Potential and risks of water reuse in Brandenburg (Germany) - an interdisciplinary case study

For Brandenburg, a region in Germany with increasing water shortage and drought events, water reuse can counteract competition scenarios between drinking water supply, agricultural irrigation, and industrial use. Centralized and decentralized sources for reclaimed water are found to potentially substitute 245 or 28% of irrigation water, respectively, in agriculture production in Brandenburg. For such a reuse scenario, the fate of organic micro-pollutants is examined for diatrizoate (DZA) and carbamazepine (CBZ). Retention in local sandy soil and transfer into roots and leaves of arugula are analyzed in lysimeter studies and greenhouse pot experiments. Vertical transport was found for DZA and accumulation in or on arugula roots with a root concentration factor of 1,925 +/- 34% but a low bioconcentration factor due to intrinsic molecule properties. CBZ was not found to be mobile in the sandy soil but accumulates in arugula roots and leaves by factors of 70 +/- 7% and 155 +/- 12%, respectively. Further research on potential plant uptake and groundwater enrichment for more substances is highly recommended as well as tertiary wastewater treatment prior to water reuse. HIGHLIGHTS center dot The volume of treated wastewater exceeds irrigation water by a factor of 2.5 in Brandenburg. center dot Water reuse could reduce competition between drinking water supply in the industry and agriculture. center dot Organic micro-pollutant pathways for sandy soil to groundwater and to plants are assessed. center dot Carbamazepine did not reach 10 cm depth in lysimeter studies probably due to acidic soil pH. center dot Diatrizoate obtained very high concentrations in arugula roots but were low in leaves.