If your facility’s water supply smells like rotten eggs, the cause is almost certainly hydrogen sulfide. H2S is a naturally occurring dissolved gas found in groundwater sources across the United States, particularly in areas with high organic matter content, sulfur-rich geological formations, and anaerobic aquifer conditions. It is common in the Gulf Coast, Florida, the Pacific Northwest, and many agricultural regions where well water draws from deep anaerobic aquifers.

For industrial facilities that draw from groundwater sources or process water systems affected by biological activity, H2S removal from water is not a cosmetic concern. It is a corrosion risk, a health and safety issue, a process interference problem, and in confined spaces, a potential life safety hazard. Understanding where it comes from, what it does to your facility, and how to remove it effectively is an operational priority that becomes more pressing as temperatures drop heading into winter and enclosed plant spaces reduce natural ventilation.

What Is Hydrogen Sulfide and Where Does It Come From in Industrial Water?

Hydrogen sulfide (H2S) is a dissolved gas that forms in water through two primary mechanisms. The first is chemical reduction of sulfate ions by sulfate-reducing bacteria (SRB) in anaerobic conditions. The second is decomposition of organic matter containing sulfur compounds under anaerobic conditions. Both processes occur naturally in deep groundwater aquifers and in any enclosed water system where oxygen is depleted and biological activity is present.

In industrial water systems, H2S sources include:

• Groundwater wells: Drawing from sulfur-bearing geological formations or deep anaerobic aquifers where SRB activity is established.
• Process water recirculation systems: Where anaerobic conditions develop in storage tanks, dead legs, and low-flow pipework sections.
• Cooling tower systems: Where biological activity in the warm, oxygen-depleted water creates conditions for SRB growth.
• Wastewater and produced water streams: In oil and gas, mining, and chemical processing where H2S concentrations can reach significantly elevated levels.

H2S concentration in groundwater varies widely, from trace levels detectable only by smell at concentrations below 0.5 ppm, through moderate levels of 1 to 10 ppm that cause significant operational problems, to high concentrations above 10 ppm that require engineered treatment systems capable of handling substantial dissolved gas loads.

Why H2S Is a Serious Problem for Industrial Facilities

Corrosion of Metal Infrastructure

Hydrogen sulfide is highly corrosive to a wide range of metals used in industrial water systems. It attacks copper, brass, and bronze components aggressively, causing rapid degradation of fittings, heat exchangers, instrumentation, and pump components. It also corrodes iron and steel through sulfide stress corrosion cracking, a particularly damaging failure mode in high-pressure systems where cracking can cause sudden component failure rather than gradual degradation.

For facilities with extensive copper or brass fittings in their water distribution or treatment systems, even moderate H2S concentrations cause measurable corrosion within months of exposure. The cost of corrosion-related component replacement, in addition to the operational disruption of unexpected failures, significantly exceeds the cost of H2S removal treatment.

Process Interference

In food and beverage, pharmaceutical, and chemical processing applications, H2S in process water affects product quality directly. It imparts odour and taste to products that contact the water, interferes with certain chemical reactions, and can cause discolouration in finished products where sulfide compounds react with trace metals or other process chemicals.

For facilities where water contacts the finished product at any stage, H2S concentrations that are operationally tolerable in a cooling system or utility water application are completely unacceptable in process water.

Health, Safety, and Compliance

H2S is toxic at relatively low airborne concentrations. The OSHA permissible exposure limit (PEL) for H2S is 20 ppm as a ceiling concentration, with a peak allowable concentration of 50 ppm for no more than 10 minutes. At concentrations above 100 ppm, H2S causes rapid incapacitation. Above 500 ppm, it is immediately dangerous to life and health.

In enclosed plant spaces where water containing dissolved H2S is pumped, heated, or agitated, H2S degasses from solution into the surrounding air. Pump rooms, tank farms, and enclosed treatment areas where groundwater with elevated H2S is handled require ventilation design and atmospheric monitoring appropriate to the H2S concentration in the source water. As temperatures drop in autumn and winter, ventilation rates in enclosed plant spaces typically decrease, increasing the risk of H2S accumulation to hazardous levels.

H2S Removal Methods for Industrial Water Treatment

Several treatment technologies are available for H2S removal from industrial water supplies. The correct selection depends on H2S concentration, daily flow volume, the presence of other contaminants requiring simultaneous treatment, and the downstream application for the treated water.

Aeration and Degassing

For moderate H2S concentrations typically below 5 to 10 ppm, aeration or forced draft degassing is often the most cost-effective primary treatment approach. Aeration introduces air into the water stream, which oxidizes dissolved H2S and drives it out of solution as a gas that is vented to atmosphere or captured for treatment.

Packed tower aerators and cascade aeration systems are common configurations for continuous industrial flow rates. Degassing membrane systems provide an alternative where atmospheric venting is not practical and where the H2S concentration in the airstream must be controlled.

The limitation of aeration as a standalone treatment is that it does not remove residual H2S completely at higher concentrations, and it introduces dissolved oxygen into the treated water, which may be undesirable in certain process applications or where downstream RO membranes need to be protected from oxidizing conditions.

Oxidation with Chemical Treatment

Chlorination, chlorine dioxide, and hydrogen peroxide oxidation convert dissolved H2S to elemental sulfur or sulfate, both of which are non-volatile and non-odorous. Chemical oxidation is effective across a wide range of H2S concentrations and can be implemented as a continuous dosing system that scales to match flow variation.

However, chlorination upstream of RO membranes requires dechlorination before the RO feed to prevent membrane oxidation damage. This adds a carbon filtration or sodium metabisulfite dosing stage that increases system complexity and operating cost.

Multimedia Filtration with Oxidizing Media

Oxidizing filter media including manganese greensand, Birm, and catalytic carbon media can oxidize and remove H2S from water as it passes through the filter bed. These systems work well for low to moderate H2S concentrations and have the advantage of simultaneous iron and manganese removal, which often co-occur with H2S in groundwater sources. Learn more about ADVANCEES pre- and post-treatment systems.

Reverse Osmosis

RO membranes do not remove dissolved gases including H2S directly, because dissolved gases pass through semi-permeable membranes alongside water molecules. However, RO is highly effective for removing the sulfate ions that fuel sulfate-reducing bacteria activity, reducing the ongoing biological generation of H2S in recirculating systems.

For applications where H2S co-occurs with high TDS, heavy metals, or other dissolved contaminants requiring RO treatment, the correct treatment train typically positions H2S removal upstream of the RO system to protect membranes and pre-treatment components from the corrosive and fouling effects of elevated H2S in the feed stream.

Designing an H2S Removal System for Your Facility

H2S removal system design for an industrial application requires water quality analysis that goes beyond a simple H2S concentration measurement. The correct design depends on the full water chemistry profile including pH, dissolved oxygen, iron and manganese concentrations, total hardness, TDS, and biological activity indicators, all of which interact with H2S treatment chemistry and influence which removal approach is most appropriate and cost-effective for your specific source water.

A treatment system that effectively removes H2S from one facility’s groundwater may perform poorly on another site’s source water with a different chemistry profile, even at similar H2S concentrations. This is why pre-design water analysis and engineering review are essential steps before committing to a specific treatment technology.

ADVANCEES provides specialist RO plant design and consultancy support for H2S removal from industrial water supplies, from initial water quality assessment through to full treatment train design and system supply. Our engineering team has experience with hydrogen sulfide removal across a wide range of industrial applications and source water chemistries, and can recommend the right treatment approach for your facility’s specific conditions.

Act Before Winter Reduces Your Margin for Error

H2S problems in industrial facilities typically worsen in winter. Reduced ventilation in enclosed plant spaces concentrates airborne H2S from degassing water. Cold temperatures slow the aerobic biological activity that competes with sulfate-reducing bacteria, allowing SRB populations to grow in water storage and distribution systems. And facilities returning from summer shutdown may be restarting systems that have developed H2S problems during an extended period of reduced flow and stagnant conditions.

Addressing H2S removal before winter means your facility enters the lowest-ventilation season with a treatment system in place rather than discovering the problem when airborne concentrations in enclosed spaces become a health and safety concern.

Contact ADVANCEES today to discuss H2S testing, source water analysis, and the right H2S removal water treatment system for your industrial facility.