4 STAR MHP STP
NPDES ID: IL0070351
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: 17 effluent violations.
Violations
May 31, 2026
Nitrogen, ammonia total [as N]
248% over limit
Discharged 0.3632 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Chlorine, total residual
880% over limit
Discharged 0.49 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
27% over limit
Discharged 0.3632 kg/d against a permitted limit of 0.28602 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
12% over limit
Discharged 3.7 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
208% over limit
Discharged 3.7 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
7% over limit
Discharged 0.3632 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2026
Nitrogen, ammonia total [as N]
147% over limit
Discharged 0.257418 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Chlorine, total residual
220% over limit
Discharged 0.16 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
183% over limit
Discharged 3.4 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
130% over limit
Discharged 921 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
3% over limit
Discharged 3.4 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Chlorine, total residual
980% over limit
Discharged 0.54 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
170% over limit
Discharged 27 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
85% over limit
Discharged 2.4 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
505% over limit
Discharged 2420 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
35% over limit
Discharged 27 mg/L against a permitted limit of 20 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
February 28, 2026
Nitrogen, ammonia total [as N]
38% over limit
Discharged 4 mg/L against a permitted limit of 2.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
82% over limit
Discharged 4 mg/L against a permitted limit of 2.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chlorine, total residual
100% over limit
Discharged 0.1 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
January 31, 2026
Nitrogen, ammonia total [as N]
91% over limit
Discharged 4.2 mg/L against a permitted limit of 2.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
325% over limit
Discharged 1700 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
45% over limit
Discharged 4.2 mg/L against a permitted limit of 2.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, ammonia total [as N]
9% over limit
Discharged 0.208386 kg/d against a permitted limit of 0.19068 kg/d (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2025
Nitrogen, ammonia total [as N]
508% over limit
Discharged 7.3 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
121% over limit
Discharged 7.3 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
426% over limit
Discharged 0.54934 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
87% over limit
Discharged 7.3 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
61% over limit
Discharged 0.54934 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Coliform, fecal general
500% over limit
Discharged 2400 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
92% over limit
Discharged 0.54934 kg/d against a permitted limit of 0.28602 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
September 30, 2025
Nitrogen, ammonia total [as N]
492% over limit
Discharged 7.1 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chlorine, total residual
760% over limit
Discharged 0.43 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
82% over limit
Discharged 7.1 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Coliform, fecal general
250% over limit
Discharged 1400 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
115% over limit
Discharged 7.1 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
40% over limit
Discharged 0.39952 kg/d against a permitted limit of 0.28602 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
17% over limit
Discharged 0.39952 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
283% over limit
Discharged 0.39952 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2025
Nitrogen, ammonia total [as N]
297% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.09534 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
809% over limit
Discharged 10 mg/L against a permitted limit of 1.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.24516 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
257% over limit
Discharged 10 mg/L against a permitted limit of 2.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
11% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Chlorine, total residual
100% over limit
Discharged 0.1 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
156% over limit
Discharged 10 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
July 31, 2025
Nitrogen, ammonia total [as N]
141% over limit
Discharged 9.4 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
755% over limit
Discharged 9.4 mg/L against a permitted limit of 1.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chlorine, total residual
100% over limit
Discharged 0.1 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
236% over limit
Discharged 9.4 mg/L against a permitted limit of 2.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
5950% over limit
Discharged 24200 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
86% over limit
Discharged 0.17706 kg/d against a permitted limit of 0.09534 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
67% over limit
Discharged 0.4086 kg/d against a permitted limit of 0.24516 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Nitrogen, ammonia total [as N]
182% over limit
Discharged 7.9 mg/L against a permitted limit of 2.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
43% over limit
Discharged 1.49819999 kg/d against a permitted limit of 1.0442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
2% over limit
Discharged 5.9 mg/L against a permitted limit of 6 mg/L (MN WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
618% over limit
Discharged 7.9 mg/L against a permitted limit of 1.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
103% over limit
Discharged 7.9 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
76% over limit
Discharged 0.59927999 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
529% over limit
Discharged 0.59927999 kg/d against a permitted limit of 0.09534 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
67% over limit
Discharged 20 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
144% over limit
Discharged 0.59927999 kg/d against a permitted limit of 0.24516 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
May 31, 2025
Nitrogen, ammonia total [as N]
310% over limit
Discharged 16 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
256% over limit
Discharged 1.21217999 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Coliform, fecal general
127% over limit
Discharged 908 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
5% over limit
Discharged 5.7 mg/L against a permitted limit of 6 mg/L (MN WK AV)
DMR, Limited - Numeric Violation
Solids, total suspended
30% over limit
Discharged 1.36199999 kg/d against a permitted limit of 1.0442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
385% over limit
Discharged 16 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1233% over limit
Discharged 16 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1061% over limit
Discharged 1.21217999 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
50% over limit
Discharged 18 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
324% over limit
Discharged 1.21217999 kg/d against a permitted limit of 0.28602 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
April 30, 2025
Nitrogen, ammonia total [as N]
172% over limit
Discharged 0.284204 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
21% over limit
Discharged 4 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
150% over limit
Discharged 3 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Coliform, fecal general
505% over limit
Discharged 2420 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
577% over limit
Discharged 8.8 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
167% over limit
Discharged 8.8 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
100% over limit
Discharged 8.8 mg/L against a permitted limit of 4.4 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
48% over limit
Discharged 0.16798 kg/d against a permitted limit of 0.1135 kg/d (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Nitrogen, ammonia total [as N]
7% over limit
Discharged 3.1 mg/L against a permitted limit of 2.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
41% over limit
Discharged 3.1 mg/L against a permitted limit of 2.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 0.293284 kg/d against a permitted limit of 0.19068 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
15% over limit
Discharged 0.293284 kg/d against a permitted limit of 0.25424 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
January 31, 2025
Nitrogen, ammonia total [as N]
116% over limit
Discharged 0.54934 kg/d against a permitted limit of 0.25424 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
188% over limit
Discharged 0.54934 kg/d against a permitted limit of 0.19068 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
164% over limit
Discharged 5.8 mg/L against a permitted limit of 2.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
100% over limit
Discharged 5.8 mg/L against a permitted limit of 2.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Coliform, fecal general
505% over limit
Discharged 2420 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2024
Coliform, fecal general
505% over limit
Discharged 2420 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
9% over limit
Discharged 0.94431999 kg/d against a permitted limit of 0.8626 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
124% over limit
Discharged 6.5 mg/L against a permitted limit of 2.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
195% over limit
Discharged 6.5 mg/L against a permitted limit of 2.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
143% over limit
Discharged 0.61743999 kg/d against a permitted limit of 0.25424 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
224% over limit
Discharged 0.61743999 kg/d against a permitted limit of 0.19068 kg/d (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2024
Nitrogen, ammonia total [as N]
73% over limit
Discharged 3.8 mg/L against a permitted limit of 2.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
31% over limit
Discharged 3.8 mg/L against a permitted limit of 2.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
October 31, 2024
Coliform, fecal general
Limit violation
Discharged 24000 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
285% over limit
Discharged 15 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
74% over limit
Discharged 1.49819999 kg/d against a permitted limit of 0.8626 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
987% over limit
Discharged 1.13499999 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
297% over limit
Discharged 1.13499999 kg/d against a permitted limit of 0.28602 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
100% over limit
Discharged 20 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
233% over limit
Discharged 1.13499999 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1150% over limit
Discharged 15 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
355% over limit
Discharged 15 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
September 30, 2024
BOD, carbonaceous [5 day, 20 C]
900% over limit
Discharged 100 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
10% over limit
Discharged 1.89317998 kg/d against a permitted limit of 1.7252 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
32% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.28602 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
506% over limit
Discharged 20 mg/L against a permitted limit of 3.3 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
42% over limit
Discharged 17 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
119% over limit
Discharged 1.89317998 kg/d against a permitted limit of 0.8626 kg/d (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
400% over limit
Discharged 100 mg/L against a permitted limit of 20 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
11% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
263% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.10442 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 24200 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
413% over limit
Discharged 20 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1567% over limit
Discharged 20 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2024
Solids, total suspended
42% over limit
Discharged 17 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
413% over limit
Discharged 20 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1718% over limit
Discharged 20 mg/L against a permitted limit of 1.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
10% over limit
Discharged 11 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.24516 kg/d (WKLY AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
297% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.09534 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
505% over limit
Discharged 2420 MPN/100mL against a permitted limit of 400 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
11% over limit
Discharged 0.378636 kg/d against a permitted limit of 0.3405 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
614% over limit
Discharged 20 mg/L against a permitted limit of 2.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (4 days ago)