Home Biogas Systems

Home Biogas Systems seem to be the best option for cooking coupled with the Rocket Mass Heater for warmth. So what is preventing them from being more widely adopted? Is it ignorance, from being more focused on other issues, concern over safety or the 'ick' factor?

Hi Theresa,

I think the ick factor does play into it. I mean, why don't we see a more widescale adoption of home scale composting toilets and use of said compost on ornamental garden beds and perennials?

I believe we have a cultural fecophobia, and I think it's addressed as a topic in many of the humanure books available. Our aversion to our own feces and that of others and of animals does stem from, I believe, some instinct that informed our ancestors of the need to be discrete with human and animal wastes due to their potential to spread disease. While not accurate, the idea that ill health was conveyed or produced by bad smells (bad heumers) is consistent with some rudimentary ideas about sanitation and even composting (if it smells bad, you're doing something wrong).

But I digress. I would love to see a scalable home biogas system, especially one that aesthetically could pass for a regular water-based flush toilet system. I think that emulating the interface we already know, the big porcelain bowl with water in it that you flush when you're finished, is the best way to idiot-proof any system. I am not suggesting anyone's imperfections, simply stating that if you have a system that requires no extra steps or methodology to use properly, you don't have to worry about an uninitiated visitor doing anything wrong to a more complicated system and creating a big, smelly mess.

I only bring this up because it complicates, in some scenarios, the adoption of home biogas systems. Not in that it makes it really difficult or impossible, but that you need to account for it.

Do you know of any Home Biogas Systems on the market or are you looking to design and build one? There is a wealth of materials dating as far back as the 70s from Mother Earth News, talking about methane digesters in India for cooking and heating. A great many of the scaled-down versions I saw were made using commonly available materials, even freely obtained from the local waste stream, in some cases.

Are you looking at this hypothetically, or are you looking to build a home biogas system? How big are you looking? Where are you, and what's available?

-CK

As a matter of fact I supported one on a crowd funding site. If I could have I would have imported them for resale! People seem to be adopters if everything is packaged for them.
https://homebiogas.com/shop/buy-the-homebiogas-system/
As for your comments about our resistance to acknowledging our own body processes, I agree. I am a medical professional and open to new thoughts and processes, and was similarly 'grossed out' when the fecal transfer news item hit the public sensibilities. On further examination, however, there is an academic and scientific reason it would make sense, but we are a long way from widespread acceptance. It's easier to take pills, have procedures or suffer I guess, then dig deeper and understand our own microbiome. Even when a few hospitals realized that hand sanitizer did little good and possibly harmed, we still see it everywhere, although not advertised as heavily.

I use solar power for cooking, either direct solar (concentrators) or PV.  It's cheaper, safer, easier, more reliable, and requires a lot less maintenance.

A single solar panel will produce a lot more energy (on average) than a biogas system processing the waste from two people.  You can easily mount solar panels on your roof and basically forget about them ], whereas a biogas system requires a relatively significant amount of space and requires frequent tinkering/adjustment/maintenance.

True you can add kitchen scraps and increase the biogas output a bit, or you could feed those scraps to chickens or fish and get more food.

If you have done the calculations I applaud you. I live in a hurricane state, with a power company who spends millions to PREVENT solar generation by individuals, while building a multibillion dolaar pipeline for fracked gas- presumably now going for export.

My point is that many people are contributing to the problem out of ignorance and apathy, but may change habits if they are led to a solution. Our water is brought to us through pipes that are old and get more corroded by the massive amounts of chlorine added to water, then flushed together with all waste, including rotted vegetation ground up by garbage disposal units. So we are moving potable water around and contaminating it by the relatively small amounts of waste that SHOULD be 'flushed', but could be contained and broken down organically. Instead, we have single stream recycling, which is either burned or barged far away for processing.

Then again, this 1927 home across the street from me received a demo permit and was bulldozed the next day.https://www.redfin.com/FL/Tampa/4220-W-Culbreath-Ave-33609/home/47273824

I don't know where you are getting your info from, but TECO supports customer solar installations, seems to be a fairly straight forward process:
http://www.tampaelectric.com/company/renewableenergy/customerownedgeneration/

I don't know what your water supply has to do with this discussion.  Besides, the effect of chlorine on corrosion is negligible, the pH of the water has a much more significant effect.  At any rate, if you are concerned about chlorine then don't use city water.  You live in a state where it rains a lot, catch the rain, filter/process it and use that instead.

Since you mentioned the 'ick' factor I assumed you were refering to humanure.  Humanure is a poor input to a methane digester.  Human digestive systems are pretty efficient and effectively remove the majority of the nutrients needed by the digester, so you get very little methane output.  Add to that human pathogens (norovirus, etc.) can take up to 6 MONTHS to be deactivated by a methane digester meaning that you need a fairly large system to hold all the waste.  

The homebiogas system mentioned above isn't even intended (or certified) to be used with human waste, it's designed for kitchen scraps etc.  The best way to handle human waste is to send it to a treatment facility designed to handle it, second best way is a certified on-site treatment facility (septic tank, etc.)

If you want to expend the time and money in a biogas generator, then go for it.  However, I suspect you will quickly discover why they aren't more popular.

Generally speaking, no. You cannot sustainably produce enough bio-gas for a single homestead. I don't have the contacts. But Bob Hamburg. From West Virginia is a leader in biogas technology. Bio gas is trivial at a single family level. But an intentional community could benifit.

I looked into biogas pretty extensively and here is what I found...

With my commercial sheep farm, the fact that I feed them silage, and resulting silage affluent is an excellent biogas fuel; there is potential to build a system and generate electricity. I even have a dual-fueled liquid cooled generator kicking around. That is important because it takes heat to get the affluent to 103 degrees to get the biogas forming...it is a digester after all just like a sheeps stomach, etc.  I even have a bulldozer and backhoe to do the earth work, so I have a lot of what i need to turn sheep poo, household waste, and silage affluent into electricity.

But it still would not produce a lot of KW's.

That is okay, sheep farms are not energy intensive anyway. So even if it kicked out 1 KW per hour, that is 24 KW's per day, of 720 KWs per month, or $100 worth of electrical credits out on the grid.

Now the $1200 question. Is it worth it to spend all kinds of time and money to build a biogas digester for $1200 worth of electricity per year? Generators wear out, systems cost money, and there is always my labor that has value. I agree the cool factor is nice. The green factor is good, but to go through building all this with no real proof it will all work as designed?

It is a huge unknown. I have plenty of other things I can spend money on and get a lot better return on investment. So in the end it is not a that-will-never-be-done-here, sort of thing, it might, but it is low upon the priority list to even try.

Months ago the then  head of Cincinnati Water Works came to speak at my church.
He was there to talk about global warming and the effects it was and would continue to have on our aging sewage system.
After he described the plans for dealing with ever increasing rainfall,he discussed his own idea of building a large scale biodigester to deal with waste that is currently dealt with via incineration.
This makes sense to me. The collection infrastructure is in place,energy is being wasted burning shit, so building a digester that can produce some of power required to run it, plus fertilizer seems like a good idea.
If built large enough,it could also accept local food waste,animal waste,and non-woody yard waste.

Household scale biodigesters are too small, and the inputs are of  poor quality.
Farm scale starts making some sense, if you are already running a factory style livestock operation,with a manure lagoon.
Even then, some financial incentives will probably be needed.

The one thing that might make a small scale digester work for me would be in a "grow house".
Burning biogas for both heat and light in an insulated,unglazed grow space.
That would effectively make biodigesting a way to store heat and light for the winter in the form of manure.
Clearly this might be inefficient,but seems like it could work.

Well I don't know, I have been running a home biogas system for eight years now, it was a ready made system installed by a local company.  As a sewerage system it works just fine.  Ok, even with four people it never produced much more than an hour a day (cooked from it) but it came in handy when it was cloudy. About a year ago the gas pipe developed a leak. Honest truth I kept meaning to get it fixed but the value of the digestate as fertilizer so far outweighed the value of the energy that it was not a priority. I think of it as a six cubic meter liquid fertilizer maker. When I was energetic I would add dynamic accumulators, comfrey and yarrow, etc. Now trees are big I am lazier, just build a nice compost heap next to new trees and water the compost heap which has been inoculated with microorganism tea. When tree is thriving I move to next tree.  Olives love it as well as citrus. Fig not so much.  As soon as I can afford it I will get a bigger one with space to mix green and brown waste. Then we can really get cooking 😁

Hello group,  I want to chime in regarding the smell.  I'm overseas and we have lots of piggeries in the barrio as well as this province.  People mostly dump it into ditches.  It spoils the water table just as soon as it gets to an improperly dug or more improperly maintained (and never capped off) well giving the bacteria a direct path to the water table via the outsides of the pipe dug.  Then there is the smell.  The joke is (I can't really smell it but it is a joke) that once one passes the bridge for the boundary to the barrio they know they have arrived when they can smell the pig feces.  Digested feces is outstanding fertilizer hard to beat.  I've included an article about the problems with the millions of hogs in North Carolina below.  Long ago in the USA it should have become law to digest the feces.  Did you know people still practice taking a giant hose of sorts and spraying down the field with it as raw fertilizer without any concern for the people that have no choice to  live nearby or have family farms nearby?  That is just wrong.  When I have to deal with animal poop smell I put on the equivalent of a clothespin over my nose (literally) when I still had our German Shepherd Puppies in a cage inside at night and cleaning the next morning.  When I got them they both had parvo which I had to get them over which was a miracle in itself and that stuff stank!  When I put the clip on my nose the smell went away until the job was done.  Wearing gloves and keeping it outside where it is well ventilated makes all the difference in the world.  Just my 2 cents on the smell when it comes to animal feces.  Human poop is a different ball game I'm certain but I have a septic so will never try to digest any of that likely.  We are getting ready to build our first based on the Solar Cities IBC open source design and I have to say I'm very excited about it.   Regarding the efficiency of solar panels overtaking the advantages of the methane I completely disagree there as well.  We have all the solar we would ever need in the day and a bit fat zero after dark.  We have a battery bank but methane into a generator is what I would like to get even if I have to mix a small percentage of LPG into it to get a good reliable burn in the genset it would be ideal.  We have an outside kitchen and an inside kitchen.  Maybe I will some day try cooking off it as well but lets see...my current plans are for electric generation after dark.  Links to two articles below...one talking about how the farms are spraying the pig poop on the farms.  Best regards, Mike https://www.theguardian.com/us-news/2017/sep/20/north-carolina-hog-industry-pig-farms   https://indyweek.com/news/archives/updated-study-shows-n.c.-hog-farms-spray-hog-poop-neighbors-homes-cooper-vetoes-hb-467/

Hi,

If a large community (25+ people) have biogas toilets and incinerator toilets, could the biogas fuel the incinerator???

If a large community (25+ people) have biogas toilets and incinerator toilets, could the biogas fuel the incinerator???

This is more complicated question than it looks... and it's been a long time since I read the book about biogas.

Biogas is a mix of gases, primarily methane (CH4) and carbon dioxide (CO2). You will notice, that Carbon (C) is in both of those. Thus, animals that poop out a lot of carbon - like cows - make much more biogas than humans who tend to eat more protein than cows do.

If the Human poop includes a lot of urine, this skews the ratio even more.

Years ago I read some books on the subject and the communities who were doing well with biogas had access to a lot of high carbon material to add to the Human poop in the digester. Since at the time, our farm was primarily chickens (high Nitrogen, low carbon) and the bedding we could access cheaply was wood chips ( lots of carbon, but difficult to digest), I decided not to pursue the concept further. To me, the carbon was better added to our soil than digested into biogas. Many farm soils are too low in carbon, and I'm glad to say that ours has improved considerably over the last 20 years.

Does anyone have experience working with this system?  I am tempted to buy one at some point for our little barn-now-a-guesthouse.  This structure is 60 yards from our house.  
Off grid structure,  rustic. This company offers a family size that includes a flush toilet.  

chad Christopher wrote:Generally speaking, no. You cannot sustainably produce enough bio-gas for a single homestead. I don't have the contacts. But Bob Hamburg. From West Virginia is a leader in biogas technology. Bio gas is trivial at a single family level. But an intentional community could benifit.

My thoughts exactly...doesnt make sense unless you are generating alot of organic waste from humans and farm operations. Also, temperature is an important factor...thats why you see alot of these smaller biogas systems in tropical climates where temperature is warm and consistent year around.

Household wastewater here in the US (unless your Mr Natural) also has other constituents that dont need to go into digesters like cleaners, personal care products, pharmas...And I would think you would still be required by law to dispose of any overflow from the bioreactor to an on-site disposal field.

I still think the easiest onsite wastewater solution here in the US is the septic tank and disposal field or compost bin toilet (and disposal field if you want to be kosher with the gov't). I think more of these systems should incorporate vegetated beds so that nutrients can be extracted from the wastewater before being disposed into the soil.