Bad News for Agricultural Use of Anaerobic Digestion in Agriculture - DEFRA 2005 Report is Discussed

New Web Page about the Agricultural Use of Anaerobic Digestion for Livestock Manures and Slurries

The Anaerobic Digestion.Com web site has [so far] been short on information on Agricultural AD. This actually only reflects the position in the UK which had more on-farm AD units in operation during the mid-1990s than it does now.

Probably the most authoritative recent study on the viability of anaerobic digestion is the report prepared for the Sustainable Agriculture Strategy Division of the United Kingdom Department for Environment Food and Rural Affairs (DEFRA).

This is not a new report as it was published in October 2005, however, we do think it worth studying for anyone interested in utilising this abundant source of on-farm AD and Centralised Anaerobic Digestion (CAD) feedstock.

The report is really quite heavily negative about the economic vialbility of this form of AD, under the then, and current, regime in which the UK government is not providing direct financial support for AD.We would argue that:-Our view at Anaerobic-Digestion.Com is that there is a very good case for additional government investment in on-farm AD.

There is a significant win to be found from the reductions in greenhouse gas emissions, and the necessary £143 lifetime costs estimated for the first twenty plants in this report would surely deliver big bonuses in the development of the technology. If done well this investment would act as the seed corn for the mature development of the Anaerobic Digestion industry at which time costs would surely plummet.

Were we not at a similar stage with wind turbines no more than ten years ago?Surely many of us can remember that wind turbine rotor blade failures featured heavily in the news. The doubters were saying that the reliability problems being experienced in that industry at the time were close to insoluble for such highly stressed and massive blades.

Yet now who even mentions such problems?

The parallels are all around us which show us the benefits of strategic investment and the potential in Anaerobic Digestion. Let us see some leadership from our politicians who should by now realise that the public demand for action on carbon emissions is high.

The public also increasingly want to buy renewable power for their own domestic use, and so the provision of financial incentives for Anaerobic Digestion would help in this and other many ways.

Visit our new web page on the Agricultural Use of Anaerobic Digestion here.

Anaerobic Digestion Can Give a High Investment Return, Operator Claims

Here is a summary of a news item put out during the autumn last year (2006), for any that have not heard of this:-

The operator of one of the first full-scale anaerobic digestion plants to treat household waste in the UK has revealed a "strong economic return" for its initial investment.

Greenfinch Ltd, which opened its plant in South Shropshire in mid-2006, has stated that that plants processing 15,000 tonnes a year could cost in the region of GB Pounds 2.2 million to set up, but these can be profitable.

The company's CEO, Michael Chesshire, revealed to an audience in London that every year an anaerobic digestion plant like his can bring in earnings of GB Pounds 300,000 for electricity generated from biogas as well as GB Pounds 675,000 in gate fees for taking in these wastes.

The news was revealed to delegates of a Composting Association seminar in South London, and Michael Chesshire went further to say; "There is a general misunderstanding in the waste industry over the cost, size and nature of anaerobic digestion. Not only is profitability possible, returns can be strong.

A GB Pounds 2.2 million plant, which takes 15,000 tonnes of waste a year, costs only GB Pounds 350,000 a year to operate.

Michael Chesshire the CEO of Greenfinch, the company which designed, and managed the construction stage of the DEFRA/WRAP funded full-scale household green waste/food waste anaerobic digestion plant now operating in South Shropshire (UK) as a technology demonstration project, said that there are also potential uses for the products of the process which if sold can further improve profitability.

Anaerobic Digestion Found to Hold Many Advantages to Agriculture

As the US nation looks to agriculture for renewable fuels from crops and other sources, many researchers are realizing that there are developing countries such as China and India which have already have developed a manure management system that produces energy, saves valuable nutrients for fertilizer, and provides great benefits in improved sanitation health and bio-security for those using it.

It has even been in use on some farms in the US, although until energy prices began to rise recently it was not even close to being economically viable.

That system is anaerobic digestion, and furthermore it can cut greenhouse gas emissions and stops offensive odours

Without proper management, animal manure can get into groundwater supplies, and odour problems can produce a nuisance for nearby residents, and this is happening more frequently as dairy and pig farm sizes grow and urban sprawl moves into farmland.

University of Florida researchers say that,

The key to our waste management system is a natural biological process called anaerobic digestion that relies on microorganisms to transform animal manure into methane gas.

Anaerobic digesters, which process waste under oxygen-free conditions, are different than conventional aerobic systems that use oxygen to treat the waste. Anaerobic digesters can, the same researchers suggest, process five to 10 times more waste than aerobic systems. Because the waste is enclosed to keep oxygen out, anaerobic digestion keeps odors in.

With anaerobic digestion, the methane produced can be used to heat water or generate electricity, eliminating greenhouse gas emissions that contribute to global warming. To demonstrate the technology at a working dairy farm, a large-scale anaerobic digester at University of Florida's 500-cow Dairy Research Unit in Hague, Florida is now generating biogas from manure flushed from animal barns and milking parlors.

The patented waste treatment technology is being made available for licensing by University of Florida's Office of Technology Licensing.

About 40 cubic feet of methane per day can be produced from the waste of each dairy cow, these researchers estimate.

The anaerobic digester processes manure from the large volumes of water used to flush waste from animal holding areas at the dairy. Because manure flushed from these areas is so diluted by water, only two types of anaerobic digesters are practical for dairies – covered lagoons and fixed-film digesters, researchers.

In covered lagoons, which are less efficient than fixed-film anaerobic digesters, the digestive bacteria float around, making only random contact with the manure particle

, this problem is not seen in fixed-film reactors it is claimed.

Generally, the fixed-film design is suitable for any livestock manure that is diluted with water for transport or processing, such as dairy and swine waste.

First, by capturing biogas, anaerobic digestion can reduce natural emissions of methane, a potent greenhouse gas. Second, when anaerobic digestion produces renewable fuel to replace fossil fuels such as coal, oil and natural gas, production of carbon dioxide from burning
those fossil fuels is avoided.

The anaerobic digester also lowers the levels of pathogens; starvation and competition with other microorganisms help kill pathogens that might be in the manure.

Just like many researchers across many countries, the potential for anaerobic digestion to solve several major problems, is remarkable.

Could we really have the possibility of developing a sustainable option for dairies and other livestock operations that produces renewable energy and protects the environment? Many think so, and governments and investors will do well to look seriously at encouraging the further development of anaerobic digestion technology.

Based upon an article by University of Florida, published February 2006.