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December 2019
A fire at an auto body and repair shop in Orr, Minn., could have led to significant impacts at the city’s wastewater treatment facility and downstream receiving waters, if not for the quick-thinking operators at the city’s treatment facility.
Early in the morning of Sept. 23, 2019, fire engulfed an auto body and repair shop in this town of 282 people in northern Minnesota. Firefighters arrived and were able to keep the flames from spreading to an adjacent motel, but the shop was a total loss. Floor drains within the shop allowed firefighting foam and water to drain to the sanitary sewer, along with several hundred gallons of used oil.
By 8 a.m. that morning, Paul Koch, Class B certified wastewater operator and maintenance supervisor (photo on left above), and Rocky Hoffman, assistant maintenance worker (photo above right), had identified oil within components of the Orr wastewater treatment plant: Imhoff tank, trickling filter, secondary clarifier, and chlorine contact tank. They shut off the main lift station pumps to reduce impacts to the plant, called the Minnesota Duty Officer to report the possible plant upset, and then contacted MPCA emergency response and wastewater staff to determine next steps.
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By early afternoon, an environmental contractor had mobilized a 20,000-gallon frac tank to the plant and a local septage hauler was on-site pumping influent from the main lift station and skimming oil from the Imhoff tank, secondary clarifier and chlorine contact tank to the frac tank. Over the next two days, about 18,000 gallons was pumped to the frac tank. Absorbent booms were placed within treatment components as well as at the plant’s outfall to a ditch to the Pelican River.
Firefighters had used a Class A fire suppressant foam that the manufacturer reported as having no PFAS (per- and polyfluoroalkyl substances) compounds. Sampling of wastewater within the frac tank showed that pollutant concentrations were acceptable for treatment at the wastewater treatment plant. Over a week-long period the wastewater was discharged to the head of the plant. The oil layer within the frac tank was pumped to six 250-gallon totes and one 55-gallon drum for incineration in Memphis, Tenn.
Koch and Hoffman conducted the monitoring required by their NPDES permit twice during the next two days following the fire. (They usually sample only once a week as required by the city’s permit). The results indicated no plant upset, with monitoring results just after the fire being similar to results prior to the fire. The plant reported no effluent limit violations for the month.
“The City of Orr, and especially its wastewater operator and maintenance worker, did commendable work responding to the incident and minimizing impacts,” said John Thomas, MPCA compliance officer.
This was especially true because Koch responded to the emergency while recovering from knee surgery. He coordinated the response while on crutches or from his wheelchair.
“This is another example of small town wastewater operators rising to the challenge of keeping systems operating, even in the worst of times,” Thomas said.
Photo above right: Part of the response at the Orr WWTF included pumping influent to a frac tank and skimming oil off treatment components to minimize system upset or pollutant pass-through to the receiving water.
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The MPCA is proposing to change the phosphorus limit types in the Wastewater General Pond Permit (MNG585) from a “12 Month Moving Total” to a “Calendar Year to Date Total.” This change is on public notice through Dec. 30. "Calendar Year to Date Total" is a total of all samples taken during one calendar year.The MPCA is proposing the change because the “Calendar Year to Date Total” is easier to calculate and more representative of wastewater pond operations in the long run.
What is changing?
The Wastewater General Pond Permit (MNG585) is currently on public notice for a modification to change the mass limit type for phosphorus to a “Calendar Year to Date Total.” Previously, if a facility had a mass limit, it was a “12 Month Moving Total.” Moving forward, these limits types will change to a “Calendar Year to Date Total.”
Who is affected?
All permittees who have a “12 Month Moving Total” will see a change to the “Calendar Year to Date Total.” Permittees issued a notice of coverage (NOC) under Batch 1 in December of 2018 will be receiving a modified permit in January 2020. Permittees who are issued NOCs moving forward will see the new limit type in their issued NOC.
Why is this changing?
A “12 Month Moving Total” is not an optimal limit type for controlled discharge facilities. Stabilization ponds typically discharge once or twice a season with very few of those days being in the summer period. Stabilization ponds in Minnesota operate with restrictive discharge windows that prohibit discharge in January and February, and allow very limited to no discharge in the summer months. Multiple compliance points are not necessary given the number of months that no discharge occurs. In short, the "12-Month Moving Total" limit type was not providing the data the MPCA needs and adds further complications for the operators working with seasonal variability and discharge timing.
What does an operator need to do when the new modified permit becomes effective or when the permit is reissued?
The calculator tool starts with the effective date of the permit. It is likely that both the Batch 1 modifications and Batch 2 issuances of NOCs will become effective Feb. 1, 2020. Because most wastewater pond facilities do not discharge in January, the calculation will start with the spring discharges, following the instructions below:
"Calendar Year to Date Total" is a total of all samples taken during one calendar year.
To calculate:
- Add all sample values measured from the first of the calendar year to the end date of the current reporting period.
- When used for loading values (kg/year), first calculate the calendar month total kg/month loading by multiplying the calendar month total effluent flow x calendar month average concentration x 3.785.
- Then add all loading values from the first of the calendar year to the end date of the current reporting period.
- Use the flow from the SD station.
- If there is no flow from the SD station, check the "No Discharge/No Flow" box on the eDMR.
If you have any questions about how this change or how to calculate it, please contact your MPCA compliance staff.
Representatives from several cities and industries in southwest Minnesota met with MPCA staff on Nov. 21 in Worthington to talk about wastewater treatment issues and broader water quality issues in the Des Moines River watershed.
Topics included river eutrophication standards, chloride standards, regional Total Maximum Daily Loads (TMDLs), future permit limits, and opportunities for water quality trading.
“This watershed meeting provided an opportunity for the MPCA to communicate with permit holders about local water quality and NPDES permitting considerations. It was also an opportunity for communities and industries to ask questions and better understand factors impacting their permits,” said Joel Peck, MPCA liaison with municipal wastewater entities. "We appreciate everyone’s time and efforts on these important topics. We also thank the city of Worthington for hosting."
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As a result of a recent federal rule change to determining method detection limits, the MPCA updated its Total Residual Chlorine method detection and reporting guidance. Permittees are required to analyze and document at least eight method blanks and laboratory control samples at or below the permit required reporting limit throughout the year during disinfection season. Guidance on this procedure is located at www.pca.state.mn.us/sites/default/files/wq-wwtp1-11.pdf. Below are actions you should take to prepare for the 2020 disinfection season.
- Review laboratory equipment to ensure you have access to:
- Proper labware (e.g. volumetric flask) to prepare control sample
- Access to method blank (e.g. distilled water)
- Standard to prepare laboratory control sample
- Establish a recordkeeping standard practice to document analysis
If you have questions, please contact your MPCA compliance staff.
The wastewater training calendar for 2020 is available on the Wastewater Operators Training and Certification page at this link: www.pca.state.mn.us/sites/default/files/p-tr2-10.pdf. Please note: The Annual Wastewater Conference brochures and registration are separate from the calendar. You may also access wastewater training offered monthly at the following link: https://www.pca.state.mn.us/water/wastewater-operator-training.
The MPCA will hold the 46th annual Collection System Conference March 23-25, 2020 at the Marriott Northwest in Brooklyn Park (7025 Northland Drive North, Brooklyn Park, Minn.). The conference brochure and registration packet will be available on the MPCA Wastewater Training webpage in January 2020.
Highlights include:
- SA and SB exam refresher
- SC and SD exam refresher
- Certification examinations
- Vendor and professional organization displays
The MPCA will hold the 83rd annual Wastewater Operations Conference March 25-27, 2020 at the Marriott Northwest in Brooklyn Park (7025 Northland Drive North, Brooklyn Park, Minn.). The conference brochure and registration packet will be available on the MPCA Wastewater Training webpage in January 2020.
Highlights include:
- A and B exam refresher
- C and D exam refresher
- Type IV (biosolids) refresher
- Certification examinations
- Vendor and professional organization displays
- Facility Operational Awards ceremony
This is a reminder to send in your year-end submittals electronically to the electronic WQ Submittals at: wq.submittals.mpca@state.mn.us.
Follow these easy steps:
NOTE: The MPCA will not deem the WQ Submittal as received unless the form is attached.
The ONLY EXCEPTIONS to this electronic submittal process are:
- Pretreatment Annual Reports
- Whole Effluent Toxicity Tests (WET Tests)
These must still be submitted as paper copies to:
Minnesota Pollution Control Agency
Attention: WQ Submittals Center
520 Lafayette Road North
St. Paul, MN 55155-4194
If you have any questions regarding this new process, please contact your assigned MPCA data manager or compliance staff person.
In last month's story about the energy assessments offered by the Minnesota Rural Water Association, the phone number for the contact was incorrect. Here is the right name and phone number: Paul Hoeschen at 218-820-0479 or paul.hoeschen@mrwa.com.
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