Odour Control for Wastewater Plants
Odour control systems that treat H₂S and other odorous air from sewage and effluent plants.
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Treatment of odorous air from sewage and effluent plants
CRA's odour control systems remove H₂S, mercaptans, ammonia and VOCs from the air drawn off wastewater plant sources, with chemical, biological and activated carbon stages matched to the load.
Target compounds
H₂S, mercaptans, ammonia, VOCs
Technologies
Chemical, biological, carbon
Sources
Works, tanks and sludge handling
Operation
Continuous duty
How does odour control work at a wastewater plant?
Odorous air is drawn from covered sources such as inlet works, tanks and sludge buildings and sent for treatment. A chemical scrubber washes the air with a circulating solution, a biological unit uses bacteria on packing media to break down the compounds, and an activated carbon stage adsorbs what remains. The treated air is then released.
How it works
The technology, or combination of stages, is chosen from the compounds in the air, the flow and the space and utilities on site.
Foul air is drawn from covered sources across the works.
Stages are chosen for the compounds, the flow and the site.
Chemical or biological treatment removes most of the odorous load.
Activated carbon brings the remaining odour down to low levels.
The treated air is released after the final stage.
Key Benefits
The systems target H₂S, mercaptans, ammonia and VOCs.
Chemical, biological and carbon stages are chosen for the compounds and the flow.
Two or more stages are combined where one cannot meet the outlet target.
The systems run around the clock alongside the treatment process.
Removing H₂S from the air protects staff and reduces corrosion.
The CRA Edge
CRA has more than 30 years of experience in gas handling and flare engineering.
Design, R&D and manufacturing are carried out under one roof.
ISO 9001 certified through TÜV NORD, with designs aligned with ASME, API and CE.
Designs are customised to the process needs and the regulations that apply at site.
Applications
Built to help you specify.
Sizing tools, decision guides, and technical references. Use them before, during, and after your evaluation.
Frequently Asked Questions
What causes odour at a sewage treatment plant?
Most of the odour comes from hydrogen sulphide released where sewage and sludge are agitated or held, such as inlet works, pumping stations and sludge handling. Mercaptans, ammonia and organic compounds add to it.
Which odour control technology suits a wastewater plant?
CRA selects the treatment from the compounds in the air, their levels, the flow and the site: biological treatment, chemical scrubbing and activated carbon polishing, alone or in stages.
Can different technologies be combined?
Yes. Where one technology cannot meet the full requirement, CRA combines stages, for example biological treatment followed by carbon polishing.
What data does CRA need to size wastewater odour control?
CRA needs the air flow from each source, the measured or expected H₂S and other odour compounds, the outlet target and the site conditions.
Does CRA treat digester gas as well as odorous air?
Yes. CRA also supplies H₂S scrubbers for digester gas, which protect engines, boilers and flares.