The city of Paynesville has applied for a permit to pump benzene contaminated water into the cityís storm sewer system. The storm sewers flow into the North Fork Crow River.
At present, the city is pumping 100 gallons a minute into the sanitary sewer system at city hall. ďThe system canít handle the excess water over a period of time,Ē Ron Mergen, public works director, told the council.
The city has requested authorization to use the plume as a containment well. The city would pump well number four behind city hall, without treatment, to the storm sewer. The plume is the area of contaminated ground water.
The purpose of the discharge is to control the direction of the plume and to prevent petroleum contamination from impacting the three other municipal wells.
At present, the city is pumping 400 gallons per minute from wells five and six (located south of Highway 23 near Paynesville Greenhouse) into the city pretreatment plant for homeowner use. Because of benzene contamination, well three (on Minnie Street near the city garages) is pumping 100 gallons per minute instead of the 400 gallons per minute last fall before the contamination was discovered.
When well three was pumping at a larger capacity, it was drawing the contamination away from pump four. By cutting back the pumping capacity, contamination levels have dropped.
Known pollutant levels in well number four do not exceed effluent levels contained in the general permit, under which the city is currently discharging. The last test of well number four showed the contamination levels at nine parts per billion (ppb), compared to 17 ppb in January. Well number three tested at five ppb.This compares to 17 ppb in January.
Hazardous waste staff believe that pumping at a rate as high as 300,000 gallons per day may be necessary to protect the cityís drinking water supply. As this level exceeds the 50 gallons per minute (gpm) restriction in the general permit, MPCA staff are proposing authorization for this discharge under this individual permit.
Routine testing showed the contamination source is from a former gas station at Mill Street and Lake Street. The storage tank was removed in 1989 from the former service station. Further testing this spring has pin-pointed the contamination source.
James McArthur, hydrologist with the MPCA, will be suggesting to the council at the public hearing on July 8 that a well be installed in the heart of the plume area. This well would pump 10 to 20 gallons per minute into the sanitary sewer system as the contamination would be too high for the storm sewer system, Ron Mergen, Paynesville Public Works Director, said.
Mergen said the best way to treat the contaminated water is by aeration. By pumping the contaminated water into the storm sewer, once the benzene comes into contact with open air, it will dissipate (lose strength) before it reaches the North Fork Crow River.
The permit is for a term of about five years.
A draft of the permit is available for review at the MPCA central office at St. Paul from Deborah A. Schumann, Point Source Compliance Section, Water Quality Division, MPCA 520 Lafayette Road North, St. Paul, 55155-4194, or at the MPCA regional office at 1601 Minnesota Drive, Brainerd, MN 56401, or by calling 218-828-2492.
A copy of the draft permit will be mailed after the MPCA receives either a written or oral request.
The public comment period is from June 15 to July 15. Comments can be made by sending them to the above address as well.
Pete Carlson, city engineer, informed the council that hopefully by the Fourth of July, the sod work would be completed on the 1998 street project.
ďAll the streets are paved and they are back filling black dirt behind the curbs,Ē Carlson said. ďThe sod work is expected to start on Monday, June 29. Soon after the sod work is done, crews will start laying the second layer of tar.Ē
ďThe construction crew found a couple of soft spots on Augusta, but they werenít as bad as anticipated,Ē Carlson told the council.
Carlson said the pumps have been installed at the new lift station between Highways 55 and 23 on the west end of Paynesville. The control panel is expected to arrive shortly, he added, then work can begin on repairing the roadway by the lift station.
In other business:
ēThe council approved a step increase for Marilyn Fuchs as she has completed her six-month probationary period as liquor store manager.
ēThe council approved additional concrete work on the boulevards along Highway 23. An error was made in calculation plus two more residents have requested their sod boulevards be removed and concrete poured instead. Total cost of the project is $13,500.
ēThe council approved a resolution with MnDOT for a grant for their participation in and reimbursement for the airport studies the council has approved.
ēDennis Wilde, city administrator, informed the council that in July he will be starting the 1999 budget process. Anyone with budget requests need to submit their requests to him.
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