Importance of odor reduction in plant operation
A decisive factor for the acceptance of composting facilities is the question of the odor emanating from the facility. For plant operators, effective odor reduction is not only relevant with regard to residents, but also for their own operations, plant personnel and delivery traffic. Odor reduction measures make a significant contribution to ensuring stable and permit-compliant operation.
Technical principle of odor reduction with ACT
The ACT composting system works with targeted aeration of the rotting material in combination with a semi-permeable membrane cover. The process air, blown in through channels embedded in the floor, flows through the rotting material and rises to the top. The air heats up and absorbs moisture.
Moisture condenses on the inside of the membrane and forms a film of water. This acts as a biologically active retention chamber in which odorous substances are bound and returned to the biological decomposition process in the rotting material. In this way, the release of odorous substances from the rotting body is significantly reduced without impairing the rotting process itself.
Validation of odor reduction with the ACT system
To assess the odor reduction, odor emissions were measured at an existing composting plant in late summer 2025. The measurements were carried out during ongoing plant operation and specifically during intensive rotting, as experience has shown that the highest odor emissions occur during this phase and the effectiveness of reduction measures can therefore be assessed in a particularly meaningful way.
Rotting bodies without cover and rotting bodies with ACT membranes of different age classes were investigated. The aim of the measurements was to determine the actual degree of reduction in odor emissions caused by the membrane cover under real operating conditions.
Sampling and evaluation of odor emissions were carried out in accordance with the recognized rules of technology. The odorant concentrations were determined using dynamic olfactometry in accordance with DIN EN 13725. The emissions at the rotting bodies were recorded using hood measurements in accordance with the relevant guidelines for area sources.
The measurements were carried out by a measuring institute notified in accordance with § 29b BImSchG. The commissioned institute is accredited by the German Accreditation Body (DAkkS) and has the corresponding recognition to carry out odor measurements on systems requiring approval.
Results of the odor measurement
The measurement results were more than convincing. When applied to waste from the organic waste garbage can, odor reductions of up to 98 % were achieved in comparison with the semi-permeable membrane for open composting. Over several measurements, the average reduction rate was 97 %.
The results clearly show that the ACT system enables very high and stable odor reduction even under demanding operating conditions.
Added value for system operators
Effective odor reduction is a key component for smooth system operation. It helps to minimize conflicts with the environment, safeguard operations and reliably meet official requirements. At the same time, it significantly reduces the organizational and communication effort involved in dealing with odour issues.
For plant operators, this means greater operational reliability, greater acceptance and a long-term, reliable solution for reducing emissions.
Individual measurement and demonstration on site
The relevant reports are available to us and can be made available to the relevant authorities if required. If an authority or operator wishes to carry out their own assessment, we can also use our mobile demonstration system to measure the system emissions on site.
This gives you the opportunity to test the effect of the ACT system yourself under your individual site and operating conditions.
Text by Jonas Schmidt and Florian Volk