Lower Meramec Wastewater Treatment Facility Expansion Phase II (12255)


MSD Project Clear is improving its efforts to protect both public and environmental health with a planned construction project located at 7849 Fine Road. The construction site exists on MSD property and will consist of expanding and improving the Lower Meramec Wastewater Treatment Facility with an overall investment of over $117 million. These changes represent an ongoing effort and commitment by MSD Project Clear to improve water quality in the Meramec River. Eliminating the Fenton Wastewater Treatment Facility and improving treatment capabilities at the Lower Meramec Wastewater Treatment Facility will make a demonstrable difference in our region’s water quality.

Public Meeting - February 17, 2022

A meeting customized for residents and stakeholders near the project location took place on February 17 from 6:00 – 7:00 p.m. Viewers can find a recording of that meeting below and download the presentation slides here.

Take a Virtual Tour of the Existing Facility:

The Lower Meramec Wastewater Treatment Facility, with the use of current technology, comes to life on your computer screen with this interactive virtual experience.

Facility Improvements

What work has been done?

  • MSD Project Clear’s engineering and design consultant, HDR, completed the Phase II design to upgrade and update the Lower Meramec Wastewater Treatment Facility. Changes include expanding the facility’s ability to treat additional wastewater flow to allow the Fenton facility to close in accordance with the long-term plan approved by the Missouri Department of Natural Resources. The Grand Glaize Wastewater Treatment Facility was updated, continues to provide excellent treatment, and became a permanent fixture in the MSD Project Clear wastewater system.
  • A separate construction project is currently underway extending the Lower Meramec Tunnel from its current upstream end near Meramec Bottoms Road and I-55 up to MSD’s Fenton Wastewater Treatment Facility. That project is scheduled for completion in 2025.

What work will be done?

  • Changes include the addition of two primary clarifiers, odor control features, a blower building, two aeration basins, three secondary clarifiers, and two disinfection basins. Changes will also see the demolition of the existing, taller, trickling filter structures and secondary clarifiers.
  • On its busiest days – which are also the wettest in terms of precipitation – the current peak flow through the Lower Meramec Wastewater Treatment Facility is 60 million gallons per day. The Phase II project will increase that capacity to 100 million gallons per day.
  • As with past projects at the site, construction crews will access the site from Telegraph Road and not Fine Road (unless Meramec flooding makes the construction access road impassable).

What is the timeline?

This is the current tentative project schedule. This is subject to change based on a variety of factors including weather.

  • Project design completion: December 2021
  • Estimated contractor selection: March 2022
  • Estimated construction start: June 2022
  • Estimated construction completion: Spring 2025

How can I submit questions?

  • This link will open an email to speak directly to the project manager.


The beauty of the area around this facility directly contributes to why this location is ideal for a wastewater treatment facility. The low elevation, the convergence of two rivers, and gravity all work together with the engineering of this facility to create the cleanest water possible from the inflow of our region’s wastewater.

During construction you will notice many changes at the facility. While there will be a significant amount of work going on inside the existing buildings, there will also be new treatment structures constructed in the grassy areas inside the fence line. Once the new structures are in place the taller, existing trickling filter structures will be demolished.

There already are odors on certain days, and yes this will remain true following construction. However, the project includes new odor control systems and overall odors are not anticipated to exceed what you may notice from time to time now.

Construction traffic will not use Fine Road but will enter the grounds from an access road. Only if that access road is unsuitable for driving will the contractors use Fine Road.

There will be typical construction noise on and off during the project.  Some of the new structures require piles for structural support so that will generate noise fairly early in the project. Construction hours will be limited to daytime hours or per St. Louis County permit.

The plans to expand the Lower Meramec Wastewater Treatment Facility will all take place on property currently owned by MSD and on the same property as the existing facility. The footprint of the physical structures will increase during this phase of the project and future phases are an option should regulations require more advanced treatment.

Built as a temporary solution, the Fenton plant has been online for far more years than anticipated. Its location in an active flood zone has resulted in power loss and impacted the ability of our engineering solutions to clean the wastewater on site. Elimination of the Fenton Wastewater Treatment Facility is part of the State’s regional plan for the Lower Meramec watershed, and it has been the plan to expand the Lower Meramec facility to allow this to happen. Treated water from the Lower Meramec facility is actually discharged to the nearby Mississippi River, so elimination of the Fenton facility shifts that discharge from the smaller Meramec River to the larger Mississippi River, improving the overall water quality in our region.

As is true with most things, until someone or something is impacted, change largely goes unnoticed. As a steward of the wastewater and stormwater infrastructure in St. Louis, MSD Project Clear has been planning and designing improved solutions since the district was formed in 1954. Most recently the Long-Term Control Plan specifically created solutions to handle major wet weather events and protect public health. Expecting to be fully online with the new facility in 2025, upwards of 100 million gallons of wastewater per day can be efficiently handled at this location.

FAQs section will be updated as questions are sent in to the Project Manager.

Stay Informed

(Please mention the Project Number: 12255)

Doug Hickey, HDR Engineering, Inc.

Jerry Jung, MSD Project Manager