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Step 2: Design & Setup

Again these instructions assume you already understand composting and building a compost building. For this project I recommend that your compost bin to be no smaller than 27 cubic feet, or roughly 3 feet wide X 3 feet deep X 3 feet tall and that you have two of these bins that are undercover or can be covered securely with a tarp to control moisture levels.

The set up I am working with up is a 7 foot wide X 15 feet deep X 5 foot tall with a 12 foot roof roughly the same width and depth as the average parking spot . By dividing this space in half, this will allow for a two bin system , each bin roughly 3.5 feet wide X 4 feet tall X 12 feet deep, with a rough capacity of 144 cubic feet per bin, which is generally just enough space for a months’ worth of horse manure for 2 large horses or 3 small-medium horses.

Once you have determined the permanent location and dimensions of the bin, map out the best and most efficient location for pipes to be laid.  When filled all of the compost should be within 18 inches of a pipe.

For me this was simple, just single, straight pipe the length of the bin. As the bin was 3 1/2 feet wide, the single pipe  down the middle, would be perfect.

Heated air will naturally rise so incorporate vertical chimney pipes help to aerate the upper layers of the pile and help to distribute heat more evenly through the pile. The chimney pipes will also help to direct moisture down deep to the center of the pile instead of lingering in the upper, outer layers.

When designing the system, try to keep the lengths of pipe the minimum distance you can. If your blower is 35 feet from the compost pile the force of the air will not have adequate pressure to push the air though the compost properly.

Design your system so that the pipes are cyclical or capped to help keep the air pressure up and the air directed properly.

Determine the size of PVC pipe you want to use. For small bins, less than 50 cubic feet in volume I recommend using 1 1/2  inch PVC pipe but anything larger I recommend 2” PVC pipe. I am using 2” PVC pipe in my setup.

For this build I used my leaf blower that I bought for $30 at Home Depot. It’s a no name brand that you can probably find for even cheaper on eBay. This blower is great for 18’ – 24’ feet of pipe. If you use more than 24’ feet of PVC pipe you’re going to need a blower with more power. I would suggest looking in to using a hot tub air blower.
<p>Hi, we have built 3 bays in anticipation of fitting the pipe work. It is difficult getting 2&quot; waste pipes, the standard being 40mm (1 3/4&quot;). could you advise me on the layout of 40mm pipes in each bay? we were thinking of 6 x 1.3m (4 foot) high 40mm pipes per bay, driven by a leaf blower. Given the length of the pipework, would you suggest anything more powerful or is this enough? a lot of interest being shown on Facebook by our construction! kind regards, Clive</p>
<p>i've got 100' length or 3/4 pex left from a remodel.... thinking of how i could use that coil maybe just suspend it. any thoughts? anyone?</p>
vespaskank, you gave me a good idea regarding ordinary electric blower instead of electric motor! Thank you. I'm a guy from cold =)) and distant Russia :P <br> I surfed internet and found that : <br>1) the microbes could require a volume of air &gt; 20 times the volume of compost, every hour (look at the pic with pyramid and notes for it at this link: http://www.magicsoil.com/Research/) <br>2) the oxygen level in the pile drops off very quickly - often to less than 1% within 30 to 45 minutes (source: http://www.o2compost.com/content/Secret.htm) and the previous source says that oxygen drops down even faster - in 15 -20 minutes. <br>I have a plastic container of 1 cubic meter, so I suppose that every hour I should blow in 20 cubic meters in the container. it's easy to calculate that if I have , for example, a blower of capacity 228 m3 in hour tha means I should use it 5.2 minutes in hour. + it's essential to divide this 5.2 minutes to have 4 breaks of about 15 minutes or a bit less. <br>3) It seems that volume of blown in air depends on the moisture content in the compost components....and it often happens that 20X (to a compost's volume) volume of blown air inside can dry the compost a lot. and what if I have a chance to water a compost once a week ? Should I reduce blown air? I think so. But in this case what's the point to blow the air inside if we have 50% of the whole composting period CO2 existence (= anaerobic bacterias) inside. Productivity in this way fall down to 1/2. <br> <br>May be it's better to make a &quot;skeleton&quot; of drilled and connected vertical and horizontal tubes inside the composter and regulate the draft (it's created by heat that's done by bacterias, it's a bit more advanced than guys do in Aerobin 400 ) (you can look at Aerobin here: http://eartheasy.com/yard-garden/composting/aerobin-400-insulated-composter-15-cubic-foot-133-gallon-compost-bin ) <br>I still have a question - Is it possible to regulate the speed of air flow/ time of its work properly not to dry the compost and have FAST composting speed. Or it's better to make a passive ventilation with tubes (I mean for summer season use)? Do you have an idea/ experience of your own? Thank you ! <br>;) <br>
Very good project, congratulations!
Thank you for you feedback!<br> <br><br> <br>Step 10 <em>&quot;Setting up the automatic timer&quot;</em> briefly talks about timing:<br> <br><br> <br><em>I recommend starting out with twice a day for 5 to 15 minutes, it depends on the timer you bought and the settings you have available. Originally I had a fully adjustable timer and had it set, to run 10 minutes 4 times a day but I found it dried out quickly and it never maintained a core temp of 140 degrees.<br> <br><br> <br>Through trial and error of compost troubleshooting I&rsquo;ve gotten adjusted to work for twice a day for 15 minutes and it now it keeps a good moisture level, no smells or odors and has a consistent all over temperature of 140 degrees which means good microbe activity.</em><br> <br><br> <br>More specifically <strong>Ismith254</strong>, I've found the you may have to change the frequency depending on the weather, for example I live in Seattle where it rains a lot even in the summer and even though my piles are covered there is some leaching and leaking, so I find that if I add another internal of even 5 minutes it will help to aerate and dry the pile out enough to keep the balance I need.<br> <br><br> <br>Again it really is troubleshooting and trial and error based on your setup and the number of holes in your pipe. For some people and climates every other day for 5 minutes will be enough, and for others 2-3 times a day for 5-15 minutes may be better to keep the right balance.<br> <br><br> <br>Just play with the time and moisture levels until you find out what keeps your compost thermometer at 140 degrees continuously. Hope this helps!<br>
Thank you, somehow I missed that part. Thanks for sharing the knowledge!
I scanned through everything, and could not see anything about how long you leave the blower on? Is it only for a few minutes a day? Thanks!
Thank you for you feedback!<br> <br> Step 10 <em>&quot;Setting up the automatic timer&quot;</em> briefly talks about timing:<br> <br> <em>I recommend starting out with twice a day for 5 to 15 minutes, it depends on the timer you bought and the settings you have available. Originally I had a fully adjustable timer and had it set, to run 10 minutes 4 times a day but I found it dried out quickly and it never maintained a core temp of 140 degrees.<br> <br> Through trial and error of compost troubleshooting I&rsquo;ve gotten adjusted to work for twice a day for 15 minutes and it now it keeps a good moisture level, no smells or odors and has a consistent all over temperature of 140 degrees which means good microbe activity.</em><br> <br> More specifically <strong>Ismith254</strong>, I've found the you may have to change the frequency depending on the weather, for example I live in Seattle where it rains a lot even in the summer and even though my piles are covered there is some leaching and leaking, so I find that if I add another internal of even 5 minutes it will help to aerate and dry the pile out enough to keep the balance I need.<br> <br> Again it really is troubleshooting and trial and error based on your setup and the number of holes in your pipe. For some people and climates every other day for 5 minutes will be enough, and for others 2-3 times a day for 5-15 minutes may be better to keep the right balance.<br> <br> Just play with the time and moisture levels until you find out what keeps your compost thermometer at 140 degrees continuously. Hope this helps!<br>

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