Five light-weight aggregates (LWAs), suitable for filter media in subsurface flow constructed wetlands, were tested for potential removal of phosphorus (P). P-sorption variation is dependent on the chemical characteristics of the LWA. All LWAs exhibited high pH and high total metal content; however, P-sorption capacity varied by two orders of magnitude. Of the LWAs' chemical characteristics (total metal content, cation exchange capacity, and oxalate soluble Fe and Al), total metal content has the closest relationship with the P-sorption capacity. Among the four major metal ions (Mg, Ca, Fe and Al), Ca has the strongest correlation with the P-sorption capacity.
Phosphorus sorption and chemical characteristics of lightweight aggregates (LWA)-potential filter media in treatment wetlands
T. Zhu, P. D. Jenssen, T. Mæhlum, T. Krogstad; Phosphorus sorption and chemical characteristics of lightweight aggregates (LWA)-potential filter media in treatment wetlands. Water Sci Technol 1 March 1997; 35 (5): 103–108. doi: https://doi.org/10.2166/wst.1997.0175
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