Research & reports

Bruni C., Akyol Ç., Cipolletta G., Eusebi A.L., Caniani D., Masi S., Colón J., Fatone F. · Sustainability · Italy

Reviews Italian legislation and implemented projects on decentralized community composting, arguing Italy can serve as a model for Mediterranean countries building decentralized composting programs.

Ornela María Muñoz Millet, Antonio Yepes Jiménez · · Spain

A school in Spain implemented composting of organic waste from its canteen for use in an ecological school garden, with support from the AGROA school composting program and the Aguilas City Council. The entire educational community participates, from canteen staff separating waste, to the janitor transporting it, and teachers and students organizing it for compost and using it as fertilizer. This practice serves as a didactic resource for developing environmental attitudes and sustainable habits.

Madeleyne Ivonne Demera-Pico, Carlos Francisco Ortega-Ordóñez · Dialnet (Universidad de la Rioja) · Spain

A study reporting the incorporation of substrate into an ecological garden while applying strategies for organic production. Solid waste was sorted and organic waste used to develop three types of compost: the first from humus-rich soil with 10% sandy soil, the second from silty soil with 20% sandy soil, and the third from silty soil with 40% sandy soil, aimed at improving water filtration and moisture retention. Each compost was combined with production strategies using biostimulants and ecological micro- and macronutrients, and irrigation water was monitored for chlorine concentration and pH before use. The compost made from silty soil with 40% sandy soil, combined with 5 mL of a biostimulant that adjusted alkaline water to neutral pH, produced the greatest increase in soil fertility and the best improvement in germination, cultivation, and post-harvest development.

Arne Backlund, Annette Holtze · Linnaeus Eco-Tech · Europe

A report on one of several wastewater projects run since 1998 by Storstrøm County and A & B Backlund ApS in Denmark, examining source-separating (diverting) toilet technology and the composition of collected human urine mixture and composted faeces, carried out under an Action Plan administered by the Danish Environmental Protection Agency. User experience in the Danish projects shows the diverting technology is accepted in housing areas, works well in public places, and is highly appreciated in allotment gardens, though further technical improvement is still needed. Comparing the collected urine mixture's nutrient, heavy-metal, organic-compound and microorganism content against organic fertilizers used in Danish agriculture, the analyzed urine mixture was found to be of high quality.

Burghardt W., Schneider T. · Journal of Soils and Sediments · Germany (Ruhr)

Analysed pH, bulk density, and contents/stocks of organic carbon, nitrogen and heavy metals (Pb, Cd, Zn, Cu, Ni) in vegetable patches, lawns and compost heaps across fourteen gardens in four allotments of the northwestern Ruhr area.

Burghardt W., Heintz D., Hocke N. · Eurasian Soil Science · Germany (Ruhr)

Compared vegetable-garden soils with surrounding arable land in the central Ruhr area, analysing horizons, texture, pH, bulk density, C/N ratio, and stocks of organic carbon, nitrogen and available nutrients.

Marta Bożym · Ochrona Środowiska i Zasobów Naturalnych · Poland

A study measuring heavy-metal content (cadmium, lead, copper, zinc, nickel, chromium) in compost and resident earthworms sampled from home composters and allotment gardens in the Opole region of Poland. The compost samples themselves were not contaminated with heavy metals and stayed within Polish legal limits for solid organic fertilizers. However, metal accumulation in earthworms varied by metal: the bioaccumulation factor (BAF) was high for cadmium, lead and zinc, while no accumulation was found for nickel, chromium or copper. The authors conclude that earthworm species native to Poland, such as Eisenia fetida, can serve as potential bioindicators of metals in the environment.

Rosanne Wielemaker, Jan Weijma, G. Zeeman · Resources Conservation and Recycling · Netherlands (Rotterdam)

This paper assesses the match between supply from New Sanitation (NS) systems and demand from Urban Agriculture (UA) for nitrogen, phosphorus, and organic matter in Rotterdam. Using the Urban Harvest Approach, the research found that UA's demand for nutrients and organic matter can be minimized by 65–85%, achieving 100% self-sufficiency for phosphorus and partial self-sufficiency for nitrogen and organic matter. The integration of NS and UA maximizes urban self-sufficiency.

Baptiste Grard, N. Bel, Marchal, Nicolas, Frédéric Madre, Jean‐François Castell, Philippe Cambier, Sabine Houot, Nastaran Manouchehri, Stéphane Besançon, Jean‐Charles Michel, Claire Chenu, Nathalie Frascaria‐Lacoste, Christine Aubry · Kobra (Universitätsbibliothek Kassel) · France (Paris)

A 2012 pilot experiment in Paris, France, tested simple rooftop gardening systems using local urban organic waste as crop substrates. Measurements of production levels and heavy metal content in crops and substrates showed high crop production with limited inputs, low heavy metal pollutants in edible parts, and positive yield influence from layered substrates and earthworm inoculation. These results suggest rooftop gardening is feasible and has potential for urban resiliency, though further assessment of roof types, pollution levels, and sustainability is needed.

Emmanuelle Vaudour, Christine Aubry, Liliane Bel, Laëtitia Bréchet, Philippe Cambier, Yves Coquet, Karim Dhaouadi, Veronique V. Etievant, Benoît Gabrielle, Jean-Marc J.-M. Gilliot, Jean Christophe Gueudet, Dalila Hadjar, Jonas Hamiache, Sabine Houot, Christophe Labat, Patricia Laville, Raia Silvia Massad, Joël Michelin, Paul Emile Noirot Cosson, Jean-Noël Rampon · HAL (Le Centre pour la Communication Scientifique Directe) · France

The PROSTOCK project aimed to spatially assess the potential of recycling organic waste (exogenous organic matter, EOM) to improve soil organic carbon stocks (SCS) in peri-urban agricultural areas. It also evaluated the impacts of EOM use on greenhouse gas emissions and nitrate leaching. The Versailles Plain and Alluets Plateau (221 km²) were chosen as the study region, with field and lab measurements collected from over 250 point locations. The project advanced the use of imaging data for estimating topsoil organic carbon content (SOC) from soil reflectance spectra, but found that medium spatial resolution multispectral satellite images do not discriminate changes in SOC resulting from EOM applications.

Javier Varona Espallargas · RECAM Metropolitan Knowledge Repository · Spain (Barcelona)

This study analyzes community self-composting at the L'Hortet del Forat urban community garden in Barcelona, Spain. It aims to assess the potential for waste prevention and management, and to identify the social characteristics of users engaging in this practice.

Steffen Lehmann · Journal of Green Building · Europe

This paper discusses resource recovery and materials flow in cities, noting that urban farming has emerged as a valid urban design strategy in Europe, contributing to local food production, organic waste composting, and biodiversity. It reports on best practices for implementing zero waste, including adaptive re-use and design for disassembly, and identifies that the construction and demolition sector is a major waste producer. A key finding is that achieving 'zero-waste' requires strong industry leadership, new policies, effective education, and refocused research agendas.

European Commission · European Commission — Directorate-General for Environment · Europe

This European Commission page on the Waste Framework Directive states the directive entered into force on 12 December 2008. It notes the EU generates around 2.5 billion tonnes of waste per year (roughly 5 tonnes per person annually). An amended version, effective 16 October 2025, includes food-waste reduction targets.