Biodigester Design/construction - part one

[@brightmal]

Okay, the point that jumps out to me here is that the liquid level on the Solar cities design should actually be a few inches lower than the top of the IBC. The key here is closing the gas tap every time you add new substrate. The gas pressure inside stops the liquid level from rising, and the only way for the overflow to go is the digestate outlet pipe. I've built one with this design, and it works, at least in the summer.

[@ItsAlwaystheQuietones124]

Thank you for the mention and showing the filters. Def like the set up on them. I also have been considering the side hole on the digester as well. More service area for gas just makes sense.

[@jakehvazdamusic]

I use two, 55 gallon barrels. A bulkhead fitting with a spigot near the bottom to release the liquid fertilizer. About 40 inch long, 6 in wide pvc from the bottom out the top with cap for inflow of organic material. Then simple fittings and hoses from the slurry tank, to filters, to final 55 gallon barrel with pressure release valve. Where the gas will stay until its bottled into a propane tank by use of air compressor! Still in process of constructing it but will upload when done

[@mmnyako]

Thank you for sharing! why did you remove your steel wool filter? Did the activated charcoal help filter the CO2?

[@BiogasUSA]

Hello. I moved all the filters to be between the digester and the inner tubes. That way the gas passes through them slower and they have a better chance to work. I have left the charcoal filter but replaced the steel wool filter with a molecular sieve. I will be making a video about my current filter set up shortly.

[@mmnyako]

Thank you for sharing! Did you remove your steel wool filter? Did the activated charcoal help filter the CO2?

[@BiogasUSA]

I am not convinced the charcoal filter had any effect. I did remove the steel wool filter, I know for sure that was not effective enough. What I found was a water bubler was highly effective against h2s. If I remember correctly when I was using steel wool I had 60ppm in the barrel and 40ppm in the inner tube. Currently, my digester is more mature. I have 200ppm in the barrel and with just a water bubler I can maintain 0ppm in the inner tube.

[@mrithyunjaibalakanagaram9636]

is cow manure the only type of manure that can be used?

[@BiogasUSA]

Hello! No, cows are not the only animal. You can use the manure of any animal with a special stomach called a rumen. A few other options are sheep, goats, deer, giraffe.

[@mrithyunjaibalakanagaram9636]

Thank you!

[@russelloconnell7504]

Where is a good source of cow maunure? Dairy farm of course. But how about us who dont know dairy people. Would the bags of steer manure from home depot work? Or are they too inactive?

[@BiogasUSA]

You want it to be fresh out of the cow.

[@lugo2214]

Hi Have you constructed a digester with your updated design? Di it out perform the previous?

[@e-clipslandscaping4367]

Why do you think you need more service area, my understanding is the microbial life is what’s making the gas not service area ?

[@BiogasUSA]

Hello. There are two reasons First, I could certainly be wrong, but I feel a larger liquid/air interface will let the liquid release the gas easier. Also, if slurry is obstructing the gas outlet then it will be pushed down your tubing and wind up in your filters/gas vessels

[@BiogasUSA]

Do you think that soda would go flat faster if it has a larger surface/air interface?

[@the_natrix9959]

Mr. empirical here...lol. install a quality flow meter after the desiccant notifier. Measure the gas volume output. Compare. Anecdotal speculation is often costly.