If you intent to start to deal with your organic waste properly there are some facts and options, you should be aware of. We listed below some basic information that will help you ask yourselves the right questions so that you can implement a coherent organic waste management scheme.
According to the Mac Arthur foundation separating thoroughly natural material that can integrate the biosphere safely is one of the key component of circular economy models (see their famous infographic). Doing so generates multiple benefits:
- Avoiding moisture in your bins which will:
- prevent technical components (non organic) to lose their recycling or reusing potential,
- permits less regular trash collections as the size and bad smell will be reduced.
- Preventing it to end up (according to where you live) in:
- sanitary landfill causing harmful greenhouse gas emission,
- incinerators bringing little calorific value,
- open dump site contaminating air, water and creating a breeding ground for harmful bacteria and insects.
- Providing opportunities to:
- generate local energy,
- fertilize fields,
- capture carbon,
- provide free mulching.
- Organic waste accounts for 30% (in OECD) to 70 % (in developing countries) of the total waste amount of households bins.
- Up to 40 % of the food produced worldwide is thrown away. If food waste was a country, it would be the 3rd biggest producer of green house gas. In France 36% of green house gas is produced by the food industry.
We wrote an article detailing specifically the food waste issue and possible solutions: click here to read it!
What can be composted?
Everything that is or has been edible can be regarded as organic waste.
A good waste management process starts with preventing food waste in the first place: read our detailed article to get tips about it. Soft byproducts like banana peels, the leaves of cauliflowers, radishes, leeks or beetroots can be easily composted although there are also options to cook and eat them to consider first!
Some organic material might impaired the treatment process:
- Bread, Limes, lemons, oranges, as well as garlic, onions and leeks should be prohibited for worm composting and might slow down the composting process if they represent half of the amount of waste.
- Animal and dairy products as well as soups, sauces, purée are OK for methanization but might be prohibited for small scale composting to prevent pest and smells.
Eggshells can help to add calcium in your compost which is really good for plants. However be aware that hard minerals materials, such as eggshells, mussels or oysters, take a lot of time to decompose. Crush eggshells before to throw them away to accelerate the process.
Leaves, branches, invasive species, coming from your garden or fields, can of course be composted, but be aware that there is a risk that some undesired seeds remain in the compost if they have not been neutralized during the thermophile process. Some decoration made out of natural material like flowers might have been treated with chemichals not to decompose at a normal pace.
Paper and cardboard
Non-edible, man-made materials like cardboard, cups, newspapers, bags, can sometimes be composted if they do not contain chemical components. The main problem might comes from staples or glue (rather than inks). Be cautious, check the composition of the material looking at textures, gaudy and shiny colors or labels.
Don’t compost them! The fact that some so-called compostable “bioplastic” bags “disappear” with time might in fact just mean that they’re breaking into tiny pieces that are invisible to you. Those are still harmful for the environment and some items will only decompose in industrial composting facilities.
How to compost?
1) Collect separately organic waste
Learn about how to choose and implement smartly waste containers: read this detailed article! Also, find useful resources about signage on this page. Even so it will be the first step of your waste journey, it should in fact be decided last: according to the waste treatment option(s) you’ll opt for and with whom you will be working for it collection/treatment with.
To keep in mind:
- Everything that is compostable is not necessarily composted. Customers might not be accustomed to your process and throw their compostable stuff elsewhere.
- The waste you will encounter in the gardens (leaves), in the kitchen (peels), open spaces (compostable cups) or dining room (leftovers) might be very different in volume, composition, and might involve very different people (employees, visitors, etc.). It is thus relevant to design appropriate containers, set up and signage for each place.
- Organic waste containers can bring smells, pests and generate heat or gazes.
- Organic waste is super heavy and dirty, containers have to be easy to transport (size, wheels, few stairs) and washable.
- They are some devices that can help you by dring out your organic waste in order to make them taking less space, but also to prevent smells and pests which will allow less frequent transportation. The output, a dried and shredded organic matter cannot be considered as regular compost.
2) Transport and transform
If you’re an organization/company generating a lot or organic waste, you may not be able to process the organic waste yourself. For example, if you’re a restaurant providing more than 50 meals a day, home composting would require a nearby garden with at least 6 m² available, and with curious and tolerant neighbors. Other below mentioned techniques are often too complex and capital intensive to be handled by amateurs. If you do not handle the organic waste yourself, it is highly probable that the service supplier you will be working with (either NGO, entrepreneur or municipality) will also take care of transportation.
To keep in mind:
- The service supplier might provide appropriate containers with a deposit system.
- The cost of organic waste collection and treatment can be mutualized by several neighboring structures and balanced by existing or incoming tax cuts.
- The service providers can resort to several waste treatment options that will impact what you will have to separate or not.
- Different possible transformation techniques include:
- Worm composting
- Feeding for animal or larvae
Always keep in mind the waste hierarchy to frame how you should focus your efforts for greater impact. Here is a good one for food waste from the United States Environmental Protection Agency (EPA):
How does composting work?
If you are lucky enough to compost yourselves, here are some explanations about how it works. Composting somehow tries to follow some natural ecosystems principles.
You are not alone! Bacteria, mushrooms, insects and many others will help you process the organic waste. Your composting site can be located on plain earth and benefit from potential trees, bushes but industrial composting processes also work on concrete. All species below are more than welcome, even mice if it does not get in the way of sanitary rules or good relations with neighbors are not a threat in itself.
It will take around 3 to 6 months to transform a heap of organic waste into mature compost in industrial composting site. It can take 6 to 9 month according to quantities and climate and small scale composting. Proper maintenance, ecosystems and input will help you keep with the delays but nothing will speed up the pace of nature without damaging the quality of the output.
The composting process require a balance of moisture and air:
- A well-balanced compost NEVER STINKS!
- Composting consist in a natural process called aerobic digestion which means that the above-mentioned living beings will thrive provided that there is oxygen, without them other kinds of bacteria will develop and generate methane. Keep the air flowing by turning the organic waste upside down at least once a month, having a well dimensioned container and adding branches, leaves or shredded wood.
- For each volume of organic waste with nitrogen (kitchen scraps and leftovers, freshly moaned grass in thin layers) you should add an equivalent volume of carbon (dried leaves, newspapers or cardboard, shredded untreated wood, compostable straws…)
- An appropriate moisture level is important, a roof or lid is required to protect your compost from glazing and drying sun, or from heavy rains. Adding carbon will help you maintain a good moisture. Watering the compost might be needed at times.
Tips to make it better!
Although composting tries to imitate nature, if you want your composting site to process enough volume and/or quicket, some actions are required from you and your stakeholders.
The smaller the pieces of organic waste, the faster they will decompose. Huge chunks might need to be cut or torn in smaller bits.
Good set up
If you want to process 1 cubic meter of organic waste quarterly you will need:
- A container that will receive fresh organic waste.
- A nearby container with carbon inputs.
- A maturation container where the almost mature compost will be able to finish its maturation.
- Some tools to monitor and maintain.
- Enough space in a nearby garden.
Signage and governance
No matter how good the set up if the human factor is not taken into account. It is important to involve your stakeholder by training and mobilizing them. Tutorials can be found on the internet, a team has to be created to define who will bring the organic waste on a daily basis, who will mix it monthly and transfer it quarterly. Some open events can be organized quarterly to distribute the mature compost and raise awareness about the impacts and requisites of composting.
Good signage is crucial both next to the collecting bins as mentioned previously but also onto the composting site to explain to potential new employees, or simple bypassers the goals, good practices and benefits of composting
If one cubic meter composter is not enough, you can add others, up to 4 new composter, one more being dedicated to maturation. For bigger quantities which, of course, implies bigger spaces, you can opt for windrow composting that you can improve with passively or forced aeration. In vessel composting allows you to speed up the maturation process by easing the mix and aeration through a manual or automated barrel rotation.
This is a screenshot from the free course about composting:
Municipal solid waste management in southern countries
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