Submitted to: Symposium on Biochemistry Of Wetlands
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/1996
Publication Date: N/A
Technical Abstract: Constructed wetlands are being investigated for their capability to treat swine wastewater after primary treatment in anaerobic lagoons. Six wetland cells (3.6 x 33.5 m) were constructed in Duplin Co., NC, in 1992. Four cells were planted to natural wetland vegetation in 1992. One set of two cells (two cells connected end-on-end) contained rush (Juncus effusus) and bulrushes (Scirpus americanus, Scirpus cyperinus and Scirpus validus), and another set of two cells contained bur-reed (Sparganium americanum) and cattails (Typha angustifolia and Typha latifolia). The third set of two cells contained two agronomic crops (soybean in saturated soil culture, and rice, respectively). During the vegetative period, plant materials were clipped each month from three 0.25-m2 quadrants chosen at random along each wetland cell with marsh vegetation. Oven dry weights of living and dead tissues were used to estimate the net aboveground plant productivity. Soybean and rice plants were clipped at harvest, and all dead plant material on the ground was collected. Plant tissue subsamples were digested and analyzed for total nitrogen and total phosphorus. Aboveground biomass production as high as 39 Mg/ha/yr was estimated for the bur-reed/cattails plant community. Agronomic crops had lower dry matter accumulation (<15 Mg/ha/yr), but they offer an economically feasible way to remove nutrients.