[compost_tea] Re: Re: Eastman vermi report

From: Kirk Leonard <kirk_at_oregonatural.com>
Date: Mon, 7 Jun 2004 17:18:03 -0700
Wasn't intending to propose vermicomposting for sewage sludge, but it
obviously works to EPA standards, and au contraire, Ted, vermicomposting can
be done on as large a scale as you have land to put under it and feed to
feed.  I've worked with two such systems, and there are several other ways.

Their quest was simply to test Eisenia for Class A biosolids pathogen
reduction, I think.  You wouldn't set up a facility like they did if you
wanted to do it on a continuing basis.  They used batch processing, and
you'd build for continuous flow rather than batch processing.  Large scale
vermicomposting is different from most composting in that respect.

1:1 is actually a low feed rate for continuous flow vermi systems.  Lot of
worms but not unusual.  1:1.5 is also not unheard of (for short periods) but
you plan on 1.5:1 in setting up a continuous operation.  2:1 is not
unusual - meaning 2 pounds of waste for each pound of worms, per day, or
whatever feeding period.  Depends on the feed stream.  Some people claim
even higher throughput.

If the worms die, you really screwed up, and yeah, you'd want a contingency
plan for that.  If there's not enough food or water, they lay eggs
("cocoons" of several eggs each, actually) and die (or migrate, yes).  When
there's food and water again the eggs hatch and they go right back to work.
So what a plant would do is not worry about not having food - they'll be
right there again as long as you left some material behind - literally
within a few days.

Worms are real easy to work with on any scale when the system is appropriate
for the feed stream, managed well, and covered - polyhouses work well most
places, but any kind of cover can work.

I suggest we take this offline if you want to talk more.  May already be OT?
I've been working on large scale vermicomposting for ten years, so I think I
know a bit about it...  I did find throughput exceeded what can be done with
composting, too, just takes some time to get there (unless you had Eastman's
worm budget, I suppose:).

If your 200,000 tons is 83% water, I could show you how to vermicompost that
continuously on less than 5 acres.  What would it take to compost or "cure"
it per current WWTP stuff?

Agree about inoculant oddness, but that's how chem-heads look at things, I
guess.  Un-naturally.  --  Don't want to imply authors of this study are
chem-heads. Not likely. Test protocol was chem-headed.

Worms are amazing.  I bet they and their critter crews will even disrupt
disruptors.

Got all the way through this and didn't even say USNOP rawmanureheads!  How
'bout that?

Kirk

> Date: Sun, 6 Jun 2004 16:06:21 -0700
> From: "Ted Peterson" <ted.peterson_at_tcsn.net>
> Subject: Re: Eastman vermi report
>
> One of the reasons this may be impractical on a large scale is that item
referring to amounts of earthworms per amounts of biosolids.  Let's forget
the innoculants right now.
>
> For the test, they used a ratio of 1:1.  There was approximately 3.6MTons
of biosolids and 3.6M tons of earthworms.  In subsequent tests, the full
scale, there were 1:1.5 biosolids to earthworms.  So we have a situation
where there are more earthworms per tonnage than biosolids.  If a WWTP were
to incorporate this type of methodology and the earthworms died for some
reason, they would be a the mercy of the provider.  If the plant chose to
raise the earthwoms, they would have a whole different set of problems.
>
> The work looks promising and it has long been known that earthworms, like
pigs, process human wastes better than almost anything.  I think the reason
nobody has pursued it is simply because the logistics of this on a large
scale of say 200M tons is not feasible.  The way WWTPs work is not
consistent.  There are all kinds of factors like weather and food types and
heat and acid, etc.
>
> In addition, what does the plant do with the worms when there are no
biosolids to process?  Seventeen percent solids is kind of jelly like.  This
means that unless there is a source of O2, there will be anaerobic areas.
Now, with a 1:1 or 1:1.5 ration, this may be moot but if something happens
to the worms, you have zilch.
>
> My ex business partner is the most knowledgeable worm person I have ever
met.  I asked him once why people didn't use earthworms to process biosolids
to class A.  His response was that it would take too long because even if
you get enough, they will eventually run out of food and leave.
>
> Now, this report was written in 1997. Endrocine disruptors were barely a
blip on anyone's radar at that time.  The biosolids being treated now are
loaded with hormones such as estrogen and I do not think there has been any
work done on worm and the processing of hormones.
>
> So again, the report looks promising and I am sure it works.  I think
logistically, it is still impractical for large scale operations.
>
> I would like to see the same experiment tried at a WWTP with little heavy
metals and one close to an industrial area with known heavy metals to see
how that panned out.  It seemed that the only interest here were pathogens
and the heavy metals were given little attention.
>
> I am always curious when innoculants are used.  It bothers me that they
couldn't get the biosolids certified as containing certain elements then
process from that.  To get the numbers they wanted, they had to artifically
innoculate the windrows. (Actually at 17% solids, there was not much
windrowing but bedding.  There must have been containers to hold the
material without runnoff.
>
> Anyway, that's my take.
>
> Ted Peterson
> EW/SOE






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Received on Mon Jun 07 2004 - 22:22:27 EDT

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