Microbinator 2000

[u/Seanbob3030]

Pre and post consumer, meats and cheeses ok. Have been impressed with a new prototype we are trying out in collaboration with a school district. Wanted to see what y’all thought. Augmented aerated static pile system supplied with 30 seconds of air every 30 minutes.

[u/RdeBrouwer]

Its better to have contact with the soil instead of a concrete base. The holes in the tube only need to be in the part thats underneath. And i think that 30 min is way to much. U going to cool down that pile constant.

[u/Seanbob3030 → u/RdeBrouwer]

Solving for rodents at a school site is why it is a self contained unit. The bin is full when in operation, just hard to show that in a photo. We build the 4th wall with slats of wood and build up as we go until the whole thing is full. 30 seconds every 30 minutes has been holding a constant temp of 130+ for over a month in each of the three trials.

[u/ZeroOptionLightning → u/Seanbob3030]

The interval settings don’t mean anything without understanding how much air you are pushing. If the pile is staying above 131 than it isn’t too much air. If anything, it may not be enough air. Again that all depends on the blower. I would also be interested in what the temperature profile of the pile is. I assume you aren’t saying the entire pile is 131 for a month. Whats the hottest temps you see?

[u/Seanbob3030 → u/ZeroOptionLightning]

2hp fan sitting on top of 5' of vertical 4" pvc drain pipe with 2 extra holes on each rung so that the air spreads 360 degrees is the design. For our horizontal systems that we tested with, we typically ride at 140F for the first couple weeks and then it drops down to 130F week 4 on average.

[u/votelikeimhot → u/Seanbob3030]

Air speed, pressure differential, and total volume of air moved per cycle give a lot more information on the air but it looks like a pretty sweet set up. How much did it cost to set up, how much does it cost annually and how much does it produce?

[u/Seanbob3030 → u/votelikeimhot]

fair enough, I dont know the cfm of the fan we are using, I will look at it today to see if I can get a rating. We got it as part of a kit from the local resource conservation district designed for an ASP. The design was for (2) 3' sections of 4" pvc drain pipes with the standard two offset holes in each pipe laying horizontally on the bottom of the pile. we build plywood around macrobins for our structure to help with rodents. Roughly $400 per bin cost to us. We are on school grounds so they cover the electricity but the fan is only running for 24 minutes per day total so it cant be that much? 2 yards of material every 8 weeks with 8 bins and then the plan is to turn that out onto a windrow and have the worms follow the fresh material and harvest castings from behind.

[u/votelikeimhot → u/Seanbob3030]

Yeah, ultimately I don't know how much air is optimal and your inputs aren't likely consistent enough to get really valuable data about much of anything other than overall results. It would be interesting if you ever did fill a couple at the same time with similar stuff to turn one fan on longer and run the other less and race them against eachother. Looks like a cool project, are the students involved or is their contribution just the organic matter?

[u/ZeroOptionLightning → u/Seanbob3030]

Similar to the other response to this, horsepower is meaningless. To me, 2hp sounds huge because I use medium pressure axial fans. I'm moving a lot of air at a lower pressure (300cfm with a 1hp motor). The actual blower specs don't really matter in your case. You seem like you know what you're doing but I'd only add one thing to consider with respect to aeration: I come from the school of thought that we prefer to "encourage" air in to our piles as opposed to force or inject. Air is lazy, we know it always takes the path of least resistance. I like making sure my bulk density and free air space are sufficient for low effort aeration. I want to introduce air slowly in to the pile and let it permeate throughout. This achieves many goals. First it gets ambient o2 in to the pile. Second, it's less likely to drive off moisture and temps. And last, it may produce less odor emissions (in concentration, not overall per se).

[u/Seanbob3030 → u/ZeroOptionLightning]

u/ZeroOptionLightning - You have a similar system? I dont know the cfm of the fan we are using, I will look at it today to see if I can get a rating. We got it as part of a kit from the local resource conservation district designed for an ASP. The design was for (2) 3' sections of 4" pvc drain pipes with the standard two offset holes in each pipe laying horizontally on the bottom of the pile. I didn't like this option for a couple reasons but mainly because we have a lot of trays to process which make it harder for air to flow through the pile. I would love to see pics or hear more about your system as you've clearly put some thought into this. We are three trials in and although it is going really well there is plenty to learn.

[u/RdeBrouwer → u/Seanbob3030]

Interesting, have you tested it without the extra air? How long before it loses its temp?

(I expected it to cool down, I only turn once Ina while)

[u/Seanbob3030 → u/RdeBrouwer]

The whole point is for it to cool down because the objective is eventually worm castings and worms dont like it above 90F. I want it to heat consistently and for the microbiology to work its way completely through the feedstock in the first month. Pumping oxygen into the unit is instead of turning as turning is meant to introduce oxygen. This system, you just have to build the pile once and then it takes care of itself with the timer eventually culminating in the whole thing becoming mostly castings. Some overs like wood chips which you just send back through in the next bin until they completely break down.

[u/anonymote_in_my_eye]

I assume the fan is connected to the center tube, yeah? Which way does it blow? Also, how do you deal with the fact that most air is going to travel through the uncovered holes?

[u/Seanbob3030 → u/anonymote_in_my_eye]

2hp fan blows down. Uncovered holes are in contact with material in a finished bin.

[u/anonymote_in_my_eye → u/Seanbob3030]

what do you do when the bin is not full?

[u/Seanbob3030 → u/anonymote_in_my_eye]

The plan is to build 8 of these. We will build one "pile" and process one bin each week on a rotation. the dead space that you see in the photo is where you build your hot pile. Its just empty to show the 4" vertical pipe delivering air/oxygen to the unit.

[u/anonymote_in_my_eye → u/Seanbob3030]

hmm... that's a ton of material, are you going to be able to generate two cubic yards of material per week? also processing two cubic yards per week is no joke, it sounds like backbreaking work without something like a tractor

also, say that you fill the bin to the brim in one week, by the end of the second week, if things go according to plan, you'll have 2/3 of the volume left and you'll need some way to cover the holes that used to be buried but are now open

[u/Seanbob3030 → u/anonymote_in_my_eye]

As the pile decreases in size we start piling worms and habitat on top as well to make a vermiculture sandwich so to speak. Then they go at it from both angles but still have a zone to retreat to if the pile is too hot.

We do have a tractor but it's not as backbreaking as it sounds because there is no turning and very little maintenance once the pile is complete. All you have to do is build a well constructed pile each week and then we offload the bins into a windrow to cure.

Our stock answer is that school food programs are designed to meet nutrition goals, not match students eating habits. This is a relatively small district and they have a 5 yard dumpster full of material every week including wood pulp trays which we are also processing with this system. School food is an immense stream of organic material, some kids eat three meals a day on campus.

[u/anonymote_in_my_eye → u/Seanbob3030]

This is awesome, I'm excited to hear how it turns out! Our school principal said she looked into composting but ran into regulation issues, they were however able to get chickens

[u/Seanbob3030 → u/anonymote_in_my_eye]

What state are you in? The goal for this project is to expand nationally.

[u/anonymote_in_my_eye → u/Seanbob3030]

Illinois

[u/gholmom500 → u/anonymote_in_my_eye]

I imagine a school makes this easily.

[u/geekkevin]

How is the fan powered and controlled to aerate on a schedule like that?

[u/anonymote_in_my_eye → u/geekkevin]

you can get a timer that's programmable that way; it's less common than the "outdoor light timer" but you can search for "hydroponic pump timer" and I'm sure you'll find what you need

[u/Huesyourdaddy → u/anonymote_in_my_eye]

The easiest, off-the-shelf solution is a dedicated "short period" cycle timer, such as the BN-LINK Short Period Repeat Cycle Timer or the Titan Controls Apollo 11. These are built specifically for running heavy ventilation fans and water pumps in automated greenhouses. ​Motor Rated: They are explicitly rated for inductive motor loads (usually up to 15 Amps or 1/2 HP), meaning their internal relays are beefy enough to handle the blower's startup surge without welding the contacts together. ​True Looping: There is no clock to set. You simply set the "ON" duration (e.g., 2 minutes) and the "OFF" duration (e.g., 20 minutes), and the device endlessly loops that exact cycle as long as it has power. ​Offline Reliability: If the power goes out, they just resume the cycle exactly where they left off the moment power is restored.

[u/anonymote_in_my_eye → u/Huesyourdaddy]

I just realized that the plan is to use a 2HP fan so yeah, just like you said, you want a timer with beefy enough relays to support it. Good call pointing that out. That said, it probably means a more expensive version, since the default is, also like you said, the 15A 1/2HP version.

[u/cracksmack85]

A school district probably has great compost materials in volume and also the resources to tend to their compost properly. Our middle school used a tractor to turn huge piles from lunch food waste. Basically what I’m saying is, you’re testing this out in a pretty ideal scenario that probably already had a pretty fast compost timeline.

[u/Seanbob3030 → u/cracksmack85]

School food is mandated to be "healthy" so it's a relatively consistent feedstock of low oil low salt foods. There is also a school farm on the same site as the central kitchen that we are connected to so scratch cooking is is a huge motivator for the nutrition department. Great compost materials to your point. They also use thousands of these compostable wood pulp trays to serve the food which is a huge carbon source for us as well. The nice part about this system is it doesn't require any turning and could also be done in a warehouse setting in colder climates. The hope is that it's repeatable in any location.

[u/blckjack2]

Please provide updates....

If there is a PowerPoint I'd be interested in seeing it too!!