A recycling and transfer station in Northern California was discharging surface water runoff that was over the Numeric Action Levels for five different pollutants, including Total Suspended Solids (TSS), zinc, copper, aluminium and iron. Some of these pollutants were being discharged at as much as seven times the permissible limits. 

The facility had investigated a range of industrial stormwater treatment options to tackle this issue, but had either been unconvinced of the effectiveness of the treatment technologies or had adjudged that the cost was prohibitive. 

The company could not afford to delay a decision any longer, however, as a local non-profit environmental advocacy group was threatening to take the business to court if the facility did not reduce its industrial stormwater effluent discharge levels to within the those permissible under the California Industrial General Permit (IGP).

The recycling center approached Hydro International and arranged for a sample of its stormwater to be assessed. Runoff samples were taken from the facility and sent for a Pollutant Removal Test conducted in the Hydro International hydraulics laboratory. 

Hydro International demonstrated extremely high removal levels using Hydro-Industrial™ Stormwater Filter membrane media for all five pollutants of concern. In all instances, the Hydro-Industrial™ Stormwater Filter brought the facility under the Numeric Action Levels that they needed to meet.

Testing demonstrated that the Hydro-Industrial™ Stormwater Filter achieved removal rates of 80-97% across the target pollutants.

The recycling center determined that the filter was a cost-effective way to meet its discharge limits and prevent legal action.