Wastewater odour control protects health, keeps staff safe, and reduces complaints. Plants deal with hydrogen sulphide (H₂S), mercaptans, ammonia, and amines. Left unchecked, these gases damage equipment, lower air quality, and invite fines. The answer is a clear plan that fits the source, the load, and local conditions.
Liquid vs Vapour Control
You can control odour in the liquid phase or in the vapour phase. Liquid phase control treats the wastewater so odours never form or are neutralized early. Vapour phase control captures foul air from covered assets and treats it before release. Many sites use both for steady results.
Liquid Phase Control
Liquid phase control targets points like force mains, wet wells, headworks, and primary clarifiers.
Common oxidants are hydrogen peroxide, ozone, and chlorine dioxide. Each tackles sulphides and related compounds in different ways. Pick the dose point nearest the source, track redox and H₂S near the feed, and keep lines clean so deposits do not re-seed the problem. Short trials on a jar or pipe loop help set dose and contact time without guesswork.
Vapour Phase Control
Vapour phase control focuses on the air leaving tanks, channels, screens, and sludge areas. Air scrubbing passes the airstream through a packed tower sprayed with water or alkaline liquor so H₂S moves into the liquid and is neutralised; this suits sites where H₂S dominates and flows are predictable. Biofiltration pushes air through a media bed colonised by microbes that convert H₂S and ammonia into harmless products; it fits mixed odours and offers low running cost once stable. Activated carbon adsorbs odour molecules in a compact unit; impregnated grades handle tough sulphur species and cope well with short, sharp peaks.