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 These criteria were applied to unpublished data (n = 2622) on digestate compositional properties, further amended with data from the literature (n = 180); digestate analysis from seven full-scale biogas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/en14123488", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-04T16:21:19Z", "type": "Journal Article", "created": "2021-06-11", "title": "Bio\u2010crude production through recycling of pretreated aqueous phase via activated carbon", "description": "The management and optimization of the aqueous phase are the major challenges that hinder the promotion of hydrothermal liquefaction (HTL) technology on a commercial scale. Recently, many studies reported about the accumulation of the N-content in the bio-crude with continuous recycling of the aqueous phase from high protein-containing biomass. In the present study, sewage sludge was processed at 350 \uffc2\uffb0C in an autoclave. The produced aqueous phase was treated with activated carbon, and its subsequent recycling effect on the properties of the bio-crude and aqueous phase was investigated. By contacting the aqueous phase with activated carbon, 38\uffe2\uff80\uff9343% of the total nitrogen was removed from the aqueous phase. After applying the treated aqueous phase recycling, the energy recovery of the bio-crude increased from 50 to 61% after three rounds of recycling. From overall carbon/nitrogen recoveries, 50 to 56% of the carbon was transferred to the bio-crude phase and more than 50% of the nitrogen remained in the aqueous phase. The aqueous phase contained mostly of N&O-heterocyclic compounds, small chain organic acids, and amides. ICP-AES analysis showed that more than 80% of the inorganic elements were concentrated into the solid phase.
", "keywords": ["Technology", "sewage sludge", "Activated carbon", "Aqueous phase recycling", "T", "Bio\u2010crude", "0211 other engineering and technologies", "02 engineering and technology", "6. Clean water", "12. Responsible consumption", "aqueous phase recycling", "HTL", "13. Climate action", "0202 electrical engineering", " electronic engineering", " information engineering", "activated carbon", "Sewage sludge", "bio-crude", "aqueous phase recycling; sewage sludge; activated carbon; HTL; bio-crude"]}, "links": [{"href": "http://www.mdpi.com/1996-1073/14/12/3488/pdf"}, {"href": "https://www.mdpi.com/1996-1073/14/12/3488/pdf"}, {"href": "https://doi.org/10.3390/en14123488"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Energies", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/en14123488", "name": "item", "description": "10.3390/en14123488", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/en14123488"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-06-11T00:00:00Z"}}, {"id": "10.3390/pr9030491", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-04T16:21:28Z", "type": "Journal Article", "created": "2021-03-09", "title": "Sequential Hydrothermal Processing of Sewage Sludge to Produce Low Nitrogen Biocrude", "description": "A hydrothermal pre-treatment has been developed to improve sewage sludge quality or to produce low nitrogen biocrude via hydrothermal liquefaction (HTL) in a subsequent step. The mild hydrothermal pre-treatment (150 \uffc2\uffb0C) step was performed with deionized water, sulfuric acid (0.5 M), or citric acid (0.5 M) to solubilize nitrogen containing compounds in the aqueous supernatant. Downstream, the residual solid material was liquefied with the addition of sodium carbonate via hydrothermal liquefaction (350 \uffc2\uffb0C). The pre-treatment with citric acid transferred up to 66.7 wt. % of nitrogen into the aqueous supernatant, while 62.0 wt. % of carbon was recovered in the solid. Due to the pre-treatment lipids retained in the sewage sludge solid, which increased the favored biocrude yield up to 42.9 wt. % and the quality evaluating value H/Ceff ratio significantly to 1.48. Multi-method characterization of the resulted biocrude samples showed a lower concentration of N-heterocycles, while long-chain aliphatics and free fatty acid are increased.
", "keywords": ["Technology", "ddc:600", "sewage sludge", "nitrogen extraction", "info:eu-repo/classification/ddc/600", "600", "sequential hydrothermal liquefaction", "hydrothermal hydrolysis", "pre-treatment", "6. Clean water", "12. Responsible consumption"]}, "links": [{"href": "http://www.mdpi.com/2227-9717/9/3/491/pdf"}, {"href": "https://www.mdpi.com/2227-9717/9/3/491/pdf"}, {"href": "https://doi.org/10.3390/pr9030491"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Processes", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/pr9030491", "name": "item", "description": "10.3390/pr9030491", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/pr9030491"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-03-09T00:00:00Z"}}, {"id": "10044/1/108326", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-04T16:24:59Z", "type": "Journal Article", "created": "2023-11-30", "title": "Do contaminants compromise the use of recycled nutrients in organic agriculture? A review and synthesis of current knowledge on contaminant concentrations, fate in the environment and risk assessment", "description": "Use of nutrients recycled from societal waste streams in agriculture is part of the circular economy, and in line with organic farming principles. Nevertheless, diverse contaminants in waste streams create doubts among organic farmers about potential risks for soil health. Here, we gather the current knowledge on contaminant levels in waste streams and recycled nutrient sources, and discuss associated risks. For potentially toxic elements (PTEs), the input of zinc (Zn) and copper (Cu) from mineral feed supplements remains of concern, while concentrations of PTEs in many waste streams have decreased substantially in Europe. The same applies to organic contaminants, although new chemical groups such as flame retardants are of emerging concern and globally contamination levels differ strongly. Compared to inorganic fertilizers, application of organic fertilizers derived from human or animal feces is associated with an increased risk for environmental dissemination of antibiotic resistance. The risk depends on the quality of the organic fertilizers, which varies between geographical regions, but farmland application of sewage sludge appears to be a safe practice as shown by some studies (e.g. from Sweden). Microplastic concentrations in agricultural soils show a wide spread and our understanding of its toxicity is limited, hampering a sound risk assessment. Methods for assessing public health risks for organic contaminants must include emerging contaminants and potential interactions of multiple compounds. Evidence from long-term field experiments suggests that soils may be more resilient and capable to degrade or stabilize pollutants than often assumed. In view of the need to source nutrients for expanding areas under organic farming, we discuss inputs originating from conventional farms vs. non-agricultural (i.e. societal) inputs. Closing nutrient cycles between agriculture and society is feasible in many cases, without being compromised by contaminants, and should be enhanced, aided by improved source control, waste treatment and sound risk assessments.", "keywords": ["Organic farming", "SEWAGE-SLUDGE", "LONG-TERM IMPACT", "PATHOGENIC BACTERIA", "Environmental Sciences & Ecology", "Risk Assessment", "630", "Societal wastes", "12. Responsible consumption", "Organic contaminants", "Soil", "PRE-APPLICATION TREATMENT", "HEAVY-METALS", "ANAEROBIC-DIGESTION", "11. Sustainability", "Animals", "Humans", "Soil Pollutants", "Fertilizers", "Risk assessment", "2. Zero hunger", "Organic Agriculture", "Science & Technology", "Sewage", "ANTIBIOTIC-RESISTANCE GENES", "FERTILIZER VALUE", "SOIL DYNAMICS", "Agriculture", "Nutrients", "15. Life on land", "6. Clean water", "13. Climate action", "BACTERIAL COMMUNITIES", "Life Sciences & Biomedicine", "Plastics", "Environmental Sciences"]}, "links": [{"href": "https://doi.org/10044/1/108326"}, {"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": "10044/1/108326", "name": "item", "description": "10044/1/108326", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10044/1/108326"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-02-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?facets=true&soil_management=sewage+sludge&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?facets=true&soil_management=sewage+sludge&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?facets=true&soil_management=sewage+sludge&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?facets=true&soil_management=sewage+sludge&offset=10", "hreflang": "en-US"}], "numberMatched": 10, "numberReturned": 10, "distributedFeatures": [], "timeStamp": "2026-04-04T17:53:28.623502Z"}