That said… there are numerous high solid AD technologies out there and if the goal was to use manure as a resource rather than a problem, the digestate has a higher value for nutrients (conserves nitrates and nutrients are in a bioavailable “mineralized” form) as opposed to biochar where the nutrients that haven’t been volatilized are left in an immoble form. Though pyrolisis does make manure “disappear” which is more attractive to animal husbandry operations than high quality organic fertilizer (unfortunately IMO).

You are absolutely correct in that this is a totally misunderstood technology and that it is not a “sexy solution” to renewable energy or waste stream reduction issues. Having said that, I find it to be a very simple solution to one facet of pollutants converted to energy. Recycling of Ag waste on-site is very efficient as well as making a strong financial case. Ontario Province attitudes & incentives could be applied to more U.S. Ag & feedlot operations and create new sources of clean domestic energy not to mention, a whole new creation of U.S. jobs that could not be exported.

It sounds like a potentially great concept that I for one, would explore for development possibilities. Also, the Pyrolosis Systems can have a place for voluminous & municipal waste situations. I am interested in more debate on these issues.

Keep up the good work!

Trying to make these animal factories sustainable is akin to trying to make coal clean — which is to say it cannot be done.

I remain convinced that anaerobic digesters fit very well on smaller scale operations where the effluent can be more easily stored and used on surrounding fields as needed and that for these types of operations they make better sense than pyrolysis systems. While I agree that the biochar produced by pyrloysis is much more compact this is not a determining issue — IMO — on small to medium scale operations. The effluent from a ADS is much easier to store and handle than raw manure and the much of the fertilizer value is lost in the process of thermal decomposition.

Sustainable agriculture seeks to close open cycles and recapture as much value as it can from what were waste streams. It also seeks to be as energy efficient and other external input efficient as possible. This is the crux of sustainability and will become increasingly determinant as energy and resource commodity prices continue on the long term trajectory of ever increasing price due to increasing global scarcity of available supplies.

Although it may not seem like it I do happen to think that pyrolysis is a good green technology — where applicable. I see it being particularly applicable for recovering energy from and for carbon capture (i.e. with the biochar) for waste streams that are not suitable for anaerobic digestion, because they contain excessive levels of pollutants that would make the resultant effluent and solid remnants unsuitable for use as re-inputs into agricultural systems. A lot of urban generated waste streams fall into this category, because they contain a lot of organic pollutants that can be decompsed by pryloysis, but not by AD.

If the source waste stream feed stock is contaminated with heavy metal pollution it is my understanding that these heavy metals remain in the biochar making it unsuitable for use as a soil additive unless these meals can be removed. And that this is a problem with a lot of municipal waste.

Manure management is the number one problem associated with large dairy, swine and other animal operations. How exactly does one store hundreds of thousands of gallons of digestate? It is my contention that pyrolysis does more than just reduce the huge and unmanageable volumes of manures. It produces a sterile material with most of the nutrients still present. It is dry, so can be economically transported much further than digestate. As a “terra preta” material, biochar will loosen denser soils and retain water. And lastly, it can be field applied any time of year, unlike manures.

This post was mentioned on Twitter by GreenJobs: RT @greeneconpost Making the Case for On Farm Anaerobic Digesters: Anaero.. http://bit.ly/3de4wu
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One of the key ideas underlying the movement towards sustainable agriculture is the notion of closing loops that is in capturing and re-cycling valuable co-products from what are currently treated as waste streams. As you point out pyrolysis does have the advantage of significantly reducing the volume of the biomass being processed by thermally decomposing it. In instances where the biomass is contaminated with toxic components I think that pyrolysis is the best means of re-covering energy and (especially in high temperature systems) destroying many of the organic toxics such as pesticide residues etc.

However I disagree that pyrolosis is always a better answer as you seem to imply. When the feedstock is relatively free of toxins — i.e. pesticide residues, antibiotic residues, or other non organic pollutants — the large volume of co-products produced by AG systems is a valuable fertilizer and the solids residues when composted are a marketable product — can be sold to landscapers for example.

I think there is room for both pyrolysis and for Anaerobic Digester systems and the relative merits need to be weighed on a case by case basis.

Additionally, digesters and their bacteria, are a finicky breed. A sudden drop or rise in the operating temperature can ruin a processing cycle.

My company manufactures an integrated pyrolysis and conventional engine/generator set system that not only addresses the problem of overall manure volumes, but generates much higher power capacities while also creating biochar and oils which can be sold. We believe that our solution represents a significantly better means of manure processing and disposal than anaerobic digestion.

http://www.randaenergysolutions.com

I am impressed by the support for on farm anaerobic digester systems and the well thought out provincial government programs of Ontario, Canada. One aspect that they have addressed and that in my opinion should be a model for analogous US programs is mandating a clear market base for selling surplus electricity up onto the grid. The Renewable Energy Standard Offer Program (RESOP) — in Ontario province — gives biogas electricity producers the option to sell or replace power at fixed rates for a period of 20 years. At the time of writing, the value of the power is approximately 11 ¢/kilowatt hour (kWh) for non-peak periods and 14.52 ¢/kWh for peak periods. This guarantee makes it much easier for farming operations to raise capital by providing a fixed rate guaranteed market for any electric power that is produced.

Are you aware of any similar programs in the southeast region of the US, which you are most familiar with? I have looked for incentive programs that are tied to the carbon offset market, but have not been able to find any. If you know of any existing tie ins I would love to hear about them.

As I alluded to in my post one of the problems that anaerobic digesters face is that they are poorly understood by the public and by policy makers and the technology is not sexy like say solar power is and is thus often relegated to the back of the policy agenda. I am on the lookout for finding grants, tax incentives such as accelerated capital depreciation, training programs, and market guarantees similar to those existing in Ontario, Canada. Bioreactors are an important technology for making many types of farming operations more sustainable.

The revenue stream for these systems basically has three components: on-farm savings (cost offsets), electricity sales, and renewable energy/carbon credits. In order to achieve the electric sales and credit revenue streams, the digester system has to be “sold” to the utility and its regulator as having value in those respects. This requires a lot of paperwork and, ideally, an economy of scale by bundling multiple systems together.

Who’s doing work to help address this issue?