[Stoves] Characteristics of biochar was Re: [biochar] grassifier & cedar chip char

[Josh Kearns]

Crispin (or others) can you clarify this a little more - do the
Glaser-Steiner wood gasifier and BBQ charcoals test high for PAHs because
of post-manufacture additives? With BBQ charcoal, that could be lighter
fluid, which could be naptha (-lene)?

Also, they reference an EPA method for PAH determination. Would that
involve some kind of solvent extraction? If so is it an environmentally
relevant analytical method? I assume folks have seen this paper:

http://www.ncbi.nlm.nih.gov/pubmed/22321025

suggesting leaching of PAHs and dioxins from biochars should not constitute
an environmental problem.

Thoughts?

JK


On Wed, Feb 6, 2013 at 2:35 PM, Crispin Pemberton-Pigott <
crispinpigott at gmail.com> wrote:

> Dear Tom****
>
> ** **
>
> Thanks for that:****
>
> ** **
>
> http://www.bacatec.de/dl/Ge09_Glaser-Steiner_engl.pdf****
>
> ** **
>
> “A further criterion for the quality of biochar is the lack of
> contamination with both inorganic****
>
> (e.g. heavy metals) and organic contaminants (e.g. polycyclic aromatic
> hydrocarbons (PAH),****
>
> dioxins etc.). In this study, we could only evaluate polycyclic aromatic
> hydrocarbons (PAH,****
>
> Fig. 4). Although chars from wood gasification are within the elemental
> composition and the****
>
> black carbon thresholds, they exhibit extremely high PAH contents (Fig.
> 4). Therefore, they****
>
> are not suited for soil amendment and thus, they cannot be classified as
> biochar. Surprisingly****
>
> high PAH contents were also measured in the barbeque charcoals (Fig. 4)
> while all other****
>
> investigated chars had low PAH contents (Fig. 4).”****
>
> ** **
>
> Well, there’s a kick in the head. Why not? Because of chemicals
> manufactured in the process that were not there in the original fuel. That
> may explain a lot to some experimenters.****
>
> ** **
>
> Regards****
>
> Crispin****
>
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-- 
Josh Kearns
PhD Candidate, Environmental Engineering
University of Colorado-Boulder
Visiting Researcher, North Carolina State University

Director of Science
Aqueous Solutions
www.aqsolutions.org

Mobile: 720 989 3959
Skype: joshkearns
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