The odors that come from a wastewater treatment plant aren’t always pleasant. People who live near the plant may start to wonder just how safe it is to have windows open and be breathing those smells all day. What about the fecal matter that’s found in wastewater? Can any of it fall on the surfaces in their home and lead to health issues? When they’re not sure, they come to your plant managers or the district with concerns.
As the plant manager, you’re not sure how to answer. Do they have valid concerns? You can’t dismiss them, so what do you tell them? Here’s what you need to know about the safety of living near a wastewater treatment plant.
What Studies of Air Quality Find?
So, what are the risks? Is your plant releasing bacteria into the atmosphere that makes your community members sick? It’s not likely.
A study was performed in Greece to find out exactly how much pollution impacted residents who lived near a wastewater treatment plant in Patras. The plant’s basic set-up included screens, grit chambers, outdoor primary and secondary settling tanks, outdoor chlorination, and indoor sludge treatment.
The study looked at a 1,640-foot radius and only focused on people who lived in their homes for at least eight hours per day. Once a week for an entire month, samples of the air were taken in six different neighborhoods. The samples were collected in the morning, afternoon, and evening to account for different flow rates coming into the treatment plant. Researchers also collected notes on the temperature, weather conditions, and humidity levels.
Once samples were collected, they were delivered to the processing lab within two hours. Bacteria were treated and allowed to incubate for the next 24 hours. At that point, an expert analyst looked at each to count any colonies that had formed. In bacterial colonies that did form, around 36% were Strep, 29% were Staph, 21% were not identified, 9% were E. coli, and 5% were Enterococcus. Salmonella was not found. All had less than 800 colony-forming units per cubic meter each day.
While the researchers identified airborne contaminants, there were very low concentrations. The two sampling stations that had the highest concentrations were right near the wastewater treatment plant.
This sounds concerning but consider this. An NSF International Public Health and Safety Organization study of germs in the household found Coliform on 3 out of 4 kitchen sponges or dish rags. Coliform was found on almost half of the kitchen sinks in the study. The bacteria were also found on 3 out of 10 counters and 2 out of 10 cutting boards. There were more Coliform colonies on toothbrush holders than there were on bathroom faucet handles.
Bacteria thrive in warm, moist environments. It’s why more bacteria are found in sponges than on a computer keyboard. If a homeowner isn’t constantly sanitizing their sponges, towels, sinks, and bathmats, Coliform is likely already in their home. Bathrooms and kitchens are the most common areas to find bacteria, but it’s not limited to those areas.
Coliform bacteria are not the only bacteria in the home. Pet toys and pet bowls turned out to be a significant source of Staph. Staph was also commonly found on game controllers and remotes. The five germiest items in a household were the kitchen sponge or dishrag, the kitchen sink, the toothbrush holder, pet bowls, and the coffeemaker’s water reservoir.
Plant Upgrades Help Lower Odors and Airborne Contaminants
Go back to the days of Hippocrates for some of the earliest evidence that airborne pollutants can impact health. As early as 460 B.C., Hippocrates notes that men were becoming sick after being outside and breathing smelly air. The smells were likely from composting materials in swamps and ponds during the warmer summer months. That helped spark changes leading to more sanitary ways to dispose of those killed in wars or human waste in camps and communities.
Fast forward dozens of centuries later. Today’s wastewater treatment plants do everything possible to lower the risk of airborne contaminants. Through the use of tank covers, it can help stop hydrogen sulfide and methane from being released into the air. Covers also help keep debris like leaves, dust, and tree pollen from getting into wastewater basins. Are these covers enough, or do additional steps help reduce the risk of airborne contaminants?
You do need to start by determining where the odors come from. Check everything from the pump station to the settling tanks. It could be one specific area or several of them. Your findings help you determine the best solution. If you use open screw pumps to move wastewater from one location to the next, odors will escape. Switching to closed screw pumps stops the smells from releasing.
Some wastewater plant upgrades can help lower the odors of your plant. One of the first to consider is covers. A gas-tight cover stops hydrogen sulfide from entering the environment. Whether you choose aluminum, steel, or fiberglass, you can get retractable covers, floating covers, or flexible geomembranes. How do you choose the best one? Consider these factors.
- Is it airtight?
- Can it stand up to environmental factors like temperature changes and weather conditions?
- Will it make your employees’ jobs more difficult?
- Does it impact your plant’s safety?
- How easy is it to get a custom cover that matches your plant’s needs?
These covers become a money-saving step to take as it also keeps algae from growing, and it adds thermal protection in the winter. When you add a gas collection cover, the methane produced during wastewater treatment is captured and can be used to heat and power your plant. That lowers operating costs.
Deodorizing misting systems throughout the plant help neutralize the smells. Another option is to start adding chemicals that react with the compounds that cause the odors. Adding an air purifying system that captures the air, filters it through biofilters or carbon filters is also helpful. Once the air is filtered, it can go out into the atmosphere without leading to unpleasant odors.
While each of these methods will help, a cover is highly effective. You may find you need multiple plans to combat odors. Don’t get discouraged. Weather extremes are changing average annual temperatures and conditions. Smells may be worse in high humidity. A windy day may make the odors travel farther than usual. If you’re having a hard time figuring it out, don’t forget wastewater equipment specialists have the answers you need.
Keeping the people in your wastewater district is one of the best ways to ensure they’re happy. If water costs are low, they’re less likely to complain. Covers are the most cost-effective solution in a wastewater treatment plant. If you don’t have covers on your tanks, you should consider them. Talk to Lakeside Equipment about equipment upgrades that help reduce odors and lower your operating costs.
Also, keep them informed. If there are more odors in the summer, explain why and assure them it’s temporary. Be honest and reassure them you’re doing everything possible to lower the smells that are emitted. Offer free tours, show why the odors occur, and listen for feedback. If you’re still not sure how to help reduce the odors that bother your neighbors, Lakeside Equipment’s specialists help you find the right solutions to incorporate in your wastewater plant design.