Case Studies: Force Main Treatment

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Ozone-Based Hydrogen Sulfide (H₂S) Reduction to Eliminate Corrosion and Odor in Municipal Wastewater Systems

Overview

The following case studies highlight two municipal wastewater force main applications where ozone injection technology was implemented to control hydrogen sulfide (H₂S), to eliminate corrosion and odor. Both studies cut the chemical cost and usage, replacing them with ozone technology instead. In both cases, existing Bioxide® chemical treatment programs were replaced with on-site ozone generation systems to improve performance, reduce operating costs, and simplify operations.

Each installation demonstrates how ozone can provide reliable corrosion control, measurable H₂S reduction, and significant lifecycle cost savings in wastewater collection systems of varying sizes.

Background

Wastewater force mains are prone to anaerobic conditions that promote hydrogen sulfide formation, resulting in  corrosion concerns, odor complaints, and safety risks. Traditional chemical treatment programs, such as continuous Bioxide® dosing, are commonly used for sulfide control but can result in:

• High ongoing operating costs

• Continuous chemical delivery requirements

• Bulk chemical storage needs

• Operator handling and safety concerns

• Inconsistent treatment performance in some applications

The following case studies demonstrate how ozone technology was used as an alternative treatment method to address these challenges.

Proposed Solution: Remove Nasty Chemicals 

In both applications, ozone treatment was evaluated as a replacement for chemical dosing programs. The proposed approach included:

• On-site ozone generation

• Direct injection into wastewater force mains

• High-pressure injection for improved mass transfer

• Continuous oxidation of hydrogen sulfide within the pipeline

• Elimination of bulk chemical storage and handling

The goal was to achieve consistent H₂S reduction while reducing total lifecycle operating costs and simplifying system operations.  

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Ozone Treatment Solutions

Both systems were supplied by Oxidation Technologies and designed for direct force main injection applications.

Case Study 1

Municipal Wastewater Collection System - Green Bay, Wisconsin

System Overview

Results

The ozone system replaced a high-cost Bioxide® chemical program that required approximately $316,000 annually in operating expenses.

Following implementation, the system achieved:

• Improved odor control performance

• Significant reduction in hydrogen sulfide levels

• Elimination of chemical handling and storage

• Simplified system operations

Cost Impact

Payback Period: Less than 4 months

Case Study 1 Summary:

A municipal wastewater customer implemented ozone treatment technology to replace continuous Bioxide® chemical dosing for force main odor control and hydrogen sulfide (H₂S) reduction. The system treated wastewater flowing through a 1,000-foot force main where anaerobic conditions had created recurring odor concerns and measurable H₂S levels at the downstream manhole.

A 30 g/hr ozone injection system was installed to directly oxidize hydrogen sulfide within the force main. Following implementation, the municipality achieved consistent near-zero to 0 ppm H₂S readings while eliminating bulk chemical handling and simplifying daily operations.

The ozone system reduced annual operating costs from approximately $3,800 per year in chemical expenses to roughly $960 per year in electrical costs, while improving odor control performance and operational efficiency. The project highlights ozone’s effectiveness as a sustainable and reliable solution for smaller wastewater force main applications.

*View the Foce Main Application Page HERE

Case Study 2

Smaller Municipal Force Main Application - Green Bay, Wisconsin

System Overview

Results

The ozone system replaced a continuous Bioxide® dosing program and provided immediate operational improvements, including consistent near-zero hydrogen sulfide readings at the downstream manhole.

Key outcomes included:

• Consistent 0 ppm or near-zero H₂S readings

• Elimination of odor at discharge point

• Removal of chemical handling requirements

• Improved operational simplicity

Cost Impact

Case Study 2 Summary: 

A municipal wastewater system in Green Bay, Wisconsin implemented ozone treatment to replace continuous Bioxide® chemical dosing for force main odor control and hydrogen sulfide (H₂S) reduction. The system treated approximately 800,000 gallons per day flowing through a 12-inch, 7,800-foot force main where septic conditions were causing recurring odor issues, corrosion concerns, and elevated H₂S levels.

A 200 g/hr ozone injection system was installed to directly oxidize hydrogen sulfide within the force main under pressures up to 50 PSI. Following implementation, the municipality eliminated bulk chemical usage while improving odor control performance and reducing H₂S concentrations.

The ozone system reduced annual operating costs from approximately $316,000 in chemical expenses to about $19,200 in electricity and maintenance costs, while improving operational efficiency and simplifying system operation. The project demonstrates ozone’s effectiveness as a high-capacity, cost-saving solution for large municipal force main applications.

*View the Foce Main Application Page HERE

Overall Summary

Across both municipal applications, ozone injection technology demonstrated strong performance as an alternative to chemical-based force main treatment programs.

Key benefits observed included:

• Reliable hydrogen sulfide (H₂S) reduction

• Improved odor control performance

• Significant reduction in operating costs

• Elimination of chemical storage and handling

• Simplified maintenance and operation

• Strong return on investment across system sizes

These case studies illustrate the scalability of ozone technology, from small municipal systems to large high-flow force mains, while consistently delivering measurable operational and economic advantages.

Downloads

Force Main Treatment Brochure

Force Main Treatment Case Studies Brochure

*View the Foce Main Application Page HERE