Odor Treatment With Nodora CAT, Nodora AirMist Wet Scrubbing and Ozonetech RENA Pro

When Vansbro’s wastewater treatment plant took the leap from 20th-century operations into modern standards in 2024, the focus was particularly on improving the working environment, energy performance, and reducing odor emissions. The facility handles exhaust air from several key parts of the process—including bioreactors, pump stations, sedimentation basins, and a sludge hall—where hydrogen sulfide (H2S) and volatile organic compounds (VOCs) are commonly present.

Due to the close proximity between supply and exhaust air systems, there was a high risk of odor recirculating back into the facility and spreading to nearby residential and industrial areas. A common characteristic of these pollutants is that they often have an extremely strong and irritating odor even at very low concentrations. As such, an effective air treatment system is required to remove these contaminants before the air is released. This is essential to ensure a healthy and pleasant environment for both onsite personnel and nearby residents.

To meet the high demands of the project, an advanced and integrated air treatment solution was implemented, combining ozonation and regenerative catalytic purification. The system was specifically designed to effectively reduce odorous compounds, with a focus on hydrogen sulfide (H2S) and volatile organic compounds (VOCs), both commonly found in air emissions from wastewater treatment plants.

Ozonation is handled by RENA Pro, a compact and modular system that produces pure ozone from oxygen without generating harmful byproducts such as NOx or nitric acid. The ozone effectively breaks down odor molecules at the molecular level, targeting H2S and other persistent organic pollutants. Following this step, the Nodora CAT unit provides catalytic treatment using a proprietary metal oxide media that further reduces H2S. The porous structure of the media enables high mass transfer, ensuring efficient removal even at low residence times. The media also regenerates continuously upon contact with oxygen, enhancing both efficiency and service life.

To handle emissions from the sludge hall, a dedicated horizontal wet scrubber was installed in a separate scrubber building. This system is specifically designed to remove high concentrations of basic, odor-generating gases from sludge handling. To ensure precise system design, Mellifiq carried out on-site VOC measurements, which formed the basis for the sizing of the integrated AirMist system.