Allen Winthrop C, Hook Paul B, Biederman Joel A, Stein Otto R
CH2M HILL, Los Angeles, CA 90071, USA.
J Environ Qual. 2002 May-Jun;31(3):1010-6. doi: 10.2134/jeq2002.1010.
Constructed wetlands are widely used for wastewater treatment, but there is little information on processes affecting their performance in cold climates, effects of plants on seasonal performance, or plant selection for cold regions. We evaluated the effects of three plant species on seasonal removal of dissolved organic matter (OM) (measured by chemical oxygen demand and dissolved organic carbon) and root zone oxidation status (measured by redox potential [Eh] and sulfate [SO4(2-)]) in subsurface-flow wetland (SSW) microcosms. A series of 20-d incubations of simulated wastewater was conducted during a 28-mo greenhouse study at temperatures from 4 to 24 degrees C. Presence and species of plants strongly affected seasonal differences in OM removal and root zone oxidation. All plants enhanced OM removal compared with unplanted controls, but plant effects and differences among species were much greater at 4 degrees C, during dormancy, than at 24 degrees C, during the growing season. Low temperatures were associated with decreased OM removal in unplanted controls and broadleaf cattail (Typha latifolia L.) microcosms and with increased removal in beaked sedge (Carex rostrata Stokes) and hardstem bulrush [Schoenoplectus acutus (Muhl. ex Bigelow) A. & D. Löve var. acutus] microcosms. Differences in OM removal corresponded to species' apparent abilities to increase root zone oxygen supply. Sedge and bulrush significantly raised Eh values and SO4(2-) concentrations, particularly at 4 degrees C. These results add to evidence that SSWs can be effective in cold climates and suggest that plant species selection may be especially important to optimizing SSW performance in cold climates.
人工湿地被广泛用于污水处理，但关于寒冷气候下影响其性能的过程、植物对季节性性能的影响或寒冷地区植物选择的信息却很少。我们评估了三种植物物种对潜流湿地（SSW）微观世界中溶解有机物（OM）（通过化学需氧量和溶解有机碳测量）的季节性去除以及根区氧化状态（通过氧化还原电位[Eh]和硫酸盐[SO4(2-)]测量）的影响。在一个为期28个月的温室研究中，在4至24摄氏度的温度下，对模拟废水进行了一系列为期20天的培养。植物的存在和物种强烈影响了OM去除和根区氧化的季节性差异。与未种植的对照相比，所有植物都增强了OM的去除，但在休眠期4摄氏度时，植物的影响和物种间的差异比在生长季节24摄氏度时要大得多。低温与未种植对照和阔叶香蒲（Typha latifolia L.）微观世界中OM去除的减少相关，而与喙叶苔草（Carex rostrata Stokes）和硬茎芦苇[Schoenoplectus acutus (Muhl. ex Bigelow) A. & D. Löve var. acutus]微观世界中去除的增加相关。OM去除的差异对应于物种增加根区氧气供应的明显能力。苔草和芦苇显著提高了Eh值和SO4(2-)浓度，特别是在4摄氏度时。这些结果进一步证明了SSW在寒冷气候下可以有效，并表明植物物种选择对于优化寒冷气候下SSW的性能可能尤为重要。
