Primary & Secondary Treatment Remains Fully Functioning Advisory to Avoid Contact with the Meramec River between the City of Fenton & the Mississippi
Metropolitan St. Louis Sewer District (MSD) crews and contractors have made progress in restoring the ultraviolet light (UV) treatment process at the Fenton Wastewater Treatment Plant (WWTP). (UV treatment is required during the recreation season from April 1 through October 31. UV treatment is not required from November 1 through March 31.) Early assessments indicate that parts of the UV treatment process will be salvageable. In the meantime, a temporary chemical based process that replicates the function of the UV treatment process is being put in place. MSD projects this temporary process will become operational over the weekend. However, before the advisory for the Meramec River can be lifted, MSD must conduct testing to verify the chemical based process is functioning as planned and the treatment facility is meeting regulatory requirements.
While there is no immediate threat to the public’s health or safety, MSD has issued an advisory to avoid contact with the Meramec River from Fenton, Missouri, to the Mississippi River. Signs have been posted in areas where the public may readily come into contact with this section of the river. If anyone should come into contact with the river in this area, it is recommended they immediately and thoroughly wash with soap and water.
Once water quality testing verifies the treatment facility is meeting regulatory requirements, MSD will lift the advisory for the Meramec River. Based on current assessments and progress, MSD expects to lift the advisory sometime next week (the week of August 22.)
A timeline for repairs to the UV treatment system will be issued with future updates.
On Monday, August 15, a cloudburst of nearly four inches of rain fell on south St. Louis County over six hours. This rainwater made its way into the sewer system leading to MSD’s Fenton Wastewater Treatment Plant, located in Fenton, MO. The rainwater inundated the treatment processes at the plant and flooded the UV treatment building located at the rear of the treatment facility. During this time, the primary and secondary treatment processes remained online and fully functional.
While the rains of August 15 did not cause the same amount of damage to the Fenton WWTP as the rains and flooding of December 2015/January 2016 – when record floodwaters from the Meramec River topped the plant’s flood protection levee, covered the facility in six feet of water, and took the treatment facility offline until April 8, 2016 – final repairs from the flooding were still being completed. This ongoing recovery from the flooding did contribute to the flooding of the UV treatment building on August 15. Due to the very high volume of rainwater that came into the Fenton WWTP on August 15, MSD is also working to identify if a potential break or damage to the sewer system occurred during the August 15 rains.
MSD has begun weekly water quality monitoring of the Meramec River near the Fenton WWTP. As shown below, one sample is taken upstream of the Fenton WWTP and several more samples are taken downstream of the plant. These results are impacted by a number of factors aside from the functioning of the treatment plant, including the volume of the river at the time of the tests; the timing, amount, and locations of recent rainfalls; turbidity of the river; the amount of sunlight the river is exposed to; and other environmental factors. This past week’s results:
|
Date |
Parameter |
units |
USGS Gauging Station, Eureka |
MoAM South Plant |
GWP |
Schmussler Rd. End |
Corisande Hill Rd. |
21 Bridge |
Edgwood Beach Rd. |
Lemay Ferry Bridge |
Arnold Park, Lower End |
Telegraph Bridge |
|
UP-1 |
DS-1 |
DS-2 |
DS-3 |
DS-4 |
DS-5 |
DS-6 |
DS-7 |
DS-8 |
||||
|
8/16/2016 |
E. Coli |
colonies/100 mL |
|
2282 |
2851 |
2987 |
2400 |
2909 |
2723 |
3441 |
2481 |
2603 |
|
pH |
std units |
7.95 |
7.94 |
7.88 |
7.95 |
7.93 |
7.92 |
7.8 |
7.85 |
7.9 |
||
|
Dissolved Oxygen (mg/L) |
mg/L |
7.18 |
6.92 |
6.85 |
6.88 |
6.67 |
6.81 |
6.78 |
6.33 |
6.7 |
||
|
Temperature |
°C |
23.53 |
23.52 |
23.73 |
23.74 |
23.81 |
23.9 |
23.96 |
23.98 |
24.05 |
||
|
cfs |
14400 |
|
|
|
|
|
|
|
|
|
Wastewater service to area homes and businesses has not and will not be interrupted.
Pictures of the flooded UV treatment building are available @ https://www.dropbox.com/sh/3inr5fy6a7igocj/AACDSkJK_O8Wg7L9voe6KH_ga?dl=0
Primary treatment is the first step in the treatment process when any treatment plant is fully operating. Primary treatment involves the removal of solids from the wastewater. The next step of a fully functioning treatment process is called secondary treatment. This step utilizes biological processes to remove pollutants from the wastewater. The third step, in effect at the Fenton WWTP from April 1 through October 31, is the ultraviolet light treatment process.
The Fenton Wastewater Treatment Plant is designed to handle 6.75 million gallons of wastewater per day during dry conditions. During wet weather conditions, the plant can handle up 24 million gallons per day.
MSD has notified and been in constant contact with the Missouri Department of Natural Resources about the situation at the Fenton Wastewater Treatment Plant, as required by law. Additionally, MSD has been in contact with various governmental agencies and drinking water utilities located along the Meramec River in both Jefferson County and St. Louis County.
MSD will share further information on this situation as it becomes available.