Minn. R. agency 167, ch. 7053, EFFLUENT LIMITS AND TREATMENT REQUIREMENTS FOR DISCHARGES TO WATERS OF THE STATE, pt. 7053.0215
The agency shall require secondary treatment as a minimum for all municipal point source dischargers and other point source dischargers of sewage. For purposes of this part, "municipal" has the adjective meaning of municipality as defined in part 7001.1020, subpart 18. "Secondary treatment facilities" means works that will provide effective sedimentation, biochemical oxidation, and disinfection, or the equivalent, including effluents conforming to the following:
| Characteristic or Pollutant | Limiting Concentration or Range* |
| Five-day carbonaceous biochemical oxygen demand* | 25 mg/L |
| Fecal coliform group organisms ** | 200 organisms per 100 milliliters |
| Total suspended solids* | 30 mg/L |
| Oil | Essentially free of visible oil |
| Phosphorus | See part 7053.0255 |
| pH range | 6.0 - 9.0 |
| Toxic or corrosive pollutants | Concentrations of toxic or corrosive pollutants shall not cause acute toxicity to humans or other animals or plant life or directly damage real property or exceed the final acute value unless the effluent satisfies the whole effluent toxicity test. If a whole effluent toxicity test performed on the effluent results in less than 50 percent mortality of the test organisms, the effluent must not be considered acutely toxic unless the commissioner finds that the test species do not represent sensitive organisms in the affected surface water body or the whole effluent test was performed on a sample not representative of the effluent quality. The final acute value and whole effluent toxicity test are defined in part 7050.0218, subpart 3, items O and HH, respectively. |
*The arithmetic mean for concentrations of five-day carbonaceous biochemical oxygen demand and total suspended solids shall not exceed the stated values in any calendar month. In any calendar week, the arithmetic mean for concentrations of five-day carbonaceous biochemical oxygen demand shall not exceed 40 milligrams per liter and total suspended solids shall not exceed 45 milligrams per liter.
**Disinfection of wastewater effluents to reduce the levels of fecal coliform organisms to the stated value is required from April 1 through October 31 for Class 2 waters and May 1 through October 31 for Class 7 waters, except that where the effluent is discharged 25 miles or less upstream of a water intake supplying a potable water system, the reduction to the stated value is required all year. The stated value is not to be exceeded in any calendar month as determined by the geometric mean of all the samples collected in a given calendar month. The application of the fecal coliform group organism limit is limited to sewage or other effluents containing admixtures of sewage and do not apply to industrial wastes, except when the presence of sewage, fecal coliform organisms, or viable pathogenic organisms in such wastes is known or reasonably certain. Analysis of samples for fecal coliform group organisms by either the multiple tube fermentation or the membrane filter techniques is acceptable.
| Five-day carbonaceous biochemical oxygen demand | 40 mg/L* |
| Total suspended solids | 45 mg/L** |
*In any calendar week, the arithmetic mean for five-day carbonaceous biochemical oxygen demand shall not exceed 60 milligrams per liter.
**The arithmetic mean for any calendar week shall not exceed 65 milligrams per liter for total suspended solids.
| Total suspended solids | 45 mg/L* (arithmetic mean of all samples collected during any calendar month) |
*The arithmetic mean for any calendar week shall not exceed 65 milligrams per liter for total suspended solids.
Minn. R. agency 167, ch. 7053, EFFLUENT LIMITS AND TREATMENT REQUIREMENTS FOR DISCHARGES TO WATERS OF THE STATE, pt. 7053.0215
Statutory Authority: MS s 115.03; 115.44