Study on substrates characterization and their performance for personal care products removal from light greywater in vertical-flow constructed wetlands

Constructed wetlands (CWs) have been employed worldwide for pollutants removal from wastewaters due to their proven efficiency at different scale levels. However, there is still room for improvements, e.g., in performance, costs, sustainability and longevity. A clear understanding of the interaction between soil-plant-microorganisms and the main removal mechanisms of target pollutants within a CW could be used to improve overall removal performance. The global pollutants removal can, for example, benefit from the choice of innovative substrates, by favoring the adsorption process, offering ideal conditions for the growth of microorganisms and, thus, promoting the biodegradation process and improving assimilation of nutrients by plants. In this study, the initial characterization of different admixtures mixed with sand (mineral zeolite, and biochar produced in a circular economy perspective from plants residues and sewage-cellulose) showed that biochar provides similar cation exchange capacity (CEC) to the substrate as zeolite, which is known as CEC booster.