Yu Guangwei, Tan Meijuan, Chong Yunxiao, Long Xinxian
Department of Environmental Science and Engineering, College of Natural Resource and Environment, South China Agricultural University, Guangzhou, 510642, China.
PLoS One. 2015 Jul 28;10(7):e0134010. doi: 10.1371/journal.pone.0134010. eCollection 2015.
For verification of spatial distribution of phosphorous retention capacity in constructed wetlands systems(CWs), two horizontal subsurface flow(HSSF) CWs and two vertical subsurface flow(VSSF) CWs, using sand as substrate and Typha latifolia as wetland plants, were constructed and put into use for synthetic wastewater treatment. Five months later, significant spatial variations of TP and inorganic phosphorus(Ca-P, Fe-P and Al-P) were observed, which were found to be greatly affected by CWs type and hydraulic loading. The results revealed that though spatial distribution of Fe-P and Al-P displayed a similar order of substrate content as "rhizosphere" > "near-rhizosphere" > "non-rhizosphere" and "inflow section" > "outflow section" regardless of types and loading, the distribution of Ca-P was positively correlated to that of Fe-P and Al-P in HSSF CWs, while negative correlation was shown in VSSF CWs. As a result, TP spatial distribution in HSSF CWs demonstrated a greater dissimilarity than that in VSSF CWs. For HSSF CWs with low hydraulic loading, the lowest TP content was found in non-rhizosphere substrate of outflow section, while the highest one was discovered in rhizonsphere substrate of inflow section. The values in 6 parts of areas ranged from 0.138 g·kg-1 to 2.710 g·kg-1, which also were from -33.5% to 1209% compared to the control value. On contrast, spatial difference of TP content in substrates of VSSF CWs was insignificant, with a variation ranging from 0.776 g·kg-1 to 1.080 g·kg-1, that was 275% to 421% higher than the control value. In addition, when hydraulic loading was increased, TP content in VSSF CWs sharply decreased, ranging from 0.210 g·kg-1 to 0.634 g·kg-1. Meanwhile, dissimilarity of TP spatial distribution in HSSF CWs was reduced, with TP content ranging from 0.258 g·kg-1 to 2.237 g·kg-1. The results suggested that P spatial distribution should be taken into account for CWs design and operation.
为验证人工湿地系统（CWs）中磷截留能力的空间分布，构建了两座以沙子为基质、宽叶香蒲为湿地植物的水平潜流（HSSF）CWs和两座垂直潜流（VSSF）CWs，并将其投入使用以处理合成废水。五个月后，观察到总磷（TP）和无机磷（Ca-P、Fe-P和Al-P）存在显著的空间变化，发现这些变化受CWs类型和水力负荷的显著影响。结果表明，尽管无论类型和负荷如何，Fe-P和Al-P的空间分布均呈现出类似的底物含量顺序，即“根际”>“近根际”>“非根际”以及“进水段”>“出水段”，但在HSSF CWs中，Ca-P的分布与Fe-P和Al-P呈正相关，而在VSSF CWs中呈负相关。因此，HSSF CWs中TP的空间分布比VSSF CWs表现出更大的差异。对于低水力负荷的HSSF CWs，出水段非根际底物中的TP含量最低，而进水段根际底物中的TP含量最高。六个区域的值在0.138 g·kg-1至2.710 g·kg-1之间，与对照值相比，其变化范围也在-33.5%至1209%之间。相比之下，VSSF CWs底物中TP含量的空间差异不显著，变化范围在0.776 g·kg-1至1.080 g·kg-1之间，比对照值高275%至421%。此外，当水力负荷增加时，VSSF CWs中的TP含量急剧下降，范围在0.210 g·kg-1至0.634 g·kg-1之间。同时，HSSF CWs中TP空间分布的差异减小，TP含量范围在0.258 g·kg-1至2.237 g·kg-1之间。结果表明，在CWs的设计和运行中应考虑磷的空间分布。
