The Metropolitan St. Louis Sewer District (MSD) proposed Lower Meramec River Wastewater Treatment Plant (WWTP) primary goals are 1) Enhancing water quality in the lower Meramec River, 2) Accommodating growth in the area, and 3) Providing efficient operations and maintenance. The plant will ultimately serve as a sub-regional facility to treat the wastewater from the District’s lower Meramec Lagoon service area (encompassing the immediate tributary area in St. Louis County and the Jefferson County community of Arnold), and the Baumgartner Lagoon Service area. The existing lagoons at Baumgartner and Meramec and a small treatment plant at the south end of the Gravois Road bridge over the Meramec River would be closed after startup of the new plant. The first phase of construction will be built partially on the area of the existing No. 1 Lagoon. The estimated construction cost for the tunnel and plant project including construction management services is approximately $206 million, escalated for inflation through the five year construction period.

A collection system will be built to convey the wastewater to the new Lower Meramec River WWTP from the existing Baumgartner Lagoons near Baumgartner and Lemay Ferry Roads. The system will consist of an approximate 4 mile long, deep tunnel gravity sewer that will be bored at a depth of 200 feet through rock. At the plant site the tunnel will discharge into a lift station where large pumps will lift the water up to above the surface to begin the flow through the plant’s treatment process.

The plant will be built on a portion of the District’s property presently serving the Meramec Lagoon. Construction will be in phases, Phase I sized for an average day wastewater flow rate of 15 million gallons per day (mgd). This new plant will allow MSD to eliminate the existing Meramec and Baumgartner Lagoon treatment plants. In the future this new plant will be expanded to eliminate the Fenton and Grand Glaize wastewater treatment plants.

Treatment at the plant will include primary and secondary processes to meet all present regulatory requirements. The treatment process will include fine screening of the water as it flows into the plant circular primary clarifiers and grit removal from the primary sludge. Secondary treatment will be achieved using covered trickling filters and circular clarifiers. Sludge created by these facilities will be dewatered in the Process Building using belt filter presses and then loaded into trucks for transporting to a proper disposal site.

Meramac Lagoon Treatment Plant

After primary and secondary treatment, the treated wastewater (effluent) will flow from the plant by way of two outfall pipelines. The primary outfall will discharge through an underground pipe approximately over a mile and one-half to the west bank of the Mississippi River just upstream from its confluence with the Meramec River. The second smaller outfall will discharge a smaller portion of the total plant effluent (2 mgd) through a disinfection process and into the present Lagoon outfall of the wetland preservation area before reaching the Meramec River. This discharge receives further treatment by way of natural treatment system. The purpose of this small second discharge is to help preserve and enhance the ecology that has developed around the existing Lagoon discharge on the District’s property. In addition, the Wetland Demonstration Project will provide a permanent, public exhibition of the use of created wetlands to polish treatment plant effluent to higher water quality standards. The wetland will attract both permanent and migratory wildlife and thus present an accessible demonstration of the compatibility of the water quality improvement via treatment wetlands and wildlife enhancement.

A major emphasis during the planning and design of the Lower Meramec River plant has been on aesthetics such as noise, odor, and visual consideration due to the close proximity of residential areas and the Rogers Elementary School. To address these considerations, the District incorporated a new approach to the process design and plant layout. That approach requires that all wastewater will be conveyed in buried pipelines instead of the traditional exposed open channels. The exposed open channels would be both unsightly and a source of odors. All equipment will be housed in either the main Process Building or in below-ground pipe galleries. This will allow the containment of noise and odor.

As part of the development of this new plant, MSD will also be developing an Educational and Recreational Facility as an interpretive center for the remaining acreage of the site, which contains several varieties of habitat and many opportunities for hiking trails.

This area contains information on the Lower Meramec River Wastewater Treatment Plant project timeline and construction contract packages.

The plant is being designed by CH2M Hill along with their subconsultants TSI Engineering Inc. , Kennedy Associates Incorporated, ERM Technologies, Inc. , and David Mason & Associates, Incorporated.

Construction management services for the plant will be provided by Sverdrup Civil, Inc. /KWAME Building Group, Inc. along with their subconsultants Reitz & Jens, Inc.

MSD plans on issuing ten separate construction packages for the new plant construction. The packages are:

• Site preparation:
  The site preparation (95066E) construction project includes clearing and grubbing, a construction entrance from Telegraph Road into the site and continuing as a haul road through the site, installation of two trailers to be used by District staff, the CM for the treatment plant and the CM for the lift station and tunnel, and installation of a temporary fence to secure the construction site. The existing site is approximately 203 acres and has an existing three-cell lagoon treatment facility on the eastern half and the western half is federally protected wetlands.
  

• Site Preloading Phase I:
  The Site Preloading Phase I (95066D) construction project includes placement of approximately 850,000 cubic yards of engineered structural fill to elevate the wastewater treatment plant site above the 100-year flood elevation. The site will be used for the treatment plant, a master lift station, the educational center and appurtenances.
  

• Outfall Sewer:
  The Lower Meramec River WWTP Outfall Sewer (95066M) project includes construction of approximately 7,700 linear feet of 78-inch diameter reinforced concrete pipe, including manhole structures and an outfall structure discharging to the Mississippi River. All the facilities are being designed to follow the original Lower Meramec River Facility Plan as per the requirements of the Missouri Department of Natural Resources.
  

• Wetlands Mitigation:
  The Wetlands Mitigation project (95066S) is required by the Corps of Engineers due to the elimination of existing wetlands caused by the construction of the wastewater plant and outfall sewer. MSD must mitigate for the permanent wetland impacts by designing and planting approximately 5. 52 acres of forested wetlands (2. 76 acres impacted at 2:1 ratio); 5. 19 acres of scrub-shrub wetlands (3. 46 acres impacted at 1. 5:1 ration); and 1. 25 acres of emergent wetlands (0. 83 acres impacted at a 1. 5:1 ratio). This mitigation can be done onsite, at an off-site location, or at an approved mitigation bank.
  

• Wastewater Treatment Plant:
  The Wastewater Treatment Plant (95066A) construction project will eliminate the existing Meramec and Baumgartner Lagoon treatment plants. The new plant is sized for an average daily wastewater flow rate of 15 million gallons per day (mgd). Treatment at the plant will include primary and secondary processes to meet the NPDES Permit requirements. The treatment process will include fine screening of the wastewater as it flows into the plant's circular primary clarifiers along with grit removal from the primary sludge. Secondary treatment will be achieved using covered trickling filters and circular secondary clarifiers. Sludge created by these facilities will be dewatered in a multi-level process building using belt filter presses and then loaded into trucks for transporting to a proper disposal site. A single level administration/maintenance building will be used to operate and maintain the plant.
  

• Electrical Supply:
  The Electrical Supply (95066K) construction project will provide power and backup power for the treatment plant and lift station. Two 34. 5 kV sources of power from AmerenUE will provide power to an outdoor enclosure containing two incoming fused switches, with automatic transfer logic. The fused switches will feed two double-ended substations with distribution circuit breakers at 480 volts.
  
  One of the two 34. 5 kV power sources installed under Project 95066A, in conjunction with the WWTP and Tunnel projects, was completed in February 2004.
  

• Site Preloading Phase II:
  The Site Preloading Phase II (95066P) construction project includes placement of approximately 370,000 cubic yards of engineered structural fill for consolidation of subsoils and to raise the site above the 100-year flood elevation. This site will be used for the future expansion of the treatment plant.
  

• Natural Treatment Area:
  The Natural Treatment Area (95066J) construction project is expected to consist of one or more constructed wetlands as well as  selectively planted systems of wetland and upland trees and shrubs. The project is designed to provide a natural treatment system for the 2 mgd wetlands discharge from the treatment facility, while creating a public educational amenity.
  

• Educational/Recreational Facility:
  The Educational/Recreational Facility (95666H) construction project will consist of an approximately 10,000 sf interpretive center (building, parking lot, etc. ), pathways in the wetlands area, and an observation deck for public use for passive recreation (e. g. , bird watching, environmental education). Also there is a potential for tying the facility to other park facilities through trails and bikeways. .
  

• Site Restoration/Landscaping:
  The Site Restoration/Landscaping (95666H) construction project will consist of construction restoration, parking, staging areas, signage and a permanent entrance for the treatment plant facility. Landscaping is planned for the plant entrance road and areas outside the treatment plant area.
  

Total cost estimate for the project construction and 
management is approximately $121 million.

The tunnel and lift station are being designed by Horner and Shifrin, Inc. along with their subconsultants TSI Engineering, Inc. , David Mason & Associates, Incorporated, Fleming Corporation, and ERM Technologies.

Construction management services for the tunnel and lift station will be provided by Shannon and Wilson/Black & Veatch along with their subconsultants ABNA Engineering and TSI Engineering, inc.

MSD also plans to issue four separate construction packages for the proposed tunnel and lift station projects.

Tunnel Boring Machine

• Baumgartner Tunnel:
  The Baumgartner Tunnel (95066B) construction project includes approximately 21,000 linear feet of 96-inch diameter pipe in a rock tunnel approximately 200 feet below the ground surface, three access shaft locations approximately 30 feet in diameter for the tunnel and equipment access, and the construction of five drop shafts approximately 6 to 10 feet in diameter at specific locations to convey sanitary flows to the tunnel.
  

• Lift Station:
  The Lift Station (95066L) construction project includes a circular shaft structure approximately 120 feet in diameter and 200 feet deep with intake header pipes directly feeding six pumps having an ultimate pumping capacity of 202. 5 mgd. A screening structure will be located approximately 100 feet upstream of the lift station. This structure will be approximately 26 feet in diameter, 200 feet deep, and contain two 8 feet wide bar screens. A masonry block building will be provided to enclose the bar screens and bridge crane for weather protection and allow for odor control.
  

• Baumgartner Lagoon Closure:
  The Baumgartner Lagoon Closure (95066N) project includes the work necessary to remove, process, transport and dispose of biosolids from the lagoon cells along with demolition of the lagoon berms in order to close this facility as a wastewater treatment lagoon.
  

• Mattese Creek Trunk Sewer:
  The Mattese Creek Sewer (95066R) project includes construction of approximately 2,200 linear feet of 60-inch diameter reinforced concrete pipe along with a tie-in to a drop shaft on the new Baumgartner Tunnel.

Total cost estimate for the project construction and 
management is approximately $95 million.

CONSTRUCTION CONTRACT SCHEDULES