Odour control scrubbers
Odour is a nuisance in law long before it is a hazard in concentration. Detection thresholds for reduced sulphur compounds sit in the low parts per billion, so an odour system is judged on the last fraction of a percent of removal — which is a different design problem from bulk gas cleaning.
- H₂S
- Mercaptans
- NH₃
- Amines
- Organic sulphides
- Fatty acids
The principle
Most odour duties are mixed: an acidic fraction such as hydrogen sulphide and mercaptans alongside an alkaline fraction such as ammonia and amines. No single liquor chemistry deals with both, which is why serious odour control is usually staged.
A typical arrangement is an acid stage to strip ammonia and amines, followed by an alkaline oxidant stage — sodium hydroxide with sodium hypochlorite — for the sulphur compounds, with activated carbon polishing where the boundary is sensitive.
Staged for mixed odours
Independent liquor circuits per stage, so the acid and alkaline chemistries are held separately and neither neutralises the other.
ORP and pH control
Oxidant is dosed on redox potential and alkali on pH, so the system holds its duty as the load varies through the day.
Carbon polishing where it counts
A final activated carbon bed catches the residual trace compounds that drive complaints near a sensitive boundary.
Designed to run unattended
Reagent level, dosing pump status and low-flow trips are alarmed and reported, because odour plant is rarely somewhere anyone visits daily.
Design envelope
Indicative ranges for this system type. Your figures are calculated against your duty and issued on a datasheet before anything is built.
| Duty range | 500 – 40,000 m³/h |
|---|---|
| Arrangement | Single, two or three stage; carbon polishing optional |
| Stage 1 chemistry | Dilute sulphuric acid for ammonia and amines |
| Stage 2 chemistry | Sodium hydroxide with sodium hypochlorite for sulphur compounds |
| H₂S removal | 99%+ achievable across a staged system |
| Body materials | GRP or polypropylene; PVDF for hypochlorite-wetted parts |
| Control loops | pH and ORP per stage, with independent dosing |
| Bunding | Integral or separate chemical bunds to 110% of the largest vessel |
What it is built to
Equipment is one part of a duty holder's obligations. These are the standards and regulations we design this system type against — your own risk assessment and permit conditions still govern.
- Designed against the site’s odour management plan and permit conditions
- Chemical storage and bunding to CIRIA C736 principles
- Hypochlorite and acid systems kept segregated, with separate fill points and labelling
- UKCA marked; supplied with COSHH data for every reagent in the system
Other systems
Compact fume cupboard scrubbers
Packed-bed scrubbers sized for one to four fume cupboards, built to fit the plant room you already have.
SpecificationsPacked tower scrubbers
The workhorse for soluble gases — counter-current or cross-flow, from a few hundred to tens of thousands of cubic metres an hour.
SpecificationsVenturi scrubbers
High-energy scrubbing for particulate, fume and sub-micron mists that a packed bed will not hold.
SpecificationsTell us the duty and we will size it
Send the gas composition, the flow and the discharge condition you have to meet. We will come back with what will work and what it will take out — and say so plainly if this is the wrong system for the job.