生物炭和混凝土渣在人工湿地中除磷效应的对比

为了寻找适合西北农村地区人工湿地的除磷填料,结合西北地区温度特征,对混凝土渣和生物炭2种填料的除磷效应进行了对比研究;基于等温吸附实验和动力学吸附实验,构建了2种静态潜流人工湿地;通过模拟运行,对比验证了2种填料对生活污水中磷酸盐($ {{rm{PO}}_{rm{4}}^{{rm{3 - }}}}$-P)的去除效果和稳定性。结果表明：与生物炭相比,混凝土渣对${ {rm{PO}}_{rm{4}}^{{rm{3 - }}}}$-P吸附作用较好,吸附速率最快、吸附量最高达到了2.206 mg·g⁻¹;混凝土渣对$ {{rm{PO}}_{rm{4}}^{{rm{3 - }}}}$-P吸附既有单层吸附,又有多层吸附,说明其吸附过程是非均匀的,而生物炭对$ {{rm{PO}}_{rm{4}}^{{rm{3 - }}}}$-P的吸附多为单层吸附;在加入生活污水且$ {{rm{PO}}_{rm{4}}^{{rm{3 - }}}}$-P平均浓度为4.6 mg·L⁻¹的条件下,水力停留时间(HRT)达到24 h后,混凝土渣湿地和生物炭湿地对$ {{rm{PO}}_{rm{4}}^{{rm{3 - }}}}$-P的去除率分别达到了94.86%和86.37%。综合对比,混凝土渣更适宜作为西北地区潜流人工湿地除磷填料。以上研究结果可为人工湿地除磷提供选材参考。

Comparation of phosphorus removal effect of biochar and concrete slag in constructed wetland

In order to find the phosphorus removal filler suitable for constructed wetlands in the Northwest rural areas, in combination with the temperature characteristics in the northwest China, the phosphorus removal effects of concrete slag and biochar were compared in this study. Based on isothermal adsorption and kinetic adsorption experiments, two static subsurface flow constructed wetlands were constructed. Through the simulation operation, the phosphorus ($ {rm{PO}}_{rm{4}}^{{rm{3 - }}}$-P) removal effects and stability from domestic sewage by these two fillers were tested and verified by comparison. The results showed that compared with biochar, the concrete slag performed better on $ {rm{PO}}_{rm{4}}^{{rm{3 - }}}$-P adsorption with the fastest adsorption rate and the largest adsorption amount of 2.206 mg·g−1. The $ {rm{PO}}_{rm{4}}^{{rm{3 - }}}$-P adsorption by concrete slag contained both single-layer and multi-layer adsorption, indicating a non-uniform adsorption process, while the $ {rm{PO}}_{rm{4}}^{{rm{3 - }}}$-P adsorption by biochar mostly belonged to single-layer adsorption. At the average concentration of influent $ {rm{PO}}_{rm{4}}^{{rm{3 - }}}$-P with 4.6 mg·L−1, the $ {rm{PO}}_{rm{4}}^{{rm{3 - }}}$-P removal rates of concrete slag wetlands and biochar wetlands reached 94.86% and 86.37%, respectively when the hydraulic retention time (HRT) reached 24 h. By the comprehensive comparison, it is feasible to use the concrete slag as the filler for phosphorus removal by the subsurface flow constructed wetland in the northwest. The above research can provide reference for phosphorus removal material selection in constructed wetland.