Why is Food Depackaged and How is it Done??

Social IssuesEnvironment

  • Author Steve Last
  • Published June 28, 2022
  • Word count 1,280

How is Out of Date and Unwanted Food Depackaged?

Why is organic food depackaged to remove wrapping materials?

The reason is that unused food was once simply thrown into landfills, or burned in mass-burn municipal incinerators, and this is no longer socially or environmentally acceptable for numerous reasons. Instead, the requirement is now for the organic content to be anaerobically digested, and for the rest of the material to be recycled. In reality, the rejects almost always end up in a landfill or are inefficiently incinerated, but this is far better than the whole lot going to a landfill or for incineration.

Packaging prevents spoilage, preserves freshness, and allows smaller portions of food to be sold. It's not perfect. After the sell-by date, the packaging becomes problematic. When food cannot be given to food banks or is not suitable to be fed to animals, the packaging must be removed prior to, or upon arrival at a Materials Recycling Centre. Invariably, without using a depackager to remove the plastic and other rejected materials, the packaging present prevents anaerobic digestion and composting systems from processing the contaminated food waste.

Depackaging and Climate Change

Food waste is a big contributor to greenhouse gas and global warming, as readers who followed the COP26 conference on curbing global warming will know.

Incredibly, we waste so much food that if global food waste were a nation, its climate-changing influence would be similar to the 3rd-largest in the world. It would rank below the US and China.

So food producers, the catering and hospitality business, the agricultural industry, and everyone else, including you and me, must modify our wasteful ways urgently.

Renewable Energy Foods are "Energy dense"

Not everything about this is bleak. Here, a difficulty can be a huge opportunity because food waste is full of energy. Most favourite foods are heavy in calories. Just think how much energy food gives an athlete. Enough for some of them to run a 25-mile marathon before they eat again!

Depackaged food can be utilised as renewable energy. It's made from recent sunlight, not geological (or fossil) energy. It's sustainable since it's renewable.

Climate-neutral Renewable Energy

In the future, we'll acquire a lot of our energy and make biogas, which is refined to become biomethane, which when compressed can fuel the largest of trucks. Yes! All that is possible from uneaten/ inedible food.

Depackaging creates two outputs. First, organic materials (like a pulp or soup), and other materials (called "rejects").

Why depack?

We depack to use organic content (as a "soup" or "paste") to make biogas to be used as a source of renewable energy. The solution is to feed organic matter to anaerobic digesters, which produce renewable methane. This will replace natural gas use. Natural gas has to be phased out as an energy source because it is a non-renewable, climate-damaging fossil fuel.

Digesters produce biogas which is mostly methane, which can be refined into "renewable natural gas" (RNG). RNG is non-fossil-fuel sourced natural gas replacement. It's also utilised as a fuel for heavy transport, which is much cleaner for use in cities, and on the road, than diesel and petrol.

Depackagers' Goals Go Beyond Food Removal

Removing food from packets and wrappings to make a clean organic soup for a biogas digester is no longer the industry's only goal.

The holy grail of depackaging is to take the "rejects" and, if clean, sell them for:

• plastics to be recycled by reusing the resin or burned in biomass boilers to extract energy, as a saleable product;

• recyclable metals

• soil-making grit and inert materials (subject to heavy metals content and other regulatory requirements).

Avoiding garbage disposal to landfills has both environmental and financial benefits. In the UK, landfilling or mass-burn incineration incur a charge of approximately £150 GBP ($200 US) per tonne.

Both organic soup and depackaging machine rejects can be profitable recyclates using the latest generation of food waste depackaging systems.

Whether it's uneaten, out-of-date, out-of-specification food, or mixed municipal (black bag) garbage, the solution is the same. They are essential machines that:

• Open packaging

• Separate solids from liquids

• Separate stones, grit, sand, silt, and clay

• Create a reject materials output stream.

Microplastics Avoidance

Depackaging has shifted from particle size reduction to less hazardous methods that prevent microplastics from being made in the process. Recent technology models keep film, bags, and packets largely intact instead of pulverising them into microplastic pieces which was the old way.

All mechanical depackaging machines sort by physical properties. The older types include hammer mills, shredders, paddle wheels, etc. Shredding garbage may minimise clogging and equipment stoppages, but it creates microplastics in quantity. So, the current best machines have been designed to pull and push the reject materials out whole, rather than reduce everything to a small size.

For the survival of our oceans, society must avoid making these small plastic fragments that all living creatures are now eating. Microplastics are the largest experiment on what global ecosystems can tolerate before collapsing.


Many depackagers combine separation approaches. These commonly start with a counter-rotating dual-auger mixing/feeding hopper. As needed, they add water. Older models shred and mill to separate.

In advanced depackagers, plastic and metal cans are split open and stripped clean (and virtually dry) employing rotation, turbo water currents, and vortex-in-air effects combined with severe shaking. Organic pulp drains off through self-cleaning strainers.

As needed, downstream from the main depackaging unit, additional equipment is added. Sedimentation removes heavy inert elements, small metal bits, etc., while floating plastics and woody materials are scooped off the top. Screw presses can be used to dewater organic soup for biogas digestion.

Depackager machinery can commonly process up to 40 tonnes per hour of food waste.

Depackaging Technology Conclusion

Since their beginnings, food waste depackaging devices have improved. The first depackaging devices were bag openers and shredders used for composting. The market was tiny, therefore suppliers modified existing waste processing mechanisms for use with food waste. The latest models are so much better because they were designed and built for the job.

"Wet-process" anaerobic digestion facility operators are a growing group of renewable energy companies that employ these devices to reduce difficult materials entering reactors and they are developing new market opportunities from clean rejects. Using the best depackaging equipment should also reduce costly digester cleanouts owing to plastic and silt clogged reactor tanks.

Many nations are expanding the collection of source-separated food waste from businesses and families. Thus more countries are installing machines that cut food packaging and remove the organic food particles. This technique helps governments meet COP26 "Net Zero Carbon Emissions by 2050" obligations and may eliminate the need to landfill organic waste.

Modern depackaging equipment uses multiple characteristics and less traumatic forces, creating a reject output stream that can be sold as SRF or RDF, as well as single plastic polymer classification and the sale of premium recycled plastic resins, which are in high demand and command a high value, especially in countries that have implemented a plastic tax on single-use plastic use.

Newer machines are more robust, and using augers instead of conveyors reduces downtime. Eliminating shredding and grinding reduces energy use.

Food containers, plastic containers, and cans won't clog or shatter these new machines.

Drycake's Twister depackagers are an example of machines that treat waste properly as described above. The best depackaging machinery firms provide high-value waste treatment. They pledge to make far fewer or no microplastics in their depackaging machines. This is important as these machines must decrease microplastics to prevent environmental contamination.

Good food waste management reduces damage and increases sustainability. New depackaging methods have been described here. When they succeed, world sustainability and the prospect of tackling climate change are improved.

Steve, the author of this article has written additional articles on the subject of food waste depackaging at: https://wastersblog.com/101429/food-waste-depackaging-methods. You are welcome to take a look at that website, and also to request further information via steve@ipptsassociates.co.uk.

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