The world largest sewage treatment plant is Stickney Water Reclamation Plant in Chicago at 4.9 million cubic metres per day. This guide profiles Stickney and its top 10 runners up, showing the mega city sanitation infrastructure that defines urban water quality.
The top 10 and their scale
| Rank | Plant | City | Capacity (m3/day) |
|---|---|---|---|
| 1 | Stickney | Chicago | ~4,900,000 |
| 2 | Deer Island | Boston | ~4,400,000 |
| 3 | Bailonggang | Shanghai | ~2,800,000 |
| 4 | Beckton | London | ~2,800,000 |
| 5 | Achères | Paris | ~1,700,000 |
| 6 | Ochiai | Tokyo | ~1,600,000 |
| 7 | Blue Plains | Washington DC | ~1,400,000 |
| 8 | Newtown Creek | New York | ~1,300,000 |
| 9 | Xiangyang | Guangzhou | ~1,000,000 |
| 10 | Werribee | Melbourne | ~1,000,000 |
Stickney: the world leader
Stickney Water Reclamation Plant covers about 260 hectares south west of Chicago. It receives sewage from over 2.4 million people plus industrial dischargers across the Chicago metropolitan area. Peak wet weather capacity 4.9 million cubic metres per day. Owned and operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC).
History
Stickney was built in 1930 and has been continuously expanded and upgraded. Original design incorporated primary sedimentation and trickling filters; modern operation includes activated sludge secondary and advanced solids handling.
Process
Preliminary screening and grit removal, primary sedimentation in massive tank arrays, activated sludge secondary treatment, and disinfection. Sludge processed through anaerobic digestion producing biogas that powers plant operations. See our companion article on how a sewage plant works.
Deer Island: modern engineering
Deer Island in Boston Harbor treats sewage from 43 municipalities. Iconic egg shaped anaerobic digesters visible from surrounding areas. Commissioned in 1995 as a modern replacement for Boston legacy plants. Operated by Massachusetts Water Resources Authority.
Beckton: London mega
Beckton in East London is the largest sewage plant in Europe by capacity. Recently connected to the Thames Tideway Tunnel for wet weather management. Operated by Thames Water.
Asian mega plants
Bailonggang in Shanghai, Ochiai in Tokyo, and Xiangyang in Guangzhou each treat over 1 million m3 per day. Asian city expansion has driven mega plant scale. Indian and Chinese cities are building similar plants at pace.
Operational scale
Technology consistency
All top 10 use activated sludge secondary treatment with anaerobic digestion for sludge. Advanced treatment for nutrients present at Blue Plains, Beckton, and Werribee. Membrane bioreactor upgrades under study at several sites.
Climate resilience
Coastal plants (Deer Island, Beckton) face sea level rise. Inland plants (Stickney, Blue Plains) face intense rainfall. All have climate resilience programmes underway.
Future changes to the ranking
Chinese and Indian plants will rise. Middle East arid plants may enter with reuse focus. Existing US and European plants continue at similar scale but with upgrades.
Workforce at scale
Each top 10 plant employs several hundred operational staff. Certified operators, mechanics, electricians, laboratory chemists, and engineers. Some plants operate as 24/7 with multi shift rotation.
Public engagement
Many plants offer tours and public education programmes. Deer Island and Beckton have prominent public engagement including museum style exhibits. See our companion article on urban sewage management.
Frequently asked questions
Which is the largest sewage plant?
Stickney in Chicago at 4.9 million m3 per day.
How does Stickney compare to Deer Island?
Stickney is larger by capacity. Deer Island is more modern by design vintage.
Are these plants all activated sludge?
Yes at secondary. Some add advanced treatment.
How many people do they serve?
Millions each. Stickney serves over 2.4 million people plus industrial.
Do they generate biogas?
Yes, most produce biogas from digestion for on site energy.
Are they publicly owned?
Most yes. Some UK plants under regulated private ownership.
Do they treat industrial waste?
Usually yes, with pretreatment requirements for industrial dischargers.
How reliable are they?
Very. Redundant treatment trains and backup power ensure high availability.
Can I tour these plants?
Many yes. Contact the operator.
Where can I read more?
Operator websites, EPA ECHO, and the UtilityRadar directory.
Summary
Stickney near Chicago is the world largest sewage treatment plant at 4.9 million cubic metres per day. Deer Island, Beckton, and Bailonggang follow. The top 10 collectively process the wastewater of roughly 30 million people. All are engineering marvels operating at the scale of small national infrastructure. Future rankings will feature more Asian and Middle Eastern plants as global urbanisation continues.
Next reading
- 15 largest wastewater plants
- How a treatment plant works step by step
- City sewage management
- Browse the wastewater plants directory
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