Some figures on the biogas?

[Cuicui]

Usine Nouvelle of May 10, 2012]

Why not also methanize green algae?

[Did67]

To "get out of nuclear power", that is defended.

But to prevent pollution by nitrates, so green algae, we must see that it's a dead end!

Methanization "removes" the C from the slurry (or algae), so as not to make CH4, which is burnt. N (nitrogen) remains in the digestate. Who will be spread, according to a spreading plan. As was the slurry. The excess will be found in the waterways, therefore the sea. And trigger the growth of green lagoons, which feed on these green lagoons.

So let's "metahnize" = extract the C in the form of CH4 ... The N remains. AND will be spread as fertilizer ...

And round in circles!

[But energetically speaking, again, it's interesting].

[dedeleco]

In principle, instead of spreading, and returning the N to make algae again, one solution is to dry in the sun in a solar dryer, the digestate full of residual N and C and to burn it, with dry vegetable waste , by heating like this Canadian who, with a better yield, burns all his vegetable waste from the farmer automatically instead of anaerobic digestion, explaining in great detail on 4 videos:
http://www.youtube.com/watch?v=ef0L8ORv ... ure=relmfu

[Napo dwarf]

Methanization "removes" the C from the slurry (or algae), so as not to make CH4, which is burnt. N (nitrogen) remains in the digestate. Who will be spread, according to a spreading plan. As was the slurry. The excess will be found in the waterways, therefore the sea. And trigger the growth of green lagoons, which feed on these green lagoons.

So let's "metahnize" = extract the C in the form of CH4 ... The N remains. AND will be spread as fertilizer ...

And round in circles!

[But energetically speaking, again, it's interesting].

to stop going around in circles, we would have to export to other farms that are not in Brittany and that would unblock the situation over time (of course)
but there you have to count the fuel consumption or you need freight trains to reduce the impact.

[chatelot16]

it is true that spreading the digestate in an area where there is already too much nitrogen is not smart

but there are other regions in France that buy chemical fertilizers! so just put this digestate in a practical form to transport

alas there is a big regulatory problem: it is easy to spread tons of brand new chemical fertilizer ... conversely the digestate is considered as waste and requires spreading plans or I don't know what complication

What if we spread the digestate in the forests? we could make them grow faster, and get even more wood, materials or fuel!

as long as going around in circles, do it as usefully as possible

[chatelot16]

to stop going around in circles, we would have to export to other farms that are not in Brittany and that would unblock the situation over time (of course)
but there you have to count the fuel consumption or you need freight trains to reduce the impact.

anyway where we consume fertilizer it must also be transported ... fertilizer users are not necessarily further from the chemical fertilizer factory than methanizers

[Napo dwarf]

anyway where we consume fertilizer it must also be transported ... fertilizer users are not necessarily further from the chemical fertilizer factory than methanizers

It is not false

[dedeleco]

Burn it after solar drying and balance without increasing the CO2.

In principle, instead of spreading, and returning the N to make algae again, one solution is to dry in the sun in a solar dryer, the digestate full of residual N and C and to burn it, with dry vegetable waste , by heating like this Canadian who, with a better yield, burns all his vegetable waste from the farmer automatically instead of anaerobic digestion, explaining in great detail on 4 videos:
http://www.youtube.com/watch?v=ef0L8ORv ... ure=relmfu

[Did67]

I confirm: the digestate is a "complete" fertilizer (since it contains all the minerals that were originally absorbed by the plant; these minerals do not leave in the gases! It is C which is the basic building block some gas.).

So it is obvious that as such it will have an increasing value (as the prices of fertilizers will soar; in particular the nitrogen, synthesized with great energy reinforcement - this is energy in bar, the N being drawn from the air).

For this reason, in the absence of specific regulations, it is the regulations relating to the spreading of sewage sludge which are applied to the digestate ... In short, the maximum "umbrella" ...

My remark was not meant to "raise a false issue". It was just to say that "contrary" to what I often read, it is not "automatically" the solution to the nitrate problem!

For everything else, no problem: energy recovery, ideally cogeneration (therefore heat recovery, in addition to electricity); valorization of the digestate as a fertilizer quite possible (it is simply necessary to organize it) on a defined area ("spreading plan") ...

For information, we can treat the digestate in "phase separation", with on the one hand a liquid fertilizer (with a relatively low content, which limits the transport distance - the mineral fertilizers are "concentrated"; the digestate or the phase liquid extracted from the digestate are a "solution of mineral elements"; we therefore also transport a lot of water, which limits the range of action!) and on the other hand the dry extract which is composted and constitutes an ammdement organic...

There is no big problem in substituting digestate for mineral fertilizers imported in a given geographical area. This is easily calculated. My thinking was fair to say that if we are not careful, we do nothing to remedy the problem of nitrates and / or green algae ...

[Did67]

Burn it after solar drying and balance without increasing the CO2.

From the "agronomic" point of view, it's silly.

An "intensive" management of natural resources - and energy - (to feed humans, animals, biodiversity, contribute to the energy needs of humans, etc.) presupposes doing it in a slightly more Sioux way. than to burn, burn and burn ...

[take a look at the notion of burn cultivation, and the intensity it allows - recommend reading: http://www.amazon.fr/Histoire-agricultu ... 147&sr=1-1]

As I just explained, the digestate is a liquid fertilizer ...

We also have, in this liquid fertilizer if we spread the sludge, or in the solid phase if we proceed by phase separation, an organic matter which will contribute to the stability of the soils (what we agronomize, we call the soil structure ).

Burning, for me, is Attila!

I invite you, as a big Wikipedia fan that you are, to look a little at the notions of humus, organic matter in soils, structuring (or destructuring by destructuring of humus = mineralization) of soils, 'soil erosion, soil microbial life (in relation to fertility) ... And the organic matter will become gold in bars instead of waste that must be burned (obsession of the old gardeners of bourgeois homes - "it must be clean!")

Not to mention the fact that from the mineral point of view, burning will not be of much use, except to concentrate the minerals.

We can then use the ashes as fertilizer, of course ...

But by having destroyed all the potential "fertility / stability" linked to the organic matter of the soil (which will have been "stupidly" destroyed when I repeat it - it is gold in bars).

I do not want to be too long and barber everyone with my agronomy lesson. It is up to each of you to deepen the reflection of which I have set the framework ...