Hybrid Managed Aquifer Recharge as an adaption tool to enSURE a resilient and healthy groundwater resource – MARSURE

Managed aquifer recharge (MAR), the purposeful recharge of water to aquifers for subsequent recovery, is used globally to replenish overexploited groundwater resources and prevent saltwater intrusion. Due to water shortage accelerated by climate change, there is a growing interest in using unconventional water resources for MAR, such as reclaimed water or surface water impaired by wastewater discharges. This, however, raises major concerns related to the pollution of our drinking water resources. The primary aim of MARSURE is to extend the application of MAR by combining it with pretreatment processes to prevent groundwater contamination by organic micropollutants, nutrients, metals, pathogens including antimicrobial resistant-bacteria (Hybrid-MAR). The primary output will be next-generation hybrid-MAR technologies that allow using a greater range of source water resources for MAR without compromising the quality of groundwater aquifers. Thereby, the research supports a circular water economy with more water reuse and less use of non-renewable water resources. The hybrid-MAR will provide stakeholders with documentation for the safer use of MAR as a sustainable climate change adaptation option, specifically addressing droughts, incidents expected to occur with higher frequencies and longer durations.
Scientific aims are to 1) determine the best pretreatment technologies for specific source waters focusing on ultrafiltration, ozonation, UV-based advanced oxidation processes, and powdered activated carbon; 2) define how pretreatments affect the removal of chemical and microbial pollutants in the following MAR; 3) identify means to stimulate metabolic and cometabolic degradation processes and avoid spreading of antibiotic resistance; 4) establish a model framework highlighting sites most vulnerable to droughts at the regional scale and the potential for implementing hybrid-MAR at those sites; and 5) to evaluate, through modelling, the positive effect of implementing MAR at catchment scale on the available groundwater resource.
MARSURE addresses the call (subtopic 1.2) by developing and testing new hybrid-MAR technologies to be implemented in adaptation strategies to cope with extreme droughts. The cross-European perspective is ensured by having the research centered around three joint regions, each with its characteristic climatic, geological, and hydrological conditions and different water qualities relevant for MAR: The Berlin and the Lower Franconia regions in Germany and the Motril-Salobreña region in Southern Spain. In addition, a joint field site will be established near Poitiers, France, with large-scale outdoor monolith facilities for testing developed MARSURE technologies. The broad regional approach enables us to study the potential of MAR as an adaptation measure to climate change-induced water scarcity and drought events. Thereby we can bridge the knowledge gaps in understanding how pretreatment and MAR can positively impact groundwater quantities in drought-vulnerable areas during different projected climate change scenarios (subtopic 1.1). Finally, MARSURE addresses subtopic 1.3 by including the Berlin region where the developed hybrid-MAR can be implemented, e.g., at industrial water facilities or stormwater management systems, to improve urban water infrastructure's resilience and adaptation capacity. Stakeholders involvement, including water authorities, MAR system operators, water suppliers, consultancies, legislators, environmental interest organisations, utility providers, and the scientific community in general, is of utmost importance to achieve maximal impact. These will be approached in different ways, mainly connected to biannual project meetings.