I live in NC by the way and I can't find any mention of anaerobic digesters anywhere in my state's plumbing code or the health department's website. Are there any laws prohibiting the use of home anaerobic digesters? Are there codes and specifications that I must legally follow to avoid being fined?
Is your anaerobic digester that different from a septic tank? What do you plan to put in it? Are you going to get biogas out of it? What happens to the solids after they are digested? Do you plan to apply them to agricultural land?
North Carolina is a pretty lax state, considering all the CAFO pig operations and the abundance of manure they produce. If your digester is small, they have bigger fish to fry keeping the operations with thousands of hogs in line.
Anyway, welcome to Permies! If you give us a few more details of what you plan to do, I'm sure we can help keep you from running afoul of the authorities.
posted 6 years ago
I'm still in the planning stages. I want to know before I start the project what my limitations are and what guide lines I should follow. To start with I'd like to try building a methane digester with an oil drum as the slurry tank and collect the gas in a separate container. In the future I'll be buying a piece of undeveloped property and eventually installing an underground cement and brick tank to collect gas for domestic use. I'm planning to use the anaerobic digester as the only waste collection system for the house instead of a traditional septic tank and the digested solids will become fertilizer for the garden. Would it still be considered a septic tank? Can I build my own septic tank and siphon methane from it and remove the solids or would this be a completely different type of waste system with different rules? As I understand the rules for a septic tank I'll need a permit from the local health inspector and the tank and drain field must meet certain codes. Do I have any wiggly room to deviate from the traditional septic tank system?
posted 6 years ago
If you call it a "house with a septic tank", things are pretty standardized about how it should be treated. It has to be correctly sized for the number of people in the house, the leach field has to be a certain size depending on the results of a percolation test, etc. I can imagine there is fairly little wiggle room.
If you call it a "farm operation with an anaerobic digester" that recovers energy to use for some farm operation, say drying grain or heating a barn, then you probably have a lot of wiggle room. You deal with a different group of people who are less interested in following a prescriptive checklist and more interested that you have the proper engineering to back it up. Instead of the county health department, you probably deal with the state Department of Environment and Natural Resources and they will want to make sure you are not fouling the air or the waters.
I guess it's going to depend on the county you are in and your zoning. The more agricultural it is, the easier you can call it a biodigester. In all my reading, I have never seen rules about what you can't toss into a biodigester. Could be chicken manure, pig manure, spoiled silage, biomass, even what's pumped from household septic tanks.
What you describe almost sounds like the biodigesters that are popular in Vietnam:
I'm not dead! I feel happy! I'd like to go for a walk! I'll even read a tiny ad:
A rocket mass heater heats your home with one tenth the wood of a conventional wood stove