When Your Wastewater Numbers Won't Cooperate

You get the lab results back. BOD is four or five times over your permit maximum. Zinc is nearly double. The county sends a Notice of Violation. And now you're in a conversation you weren't ready for.

I've dealt with this situation at a manufacturing facility and it's a grind. But it's manageable if you approach it right.

Figure Out Where It's Coming From

This sounds obvious but most facilities skip this step. They see high BOD numbers and start looking at their wastewater treatment plant. But the WWTP isn't usually the problem. The problem is what you're sending to it.

In one case I worked on, the primary driver of elevated BOD was product washdown from a production line. The team was washing equipment at the end of each run, and all of that high-organic-load water was going straight to the treatment system, which wasn't sized for it. BOD levels were running around 9,000-10,000 mg/L against a permit max that was a fraction of that.

The zinc issue traced back to specific product ingredients. Certain formulations contained zinc compounds, and trace amounts were ending up in the wash water. The chelating agents in the cleaning chemicals (EDTA-based products) were making it worse by keeping the zinc in solution through the treatment process instead of letting it settle out.

Short-Term Fixes

Once you know the sources, there are usually some quick wins:

• First flush capture. The initial washdown has the highest concentration of contaminants. Capture it separately and either dispose of it as waste or treat it before it hits your system.
• Eliminate the chelating agents. If your cleaning chemicals contain EDTA or similar chelants, switch to alternatives. The chelants keep metals in solution and prevent your treatment system from doing its job.
• Dry sweep before wet wash. Get as much product off surfaces as possible before you turn on the water. A broom and a dustpan prevent a lot of BOD from ever reaching the drain.
• pH optimization. For metals like zinc, adjusting pH to the 9.5-10 range can significantly improve precipitation and settling. This is basic chemistry but it gets overlooked.

Long-Term Fix: Upgrading the WWTP

The short-term stuff buys you time and demonstrates good faith to the regulator. But if your facility has outgrown its wastewater treatment system, you're going to need an engineering assessment and a capital plan.

In the situation I'm describing, we brought in a wastewater engineering firm to do a full assessment. They looked at flow rates, loading, treatment capacity, and recommended a path forward that included equalization tanks and enhanced biological treatment. Not cheap — but cheaper than ongoing violations and the risk of an enforcement action.

The key is getting the assessment done and having a credible plan to show the regulatory agency. Regulators aren't unreasonable. They understand that WWTP upgrades take time and money. What they don't tolerate is inaction. If you can show them a timeline, a budget, and evidence that you're implementing interim controls, they'll generally work with you.

Responding to the NOV

When you get a Notice of Violation, respond promptly and honestly. Acknowledge the exceedance. Explain the root cause you've identified. Detail the short-term corrective actions you've already taken. Outline the long-term plan with a timeline.

Don't be defensive. Don't make excuses. And don't promise things you can't deliver. If the WWTP upgrade is going to take 12 months, say 12 months. If you're still waiting on engineering results to put a number on it, say that and give a date when you'll have the number.

The goal is to show that you take it seriously, you understand the problem, and you're moving. That usually gets you the time you need.