When people think of wastewater odor, the knee-jerk reaction is often, “Well, it must be the poop.” And to be fair, that assumption isn’t completely off base. But if you ask Lewis Titus, founder of Titus Wastewater Solutions and trusted advisor to municipalities across the country, it is more than just an oversimplification. It is a costly misconception that can derail entire odor control strategies.

“There are a lot of things in wastewater that stink,” Titus explains. “And it’s not always what you think it is.”

Misunderstanding the true sources of odor is one of the biggest reasons traditional wastewater odor control efforts fall short. Cities and businesses spend thousands on chemical treatments and mechanical fixes, only to find the problem still lingering. In some cases, it gets even worse. Why does this happen? Because most systems are designed to treat the symptoms rather than the actual sources.

This blog is part of a broader series exploring common misconceptions and smarter approaches to wastewater odor control. Today, we are taking a closer look at where those foul smells really come from. It is not just about solids or sewage. From industrial discharges to biological buildup inside force mains, the worst offenders are often the ones no one sees coming.

What’s Really Causing the Stink?

While fecal matter does contribute to wastewater odor, many of the most potent and persistent smells come from less obvious sources. These hidden contributors often fly under the radar, yet they can completely overwhelm a system’s odor control efforts if left unaddressed.

Ammonia is a prime example. It enters the system primarily through urine and can be present in surprisingly high concentrations. Its strong, sharp scent is hard to miss, and when it combines with other compounds, it can make lift stations and headworks unbearable for operators and nearby communities alike.

Industrial discharge can be even more extreme. One of the worst odor cases Titus ever encountered came from a jewelry manufacturing plant. The problem had nothing to do with sewage. Instead, the culprit was a chemical-heavy effluent that overwhelmed the system and triggered a hydrogen sulfide sensor at over 1,000 parts per million. These kinds of industrial inputs are often overlooked in wastewater odor control plans, but they can drastically increase both the complexity and severity of odor issues.

Laundry detergents and cleaning agents may smell pleasant in your home, but once they reach a collection system, they become part of a volatile chemical mixture. The surfactants and synthetic fragrances can interact with other substances in unpredictable ways, contributing to distinct and lingering odors at various points in the system.

Biofilm buildup in force mains is another sneaky offender. Inside these pressurized pipelines, bacteria accumulate and form layers that produce dissolved sulfides. Once these sulfides are exposed to air, typically at discharge points, they rapidly convert into hydrogen sulfide (H₂S) gas. This gas is a major cause of system-wide odor complaints and has been addressed effectively through non-chemical wastewater odor control strategies like ozone in real-world applications 

Rag and grease accumulation rounds out the list. As debris, fats, oils, and grease settle in wet wells and other low-flow areas, they begin to decay. Over time, they form dense mats and sludge that slowly break down, releasing a cocktail of odorous gases that are difficult to mask and even harder to eliminate.

As Titus points out, “The moment you smell H₂S, you’re detecting levels as low as 2 parts per million. But the scary part? At higher levels, it actually destroys your ability to smell it.”

In other words, if you are relying on your nose to manage odors, you are already behind. Hydrogen sulfide and other gases can reach harmful concentrations long before a complaint ever hits your desk. That is why effective wastewater odor control cannot be based on assumptions or reactions. It requires a full understanding of the system, the sources, and how they interact over time. Without that foundation, even the most aggressive treatment plan is likely to fail.

Gravity vs. Force Main Systems: It Matters

One of the most important, and most overlooked, factors in wastewater odor control is the type of system in place. Whether the system is gravity-fed or pressure-driven changes everything about how odor is created and released.

• Gravity-fed systems allow wastewater to move through open-air infrastructure. Because they are vented to the atmosphere, hydrogen sulfide levels tend to stay low. But even in these setups, small releases of gas can trigger complaints, especially in areas where lift stations or manholes are located near homes or businesses. These systems are often assumed to be low-risk, but they are not immune to odor problems.
  
• Force mains move wastewater under pressure through fully enclosed pipes. These systems do allow for any exposure to oxygen, and the bacteria quickly consume any available dissolved oxygen in the effluent. Anaerobic conditions cause biofilm to develop along the pipe walls, where the bacteria generate dissolved sulfides. When the wastewater is finally released, especially into open air, those sulfides convert rapidly into hydrogen sulfide gas, resulting in a strong and sudden odor.

Titus warns that improper design choices, such as discharging into the atmosphere instead of underwater, can significantly worsen the odor problems. Cascades, as we refer to them, immediately expose dissolved sulfides to the atmosphere where they convert to H2S gas. If possible; influent should enter the wet well under water to prevent this. 

A strong wastewater odor control plan must be based on how the system actually behaves. If you treat a force main like a gravity line or assume all odors come from the same place, you are not solving the problem. You are just managing the fallout.

Why Chemicals Aren’t Always the Answer

For decades, municipalities have relied on chemical treatments as their primary method of wastewater odor control. When odors spike or complaints increase, the typical response is to dose the system with neutralizing agents. While this can offer temporary relief, it often fails to address the real causes of odor and introduces new challenges in the process.

Traditionally, that quick fix approach has come with a different set of problems, some of which are just as persistent as the odors themselves:

• High recurring costs: Tanks, pumps, dosing equipment, and the chemicals themselves represent a significant and ongoing financial burden. What starts as a short-term fix can quickly become a permanent line item in the operations budget.
  
• Decreasing effectiveness over time: Microbial communities within wastewater systems adapt. The bacteria that once responded to a particular treatment can become resistant, requiring larger doses or entirely new chemicals just to achieve the same effect.
  
• Unintended side effects: Some chemical additives react with other compounds in the system, producing new odor compounds or contributing to corrosion and compliance issues. In some cases, the treatment causes more problems than it solves.

“And every year, your costs go up,” Titus notes. “Because the bugs figure it out. They adapt. So you’re just masking the problem, not solving it.”

These limitations highlight a critical flaw in many odor control strategies: they are reactive instead of proactive. Instead of targeting the underlying causes of odor, such as system design, flow dynamics, and biological activity, chemical programs often focus only on suppressing the symptoms. That approach may calm complaints in the short term, but it rarely leads to lasting results. As these limitations become harder to ignore, more utilities are moving away from symptom-masking chemicals and turning to system-based wastewater odor control strategies focused on long-term results.

It’s Time to Treat the Cause, Not Just the Symptom

The key to effective wastewater odor control is understanding the real sources of the problem. Without that foundation, any solution, chemical or otherwise, is just a temporary fix.

Titus Wastewater Solutions helps municipalities break out of that cycle. With decades of hands-on field experience, Titus and his team have developed a proven, non-chemical approach that treats odor at its source and creates lasting results. It is not about masking the symptoms. It is about solving the problem.

One of the most powerful tools in that process is ozone, a naturally occurring compound with incredible odor-fighting potential. We will explore how and why it works in our next blog:

“What Lightning and Lift Stations Have in Common: Ozone Wastewater Treatment in Action”

Ozone is nature’s deodorant. A bolt of lightning will create about 300 lbs. of ozone, and is what makes the air smell so fresh after a storm. It is a very powerful oxidizer. We recreate this with a corona discharge ozone generator that is very small, simple, and economically creates ozone from the atmosphere. This is mixed with a large volume of air and delivered to a specialized “air lift” diffuser head that is installed in the wet well, and delivers measured amounts of ozone into the wastewater stream where it attacks dissolved sulfides, and other odorous compounds as well as FOG molecules. 

The system will not only eliminate most odors, but will reduce your pump station maintenance costs significantly by eliminating most pump outs, and eliminating “MOP Heads,” the balls of rags that plug up your pumps. 

In the meantime, if your current odor control plan feels like a money pit with no end in sight, now is the time to start asking different questions. Contact us to learn how a smarter, source-focused strategy can help you finally get ahead of the problem.