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Reference project

Rebuilt biogas plant with zero disturbing odor emissions

Air treatment .
H2S and odor removal
Air disinfection
Biogas plants
Air flow
13 000 m3/h


The combination of ozonation and selective adsorption removes all gas pollutants

Our client in this case is a bioenergy company founded in 2016. They are active in a large, Finnish industrial area—one of Finland’s most important food production areas.

The company produces biogas and biodiesel from a combined plant; these products are then used for the treatment of organic residues from the food industry. Their key industrial stages are a continuous dry anaerobic digestion process and a supercritical esterification process. The treatment capacity is about 20 000 tons per year of residues, producing 200 m3/h of raw biogas.

The problem.

Since the company was founded recently, parts of the industrial site required significant rebuilding to be adapted to the new process requirements. H2S is a gaseous pollutant always present in biogas plants, either in the air of the ventilation system or in the biogas after the anaerobic digestion stage. The company decided to adopt a proactive approach, installing a treatment system for preventing any H2S and odor emissions.

The solution.

Mellifiq was commissioned to design and install the whole treatment stage. We chose our most advanced Ozonetech system for air treatment—the RENA Pro B-series—combined with the Nodora ADS active filter, for a final air polishing.

The B-series is perfect when air treatment needs range from moderate to high; the air flow range is normally between 3,000-5,000 Nm3/h. Its design also allows for potential performance upgrades in three stages.

The Nodora ADS systems specialize in adsorbing substances and pollutants such as mercaptans, VOCs (Volatile Organic Compounds), and amines.

The Ozonetech and Nodora systems are designed to work in synergy, maximizing the range of pollutant removal. In addition, the Nodora filter ensures low pressure drops, a very important feature when designing ventilation systems.

Solution facts.
Dimensions (HxWxD)
2,070 x 760 x 1,160 mm and 1800 x 600 x 800 mm
Input power
1.7 kW
Noise level
55 dB


Once more, our combined system proved to keep up with the expectations. Immediately after injection, ozone started to decompose the pollutants due to its fast reactivity. Thanks to the combination with Nodora, the final H2S removal had an average value of 95%, ensuring no odor problems for the surroundings. Due to expected changes in the process conditions, mild variations (± 2 %) of H2S removal were observed, confirming the effectivity of our system even in the most problematic situation.