CAIRO STP, CITY OF
NPDES ID: IL0023825
X — SNC: Effluent violation (non-monthly average limit)
The facility discharged more of a pollutant than its permit allows, measured over a period other than a monthly average.
This quarter: 2 effluent violations.
Violations
May 31, 2026
Nitrogen, ammonia total [as N]
49% over limit
Discharged 6.99 mg/L against a permitted limit of 4.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2026
Nitrogen, ammonia total [as N]
100% over limit
Discharged 9.4 mg/L against a permitted limit of 4.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2026
Nitrogen, ammonia total [as N]
45% over limit
Discharged 6.82 mg/L against a permitted limit of 4.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
4% over limit
Discharged 6 mg/L against a permitted limit of 6.25 mg/L (MN WK AV)
DMR, Limited - Numeric Violation
February 28, 2026
Nitrogen, ammonia total [as N]
92% over limit
Discharged 11.5 mg/L against a permitted limit of 6 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 1.15 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)