Week 4: Insects: waste streams and conversion limits
How much of the fish feed a household's own scraps can actually cover.
Search for a closed-loop household diagram and you will find the same arrow every time: kitchen scraps to black soldier fly larvae, larvae to fish, fish to you. This week sizes it. On dry-matter bioconversion and a household's actual plant-based waste stream, the loop supplies a minority of the fish feed and the rest is imported — which is a result worth having rather than a reason to abandon the module. Larvae also have a developmental temperature threshold, so the months the unit runs at all is a site question. Darwin leads, because it is the best site there is for this subsystem, which makes the shortfall elsewhere easier to read. The waste tonnage is a standard per-household figure; what this house throws out, and when, goes on the measurement list.
This week
- Lecture, 15 March 2027
- The scraps-to-larvae-to-fish loop does not closeWeek 4 — threshold temperatures, bioconversion on a dry-matter basis, and the arithmetic that shows the most-drawn diagram in permaculture is mostly imports
- Tutorial, 18 March 2027
- Sizing the insect unit against a scrap streamWeek 4 tutorial — work out how much larval biomass your household's waste can actually make, and draw the import arrow that most diagrams leave out
- Worked example
- DarwinThe Williamss' home leads this week, because its climate makes this subsystem easy. All five homes are compared on the lecture page.
What you leave with
A larval yield derived from your household's waste stream, with the imported share of fish feed stated on the diagram.
You have finished the tutorial when all of this is true, and you can tell without asking anyone:
- your larval yield is derived from the household's 380 kg food waste with every factor stated
- you have applied your site's thermal factor, or declared an indoor rearing load instead
- the imported share of fish feed is a number on your diagram, not an omission
- meat, dairy and fish sludge are routed away from the larvae with the reason given
- your site's constraints allow the unit where you have drawn it
Assignment milestone
Tutorial checkpoint 3 of 10 (2 %) due 5 pm Friday.
Where this sits
You meet the client and work through each candidate system — garden, mushrooms, insects, fish, preservation — far enough to know what it needs and what would have to be measured before anyone spent money on it. Every calculation in these weeks is a scoping estimate on published figures, not a claim about this house.
Expected effort
About 8 hours this week: 2 h lecture and notes, 2 h tutorial, 1 h preparation and quiz, 3 h assignment 1. The assignment hours go into: Waste-stream rows added to the register.
A planning guide from the semester planner, not a requirement and not a measurement of anyone. Tutorial submission sits inside the tutorial hours and the quiz inside preparation; neither is counted twice.