Welcome to Project GROW

To move towards a sustainable, resilient water system, water reuse and the recycling of treated wastewater are essential. The main barriers to the reuse of treated wastewater are a lack of knowledge about its environmental impacts and uncertainty about public perception and acceptance.

The GROW project is an interdisciplinary field experiment investigating these barriers by using treated municipal wastewater for groundwater recharge through subirrigation. The project aims to determine whether the use of treated wastewater for irrigation and artificial recharge is acceptable from an environmental and consumer perspective.

,

  • Groundwater quality

    We closely monitor the impact of subirrigation with treated wastewater on groundwater quality on and around the field. We take monthly samples of effluent, groundwater and surface water and analyze general physicochemical parameters, nutrients, organic pollutants and trace metals to assess if the use of treated wastewater for irrigation and recharge is acceptable from an environmental.

  • Public perception

    We analyze perceptions about re-use of treated wastewaster and understand how they relate to social and personal attitudes. We aim to understand how the scientific data can be framed to support decisions making and develop effective communication strategies to address perceptions and sentiments on re-use of treated wastewater.

  • Aquifer recharge

    We evaluate the year-round operation of a subirrigation system as a way to improve groundwater levels and crop resilience against droughts. We observe groundwater levels and groundwater fluxes on and around the field to assess the impact on the groundwater system in space and time. We seek to identify the most accurate model simulating the impact of subirrigation on the aquifer and crops.

Experimental subirrigation site

In our experiment pilot site in Kinrooi (east of Flanders), we installed a subirrigation system consisting a of network of pipes directly connected to the adjacent domestic wastewater treatment plant. Subirrigation is a method of watering crops from below the soil surface, close to the plants root zone. Before we began subirrigation in April 2022, all treated wastewater was discharged to the nearby Abeek river, swiftly flowing to the sea. Now, a portion of that water is routed through two large buffer tanks and supplied at a controlled rate into the subirrigation system. As the water infiltrates the ground, some of it is directly used by the crops and some percolates to the water table.

Impacts on water groundwater quantity and quality are closely monitored in a network of over 20 piezometer on and around the field.

Alternative source of water

In 2022, the domestic wasterwater treatment plant in Kinrooi alone discharged more than 700,000 m³ of water to Abeek. To put this in perspective, this is sufficient to irrigate 140 hectars of maize throughout its entire growth season or supply enough drinking water to roughly 19,000 people in Belgium for the whole year. There are nearly 400 treatment plants in Belgium. There is a huge potential for increase re-use of treated wastewater to reduce our reliance on groundwater for both domestic and agricultural needs which often endangers ecosystems that depend on these water reserves.

It is time we challenge the notion that wastewater is simply waste. Instead, we must view it as a valuable resource that we cannot afford to waste. We need a paradigm shift in our relationship with water to one where every drop counts.