Chief Executive of the Anaerobic Digestion and Bioresources Association (ADBA), Charlotte Morton discusses the positive effects anaerobic digestion can have on wastewater treatment and how water companies can best utilise it for sustainability.
What are the key benefits of anaerobic digestion as a technology?
Anaerobic digestion (AD) is the natural breakdown of organic matter, producing biogas also known as biomethane and biofertiliser (called digestate) in a treatment unit called a digester. The key benefit of the technology is that it treats organic wastes such as food waste, sewage, manure, slurries - that would otherwise emit harmful gases in landfill or during incineration. It also produces biofertiliser as well as biogas, a green energy source that can be used for electricity generation, heat and transport fuel.
AD can reduce the carbon footprint of hard-to-decarbonise sectors such as heat, transport, waste management and agriculture. It is a mature, readily available technology which creates a sustainable circular economy.
Why do you think that reusing wastewater for energy is important?
Reusing wastewater follows the principles of the circular economy and helps reduce greenhouse gas emissions. With processes such as AD it is possible to generate the energy required for treatment with surplus bio-gas sold to the gas grid. The surplus biogas output can be sold towards either heat or electricity generation. This helps to:
- Achieve carbon neutrality for the wastewater treatment process
- Support the water industry’s bid to achieve net zero emissions in their operations by 2030
- Support the UK's overall Net Zero by 2050 target
There are currently 163 wastewater plants operating in the UK, processing mostly sewage sludge. The wastewater sector is generating around 2.7 TWh of biogas per year – a large proportion of which can power the wastewater industry itself. If all of the UK’s wastewater were treated through AD, the industry could generate a total of 5.8 TWh per year. That’s the equivalent of providing electricity and heat for around 500,000 homes.
What do you think are the most pressing challenges facing the wastewater and AD industry over the next decade?
Ensuring it stands up to ever increasing environmental scrutiny, and as a leader in the action to mitigate climate change. The AD industry’s greatest challenge is ensuring it can reach its full potential and maximise deployment across the country, and the globe.
In addition, an issue that cuts across the two sectors is the co-digestion of sewage sludge and food waste, with current regulation imposing a significant monetary burden that heavily disincentivises the efficient allocation of feedstocks to plants.
What role does the Government play in the delivery of wastewater and anaerobic digestion solutions?
The Government sets the standards that the sector must follow to operate safely and optimise its performance. The main objective is to ensure plants adhere to best health and safety and environmental practice and that the most efficient process is in place. The Government must also support AD innovation to help the sector on its path to financial independence. In a letter to the previous Chancellor, we made a proposal for a virtual Centre for Anaerobic Biotechnology and Bioresources Research (CABB) to build a collaborative platform on which research funding can target key issues and optimise industry performance to get it off subsidy. CABB would not only transform the sector’s efficiency and productivity, cutting costs and increasing revenue streams, but also significantly boost British exports to what will soon become a trillion-dollar industry.
What action should the Government take to encourage investment into the industry and how much is needed?
There are many investors keen to finance AD and biogas. There was also support announced in the last budget announcement, including the Government’s intention to treble the proportion of biomethane in the gas grid by 2030.
Recent deregulation of the water industry, as part of Ofwat’s Water 2020 Strategy, has promoted new markets in bioresources from sewage and water resources to drive innovation, efficiency and greater resilience. The market for sewage sludge has a number of benefits. It is expected to encourage risk to be managed in the best place and the better deployment of skills and expertise to facilitate economies of scale, to extend the range of feedstocks utilised and to encourage a more efficient use of assets.
Why do you think anaerobic digestion has not been widely embraced and what do you think would help to encourage this?
AD is a far more complicated technology to build and operate than solar or wind. It doesn’t just generate green gas, but also treats waste - a process that captures harmful greenhouse gases and produces biofertilisers. With diverse feedstocks such as sewage, food waste, manures, slurries and crop residues, building the industry requires the involvement of multiple government departments, as well as multiple regulators.
As biomethane emerges as the ready to use renewable fuel to cut emissions in some of the hardest to decarbonise sectors, the policy rationale to support the sector is strong. ADBA is calling on the Government to implement better cross-departmental coordination to develop complementary policies and support mechanisms for AD, and recent discussions with officials suggest that there are positive improvements in this area.
Other asks from ADBA include immediate support for renewable heat beyond 2021; commitment to the Renewable Transport Fuel Obligation (RTFO) beyond 2032; targeted innovation funding for key aspects of the industry; setting up of organic waste hierarchies with AD named as their optimal recycling technology; development of a renewable biofertiliser obligation and support for local circular economy projects that use AD to transform waste into local heat and power.
It is also clear that the general population is not yet fully aware of the huge potential AD represents for their country, as well as their local communities. Education and public awareness about the wide-reaching benefits of AD will help overcome the current barriers by empowering people to hold their political representatives to account when delivering energy, transport, agriculture and a waste system that must meet the sustainability requirements necessary for the climate decade.
How does ADBA encourage technological innovation in the industry?
We actively engage with innovative projects that seek to improve any aspect of the AD industry and overcome the barriers that inhibit the sector from reaching its full potential. Using our extensive network of members, we connect academic and industry professionals to discuss innovation and ensure new technologies effectively advance the industry. Our expert team further engages with stakeholders through regular site visits and events, providing us with a comprehensive understanding of the sector and its needs.
Our policy team also liaises with government funding initiatives (e.g. Innovate UK) and universities to highlight industry needs and to encourage the funding of relevant projects.
How will anaerobic digestion help the UK reach its goal of net zero by 2050?
AD is already reducing the UK's greenhouse gas emissions by 1% annually. With a fully deployed infrastructure and optimised collection of the organic wastes made available for AD treatment, the industry could cut emissions by 6% as early as 2030, delivering 30% of the country’s legally binding carbon budget for 2030.
About the Author
Charlotte Morton is the Chief Executive at the Anaerobic Digestion and Bioresources Association and World Biogas Association. After practising law for 10 years, Charlotte was asked to establish the business side of the ADBA in 2009, where she saw the potential of the biogas industry to deliver huge value in the UK, and most recently, to help the Government achieve its Net Zero Goal. Charlotte is also on the board of Green Gas Trading Ltd, which runs the Biomethane Certification Scheme.