Grub composting uses black soldier fly larvae (BSFL) to convert food waste or manure, into compost and grubs. Please read the section on Composting with BSFL for an overview. This resource page is created for documenting research into how to design grub bins for use as mesophilic composters, thermophilic composters/sanitizers, composting toilets, or decontamination composters (for removing toxic elemets).
Research questions and goals are as follows:
- How efficient is a bin design at harvesting the BSFL prepupae?
- How well do bin designs regulate moisture for the type of waste being processed?
- Use inexpensive/common/reused containers or materials to build grub bins.
- Can a bin be designed that will efficiently harvest the BSFL prepupae and allow redworms to further process the compost (and provide another type of animal feed)?
- How to design bins that will allow constant harvesting of the finished compost without starting over.
- How to utilize sunlight to increase composting rate, sanitation, or drying.
- 1 BSFL bin designs
- 2 Harvest efficiency of BSFL bins
- 3 Moisture and drainage
- 4 Myiasis?
- 5 See also
- 6 References
BSFL bin designs
"Grub Composters", "BSFL bins", and "larveros" are all generic terms for noncommercial bins for growing, protecting, and harvesting hermetia illucens, its compost, or the liquid compost "tea".
BSFL bins with trough collector
This can be as simple as a typical compost bin with a trough (gutter) built around it to trap the larvae (but if the entire unit is not covered, rodents or other predators may feed on the larvae before they are harvested).
Commercial BSFL bins with harvest ramps
- The unregistered trademark claims in this section, are questionable.
Dr. Paul Olivier patented many techniques for growing and harvesting black soldier fly larvae. A patent in 2002, describes a cylindrical bin that utilizes elliptical ramps. In 2007 ESR International, LLC, was formed to market and manufacture this device, branding it the BioPod™. It marketed this BioPod™ in the USA, Australia and the EU and subsequently developed the ProtaPod™ and BioPod™ Plus. The newer BioPod™ Plus is manufactured in the USA by Prota Culture, LLC. There is a misconception that cylindrical BioPods™ are no longer available. Circle3 distributes cylindrical BioPods™ world-wide, in two sizes.
Prota Culture now calls the original BioPod™, the BioPod™ Classic, and the new rectangular design, the BioPod™ Plus, however, "official" resellers do not follow this convention, instead calling either one a "BioPod".
Other BSFL bins with elliptical ramps
BSFL bins have been constructed with elliptical ramps using concrete inside a trashcan.
BSFL bins using walls as ramps
Other designs make a ramp by angling one side of the container outward, or, for greater harvest efficiency, two opposing sides are used as ramps to form a trapezoid. (The design in these photos is not secure against rodents.)
Making BSFL bins using tilted containers
A BSFL composter can be made from common containers by tilting them and directing the prepupae to drop into a collection container. The simplest of designs costs about five USD and takes about five minutes to make; a pail hanging at an angle with a hole on the low side of the lid and a deep cup hanging under the hole to catch the migrating prepupae.
Harvest efficiency of BSFL bins
Prota Culture is promoting a new rectangular BSFL bin design called the BioPod Plus. Circle 3 prefers the original BioPod design and paraphrased this quote of Dr Paul Olivier, possibly referring to the BioPod Plus:
"[A square or rectangular unit] is a throw-back to the older designs. In fact it is even more inefficient than anything I had designed back in the '90's. It has, not two, but four corners, which no doubt presents quite a challenge to migrating larva. …So I can only conclude that [some recent adaptations of my Biopod design] have a lot of problems that the original Biopod that I invented years [ago] had clearly solved."
The ProtaPod has relatively small ramps that can easily get obstructed by a piece of vegetable, if not careful. The BioPod Plus has very wide ramps.
Moisture and drainage
Prota Culture contends that the BioPod Plus has a better drainage system and that inexperienced users often get too much liquid due to overfeeding or drain screens clogging. Too much moisture results in death of the grubs, foul odors, and colonization of pest species such as housefly maggots.
(Removed from Wikipedia.) "Although extremely rare, the larvae could potentially cause intestinal myiasis or pseudomyiasis in humans. See this case in Costa Rica There have been a handful of cases worldwide of black soldier fly larvae causing intestinal myiasis and it would most likely be the result of people scavenging food from refuse containers."