How much wastewater does Ossian City Of STP treat?

Ossian City Of STP treats an average of 0.18 MGD and is permitted for a design flow of 0.44 MGD.

What treatment technology does Ossian City Of STP use?

Klarifi has identified 2 treatment structures and unit processes at the Ossian facility. The full treatment train, with exact unit counts, is shown in Klarifi with a free account.

What is the NPDES permit for Ossian City Of STP?

The facility discharges under NPDES permit IA0042781, currently administratively continued, expiring September 2006.

Is Ossian City Of STP in compliance?

Discharge monitoring reports show 5 violations at Ossian City Of STP in the last three years, 5 of them effluent limit exceedances. The full history is available in Klarifi.

Who operates Ossian City Of STP and how do I contact them?

Ossian City Of STP is a publicly owned treatment works in Ossian, Iowa. Klarifi lists 1 verified decision-maker contact for this facility, available with a free trial.

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Ossian City Of STP

Ossian, IA 52161 · Winneshiek County · Publicly Owned Treatment Works

Average flow: 0.18 MGD

Design flow: 0.44 MGD

NPDES permit: IA0042781; Administratively continued

Permit expires: September 2006

Population served: 847; CWNS 2022

Ossian City Of STP is a publicly owned wastewater treatment works in Ossian, Winneshiek County, Iowa treating an average of 0.18 million gallons per day against a permitted design capacity of 0.44 MGD, serving about 847 residents. It discharges under NPDES permit IA0042781 (administratively continued), which expires in September 2006, with 5 recorded violations in the last three years.

Treatment technology

2 treatment structures and unit processes identified at Ossian City Of STP.

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See the full treatment train at Ossian City Of STP: structures, unit processes and planned upgrades, with exact unit counts.

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Compliance snapshot (last 3 years)

Total violations: 5

Effluent violations: 5

Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.

Key contacts

1 verified contact for Ossian City Of STP, with validated emails and direct phone numbers.

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Names, validated emails and direct phone numbers for decision-makers at Ossian City Of STP, plus the full compliance history and discharge data.

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Nearby wastewater treatment plants in Iowa

Calmar City Of STP

Calmar · 5 mi away

0.14 MGD

Castalia City Of STP

Castalia · 6 mi away

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Fort Atkinson City Of STP

Fort Atkinson · 7 mi away

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St Lucas WWTP

St Lucas · 9 mi away

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Spillville City Of STP

Spillville · 9 mi away

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Decorah City Of STP

Decorah · 11 mi away

0.92 MGD

Festina-Winneshiek County-STP

Decorah · 11 mi away

0.0067 MGD

Postville City Of STP

Postville · 12 mi away

0.31 MGD

Ossian City Of STP: frequently asked questions

Sources and methodology

Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.

Data refreshed October 26, 2026; facility record last updated March 28, 2025.

Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Ozonation · Activated sludge · all terms

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