On-site light greywater treatment using a vertical-flow constructed wetland for the removal of personal care products and water reuse in a Luxembourgish public school

Water scarcity has currently been considered one of the main concerns due to the population growth and society development which implies an increase in potable water consumption. In Luxembourg, households are responsible for 60% of potable water consumption, with an average of 132 liters per person per day. However, from this amount, 27% is used for flushing toilets, which do not need potable water quality (AGE, 2023; VDL-Luxembourg, n.d.).
The on-site greywater treatment can be an alternative to save potable water in households by reusing the treated water for non-drinking purposes, such as toilet flushing, car washing, garden watering, and others. The greywater (GW) comprises all the wastewater produced in a household, excluding the water from toilets (blackwater-BW). The GW can be also divided into three types, light-LGW: wastewater from showers, baths and hand sinks, medium-MGW: LGW + laundries wastewater, and dark-DGW: LGW + MGW + kitchen sinks and dish washers.
However, the reuse of water requires a minimum quality according to the purposes, and this is where the on-site treatment using a vertical-flow constructed wetland (VFCWs) comes in. In previous studies, VFCWs have already proven being a promising option for macro and micropollutants removal from on-site greywater, and therefore, this technology was chosen to be tested in this study in which a pilot-scale VFCW will treat the LGW fraction from a Luxembourgish public school.
In this context, by locally treating GW, besides the possibility of removing micropollutants, such as personal care products (PCPs), at the source of pollution, at least 1/3 of potable water could be saved in households when using the treated water for flushing toilets.