CASE STUDY / MUNICIPAL

Lift Station H2S: From an Iron Scavenger to Prevention at the Source

Hydrogen sulfide (H2S) can be handled after it forms, or its formation can be prevented in the first place. This case looks at a south central Texas lift station that had been running an iron compound to knock H2S down, then switched to DRP Accelerator, dosed continuously at the lift station itself. Read together, the records show what changes when the approach shifts from capturing the gas to preventing it.

The iron compound reacted with the gas after it formed. The accelerator stopped it from forming.

Hydrogen sulfide (H2S) forms in a sewer or lift station when bacteria run out of dissolved oxygen and take oxygen from sulfate instead, leaving behind sulfide that becomes H2S gas.
An iron compound reacts with hydrogen sulfide after bacteria have already produced it, which is a form of scavenging rather than prevention.
DRP Accelerator is an inorganic compound that carries usable oxygen to bacteria already living in the wastewater, with no bacteria or enzymes added.
When bacteria have usable oxygen available, they draw on that oxygen first instead of stripping it from sulfate, so the sulfide that becomes hydrogen sulfide is not formed.
Dosing as far upstream as possible, at a lift station's wet well rather than only at a treatment plant, gives bacteria access to oxygen before the wastewater spends hours in a force main, the low-oxygen stretch of pipe where hydrogen sulfide typically builds up.
A dosing point that depends on a working injection pump can go offline if that pump fails, interrupting treatment until it is repaired.

Published September 9, 2026

The system

This case comes from a lift station in south central Texas that had been dosing an iron compound to control hydrogen sulfide (H2S) in the wastewater collection system before DRP Accelerator replaced it. The study document that records these readings does not print the year the study took place, and it does not name the station. Waste Water Innovations is confirming the station’s written permission before naming it on this page. The document does not give the station’s flow, pump configuration, or the size of the service area behind it.

The problem

Before the switch, the lift station relied on an iron compound to bring hydrogen sulfide down after bacteria had already produced it. Untreated baseline levels at the station typically ran around 210 parts per million (ppm). At a dose of 68 ppm, the iron compound brought H2S down to 15 ppm at its best, and usually left it above 20 ppm, the ceiling the Occupational Safety and Health Administration (OSHA) sets for safe exposure over an eight hour work day. Readings were inconsistent. Even with the iron compound running, H2S often climbed back above 100 ppm. The pattern the study document describes is scavenging: the iron compound reacts with hydrogen sulfide once bacteria have made it, rather than stopping the bacteria from making it in the first place.

Date range	Iron compound dose	H2S reading
January 26 to February 9	68 ppm	Baseline typically around 210 ppm, brought down to 15 ppm at best, usually above 20 ppm, often back above 100 ppm

The study document includes a chart of daily H2S readings plotted against the iron compound dose for this date range. The individual day by day values in that chart are not legible in the source document, so this case study reports only the summary figures above.

What we did

We replaced the iron compound with DRP Accelerator, injected continuously at the lift station at a dose of 14 to 20 ppm. We add no bacteria, no enzymes and no chemical additives. The accelerator carries usable oxygen to the bacteria already in the wastewater, and with that oxygen available they stop taking it from sulfate, so the sulfide that becomes H2S is not formed. Dosing began on July 11, as far upstream in the collection system as the site allowed. Not long after the first day, an injection pump problem interrupted dosing, and the study document does not report readings again until August 4.

How it was measured

Readings are reported as H2S concentration in parts per million, tracked on a near daily basis across both the iron compound period (January 26 to February 9) and the DRP Accelerator period (July 11 to August 12). The readings are the station’s own H2S monitor, as recorded in the study document. The study document does not name the person who took the readings. There is no separate untreated control station in the record. The comparison is the same lift station, first under the iron compound, then under DRP Accelerator.

Results

DRP Accelerator brought H2S down right away. On July 11, the first day of injection, the reading dropped from 280 ppm to 4 ppm that same day. An injection pump problem then interrupted the record, and the study document does not report readings again until August 4, when H2S had come down to 0 ppm and stayed there.

Date	H2S reading
July 11	280 ppm down to 4 ppm, same day
July 13 to August 2	Not reported. The study document says an injection pump problem interrupted the record during this stretch.
August 4	0 ppm
August 6	0 ppm
August 8	0 ppm
August 10	0 ppm
August 12	0 ppm

H2S held at 0 ppm for eight consecutive days across that stretch, with DRP Accelerator dosed continuously the whole time at 14 to 20 ppm. The study document draws the line plainly: the iron compound scavenges hydrogen sulfide after it forms, DRP Accelerator stops the formation from happening in the first place.

Limitations

This is one lift station over a short, interrupted record. The gap between July 11 and August 4, while the injection pump was down, means there is no continuous read on H2S through the whole transition. The study document does not disclose the station’s flow, loading, or whether anything else about the system changed during either period, so other factors behind the difference cannot be ruled out. There is no untreated control run alongside the DRP Accelerator period. The comparison is the same station’s iron compound record from earlier in the same study, not a side by side test. The study document does not name who ran the study or say what year it took place, so this case study cannot say whether it followed the same site survey and dosing protocol we use today. Results at another lift station depend on that station’s own flow, loading, and how far upstream the dose can reach. For a future customer, a result like this is a goal we measure, not a promise.

Proof assets

The study document, “Case History H2S Lift Station,” with its two charts: one plotting H2S readings against the iron compound dose, January 26 to February 9, and one plotting H2S readings against the DRP Accelerator dose, July 11 to August 12.
Waste Water Innovations is confirming the station’s written permission before naming it on this page.

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