ZIMMERMAN WWTP
NPDES ID: MN0042331
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
This quarter: 5 effluent violations.
Violations
May 31, 2026
Phosphorus, total [as P]
16% over limit
Discharged 1.33621576 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
April 30, 2026
Phosphorus, total [as P]
26% over limit
Discharged 1.44756935 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
10% over limit
Discharged 1.1 mg/L against a permitted limit of 1 mg/L (12MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
140% over limit
Discharged 38.7 kg/d against a permitted limit of 16.1 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
243% over limit
Discharged 32.2 mg/L against a permitted limit of 9.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Phosphorus, total [as P]
10% over limit
Discharged 1.1 mg/L against a permitted limit of 1 mg/L (12MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
40% over limit
Discharged 37.2 kg/d against a permitted limit of 26.6 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
27% over limit
Discharged 1.45543315 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
91% over limit
Discharged 29.8 mg/L against a permitted limit of 15.6 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Phosphorus, total [as P]
10% over limit
Discharged 1.1 mg/L against a permitted limit of 1 mg/L (12MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
17% over limit
Discharged 31.2 kg/d against a permitted limit of 26.6 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
28% over limit
Discharged 1.47244855 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
20% over limit
Discharged 18 mg/L against a permitted limit of 15 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
53% over limit
Discharged 23.9 mg/L against a permitted limit of 15.6 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2026
Phosphorus, total [as P]
20% over limit
Discharged 1.37989135 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
December 31, 2025
Phosphorus, total [as P]
18% over limit
Discharged 1.36030035 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
November 30, 2025
Phosphorus, total [as P]
11% over limit
Discharged 1.27149696 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
September 30, 2025
Nitrogen, ammonia total [as N]
18% over limit
Discharged 2.6 kg/d against a permitted limit of 2.2 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 2 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Nitrite + Nitrate total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (QRTR AVG)
DMR, Monitor Only - Overdue
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (QRTR AVG)
DMR, Monitor Only - Overdue
Nitrogen, Kjeldahl, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (QRTR AVG)
DMR, Monitor Only - Overdue
Nitrite + Nitrate total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (QRTR AVG)
DMR, Monitor Only - Overdue
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (QRTR AVG)
DMR, Monitor Only - Overdue
Nitrogen, Kjeldahl, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (QRTR AVG)
DMR, Monitor Only - Overdue
April 30, 2025
Nitrogen, ammonia total [as N]
80% over limit
Discharged 29 kg/d against a permitted limit of 16.1 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
148% over limit
Discharged 23.3 mg/L against a permitted limit of 9.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Solids, total dissolved
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO MAX)
DMR, Monitor Only - Overdue
Nitrogen, ammonia total [as N]
53% over limit
Discharged 40.8 kg/d against a permitted limit of 26.6 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
65% over limit
Discharged 127 kg/d against a permitted limit of 77 kg/d (MX WK AV)
DMR, Limited - Numeric Violation
Solids, total suspended
96% over limit
Discharged 88 mg/L against a permitted limit of 45 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
37% over limit
Discharged 59 kg/d against a permitted limit of 43 kg/d (MX WK AV)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
64% over limit
Discharged 41 mg/L against a permitted limit of 25 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
104% over limit
Discharged 31.9 mg/L against a permitted limit of 15.6 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Nitrogen, ammonia total [as N]
35% over limit
Discharged 21 mg/L against a permitted limit of 15.6 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
10% over limit
Discharged 29.2 kg/d against a permitted limit of 26.6 kg/d (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2024
Solids, total suspended
88% over limit
Discharged 96 kg/d against a permitted limit of 51 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
478% over limit
Discharged 260 mg/L against a permitted limit of 45 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Solids, total suspended
130% over limit
Discharged 69 mg/L against a permitted limit of 30 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
568% over limit
Discharged 167 mg/L against a permitted limit of 25 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Solids, suspended percent removal
73% over limit
Discharged 74 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
131% over limit
Discharged 60 kg/d against a permitted limit of 26 kg/d (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
187% over limit
Discharged 43 mg/L against a permitted limit of 15 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carb-5 day, 20 deg C, percent removal
40% over limit
Discharged 79 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
Solids, total suspended
370% over limit
Discharged 362 kg/d against a permitted limit of 77 kg/d (MX WK AV)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
442% over limit
Discharged 233 kg/d against a permitted limit of 43 kg/d (MX WK AV)
DMR, Limited - Numeric Violation
October 31, 2024
Phosphorus, total [as P]
1% over limit
Discharged 1.15932136 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
September 30, 2024
Phosphorus, total [as P]
12% over limit
Discharged 1.28651216 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
August 31, 2024
Phosphorus, total [as P]
13% over limit
Discharged 1.29769136 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
July 31, 2024
Phosphorus, total [as P]
13% over limit
Discharged 1.30149996 kg/d against a permitted limit of 1.14805996 kg/d (ANNL TOT)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (24 days ago)