Hello there, I'm considering a scenario for algae cultivation where I divert CO 2 from a Methane Digester into the tank. Haven't decided what to do with the methane yet, might use it to heat the water in the algae tank. I have no gas appliances at this time. The digester's purpose for me is to safely process leavings from my horse stable, mitigating nitrogen runoff into nearby waterways. I also want to head off complaints from the neighbors before the weather turns warm. I've read Reinder's comments on a rooftop membrane for algae cultivation, fed by a raised tank, but I will need to adapt for cold climate (New Hampshire, USA).

I live near a large freshwater lake and I'm thinking that a saltwater culture may be better for me, in case of unintentional runoff. I don't want to contaminate the lake with foreign species. My over all intention with the algae is to raise enough to cover about 6000 l of biodiesel production, enough to heat my house through the winter. Has anyone actually put one of these into production?

Answer: That sounds like a good plan and worth investigating. The Methane Digester, if it is running right will produce about 60% Bio Methane and 40% CO 2, which we can call Bio Gas (rather than Natural Gas? which is a Fossil Fuel). Sounds like the best way for you to exploit this is to operate a combined heat and power system (CHP System?) that would run directly on the Bio Gas.

This will convert your resource into Electricity that you can sell to the grid. You can use the heat from the generator (Distributed Generation?) to provide Hot Water? and backup Space Heating?. You can use some of your electric for local battery charging and local systems operation and sent the remainder to the grid (assuming you are grid connected).

The flue gas from your CHP System? would be composed of air (which is mostly nitrogen + oxygen)and CO 2 as a combustion product, with some other negative products of combustion such as Nitrogen Oxide? (I suggest someone might give a run down on Products Of Combustion) but no Sulfur Dioxide? because unlike Natural Gas?, Bio Gas contains no sulfur.

So, what I am getting at is that the flue gas from such a Bio Gas CHP System? is so clean and loaded with CO 2 that you can feed it directly into the algae culture and into our Sola Garden? growing systems. To summarize, you need a good DIY Bio Digester to produce the Bio Gas and then a CHP System? to convert this resource into useful power, heat and CO 2 as a algae culture and plant growing nutient.

How to grow the algae is another question. - Sola Roof Guy

Any of the links with ? following are pages that we have yet to write but which would probably be quite useful. Any member is invited to open and to make a start on creating such pages - just click on the ?.