Chemical and Environmental Engineering Department, Tomar High School of Technology, Tomar Polytechnic Institute, Campus da Quinta do Contador, Estrada da Serra, Tomar, Portugal.
Water Environ Res. 2010 Feb;82(2):128-37. doi: 10.2175/106143009x447894.
Constructed wetlands, which facilitate phosphorus removal via precipitation, adsorption, and biological assimilation, offer a promising appropriate technology for advanced treatment in wastewater treatment plants. Because adsorption and precipitation are pointed out as the major phosphorus-removal mechanisms, the selection of a medium with high phosphorus-sorption capacity is important to obtain a sustained phosphorus removal. The objective of this study was to evaluate two kinds of lightweight expanded clay aggregates (LWAs)--Filtralite NR and Filtralite MR (Maxit Group, Avelar, Portugal)--as substrates in constructed wetlands to improve phosphorus-removal performance. Laboratory experiments were performed to test the potential of the LWAs to remove phosphorus from a phosphate solution. The experimental data were well-fitted by both the Langmuir and Freundlich isotherm models. Pilot-scale investigations were carried out to evaluate the phosphorus removal under field conditions. Four subsurface constructed wetlands were operated since June 2002; two of them were planted with Phragmites australis, and the other two were unplanted. The beds were filled with the two kinds of LWAs. Total phosphorous and pH were monitored since 2003, at a mean hydraulic load of 50 +/- 4 L/(m2 x d), during 6 years. The inflow phosphorus concentration was in the range 4 to 13 mg/L. Under the conditions used, beds with Filtralite MR had better efficiency, and the bed with Filtralite MR planted with Phragmites australis provided a phosphorus effluent mean concentration of 0.7 +/- 0.2 mg/L, during the trial period. This study presents the first long-term pilot-scale data for constructed wetlands using LWAs.
人工湿地通过沉淀、吸附和生物同化来促进磷的去除，为污水处理厂的深度处理提供了一种很有前景的适用技术。由于吸附和沉淀被认为是主要的除磷机制，因此选择具有高磷吸附能力的介质对于获得持续的除磷效果非常重要。本研究旨在评估两种轻质膨胀粘土骨料（LWAs）——Filtralite NR 和 Filtralite MR（Maxit Group，Avelar，葡萄牙）——作为人工湿地的基质，以提高除磷性能。进行了实验室实验以测试 LWAs 从磷酸盐溶液中去除磷的潜力。实验数据很好地符合 Langmuir 和 Freundlich 等温模型。进行了中试研究以评估现场条件下的磷去除情况。自 2002 年 6 月以来，四个地下式人工湿地投入运行；其中两个种植了芦苇，另外两个没有种植。床体填充了两种 LWAs。自 2003 年以来，在 6 年的时间里，在平均水力负荷为 50 ± 4 L/（m2 x d）的条件下，监测总磷和 pH 值。进水磷浓度在 4 至 13 mg/L 之间。在使用的条件下，Filtralite MR 床的效率更高，种植芦苇的 Filtralite MR 床的磷出口平均浓度为 0.7 ± 0.2 mg/L，在试验期间。本研究首次提供了使用 LWAs 的人工湿地长期中试数据。
