NIANGUA WWTP
NPDES ID: MO0095109
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: 10 effluent violations.
Violations
June 30, 2026
BOD, 5-day, percent removal
13% over limit
Discharged 83 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
46% over limit
Discharged 1.9 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2026
BOD, 5-day, 20 deg. C
33% over limit
Discharged 40 mg/L against a permitted limit of 30 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
213% over limit
Discharged 15 mg/L against a permitted limit of 4.8 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1054% over limit
Discharged 15 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
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, 5-day, percent removal
67% over limit
Discharged 75 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
April 30, 2026
Nitrogen, ammonia total [as N]
392% over limit
Discharged 6.4 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, 5-day, percent removal
7% over limit
Discharged 84 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
33% over limit
Discharged 6.4 mg/L against a permitted limit of 4.8 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2026
Solids, suspended percent removal
47% over limit
Discharged 78 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
BOD, 5-day, percent removal
47% over limit
Discharged 78 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
March 31, 2025
Nitrogen, ammonia total [as N]
161% over limit
Discharged 6 mg/L against a permitted limit of 2.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Nitrogen, ammonia total [as N]
465% over limit
Discharged 13 mg/L against a permitted limit of 2.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
7% over limit
Discharged 13 mg/L against a permitted limit of 12.1 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2024
Nitrogen, ammonia total [as N]
943% over limit
Discharged 24 mg/L against a permitted limit of 2.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, suspended percent removal
13% over limit
Discharged 83 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
98% over limit
Discharged 24 mg/L against a permitted limit of 12.1 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2024
Nitrogen, ammonia total [as N]
191% over limit
Discharged 6.7 mg/L against a permitted limit of 2.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2024
Solids, suspended percent removal
16% over limit
Discharged 82.6 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
40% over limit
Discharged 17 mg/L against a permitted limit of 12.1 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
639% over limit
Discharged 17 mg/L against a permitted limit of 2.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Nitrogen, ammonia total [as N]
442% over limit
Discharged 26 mg/L against a permitted limit of 4.8 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1900% over limit
Discharged 26 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, suspended percent removal
67% over limit
Discharged 75 % against a permitted limit of 85 % (MO AV MN)
DMR, Limited - Numeric Violation
August 31, 2024
Nitrogen, ammonia total [as N]
1746% over limit
Discharged 24 mg/L against a permitted limit of 1.3 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
400% over limit
Discharged 24 mg/L against a permitted limit of 4.8 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (4 months ago)
Last confirmed
August 16, 2026 (3 hours ago)