Description
Alternative media filters use filtration media other than sand, such as peat, compost, activated alumina, or zeolite to filter out, or strain, particles and particle-bound constituents found in stormwater. Stormwater pollutants are removed through physical, chemical, and biological processes, including filtration, adsorption, microbial activity, and decomposition. Common constituents that are removed include total suspended solids (TSS), total phosphorus, total metals, microbiological constituents, and litter, but alternative media filters can also have the potential to remove dissolved constituents such as metals, nutrients, and trace organics (which sand filters do not remove particularly well).
Experience
Kristar Perk Filter™
The Kristar Perk Filter™ Study is a laboratory evaluation of the hydraulic and treatment performance of a proprietary canister filter BMP. Clean water was used to estimate hydraulic capacity at different water depths up to bypass conditions. Pollutant removal was estimated by measuring the water quality before and after loading the filters with synthetic stormwater. Both ground silica and street dust were used as a sediment source.
OWP Tasks
- Developed Study Plan
- Conducted Laboratory Experiments
- Analyzed Data
- Provided Consultation for Product Development
- Prepared Reports
Report/Study Link:
KriStar Perk Filter™
OWP Contacts: Brian Currier
Caltrans Tahoe Basin Small-Scale Pilot Studies – Alternative Media Filters
The Caltrans Tahoe Basin Stormwater Pilot Program consists of both small-scale and full-scale pilot studies. Small-scale alternative media filter columns were constructed and operated intermittently to treat discrete batches of stormwater collected from various runoff events. Filters that use media other than sand have the potential to remove dissolved constituents such as nutrients, metals, and trace organics that are not removed particularly well by sand. The primary objective of this study was to determine the expected performance of alternative media filters in removing turbidity and nutrients from Tahoe stormwater runoff. As well as determining the performance of various alternative media (e.g., activated alumina, limestone, iron oxide), this study evaluated the effect of chemical addition and the hydraulic benefits of fabric prefiltration and graded media.
OWP Tasks
- Assisted in Study Planning
- Reviewed Experimental Designs and Methods
- Provided Technical Assistance
- Assessed Study Results
- Reviewed Study Reports and Recommendations
Report/Study Link:
Caltrans Tahoe Basin Small-Scale Pilot Studies – Alternative Media Filters
OWP Contacts: Dipen Patel | John Johnston
Caltrans Tahoe Basin Full-Scale Pilot Studies – Alternative Media Filters
As part of the Caltrans Tahoe Basin Stormwater Pilot Program, six full-scale Austin-type filters and two small footprint vault filters were designed, constructed, and monitored on Hwy 50 and SR 267. These alternative media filters utilized activated alumina, iron-modified activated alumina, or limestone media. Filters that use media other than sand have the potential to remove dissolved constituents such as nutrients, metals, and trace organics that are not removed particularly well by sand. The objectives of these studies were to determine the effectiveness of alternative media filters in removing fine particles, turbidity, and nutrients; hydraulic performance of the filters in the alpine climate; maintenance requirements; and construction and maintenance costs. These data were compared to regulatory effluent limits, and load removal assessments were made to compare with expected requirements in the Lake Tahoe TMDL.
OWP Tasks
- Assisted in Study Planning
- Reviewed Designs of Monitoring Systems
- Provided Technical Assistance During Design, Construction, and Monitoring
- Assessed Study Results
Report/Study Link:
Caltrans Tahoe Basin Full-Scale Pilot Studies – Alternative Media Filters
OWP Contacts: Dipen Patel
Caltrans Compost Stormwater Filter System
The CSF System Study was a two-year study conducted in Orange County along State Route 73. The primary objective was to assess the effectiveness of the existing stormwater Best Management Practices (BMPs)—the CSF Systems. Other objectives included assessing the quality of runoff from State Route 73, assessing if the CSF Systems were exporting nutrients, and assessing if exporting nutrients were resulting in the impairment of water quality and beneficial uses. For each of three sites, influent and effluent water quality samples were collected and compared. Visual inspections of the receiving waters assessed whether eutrophication was occurring.
OWP Tasks
- Assisted in Study Planning
- Provided Monitoring Assistance
- Reviewed Data Assessment and Reporting
Report/Study Link:
Caltrans Compost Stormwater Filter System
OWP Contacts: David Alderete
Kristar TreePod® Filter
The Kristar TreePod® study was a laboratory evaluation of the hydraulic and pollutant reduction performance of a non-proprietary, modular bioretention BMP for stormwater treatment. Clean water was used to estimate hydraulic capacity at different water depths up to bypass conditions. Pollutant removal was estimated by measuring the water quality of the influent and effluent of the filter. Representative influent concentrations were achieved by using street dust that was collected from street sweepers and sieved to exclude particles larger than 75 microns.
OWP Tasks
- Developed Study Plan
- Conducted Laboratory Experiments
- Analyzed Data
- Provided Consultation for Product Development
- Prepared Reports
Report/Study Link:
KriStar TreePod Filter™
OWP Contacts: Brian Currier
