What Is a "Categorical Industrial User"?
A categorical industrial user (CIU) is a facility that meets these conditions:
The facility discharges process wastewater to a publicly owned treatment works (POTWs)
In the EPA Pretreatment Categories and Standards, the categorical activity is assigned pretreatment limitations, reporting requirements, or both.
If you are a CIU, then you must comply with the categorical pretreatment standards specified in the federal regulations and any local limits established by the POTW that receives your wastewater discharges.
For assistance to determine whether you are a CIU, please submit a "Request for a Categorical Determination" to the TCEQ. The application requirements are listed in 40 CFR §403.6.
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