Eliminating Hydrogen Sulfide Violations and Reducing COD in Food Processing Wastewater

Case Study Summary

This case study examines how Apex helped a food processing facility eliminate hydrogen sulfide (H₂S) violations and achieve a sustained reduction in chemical oxygen demand (COD) in its wastewater system. By implementing a targeted BioArmor™ biological control program, the facility resolved odor complaints, avoided regulatory fines, and stabilized wastewater performance.

Food processing facilities generate wastewater streams with high organic loading, making them particularly susceptible to hydrogen sulfide formation under anaerobic conditions. Elevated H₂S levels create strong odors, accelerate corrosion, and expose facilities to regulatory penalties, while high COD concentrations increase treatment costs and compliance risk.

A food processing facility operating an on-site wastewater lagoon system was experiencing recurring hydrogen sulfide violations, community odor complaints, and rising COD levels. These issues resulted in regulatory scrutiny and financial penalties. The facility partnered with Apex to implement a biological treatment strategy focused on addressing sulfide generation at its source.

Results at a Glance

Facility Background

• Industry: Food and Beverage
• Application: Wastewater Lagoon Treatment
• Primary Issue: Hydrogen sulfide exceedances, odors, high COD
• Apex Solution: BioArmor™ Biological Wastewater Treatment Program

The facility operates an extensive wastewater treatment system with multiple lagoons. Prior to working with Apex, the site was receiving frequent state fines due to hydrogen sulfide exceedances. Previous mitigation efforts included covering lagoons and tanks and using chemical sprays to neutralize H₂S in the air above the lagoons. While costly, these approaches were reactive and did not address H₂S generation within the wastewater itself.

The Challenge

The facility faced several compounding challenges:

• Chronic hydrogen sulfide exceedances leading to significant regulatory fines

• Odor complaints impacting compliance and community relations

• Elevated COD levels limiting lagoon performance

• Decades of accumulated organic sludge contributing to sulfate-reducing bacteria (SRB) activity

• High ongoing costs from reactive odor control strategies

A sustainable solution was needed to prevent H₂S formation, not just treat its symptoms.

The Apex Solution

Apex implemented a biological treatment program using BioArmor™, a blend of specialized Bacillus strains designed to target sulfur compounds and odorous volatile fatty acids.

Key components of the solution included:

• Initial large-volume dosing to establish microbial populations across all lagoons

• Ongoing monthly maintenance dosing to sustain performance

• Seasonal adjustment to BioArmor™ FRZ during winter months to maintain microbial activity

• Biological digestion of accumulated organic sludge, reducing SRB food sources

• Restoration of hydraulic capacity through gradual sludge reduction

This proactive biological approach reduced H₂S generation at its source while improving overall lagoon health.

Results & Operational Impact

The impact of BioArmor™ treatment was both immediate and long-lasting:

• Aqueous H₂S levels dropped from 40 mg/L to 1.5 mg/L within two weeks

• Odors were noticeably reduced within the first week of treatment

• Hydrogen sulfide exceedances were reduced by 99%, with zero fines issued since treatment began

• The state formally recognized the facility’s improvements, eliminating further enforcement actions

• COD levels dropped to record lows:

  • Lagoon COD decreased from 25,000 mg/L to under 5,000 mg/L in less than three weeks

  • COD further reduced from 28,700 mg/L to 1,116 mg/L after seven weeks

• Sludge digestion increased effective lagoon capacity, allowing dredging projects to be deferred

Together, these improvements resulted in millions of dollars in avoided fines, reduced chemical usage, and a more stable wastewater treatment system.

Applicable To

This solution is relevant for:

• Food and beverage processing facilities
• Industrial wastewater lagoon systems
• Operations experiencing hydrogen sulfide odors or violations
• Facilities facing elevated COD and regulatory scrutiny
• Plants seeking sustainable wastewater control strategies

Conclusion

By shifting from reactive odor control to proactive biological treatment, this food processing facility eliminated hydrogen sulfide exceedances, reduced COD, and restored regulatory confidence. BioArmor™ enabled sustainable wastewater performance improvements while delivering measurable financial and operational benefits.

For food and beverage processors facing odor issues, regulatory pressure, or lagoon performance challenges, Apex delivers biological solutions that address problems at the source — not just the surface.

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