Northwest Treatment Plant

Aerial Photo-NWTP
The Northwest Wastewater Treatment Plant cleans approximately 5 million gallons of wastewater each day for the residents and businesses on the north side of Springfield and for the communities of Willard and Strafford. The plant protects the public's health by eliminating pathogens and water borne diseases and protects the environment by removing organics and nutrients from the water before it is discharged into the Little Sac River.


Safety is a top priority at the NWTP. During the 2007 upgrade, the plant stopped using Chorine gas to disinfect the effluent and started using state of the art UV Disinfection. This eliminated the possibility of a chlorine gas leak. The plant provides safety training each week and encourages behavioral based safety among the staff.

Plant Awards

The Northwest Treatment Plant has been awarded the following National Association of Clean Water Agencies (NACWA) Peak Performance Awards:

                         NACWA - Platinum performance award 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022

                         NACWA - Gold performance award 2008, 2010, 2011, 2012, 2013

                         NACWA - Silver performance award 2007, 2009, 2011


Rotary Drum Thickener 2014

Waste Activated Sludge (WAS) is hauled to the SWTP for further processing into Biosolids. Before 2014, a gravity thickener was used to thicken the WAS before hauling. The process was only able to thicken the WAS to an average of 3% solids. In 2014, Rotary Drum Thickeners were installed to replace the gravity thickening process. The WAS is now thickened to 5-7% solids drastically reducing the number of loads hauled to the SWTP and reducing the overall cost of WAS thickening.

Phase 3, Completed 2009

Carollo Engineers were hired to design the expansion of the Northwest Treatment Plant to meet expected growth of Springfield's north side. Completion of the plant expansion provided the following:

  • The plant capacity was increased to a maximum monthly daily peak average of 9.5 million gallons per day basis which is about a 50 percent increase.
  • Much of the plant including blowers, pumps and valves were automated to provide better process control, while saving energy.
  • New Influent pumping and grit removal allows for future expansion and more reliable treatment
  • Provision for phosphorus and nitrogen removal through the Installation of equipment and tanks. The design of the tanks allows for future expansion.
  • Replacement of aeration blowers, modification of aeration tanks and installation of monitoring and control equipment provided the ability to optimize treatment and reduce energy costs. Aeration tank dissolved oxygen level set points are maintained automatically by in-tank dissolved oxygen probes that control air flow.
  • Addition of a secondary settling clarifier provided better wet weather flow treatment and backup for increased reliability.
  • Hazardous chlorine and sulfur dioxide gases were replaced with ultraviolet lights for disinfection of flow before discharge.
  • All of these improvements were made to provide the best water quality in the State of Missouri for now and in the future. The expansion was designed to provide a safe and environmentally friendly environment while keeping operating cost at a minimum.

Operation Goals

  • Plant personnel, in conjunction with personnel from other sections of the Clean Water Services Division, have adopted and are applying a total team approach toward improving the operation and maintenance of the Northwest Treatment Plant.
  • The goal of the team is to continuously identify areas in which safety, quality and cost savings can be improved within the plant and the division. Once identified, personnel explore these areas to determine the feasibility of making the changes that provide the most positive impact to the plant.
  • The plant has been working to optimize the Enhanced Biological Nutrient Removal process since the 2007 plant upgrade. Recent operational changes have resulted in significantly improved Nitrogen and Phosphorus removal, well below the national average of most wastewater plants.