UTILIZING LOWER LIFE FORMS FOR THE BIOCONVERSION OF P U T R E S C E N T W A S T E and how this could dramatically reduce carbon emissions By Dr. Paul A. Olivier Suppose we were asked to imagine the best possible way to dispose of putrescent waste, to imagine a totally natural process that would affect an enormous reduction in the its weight and volume within a matter of just a few hours. Ideally this process should require no oil or natural gas, no gasoline or diesel, no coal or charcoal, no electricity or chemicals, absolutely nothing ‐ not even water. The process should be totally self‐contained and not emit a drop of effluent, and aside from a small amount of carbon dioxide, it should not produce methane or any other greenhouse gases. The unit housing this process should operate with the simplicity of a garbage bin. It should have no moving parts, and it should require very little servicing and maintenance, very little expertise or experience to operate. It should not emit offensive odors, but at the same time, it should drive away houseflies and other filth‐bearing flies. Since food waste would be rapidly reduced and recycled at its point of origin, it would eliminate altogether the collection, transport and land‐filling of food waste. Similarly the huge problems associated with accumulation of manure at pig parlors, dairies and poultry farms would be solved. This bioconversion process, however, should not demand the introduction of anything foreign or exotic. It should be powered by a creature commonly found throughout the whole of the Americas, and even though it may have lived alongside humans for thousands of years, it should not be associated in any way with the transmission of disease. In view of the wide variability of putrescent waste presented to it, this benign grub should possess one of the most robust digestive systems within nature. It must have the ability to thrive in the presence of salts, alcohols, ammonia and a variety of food toxins. Upon reaching maturity, this creature should be rigidly regimented by evolution to migrate out of its feeding chamber and into a collection bucket without any human or mechanical intervention. This self‐harvesting grub should represent a bundle of nutrients that should rival in commercial value the finest fish meal. Why not boldly insist upon the reintegration into the food chain of virtually all of the nutrients and energy contained within the waste? Is the bioconversion process described above nothing but a fanciful leap of the imagination? Hopefully as you read on, it will become clear that this process does, indeed, exist, and that it represents the fastest, cleanest, most efficient, and most economical way to recycle food waste, manure and all other types of putrescent waste. 1
The aagent chosen for this biocconversion process is thee larva of the black soldier fly (BSF), Herm
metia illucens.. This speciess of fly is indigenous to th
he whole of tthe Americass, from the south
hern tip of Arrgentina to B
Boston and Seeattle. Unlik
ke many otheer flies, BSF aadults do not go into housses, they do n
not have funcctional moutth parts, they do not eeat waste, do not come iinto contact they d
with w
waste, they do not regurggitate on hum
man food, and
d conseq
quently, they
y are not associated in any w
way with thee transm
mission of dissease. They do nott bite, botherr or pester human
ns in any way
y. The baasic bioconveersion numbeers associateed with this proceess are quite incredible, aand they are backed up an
nd confirmed
d by many deecades of intensive research
h in Americaa, Australia an
nd Asia. Each
h day BSF larrvae can digeest over 15 kilogrrams of putrescent wastee per square meter of feeding surface area (3 lbs//ft2). In the case o
of putrescentt waste of a llow cellulosic content, wee also witnesss a reduction
n in weight and v
volume that rreaches as high as 95%, aand under no
ormal conditiions, all of th
his takes placce within a period off less than 24
4 hours. Finaally, in the casse of rich sub
bstrates such
h as food wastee or pig wastte, we see thaat 20% by weeight of the fr
fresh waste b
bio‐
conveerts into fressh larvae. Thou
usands upon thousands o
of active larvae can be foun
nd in a putreescent nit, and in con
ntrast wastee disposal un
to red
d worms, theese larvae hav
ve the ability
y to eat and digest just ab
bout any ty
ype of fresh p
putrescent w
waste, includ
ding meat an
nd dairy prod
ducts. The m
moment the w
waste is depo
osited into tthe unit, the llarvae begin to eat it long before it beegins to rot aand vae, nonetheless, do smelll. But the larv
give o
off a distinctiive odor (nott offensive to humaans) that driv
ves y houseflies aand all other flies that aree a pest to hu
umans. away
After reaching maaturity BSF laarvae will craawl long disttances in search of an ideeal pupation Prepupal miggration initiaally appears tto be a rando
om search forr a way out o
of the waste. site. P
If a raamp of an up
pward inclinaation lies at tthe edge of th
he waste, thee larvae will m
make every effortt to climb up this ramp. IIf, at the sum
mmit of the raamp, an exit h
hole is provid
ded, the larvae will fall neaatly and cleanly right into
o a collection
n bucket. 2
Note that BSF larv
vae are totallly self‐harvesting. They aabandon the w
waste only w
when they hey crawl outt of the wastee and into a have reached theiir final maturre prepupal sstage, and th
ntervention.
collecction bucket without any mechanical or human in
BSF bioconv
version unitss (called biop
pods) are now
w being manufactured in aa medium den
nsity ndefinitely. A
A nominal 2‐
polyethylene that lasts in
he left), foot diameteer biopod (deepicted on th
weighing on
nly 14 lbs (6.4
4 kg), can process over a metric ton o
of putrescentt waste per year. A nominal 4‐fo
oot diameterr biopod, weiighing about 40 lbs (18 kgg), can proceess well overr five metric tons of putreescent wastee per year. Therefore, w
why should w
we go on colleecting and land‐filling ffood waste? W
Why should we allow manure to aaccumulate on farms in un
nmanageablee proportionss? Why do wee compromisse the health of birds and animals by rraising them
m in close o their wastee? Why do wee go on proximity to
pumping these creatures with antibiiotics? Why do wee eat the flesh of birds an
nd animals grrown under ssuch wretcheed conditions? All off this becomees even moree nonsensicall when we co
onsider the v
value of BSF llarvae. BSF larvae have a dry matter conteent of almostt 50%, and th
his dry matteer is incredib
bly rich in ntent of 34%. It has rough
hly the same nutrieents. It has a protein conttent of 42% and a fat con
valuee as Menhadeen fish meal v
valued at oveer $1,200 US dollars per tton. Of cou
urse BSF larv
vae emit a sm
mall amount of CO2 as theey eat and diggest putresceent waste, bu
ut 2
such an amount o
of CO is negliigible relativ
ve to what haappens when
n putrescent w
waste is dump
ped in landfillls or accumu
ulates in lago
oons. BSF larv
vae begin eaating putrescent waste the minute it is made available to them, long b
before anaero
obic or even aerobic bactteria have an
n opportunity to deegrade it. only do BSF laarvae preven
nt anaerobic bacteria from
m transforming waste intto methane, Not o
but th
hey also prev
vent the hugee release of C
CO2 that mesophilic or thermophilic b
bacteria would
d generate iff the waste w
were compostted. Furtherm
more BSF bio
oconversion generates faar less C
CO2 than even
n vermi‐com
mposting seen
n as an isolatted process, ssince red worms do not eat frresh putresceent waste but depend upo
on bacteria tto do an initiaal breakdown of waste. This iinitial degrad
dation of wasste by bacterria releases laarge amountts of CO2 into
o the envirronment and consequentlly is far from
m ideal. Howeever when laarval bioconv
version preceedes vermi‐composting, n
nothing could
d be more efficieent. The larv
vae capture n
nutrients longg before bactteria have haad a chance to degrade them, and the non
n‐putrescentt BSF residuee constitutes an ideal substrate for red
d worms. nt studies in Asia indicatee that BSF reesidue allowss red worms to grow threee to five Recen
timess faster than when fed freesh putrescen
nt waste. No
ot only do thee proteins an
nd fats made availaable in the laarvae and red
d worms rivaal in quality tthose of the ffinest fish meeal, but they 3
also represent the most efficient extraction and conservation of nutrients and energy to be found anywhere within the natural world. By allowing BSF larvae and red worms to extract proteins and fats from our waste, we do not have to turn to our oceans and farmlands to obtain these nutrients. When we consider the enormous energy expended in fishing and agriculture, the utilization of these lower life forms becomes an irresistible option to anyone seriously concerned about reducing carbon emissions. But the story does not end here. When red worm castings are made available to a plant as fertilizer, the plant will require far less nitrogen derived from fossil fuels and far less phosphorous extracted from phosphorous‐bearing rocks (an energy intensive process). Most nitrogen fertilizers are derived from natural gas, and world reserves of phosphorous are rapidly dwindling and increasingly contaminated with pollutants such as cadmium. We talk a lot about sustainability, but we will never relate to nature in a sustainable manner until we give back to nature in a closed loop all of the nutrients that she needs to sustain us. Capturing all of the nutrients in our waste and making these nutrients available to the life processes that support us is surely our first and most important obligation as citizens of plant Earth. Likewise, we talk a lot about reducing carbon emissions. But until we learn to utilize lower life forms to recycle putrescent waste, any attempt to achieve significant reductions in carbon emissions will always fall short. 4