PARENT SESSION
Poster Session #21: Riparian and Wetland Restoration.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Screening plant species for use in constructed wetlands.

Christ, Martin¹, Coleman, Jerry^*,1,2, Garbutt, Keith¹, Sexstone, Alan¹, ¹ West Virginia University, Morgantown, WV² Montgomery County Community College, Blue Bell, PA

ABSTRACT- Constructed wetlands (CWs) can be used to treat household wastewater. Increasing the number of species known to be effective in CWs may increase the range of sites where CWs are viable. We tested eight species for viability in CWs by growing them in drained, flooded, and "reduced" soils. Reduced conditions were established by flooding the soils with a solution of sucrose. We measured responses to growing conditions in shoot mass, root length, soil redox potential, and root oxygen leakage (ROL), which was quantified by estimating length of roots oxidizing an agar medium containing a redox indicator. Relative to the drained treatment, reduced conditions decreased growth of Acorus and Iris and of the non-wetland control, Zea, whereas growth of Juncus, Phalaris, Pontederia and Typha was insensitive to treatment. Among the pots in the flooded treatment, those with Zea had lower EH values. Pots in the reduced treatment all had lower EH values, with no difference among species. Zea plants had only 0 to 3 cm of oxidizing roots. Under flooded conditions, Acorus, Iris, and Pontederia had the most oxidizing roots (~75 cm/plant). Under reduced conditions, oxidizing roots in Pontederia increased (~95 cm/plant), whereas other species had no more than approximately 30 cm/plant. For CWs with extremely reduced soils, Pontederia has the advantages of maintaining good growth and root oxidation. For CWs with soils that are merely flooded, many species maintain high EH values, growth, and root oxidation.

KEY WORDS: constructed wetlands, wastewater treatment, root oxygen leakage, root length