TH Culhane shared a link to the SolarCities Facebook group ( https://www.facebook.com/groups/methanogens/?ref=group_header
) . I was unaware of this thread, but have had a lot going on, both personally and with the goat farm I live on, in the intervening time, since your initial post.
I am currently in the process of working out a timeline to construct 3 of the Puxin 10 Cubic Meter ADs with a site manager. Those 3 will be in series for a combination of reasons:
1) Increased total Hydraulic Retention Time (HRT)
2) Increased total quantity of biogas
3) To explore the potential to naturally upgrade Biogas to Renewable Natural Gas standards (pipeline injectable grade).
So, to simplify that, Input 'A' gives Biogas 'B' from #1, about 1/2 'B' from #2, about 1/4 'B' from #3. So, 1.75 x 'B' biogas available, due to triple the HRT from 1 'A' input.
Biogas has roughly 50% of the heat value that pipeline grade Natural Gas has.
1.75 x 2 = 3.50 is the total expected heat value, as RNG, compared to a single unit of feedstock 'A', by only FEEDING 'A', by providing a longer (3x)HRT AND some additional MECHANICAL steps.
The final effluent will have a much lower BOD/COD (Biological/Chemical Oxygen Demand), so, it is more environmentally friendly.
Even if the RNG system fails to fully achieve the expected upgrade, the simple increase in quantity of biogas can be worth the increased system complexity and the RNG upgrading can be readily eliminated.
In addition, my methodology eliminates compressors, by utilizing much simpler pumps for liquid circulation.
Jeffrey L. Frusha
Head of R&D
1411 Gravel Pit Road
Seguin, Texas 78155