[Digestion] coffee grounds

[Terrence Sauve]

Hello Wayne,
There is an expert in coffee grounds on this grouplist, but I'll ask
you similar questions. By the way, the coffee ground are an
interesting feedstock to play with.
Is the reactor built yet? What are the other specs like the type
(CSTR, or sludge blanket) mixing and heating mechanism. Is it a dry-ad
or liquid system?
It will have an impact on the organic loading rate and hydraulic
retention time, parameters that you'll have to get comfortable with in
the future. Get your hands on a convection oven if you can to do
in-house dry matter analysis and ship to a lab samples for organic
matter.
Also, do you have receiving pits or other mixing tanks and what brand
- type of mixers are installed? Can you store some of them? You
mentioned sugar beets (the tops I imagine) do you have a bunker
(horizontal) silo where you can store the substrates year round?
Pig manure will be great to balance your moisture content and add
enough nitrogen in case you would be receiving carbon based substrates
only.
I would recommend to get a load of each substrate and send it to a
wastewater or env. lab to check for parameters discussed in AD
literature or other AD manuals from EU. Ask the farmers or haulers if
the substrates varies in dry matter or organic matter throughout the
year and the debris and grit that would accumulate at the bottom of
mixing tanks and reactor.
Keep yourself enough of the good substrates to make yourself a basic
recipe and then you could add on to the seasonal substrates when they
come.
'Clean' canteen waste is great, specially if you can get your hands on
the waste fryer oil, but a pain to handle and clean for such a small
reactor size.
Also verify with local environmental authorities if any substrates are
labeled as wastes. You may have issues later on. Also invite your
neighbors to open houses and get ready to safely accept guests for
demonstrations.
I'm curious, what will be using the biogas for from the 10m3 reactor?
Best case is you can get at least twice the volume of the reactor in
biogas per day which would amount only to about 10 m3 of methane per
day, enough to probably keep the reactor up to temperature and store
the excess heat in a hot water storage tank.

We'll be waiting for the coffee expert advise soon!
Terrence


On 8/2/12, digestion-request at lists.bioenergylists.org
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