RISON, CITY OF WWZTP
NPDES ID: AR0021695
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: 12 effluent violations.
Violations
June 30, 2026
Nitrogen, ammonia total [as N]
19% over limit
Discharged 5.58419995 kg/d against a permitted limit of 4.67619996 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
48% over limit
Discharged 2.58 mg/L against a permitted limit of 5 mg/L (INST MIN)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 2400 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
483% over limit
Discharged 35 mg/L against a permitted limit of 6 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
428% over limit
Discharged 21.1 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 1287 MPN/100mL against a permitted limit of 1000 MPN/100mL (30DA GEO)
DMR, Limited - Numeric Violation
Solids, total suspended
5% over limit
Discharged 21 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2026
Nitrogen, ammonia total [as N]
3067% over limit
Discharged 190 mg/L against a permitted limit of 6 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 2400 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
2650% over limit
Discharged 110 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
622% over limit
Discharged 33.77759972 kg/d against a permitted limit of 4.67619996 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
42% over limit
Discharged 2.89 mg/L against a permitted limit of 5 mg/L (INST MIN)
DMR, Limited - Numeric Violation
January 31, 2026
Nitrogen, ammonia total [as N]
824% over limit
Discharged 130.02559891 kg/d against a permitted limit of 14.07399988 kg/d (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
314% over limit
Discharged 97.11059918 kg/d against a permitted limit of 23.4717998 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
2% over limit
Discharged 17.4 mg/L against a permitted limit of 17 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
323% over limit
Discharged 99.28979917 kg/d against a permitted limit of 23.4717998 kg/d (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2025
Solids, total suspended
11% over limit
Discharged 33.2 mg/L against a permitted limit of 30 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
50% over limit
Discharged 6 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
93% over limit
Discharged 11.6 mg/L against a permitted limit of 6 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
58% over limit
Discharged 31.6 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 1000 MPN/100mL (30DA GEO)
DMR, Limited - Numeric Violation
June 30, 2025
Coliform, fecal general
Limit violation
Discharged 9208 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Coliform, fecal general
372% over limit
Discharged 4720.1 MPN/100mL against a permitted limit of 1000 MPN/100mL (30DA GEO)
DMR, Limited - Numeric Violation
Solids, total suspended
7% over limit
Discharged 21.3 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2025
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
29% over limit
Discharged 7.73 mg/L against a permitted limit of 6 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
90% over limit
Discharged 7.58 mg/L against a permitted limit of 4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
April 30, 2025
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
March 31, 2025
Nitrogen, ammonia total [as N]
33% over limit
Discharged 15.9 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
6% over limit
Discharged 18.1 mg/L against a permitted limit of 17 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
39% over limit
Discharged 27.8 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
7% over limit
Discharged 21.4 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
12% over limit
Discharged 33.6 mg/L against a permitted limit of 30 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
33% over limit
Discharged 40 mg/L against a permitted limit of 30 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Solids, total suspended
132% over limit
Discharged 69.6 mg/L against a permitted limit of 30 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Solids, total suspended
141% over limit
Discharged 48.2 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2024
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 1000 MPN/100mL (30DA GEO)
DMR, Limited - Numeric Violation
Solids, total suspended
16% over limit
Discharged 23.2 mg/L against a permitted limit of 20 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Coliform, fecal general
21% over limit
Discharged 2419.6 MPN/100mL against a permitted limit of 2000 MPN/100mL (7 DA GEO)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
6% over limit
Discharged 4.7 mg/L against a permitted limit of 5 mg/L (INST MIN)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (4 months ago)
Last confirmed
August 15, 2026 (8 hours ago)