Tl;DR: It is turned into alternative fuel (95%). We are currently experimenting with technologies where the non-recyclable plastic is pressed into a plywood substitute to add a second life.
Understanding the environment we’re working with
Around 40% of all households in the world are not connected to a formal waste management system.
That means that waste is either burned in front of houses or littered in the environment.
Especially in coastal areas, the path into the ocean is short.
In countries where there is no proper waste management, GDP is usually low.
That means that everything that has at least a bit of value will be collected by informal waste pickers.
Recyclable goods like plastic bottles are collected by an informal sector today already. These products can be sold and generate an income. Anything that has no or negative value is left behind.
Understanding the plastic we work with
All plastic credits purchased through CleanHub pay for non-recyclable plastic and negative-value plastic collection and recovery. The reason for that is simple, 80% of all plastic that enters the oceans are multi-layer or flexible plastics. Both are technically not possible to recycle or there is no infrastructure (sorting & recycling-process) to repurpose the flexible plastic. Investing to collect recyclable plastic like water bottles would have almost no impact, as these have inherent value.
Reduce, reuse, recycle - then what?
Since all the waste that we collect already exists, we can’t reduce it. We don’t know how one would reuse an old candy wrapper or a chips bag - so this is also not an option. And as we learned, recycling is not an option either. So what next?
Many don’t know that Reduce, Reuse, Recycle describes the hierarchy of priorities in the waste management hierarchy. And this hierarchy has two more layers, which are a bit more uncomfortable to talk about, but this is where most of the global waste ends. These are recovery and disposal.
In non-waste-management language recovery means incineration of waste to win back heat and energy in a controlled process, and disposal means dumping on a landfill (ideally managed). The waste management hierarchy is widely used in the EU Waste Framework Directive or the UNEP Basel Convention.
We strictly follow the waste management hierarchy to recover the waste’s energy through co-processing technology: the incineration of trash during the production of cement.
Wait...what? That doesn’t sound sustainable...
True. To put it in the words of Sir David Attenborough: ‘Everything that we can’t do forever is by definition not sustainable.‘
And to strengthen that, let’s add another conservation heavy-weight:
“Everything man does creates more harm than good. We have to accept that fact and not delude ourselves into thinking something is sustainable. Then you can try to achieve a situation where you’re causing the least amount of harm possible. That’s the spin we put on it. It’s a never-ending summit.”
These words were spoken by Yvon Chouinard, Founder of Patagonia.
And these are the words we live by. The most problematic plastics when it comes to ocean pollution are flexible and multi-layer plastics. They can’t be recycled and letting them enter the oceans is not an option.
Among all recovery options, we’ve looked at co-processing stood out by far as the best option, doing the least amount of harm. It is available almost everywhere, there is no investment needed to erect power plants just for the sake of burning waste, and it is an immediate remedy to plastic pollution.
Disposal is not an option for us - not just because the waste management hierarchy says so.
Let us take you through our decision-making process and some of the critical questions, we asked ourselves. Because with all the advantages co-processing comes with, we know that it is not flawless.
Why landfill disposal is not an option for us
There is evidence that plastic exposed to UV light, starts emitting greenhouse gases like methane and ethylene. This process does not stop once started. The emitted gases are more potent when it comes to climate change. If landfills are not covered the plastics sitting there will emit these gases.
Further, the landfills we saw both in India and Indonesia are not sanitized. The landfills are more open dumps. A toxic cocktail of diapers, medical, electronic, and other household waste is dumped on unsecured ground. The leachate trickles into the groundwater and poisons it with heavy metals and other pollutants (leachate is the disgusting liquid at the bottom of your trash can when it’s not emptied on time). These landfills are constantly on fire, either through self-ignition or on purpose to reduce the waste volume.
On top of that, these dumpsites attract entire villages, which live on a breeding ground for diseases. The people living there roam the landfills to find anything that is of any value.
Landfills are the entry point for plastic waste to the environment
These are all reasons that would speak against putting plastic there. But it continues. The plastic we collect is very lightweight. Imagine chips bags, shopping bags, and candy wrappers. At the slightest gust of wind or with the heavy rains of the monsoon, it’s washed away, and we’d run a high risk of breaking our promise that we collect plastic waste before it enters the oceans.
Since March 2022 several massive fires broke out at Delhi’s Ghazipur landfill, each leading to a huge cloud of toxic smoke enveloping the region. Authorities blame the outbreak on the recent extremely hot weather conditions.
The government is currently looking for a new dumpsite for more than 2,000 tonnes of waste that is overloading this landfill which is estimated to hold 14 million tonnes of waste.
Comparing different methods of dealing with non-recyclable plastic
With recycling and landfills off the table let’s look at different recovery methods. Some of them are better than others, do less harm to the environment, and reduce the carbon emissions of particular industries.
In most developing countries, the current modus operandi is burning waste openly - like we saw and felt with our own eyes and smelled with our noses during our research trip to India and Sri Lanka in 2019.
Open burning is the worst form of incineration - the fire releases fumes into the air without any filter. None of the energy during open burning is won back. And this is the reality - it happens every day and every hour on different scales (Wiedinmyer C., Yokelson R.J., Gullett B.K. Global emissions of trace gases, particulate matter, and hazardous air pollutants from open burning of domestic waste. Environ. Sci. Technol. 2014;48:9523–9530. doi: 10.1021/es502250z.)
Under all circumstances, we wanted to avoid the non-recyclable plastic we collect ever ending up on a landfill that burns under the open sky. Or that it ends up in the ocean where it will do harm for the next 1’000 years and influence the health of the ecosystem that we will need most to keep our climate under control.
An unintuitive decision - turning to cement
So we started looking for alternatives - and took an unintuitive way. We’ve partnered with the cement industry. Yes, THE cement industry that is responsible for 6-7% of global carbon emissions. Before doing that we wanted to make sure that we’re not causing more harm than good. So we got into the weeds of it to learn about the challenges of an industry that we’re all customers of, every day.
There are two reasons why cement production emits so much carbon. They need temperatures of 1250°-2000°C because they are melting limestone. The calcination process is responsible for around 50% of the cement industry’s carbon emissions and is not fuel-related. But these extreme temperatures can only be achieved by burning fossil fuels like coal and lignite, which are responsible for around 40% of a cement plant’s carbon emissions. The other 10% come from supplying the raw materials.
Co-processing as an established technology...
The exceptionally high temperatures in the kiln have one significant advantage. They destroy everything that you put in that kiln. In Europe, many plants operate on up to 80-90% of waste of all forms: hospital/biohazardous waste, toxic waste, sewage sludge, plastics. It’s the safest way to recover these materials, and they are firing a process that happens anyway - no matter if the waste exists or not. That’s why it’s called co-processing. Co-processing utilizes the heat to both destroy and win back energy from waste that has no place in a circular economy.
In countries like India or Indonesia that still run on 80-90% non-renewable, primary fossil fuels are dug up just to be burned.
...with the potential to reduce the carbon footprint of cement
While plastic is still a fossil-based fuel source, using it as an alternative to coal can reduce carbon emissions by about 25% (compared to coal or lignite). This is because plastic contains more energy than coal and burning plastic emits less CO2 per GJ compared to coal. To make it more clear: for the production of 1 GJ of energy, burning plastic produces 75 kg of CO2, while coal produces 96 kg of CO2. (Panda, Achyut & Singh, Raghubansh Kumar & Mishra, Dhanada. (2017). Thermolysis of waste plastics to liquid fuel A suitable method for plastic waste management and production of value added products - A world prospective. 88. 13-18; Kristina Juhrich, Umweltbundesamt, Climate Change 28/2016, CO2 Emission Factors for Fossil Fuels; Cement Sustainability Initiative (CSI) The Cement CO2 and Energy Protocol, Version 3 CO2 and Energy Accounting and Reporting Standard for the Cement Industry.)
However, since plastic is made from oil we won’t call this a green technology - as soon as we see a way with an even better life-cycle performance to treat the waste, we will switch. We have that cemented (pun intended) in our contracts. Further, we need to pay the cement industry to co-process the waste.
We have no natural incentive to stick to co-processing once other options emerge.
So: what happens to the plastic?
One other big advantage of co-processing is that we have absolute professionals on our side. It helps us in our approach for tracing the material and overall accountability.
A cement plant is engineering excellence. The entire process is monitored and under constant quality control. That’s why on arrival at the cement plant, our plastic goes through a laboratory to ensure that it can be safely used in the kiln. It is then shredded and fed into the cement kiln for incineration.
Compared to other incineration methods, this is a clean and safe process. This is mainly due to the extremely high temperatures and long residence times in the kiln. It leads to the destruction of the material and is not leaving ashes behind - a so-called zero-residue technology. Minerals like dust that might stick to the plastic are recycled into the cement.
Further, there is an alkaline atmosphere in the kiln, and the temperature profiles are constantly monitored and managed to avoid the formation of dioxins and furans.
If CleanHub sees this as bridge technology - where is that bridge leading?
Co-processing is not flawless - like some others in our industry like to position it. But it is the best bridge technology there is today. If we want clean oceans we need to focus on non-recyclable plastic.
Our founders’ initial research started at a Cradle2Cradle congress after being inspired by a TED talk on the topic. We are rooting for all companies that are putting solutions on the market that are designing waste out of our system. But we need to face the truth that these are still niche solutions, that will need time to scale. With ever-increasing prosperity and populations, experts expect the amount of plastic usage to triple by 2040.
It is obvious that innovation needs to happen upstream and downstream - in the packaging industry but also in the waste management industry. The highest priority is to make sure that our current system is not irreversibly destroying our planet. Until we learn as a society to keep our home planet clean, we will need organizations to clean up after ourselves. And like the packaging industry, waste management needs to start with reducing. Reducing the amount of plastic that enters our oceans.
Some of the other solutions we’re looking at
In regards to the non-recyclable plastic, we are in constant contact with other solution providers. Among others, we are exploring options with a company in India that turns high-quality multi-layer plastics into a plywood substitute - but the volumes are still small and they don’t accept all plastics either.
Chemical recycling
We are observing the developments in the chemical recycling industry very closely. However, most of the solutions are still turning plastic into diesel or kerosene - which again is only fuel. In that case, it consumes less energy to directly use plastic as a fuel in the cement industry, instead of going through energy-intensive depolymerization or pyrolysis efforts to produce a fuel that eventually will be burned. We’re placing our hopes on this approach to one day turn plastic back into plastic.
Construction material
Other developments go in the direction of integrating plastics into construction materials, like tiles for roofs or bricks. We are still skeptical about this as a solution because it is unclear if the chemicals within the plastic will not off-gas in the houses. Furthermore, at the end of the lifecycle of a house built of a mixture of plastic bricks, these bricks won’t be recyclable either and end up in some landfill.
Long story short, there is no better solution available to us today than co-processing but we keep our eyes wide open. We have a lot of flexibility in our contracts and motivation in the team to switch to true circular solutions, once they arise.
The outlook that keeps us optimistic
In the meantime, we continue to build a vast network of waste-collection projects to keep our home planet clean today and are ready to collect and provide the raw materials of the future, once materials are designed for a truly circular economy. 
Because the networks we’re building today can be utilized for all materials in the future - we decided to focus on the material that does the biggest harm to our planet today. Don’t forget that 80% of all plastic entering our oceans is non-recyclable. This plastic will be lost in the oceans forever - until it re-enters our food chain. To the best of our knowledge, we are the only ones in the market who focus on this particular - and by far the biggest - issue of plastic pollution. And we can solve it. Sustainability means progress - and we’re looking forward to progressing with you.
If you want to learn more, send us an email at rodney@cleanhub.com
