Treatment process
Ozonation
A powerful oxidant generated on site, used both for disinfection and for breaking down taste, odour and micropollutant compounds.
Key facts
- Scale
- Municipal
- Treatment stage
- Disinfection and oxidation
How it works
Ozone is produced by electrical discharge through dry air or oxygen and dissolved into the water. It decomposes within minutes, so it leaves no residual.
What it removes — and what it does not
| Row | Removes | Does not remove |
|---|---|---|
| 1 | Bacteria, viruses and Cryptosporidium at adequate contact | Dissolved salts, nitrate, hardness |
| 2 | Taste and odour compounds including geosmin | PFAS, which resist oxidation |
| 3 | Colour | Provides no lasting residual |
| 4 | Iron and manganese by oxidation | — |
| 5 | Partially degrades pesticides and pharmaceuticals | — |
Trade-offs
- Forms bromate where bromide is present, which is itself regulated
- Energy intensive
- Usually followed by biological activated carbon to remove the biodegradable compounds it creates
Related intelligence
Reverse osmosissame topicChlorinationsame topicGranular activated carbonsame topicCombined sewer overflowsame topicIon exchange softeningsame topicUltraviolet disinfectionsame topicCoagulation and flocculationsame topicActivated sludgesame topicRapid gravity filtrationsame topicChloraminationsame topicDistillationsame topicSlow sand filtrationsame topic
Sources
- World Health Organization — Guidelines for Drinking-water Quality. Public but restricted · CC BY-NC-SA 3.0 IGO
- NSF International / American National Standards Institute — NSF/ANSI drinking water treatment unit standards. Public but restricted · Publisher terms — public access, reuse not clearly granted
- American Water Works Association — AWWA standards, water audits and utility benchmarking. Public but restricted · Publisher terms — public access, reuse not clearly granted