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Water and Wastewater Plant Directory
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St. Louis, Missouri, USA
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Lower Meramec River Wastewater Treatment Plant
c/o Metropolitan St. Louis Sewer District
2350 Market Street
St. Louis, Missouri, 63103-2555
USA
Contact Information:
Contact:
Email:
CustomerSvc@stlmsd.com
Telephone: 314-768-6260
Fax:
Plant Operation: Municipal
Processing: Wastewater
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Web site:
http://mkasmtp1.stlmsd.com/MSD/PgmsProjs/Projects:MeramecTreatmentPlant
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Plant/Process Description:
The Lower Meramec River WWTP is designed to
treat the plant influent quantity of flows and
water quality in order to meet the effluent
water characteristics established and required
by law. The process was developed to address the
governmental requirements of discharge
standards; the projected influent flow to the
plant and variable loadings that will occur; the
special issues (noise, odor, visual aesthetics);
and MSD’s extensive experience in operating and
maintaining the other existing treatment
facilities in the St. Louis metropolitan area.
The first step is PRELIMINARY TREATMENT
Preliminary treatment includes influent
screening and grit (sand, small rocks, etc.)
removal. Self-cleaning fine screens are
installed as the wastewater flows into the
plant. Solids (screenings) from this process are
discharged into a washer/compactor and are
washed and pressed before discharge to a
conveyor and into a hopper. From the hopper the
screenings are dropped into a truck and hauled
to a landfill or other disposal location.
Grit will be removed by settlement in the
Primary Clarifiers. The grit is then separated
from the sludge allowing more consistent and
higher efficiencies of the process. The sludge
is thickened in gravity thickeners before the
process of drying the sludge (called
dewatering).
The next step is PRIMARY TREATMENT
Primary clarifiers are used to let the remaining
solids settle to the bottom of the structures to
make sludge. Submerged wiers will be used to
minimize odors. Sludge is pumped from the
primary clarifiers back to the grit removal
units and gravity thickeners. Scum and other
floating material is removed from the surface of
the clarifiers using surface skimmers with water
sprays. The scum flows into a hopper on the
outside of the clarifier and is transferred to
the scum concentrator in the Process Building
where it will be dropped into a truck and hauled
to a landfill or other disposal location.
The next step is SECONDARY TREATMENT
Secondary treatment utilizes trickling filters
and secondary clarifiers.
Large pumps lift the treated primary effluent
water to the top of the trickling filter
structures. The trickling filters are covered to
contain odors. The trickling filters contain a
plastic filter media. The water gravity flows
down over the filter media allowing
microorganisms to collect on the media and
consume most of the organic matter in the
wastewater. Large blowers force air across the
media to increase oxygen for the microorganisms.
From the trickling filters the treated water
flows on to the secondary clarifiers. Here the
remaining solids are allowed to settle to the
bottom for a second time. Scum removal is
similar to the primary clarifiers. Resulting
sludge is returned back to the degritting units
with the primary sludge. The treated water
(effluent) then flows out of the plant by way of
the plant outfalls.
EFFLUENT OUTFALL
The plant effluent will flow over a mile and one-
half to the Mississippi River at the confluence
of the Meramec River by way of an underground
pipe. A smaller portion of the plant effluent
will flow through a disinfection process to the
present Meramec Lagoon outfall of the wetland
preservation area. That discharge will help
preserve and enhance the ecology that has
developed around the existing Lagoon discharge
on the District’s property.
SOLIDS HANDLING
Solids handling includes sludge thickening,
sludge storage and blending, sludge dewatering,
and sludge cake storage and truck loading
facilities.
Dilute, degritted primary and trickling filter
sludge flows by gravity after degritting to the
gravity sludge thickeners. These sludge
thickeners are covered to control odor.
Thickened sludge is pumped to the
storage/blending tanks. The purpose of these
storage/blending tanks is to provide storage
that effectively allows separation of the liquid
process from dewatering and also to provide a
uniform flowrate and concentration of sludge to
the final dewatering process.
Sludge is then dewatered using machines called
belt presses. Each belt press is sized to handle
2,000 lbs. per hour. The presses will be located
in the Process Building and will discharge
directly to trailer trucks for disposal.
The loaded trucks will then transport the sludge
cake for disposal offsite.
ODOR CONTROL
The entire layout of this new plant has been
done to minimize the potential for odor
generation.
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Owner:
Metropolitan St. Louis Sewer District
Web site:
http://mkasmtp1.stlmsd.com/
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Operating Company:
Metropolitan St. Louis Sewer District
Web site:
http://mkasmtp1.stlmsd.com/
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Directions:
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Disclaimer:
Water and Wastewater.com provides the information on
this page for reference purposes only. We do not certify
the accuracy of the information provided by third-party
individuals for this listing.
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