[Ludi]

Sorry, you lost me pstarr with your comments about the greenhouse. Which greenhouse? The one on Martha's Vineyard? I was talking about the waste processing systems, not the greenhouse.

[MonteQuest]

$this->bbcode_second_pass_quote('Ludi', 'M')onte, I'm not the one claiming they are inconvenient to use, someone else posted that, months ago, I don't remember which thread.

I know they collected the dung before, to use as fuel.

*sigh*

[Ludi]

Because I remembered that objection from the other person's post and wanted to bring it up to see what the answer might be to the question "do you know how many are being used?" The answer seems to be "they are building more" but that isn't a clear answer to my question. I'm starting to give up trying to get clear answers to what I think are clear questions.

Trying to get information is often just too hard.

[Ludi]

$this->bbcode_second_pass_quote('pstarr', 'I') assume all waste material is recycled into nutrients via greywater and blackwater systems. (At this point I do prefer Humanure--lower tech and just as safe.)

[MonteQuest]

$this->bbcode_second_pass_quote('Ludi', 'B')ecause I remembered that objection from the other person's post and wanted to bring it up to see what the answer might be to the question "do you know how many are being used?" The answer seems to be "they are building more" but that isn't a clear answer to my question. I'm starting to give up trying to get clear answers to what I think are clear questions.

Trying to get information is often just too hard.

[Ludi]

$this->bbcode_second_pass_quote('MonteQuest', '
')
Ludi, I was clear. I said, "no." I don't know how many are still being used. Sorry.

Google biogas India

[Ludi]

$this->bbcode_second_pass_quote('pstarr', 'S')olviva is a super-insulated solar-lit and solar-heated greenhouse that I assume uses compost for heat and nutrients. That is the principle that might prompt the construction of such an elaborate structure.

The structure is made from wood ("natural") and glass (?) rather than long-lasting concrete, steel, and alumimum. It's constant maintanence (especially on wood-denuded Martha's Vineyard) detracts from its longevity and sustainability. The Ark at New Alchemy was designed to last hundreds of years.

I do not believe the Solviva system is integrated into the immediate ecosystem (the land and organisms around the structure). It would only be sustainable (by permaculture measures) if it relies on regional nutrients including local human wastes, recycled and returned compost, and some on-site fertilziers (green manure, animal poop)

Solviva is an important demonstration device to remind Martha's Vineyard ecotourists (such as myself) of possible alternative living systems (and "living systems (tm)")

[gigacannon]

Humans mainly eat simple sugars, so there's not much carbon left in human dung. Cows, on the other hand, eat grass, which is mainly composed of cellulose. Cellulose is broken down by bacteria in the cows' stomachs, and it's this that leads to so much of the methane produced.

This isn't as good an answer as I'd like. I'd better go research it.

[Caoimhan]

Isn't this a biofuel thread? Waste is biomass.

[grabby]

I think more appropriately we could say

Biomass = waste.

More accurate.

[nethawk]

Waste-to-Energy of course cannot completely meet the world's demands for energy, but that doesn't mean that it shouldn't be used. WTE for sewage make perfect sense, especially on large treatment plants. The Hyperion Treatment Plant which serves Los Angeles generates over half of its internal needs via the digestors, offsetting millions of dollars worth of electricity bills per year, and saving the natural gas that would been used to make that electricity.

The treatment plant in my town processes about 3 million gallons per day, but they currently flare the methane during summer and use it for heating during the winter. With all of the housing units that are being added and former septic-tank areas that are being connected to the treatment plant, methane production may make a generator feasable. Electricity prices are unlikely to influence it, as the local utility (PPL) uses local coal for 60% of its energy, nuclear for 30%, and hydro for most of the remainer. Very little oil and gas (which is good).

Digestor gas should AT LEAST be used for heating when it is needed, and it would be nice to see digestors installed at the large commercial (factory) farms which currently pump manure into lagoons and waste its energy value and usually fertilizer value as well. They could burn the methane in IC engines, generate electricity for on-farm needs, sell the remainder to the grid, and use the waste heat from the engines to heat the animal barns during winter.

It makes no sense to throw that energy away.