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 Beginner's questions: saws, larvae counts, cleaning goo 
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Joined: Mon Aug 11, 2014 9:01 am
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Post Beginner's questions: saws, larvae counts, cleaning goo
Good day everybody!


We're a couple of college students in the Netherlands very excited about BSF and working on getting our own colony running.

We experimented with a couple of different composter designs, and most recently tried to recreate the Bio-Composter offered on blacksoldierflyblog.com (with slight alterations for our purposes). Before, we had trouble with anaerobic digestion at the bottom, so the drainage / aeration system especially was super interesting and good to learn about for us.

The composter has been up and running for a bit, and now we have a few questions and hurdles we're facing we hoped to find some answers / help to from you awesome people!

a) Pure mechanical question: Jerry, how did you get the slots in the drain pipes to look so incredibly nice? :) We’ve tried several different saws and approaches all we get is super crooked, irregular slots.
b) Since BSF aren't native to the Netherlands, we have been buying larvae to start our colony - and have been struggling with estimating how many we need. We have guesstimated that a "healthy" 45 liter composter contains about 5000 grubs - but that is just a (more or less) random guess on our side. Do you know / have an estimate of how many larvae live in a 45 liter composter?
c) How often is a "general cleaning" of the composter necessary (if at all)? We've been adding food waste and flushing and that all is very well, but it seems like there is some material that is just getting old and the larvae won't digest it any more. Should we take all that goo out every couple of months / weeks, not worry about it, or are we doing something wrong and it shouldn't exist at all?

If you could help us out with any of these questions, we’d appreciate that a lot! This is all super exciting. It's rewarding like gardening, just better. ;)


Thanks so much!
TeamLarvae


Mon Aug 11, 2014 10:18 am
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Hello Team Larae, and welcome! We hope to learn more about your project as it progresses. If you're able to share photos of your system that would be excellent.

a) Pure mechanical question: Jerry, how did you get the slots in the drain pipes to look so incredibly nice? :) We’ve tried several different saws and approaches all we get is super crooked, irregular slots.

To make the slots in the drainage pipe I use a miter saw and a blade with many teeth. I've modified my saw so that it stops at a certain depth so that I don't have to worry about cutting too deeply into the pipe. When making the cuts it's important to go slowly so that the plastic doesn't chip or crack.

b) Since BSF aren't native to the Netherlands, we have been buying larvae to start our colony - and have been struggling with estimating how many we need. We have guesstimated that a "healthy" 45 liter composter contains about 5000 grubs - but that is just a (more or less) random guess on our side. Do you know / have an estimate of how many larvae live in a 45 liter composter?

I have a topic where I did some estimates/calculations for that: LINK I'm sorry that I used standard U.S. units of measure, this was basically a fun exercise so I didn't convert to metric when I wrote it.

I believe that 30,000 larvae is a conservative estimate for the capacity of my 23 liter composter (19 liter wet capacity), and that it could possibly be much higer. These numbers seem high if you're focusing on full size larvae, but of course we also have very tiny and medium larvae in our systems.

c) How often is a "general cleaning" of the composter necessary (if at all)? We've been adding food waste and flushing and that all is very well, but it seems like there is some material that is just getting old and the larvae won't digest it any more. Should we take all that goo out every couple of months / weeks, not worry about it, or are we doing something wrong and it shouldn't exist at all?

In my system this fine paste is rinsed out during the regular flooding/flushing operation and therefore does not accumulate. I believe it often becomes anaerobic if left to accumulate and I doubt it provides any benefit to the system. How often it should be removed would depend on many factors so all I can suggest at this point is to experiment with different approaches. Does it smell bad?

I hope that helps some. Please feel free to ask more questions. Hopefully more people will also give opinions. :)

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*I'm not an entomologist, and much of what I write about BSF is an educated guess.


Tue Aug 12, 2014 9:01 am
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Jerry, you're the man, thanks so much for such a quick answer!

We will try and get some good pictures to show.

We have been flushing regularly, but still the "leftovers" accumulate. We'll try and increase our flushing frequency (so far once a week) and see whether that helps. It does smell bad. (Significantly less bad after the flushing, one might add! But still bad.)
We also have been adding new food only every couple of days (about every 5 days), but then in bigger amounts (like 5 - 6kg), instead of a little every day. We'll experiment with whether a more regular feeding schedule (and then smaller amounts) might help decrease the smell - could that be?

Again, thanks so much already! Being not alone with these questions is super encouraging!


Tue Aug 12, 2014 9:28 am
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
You're very welcomed.

A balanced system will not have a bad odor. More frequent flushing may help if you have a very dense colony, but I wouldn't recommend that for a less dense colony.

I think feeding smaller amounts of waste on a daily basis is better. Most of the waste in my composters is eaten within 24 hours or less. The exceptions are hard items like raw potatoes, carrots, etc. Excess waste can be helpful when you're establishing an outdoor colony because the fermenting waste will attract more BSF females, but in an established composter I don't it's beneficial.

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*I'm not an entomologist, and much of what I write about BSF is an educated guess.


Tue Aug 12, 2014 9:39 am
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Hi TeamLarvae, as college students you may be interested to learn that what looks like "goo" is a micro-organism aggregate called bio-film. What you see with your eyes is a micro-environment feature that consists of biological polymers; the goo includes poly-saccharides, poly-peptides & even nucleic acids outside of microbial cells. If you use the search function here for "biofilm" it should lead you to 2 pdf about bio-films.

As for the issue where your bio-film goo doesn't rinse away & Jerry finds his readily is related to how persistent the micro-organisms are in their life cycle. The bio-film has a somewhat layered composition of microbial forms; the sub-species closer to the surface get 1st pick of nutrients & those sub-species farther from the surface rely on what reaches them. However, even the sub-species in the more surface layer will have to use some other nutrients when it has exhausted the supply of 1st pick nutrients.

Bacteria feeding on different carbon molecules have different growth patterns. The bacterial growth pattern where-in the bacterial cell gets their ideally suited nutrition (specific intermediate carbon molecules) is technically called di-auxic growth; & then that cell experiences a type of growth phase. After the first flush of growth & before the cell's next surge of growth that cell must take a time out (lag phase) until the cell re-organizes to be able to use the 2nd tier nutrients properly. This is diauxic growth & although another pattern of growth called non-diauxic can occur it is not the subject of this post.

In simplified terms the persistent tenacity, or relative ease of knocking it off/out, for a particular bio-film is related to the sub-set of micro-organisms & the prevalent intermediate carbon molecules available for the microbial cells to use. There are also what are called nucleoid associated proteins involved in perpetuating the resilience of bio-films & this is part of (not only reason) why those extra-cellular nucleic acids in the bio-film are important.

Which brings up the issue of just what TeamLarvae has been feeding their colony & if it was different enough from what Jerry commonly gives his. As to whether the bio-film is detrimental to the BSF larvae, my surmise is that the bio-film is actually part of a symbiotic relationship which makes some nutrients available to the larvae. Out in the wild food chain any BSF affiliated bio-film would itself attract it's own symbiotic dynamic; it is less persistent as a visible mass due to being acted on in ways/aims that work to impair bio-film stability in order to extract some nutrition from the bio-film.


Tue Aug 12, 2014 3:04 pm
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
That's very interesting gj. For the record, I've been feeding about 60% fruit/veg, 35% grain, and 5% animal protein by weight.

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Thu Aug 14, 2014 2:59 pm
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Hi Jerry (& TeamLarvae), --- I wanted to follow up on your last comment but too distracted until now. There are several inter-related tactics you use which appear throughout the Forum which seem worth tying together. So allow me several blocks of comments as get chance to post then in order to get the ideas out there.

For starters let's revisit what you feed your larvae & the concept that bio-film "goo" (a.k.a. "pudding") is a function of what put into the BSF larval bin. I won't be dealing with protein & so move on to the plant matter.

Plant matter (vegetable & fruit) have hemi-cellulose, lignin & insoluble cellulose. The plant makes "sugar" (carbohydrate) from sunlight & then forms assorted variations of a "carbohydrate" to use. The different carbohydrate "sugars" & the intermediary molecules are appealing to different microbes in the bio-film; meaning the bio-film formation is boosted by what's available.

Hexose sugars are glucose, fructose (found in hemi-cellulose), galactose (active in cell wall) & mannose. Mannose is created when the plant flips glucose's central carbon configuration so those carbons face differently to the rest of the molecular components; it has the same atoms & number of those atoms as glucose. Mannose functions as an energy source when making cell walls (where it is made into galactose), as well as being used to glyco-sylate plant proteins. Mannose hemi-cellulose components are gluco-mannan & galacto-mannan, in seed walls it is a carbohydrate storage form.

Pentose sugars are xylose (in hemi-cellulose as xylo-glucan & when converted by the enzyme xylose into beta-1,4-xylan) and arabinose. Arabinose is the "sugar" which lets plant turgor to build up; in leaf stomata (pores) it is what let's leaf stoma close in response changes . Arabino-galactan is in hemi-cellulose & arabinan is hydrolyzed arabinose.

Uronic acid (uronide) ligno-cellulose "sugars" are galacturonate (a negative charged mono-saccharide found in cell wall pectin) & glucuronate; glucuronate acted on by enzymes is used to make into xylose. There is a chain whereby glucose sugar is acted upon by enzymes to make glucuronate by action of myo-inositol (myo-inositol is itself made from a glucose derivative G-6-P + enzymes). The chain of transformations can even be used to make glucuronate into galacturonate.

Anyway, all the technical aspects aside all those plant "sugars" can be metabolized by one or another of the micro-organisms in the feed substrate. When their intermediary molecules generate pyruvate that in turn can make different micro-organisms put out anything from ethanol (alcohol), lactate (D & L versions), butanol, butyrate, acetate, 2-propanol, more pyruvate & assorted other molecules. In a bio-film one microbes waste is another's energy source.

Look at what gets put into a bin. If it is root vegetables then plenty of mannan (a storage poly-saccharide), if it is leaves then arabinose.

Grasses are about 50% hemi-cellulose & 2-5% xylose. In grain (& ground meal) there are lots of hemi-cellulose "sugars" of mannan, xylan, xylo-glucan & arabino-galactan. There are BSF larvae farmers using spent alcohol brewing grains & one of the reasons this is such an easy medium to work with is the brewing fermentation used up a lot of the types of "sugars" that would otherwise be used by bio-films to breed up it's "goo/pudding".


Wed Aug 20, 2014 3:53 pm
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Hi Jerry & all, --- Moving along: yeast (& fungi) can live aerobically or anaerobically; they are in the air so in a larvae bin. When yeast enzymes act to hydrolyze plant matter there are "sugar" molecules let loose in the immediate vicinity (micro-environment). Out of the lab most micro-organisms live in some sort of association with each other & not as isolated cells; these need not be bio-films & can be simple floculations, spot granules or even miniscule mats in undisturbed substrate.

One can not always be sure that the "sugar" released for the yeast (&/or neighboring bacteria) to feed on was a byproduct of an anaerobic or aerobic pathway. If there's ethanol (alcohol) generated in the chain of events then the micro-organisms were definitely in at least temporary anaerobic conditions.

As mentioned in immediately preceding comment the different plant "sugars" can all be acted upon by microbes to branch out & end up as the compound pyruvate. Once the microbes made pyruvate they actually have the option of using that carbon in pathways that might be anabolic (build up), catabolic (break down) or even simply metabolism that is neither anabolic nor catabolic; in simple terms any changing of tracks in metabolic pathways is made possible by the presence of branch end compounds & microbes make different kinds of those compounds.

In bin substrates where there is water & loose plant "sugar" a bonding occurs between the molecules of hydrogen comprising both the water & the sugar; it's akin to the sticky syrup human chef's mix up. Where the substrate is coated with a "syrup" (ie: a degree of viscous fluid) it keeps oxygen away & that immediate micro-environment is anaerobic.

The existence of minute anaerobic sites means the microbial life there can be fermenting "sugar" & spinning off some alcohol. Because these sites, when still only local pockets, they make a small amount of ethanol (alcohol) that due to the heat of the larvae (& air) this gets vaporous.

When one gets close to a bin with an "off" odor it is the combination of specific molecular volatiles from symbiotic actinomycetes & the head space of the anaerobic "alcohol" that is an olfactory penetrate (like a whiff of brandy). When we only get strong odor after disturbing the substrate layers this is because the pressure from above has closed up the spaces between the components if the bin substrate; the "alcohol's" naturally low evaporation point is stymied & it only can volatilize when we loosen some compaction. Fermentation itself engenders 1 - 3 carbon compounds like aldehydes, ketones & sulphurous fatty acids. Being short chain molecules these are easily volatilized; our human noses registered those odours & most likely so do BSF larvae.

When anything weighing more than the bin substrate is placed upon that surface then larvae can be found aggregating to the underside of the item. I propose this is because the light weight item holds in a localized concentration of short chain organic compounds & the volatile exudation is concentrated under the weight (the head room for expansion of the volatiles is physically restrained from above).

In other words larval reception of the above described event draws them to signals of ongoing microbial metabolism, which for the larvae means readily assimilated food. Jerry uses this characteristic to collect larvae when he puts a colander atop the bin feed substrate & larvae climb up through the holes into the colander - they are "lured" into following some volatile gradient(s) upwards.

For convenience of readers here is a re-posting about actinomycetes (search function can take those interested to more). The distinctive sludge odor comes mostly from certain strains of what are non-patogenic Actinomycetes. In nature this diverse family are a major player in breaking down organic matter, including specialists for manure. Some of their roles is they degrade chitin, dead bacteria/algae & alcohol like molecules.

They produce volative organic compounds & even more of them when temperatures reach 35-40* Celsius, which internal BSF larvae substrate can reach. The odors come mostly from molecules called terpenoids & pyrazine. Of course some strong odor also comes from butyric acid & aldehydes. Furthermore, although not my main candidate for BSF larvae bin smell some aspergillus, myxo-bacteria, amoeba lysobacter & even cyanobacteria can raise a stink.

The actinomycete group Micromonospora, although not a fungi, have filaments (mycellium); this variety gives the odor to muck brought up from a lake bed. Streptomyces are another group adapted to sludge & have variation among strains; they appear shaped like rods or with branched filaments & even as fragmented filamentous forms. Actinomycetes are technically classed a gram positive bacteria.

BSF larvae outer sheathing (chitin exoskeleton) is immediately colonized by Actinomycetes. The actinomycetes produce enzyme inhibitors (& enzymes) that in symbiosis would stymie non-symbiotic micro-organisms from using their enzymes to get at the larvae. Streptomyces produce anti-biotics to control other bacteria/fungi & indirectly help the larvae. There are volatile compounds that inhibit their competitors, like salmonella. This is why BSF larvae can knock down salmonella from chicken waste fed to them & similar pathogenic bacteria in BSF larvae feed - even though the larvae gut builds up the number of salmonella units inside; & conversely why those larvae can pass salmonella on if introduced to a clean substrate.

The odorous volatile compounds are used by the streptomyces for their own group signalling; it is a dynamic called quorum sensing (not discussed here). And the odors are ~50% stronger when the streptomyces host their own symbiont(s), called a phage (viral genes without an actual virus). They produce the sulphurous di- & tri-sulfides, musty mucidon & tetra-methyl norburnanol, earthy geosmin & some meth-oxy-pyrazines.

Moving back to new content in this comment....The bin substrate moisture level is a factor; if it is soupy then oxygen for the microbes becomes complicated. The reason for this is they can only use dissolved oxygen & not air's oxygen which is a gas. If the bin had pure water, instead of dissolved matter, then a maximum of 8mg of dissolved oxygen/ml could be around.

When dissolve oxygen falls to a level of less than 2mg oxygen/liter of substrate the aerobic micro-organisms are at a disadvantage. And to compound the dynamic is that anaerobic pockets in the substrate interfere with dissolved oxygen in the bin; the way that happens is due to those pockets stopping perfusion of neighboring dissolved oxygen on it's way elsewhere nearby in the bin.

Oil & oily feeds are not appropriate to add to the bin because of it's adhesion to particles comprising the substrate. Then the air (gas) oxygen can not dissolve into the water enough & as one looks into the strata down below there's less than a constant 2mg dissolved oxygen/liter which causes aerobic microbes lose out to the anaerobes.

Part of the benefit of Jerry's bulking layer at bottom of the bin is that is modulates the straight downward hydro-static pressure that might not only impede dissolved oxygen getting deep down, but also give space for microbial generated CO2 (whether from anaerobic or aerobic metabolism) to move away from those microbes. If the microbes deep down are surrounded by their own wastes (including CO2) for a protracted time those byproducts can form compounds with unfavorable properties.

Jerry has great success adding new feed only when the old is mostly gone. This is relevant because when spare food overloads the bin there are more micro-organisms replicating & those microbes use up a lot of the oxygen in the substrate, which leads to low dissolved oxygen in the larval living space.

Flushing Jerry's bio-composter to a submerge the top of bin substrate floats the bin contents & disassociates the layers. The rising up shears existing layers & by stretching them creates friction which itself permits oxygen to diffuse for dissolution. This subsequently leads to a rearrangement of boundaries between the matter & promotes renewed inter-action of aerobic micro-organisms with the general substrate (feed).

When the bin is drained oxygen gets sucked in as the water voids out of the floated apart particles. Oxygen then destroys exposed micro-organisms that can exclusively live anaerobically because they, unlike aerobic capable microbes, simply do not have enzymes able to cope with what molecules of oxygen can do to living cells.

Once a bio-film in a bin gets established it's outer population breeds up & in doing so makes more of the poly-saccharide "goo" whose "sugar" hydrogen molecules bind up with water hydrogen to keep a watery skein in place. That water can do 2 different things in context with the surrounding substrate conditions. If there's a reduction of oxygen diffusing into the bio-film the anaerobic microbes put out ethanol (alcohol), but if there's good movement of oxygen through that film of water then other aerobic microbes predominately are multiplying.

Point here is that the bio-film is not a static player in the substrate & if left undisturbed (ex: bin not flushed, just passively draining leachate) the progression is from aerobic predominance to anaerobic metabolizers. Add to the equation how the heat inside the BSF larvae bin trends upward, since this too alters the micro-organism profile. The static hot conditions influences what microbes are actively putting out which particular by-products & the combination of conditions + metabolites affects what the larvae are getting presented to them by their bedding substrate.

Bio-films then aquire chemical gradients & as the aerobic/anaerobic sectors evolve some microbial cells become relatively stuck in place. One feature of those non-mobile cells is that their metabolic rate accelerates & thus whatever metabolites those cells are putting out become more significant metabolites. Of course deep inside a bio-film there may be microbial cells that have shut down or even died; this is relevant because in those cases the metabolites those cells put out can be quite different than what are normally released into their environment.

The fact that in Jerry's periodically flushed bio-composter the later stage BSF larvae seem to prefer the bulking strata would indicate adequate dissolved oxygen down there for microbes; although the late stage larval respiration may itself favor reduced partial oxygen pressure (partial oxygen pressure discussed elsewhere in Forum). An implication is those larvae are dining on aerobic (largely) micro-organisms in the fluid suspension; & more so than when as young stage larvae were in the upper semi-solid level feed substrate. I mention this but have found no literature stating BSF larvae "eat" micro-organisms - every report just says they what they "feed" their larvae.

It may be instructive to explain that one cell micro-organisms are not static entities; they have a phase called lag (where they are getting organized producing proteins to use & making useful enzymes for itself), followed by a phase called log (where their growth is logorithmic or onward) & lastly a stationary phase (cell just being itself, no longer growing). Depending on which cells are in what phase & where in the substrate there are distinct things occurring inside the larval bin.

The tendency of fixating on a phase overlooks the fact that even in a lag state under those cells can still be doing some reproducing. I propose that another of the reasons late instar larvae favor hanging out in the bulking strata of Jerry's bio-composter is because there the conditions for lag phase microbes is less compromised & their metabolism in that stage spins off molecular compounds the late instar larvae prefer as they develop toward actual pre-pupae (non-feeding, but not necessarily non-absorbing larvae).

The late instar larvae have less preference for the strata above because there are lots of microbial aggregates (not necessarily incidentally only as bio-films) that have been immobilized in the bulk substrate. The low dissolved oxygen (or anaerobic spots) or even having it's predominant "sugar" sustenance used up will incline certain microbes to enter their stationary phase.

When there are lots of a microbes going into their stationary stage they actually alter the way their metabolism had been organized. The must & do re-orientate in ways that causes those microbes to put out different metabolites as by-products of their changing ways. Flushing the bio-composter would wash out those secondary metabolites & even microbes that died following their stationary phase.

Looking at flushing in terms of microbial function it is not a steady state paradigm; Jerry refrains from flushing new bins & cut back on frequency does it to established bins. In new bins you don't want to wash out the "baby" log phase microbes & later on although it clears out "problem" stationary phase microbes doing a flush too frequently never gives the log/lag phase microbes enough time to adequately replenish themselves.
END (unedited)


Wed Aug 20, 2014 7:16 pm
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Thank you very much gringojay. As usual, I struggle with highly technical information, but I feel it's worth the effort.

I'm curious about the effect of the translucent box I use in terms of allowing UV rays into the substrate. Assuming significant quantities of UV enter the waste; does this favor aerobic bacteria or have some other benefit other than allowing better observation of the waste?

Quote:
BSF larvae outer sheathing (chitin exoskeleton) is immediately colonized by Actinomycetes. The actinomycetes produce enzyme inhibitors (& enzymes) that in symbiosis would stymie non-symbiotic micro-organisms from using their enzymes to get at the larvae. Streptomyces produce anti-biotics to control other bacteria/fungi & indirectly help the larvae. There are volatile compounds that inhibit their competitors, like salmonella. This is why BSF larvae can knock down salmonella from chicken waste fed to them & similar pathogenic bacteria in BSF larvae feed - even though the larvae gut builds up the number of salmonella units inside; & conversely why those larvae can pass salmonella on if introduced to a clean substrate.

Is this what I've heard referred to as "BSFL 'excreting' an antibiotic" when they enter their last instar?

Quote:
Oil & oily feeds are not appropriate to add to the bin because of it's adhesion to particles comprising the substrate. Then the air (gas) oxygen can not dissolve into the water enough & as one looks into the strata down below there's less than a constant 2mg dissolved oxygen/liter which causes aerobic microbes lose out to the anaerobes.

My use of Dawn Ultra dishwashing liquid did not seem to cause any problems that I can see. The colony in that composter has thrived after the treatment. Could this be a reliable solution to the accidental addition of excess fats, and could it even be a factor in allowing intentional processing of fats in the system? Here is a list of ingredients provided by Environment Working Group's page for Dawn Ultra

Quote:
Point here is that the bio-film is not a static player in the substrate & if left undisturbed (ex: bin not flushed, just passively draining leachate) the progression is from aerobic predominance to anaerobic metabolizers. Add to the equation how the heat inside the BSF larvae bin trends upward, since this too alters the micro-organism profile. The static hot conditions influences what microbes are actively putting out which particular by-products & the combination of conditions + metabolites affects what the larvae are getting presented to them by their bedding substrate.

In your opinion is there an optimal temperature range? I ask because I've been using the drainage system in a way that I think might lower the temperature in the waste. By leaving the drain valve open I imagine that there is a draft effect like that of a chimney where cooler air is drawn up the drain tube as hotter air from inside the vertical drain pipe rises. I'll post soon to share the set up where I can leave the drain open without losing the leachate or larvae.

Quote:
Looking at flushing in terms of microbial function it is not a steady state paradigm; Jerry refrains from flushing new bins & cut back on frequency does it to established bins. In new bins you don't want to wash out the "baby" log phase microbes & later on although it clears out "problem" stationary phase microbes doing a flush too frequently never gives the log/lag phase microbes enough time to adequately replenish themselves.

People often ask me how often to flush their bio-composters. The truth is that I go by a gut feeling. That's not the best answer I'm sure, but most things I've developed for BSF composting have come from intuition (right or wrong) and not any understanding of biology/chemistry. :)

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*I'm not an entomologist, and much of what I write about BSF is an educated guess.


Sun Aug 31, 2014 4:38 pm
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Hi Jerry, - I have been taught that UV light does not enter through plastic. So, in your translucent bio-composter there is no UV damage being done to either aerobic or anaerobic bacteria. For general information purposes UV light striking bacteria on a flat surface can damage their DNA leading to death, but on irregular surfaces the downstream "kill" rate is probably ~75% at best.

There are actually proteo-bacteria that do thrive using light (they are photo-tropic bacteria). Different varieties use different nano-meter (nm) wave lengths of the light spectrum to make energy (ATP) because they have light harvesting genes that allow them to make light harvesting peptides (an assembly of amino acids).

These include what are called aerobic an-oxygenic (low oxygen) bacteria & some are found in fresh water/slurries; the anaerobic versions of photo-tropic bacteria are not discussed here, nor are those salt water ones. A few of the fresh water ones are green since they make bacterio-chlorophyll & these (as well as purple varieties) are found in sewage collections; they are capable of adaptable to using sulphur, which is found in fecal sewage.

I mention these because in the translucent bio-composter if one sees green growth down in the lower reaches of the bulking layer the immediate assumption is that it is algae. Some may (?) be strains of aerobic an-oxygenic bacteria; especially since these type of bacteria, although being classified as aerobic, are influenced by the oxygen partial pressure in how well they generate energy. If the oxygen "pushing" down on them is low they can start to move into their "log" phase of logarithmic growth/action better; in sewage the compactness holds off the oxygen from them (so to speak) & they activate.

Elsewhere in the Forum I proposed that the late instar larvae are seen through the walls of the bio-composter to be "preferring" the lower strata of bulking material because down there the oxygen partial pressure is less than in the upper strata. My surmise was the larvae seen in the bottom strata are consuming diluted slurry & of course this is what aerobic an-oxygenic bacteria dine on. I assume there's also a reasonable amount of sulphur reaching them, since the upper layer microbes may incorporate some sulphur into their cell but they are not genetically endowed to be able to use sulphur to drive their method of energy production.

A good technical introduction is (2004) "Seeing green bacteria in a new light:genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria"; free full pdf =
http://www.rcn.montana.edu/Publications ... robiol.pdf


Mon Sep 01, 2014 3:03 am
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Again Jerry, - There are fungii that metabolize fat; these belong to a genus called Malassezia. Because these fungii can not make their own lipids ("fat", fatty acids) they put out enzymes ("-ase" in word means enzymatic) that cleave "fat" on other life forms ( these enzymes include lip-ases, phospho-lip-ases & acid sphingo-myelin-ases).

There are strains which are known to cause problems like dandruff, atopic dermatitis, pityriasis versicolor, psoriasis, etc. for humans; exists on our skin & can even the colonize ear. Human associated strains of Malassezia are living as a "yeast" when it is not causing problems for us; but when the fungus shifts into a phase where it is actively producing mycelium to feed then we suffer.

However varieties of Malassezia are also associated with life forms like plant roots even things like the exo-skeleton of soil nematodes. I wouldn't be surprised if some varieties are living in BSF larvae bins, or even on their very surface. The thing is this fungus is unlikely to be able to "consume" a huge amount of fat fed into a larvae bin; but it is probably in there even if just what falls in from the skin of the human caretaker.

As for simple dishwashing detergent, like Dawn. The general concept is it is a surface tension breaker; so, it will help loosen "fat"
to make that more soluble.

In micro-propagation of plants it is used to make a mild washing solution for a tiny plant cutting as part of a pre-treatment before using a piece in sterile culture. It helps get the microbes/spores loose in the nooks & crannies of the piece (a more precise laboratory wash is 1-2 drops of dish detergent with 1 ml of the non-ionic surfactant "Tween 20" per liter H2O).

Using dish washing detergent in conjunction with flushing doesn't "kill" the bin micro-organisms, or apparently harm the larvae. It will dislodge some micro-organisms that then flow out with the draining water - but the remaining ones will re-inoculate the bin & replicate anew.

But a curious thing about micro-organisms is that when you inoculate a culture with a lot of the microbe they grow "sensing" a competition for resources & gallop through their lag phase (stage when assembling vital proteins/enzymes) to get going. These enter their log phase (logarithmic growth) a bit quickly & although can replicate they also "burn out" fast. In contrast when inoculate a culture with minimal amount of a microbe they develop slowly (lag phase lags along) but although later as replicators (log phase) more productive in the long term.

The relevance I see to flushing the bio-composter is two-fold; we can assume any micro-organisms that are not showing detrimental effects on the larvae are symbiotic with those larvae. When using simply water for flushing it reduces the microbes so the remnants rebuild their colony with renewed vigor & by extension this means better performance of their symbiosis with the larvae. Discussed elsewhere in the Forum (previously in this thread) is how the problems with bacteria comes about when there are too many in their later life cycle stationary phase & are starting to shift over the types of metabolites they spin off that the larvae then encounter in their environment.

Incidents of flushing with dish washing detergent would be (is) a non-toxic clear out of some proportion of the microbes, but more so than just water would be; which in itself is not problematic. I don't think it would be preferable to always use detergent because it conceivably would set back the micro-organisms to where they are not performing their symbiotic function - they might "lag" behind a bit too often instead of doing their "job" for the larvae.

Again, intuitively not flushing much when the bin ecology is in it's relatively early stage & thus could be still evolving niches for all microbes makes sense. Let the microbial symbionts get a little "work" in before flush out the "retirees" (ex: stationary phase bacteria) & then "freshen" up that colony. You want some "veterans" (ex: log phase bacteria) playing on that symbiotic colony's team until the "new" players (ex: lag phase bacteria) get into the swing of things. Then those later periodic flushes of the bin micro-organisms can't disrupt symbiosis with the larvae because a colony's population will have lots of all life cycle phases going on among it's own kind.


Mon Sep 01, 2014 4:41 am
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Post Re: Beginner's questions: saws, larvae counts, cleaning goo
Lastly, - I certainly do think the Bacillus subtilis larval gut bacteria strains could be the source of anti-biotic purged from their gut. Quote: "... B. subtilis ... produce more than two dozen antibiotics ... (also) involved in biofilm ... quorum-sensing ... programmed cell death ...." As per (2005) "Bacillus subtilis antibiotics: structures, syntheses and specific functions"; link = http://www.ncbi.nlm.nih.gov/pubmed/15853875

For input on the ideal temperature range I do not feel qualified to say. The dynamics of changing larval life cycle sizes probably indicates one set of circumstances does not remain the ideal for BSF larvae/pre-pupae.

Looking for any patterns in the bio-composter design of breeding bin I return to the enigma of why so many late larvae are seen down in the bulking strata. If the lower drain is left open to draw in air & there is a mid bin layer of bio-film atop the bulking strata then maybe there is going to be less than a linear movement of air doing a chimney up-sweep.

I suggest taking the temperature down in the bulking strata in a bio-composter having lots of larvae nestling down there. Since opening the drain would theoretically draw in cooler air the warm air in the bulking layer should rise. The question is whether that warmth is delayed upward by the bio-film (&/or feed substrate) in the bin & what might that do.

Let's assume the bio-film is a natural symbiotic partner in a BSF larvae colony; meaning even larvae in the wild are living in symbiosis with a bio-film of some scale. If (although without translucent sides we can't see them) wild living late stage larvae in their colony also prefer the lower depths of their food environment then I extrapolate that to mean late stage larvae actually prefer some trapped heat warmth.

Young larvae, in contrast, seem more interested in getting into the feed stock & doing some "snap, crackle & pop" consuming. Which places them nearer the surface where it is easier to transfer away some heat, even if from evaporating moisture carrying heat.

Those assumptions leads me to propose at least 2 situations where the bio-composter design could be utilized to modulate heat. Early in the bins larval colonization there are less pockets of bio-film & by opening the bottom drain the updraft would able to cool the upper feeding substrate level where the young larvae like it (supposedly) cooler.

As the bin builds up more bio-film pockets then any updraft will have to move more slowly upward. Incidentally, although the word "film" evokes an image of a single sheet like layer stretched out that image is misleading. To get a better picture of how bio-films, plural, can thrive think of the human teeth - a totally different bio-film can be found on different facets of the exact same tooth.

O.K., so opening the drain "cools" the young larvae, but once there's a pudding of bio-film goo one of it's side effect "warms" the late stage larvae & allows less "cooling" up drafts going above. Now, if the bio-composter has been consistently flushed so that there are only pockets of bio-film & minimal pudding then the updraft could still cool the top strata - except it then probably won't warm the late stage larvae sipping their nutrition down in the bulking layer. And with that in mind Jerry's concept is to mimic wild larvae living conditions where rain periodically soaks the colony.

Which is why it would be instructive to measure the temperature in the bulking layer when the late stage larvae start to swarm down there in the bio-composter. In theory, but theory must yield to data, those bottom dwelling larvae are living in a higher temperature than the surface young. The seeping down fluids from the rotting food above is probably all they need to prevent a linear build up of temperature simply going up & up all day long.

If the late stage larvae are down there & it is warm then any bio-film trapping of heat caused from the open drain should be "nice" for those older larvae. Of course again theory is not data & temperature measurements might show that heat does not get trapped below even a pudding mass of bio-film.

And, if not too obtuse a point, allow me to point out that many say the colony heat goes up because of the friction from so many larvae moving through the substrate busily feeding. Quite possibly this may be too simplistic.

The metabolic activity of the larval organism actually generates heat & I think this is more relevant than friction. Not only that, the larger they get the more heat each one's metabolism engenders. Another way of looking at this dynamic is the larger the larvae grow the hotter they can take their living conditions & the warmer they are (up to a point, obviously) the better their metabolic functions perform. I'd predict that opening the drain & having bio-film hold in some heat for the older larvae may actually be more desirable because they'll get even more robust (metabolism enhanced) for when change into pre-pupae & later pupae.

The idea of opening the drain for air circulation sounds like a win-win strategy. The young larvae get cooled & the late stage larvae get some extra daily transitory warmth.


Mon Sep 01, 2014 6:26 am
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