[Terrapreta] Pottery Shards and Terra Preta

[Kevin Chisholm]

Dear Lewis

Very interesting observation.

Biofilters are very common in aquaculture and aquaponics.  Ammonia is 
very toxic to fish, so it is necessary to find a way to remove ammonia 
from recirculating fishwater systems. As you rightly point out, the 
nitrifying bacteria that convert ammonia to nitrite and nitrite to 
nitrate require a substrate on which to habitate. These bacteria tend to 
form a slimy coating on surfaces. Biomedia surfaces are only effective 
when they can support living bacteria.

What seems to happen is that if the pore size of the media passages is 
"too small," then the nitrifying bacteria cover the passages and kill 
any bacteria within the passages by suffocation and starvation. 
Biofilter media manufacturers and designers generally recommend a 
minimum passage size of about 1 cm to maximize flow conditions and 
surface area, and minimize the potential for blockage.

Char has a pore size that is several orders of magnitude smaller. It is 
quite likely that these tiny pores will get "slimed over" with 
nitrifying bacteria, sealing off the large "internal area" of the 
charcoal, and killing the bacteria within.

If this was the case, then the large internal area of the char would be 
unavailable to participate in soil reactions. On the other hand, with 
alternating "life and death periods", the effect may be to bring 
nutrients to the interior of the char particle on a regular basis, 
making the char highly active.

This opens up the possibility of some interesting possible TP operating 
mechanisms.

Kevin


MMBTUPR at aol.com wrote:
>           from          Lewis L Smith
>
> This thread, especially the pictures of fungi and microbes on and 
> within charcoal, which Tom unearthed a while back,  reminds me of a 
> development which took place here in Puerto Rico some time ago and 
> which may be relevant for the understanding of how terra preta works.
>
> Many years ago, our largest rum distillery, that of the Bacardí 
> Corporation in Cataño, used to dump its distillery slops into the 
> Atlantic Ocean through a long outfall. At some point, the US 
> Environmental Protection Agency staid "stop". So with the aid of a 
> university from the state of Florida, Bacardí scientists developed an 
> anaerobic digester to convert the slops into a biogas and other useful 
> products. This digester eventually  came to supply the heat necessary 
> to produce all of the low-pressure process steam used by the distillery.
>
> Now anaerobic digestion is typically a process in which three 
> different kinds of microbes inhabiting a slurry, in succession "snip" 
> big molecules into small ones. At some point, the chief scientist [ 
> whose name escapes me at the moment ] figured out that the microbes 
> would do a better job if they had more surface on which to "sit" while 
> they "snipped". So he and his associates devised a honeycomb type 
> structure and inserted it in the digester. Digester productivity 
> improved substantially.
>
> Although the chief scientist has retired, the improved process 
> continues in use today. In fact, use of the related patents is 
> available under license. And I believe that one may even still visit 
> the digester control room, as I did years ago.
>
> The point of interest here is the concept that microbes do their work 
> better when attached to surfaces than when they are floating around in 
> a liquid or semi-liquid. This may help to explain the increase in soil 
> productivity obtained by creating terra preta and perhaps even the use 
> of shards, which of course adds to the surface area available to 
> microbes within the terra preta.
>
> What does the List think ?
>
> Cordially. ###
>
>
>
>
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