Organic Filter Design Features
Aboveground filter system
Organic medium replaces or augments sand
Peat & leaf compost, two most common media
24 inch peat/sand filter bed
18 inch compost filter bed (proprietary system: CSF Treatment Systems, Inc.)
Exfiltration or underdrain system
Cover crop desirable for peat/sand system
Notes:
The organic filter functions the same as a surface sand filter design, but uses an organic medium as a replacement for or augmentation to sand. The most common organic filter media are compost and a peat/sand mixture. Designers have also experimented with other media such as forestry by-products, activated carbon, canaff, and zeolites. The use of an organic medium within a filtering system may offer increased pollutant removal efficiencies over sand alone (particularly with respect to nutrients).