Sewer Utility Overview

 History of Sewer Utility

The first sanitary sewer system construction began in the early 1900’s in the Flat Branch headwater area, a tributary of Hinkson Creek. Prior to 1950, the sewer system included areas in County House Branch of Hinkson Creek. Around 1960, sewers were extended north along Hinkson Creek and sewers were constructed in the drainage areas of Bear Creek and tributaries of Perche Creek. During the 1970’s and 1980’s, numerous trunk sewers were constructed, including major lines that parallel the Hinkson, Bear and Perche Creeks and delivered to the Columbia Regional Wastewater Treatment Plant, constructed from 1980 to 1982. Sewer extension and trunk sewer construction has continued and the City’s collection system now extends beyond the city limits, consisting of approximately 714 miles of sewer main lines and 16,000 manholes.

Columbia Regional Wastewater Treatment Plant

Please note that the Wastewater Treatment Plant (WWTP) is not the same as the Water Treatment Plant (WTP). The WTP, operated by the Water Utility, is responsible for drinking (potable) water pumped from the alluvial wells in McBaine then treated and distributed to homes and businesses.

The WWTP, operated by the Sewer Utility, intakes sewer water, treats the water, then discharges the clean effluent into the Eagle Bluffs Wetlands. 

WWTP Offices

Construction of the Columbia Regional Wastewater Treatment Plant was completed in 1983 and required approximately 200 man-years of effort in moving 600,000 cubic yards of earth and rock  (enough to fill Faurot Field to the top of the bleachers), placing 75,000 tons of concrete, installing 40,000 lineal feet of piping with 234 valves, and providing $3 million worth of equipment. The total construction cost for the Columbia Regional WWTP was $21 million. An additional $30 million was spent for construction of new interceptor sewer lines to convey waste water to the new treatment plant. The original plant design capacity was 13 million gallons per day. More than 75 small waste water treatment facilities throughout Columbia were eliminated by construction of this plant.

By 1990, in order to meet the needs of a growing community and to continue the City’s efforts to protect streams and groundwater in the area by extending sewers into new developments, it was necessary to increase treatment capacity. In preparation for growth during the next 20 years, the City upgraded the Wastewater Treatment Plant and constructed a series of wetland treatment units (ponds). The fourth treatment unit was completed in 2001. The design capacity of the Wastewater Treatment Plant is approximately 20 million gallons per day.

Additional upgrades to the plant were completed in 2014.

The constructed wetland treatment units are located in the McBaine Bottoms and receive wastewater after it is treated at the original treatment plant. After additional treatment as it flows through the constructed wetlands, the wastewater is discharged to the Missouri Department of Conservation’s Eagle Bluffs Conservation Area on the Missouri River.  

Treatment Plant/Field Operations & Maintenance (O&M)

The Columbia Regional Wastewater Treatment Plant operates on a three shift, 24-hour per day basis year round and is divided into sections:  Field Operations, Plant Operations,  Plant Maintenance, and the Laboratory.  

  • Field Operations is responsible for the operation of the Wetlands and the effluent pumping station located adjacent to the MDC Eagle Bluffs Wildlife Area and the wastewater treatment and spray irrigation system at the Columbia Regional Airport.
  • Plant Operations is responsible for adequate treatment of wastewater and wastewater biosolids (sludge).  A Sludge Pretreatment and Management Program is responsible for the ultimate disposal of the anaerobically digested biosolids by land application, and for annual reporting to MDNR, as well as grounds maintenance at the Regional WWTP, wetlands, and field facilities.  
  • Plant Maintenance performs breakdown and preventive maintenance on plant equipment and all field facilities, makes modifications and new installations as needed, and is responsible for care of buildings.  It also provides routine operation of 11 wastewater pumping stations in the Columbia area.
  • Laboratory performs process control testing, MDNR monitoring and compliance reporting for the Regional WWTP and field sampling for the Sludge Pretreatment Management Programs.  It also serves as liaison with research organizations and provides tours of the wetlands.

How do treatment plants protect our water?

On the average, each person in the U.S. contributes 50-100 gallons of wastewater every day.  If you include industrial and commercial water uses, the per person usage of water is as high as 150 gallons per day.

Wastewater treatment plants:

  • Remove solids— everything from rags and plastics to sand and smaller particles found in wastewater
  • Reduce organic matter and pollutants— naturally occurring helpful bacteria and other microorganisms consume organic matter in wastewater and are then separated from the water
  • Restore oxygen— the treatment process ensures that the water put back into our rivers or lakes has enough oxygen to support life.

Learn more about Columbia’s wastewater treatment process


How does our wastewater treatment plant work?

The 16 million gallons per day (average) entering the facility is conveyed by over 714 miles of interceptor sewers, varying in size from 8 inches to 72 inches in diameter, which are maintained by the line maintenance crews.

The type of wastewater treatment used in the Columbia Regional Wastewater Treatment Plant is called the complete-mix activated sludge process.  This is a biological process in which naturally occurring living microorganisms (bacteria, protozoa, tiny plants and animals) are maintained at a very high population level.  They quickly consume the dissolved and suspended organic material carried over from the primary treatment of the incoming wastewater as a source of food.  This process promotes the formation of biological masses that clump together by adhesion and settle to the bottom forming “sludge.”  

Odors are an inevitable side effect when handling wastewater.   See what is being done.