The Eco Park on Charlton Lane Shepperton is providing the next generation of household and business waste treatment facilities for the county of Surrey. The innovative facilities produce electricity for the national grid and fertiliser for use in farming. It is run by the waste management company SUEZ (formerly known as SITA), on behalf of Surrey County Council, and is now fully operational, offering both anaerobic digestion (AD) and gasification as well as a Community Recycling Centre.
I am talking to Kacie Thompson, a communications manager who joined SUEZ in 2017. Kacie is from the United States but moved to Surrey in 2016 and is now happily settled in South London. She has an MSc in Corporate Environmental Management from the University of Surrey.
Could you please explain the terms gasification and anaerobic digestion?
Gasification is used to process non-recyclable ‘black bag’ waste and turn it into energy. The gasification facility at the Eco Park is designed to treat up to 55,000 tonnes of black bag waste each year, mostly from homes in Spelthorne, Runnymede and Elmbridge. The waste first goes through a screening process to pull out metals for recycling and remove any oversized waste and inert materials like brick or concrete. The remaining waste is shredded to create Refuse Derived Fuel (RDF) which is then fed into the gasification chamber. At the bottom of the chamber is a fluidised bed of sand which is heated over 700 degrees Celsius with reduced oxygen levels. The waste is broken down in the fluidised sand bed, creating a synthetic gas which rises to the top of the chamber. At the top of the chamber, the air is added to the gas and then ignited. The heat from igniting the gas is used to produce steam that then drives a turbine to generate electricity.
At the end of the process, the gases are cleaned and filtered before being released through the chimney on site. We continually monitor emissions to make sure they are kept within strict permitted levels. The ash produced from the process is currently sent to a landfill, but we hope that in future it may be able to be used as an aggregate in construction.
On the other hand, anaerobic digestion is a process that uses microorganisms to break down biodegradable material, in this case, food waste, in the absence of oxygen. At the Eco Park, food waste goes through a pre-treatment process to remove any unsuitable items (like plastic bags) and shred the waste into small pieces. Water is then added to the food waste and the mixture is fed into a series of tanks containing microorganisms that break it down in the absence of oxygen, producing biogas that is used to generate electricity. After the biogas is removed, excess water is removed to create a compost-like material called digestate that can be used on farmland to improve soil nutrition.
Would you say that the Eco Park is a power station?
That is how we like to think about it. It is a power station producing electricity, but the fuel used comprises non-recyclable materials and food waste. We are subject to strict emissions controls and the gases produced from both processes are monitored and cleaned before they are released via the chimney.
The benefit of having the plant here is that local residential waste can be used to generate enough electricity to power over 4,000 homes, which is an area approximately equal to the size of Shepperton. Also, refuse trucks from Elmbridge, Runnymede and Spelthorne do not need to travel far, which cuts down on emissions.
We could say that the treatment of local household waste at the Eco Park is helping to make the community more self-sufficient in terms of waste management, whilst also contributing to energy security. In 2022:
- *The Eco Park generated a total of 25.4 GWh of electricity – 16.2 from the gasifier and 9.2 from the anaerobic digestion facility
- Of the total electricity generated, 15.9 GWh was exported to the grid
- The facility exported enough electricity to power 4,262 homes for the entire year, more than all the homes in Shepperton
- 44,035 tonnes of non-recyclable black bag waste processed
- 25,226 tonnes of food waste processed
- 4,164 tonnes of digestate produced, sent to be used as a soil improver in agriculture
**Between 2021 and 2022, 52,561 tonnes of household waste was collected in Elmbridge (from kerbside and bring banks), out of which 26,944 tonnes were sent for recycling, reuse, or composting. This represents a recycling rate of 51.3%. There are 136,795 people living in Elmbridge (according to 2019–2020 statistics), and we generated 441.8kg of waste per person during the period 2020–2021.
What residents can bring to the recycling centre:
Do you think we as consumers could take more responsibility for the waste we generate?
The main thing we try to encourage people to do is to really think about how items could be reused, for instance by passing them on to someone else. We would love to see the residents reduce waste by re-using and repairing more of their items rather than disposing of them.
What about the items we put into our bins?
One of the biggest problems we currently have is that lots of people put batteries (which need to be recycled in a special way) into their household waste bins. Some still have use in them and can be a fire risk if not properly disposed of, causing a safety concern for staff and visitors on waste sites and risking damage to important infrastructure. This is a problem nation-wide, and it is something we would like Surrey residents to be more aware of. If they are throwing away something that has batteries in it, they should be removed before putting the item in the appropriate bin. Batteries can be safely and separately recycled at your local community recycling centre or in a supermarket, where there are often dedicated battery collection points.
For instance, in Weybridge, Waitrose has a collection point at customer services, and there is one in Morrisons (in the downstairs hall next to the escalator). Also, printing cartridges and cooking oil can be brought to the recycling centre in Charlton Lane, Shepperton. When it comes to collecting food waste, you can line your caddy with any type of plastic bag, e.g., old shopping bag or specially purchased plastic bags on the roll. ***
Surrey Environment Partnership – Food waste recycling (surreyep.org.uk)
Another issue is the contamination of recycling bins. Some residents put food-soiled items like pizza boxes or used kitchen roll in their recycling bins, but this kind of content cannot be recycled because soiled paper and cardboard will reduce the quality of paper products created from the recycled material. Such items should therefore be considered non-recyclable. The content of the recycling bins should be kept as dry as possible and clean from food contamination.
We as consumers often feel we cannot help generating so much waste. In an ideal world, if we managed to minimise our general and food waste, replace plastic bottles with refillable glass bottles, cut down on packaging, and use only natural fabrics, would it put companies like SUEZ out of work?
Absolutely not. At SUEZ, we focus on waste prevention and elimination and moving materials up the waste hierarchy. To reduce volumes of non-recyclable waste, we will have to recycle more and more, so we will still have a role to play in processing items for recycling and making sure we make the most out of our resources. And there will always be food waste to deal with, so anaerobic digestion facilities.
Do you think there is a conflict of interest between us the consumers and the waste management companies and experts?
Our goal is always to minimise waste and move materials up the waste hierarchy, so no, I don’t think so. If we take paint waste as an example. Paint used to be something that could not be recycled, but we designed a solution that helped prevent waste, reduced disposal costs for the council and raised money for charity. We opened a reuse shop where tins containing a certain amount of paint could be put aside and resold for a suggested donation to Macmillan Cancer Support. Also, new legislation and policy reforms are being introduced that will transform the waste industry and drive recycling rates. Extended Producer Responsibility will require manufacturers to take more responsibility for their packaging waste, incentivising them to change to more environmentally friendly packaging and ensuring the price of the product reflects the environmental cost of end-of-life disposal. Alongside this, there is a new policy coming into effect that will mandate separate food waste collections from all households and businesses, making anaerobic digestion facilities like we have at the Eco Park even more important. These policy changes will be a big transition in the industry and waste and recycling experts have an important role to play in implementing these changes.
SUEZ has adopted a zero waste and circular economy strategy.
I understand that SUEZ participates in charity events. Could you tell us more about them?
At a national level, we have partnered with Macmillan Cancer Support, and we have raised over £500,000 as one of their UK corporate partners.
In Surrey, ten percent of profits from our five reuse shops (nearly £60,000 to date) is donated to various local charities each year. We have supported a huge number of local charities over the years, including the Woking & Sam Beare Hospice and the Princess Alice Hospice. We are about to launch a new community fund for Surrey charities that will use the profits that we make through the reuse shops to provide grants of up to £10,000 for bigger charitable projects that address community and environmental issues. We are very excited about this.
Many of our social value activities are connected to reuse and waste minimisation. For example, we collect a great deal of mobility equipment, like crutches and walking frames, that are restored and sent to be put back into use within the NHS. We are engaged in social initiatives in Surrey that many residents may not know about. For example, we have partnered with HMP Ford (an open prison) where we sponsor a bicycle workshop where prisoners can acquire mechanical skills. We collect bikes that are not in good working order and send them over to the prison, where they are worked on and then sent back and sold back into use, usually for around £25-£100. Additionally, through the Released on Temporary Licence scheme we give prisoners who are coming to the end of their sentence the opportunity to apply for a job with SUEZ as part of a rehabilitation through our employment programme which has been very successful. This is something we are very proud of. We are also doing a lot of work with the Ministry of Justice to help encourage other employers to set up similar programmes.
On a more personal note, what hobbies do you have?
Gardening really. I have a huge vegetable garden and I go to the reuse shop and get stuff for it there, so I am never short of plant pots. I also bought some clay roof tiles, which I use for kerbing in the garden. My goal is to become self-sufficient in terms of growing food, or at least as much as possible in London.
I would like to take the opportunity and thank you Kacie and the whole SUEZ team for doing such a great job of managing our waste in these magnificent facilities, and I hope that we, as consumers, will manage to discipline ourselves and take time to acquire new skills and knowledge that will help us deal with and segregate our domestic waste, for example by learning more about what we can put in our bins and what we can bring to the Charlton Lane, Shepperton recycling centre. Thank you again for taking the time to talk to us.
*Figures provided by Kacie Thompson SUEZ
**What do we do with your waste and how much do we recycle? – Surrey County Council (surreycc.gov.uk)
***Surrey Environment Partnership – Food waste recycling (Surreyep.org.UK