We titled this “Anaerobic Digestion Biomass“, and not the more obvious “Anaerobic Digestion of Biomass”. That's because our intention is to talk about biomass as a resource, which is largely unused, and can become a huge source of energy, fertiliser and fibrous material for use after anaerobic digestion, not only a soil improver, but also to make building materials, bedding material for cattle, etc.
Researching available biomass feedstocks to use as Anaerobic Digestion Biomass is the starting-point for designing all anaerobic digestion plants. At this point it is useful to make the point that there are far more categories of biomass which are suitable for use as an anaerobic digestion biomass feedstock, than just the traditional textbooks would have you believe.
An idea of the huge scope in the available categories of suitable anaerobic digestion biomass, can be see below. The following table of biomass resource categories, is from a US report entitled, “Biomass As Feedstock For A Bioenergy and Bioproducts Industry: The Technical Feasibility Of A Billion-Ton Annual Supply”.
From that graphic above you will see that biomass is a largely untapped resource, with a great deal of potential for the future development of anaerobic digestion.
The Scale of the UK Anaerobic Digestion Biomass Resource Which is Being Wasted
According to the Anaerobic Digestion and Bioresources Association (ADBA) during their world Biogas Expo in July 2017, there are 10 million tonnes of food waste and 90 million tonnes of manure produced in the UK each year.
Yet anaerobic digestion plants only use 2.4 million tonnes of food waste, and approximately 2 million tonnes of manure.
Perhaps the best way to demonstrate that there is a vast untapped resource is to provide just one example, and to do that it is not necessary to look very far at all. In fact, this resource will be at the end of the front drives of the homes many people reading this now. What is it? It's grass verges…
“UK Grass Verge Cuttings – If Collected Nationwide Would Provide an Extra Grassland Area the Size of Essex”Dr Nick Cheffins, Managing Director of Peakhill Associates, provided a presentation at the above ADBA event during which he likened the national roadside grass verge biomass resource to an additional productive area the size of Essex, if just 50% of the UK's verge mowings were collected.
Imagine the huge additional biomass bioresource that the nation's road verge's would provide if all were mown, and the cuttings were collected and digested.
Watch our video below about this to get a quick introduction to this subject:
Lincolnshire County Council is the leader in the UK for verge grass cuttings collection. Agriculture in Lincolnshire is highly intensive, and that means that the species of the once diverse grasslands are under heavy pressure of extinction.
For many species in large areas of the county these original local plants are only to be found in grass verges that are mown after the seeds have set each year, with the cuttings removed. Unlike some European countries cuttings removal is not a legal requirement when the Council cuts the verges.
Unfortunately, cutting has been curtailed due to austerity funding post-2007, and the banking crisis. The result of local government funding reductions is less frequently mown verges, and rank growth. The result of this is that the cut mowings tend to compost themselves in-place, and that raises the fertility of the verges. Rank growth follows and that threatens delicate grassland species which are being squeezed out.
The Council has been looking at new ways to fund grass-cutting, to protect the ancient local grassland species, without placing the burden on ratepayers. It is their hope that using their verge cuttings as an anaerobic digestion biomass, paid-for as a feedstock used by local network of biogas plant operators, will pay for the preservation of the natural grass flora, and the fauna that lives in it.
The Council's work to bring about species preservation through grass mowings collection and delivery to anaerobic digestion plant, in this way, is illustrated in the following article excerpt originally published on the BBC's website:
Lincolnshire County Council is using a special machine to cut and collect grass cuttings ready for anaerobic digestion. Delegates from councils across the country have been to see how this pilot scheme works. The scheme is monitoring biogas yields, biodiversity impacts and the costs of harvesting grass in this way.
The cuttings are taken to a biomass plant at Scrivelsby near Horncastle and used as fuel.
Ultimately if the pilot scheme is successful the council could get up to 10 of these machines. The council has about 4,000 miles of grass verge to maintain.
Dr Nick Cheffins, who helps oversee the trial, said:
“It could be a renewable power source. We sell electricity to the grid and use the heat also produced for various agricultural processes”.
The scheme was looking to get enough data to produce a “tool-kit” for other interested councils, he added.
The grass is collected to eventually produce electricity. Through anaerobic digestion, which is a process by which microorganisms break down biodegradable material in the absence of oxygen.
Organic material such as manure, crops, grass or slurry is put into large containers. Once this material breaks down it produces biogas such as methane. The methane can be converted and fed into the National Grid.
Councillor Richard Davies said:
“This is a first for a local authority. It's early days, but we think it's worth testing it out in the real world.”
Mr Davies said removing the cuttings from the verges helped to protect wildflower growth and slow down the rate of grass growth.
“It makes sense from both an environmental and economic point of view”, he said.
Mark Schofield of Lincolnshire Wildlife Trust said the scheme could;
“throw a lifeline to grass land” and change the way grass verges were managed.”
The scheme is being run with support from the Lincolnshire Wildlife Trust and Leeds University. … via Grass cuttings used to produce electricity
Peakhill Associates Ltd delivered the above Study on the “Utilization of Anaerobic Digestion to sustain the harvesting of road verge biomass”, on behalf of Lincolnshire county Council (LCC). For more information on the study visit Peakhill Associates here.
Is Your Company Sitting on a Hidden Asset of Suitable Anaerobic Digestion Biomass?
There are many companies who possess suitable anaerobic digestion biomass, which is a hidden asset they are unaware of, and have yet to carry out even the most basic reviews of their company's product and waste streams as they exist currently.
If those companies were to re-assess what they are now very often treating in industrial effluent treatment plants, at very significant expense, could become an income stream using their own free (to them) biomass feedstock, if they were to invest in a plant to produce biogas.
To highlight the opportunities that companies which currently produce a lot of waste biomass, often called “high BOD (or COD) industrial effluent”, such as those in the food processing industry, we have produced our own video.
We have embedded that video below. If your company is one such company treating your valuable biomass as a waste and not digesting it, we suggest that you watch the video below, and maybe after watching, you should also follow the link to our full article below this video on utilisation of suitable anaerobic digestion biomass:
To see our more in-depth article about the use of waste biomass to create biogas, click here.