The way humans use and discard materials every day is not acceptable – but what can we do about it?
WMG’s academics and engineers are technology leaders in plastics and metals. We work with large industrial partners such as Severn Trent and Liberty Steels, as well as innovative SME’s who are disrupting the way we use and recycle materials. It is certain that our behaviour in how we use materials needs to change - but we also need to look at the types of materials we manufacture and how we process, recycle and reuse materials.
Where does all the plastic go? - Ton Peijs
Although plastic is often thought of as a single use material, it actually lasts a very long time and can be used over and over again. In the UK around 45% of plastic is recycled and 30% is incinerated to generate electricity. The remaining 25% goes to landfill - wasting the value of the material, and causing the environmental impact we are all currently talking about. Although the UK has made enormous strides in reducing this amount over the past 20 years, we are a long way behind other countries that don’t send any waste to landfill, like Germany, Norway or the Netherlands.
Levels of Recycling
A 45% recycling rate sounds good, but its effectiveness is all about how much of the value of the product is re-used.
The most effective recycling is where the product is used in the same form for the same use.
Next comes the plastic being re-used – effectively as virgin material – to produce products of the same value. The problem is that plastic materials are often down-cycled into less valuable products because waste streams often contain many different types of plastic and mixtures of plastics mostly have inferior properties to pure plastics. For recycling to become more efficient, waste collection and separation systems must be improved. Products could also be designed for their whole lifecycle - including recycling.
If the plastics cannot be re-used, the plastic can be broken down into its chemical building blocks and re-used at that level.
Why Incineration isn’t so bad
There are positive aspects to recovering energy from plastics through incineration, especially in the case of mixed or contaminated plastics that are difficult to recycle. Plastics are made from petrochemicals which are produced by the oil refining process. Plastics contain the same amount of energy as the oil they are made from and after a useful life they can be safely incinerated and converted into energy or electricity.
We need a systems approach
There is a complex problem to solve with plastics and a simple blanket ban may not be the answer if we want to create a more sustainable society. The solution could lie in a steep increase in recycling rates and the creation of a ‘circular economy’ where plastic materials are more effectively recycled at higher value uses.
Waste prevention, for example through use of less materials, is the preferred waste management option. It is followed by waste reduction through, for example reuse followed by recycling, recovery including incineration with energy recovery or compositing and as a last option, safe disposal.
Avoiding the fatberg: turning waste oil into composite materials, Dr Stuart Coles
As an Associate Professor in Sustainable Materials and Manufacturing, I’m involved with a lot of truly amazing projects. Most recently, I’ve been supervising a brilliant PhD student from Brazil, Felipe Fernandes.
Felipe’s PhD focused on working out how to turn waste oil, something that is currently converted to biodiesel, into composite materials. Waste oil is often disposed of down drains and contributes to the ‘fatbergs’ we have seen featured in the news in recent years. They pose a big problem for water companies, as it costs time, money and effort to remove them from our drains. The most common source of waste oil in the UK is from kitchens and includes fats, greases, vegetable oils, etc.
Severn Trent says up to 70% of blockages in sewers are caused by fatbergs, so by developing a polymer with industrial value, we can deal with this problem effectively and add real value in the process.
The source of oil chosen has to be easily accessible and local. We chose an abundant waste cooking oil (a blend of rapeseed oil and palm oil) from the University’s Café Library! Whilst we’ve used one particular blend for consistency, the process we’ve developed is also applicable to any blend of waste cooking oil.
First, the oil needed cleaning, so Felipe had to decide what filters to use and which impurities were acceptable in an oil-based polymer.
Next came the cleaning process itself. We took techniques from the biodiesel industry and adapted them to deal with the specific challenges of cooking oil like removing burnt batter and food. These all need to be filtered out.
Once cleaned, Felipe could focus on converting the oil into a polymer called an epoxy. We know we can make anywhere up to 100% waste oil-based epoxy, and we can tune the mixture to find the right blend to achieve the desired properties at the end.
In terms of major barriers, we didn’t really face any - this is one of the only PhD projects ever to have run relatively smoothly!
Felipe’s polymer hasn’t been used yet, but we think it will play a part in non-structural components of cars. Similar parts are used in the new BMW i3. It also has potential applications in crash structure elements - crumple zones inside bumpers etc., where the waste oil composite actually performs better than conventional materials!
What we have learnt here is applicable more widely and we will be working with other companies to develop this work further.
The PhD was funded by Science Without Borders, an initiative from the Brazilian Government and the National Council for Science and Technological Development (CNPq) They funds scholars to travel abroad, learn from institutions and bring back their new skills to Brazil. CNPq covered Felipe’s stipend, tuition fees and a budget for consumables.
Can steel evolve to become truly sustainable?
Steel is used in almost every walk of life. Its strength and formability means it can be formed into almost any shape and is also the most widely recycled material in the world. But is it sustainable? With increasing demands to reduce CO2 emissions and costs, while increasing the amount of steel recycled in the UK, the industry needs to evolve to meet the demands of the future.
UK legislation calls for carbon emissions to be cut by 2050 to 80-95% of 1990 levels and increasing our use of recycled materials has a big role to play. Steel has always been widely recycled; for every tonne of new steel produced, just over one third uses recycled materials. But with 80% of the UK’s steel being recycled abroad, we need to do more in the UK to reduce our reliance on new steel produced from virgin raw materials and maintain a UK based steel industry.
What’s driving the need to reduce emissions?
Historically, the key driver for recycling steel was the high price of raw materials, but more recently climate change and the need to reduce CO2 emissions have become the primary factors.
New steel, made from iron ore and coking coal in a traditional blast furnace, produces high levels of carbon emissions. For every tonne of new steel made, around 1.8 tonnes of CO2 is released. An electric arc furnace produces about a quarter of that for the manufacture of steel using recycled materials.
The main sustainability challenge for the steel industry
Without more recycling, the UK steel industry can’t meet its 2020 emission targets. It needs to innovate to change its processes and achieve these goals.
Dr Zushu Li, Reader and EPSRC Fellow in Manufacturing at WMG, said:
“We need to evolve to hit our carbon emission targets. We have the capability to recycle more, and that’s the change we need to implement. By increasing our use of recycled material, we can produce new grades of steel that are stronger and lighter, meeting the needs of many industries that are trying to meet emission reduction targets.”
How can we recycle more good quality scrap steel?
One of the challenges in recycling steel is contaminants in recovered materials. When a car is recycled; the seats are removed, the fluids drained, but some of the wires that run through the whole car remain, so the scrap contains non-steel elements that can build up each time the steel is used and recycled.
Liberty Steel UK is involved in a collaborative R&D project with WMG and other partners looking at sources of scrap steel and matching the quality of the materials and the distribution with potential uses.
Greg Clarke, Manager of Change and Business Development at Liberty Steel UK, said:
“By improving the recycling process, we can improve the quality of recycled materials and reduce emissions and costs. Through this project, we will improve the recycling process and increase the amount of recycled steel used in UK-based manufacturing, boosting our economy.”
For steel to survive, it must evolve, something it has been doing for decades. With environmental drivers aligning with potential cost savings, the conditions for achieving a circular economy in the UK are set. And with projections indicating a higher availability of recycled steel in the 2020s, the motivation for a scrap-based manufacturing infrastructure has never been more promising.
Garbage to Gold - saving on landfill
Delta Waste Management (DWM) based in Loxley, Warwickshire, recovers tonnes of domestic plastic materials and processes them for resale and reuse. Their focus is on reducing materials sent to landfill or exported abroad. Back in 2017 the company realised that potential value in the products they were selling was not being realised.
DWM Director, Lee Clayton, set about to change that: “We can sell processed products, but without a known composition, their value is limited. We decided to approach WMG for help to realise the increased value.” Waste plastic materials can sell for around £50 per ton, but reprocessed materials with a known composition and demonstrable properties can be worth ten times that.
DWM wanted to develop a reprocessing method that would deliver materials with higher value and identifiable characteristics. WMG had both the knowledge and expertise to provide the required support and partnership.
Kylash Makenji, Innovation Manager at WMG, commented: “We understand polymers and polymer processing, and we set out to show DWM how known processes can be used to benefit small businesses. Giving Lee the tools to generate data sheets confirming the properties and potential uses of reprocessed plastics means that DWM can access new markets and provide samples of products made with reprocessed materials.”
The key challenge for Delta and WMG was to identify the value in the end product. To do this, the team used a thermal analysis technique that can identify the polymers present, thereby giving an understanding of the material’s characteristics and its potential value.
Once a material is characterised, it is homogenized through an extruder before being thermally moulded into pellets. The pellets are then sold as feed stock for injection moulding, being useful for thousands of different products.
Delta now has a process that it can follow to characterise, reprocess and sell its waste materials for a much higher return. It is also suited to many more applications, thanks to the data sheet that can be used to demonstrate the properties.
With around 3,000 tonnes of waste materials saved from landfill so far, the impact from this project has been in reduced costs for landfill and higher value products for sale. New processes and technologies such as these will enable the UK to be in control of its own reprocessing and recycling industry.
Lee continued: “We now have a greater knowledge of material properties and can purchase waste materials with appropriate properties to achieve great results. We’ve received strong interest from a number of potential new customers and are bringing more of the processing equipment in house, so we can control the whole process.”
The insight provided by this project is already starting to impact elsewhere. DWM is now looking at styrene and polypropylene materials to see if they can be reprocessed for injection moulding. If sent to landfill, these products take 50-100 years to decompose.
Industry Day: Visit University of Warwick on 17th September for a one-day conference in sustainability to explore opportunities for collaborative R&D.
• Hear from industrial partners about their experience of working with Warwick
• Explore our cutting edge scientific research facilities
• Build relationships with researchers in your field
• Identify new collaborative research opportunities
Register here: https://warwick.ac.uk/industryday
As part of Industry Day, WMG are delighted to announce that our Polymer Innovation Network (PIN) will also return on the evening of Tuesday 17th September.
The event theme is Sustainable Polymers. If you would like to register for our PIN event please use this link:https://warwick.ac.uk/fac/sci/wmg/mediacentre/wmgevents/pinevent