Eliminate Hydrogen Sulfide at Wastewater Treatment Plants
Hydrogen sulfide (H2S) is one of the most persistent problems facing wastewater treatment plants. It forms wherever wastewater sits long enough for anaerobic bacteria to break down organic material in force mains, lift stations, and headworks, and it doesn’t stay put. As septic wastewater reaches the plant, H2S off-gases into the air, creating the rotten-egg odor that drives community complaints, and dissolves back into the water, where it silently corrodes concrete, steel, and every piece of infrastructure it touches. It’s also a genuine safety hazard: H2S alarms in headworks buildings exist because airborne concentrations can quickly become dangerous to plant staff.
Ultra-S3® was engineered to solve this problem at the source. Paired with a low-concentration oxidant such as hydrogen peroxide, Ultra-S3 generates hydroxyl radicals, among the most powerful oxidizing agents available, that attack and destroy H2S and other reduced sulfur compounds on contact. The reaction is fast, typically requiring only a few minutes of contact time, and it converts sulfides into stable, non-hazardous end products rather than simply masking odor or shifting the problem downstream.
Because the reaction is targeted, Ultra-S3 doesn’t act like a blunt-force chemical. It won’t strip out the beneficial biology that treatment plants rely on for downstream processes, and it’s non-hazardous under TSCA. It can be metered directly into force mains, wet wells, or headworks influent lines, with dosing adjusted proportionally to flow, meaning it scales from a single lift station to a full regional treatment plant handling tens of millions of gallons a day.
The result for plant operators: fewer odor complaints, longer infrastructure life, safer working conditions, and a treatment process that doesn’t fight the biology already doing the rest of the job.
Proven Results at Full-Scale Wastewater Treatment Plants
Northern California Wastewater Treatment Plant, 30 MGD
At the Northern California Wastewater Treatment Plant (NCWWTP), which treats 30 million gallons per day, hydrogen sulfide in the influent air had become severe enough to routinely trigger safety alarms in the headworks maintenance building, with atmospheric readings averaging 123 ppm overnight and spiking as high as 250 ppm.
Ultra-S3 and hydrogen peroxide were metered into the wastewater line upstream of the bar screens, providing less than three minutes of contact time before treatment was complete. The results were dramatic:
- Airborne hydrogen sulfide at the headworks dropped from a range of 102–250 ppm down to less than 10 ppm
- Dissolved hydrogen sulfide in the wastewater fell from an average of 7.7 ppm to just 2–3 ppm at the bar screens
- The estimated mass reduction of hydrogen sulfide totaled approximately 1,200 pounds
- Safety alarms, which had sounded frequently before treatment, stopped sounding entirely during the study
All of this was achieved with most of the reaction complete within three minutes of contact time, a level of speed that let the plant treat sulfide at the point of entry rather than managing it after the fact.
York River Wastewater Treatment Plant, 12–14 MGD
A full-scale pilot at the York River Wastewater Treatment Plant put Ultra-S3 to the test under conditions that exceeded its original design criteria. Incoming total sulfide loading, which had been expected to run around 1,000 lbs/day, instead regularly topped 2,500 lbs/day due to storm-driven flow increases, more than double the anticipated load.
Even under these elevated conditions, the system performed:
- Sulfide reductions of 84% to over 94% were recorded across multiple test periods
- During periods when dosing capacity matched incoming load, sulfide entering the plant’s scrubber system was reduced to zero
- Average mass reduction attributable to Ultra-S3 treatment reached 2,238 pounds of sulfide per day
- The mass ratio required was confirmed at no more than 1.5 parts hydrogen peroxide to 1.0 part sulfide
Plant staff also observed a clear visual shift in the wastewater itself: influent that had been consistently dark, almost black, turned milky in color from the bar screens through the primary clarifiers, a visible indicator of a fundamental change in the oxidation-reduction potential of the water, and a strong sign of reduced corrosivity throughout the plant’s infrastructure.
The study’s conclusion was direct: with adequately sized metering equipment, Ultra-S3 was capable of reducing airborne hydrogen sulfide entering the scrubber system to negligible or non-detectable levels, even at more than twice the plant’s original design load.