How much wastewater does Walnut City Of STP treat?

Walnut City Of STP treats an average of 0.17 MGD and is permitted for a design flow of 0.39 MGD.

What treatment technology does Walnut City Of STP use?

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

What is the NPDES permit for Walnut City Of STP?

The facility discharges under NPDES permit IA0042986, currently administratively continued, expiring April 2006.

Is Walnut City Of STP in compliance?

Discharge monitoring reports show 42 violations at Walnut City Of STP in the last three years, 42 of them effluent limit exceedances. The full history is available in Klarifi.

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

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

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Walnut City Of STP

Walnut, IA 51577 · Pottawattamie County · Publicly Owned Treatment Works

Average flow: 0.17 MGD

Design flow: 0.39 MGD

NPDES permit: IA0042986; Administratively continued

Permit expires: April 2006

Population served: 747; CWNS 2022

Walnut City Of STP is a publicly owned wastewater treatment works in Walnut, Pottawattamie County, Iowa treating an average of 0.17 million gallons per day against a permitted design capacity of 0.39 MGD, serving about 747 residents. It discharges under NPDES permit IA0042986 (administratively continued), which expires in April 2006, with 42 recorded violations in the last three years.

Treatment technology

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

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

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Compliance snapshot (last 3 years)

Total violations: 42

Effluent violations: 42

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

Key contacts

1 verified contact for Walnut 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 Walnut City Of STP, plus the full compliance history and discharge data.

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Nearby wastewater treatment plants in Iowa

Avoca City Of STP

Avoca · 7 mi away

0.13 MGD

Hancock City Of STP

Hancock · 10 mi away

—

Atlantic City Of STP

Atlantic · 11 mi away

0.69 MGD

Elk Horn City Of STP

Elk Horn · 11 mi away

0.04 MGD

Harlan City Of STP

Harlan · 12 mi away

0.62 MGD

Kimballton City Of STP

Kimballton · 12 mi away

0.04 MGD

Shelby City Of STP

Shelby · 12 mi away

—

Oakland City Of STP

Oakland · 16 mi away

0.08 MGD

Walnut 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 August 3, 2026.

Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Significant industrial user · WWTP · all terms

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