USDA-ARS Coastal Plains Soil, Water & Plant Research Center, Florence, South Carolina 29501, USA.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2010;45(3):377-82. doi: 10.1080/10934520903467998.
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.
通过在湿地周围进行氧质量平衡，确定了处理猪废水的沼泽-池塘-沼泽（M-P-M）和沼泽-浮床-沼泽（M-FB-M）湿地各组成部分的氧转移效率。利用湿地的生物需氧量（BOD）和总氮（TN）负荷以及每种湿地的逃逸率来计算碳素和氮素需氧量。使用风洞测量氨排放。通过在使用相同曝气装置的罐中进行 ASCE 标准氧转移测试，估算了曝气池的氧转移效率。用浮床覆盖池塘水面会略微降低氧转移效率。M-P-M 的扩散膜曝气（26.7 kg O2 ha-1 d-1）的效果并不如沼泽中的植物曝气（38.9 至 42.0 kg O2 ha-1 d-1）那样有效。这种扩散曝气异常低的氧转移效率归因于其 0.8 米的低淹没深度，而典型深度为 4.5 米。完全由沼泽组成的湿地在不投资中间曝气池的额外设备和能源成本的情况下，去除了相同数量的 C 和 N。
