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Oxygen transfer in marsh-pond-marsh constructed wetlands treating swine wastewater
BibTeX
@MISC{Ro_oxygentransfer,
author = {Kyoung S. Ro and Patrick G. Hunt and Melvin H. Johnson and Terry A. Matheny and Dean Forbes and Gudigopuram B. Reddy},
title = {Oxygen transfer in marsh-pond-marsh constructed wetlands treating swine wastewater},
year = {}
}
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Abstract
Oxygen transfer efficiencies of various components of the marsh-pond-marsh (M-P-M) and marsh-floating bed-marsh (M-FB-M) wetlands treating swine wastewater were determined by performing oxygen mass balance around the wetlands. Biological oxygen demand (BOD) and total nitrogen (TN) loading and escaping rates from each wetland were used to calculate carbonaceous and nitrogenous oxygen demands. Ammonia emissions were measured using a wind tunnel. Oxygen transfer efficiencies of the aerated ponds were estimated by conducting the ASCE standard oxygen transfer test in a tank using the same aeration device. Covering pond water surface with the floating bed slightly decreased oxygen transfer efficiency. The diffused membrane aeration (26.7 kg O2 ha-1 d-1) of M-P-M was surprisingly not as effective as plant aeration in the marsh (38.9 to 42.0 kg O2 ha-1 d-1). This unusually low oxygen transfer efficiency of the diffused aeration was attributed to its low submergence depth of 0.8 m compared to typical depth of 4.5 m. The wetlands consisting entirely of marsh removed similar amounts of C and N without investing additional equipment and energy costs of aerating ponds in the middle of wetlands.
Keyphrases
swine wastewater oxygen transfer oxygen transfer efficiency marsh-pond-marsh constructed wetland kg o2 ha-1 d-1 plant aeration pond water surface low submergence depth biological oxygen demand marsh-floating bed-marsh oxygen mass balance nitrogenous oxygen demand aerated pond asce standard oxygen transfer test diffused membrane aeration additional equipment diffused aeration energy cost total nitrogen wind tunnel typical depth ammonia emission various component low oxygen transfer efficiency aeration device similar amount
