ABSTRACT Nitrogen (N) can be recovered from different types of wastewaters. Among these wastewaters, anaerobically digested swine manure (digestate) has the highest N content in ammonia form (NH3). It is desirable to reduce N in digestate effluents to safely incorporate them in arable soil in N vulnerable zones (NVZ) and to mitigate NH3 emissions during N land application. Additional benefit is to minimize inhibition of the anaerobic process by removing NH3 during the anaerobic digestion process. This work aimed to apply the gas-permeable membrane technology to evaluate ammonia (NH3) recovery from high-ammonia digested swine manure. Anaerobically digested swine manure with NH4+ content of 4,293 mg N L−1 was reduced by 91 % (to 381 mg N L−1) during the 32-day experiment. Although the results showed a total N recovery efficiency of 71 %, it is possible to increase this recovery efficiency to > 90 % by adjusting the area of the membrane system to match the high free ammonia concentration (FA) in digested swine manure. Moreover, final digestate pH and alkalinity were kept around 8.1 and 8,923 mgCaCO3 L−1, which are convenient for the anaerobic process or incorporation in arable soil when the process is finished.

ABSTRACT In this study, eight different manure treatment plants were monitored. The plants were four on-farm and four centralized treatment plants, all of them at full-scale level. Assessment includes a total of seven pre-treatment and process units as follows: mechanical separation, with and without coagulant and flocculant addition, pasteurization, nitrification-denitrification, anaerobic digestion, and composting. The plants are located in nutrient surplus areas of three European Member States (Spain, Italy and Denmark), the majority of these areas being Nitrate Vulnerable Zones (NVZ). Results presented herein are data collected over a six-month period and comprise performance data of the treatment plants, pathogen indicators (E.coli and Salmonella) and greenhouse gas (GHG) emissions data under two scenarios: 1) the baseline scenario and 2) the treatment plant scenario. The assessment includes GHG emissions of the storage facilities, transportation, and subsequent intermediate storage, electric consumption, electric production, composting, and land application. All treatment plants studied generated a significant reduction in GHG emissions (between 53 and 90 %) in comparison to the baseline scenario. Organic matter and total solids (TS) content in manure were also greatly reduced, with values ranging between 35-53 % of chemical oxygen demand (COD) and, 24-61 % of TS for anaerobic digestion (AD) treatment plants, 77-93 % COD and 70 % TS in the case of AD combined with nitrogen (N)-removal unit plants. Nitrogen concentrations were also greatly reduced (between 65-85 %) total Kjeldahl nitrogen (TKN) and 68-83 % ammonium (NH4+-N)) in plants with N-removal units.