Texas Wastewater Pretreatment Permits: What Industrial Facilities Discharging to a POTW Must Know

Why doesn't a sewer connection settle the question?

Because the plant has its own permit to protect. A publicly owned treatment works (POTW) discharges under its own TPDES permit. If your wastewater upsets its biology, passes through to the creek, or contaminates its sludge, the city is the one in violation.

The federal pretreatment rule at 40 CFR Part 403 exists to stop that. It calls the harms "interference" and "pass through," and it gives the city the tools to control industrial users. Texas adopts Part 403 by reference at 30 TAC §305.542.

Does every Texas city run a pretreatment program?

No. Under 40 CFR §403.8(a), a POTW with a total design flow above 5 million gallons per day that receives regulated industrial wastewater must have a program. TCEQ can require one at a smaller plant too. As TCEQ's approved pretreatment program page says, the city's own wastewater permit establishes whether it must run one.

TCEQ approves the city programs, audits each about once every five years, and inspects between audits. Where a city has no approved program, the federal definition makes TCEQ, as the approval authority, the control authority for industrial users. Our post on pretreatment program delegation covers that split.

A city without a program still has a sewer use ordinance and can refuse or restrict a connection that would harm its plant.

Which limits will apply to my wastewater?

Three layers, and the strictest controls.

1. General and specific prohibitions. 40 CFR §403.5 applies to every industrial user, program or not.
2. Categorical standards. If your industry has a federal pretreatment standard, such as metal finishing or pharmaceutical manufacturing, it applies wherever you locate.
3. Local limits. Cities with programs must develop and enforce specific limits that protect their plant. These vary by city and change when the plant's permit changes.

The specific prohibitions are worth knowing by heart. They bar pollutants that create a fire or explosion hazard, including a closed-cup flashpoint below 140 degrees Fahrenheit, and discharges with pH lower than 5.0 unless the plant is designed for them.

They also bar solids that obstruct flow, any pollutant at a rate or strength that causes interference, heat that inhibits biological activity or pushes the temperature at the treatment plant above 104 degrees Fahrenheit unless an alternate limit is approved, petroleum and mineral oils that cause interference or pass through, toxic gases, and trucked waste except where the city designates.

What does the city usually look at first?

Strength, grease, metals, pH, temperature and timing. High-strength organic waste from food and beverage plants loads the plant's aeration far beyond what the flow suggests. Fats, oils and grease clog the collection system, which is why grease interceptors are a standard local requirement.

Metals from plating and finishing pass through biological treatment and end up in effluent and sludge. Sludge quality limits for land application are set under 40 CFR Part 503, so cities watch metals closely.

Acid or caustic streams and hot discharges damage pipe and upset treatment. Batch discharges at shift change can create peaks even when the daily average looks fine. Each of these can lead to a pretreatment requirement such as neutralization, cooling or equalization.

What does the permitting process look like?

A survey, a classification, then a permit if you are significant. Most cities start with an industrial user survey or application describing your processes, flows, chemicals and wastewater quality. The city then decides your category.

A significant industrial user gets an individual permit, for no more than five years, with limits, a sampling schedule, reports and any required pretreatment. The four tests that make a facility significant are in our post on SIU designation. A smaller user may connect under the ordinance alone, with local requirements such as a grease interceptor.

Parameters follow the industry. A food plant's permit usually addresses BOD, TSS, FOG, pH and flow. A metals user's permit addresses metals, pH and flow.

What should I check before signing a lease or buying land?

Whether the plant will take your wastewater, and what it will cost you to meet its terms. Before you commit, confirm:

1. Whether the city has an approved pretreatment program, and who the control authority is
2. Whether your process falls under a categorical standard
3. The city's current local limits and surcharge rules for strength
4. Whether the plant has capacity for your flow and organic load
5. What pretreatment equipment, sampling point and space the permit is likely to require
6. Whether your likely flow or load would make you a significant industrial user

The answers belong in the pro forma. Pretreatment equipment and ongoing sampling are real capital and operating costs.

What if the city cannot accept the wastewater?

Then you are looking at private treatment. The options are a private plant with a TPDES discharge permit, a Texas Land Application Permit, or, for a project with a real reuse demand, an authorization under 30 TAC Chapter 210. Each has its own rules, and a mixed industrial and domestic stream changes which Chapter 210 rules apply, so confirm the path with TCEQ early. We have taken a food distribution project in Fort Bend County down the private treatment path.

Our post on industrial TPDES vs. TLAP compares the two most common private paths.

This post explains the federal and Texas framework as general education. The receiving city's ordinance, local limits and permit decide your case, so confirm the requirements with its pretreatment staff.

Frequently asked questions

Do the federal prohibitions apply if the city has no pretreatment program?

Yes. The general and specific prohibitions in §403.5 apply to every industrial user discharging to a POTW, whether or not the city runs an approved program.

Is pH 5.0 the limit I have to meet?

pH 5.0 is the federal floor. Most cities set a narrower local range, with an upper limit too. Your permit or ordinance sets the number you design to.

What happens if we discharge before meeting the city's requirements?

The city can issue a notice of violation, order the discharge stopped and, under its ordinance, disconnect service. Its enforcement response plan sets the steps.

We're a food distribution developer looking at a site in a DFW suburb. The tenant will do some food processing. What should we ask the city before we sign?

Ask whether it has an approved pretreatment program, what its local limits and strength surcharges are, whether the plant has capacity for the tenant's flow and organic load, and what grease, pH and sampling equipment it would require. Get the answers in writing before the lease is final.

Can the city change our limits after we are permitted?

Yes. Local limits can change, often when the plant's own permit changes. Ask the city for notice of proposed changes, and keep margin in your pretreatment design so a tighter limit does not force a rebuild.

Related resources

• Slug Discharge Control Plans: What Texas Industrial Users Must Have on File
• FOG Pretreatment Programs for Texas Restaurants and Food Service Facilities
• Pretreatment Permit Appeals Process When a Texas POTW Denies a Discharge Request
• How to Evaluate Wastewater Utility Options Before You Close on Land (Connect, Build, or Wait)

Not sure the city will accept your facility's wastewater?

We characterize the wastewater, check it against the city's program before you commit, and design either the pretreatment or the private treatment the site needs.

We specialize in:

• Industrial wastewater characterization
• POTW pretreatment requirement reviews before lease or purchase
• Industrial user permit applications and city coordination
• Pretreatment design for FOG, pH, metals and high-strength waste
• Private wastewater treatment feasibility
• TPDES, TLAP and Chapter 210 applications

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com