As an addendum, I also think that it puts you two years behind any bioremediation that could be started on breaking down or sequestering whatever nasty toxic gick that passes into our systems, be they the cause of pesticides and insecticides, preservatives, medications for us or our meat, whatever, if, for some reason, a contained, anaerobic pyrolysis is a bad idea, which would get it done in bucket batches as they appear and do it in one burn, leaving us with biochar.
I think what is necessary whatever system we're discussing is a way to test everything for pathogens and the toxic gick stuff: The poop in a finished bucket; the ground around the mobile structure; the ground around stationary dry and wet outhouses; the poop after a couple of years in a sealed bucket; buckets after being processed for biogas; the ultimate
compost product of a multiple detrivore system starting with BDSF; the produce, including all parts of all plants grown out of the fertilizer, everything. Just because we can't identify every possible thing doesn't mean we can't take the most recognizable examples we know we want to eliminate from the nutrient cycle and use them as markers to gauge relative toxicity and its progress, to test our hypotheses about what we think is going on, to ensure we get to where we want to be.
You could still have systems that are added to in batches that cycle those batches for two years before they come back into contact with the food system, but I think a properly designed closed-vessel biological approach would cycle in months, and a poop kiln would do it in hours or less. leaving the remainder of the two-year exile from human touch to be used in plant growth for repeated chop and drop paddocks where animal access could be controlled.
Also, the only good things about plastic buckets and barrels are the cost, durability (except in sunlight and when you're actually using them), and their sealability, which is moot if they fracture in freeze/thaw cycles or with accidental impacts.
Sump transfer hardware, hoses, threaded ports, and valves, all properly durable metal, can eliminate human contact and accidental bucket fracture and subsequent catastrophic full bucket failure fallout (messy poo all over you).
Lastly, although, I'm obviously suggesting a pyrolysis kickstart followed by isolated systems that optimise conditions for nature to do it's work for us, I was also thinking that if a bucket were used for holding it, wouldn't a metal that is a natural anti-microbial be useful? Brass was popular for a long time for hand grips and doorknobs for just this reason.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein