Odors emanating from two pumping stations in Naperville, Illinois, have been eliminated through the use of hydroxyl radical misting units.
As a result, the phone does not ring as much as before in the city of Naperville Water Service Center. And that is a good thing.
In the past, neighbors called to complain about hydrogen sulfide odors at the North and Northwest pumping stations, even though both were equipped with carbon scrubbing systems.
Now, both stations are using hydroxyl radical misting units from Vapex Environmental Technologies, which eliminate hydrogen sulfide through a combination of air, water and ozone. The mist is directed into the odorous areas through a patented three-fluid nozzle.
Hydrogen Sulfide AKA H2S
As wastewater operators and managers well know, hydrogen sulfide is produced naturally from decaying organic matter. It can be released from sewage sludge and wastewater collection systems. It is poisonous, corrosive and flammable. It can cause a wide range of health effects.
Workers are primarily exposed to hydrogen sulfide by breathing it. The effects depend on how much hydrogen sulfide one breathes and for how long.
Typical background concentrations of H2S are in the 0.01 to 1.5 ppm range. The odor becomes more offensive at 3 to 5 ppm.
Above 30 ppm, H2S odor is often described as sweet or sickeningly sweet. Higher concentrations can lead to marked conjunctivitis and respiratory tract irritation, pulmonary edema, unconsciousness and death (at 1,000 to 2,000 ppm).
At Naperville’s Northwest pumping station, odor complaints averaged 15 annually; at the North station, complaints averaged four per year. H2S concentrations at both stations measured about 150 ppm.
Since the Vapex units went on line, odor complaints have been zero.
With more than 43,000 customers, the Naperville water and wastewater utility is one of the largest in the state and collects and treats approximately 19.7 million gallons per day (mgd) of wastewater at its Springbrook Water Reclamation Center.
The North and Northwest pumping stations—both indoors at covered wet wells—are important components in the city’s 564-mile long sewer system.
The North station measures 28 feet long by 14 feet wide and 33.5 feet deep (13,132 cubic feet of volume). Average flow is 3.2 mgd with a peak of 19.7 mgd. The Northwest station is 18 feet by 16 feet by 48 feet deep (12,384 cubic feet of volume). Average flow is 3.6 mgd with a peak of 12 mgd.
In the past, carbon scrubbers were used to control odors, but the cost and maintenance of each carbon unit were giving the collections staff problems. Maintenance included fan motor shaft alignment, replacement of bearings, carbon replacement at breakthrough and time and equipment associated with carbon change out.
Read more:: Odor Control: Air. Water. Ozone.