480 / 2024-04-19 13:03:45

Enhancing Carbon Sequestration in Urban Wetlands: Assessment of the weathering potential of Filter media

Carbon sequestration,Constructed weltand,Filter media

Subtheme 5: Climate Change: Adaptation, Mitigation and Resilience > Topic 4: Carbon Peak, Carbon Neutrality under Climate Change

Sub-surface flow constructed wetland (SSF CW) is being applied to mitigate the adverse impacts of climate change. Specific wetland components, including vegetation, microorganisms, and filter media contribute to the water treatment and carbon storage function of constructed wetland systems. While filter media are considered essential components of constructed wetlands, their carbon sequestration and storage potential remain poorly understood. Therefore, this study aims to evaluate the carbon sequestration and pollutant reduction capabilities of various filter media applied in constructed wetlands. Small lab-scale SSF CW experiment will be conducted on basalt(BS), Zeolite (ZL) to examine the effects of media properties on the pollutant removal performance and carbon storage function of constructed wetlands. Total suspended solids(TSS) and heavy metals concentrations were measured for water quality. To evaluate the carbon removal rate of filter media, effluent samples were measured for total alkalinity, major cations concentrations (Na+, K+, Ca2+, Mg2+). Also, Scanning Electronic Microscope (SEM) and Energy Dispersive Spectrometer (EDS) analysis were performed to evaluate the pollutant retention and adsorption capacity of different filter media. The findings of this study can be used as a baseline for designing constructed wetlands with optimum carbon sequestration and pollutant removal performance. As result, the concentration of TSS and heavy metals in the effluent samples was significantly lower than that in the influent. Seeing atomic compositions after experiments, heavy metals that was not present before the experiment appeared in the basalt and zeolite and this change in elemental composition is the result of adsorption through ion exchange between elements. Both filter medias were efficient at removing TSS and heavy metals from influent. TSS and heavy metal concentrations in the effluent were lower in basalt compared to zeolite. basalt has a large amount of small-sized particulate matter adsorbed in the pores of the filter media. Basalt is more efficient at removing contaminants than zeolite. CaCO3 material was not generated due to carbon mineralization due to the short experimental period. But based on, TA, pH and cation release, significant silicate weathering occurred in both media. basalt is more weathered than zeolite.