Composting: a step towards a circular economy within everyone's reach!

by | 16 Jan, 2020 | Compost, Ecology, Science

50% of our waste is compostable! It is important to compost this waste because it is the only technique that does not generate substances other than those inherent to life and usable by the plant world. In this respect, it is essential to compost at home and not in communal facilities, because "bin liners, collection, transport, incineration and landfill generate environmental (and financial) costs that can be significant". This is not us saying this (although we agree 100%!), it is Wallonia environment as well as many scientific studies (such as the one carried out by the DTU in Denmark or the one by the University of Barcelona). We must therefore prevent our organic waste from leaving its place of birth (i.e. mainly our kitchens and gardens). To do this, there is nothing like individual or neighbourhood composting. In addition, numerous studies and field experiments (see here) inform us that spreading our compost on the soil increases its ability to store carbon from the air and retain water. Taking all this into account, DTU researchers estimate that one tonne of composted organic waste reduces greenhouse gases by 35 kg CO2 equivalent[1]. This is about the same as a tree does in a year! In addition to this already very satisfying impact, composting also increases the diversity of fauna and flora. Composting therefore provides real benefits and has an important impact on our future! However, according to a recent study by Wallonia environment47% of Walloons do not compost their organic waste. The main difficulties that we, the citizens, mention to justify this disastrous figure are :
  • Lack of access to compost. Indeed, 48% of people living in urban areas do not have access to a compost bin. This is huge!
  • Lack of know-how (14%). It is true that composting is not easy. However, it is all the more rewarding if the compost obtained is of good quality: it is important to avoid the release of odours and the production of toxic compounds.
  • The source of nuisance that compost represents (13%). It is true that organic waste tends to give off bad smells and attract unpleasant visitors to the kitchen...
  • Lack of time (12%). Indeed, in addition to requiring considerable know-how, good composting requires sustained attention.
To remedy this, the new Walloon Waste-Resources Plan (PWD-R) has set an ambitious target for 2025: to increase the number of Walloon households composting at home by 23%. But what does this mean in terms of environmental impact? A 23% increase in the number of Walloon households composting at home will actually reduce the amount of household waste by 18,200 tonnes per year and reduce the carbon footprint by 637 tonnes of CO2 equivalent (according to the latest studies). This is equivalent to almost 9 million km driven by car, or more than 220 times around the earth! Not bad ... However, 2025 is a long way off! Our planet is getting worse and worse and is deteriorating rapidly, you only have to open the newspaper to realise this. Initiatives should be put in place so that this objective can be reached more quickly. A home composting solution should be offered even to people who do not have a garden. Neighbourhood actions should be set up to allow an exchange and an optimal use of the compost obtained. And what if we told you that this will be possible very soon? Indeed, the start-up Greenzy proposes to remedy these problems by providing you with a self-contained, intelligent indoor composter: it promises you quality compost and puts you in touch with people in your neighbourhood to give or receive compost. In doing so, Greenzy allows you to take an essential step towards the circular economy and the preservation of our beautiful planet! Interested? Learn more about it here.

Sources :

[1] Wallonia 2017 measurement campaign, figures available here: http: //


[2] Composting organic waste, Wallonie environnement SPW, 2018: http: //

[3] Boldrin, A., Andersen, J. K., Møller, J., Christensen, T. H., & Favoino, E. (2009). Composting and compost utilization: accounting of greenhouse gases and global warming contributions. Waste Management & Research, 27(8), 800-812.

[4] Martínez-Blanco, J., Colón, J., Gabarrell, X., Font, X., Sánchez, A., Artola, A., & Rieradevall, J. (2010). The use of life cycle assessment for the comparison of biowaste composting at home and full scale. Waste Management, 30(6), 983-994.

[5] Walloon Waste and Resources Plan: http: //

[6] Barometer of waste prevention in Wallonia, 2018: http: //

[7] ZeroWaste France: https: //


[1] The various greenhouse gases have different impacts. In order to better compare them and sum up their emissions, the "CO2 equivalent" is used. This is a unit that assigns for one kg of a greenhouse gas the quantity of kg ofCO2 that would lead to a similar greenhouse effect.



  1. Yves Tisserand

    I have just discovered your project in the magazine Imagine. I have been using a vermicomposter on the balcony of my flat for many years. Your composter seems to be based on a different principle, but nothing is explained on your website. Could we know more about it?

    • greenzy

      Hello Yves,
      Thank you very much for your interest in Greenzy!
      Indeed our product differs from vermicomposters. Here, no glass, but a control of the environment of the compost as well as a mechanical stirring. We will soon make a page on the website to explain this in more detail!


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