Green walls with recycled filling media to treat greywater

The continuous growth of urban areas in the last decades has resulted in an increase in water consumption, contributing to larger volumes of urban and domestic wastewater. Thus, stakeholders have been seeking for efficient alternatives for wastewater management, namely looking for new forms of treatment and reuse. The present work provides new insights on the application of a green wall for greywater treatment, aiming at water reuse and also at contributing to Circular Economy. Two types of recycled materials, crushed tiles and textile fibers, were tested as filling media combined with two plant species. Crushed tiles were mixed with coconut fibers in a 70 %–30 % ratio and textile fibers were used as single media. The tiles+coconut mix with plants performed the best, exhibiting on average removal efficiencies >70 % for Chemical Oxygen Demand (COD) and between 59 %–70 % for Total Suspended Solids (TSS). Fibers systems had on average removal efficiencies around 60 % for COD and 50 % for TSS and clogged at the end of the study. Overall the study demonstrated that green walls for greywater treatment can contribute to circular economy through the use of recycled material as filling media.