The discharge & the receiving water
Dilution at the design low flows, and the burden the receiving water already carries.
A real impact study screens the project's discharge against the assimilative capacity of the receiving stream — how much pollutant that stream can take before it breaches a criterion — at the stream's cited design low flows. The design flow matches the criterion type: chronic aquatic-life dilution at the 7Q10, and acute dilution at the 1Q10, which is the sharper single-day design low flow. It also sets that discharge beside what the county's TRI reporters already release. These are screening bands. They are not a permit determination.
The dilution screen · baseline
| Discharge → receiving water | Design 7Q10 | Discharge | Chronic | Credited | Acute (1Q10) | Evidence |
|---|---|---|---|---|---|---|
| Shawnee II WWTP→ Ottawa River | 0 cfsOhio EPA NPDES fact sheet 2IG00001 (Lima Refining Co.), Stream Flows table — Ottawa River at Lima, USGS gage 04187100, 1989-2021 | 5 cfs | 0.04:1 · violation | 6.21:1 · tight | 0.00:1 · violation | [verified] |
| American Bath WWTP→ Pike Run | 0 cfsOhio EPA NPDES fact sheet 2PH00007 (American Bath WWTP), Stream Flows table — USGS Gauge 04186500 adjusted for drainage area | 2 cfs | 0.01:1 · violation | — | 0.01:1 · violation | [verified] |
| American II WWTP→ Dug Run | 1 cfsOhio EPA NPDES fact sheet 2PH00006 (American II WWTP), Stream Flows table — USGS Station 04187500 | 2 cfs | 0.42:1 · violation | — | 0.32:1 · violation | [verified] |
| Lima WWTP→ Ottawa River | 0 cfsOhio EPA NPDES fact sheet 2IG00001 (Lima Refining Co.), Stream Flows table — Ottawa River at Lima, USGS gage 04187100, 1989-2021 | 29 cfs | 0.01:1 · violation | 0.17:1 · violation | 0.00:1 · violation | [verified] |
4 of 4 receiving reaches fail a dilution band at design low flow. The effluent-credited ratio counts the permitted effluent already in the reach (WS-15); a cited 1Q10 of 0 cfs is a stream that runs dry at design low flow — no acute capacity at all.
What the county's TRI reporters already release
| Facility | City | RSEI score |
|---|---|---|
| INEOS NITRILES USA LLC | LIMA | 39,726,351.2 |
| WHEMCO-OHIO FOUNDRY INC | LIMA | 13,876,817.4 |
| LIMA REFINING CO | LIMA | 3,300,620.9 |
| U.S. ARMY JSMC GENERAL DYNAMICS LAND SYSTEMS | LIMA | 3,054,683.5 |
| PCS NITROGEN OHIO L.P. | LIMA | 1,996,618 |
Any new discharge lands on top of this baseline — the point of reading the two halves together. The full ranked inventory and its reading caveats are in the RSEI annex.
A dilution ratio below 1.0 looks like an error. Here it is the finding.
Dilution compares the water available to receive a discharge against the discharge itself. A ratio of 10:1 means ten parts river to one part effluent. Three of the four rows above sit at or below 0.04:1, and the Lima and American Bath plants both round to 0.01:1. At the design low flow, those streams carry far less water than the pipes discharging into them. Only Dug Run, at 0.42:1, is even within a factor of three of its own discharge.
That is not a modeling artifact. The streams around Lima are small, and in a drought week they run mostly on what the treatment plants put into them. The Ottawa leaving Lima is overwhelmingly treated effluent before this campus adds anything. A new discharge into water like that has no clean water to mix with.
Read every flag in the table as a screening result. It says a permit writer would have to resolve the question. It does not say a permit has been violated, because no permit determination is on this record to violate.
What the county already releases
The corridor was not empty before the campus arrived. EPA’s Risk-Screening Environmental Indicatorsref rank Allen County’s toxic releases, and five Lima facilities carry the highest scores: INEOS Nitriles, the WHEMCO-Ohio foundry, the Lima refinery, the Army’s Joint Systems Manufacturing Center, and PCS Nitrogen.
Read that ranking for what it is. The score is a modeled, population-weighted comparative index, and it counts releases to air and land as well as to water. It does not say what the Ottawa carries. It says the campus arrives in a county with a long industrial release record, not onto a blank slate.
What this screen still cannot do
The check against the municipal treatment plant is hydraulic only. It compares flows. It does not yet test any single pollutant against that pollutant’s own assimilative capacity, because no per-parameter limits for this discharge are on the record. Ohio EPA’s indirect-discharge permit for the campus, 2DP00130rec , went to public notice on 2026-07-01 with a comment period that closed on 2026-07-31. Its terms are what would turn this hydraulic screen into a chemical one.
The record behind this chapter
What this chapter stands on: the records it reads, the inputs its modeled figures rest
on, and the reference data behind its baselines — the same pages the record screens
serve, not a second copy. A figure the record does not support stays [open] and links nothing.
- Permits22 records
- Enforcement36 records
- Maumee NPDES inventory (EPA ECHO)Reference dataset
- RSEI toxic-release inventory (EPA)Reference dataset