Control Hydrogen Sulfide at Lift Stations
Lift stations are among the most concentrated sources of hydrogen sulfide in a sewage collection system. Wastewater sits in the wet well, retention time builds, and anaerobic bacteria go to work on the organic material long before that flow ever reaches a treatment plant. Every time a pump cycles or wastewater enters the well, dissolved sulfides are agitated and released into the air. Because lift stations are frequently located near residential neighborhoods, the odor doesn’t remain contained within the collection system. It becomes a direct source of community complaints. At the same time, the hydrogen sulfide that isn’t escaping into the air is dissolving into the wastewater itself, quietly corroding the concrete wet well, metal fittings, and force main with every hour of exposure.
Lift stations also present a real safety concern. Airborne hydrogen sulfide concentrations inside a wet well or valve vault can climb into ranges that are immediately dangerous to anyone who has to enter for maintenance or inspection, making treatment at the source a matter of worker safety, not just odor control.
Treating a lift station with Ultra-S3® doesn’t require any infrastructure modification. Metering equipment is set up directly at the lift station grounds, injecting Ultra-S3 and an oxidant such as hydrogen peroxide into the incoming wastewater line. From there, the same hydroxyl radical chemistry used throughout the Ultra-S3 process destroys sulfides before they have a chance to off-gas or corrode downstream infrastructure, with dosing calculated based on the specific sulfide load and flow at each station.
Proven Results at Lift Station 23, Melbourne, Florida
A survey of Lift Station 23, part of the north-end sewage collection system in Melbourne, Florida, found conditions that posed both a serious odor problem and a serious safety concern. Over two weeks of pretreatment testing, airborne hydrogen sulfide at the station ranged from 500 ppm to over 1,000 ppm, while total sulfides in the wastewater column averaged 9-12 mg/L across two 24-hour sampling events. Flows into the station ranged from 1.5 to 2.1 million gallons per day.
Based on that data, a dosage of Ultra-S3® and hydrogen peroxide was calculated to reduce sulfide levels to within Melbourne’s treatment goals: less than 1.5 ppm in the water column and less than 200 ppm in the air. The results:
- A calculated dosage of approximately 56 gallons per day met the target reduction, with actual field treatment settling at approximately 60 gallons per day
- Airborne hydrogen sulfide, which had spiked as high as 1,000 ppm before treatment, was brought down to a stable range well under 200 ppm, with most readings far lower
- Wastewater sulfide levels, which had ranged as high as 18 to 20 mg/L at peak times of day, dropped to consistently under 2 mg/L across the full 24-hour cycle after treatment
- No grease buildup was observed at the station during treatment
- Treatment was accomplished entirely from the lift station grounds, with no infrastructure modifications required
Based on similar sulfide levels found at two additional stations in the system, the study projected that approximately 120 gallons per day of combined dosing would treat all three stations, with the likelihood of lower dosages during colder months as biological activity slows.
The study’s broader conclusion pointed beyond odor control. It noted that Melbourne’s collection and treatment system was likely experiencing significant, ongoing infrastructure decay from sulfide-related corrosion, destroying concrete and metal throughout the system, including at the receiving wastewater treatment plant, and that a full accounting of those costs would likely reveal substantial annual losses directly tied to untreated hydrogen sulfide.