TOPIC 4: Compost to reduce emissions and get fertile soils

TOPIC 4: Compost to reduce emissions and get fertile soils

In this topic you get more information about the situation of organic waste in residual waste and why it is important to compost it.


Composting food waste reduces waste from landfills, thus helping to abate global emissions of greenhouse gasses, e.g. methane gas, that is one of the most climate-impacting pollutants and contributes significantly to climate change. At the same time, it produces useful peat-free fertiliser that improves plant growth and soil structure. Currently, household kitchen waste is the biggest fraction (88 %) of bio-waste that EU citizens struggle to sort properly for separate collection and high-quality recycling. EU-Member states are obliged to reduce the amount of biodegradable municipal waste down to 10% in 2035.  But we don’t have to wait for policies – we can start composting right away! Composting within the neighbourhood  is a simple and inexpensive solution that cities can use as a tool to reduce emissions in waste treatment as well as transport. Composting in community gardens or community composting in general is a great way enabling people to reflect about their waste management, material cycles and their impact on climate in general. On the other side valuable fertilizer can be produced within the neighbourhood and does not need to be bought in stores. Important to know is that the (mainly carbon based) delivery logistics of items like soil, compost and fertilizer and it’s production, have a great impact on the CO2 balance of the produced vegetables. That’s why the supposedly climate-friendly, locally produced vegetables can have a poor overall carbon footprint via the purchase of fertilizer, compost and different substrates. If soil substrates are purchased, compost substrates are in any case preferable to peat products as they are many times less harmful to the climate. Regarding composting many varieties have been developed to transform organic waste to compost, which assists with the hummus build up. From indoor composting through worm compost & bokashi up to classic hot-rotting composting in chambers and rotation composter. 


A general advice for climate-friendly composting is to look after the carbon/ nitrogen ratio. Fruits/vegetables tend to have more nitrogen where leaves, and weeds have more carbon. If there is less carbon in the compost material composting tends to become anaerobic and produce a foul smell and the release of methane gas. 


ECN-Guidance on Seperate Collection 1/22

EU Circular Economy Package 2018

Essbare Seestadt Endbericht 2021,P.94