On 30 Aug 2016 at 12:32, Christopher Sean Hilton wrote:

> Out of curiosity, do you see a clearly defined place where the
> line is crossed. E.g. does an xS006xx-t vacuum world have vast
> hydroponic gardens, a high tech waste recycling and reclaimation
> facility, or does it have a combination of local nutrition supplies
> that only works if it also imports a significant fraction of it's food
> supply?

Actually, a "low tech" approach to some waste & air recycling would
likely be used.

There's an "artificial wetlands" setup that's popular for sewage
treatment.

Basically you grind stuff up to eliminate lumps and dump it into a
prond with various sorts of plants such as reeds and other marsh
grasses. There may be a sterilization step (using heat or radiation)
first.

Water from the first pond flows thru the plants, which remove a lot
of heavy metals and the like. Bacterial action and other things help
deal with the organic wastes.

You go thru several sets of ponds, with the last one being used to
raise fish (tilipia are a favorite). The watyer from the last pond(s)
is good enough to feed into the intake of the drinking water
treatment plant.

The plants will do a lot of your air recycling for you. And you can
even raise some food crops in the last step or too. Rice, for
example.

Fertilizer can be recovered as well. and the grass/reeds in the first
few stages can be burned and the heavy metals recovered from the ash.

The plants from later stages may work as feed for various animals:
guinea pigs (yes, they are a food animal, still are in Peru),
rabbits, sheep, goats, etc.

Yeah, it takes a fair bit of space and water. On the other hand, it
gives you a *huge* buffer for the air and water.

And you don't need near as much hydroponics and the like. You also
get fish, and maybe even some waterfowl. Ducks or geese?

Heck, the later stages are even usable for recreation if you limit it
to folks who are responsible.

Keep the "high tech" stuff for emergency backup and treating
industrial waste.

Have two independent sets of sewage treatment (and drinking water
treatment) plants. That way you can struggle by on one pplus the high
tech stuff if there's a problem with one set. Or if you need to do
construction to expand them.

Oh yeah, since regardless of whether they use high tech or low tech
recycling, they are going to be limited by available organics and
biomass.

That means that visiting ships will be "encouraged" to dump their
sewage and excess water before leaving.

Yes, *excess* water. If you aren't using a closed system recycling
setup, you'll be turning oxygen + food into CO2 & water (plus
sewage). So you'll end a trip with more water than you started with.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com