School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, New South Wales 2480, Australia.
Environ Sci Technol. 2011 Jul 1;45(13):5746-53. doi: 10.1021/es200934y. Epub 2011 Jun 3.
In this study, Bauxsol pellets packed in PVC columns were used to remove nutrients and trace-metals from municipal wastewater during a 6 months field trial. Bauxsol pellet columns showed a high phosphate removal rate via precipitation of PO(4)(3-) with Ca(2+) and Mg(2+) ions: at 90% in the 1st month; at 80% from the second to fifth months; and at 60% in the sixth month. Pellet bound total phosphorus and Colwell phosphorus were 7.3 g/kg and 2 g/kg and are about 20 times the concentrations found in most fertile soils. Trace-metals in effluents were bound, probably irreversibly under the columns' environmental conditions, to the Bauxsol minerals that have high surface area to volume ratios and high charge to mass ratios. Experimental results showed a complex nitrogen cycle operating within the Bauxsol pellet columns including anoxic nitrification, denitrification, and anammox processes. Although a transient pH spike, associated with the release of unreacted CaO from the cement binder used in the pellets, was observed, this may be readily corrected through post-treatment pH adjustment. Hence, the geochemistry of Bauxsol pellets can effectively remove and bind nutrients and trace-metals during wastewater treatment, and further research may show that saturated spent pellets can be used as fertilizer.
在这项研究中，Bauxsol 球粒在 PVC 柱中用于去除市政污水中的营养物质和痕量金属，进行了为期 6 个月的野外试验。Bauxsol 球粒通过与 Ca(2+)和 Mg(2+)离子沉淀 PO(4)(3-)表现出高磷酸盐去除率：第 1 个月为 90%；第 2 至第 5 个月为 80%；第 6 个月为 60%。球粒结合总磷和 Colwell 磷分别为 7.3 g/kg 和 2 g/kg，大约是大多数肥沃土壤中浓度的 20 倍。废水中的痕量金属在柱环境条件下，可能不可逆地结合到 Bauxsol 矿物上，这些矿物具有高的表面积与体积比和高的电荷与质量比。实验结果表明，Bauxsol 球粒柱内存在复杂的氮循环，包括缺氧硝化、反硝化和厌氧氨氧化过程。尽管观察到与球粒中使用的水泥粘合剂中未反应的 CaO 释放相关的瞬时 pH 峰值，但通过后处理 pH 调整很容易进行校正。因此，Bauxsol 球粒的地球化学可以有效地去除和结合污水中的营养物质和痕量金属，进一步的研究可能表明，饱和的废球粒可以用作肥料。
