| Summary: | Intensive pig farming produces huge amounts of swine manure, which can cause regional nutrient imbalances and represent a potential source of soil and water pollution due to manure over-application. In order to improve nutrient stewardship, technologies for manure treatment and selective recovery of nutrients (especially ammonia) have to be developed to foster agriculture–food system sustainability. In the present study, a combined stripping and ion exchange process using natural zeolite (ion-exchanger-loop-stripping process) is tested for nitrogen recovery from swine manure to determine its technical feasibility in this novel field of application. Ammonium removal rates of 85 to 96% were achieved in pilot scale experiments with preprocessed manure (~500 L h<sup>−1</sup> after mechanical filtration; input concentration: ~1.3 g NH<sub>4</sub><sup>+</sup> L<sup>−1</sup>). NH<sub>4</sub><sup>+</sup> was successfully transferred to a concentrated ammonium sulfate solution (final concentration: 66 g NH<sub>4</sub><sup>+</sup> L<sup>−1</sup>), with no significant transfer of other manure components. Hence, various utilizations of the product solution are possible, e.g., for industrial off-gas cleaning (DeNOx) or as raw material for fertilizer production. Based on these findings, the ILS-process can be regarded as a promising option for nitrogen recovery from swine manure.
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