Animal manure derivatives as alternatives for synthetic nitrogen fertilizers

Intensification of livestock production in combination with a decline in arable land has resulted in a discrepancy between excess load of nutrients from livestock production and the possibility to apply these nutrients in an environmental way on agricultural land. Consequently, the mineral input and output in livestock intensive regions is not balanced. The crop production systems rely on synthetic fertilizers for fertilization, whereas livestock production systems face problems in manure disposal. This dissertation aimed towards efficient use of resources by re-connecting crop and livestock production through animal manure processing. The processing results in animal manure derivatives such as liquid fraction (LF) of digestate, mineral concentrate and air scrubber water, that might have potential to be used as alternatives for synthetic nitrogen (N) fertilizers. The dissertation investigated N fertilizer performance of these materials with regard to crop yield and soil properties on laboratory, greenhouse and field scale. Results showed that LF of digestate, air scrubber water and mineral concentrate can be used as synthetic N fertilizer substitutes without adverse effects on crop yield. With regard to environmental aspects, it seems that these materials should not additionally increase the risk of nitrate leaching as compared to conventional fertilization practices. Some of their characteristics (e.g. form, nutrient concentration, stability) differ from the characteristics of synthetic N fertilizers, however their N performance indicates the potential of labelling LF of digestate, ASW and mineral concentrate as processed mineral fertilizers on European fertilizer market

Assessment of tailor made blends of recycling derived fertilizers in pot cultivation of Spinacea oleracea

The intensive plant production in Europe has resulted in an increasing demand for fertilizers. Due to the imbalance in the distribution of agricultural nutrients arising from various biomass sources, there is still a large dependence on synthetic mineral fertilizers. An appealing option is to process these biomass streams into recycling-derived fertilizers (RDFs). However, these RDFs have a high degree of nutrient variability which influences the farmers’ willingness to use them. The Interreg NWE ReNu2Farm project envisages a solution to this problem by creating tailor-made blends with desirable nutrient ratios aligned with specific crop requirements. These blends are created with the vision of replacing synthetic mineral fertilizers in the long-term. As a first step toward achieving this goal, twenty-one RDFs including ashes, struvite, compost, digestate derivatives, ammonium sulphate, ammonium nitrate, ammonia water, pig urine and mineral concentrate from the three major biomass streams, i.e. animal manure, sewage sludge, and food waste have been characterized. Using these results, two blends were prepared based on the optimal NPK ratios as required for pot cultivation of spinach (Spinacea olaracea L.). The two prepared blends consisted of i) ammonium nitrate mixed with concentrate after evaporation of liquid fraction of digestate, and ii) ammonia water mixed with concentrate after evaporation of liquid fraction of digestate. The fertilizer performance of these blends will be compared to an unfertilized control, synthetic fertilizers and individual performance of ammonia water, ammonium nitrate and concentrate after evaporation of liquid fraction of digestate. The fertilizers will be applied in two dosages, optimal and optimal minus 50%, resulting in thirteen treatments with four replicates. After the harvest of spinach, the plant material and soil will be analyzed to evaluate the nutrient uptake and nutrient use efficiency (NUE) of the tailor-made blended fertilizers. Nitrogen incubation experiments will also be carried out in parallel with the pot experiment to determine the nitrogen dynamics of the applied fertilizers relative to the dynamics of synthetic N fertilizers. Acknowledgement: The research is done as a part of the ReNu2Farm project that receives funding from the Interreg North-West Europe Programme under Grant Agreement no. NWE601. See http://www.nweurope.eu/projects/project-search/renu2farm-nutrient-recycling-from-pilot-production-to-farms-and-fields/ and https://www.biorefine.eu/projects/renu2farm for more information

Assessment of recycling-derived fertilizers and tailor-made blends in laboratory and field

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SYSTEMIC : nutrient recovery from anaerobic digestate of biowaste : technical assessment of full scale installations throughout Europe

Biowaste (i.e. animal manure, sewage sludge, food and feed waste) is the most abundant waste stream in Europe and hence has been identified as a prominent potential resource for the production of biogas. During biogas production also a nutrient rich residue, called digestate, is produced. Treatment of digestate for the recovery of mineral nutrients such as nitrogen (N), phosphorus (P) and potassium (K) has been developed and tested in pilot facilities. Still, the implementation at large scale needs to be consolidated. SYSTEMIC, Horizon 2020 project, aims to demonstrate that the combination of anaerobic digestion (AD) and nutrient recovery and reuse (NRR) forms a prerequisite for the valorization of biowaste in an economically viable manner. This will be demonstrated by i) selecting the most promising NRR technologies and ii) implementing selected NRR technologies via full-scale investments on five state-of-the-art AD plants: Groot Zevert (the Netherlands), AMPower (Belgium), Acqua & Sole (Italy), Fridays (UK) and Benas (Germany). At Groot Zevert, P will be recovered from the solid fraction of pig manure as a calcium phosphate by means of an innovative new P stripping technology. N will be recovered from the liquid fraction of pig manure by means of an advanced membrane separation system. AMPower will implement a vaporizer and reverse osmosis system for the production of mineral concentrates from food wastes. Acqua & Sole will install a novel N recovery absorber which enables them to recover N in a mineral form and reduce the N content of the organic fraction. Fridays will be equipped with a fully integrated AD and NRR system based on an advanced second-stage mesophilic digester which allows a better control of the pH during the digestion process, resulting in a higher N recovery from the digestate. GNS will optimize and demonstrate its novel ammonia recovery unit by providing technical and economic data on the performance of the full-scale and pilot scale NRR technologies. As a first step in Systemic demonstration, technical assessment of the five AD plants was conducted by monitoring principal flows. The performances of different NRR technologies were evaluated in terms of removal of N, P, K and other macro- and micronutrients. The energy requirements of each process unit were assessed. The analyzed technologies demonstrated to be valuable candidates for NRR from digestate. This research is conducted in frame of the European project H2020-SYSTEMIC – see www.biorefine.eu/projects/systemic for more information