In 2015 California introduced new limits on stormwater discharge from industrial facilities, placing stricter controls on the levels of pollutants that may be discharged on an ongoing basis or as a result of a single storm event.

Facilities require a discharge permit under the National Pollutant Discharge Elimination System (NPDES) permit program, and the new regulations mean that in order to obtain a permit businesses must demonstrate reduced discharge of controlled pollutants.

The management team of a supplier to the aerospace and electronics industries was concerned that the stormwater effluent from its facility contained aluminum, zinc, iron and copper at levels above the new discharge limits.

At the levels in question the business risked facing significant financial and legal penalties, as well as associated reputational damage.

The management team developed a Stormwater Treatment Action Plan, but as part of that plan they needed to identify treatment technologies that would meet their site’s specific needs.

The management team identified the Hydro-Industrial Stormwater Filter as a potential solution, and they engaged Hydro International to undertake a characterization study of their stormwater effluent and to perform performance testing of the filter.

Runoff samples were sent to Hydro International’s hydraulics laboratory, where the samples were tested on the Hydro-Industrial Stormwater Filter.

Performance testing of the site’s effluent revealed that the Hydro-Industrial Stormwater Filter could reduce all of the effluent metals to beneath discharge limits, as well as reducing other pollutants:

• Zinc capture of up to 97%
• Aluminum capture of up to 95%
• Iron capture of up to 92%
• Copper capture of up to 89%

Incorporation of the Hydro-Industrial Stormwater Filter ensured that the management team could implement their Stormwater Treatment Action Plan effectively—and the risks of financial and legal penalties that had been facing them were removed.