Effect of media type and particle size on dissolved organic carbon release from woody filtration media.

Sequential batch leaching tests were used to evaluate the mass of DOC released from composted garden organics (yard waste), pine and hardwood under pseudo-equilibrium conditions. All media showed an initial rapid decline in DOC values followed by a slower rate during later time periods. Greater than 50% of the DOC leached occurred within the initial time period (<24 h). The mass of DOC leached varied significantly between the materials and to a lesser degree between different particle size ranges. The pine had the lowest leached DOC fraction (2.8-4.8 mg/g), while the hardwood (21-27 mg/g) and compost (13.6-32.7 mg/g) were significantly greater. The type and processing of the woody material incorporated into these systems can have a significant impact on the treated stormwater.