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The escalating demand for innovative solutions is driven by the challenges posed by water quality degradation and the pervasive impacts of climate change. As such, this study evaluated the performance of filter media to mitigate these challenges through multi-functional applications in urban constructed wetlands (UCWs). Column testing of organic filter media, including biochar (BC), woodchip (WC), anthracite (AT), and activated carbon (AC), as well as inorganic filter media, such as ceramic balls (CB), basalt (BS), and porous sand (PS), with synthetic stormwater runoff influent was conducted to assess their performance through water quality parameters and Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) analysis for carbon storage potential. Among the media tested, AC exhibited high pollutant removal efficiencies amounting to 84%, 54%, 56%, and 44% for total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP), respectively. For inorganic media, PS had the highest TSS and TN removal, whereas BS exhibited the highest COD and TP removal. Overall performance rating revealed that AC and BS, despite their efficient pollutant removal, are associated with higher costs, resulting in a lower ranking compared to AT and PS. SEM-EDX analysis identified PS and AC as standout media for potential carbon storage, attributed to their extensive surface areas and pore structures providing abundant adsorption sites. The results from this study highlighted the potential applications of various filter media in UCW designs with the aim of achieving carbon neutrality and sustainable urban development. [ABSTRACT FROM AUTHOR]

For determining the accumulated pollutant mass on highways, two years of monitoring data were used from eight highway sites in southern California. Buildup over antecedent dry days was calculated from mass washed off from the following storm and retained pollutant mass. Mass accumulation rates were determined for total suspended solids (TSS), chemical oxygen demand (COD), oil and grease, total Kjeldahl nitrogen, and total phosphorus, and are reported in g/[m.sup.2]-day. A revised buildup model is proposed using an alternative modeling approach to describe buildup during dry days between storms. The result shows that, between 1 and 10 antecedent dry days, the pollutant mass buildup rates are determined to be 0.544 g/[m.sup.2]-day for TSS, 0.114 g/[m.sup.2]-day for COD, and 0.0113 g/[m.sup.2]-day for oil and grease. Buildup rates decline in subsequent periods rates decreased by 79% for TSS, 78% for COD, and 61% less for oil and grease in the following 10-70 day period. DOI: 10.1061/(ASCE)0733-9372(2006)132:9(985) CE Database subject headings: Stormwater management; Pollutants; Highways: Runoff; California.