How the 75 GPM System Solved Stormwater Challenges at Two Industrial Facilities in Southern California
How the 75 GPM System Solved Stormwater Challenges at Two Industrial Facilities in Southern California
Overview
Industrial facilities operating under the California Industrial General Permit (IGP) often face challenges meeting Numeric Action Levels (NALs) and Total Maximum Daily Load (TMDL) requirements, especially when runoff contains elevated metals, sediment, nutrients, or oil and grease.
To address these challenges, Frog Environmental deployed its 75 GPM Stormwater Treatment System at two industrial facilities with documented stormwater exceedances. The results demonstrate how a compact, modular system can deliver measurable pollutant reductions and consistent regulatory compliance.
The Challenge
Two industrial facilities, one specializing in steel manufacturing and another in structural steel fabrication, experienced elevated pollutant concentrations in stormwater discharges associated with outdoor operations and material handling.
Both sites required a treatment solution that could:
Reduce metals, sediment, nutrients, and hydrocarbons
Meet applicable CA IGP Numeric Action Levels (NALs) and TMDL Numeric Effluent Limits (NELs)
Be deployed quickly without permanent infrastructure changes
To meet these needs, Frog Environmental installed 75 GPM modular stormwater treatment systems designed to treat runoff prior to discharge.
Facility 1: Industrial Steel Manufacturing Facility
Site Conditions
This facility manufactures plastic-coated steel cables and bars. Stormwater runoff from outdoor operations contained elevated concentrations of:
Total Suspended Solids (TSS)
Oil & Grease (HEM)
Aluminum (Al)
Iron (Fe)
Zinc (Zn)
Nitrate + Nitrite (N+N)
Sampling data showed exceedances of CA IGP NALs and TMDL limits, placing the facility at risk of continued non-compliance.
Treatment Solution
A 75 GPM stormwater treatment system was installed, consisting of:
Stormwater storage to manage peak runoff volumes
Media-based treatment modules engineered for metals, nutrients, sediment, and hydrocarbons
The system was designed to treat stormwater during qualifying rain events while maintaining operational flexibility.
Performance Results
Post-treatment sampling confirmed significant reductions across all monitored constituents. Annual average results showed:
98.2% reduction in TSS
85.4% reduction in Oil & Grease
94–98% reduction in metals (Al, Fe, Zn)
94.9% reduction in Nitrate + Nitrite
All regulated parameters were reduced to below applicable CA IGP NALs and TMDL limits, allowing the facility to return to compliance.
Facility 2: Structural Steel Fabrication Facility
Site Conditions
This facility performs outdoor steel fabrication and material storage. Stormwater runoff contained elevated concentrations of:
Total Suspended Solids (TSS)
Aluminum (Al)
Iron (Fe)
Zinc (Zn)
The facility required a compact, reliable treatment system capable of consistent performance during storm events.
Treatment Solution
A 75 GPM modular stormwater treatment system was deployed, featuring:
Temporary stormwater storage
Media-filled treatment modules optimized for metals and sediment removal
The system footprint was minimized to fit site constraints while still achieving effective treatment.
Performance Results
Stormwater sampling following installation demonstrated that:
All monitored pollutants were reduced below CA IGP NAL thresholds
Metals and sediment reductions exceeded 90%
The system performed consistently across multiple storm events
Influent vs. Effluent Performance Summary
Across both facilities, the 75 GPM system demonstrated documented, data-backed treatment performance, including:
Up to 98% pollutant removal efficiency
Reliable reduction of metals, nutrients, sediment, and oil & grease
Compliance with CA IGP NALs and applicable TMDL requirements
These results confirm that the 75 GPM system delivers the same proven treatment strategy used at larger industrial sites, now optimized for lower flows and faster deployment.
Key Takeaways
- The 75 GPM Stormwater Treatment System provides industrial-grade treatment in a compact, modular configuration
- Proven media technology delivers consistent reductions across a wide range of pollutants
- Ideal for facilities seeking fast, flexible compliance solutions without permanent infrastructure
Proven Results. Scalable Performance.
The 75 GPM Stormwater Treatment System brings Frog Environmental’s field-tested treatment approach to sites with smaller flow requirements, without compromising performance or compliance confidence.
Looking for a right-sized stormwater solution?
Contact Frog Environmental to learn how the 75 GPM system can support your site’s compliance goals.
📞Call: 310-241-0866
📧 Email: sales@frogenv.com
🌐 Website: https://www.frogenv.com/stormwater-treatment-systems