.

We use impregnated activated carbon (activated carbon pellets with catalytically active K₂C0₃) forming H₂S at the carbon surface to sulphuric acid (H₂SO₄) by means of catalytical oxidation. Once the carbon is saturated, it can be regenerated with water whilst still being in the filter. The carbon filter is therefore filled with good quality water. After a short period, the diluted sulphuric acid solution contained in the water can be discharged to the sewage system.

Whenever this easy to regenerate activated carbon cannot be used, we offer active carbons that in combination with suitable pre-treatment or intelligent air management concepts offer the best possible rentability. As for all of our air treatment units, we will then study for our customers the advantages and disadvantages of the possible technology and work out an optimized concept regarding the costs of investment, operation and maintenance. Our activated carbon adsorbers can be designed for any air flow rate requested.

Using activated carbon filters especially makes sense for air flows

• which have already been pre-treated but which cannot be cleaned cost-effectively with other methods
• having such a low flow rate that the use of other air treatment systems would be too expensive
• that cannot be connected to a central air treatment system
• containing only one or a few different pollutants which can be regained during the regeneration process of the carbon
• that cannot be cleaned sufficiently to the required clean gas value by other methods
• that are not continuously expected
• containing a special exhaust air component to be removed selectively (e.g. H₂S)
• requiring a polishing filter for reasons of safety

Our activated carbon filters are especially used for

• Sewage and waste treatment operations