The Metropolitan Water Reclamation District of Greater Chicago (MWRD) – of which the Terrence J. O’Brien Water Reclamation Plant (WRP) is part of – has made a number of upgrades to its treatment process in recent years. The addition of UV disinfection has been a critical part of these upgrades; it played a key role in improving water quality throughout the Chicago Area Waterway System (CAWS).
The Terrence J. O’Brien WRP (originally called North Side) was built to serve residents in communities north of downtown Chicago. In operation since 1928, it originally treated sewage for a population of 800,000 within a 78-square-mile area, but now both the service area and the population are nearly twice as large. The plant now serves over 1.3 million people in an area of 143 square miles and treats an average of 230 MGD of wastewater.
A Need For Innovation
The need for change was recognized by the MWRD Board of Commissioners in 2011 when new regulations required the facility to add a disinfection process to their wastewater treatment system. With the goal of re-classifying the CAWS to allow primary contact, they set out to research the most economical and optimal disinfection technology for the facility.
After investigating various disinfection approaches and technologies, officials determined that UV was the optimal solution for the plant and application.
A low total cost of ownership and the fact that, with UV, there are no disinfection by- products to worry about were key factors in the decision.
In 2013, the MWRD announced that they had selected the TrojanUVSigna™ for installation at the Terrence J. O’Brien WRP. Municipalities around the world have installed the TrojanUVSigna for several reasons. For the MWRD, those reasons included:
- Lowest number of UV lamps required
- Ease of operation and maintenance
- Low total installed capital cost
System Design Parameters
| Peak Design Flow | 535 MGD (2,025 MLD) |
| UV Transmittance (UVT) | 65% at 254 nm |
| Total Suspended Solids | 15 mg/L |
| Disinfection Requirement |
The First, One of The Largest, And Award-winning
The TrojanUVSigna system at the Terrence J. O’Brien WRP was fully commissioned in January 2016, and has been providing effective, reliable disinfection since.
The plant was the first among the 10 largest wastewater plants in the U.S. to implement UV disinfection and is now one of the largest UV wastewater treatment installations in the world.
In 2017, the UV disinfection project at the plant won the American Council of Engineering Companies (ACEC) Illinois Chapter Honor Award, one of the top prizes bestowed by the chapter each year.
Reaping The Benefits of UV
The TrojanUVSigna installed at the Terrence J. O’Brien WRP utilizes TrojanUV Solo Lamp™ and Driver Technology. This revolutionary technology combines the best features of both low- and medium- pressure lamps, ultimately providing a number of tangible benefits, including reduced power consumption and cost- saving lamp dimming capabilities.
The TrojanUVSigna is also equipped with ActiClean™, a patented chemical and mechanical sleeve cleaning system. This system provides superior, automatic sleeve cleaning without having to remove UV banks from the channel or disrupting disinfection.
Terrence J. O’Brien WRP UV Disinfection Configuration
| UV System Type | TrojanUVSigna |
| Number of Channels | 7 |
| Number of UV Banks | 14 (2 banks per channel) |
| Number of Lamps per Bank | 64 |
| Total Number of Lamps | 896 |