09/10/2026
💧 ERTC FEATURED PLANTS
Springfield's Wastewater System
Two Plants. One Mission.
When most people think about wastewater treatment, they probably picture a single plant serving an entire community.
Springfield, Illinois, tells a different story.
The Sangamon County Water Reclamation District (SCWRD) operates two wastewater treatment facilities—Spring Creek and Sugar Creek—that work together to serve more than 150,000 people throughout the Springfield metropolitan area and surrounding communities.
Two plants.
Two locations.
Different histories and treatment configurations.
But one mission:
Protect public health, protect our waterways, and provide reliable wastewater treatment for the community.
From a Sanitation Problem to a Regional Wastewater System
The story begins nearly a century ago.
SCWRD was formed in 1924, when Springfield faced a serious sanitation problem. Raw sewage was flowing into area ditches, creeks and rivers, creating unpleasant conditions and putting the community's drinking-water supply at risk.
A bond referendum provided funding for a collection system and treatment plant, construction began in 1925, and the Spring Creek plant began operating in 1928.
As Springfield and the surrounding communities grew, so did the wastewater system.
By the early 1970s, Spring Creek was reaching its capacity.
The solution was another treatment facility.
Sugar Creek came online in 1973.
What began as one wastewater treatment plant serving a growing community had evolved into a two-plant system.
🟦 Spring Creek Wastewater Treatment Plant
3000 N. 8th Street
Spring Creek is the larger of the two facilities.
Today, the plant has an average design flow of approximately 32 million gallons per day (MGD) and a rated peak capacity of approximately 80 MGD.
But the modern Spring Creek facility looks very different from the plant that began operating in 1928.
The facility underwent a major modernization/replacement project that brought new treatment technology and extensive process automation to the site.
Vertical Loop Reactors
One of the most interesting features for an operator audience is Spring Creek's use of Vertical Loop Reactor (VLR) technology.
The plant's biological treatment process provides an environment for biological treatment and nutrient removal, while online instrumentation monitors important process parameters such as dissolved oxygen, pH and oxidation-reduction potential.
For operators, that's an important illustration of how wastewater treatment has evolved.
Instead of relying primarily on periodic manual sampling and adjustments, modern treatment plants can continuously collect process information and use that information to help operators control the process.
SCADA: From Monitoring to Process Control
Spring Creek is also an excellent example of the growing role of SCADA and automation in wastewater operations.
The facility's SCADA system monitors thousands of data points and integrates information from plant equipment, lift stations and control systems. The system provides operators with process information, alarms and control capabilities.
That doesn't eliminate the operator.
It makes the operator's understanding of the process even more important.
An operator still has to recognize when something doesn't look right, understand what the instruments are telling them, distinguish between a process problem and an instrumentation problem, and make the appropriate operational decision.
That's a lesson worth emphasizing to anyone entering the wastewater profession:
Automation doesn't replace the operator. It gives the operator better information to make decisions.
UV Disinfection and Solids Processing
Spring Creek also incorporates UV disinfection and significant solids-processing capabilities.
The facility's solids handling includes dewatering and other processes associated with managing biosolids generated during treatment.
That means the operator's job doesn't end when the liquid stream reaches the end of the treatment process.
The plant must manage everything removed from the wastewater—including solids.
And that's one of the things that makes wastewater treatment such a fascinating profession.
🟩 Sugar Creek Wastewater Treatment Plant
3300 Mechanicsburg Road
Sugar Creek has a different history.
The facility was brought online in 1973 to accommodate the area's continued growth and the increasing demands being placed on the Spring Creek system.
Today, Sugar Creek has an average design flow of approximately 15 MGD and a peak capacity of approximately 37.5 MGD.
But those numbers represent a significant change from the original facility.
🔧 A Major Modernization
In 2017, Sugar Creek underwent a major upgrade that increased its average capacity from approximately 10 MGD to 15 MGD and its peak capacity from 25 MGD to 37.5 MGD. The project also incorporated biological nutrient removal capabilities and highly automated process controls.
The modernization was about more than simply making the plant bigger.
It was about making the facility more flexible, more automated and better prepared for changing treatment requirements.
That included improvements to flow control, screening, grit removal and activated-sludge treatment, as well as processes designed to address phosphorus requirements.
🧱 The Biosolids Story
One of the most interesting aspects of Sugar Creek's modernization is what happens after the biological treatment process.
The facility added two fully automated screw presses for sludge dewatering along with a Class B alkaline stabilization system.
And there's an important operator lesson behind the decision to install two presses.
Redundancy.
The plant could have relied on a single press.
Instead, two units provide backup capability if one unit—or associated feed equipment—goes down. The project team also considered maintenance, cleaning, wear components and ease of repair when selecting the equipment.
That's a very familiar concept to anyone who has spent time around critical infrastructure:
If a piece of equipment is critical to your process, what happens when it fails?
Good plant design doesn't just ask, “Will it work?”
It asks:
“What happens when it doesn't?”
Automation Doesn't End at the Treatment Tank
Sugar Creek's screw-press system is another example of modern automation.
Sludge is fed to the presses, polymer is added, and the equipment controls much of the dewatering process automatically. The system can produce a much drier biosolids product, reducing the volume that must ultimately be handled.
The facility also has to manage the filtrate produced during dewatering because it can contain significant concentrations of ammonia and phosphorus. The return of that sidestream to the plant therefore has to be controlled.
For an operator, that is a great reminder that:
Every process change creates another process to manage.
📊 Two Plants. One System.
Put the two facilities together and Springfield has a substantial wastewater treatment system:
Together, those published design figures represent approximately:
47 MGD combined average design flow
117.5 MGD combined peak capacity
And the two plants serve a regional population of more than 150,000 people.
🌎 Why Two Plants?
There is an important lesson here for anyone who works in water and wastewater.
A community's infrastructure doesn't appear overnight.
It grows with the community.
Springfield started with one treatment facility in 1928.
Then population growth created the need for another plant.
Decades later, both facilities required major modernization to address capacity, regulations, technology and changing operational needs.
That's infrastructure evolution.
And it is happening in communities all across Illinois.
👷 The People Behind the Plants
Of course, none of this happens automatically.
Behind every pump, blower, clarifier, reactor, instrument and SCADA screen are operators and maintenance professionals.
They are the people who make sure the equipment works.
They watch the process.
They collect samples.
They troubleshoot problems.
They respond to alarms.
They make adjustments.
They maintain compliance.
And when something goes wrong at 2:00 in the morning, they're the ones who get the call.
That's why wastewater treatment is much more than a collection of tanks and equipment.
It's a profession.
And Springfield's two-plant system is a great example of how much knowledge, technology and responsibility goes into protecting a community's water resources.
💧 Two Plants. One Mission.
The story of Springfield's wastewater system is ultimately a story of adaptation.
From the original Spring Creek plant of 1928...
to the addition of Sugar Creek in 1973...
to major modernization projects in both facilities...
to today's increasingly automated treatment processes...
the system has continued to evolve with the community it serves.
And that's exactly what the water and wastewater industry must continue to do.
The challenges change.
The technology changes.
The regulations change.
But the mission doesn't.
Protect public health.
Protect our waterways.
Serve our communities.
Two plants.
One mission.
And a workforce that keeps it moving forward.
💧 ERTC Featured Plants
Environmental Resources Training Center at SIUE
Training the water professionals who keep our communities safe, healthy, and moving forward.
siue.edu/ertc
