J. W. Rogers, D. T. Hill, V.W.E. Payne, S.R. Kown 2
An 8-month field study has been completed to evaluate the treatment of poultry wastewater by a vegetated wetland compared to a model wetland containing inert dowel rods. A free water surface constructed wetland was installed at the Auburn University Poultry Unit in Auburn, Alabama to treat effluent from an anaerobic poultry waste lagoon. The wetland system consisted of three series of dual cell wetlands. One series (two cells) contained Sagittaria lancifolia to provide an approximate 10% plant fill volume; one series contained Phragmites australis and Scirpus spp. to provide an approximate 5% plant fill volume; the third series was not vegetated which allowed comparison of the blank to the vegetated cells. Two series of model ponds were constructed in the first cell of the blank series. These model ponds were scaled down versions (1:9) of the larger wetland ponds. Wooden dowel rods were added to the model ponds to provide an inert growth medium for bacteria and provide an equivalent fill volume as the full size ponds. Results showed that treatment by the vegetated systems was higher than treatment by the dowel systems. The BOD5 concentration was reduced by 45 to 50% in the vegetated cells while 30 to 35% BOD5 concentration reduction occurred in the dowel systems. Similarly TKN reduction was higher in the vegetated series (42-57%) compared to the dowel series (20-27%). The total study period was broken down into seasonal periods to investigate the treatment differences between the vegetated cells and the dowel cells.
