This work evaluates the release of phosphorus contained in the digestate from the anaerobic digestion of pig manure, through an acidification process. The objective of this acidification is to increase the amount of phosphorus available in the digestate liquid fraction and, subsequently, recover this element by chemical precipitation in the form of struvite or calcium phosphate. Two digestate samples (one fresh and one old) were studied and treated by adding various amounts of sulphuric acid to the different digestate fractions (raw digestate, solid fraction and liquid fraction). For the raw digestate, phosphorus releases higher than 95% were obtained for pH 4.0. In the last part of the experiment, the influence of acid pre-treatment on the reaction yield of phosphorus precipitation, in the form of struvite or calcium phosphate, was determined. Improvements in reaction yield were obtained up to 15% for struvite and 80% for calcium phosphate, increasing also in 7.5 times the amount of phosphorus available in the digestate liquid fraction, for both cases.
", "keywords": ["Biofertiliser", "FEASIBILITY", "NUTRIENT RECOVERY", "PH", "Struvite", "Swine", "SWINE WASTE-WATER", "0211 other engineering and technologies", "02 engineering and technology", "7. Clean energy", "01 natural sciences", "CALCIUM", "Acidification", "ANAEROBIC-DIGESTION", "Environmental Chemistry", "PHOSPHORUS REMOVAL", "Animals", "Chemical Precipitation", "Toxicology and Mutagenesis", "Anaerobiosis", "Organic waste", "SLUDGE", "0105 earth and related environmental sciences", "Phosphorus", "General Medicine", "Pollution", "6. Clean water", "Manure", "Nutrient recovery", "Health", "Earth and Environmental Sciences", "Release", "PRECIPITATION", "Waste and Biomass Management & Valorization", "CRYSTALLIZATION"]}, "links": [{"href": "https://link.springer.com/content/pdf/10.1007/s11356-020-10918-6.pdf"}, {"href": "https://doi.org/10.1007/s11356-020-10918-6"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Environmental%20Science%20and%20Pollution%20Research", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s11356-020-10918-6", "name": "item", "description": "10.1007/s11356-020-10918-6", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s11356-020-10918-6"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-10-03T00:00:00Z"}}, {"id": "10.1016/j.scitotenv.2020.143726", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-20T16:16:01Z", "type": "Journal Article", "created": "2020-11-24", "title": "A systematic comparison of commercially produced struvite: Quantities, qualities and soil-maize phosphorus availability", "description": "Production of struvite (MgNH4PO4\u00b76H2O) from waste streams is increasingly implemented to recover phosphorus (P), which is listed as a critical raw material in the European Union (EU). To facilitate EU-wide trade of P-containing secondary raw materials such as struvite, the EU issued a revised fertilizer regulation in 2019. A comprehensive overview of the supply of struvite and its quality is presently missing. This study aimed: i) to determine the current EU struvite production volumes, ii) to evaluate all legislated physicochemical characteristics and pathogen content of European struvite against newly set regulatory limits, and iii) to compare not-regulated struvite characteristics. It is estimated that in 2020, between 990 and 1250 ton P are recovered as struvite in the EU. Struvite from 24 European production plants, accounting for 30% of the 80 struvite installations worldwide was sampled. Three samples failed the physicochemical legal limits; one had a P content of <7% and three exceeded the organic carbon content of 3% dry weight (DW). Mineralogical analysis revealed that six samples had a struvite content of 80-90% DW, and 13 samples a content of >90% DW. All samples showed a heavy metal content below the legal limits. Microbiological analyses indicated that struvite may exceed certain legal limits. Differences in morphology and particle size distribution were observed for struvite sourced from digestate (rod shaped; transparent; 82 mass%\u202f<\u202f1\u202fmm), dewatering liquor (spherical; opaque; 65 mass% 1-2\u202fmm) and effluent from upflow anaerobic sludge blanket reactor processing potato wastewater (spherical; opaque; 51 mass%\u202f<\u202f1\u202fmm and 34 mass%\u202f>\u202f2\u202fmm). A uniform soil-plant P-availability pattern of 3.5-6.5\u202fmg P/L soil/d over a 28\u202fdays sampling period was observed. No differences for plant biomass yield were observed. In conclusion, the results highlight the suitability of most struvite to enter the EU fertilizer market.", "keywords": ["2. Zero hunger", "Struvite", "0211 other engineering and technologies", "Magnesium Compounds", "Phosphorus", "02 engineering and technology", "Zea mays", "01 natural sciences", "6. Clean water", "Phosphates", "12. Responsible consumption", "Chemistry", "Soil", "Bio-based fertilizers; Circular economy; Magnesium ammonium phosphate; Nutrient recovery; Phosphorus recovery; Struvite characterization; Magnesium Compounds; Phosphates; Soil; Struvite; Phosphorus; Zea mays", "Biology", "Engineering sciences. Technology", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://arpi.unipi.it/bitstream/11568/1138036/1/STOTEN_struvite.pdf"}, {"href": "https://doi.org/10.1016/j.scitotenv.2020.143726"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Science%20of%20The%20Total%20Environment", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.scitotenv.2020.143726", "name": "item", "description": "10.1016/j.scitotenv.2020.143726", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.scitotenv.2020.143726"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-02-01T00:00:00Z"}}, {"id": "10.31545/intagr/116394", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-20T16:18:54Z", "type": "Journal Article", "created": "2020-01-09", "title": "Fish pond sediment from aquaculture production \u2013 current practices and the potential for nutrient recovery**: a Review", "description": "The recent increase in fish production has resulted in the accumulation of fish pond sediment. This sediment accumulates over time and can lead to a reduction in the depth\u00a0of ponds and in the living space available for fish, it may also lead to a depletion in dissolved oxygen. Therefore, the removalof sediment from fresh water ponds is crucial for pond mainte- nance, and thus economical fish production. Fish pond sediment\u00a0is rich in nutrients and organic matter, and therefore it may have potential as a fertilizer in crop production, nursery pot culture, etc.\u00a0However, it contains compounds that undergo rapid degradation producing unpleasant odours and posing a threat to the environment, therefore it needs to be managed and handled efficiently in an environmentally sound and sustainable manner. The overall\u00a0goal of this study was to analyse the current state and management\u00a0practices of fish pond sediment generated in the existing aquaculture systems, with special reference to organic aquaculture, and\u00a0the potential for the recovery of nutrients through bioconversion processes to organic fertilizers.", "keywords": ["0301 basic medicine", "2. Zero hunger", "03 medical and health sciences", "Nutrient recovery", "13. Climate action", "Fish pond sediment", "Agriculture", "14. Life underwater", "01 natural sciences", "Intensive aquaculture", "6. Clean water", "0105 earth and related environmental sciences", "12. Responsible consumption"]}, "links": [{"href": "http://www.journalssystem.com/intagro/pdf-116394-45648?filename=Drozdz.pdf"}, {"href": "https://doi.org/10.31545/intagr/116394"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/International%20Agrophysics", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.31545/intagr/116394", "name": "item", "description": "10.31545/intagr/116394", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.31545/intagr/116394"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-01-08T00:00:00Z"}}, {"id": "10.3390/agronomy11071374", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-20T16:19:01Z", "type": "Journal Article", "created": "2021-07-07", "title": "The Potential of Digestate and the Liquid Fraction of Digestate as Chemical Fertiliser Substitutes under the RENURE Criteria", "description": "This study assessed how digestate and the liquid fraction (LF) of digestate would perform as candidate RENURE fertilisers (recovered nitrogen from manure) in nitrate vulnerable zones under the proposed criteria of the Joint Research Centre, namely, (i) a mineral nitrogen to total nitrogen ratio \uffe2\uff89\uffa5 90% (Nmin:TN \uffe2\uff89\uffa5 90%) or a total organic carbon to TN ratio \uffe2\uff89\uffa4 3 (TOC:TN \uffe2\uff89\uffa4 3); (ii) limits of \uffe2\uff89\uffa4300 copper (Cu) mg kg\uffe2\uff88\uff921 and \uffe2\uff89\uffa4800 Zinc (Zn) mg kg\uffe2\uff88\uff921. These criteria were applied to unpublished data (n = 2622) on digestate compositional properties, further amended with data from the literature (n = 180); digestate analysis from seven full-scale biogas facilities (n = 14); and biogas industry stakeholders (n = 23). The results showed that Cu and Zn mostly met the criteria, with compliance rates of 94.7% (of 1035 entries) and 95.0% (of 1038 entries), respectively. Just above 5% (of 1856 entries) met the Nmin/TN \uffe2\uff89\uffa5 90% criterion, while 36% (of 1583 entries) met the TOC/TN \uffe2\uff89\uffa4 3 criterion, while total compliance was 32% (of 1893 entries). When targeting the LF, total compliance increased noticeably, between 43 and 58% depending on DM range, indicating that LFs are better suited RENURE candidate fertilisers than unseparated digestate.
", "keywords": ["Agriculture and Food Sciences", "AMENDMENT PROPERTIES", "RENURE", "liquid fraction", "SEWAGE-SLUDGE", "NITROUS-OXIDE EMISSIONS", "ANAEROBIC CO-DIGESTION", "SAFEMANURE", "7. Clean energy", "NUTRIENT RECOVERY PROCESSES", "NUE", "USE EFFICIENCY", "BIOGAS PRODUCTION", "ORGANIC FRACTION", "S", "circular economy", "Agriculture", "04 agricultural and veterinary sciences", "6. Clean water", "Nitrates Directive", "NFRV", "MINERAL FERTILIZERS", "Earth and Environmental Sciences", "digestate", "manure", "CATTLE SLURRY", "0401 agriculture", " forestry", " and fisheries"]}, "links": [{"href": "http://www.mdpi.com/2073-4395/11/7/1374/pdf"}, {"href": "https://doi.org/10.3390/agronomy11071374"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Agronomy", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/agronomy11071374", "name": "item", "description": "10.3390/agronomy11071374", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/agronomy11071374"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-07-07T00:00:00Z"}}, {"id": "10.3390/plants10061124", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-20T16:19:09Z", "type": "Journal Article", "created": "2021-06-02", "title": "Lemna minor Cultivation for Treating Swine Manure and Providing Micronutrients for Animal Feed", "description": "The potential of Lemna minor to valorise agricultural wastewater into a protein-rich feed component to meet the growing demand for animal feed protein and reduce the excess of nutrients in certain European regions was investigated. Three pilot-scale systems were monitored for nine weeks under outdoor conditions in Flanders. The systems were fed with a mixture of the liquid fraction and the biological effluent of a swine manure treatment system diluted with rainwater in order that the weekly N and P addition was equal to the N and P removal by the system. The design tested the accumulation of elements in a continuous recirculation system. Potassium, Cl, S, Ca, and Mg were abundantly available in the swine manure wastewaters and tended to accumulate, being a possible cause of concern for long-operating recirculation systems. The harvested duckweed was characterised for its mineral composition and protein content. In animal husbandry, trace elements are specifically added to animal feed as micronutrients and, thus, feedstuffs biofortified with essential trace elements can provide added value. Duckweed grown on the tested mixture of swine manure waste streams could be considered as a source of Mn, Zn, and Fe for swine feed, while it is not a source of Cu for swine feed. Moreover, it was observed that As, Cd, and Pb content were below the limits of the feed Directive 2002/32/EC in the duckweed grown on the tested medium. Overall, these results demonstrate that duckweed can effectively remove nutrients from agriculture wastewaters in a recirculated system while producing a feed source with a protein content of 35% DM.
", "keywords": ["Agriculture and Food Sciences", "CONSTRUCTED WETLAND", "mineral supplements", "01 natural sciences", "Article", "BIOMASS", "12. Responsible consumption", "REMOVAL", "agricultural wastewater", "WASTE-WATER", "nutrient recovery", "remediation", "Lemnaceae", "ACCUMULATION", "0105 earth and related environmental sciences", "2. Zero hunger", "feed safety", "Botany", "PERFORMANCE", "6. Clean water", "NITROGEN", "PHOSPHORUS", "QK1-989", "GROWTH", "accumulation", "DUCKWEED"]}, "links": [{"href": "http://www.mdpi.com/2223-7747/10/6/1124/pdf"}, {"href": "https://doi.org/10.3390/plants10061124"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plants", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/plants10061124", "name": "item", "description": "10.3390/plants10061124", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/plants10061124"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-06-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Nutrient+recovery&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Nutrient+recovery&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Nutrient+recovery&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Nutrient+recovery&offset=5", "hreflang": "en-US"}], "numberMatched": 5, "numberReturned": 5, "distributedFeatures": [], "timeStamp": "2026-09-21T07:43:57.444182Z"}