The Methane Midden was my first attempt to recreate, on a significantly smaller scale, Jean Pain’s Epic Compost piles that he used to heat everything from his house, to greenhouses, to sheds, and he even buried methane digesters in them. He worked on these projects for over a decade and did some truly Epic Shit. The dude was a bad ass and a Bioneer extraordinaire – and he did all of it 40 years ago. My Methane Midden didn’t produce any capture-able methane. Why? I screwed up the PH, screwed up the solids:liquid ratio, and was doing 4 other projects at the time and didn’t focus on it as I should so missed both of the above, or at least failed to address them. But that is ok, because when you screw up, you reap a boat load of learnings. So it was with me.
- Spend more than 30 minutes planning a project. A full third of the issues below were foreseeable and I could have caught them. But that material was decomposing with every minute I delayed, and/or some other guy could have grabbed it. I struck when the iron was hot.
- Rubber is a crappy heat exchanger. Duh.
- Looping hose through a pile haphazardly doesn’t work real well as an efficient heat exchanger.
- Digging out said looped hose sucks. Jean Pain figured this out early on, and switched to an elegant solution. So will I…
- 540′ (164 m )of garden hose only holds like 40 gallons of water (151 l) , which at 6 glns/min (15 l /min) only keeps the water in the pile for like 7 min. In rubberized tubing. Yeah, THAT is going to heat up…
- Rectangles are stupid. The bio-chemical reaction that happens in composting works as a sphere. Rectangular piles waste 20%+ of the composting material as it never hits prime temp. ALL of Jean’s piles were cylindrical (ish). Rectangles… easy to build, crappy in use.
- Putting large tanks in the middle of the pile screws up the reaction. Again, the reaction in a compost pile needs about 3′ (1 m) of width (in all directions) to achieve critical mass. The 2 digesters in the middle of the Methane Midden meant I only had 2′ (60 cm) of compost materials on each side of the digesters. I thought the straw bales would provide enough insulation to overcome this. I was wrong. Jean Pain’s piles were HUGE and over came his buried tanks with shear volume – he had 9′ (3m) of material on each side of the tank – more than enough apparently.
- Hot Water or Methane. Choose One… At the size I was building, I would either keep the methane digesters at 100 degrees (38 C) or heat the water to 120. I couldn’t do both without separate heat exchanging systems. Jean Pain had 400 meters of 2″ hose (1200′) so his first 100m (300′) went around the digesters to cool them, and then he had 300m (900′) of exchanger left to heat up. I can get an exchanger that big in my piles, but not with a digester in the middle. Hence the L’eau Chaude pile…
- Pine Needles don’t really work. The Methane Midden came into being because some local guy limbed up a huge amount of pine trees – there was no other time I had seen so much “green” brush all at once. Pine needles have nitrogen, so the pile heated up, but they also have alot of resin in them which ultimately blocks decomposition. This meant the pile died after 2 months, where I suspect a deciduous based feedstock would have gone for twice that long. The compost didn’t really finish, ending up as a humusy mulch, for this reason. I worked with what I had and learned a ton – like I need to source my own material, and also what happens when you pile up 10,000 #’s (4500 kg) of chipped white pine limbs (140 degrees for 2 months, then 100 degrees for another 1, then ambient)
- Jean Pain style Brush Composting Works. While dismantling the Methane Midden this week I didn’t come across any anaerobic sections, and the pile was still damp. After 5 months. Soaking the material for 2+ days adds enough water to sustain the reaction, and the large particle size of the brush provides enough bridging to let air in. On paper / first glance composting this way is insane. But IT WORKS. I still need to figure out the proper C:N ratio – higher on the Carbon side than a traditional hot compost pile to sustain it, but more Nitrogen than the Methane Midden had to keep it going longer. I ran several smaller experiments over the summer and they tell me that .5-1″ (1-2 cm) trunks of brush with full leaf should be ideal: thicker trunks, say 2″, and the pile die quickly, to thin or brushy (mature lambsquarter) and the pile goes into runaway mode – hitting 178 F (81 C).
- Green wood is important. It is precharged with moisture, and the sap is sugary. Bacteria like sugar… Mixing a pile with dry, dead chips and leaves and you would need far more water –if you can even get enough into the chips- and alot more leaves, leading to matting. Luckily the vigorous willow strains such as salix dasyclados will put up .75-.875″ rods in one year of coppice growth. Just sayin.
- 8 Cu yards of nearly done compost will turn you into a glutton Will explain tomorrow, suffice it to say virtually EVERYTHING in my yard got a 1-2″ (2-5 cm) layer of humus rich mulch!
So, the new Midden is underway. It will be hot water only, and it will be cylindrical. It will be made with primarily made from deciduous plants. There will be no tanks, and I am upping the tubing to 1″ ID. There will hopefully be as much as 900′ (300 m) of it if I can find some more compost material. That should increase the volume of water in the pile by a factor of 10. Also may purchase a new pump that will drop flow rates to under 2gpm, potentially keeping the water in pile for over 2 hours rather than 8 minutes.
Work is happening faster than I can type up posts, though expect a flurry in the coming weeks. If you want to keep more up to date, I will be updating Facebook more frequently with mini reports. This is going to be awesome!
Be the Change!
More to come soon as I do a proper write up, but here are some links I thew on Faccebook from today’s Coppice Harvest which netted just shy of 15 cubic yards – about 6000#’s. Holy crap was this a fun day. Broke the hitch mount off the dump truck and I barely even care. The Vermeer 600XL chipper is bad ass. Its also more tool than this project needs, but figuring that out was one of the reasons I rented it. Thanks again to Chris and Mark from work for helping me out!
And thanks to coppicing, no trees were killed in the making of these videos!
Right. So the past 2 weeks I was out of country – 6 nights in Victoria, Australia in the Great Otway National Park and then 7 nights in New Zealand 3 nights in Kiakoura on the South Ocean and another 4 getting to know Wellington. It blew my mind and I am in no condition to post about it yet – still fermenting. But time waits for no man, and with the leaves falling it is almost past time for me to get my arse in gear and build the second midden. So here goes.
First off, this midden will have several differences. The first, of course, is in intended use. This Midden will be designed to produce hot water (l’eau chaude) v. the Methane Midden’s failed attempt to make methane (botched the PH and ran out of time). Second, this the Midden L‘eau Chaude will be constructed with freshly harvested brush. That means a few things. Like I needed to find 8000#’s of brush and that is a bit more than my backyard can supply. Oh, and I need some new tools like chainsaws. And finally I need a Big Az chipper. How does a trailer mounted 27hp Vermeer sound? It sounds kick ass to me as long as no one goes Fargo… Renting the chipper for now, but if this works, I can see a huge shredder in my future. Someone has to figure out how to run these on ethanol and methane, right? Perhaps… that shredder runs $8k.
We’ll get into the technical pieces of the l’eau chaude in future posts, but for now, lets talk through sourcing the brush. I called some of my friends that own land and was able to secure enough material in no time. It isn’t hard to wonder why. Say you own 20 acres, 10 is in woods. You get a call from a friend who is offering to cull invasives from your woodlot. For Free. Oh, and he’s going to use the material to do some Epic Shit. Done deal. I have 3 lots that I am working on this week. The plan had been to drop a bunch of Box Elder since it grows 6-10′ a year here and can be invasive, but that has run into some hitches. First, they are dropping their leaves, and I need the leaf nitrogen in the Midden. Second, the main wood lot was cleared of Box Elder a decade ago. Huh. So the land owner and I walked his lot and it became very obvious that there was plenty of species still in leaf, and the sources were, if anything, even better: buckthorn and honeysuckle which are wicked invasive in this area.
As we were felling these, I became worried that there wasn’t enough green material in the mix – the honeysuckle especially was only leaved on the ends of the trunks due to the dense canopy, and most of the buckthorn we were dropping was crazy mature – we had some with 7″ trunk diameters! Looking around some more we noticed that mulberry was still in full leaf and they are a very aggresive tree in their own right. Out came my new Husqvarna and we dropped several 7″ trees that were leaning over his paths and would become issues in the next decade. These were limbed up, with the trunk being lopped up for firewood. tomorrow, at the property where I market garden we will be dropping a HUGE mulberry that is shading a vegetable patch with the same technique: limbs into the Midden, and the trunk wood will be used for space heating.
The honeysuckle, small buckthorn and mulberry look exactly like the shrubby brush that was coming out in the Jean Pain videos. Still TONS of trial and error to be done here, but it looks like 1″ or less trunk diameter is the money width for composting. The 3 bins I have going at home were built using 1.5-2″ willow and are far too carbon rich; I needed to add nitrogen at the first turning. 1″ trunks would be a 2 year rotation in a willow coppice. I have no idea what pushing a coppice that hard will do, but it is likely it will burn it out in 5-10 cuttings. That said, I was cutting mulberry out of the landowners asparagus “patch” (its .5 acres) that was 6-7′ tall and has been mowed every fall for 15 years. Those stalk were ideal. Hmmm, with stalks that small harvesting gets easier. How about a mulberry/willow/poplar coppice on 12″ spacing and a 25hp straight veg sipping Kubota (sunflower stalks compost FANTASTIC) pulling a two row Gehl sillage chopper… Those things are dirt cheap on Craigslist as no one uses such small equipment any more. Huh.
But for now I am focusing on harvesting from the woods. With about 6 hours of labor in, we have 8-9 piles of brush larger than the dump truck, and Friday I am putting in a full day now that my sawing muscles are hardening and felling a significant amount more. Tuesday will be the final day of prep, and the rental chipper gets picked up on Wednesday at 7am. Goal is still for 2 loads, 8000#’s, of green material. These will go into the plastic tubs for soaking, and then construction begins on Tuesday 10/19! Pics will be up tomorrow night on the brush hogging.
Can we turn the invasive species of today into the carbon sequestering, energy and food producing fuel stocks of the next century? Stay tuned.
Be the Change!
‘Tis fall, the Season of the Soil! With the shorter days, and frosts in Wisconsin Nature is dropping its leaves to blanket the soil and begin to build the humus necessary to protect the future of it’s ecosystems. Mom Nature really knows her shit, and we should listen; if Mom is covering her soil, we prolly should too. Several billion years of evolution are talkin ya know? This will detail how I am prepping the beds in our annual gardens this year. These are the beds I built in June and the majority of the soil was trucked in – it needs some healing. And you know my answer for healing the soil: compost and organic matter.
In future years I may skip the composting, but we still had a bunch of weeds so off to the Hot Composting it goes. Once the beds were clear it was time to add some medicine – comfrey! I have about 6 dozen Russian comfrey plants on property cloned off 2 plants I bought 4 years ago. Comfrey is a wonder plant, full on minerals and excellent food for soil microbes. Here is a shot of my a bit of my comfrey “coppice”, a double row along a 80′ fence line.
The comfrey is hacked done with a sickle and laid out on the beds. Comfrey is a wonder plant, but it can also resprout occasionally. To prevent this do two things – compost when you cut it when its flowering (if you have viable seed like me), and also when using it as mulch, don’t cut the fronds too close to the ground to prevent any chance of re-rooting from any root chunks. Still, you will likely get some volunteers over the years. In the permie beds I encourage this. In the veg garden, not so much. That imposed order is not natural, but its there. Smother any that come up with a mini sheet mulch.
A layer twice this thick could also be used, but much thicker than that and I would be concerned with it going anaerobic under the mulch. Next up I spread nearly finished compost. Actually this is as finished as most of my compost gets unless I am making potting mix; I prefer to leave some un-decomposed organic matter for the microbes to breed on in place. Look at the color difference! In very general terms, the darker the soil the higher the organic matter content. Humus is black.
I had about 1/2 of a yard of compost left for the three beds I was prepping. Dividing it out works to about .6 inches on average. I would prefer more, but with the mulch breaking down all Fall/Winter/Spring I will add another .5″ over time. Final step is to “tuck them in” as Nature intended. In this case its a 4″ (once settled) of well rotted straw that served all summer as the walls of the Methane Midden.
Not quite done. Need to fill the 1′ paths back in with new wood chips. Why? Because choosing to use wood chips on the path was brilliant. It prevents compaction by spreading the load of walking, but it also holds moisture, and breeds soil fungus like crazy, lots of mycelium after only 4 months. Outstanding!
Notice that none of the beds were turned, nor do I plan to turn it in the spring either. Yep – going no till baby! And from a guy with a $4000 rototiller that is saying a lot! A surface hoeing with a 7″ scuffle hoe was done to clear the debris. Once the debris was clear I could see dozens of holes from the deep tilling earthworms. The straw and compost layers mimic natural soil strata: topsoil-> humus -> duff-> mulch.
No till it is.
2011 is going to be awesome!
Be the Change.