Getting More Out of Anaerobic DigestionThis week we have news from the US, Italy, and the UK. In one way or another all are seeking to get better biogas yields and more out of their involvement in the anaerobic digestion process.
Video Transcript:The first two articles highlight the many and varied ways in which US academia is following on from that in Europe and many other nations, and discovering many new largely un-researched topics, in anaerobic digestion and biogas, which they are now exploring.
This enables them to work with AD Plant operators to improve yields and reliability, providing educational opportunities for their students, and a service both to their own biogas installations and outside to their local communities.
Also in the case of Michigan University they are conducting research in partnership with the University of Costa Rica, which involves evaluating operating at higher temperatures to produce pathogen-free residue. An interesting possibility here would arise if they were successful. That would mean that digesters could then be operated without the need for additional expensive energy-consuming pasteurising equipment.
In the final paragraph of the Michigan University article extract we are told that assisting the Detroit Zoo, which is now in the early stages of developing a dry digester using food and animal waste, which conveniently leads us into the penultimate article of the week.
That article informs us that HZI is to build Italy’s fifth Kompogas Dry Anaerobic Digestion Plant. Biowaste and green waste will be processed using dry anaerobic digestion and composting. The biogas produced will be upgraded to valuable biomethane, and the digestate will provide nutrient-rich liquid fertiliser and high-grade compost for use in agriculture.
Last, but not least, our final UK article explains in a frank manner why so much university research is being done on anaerobic digestion globally, in an article titled: "Getting More Out of Anaerobic Digestion". That reason is the reality of poor performance, especially from many UK food waste AD plants. The author refers to many instances where plants are failing to achieve standards which would be routine within more mature industries.
Some of the barriers which are suggested as preventing better digester performance, are multiple and variable quality feedstocks, over-feeding digesters, and rapid changes in feed material quality.
Nevertheless, the author points to rapidly improving average UK wide load-factors, so the solution to low biogas outputs, does appear to be on the horizon for the UK food waste anaerobic digestion industry.
Now scroll on down and read the article excerpts described above. Also click through our links, to read the full article versions of those which are of particular interest to you:
1. US College Turns to Anaerobic Digestion to Reduce Carbon Footprint
Middlebury College has entered into a partnership with Goodrich Family Farm in Salisbury, Vermont, Vanguard Renewables of Wellesley, Massachusetts and Vermont Gas.
The new agreement will see Vanguard Renewables construct, own and operate a facility at Goodrich Family Farm which combines cow manure and food waste to produce renewable natural gas. Gas produced in the anaerobic digester will be transported by a four mile pipeline to Middlebury College’s main power plant. The college has agreed to buy most of the new facility’s output.
“We are constantly looking at new ways to make our energy sources more sustainable and diverse, and the digester project is a great opportunity to do that,”
said David Provost, executive vice president for finance and administration at Middlebury College...
“In 2016, the College reached its goal of carbon neutrality. We want to maintain that goal and keep improving on it. The digester will enable us to further decrease our use of carbon-based fuels.”
“The digester offers help with many of the challenges we face as farmers,”
said Chase Goodrich, who is among the fourth generation of his family to operate the farm.
“We want to diversify our income sources and find new ways to be environmentally friendly. Here in the Champlain Valley, we’re particularly aware of efforts to reduce phosphorus runoff into Lake Champlain.”
Currently in the permitting phase, when completed the anaerobic digester facility will produce the largest amount of renewable natural gas of any facility in Vermont. It will process 100 US tons of manure from the farm and 165 tons of organic food waste per day.
According to a statement, Vanguard plans to source the organic food waste from local and Vermont-based food manufacturers including Cabot Creamery. via US college turns to anaerobic digestion to reduce carbon footprint | Bioenergy Insight Magazine
2. Michigan State University - Leading the Way With AD Facility, Research Feedstocks, and Provide Technology Transfer
Michigan State University, in East Lansing, Mich., is leading the way with a facility that processes between 20,000 and 24,000 tons of food waste annually to generate 380 kilowatts of electricity every hour for the campus, up to 2,800,000 kwH annually.
But Michigan State’s influence stretches far beyond its campus where ongoing research in Costa Rica and other South American countries is exploring methods to address challenging waste streams specific to certain regions.
On campus, a lot has changed since the university built its current domestic plant in 2013...
Currently, the university is exploring ways to extract better value from [...] digestate. The plan is to concentrate the nutrients in this digestate into smaller volumes of fertilizer, which can then be used on campus cropland and private farms. The process would not only increase product value, but reduce waste in discharged water, consequently cutting gallons that need to be hauled...
Michigan State’s earliest involvement with AD reaches back to 2003 when it secured a grant to build a full-scale plant on a local dairy farm. In 2008 it created an AD research education center, which is a private- public partnership to support the developing industry. The focus is on helping municipalities, other waste generators, and investors to understand how the technology can be used for renewable energy and waste management.
In addition to providing [an AD research education center for] their stakeholders with training and technical assistance, the university’s researchers evaluate feedstocks. They have looked at more than 1,000 waste products from paper plates to grass cuttings to determine biogas potential.
Its work internationally is driven largely by the goal to learn more.
“If we go global we get to stay at the forefront of technology development,” Kirk says. “If technologies are deployed in other parts of the world, we get to see them early and may be able to bring them to the U.S.”
Research in partnership with the University of Costa Rica involves evaluating operating at higher temperatures to produce pathogen-free residue.
Facilities are using fruits and vegetables from distribution centers and have used coffee wastes as feedstock. Currently the work is focused on transforming pineapple liquid waste to energy.
“While Costa Rica’s pineapple industry is important to the local economy, there is increasing concern about impacts on soil, water, animals, and persons,” says Werner Rodríguez-Montero, head of Fabio Baudrit experimental station, University of Costa Rica. “One hectare generates approximately 350 tons of organic wastes. In time we believe the technology will help us manage this waste as well as that from other crops in Costa Rica and beyond.”
While research involving Michigan State was concentrated in Costa Rica, Nicaragua and Panama were also involved.
“Through this relationship with Michigan State we developed a regional network to transfer anaerobic biodigestion technology from Costa Rica to other countries facing similar problems and in need of sustainable tropical cropping systems. This infrastructure is the only one existing in the region to do research at this scale,”says Rodríguez-Montero...
3. HZI to Build Italy’s Fifth Kompogas Dry Anaerobic Digestion Plant
|Copyright Hitachi Zosen Inova|
4. Getting More Out of Anaerobic Digestion
The best measure for performance is load factor, or running time. Recent years have witnessed phenomenal improvements – even six years ago, average load factors sat at just 46 per cent, compared with 73 per cent in 2016. However, with the most efficient operators reporting levels of 98 per cent, many in the industry still have a long way to go.
The biggest barrier is feedstock. Despite murmurs from central government on separate food waste collections for all households in England – in line with Wales and Scotland – collections currently lie at just over 50 per cent. Similarly, the bulk of commercial food waste collected does not make it to AD either.
However responsibly food is prepared, an element of food waste will always remain, and once reduction and redistribution have been addressed, waste management firms need to actively encourage separate collections and build relationships with AD businesses to ensure food waste meets its potential...
Improving AD Plant Feedstock DosingOn the ground, improved feeding regimes have a direct impact on gas produced. AD is all about maintaining good biology, and good biology relies on consistency.
This means sticking to one type of feedstock or, where that is not possible, giving the bacteria time to adapt....
Recent changes to renewables incentives mean that agricultural plants coming onto the market will need to include a fraction of food waste in their ration.
Based on the current climate, it seems likely that unless waste managers and local authorities do more to drive material to AD, feedstock shortages, and under-performance, will become increasingly acute. via Getting more out of anaerobic digestion
Please Like, subscribe and leave a comment. Also - Join our mailing list!