Research & reports

Irigoyen I., López M., Orden L., Moral R., Nogués I., Bustamante M.Á. · Agronomy · Europe (urban agriculture focus)

June 2025 study examining how decentralized and community composting are emerging as novel scenarios favoring localized management and valorization of organic waste streams. Supports organic waste reduction at community level and nutrient cycling for urban agriculture fertilization, offering alternatives to centralized composting.

· Turkish Journal of Agriculture - Food Science and Technology · Turkey

Produces bokashi compost by fermenting vegetable and fruit wastes with lacto serum and bran in vacuum buckets for 28 days, then characterizes the resulting compost.

Roy Hanney · Zenodo (CERN European Organization for Nuclear Research) · United Kingdom

This project report documents the development, presentation, and evaluation of "Rituals for Earthly Survival," a Butoh-inspired immersive audiovisual performance presented in Portsmouth, UK, in November 2024. It details the creative process, artistic approach, audience experience, and methodologies, including composting and collective creation, used to explore environmental crisis and renewal. The report serves as supporting documentation for ongoing creative practice research.

Medina Veliu, Hugo López-Romano, Giuseppe Picca, Marco Panettieri, Eduardo Moreno‐Jiménez, Denis Courtier‐Murias, Liliane Jean‐Soro, Johnny Gaspéri, Laura L. de Sosa · Ecotoxicology and Environmental Safety · Spain (Madrid)

This study investigated the impact of biochar-amended composts on trace element and nutrient dynamics in rooftop farming systems by cultivating tomatoes, lettuce, and Swiss chard for three years on a Madrid rooftop. Six substrates derived from spent coffee grounds, coffee silverskin, and seaweeds, with and without biochar, were used. Results showed that biochar reduced plant uptake and leaching of trace elements, lowering arsenic uptake by up to 40% in seaweed-based composts. Biochar also improved nutrient retention, reducing phosphorus and nitrogen losses by 40% and 25% respectively.

Veronika Hansen, Franziska Häfner, Bianca Messmer, Luca Bragazza, Carsten Tilbæk Petersen, Jakob Magid · Agriculture Ecosystems & Environment · Europe

Using a long-term field trial (the CRUCIAL experiment) running for more than 20 years in Denmark, this study compared the long-term effects of bio-based fertilizers (BBFs) — compost, sewage sludge, cattle slurry, and human urine — against conventional mineral NPK fertilizer on soil physical, chemical, and biological properties. Mineral NPK fertilizer supported crop productivity and improved certain soil properties but did not deliver the broader soil health benefits of organic amendments; compost and sewage sludge notably increased soil organic carbon, cation exchange capacity, porosity, water content at field capacity, and microbial activity while reducing bulk density and clay dispersibility. Human urine produced a nitrogen fertilizer effect on crop yield comparable to NPK, but showed a higher sodium adsorption ratio than NPK and a negative trend in bulk density (though values stayed below critical thresholds), indicating a need for complementary organic matter input, and carbon-rich bio-based fertilizers reduced crop production per unit of nitrogen applied.

Javier Bayo, Joaquín López-Castellanos, Marta Doval-Miñarro, Sonia Olmos · Scientific Reports · Spain

An ATR-FTIR analysis of 11 commercial compost products found microplastics in every sample, averaging 137.65 ± 6.01 items/kg dry weight and up to 631.14 mg/kg. Eco-labeled composts had significantly lower microplastic abundance, size, and concentration than non-eco products. Microplastic concentration correlated negatively with pH and nitrogen content and positively with organic matter content.

ADEME · ADEME Infos · France

One year after France's January 2024 mandate for source-separated food waste, ADEME reports that about 50% of residents (32.1 million people) now have access to municipal sorting services, 56% sort their food waste, and 9 million tonnes of biowaste per year have been diverted from incineration and landfill, backed by €100 million in green-fund investment since 2023.

Anne Lenormand · Banque des Territoires (Localtis) · France

Reporting that France's source-separation infrastructure for biowaste has tripled in three years since the January 2024 legal mandate, giving 32.1 million French residents (about 50%) access to sorting solutions (municipal collection, individual and shared composting). The rollout had a difficult start but is now accelerating, with 20 million more residents expected to gain access.

· Wikipedia (italiano) · Italy

An Italian Wikipedia article on marcite, a traditional Lombard irrigated-meadow technique combining supply and drainage channels on gently and evenly sloped land to keep grass growing through winter under a thin flowing water layer. While ordinary meadows are cut 4-5 times a year, marcite could be harvested 7 or more times, often 9, with the third cutting in late May (maggengo) alone accounting for roughly 25% of annual yield. Origins are uncertain, though Cistercian monks from France are credited with spreading the technique in northern Italy; it was largely replaced by maize cultivation in the 20th century, and today 41 marcite are protected within Parco Agricolo Sud Milano.

Juan David Arosemena Polo, Susana Toboso‐Chavero, Biraj Adhikari, Gara Villalba · Waste Management · Spain (Barcelona)

This research determined the potential of organic municipal solid waste (OMSW) compost to supply nitrogen-phosphorus-potassium (NPK) demand for urban agriculture (UA) and its environmental benefits in the Metropolitan Area of Barcelona, Spain. Using spatial material flow analysis and life cycle assessment, it was found that the current waste management system could substitute 8% of total NPK demand with compost, reduce impacts by up to 39%, and yield 130% savings in global warming. A 2025 scenario could substitute 21% of NPK demand and reduce environmental impacts by up to 1,049%.

Géant Basimine Chuma, Jean M. Mondo, Adrien Byamungu Ndeko, Etienne M. Akuzibwe, Espoir Mukengere Bagula, Gustave Nachigera Mushagalusa · Discover Sustainability · Democratic Republic of Congo (Bukavu City)

This study investigated the quantity, composition, and disposal practices of domestic waste in Bukavu City, Eastern D.R. Congo. Findings revealed significant challenges in waste management infrastructure and practices, showing that approximately 5% of waste undergoes composting, while 10% is used as livestock feed, 66% incinerated, and 17% buried. Waste management is primarily handled by children (82%), with very limited involvement from non-governmental organizations.

Jaume Vilasís Pamos, Pablo Aránguiz, Stefhania Lozano, Guillermo Palau Salvador · Revista Lecciones Vitales · Spain (Valencia)

This study examines urban agriculture initiatives in Valencia, Spain, which adopt an agroecological approach to promote sustainable practices like composting. While these collective strategies aim for sustainable agricultural models and contribute to food sovereignty, they face significant challenges, particularly regarding access to water. The initiatives also engage in political action and promote equitable organizational models.

Anne-Kristin Løes, Sebastian Eiter, Tatiana Rittl · Environmental Sciences Europe · Europe

Using soil data from ten peri-urban case farms near Oslo and Bergen, Norway, this study estimated how quickly potentially toxic element (PTE) concentrations would rise in soil under intensive application of compost or digestate from food waste, composted garden waste, or horse and poultry manure applied annually to meet a theoretical carrot crop's nitrogen, phosphorus and potassium demand. Under this intensive fertilization scenario, Norwegian soil quality limits for PTEs would be reached within 20-85 years, faster in soils with more organic matter, with limits reached first for copper and zinc, both essential micronutrients. The urban waste-based fertilizers were also found to be poorly balanced in macronutrients, with rates covering potassium demand leading to high phosphorus and nitrogen surpluses. The study concludes Norway's PTE regulations are stricter than the EU's and do not support recycling organic matter and nutrients from urban waste.

Gemma Nohales, Mike Stinavage · Zero Waste Europe · Europe

The EU mandated separate collection of bio-waste across all Member States from 31 December 2023, but a LIFE BIOBEST survey of 14 Member States found economic, legal/administrative, organisational and technical barriers present in 86-100% of sampled countries. Only 7 of 27 Member States fully met the 2020 recycling targets, and only 9 are on track for the 2025 targets.

Gabin Colombini, Fatima Senouci, Cornelia Rumpel, Sabine Houot, Philippe Biron, Axel Felbacq, Marie-France Dignac · Environmental Pollution · France

A 2024 analysis of archived soils from a long-term field experiment in France that received three urban composts — municipal solid waste compost, biowaste compost, and a sewage-sludge-plus-green-waste compost — over 21 years. Density fractionation followed by oxidation isolated 1,417 coarse microplastic (CMP) particles, identified by Py-GC/MS; different compost types produced different accumulation levels, and CMP content in soil rose over time. After 21 years the measured number of CMP particles matched estimates derived from compost inputs, but the measured mass did not for any of the three composts, which the authors attribute to biotic transport or to weathering and fragmentation making particles smaller. No difference in temporal pattern was found between films and fragments. The value of the study is long-term evidence that returning urban organic matter to soil also imports plastic; note that the site is farmland, not a city garden, so the figures cannot be transferred directly to citizen composting.

Daniel González, Raquel Barrena, Javier Moral-Vico, Ignacio Irigoyen, Antoni Sánchez · Waste Management · Spain

A 2024 study that measured methane and nitrous oxide (the main greenhouse gases), ammonia, volatile organic compounds (VOCs) and odour from several operating community composting sites in Spain treating kitchen waste, leftovers and household biowaste. Greenhouse-gas emission rates ranged from 5.3 to 815.2 mg CO₂eq per kg volatile solids per day and odour rates from 69.8 to 1,088.5 odour units on the same basis; both fell as temperature and biological activity declined with composting progress, and both were generally lower than rates reported for open-air full-scale composting plants. VOC families were most diverse in the early composting phases, while terpenes — limonene, α-pinene and β-pinene — were the most abundant throughout. The authors start from the observation that scientific data on gaseous emissions from community composting are scarce, which means that arguments about odour nuisance to neighbours have until now lacked measured reference values.

Alves, D., Villar, I., Mato, S. · Environmental Science and Pollution Research (Springer), 31(7):9873-9885 · Spain / Europe

A study comparing methodology, bulking agents, and compost quality across community composting centres (CCC) and community gardens used by local governments to treat biowaste. It shows how population density and the presence of green areas determine the siting of decentralized local composting infrastructure.

Kizza-Nkambwe S., Mpewo M., Kasima J. S., Mfuranzima K. · Sustainable Environment · Mukono, Uganda

Assesses compost quality from a waste composting facility in Mukono municipality, central Uganda, analysing physicochemical parameters and heavy metals and arsenic in mature compost.

Verónica Arcas‐Pilz, Xavier Gabarrell, Francesco Orsini, Gara Villalba · The Science of The Total Environment · Europe

A literature review mapped technologies for recovering nitrogen (N) and phosphorus (P) from urban waste sources for use in urban agriculture (UA), distinguishing (1) food, organic and biowaste sources, for which 7 recovery strategies were identified, from (2) wastewater, for which 11 were identified, and assessed the potential for the metropolitan area of Barcelona. Recovering nutrients through composting and anaerobic digestion of organic waste, composting of wastewater sludge, struvite precipitation and ion exchange in wastewater effluent could, depending on the strategy, meet current and prospective UA phosphorus demand 2.7 to 380.2 times over and nitrogen demand 1.7 to 117.5 times over. Despite this technical potential, the review concludes that current perceptions, legislation and implementation and production costs relative to existing markets do not facilitate the actual application of these nutrient recovery strategies.

Ducasse V., Capowiez Y., Peigne J. · Agronomy for Sustainable Development · France (review)

Reviews the suitability of vermicomposting the organic fraction of municipal solid waste, the quality of the resulting vermicompost, and its impact on crops and soil.

Kimo van Dijk, Lotte Veenemans, Ciska Nienhuis · · Netherlands (Amsterdam)

This report explains the importance of improving sanitation circularity, its link to circular urban food production, and the opportunities and barriers for its realization in Amsterdam. It discusses aspects related to sustainability, environment, quality, agronomy, legislation, health and safety, technology, economics, and awareness. The report provides recommendations for Amsterdam and other cities to stimulate the transition to circular sanitation and nutrient recovery/reuse in urban agriculture, including clarifying legislation and addressing barriers.

Concepción Santiago Cubas, Concepción Paredes Gil · Modern Environmental Science and Engineering · Spain

A study on Gran Canaria, Spain co-composted municipal and agricultural plant residues with three manure types — chicken, goat and cow — in an open dynamic windrow system of three trapezoidal piles (1.5 m high, 2.5 m wide, 16 m long), mixed at 37.6% straw, 32.7% manure and 29.7% pruning residue by fresh weight. Temperature, humidity and physico-chemical parameters were tracked through the process. All three piles reached the sanitation threshold required by regulation (≥60°C for at least 7 days) and produced compost suitable for agricultural use.

Danielle Purkiss, Ayşe Lisa Allison, Fabiana Lorencatto, Susan Michie, Mark Miodownik · Frontiers in Sustainability · United Kingdom

A citizen-science study invited 9,701 UK residents to test how biodegradable and compostable plastics actually degrade in home composting. Many items, including certified products, failed to fully break down; 60% of TUV OK Compost Home-certified items were still clearly visible afterward. The authors conclude home composting is not an effective or environmentally beneficial disposal method for these materials in the UK.

Miriam C. Dobson, Philip H. Warren, Jill L. Edmondson · Sustainability · United Kingdom

This nationwide citizen science project investigated resource demands of urban horticultural production in the United Kingdom using year-long diaries from 163 allotment gardeners. Findings showed an average allotment required 87 annual visits and 139 km of travel. Each kilogram of food produced used 0.4 hours of labor, 16.9 L of water, 0.2 L of topsoil, 2.2 L of manure, and 1.9 L of compost.

Felipe Parada, Mireia Ercilla‐Montserrat, Verónica Arcas‐Pilz, Elisa López‐Capél, N. Carazo, J.I. Montero, Xavier Gabarrell, Gara Villalba, Joan Rieradevall, Pere Muñoz · Journal of the Science of Food and Agriculture · Spain (Barcelona)

In spring and summer 2018, in a rooftop greenhouse near Barcelona, coir, vegetable compost from urban organic waste, perlite, and a mixture of compost and perlite substrates were evaluated over three consecutive crop cycles of lettuce. This study aimed to assess the use of substrates made from local materials as an alternative for urban agriculture during periods of water supply cuts. Results showed that compost and the mixture yielded similarly to perlite, and organic substrates increased crop resilience to water restriction.