Backyard Aquaponics
A place to discuss aquaponics

Holy cow, haven't read your thread for a couple of weeks DD, you've been busy....

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www.backyardaquaponics.com
Bringing Food Production Home

Nice work Dave. From what I can see, your running two pumps. Or rather, have two and running one into the solids digester? Do you anticipate any manual solids removal from the digester?

The digester, lagoon, and 110 gallon sump/DWC/whatever tub will all run from the one pump. For now the gravel tub uses a sump pump. I'm not sure yet how it will expand, but I plan to add some kind of long bed/trough in front and hanging features toward the other end.

This weekend was another busy AP weekend, more pictures tomorrow but for now here are pictures of the first trash can (wheelie bin) put into the second, which is a 44 gallon Rubbermaid Brute. The Brute is tough and rubbery, and the gray ones are food safe so that's nice.

I just cut the rim and handles off the round wheelie bin, so that it would fit snug all the way to the bottom of the bigger can. I drilled holes around the edges for water to go out from the center. Another way would be to sit the can on some kind of spacers, to make a gap at the bottom for the water to escape. A small spade bit worked best, and with plastic it goes better if you push slightly when the bit is slowing down.

Four air stones will be hanging down from the top, the plan is to feed the tubing until they just touch the bottom.

Also got the lagoon in place, more pictures tonight.

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DD's Landing Page

The idea here is that the water from the FT feeds in to the center, which is aerated with lots of bubbles, which churn the solids and let the bacteria work on them. The water comes out through the bottom holes to the outer edge of the larger can. The gap between the inner and outer cans tapers, similar to a cone, hopefully encouraging solids to stay settled at the bottom, and maybe get re-circulated into the center. The outlet is just a simple electrical fitting on the outer can.

I do plan to add some piping to allow solids to be drained out if necessary, but I'm not going to add it until I need to. I may want solids to water other plants outside the system for example.

I may need to throttle the flow back if the solids aren't staying in the can, or maybe use two to split the flow?

Also got the lagoon in place in its frame, more pictures tonight. Air pump backup, some plumbing details (glue!), and fail-safing the system will be next I think. Cold frames on the lagoon and sump too, although if I wait long enough might not need any! Today it was 65F/18C!

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DD's Landing Page

Indoor plants from the Rendezvous system, parsley is big, cilantro/coriander is viney. You can kind of see the basil looking droopy. Need to make some pesto this week.

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DD's Landing Page

Outdoor system, pump up to the solids digester, split to lagoon and sump, then back to FT. Gravel tub on timed sump pump.

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DD's Landing Page

Do you have any system in place to remove methane if it is produced?

You have been busy, nice work. Clarify for me if you will Dave. The rectangular tank snugged up in the corner, you call the "lagoon?" Will that be a growbed?

The solids digester looks good. If the FT pipe flows downward into the center of the black inverted barrel, will it not force the solids out of the bottom (drilled) holes? And up out of the grey tub? Not sure, just asking.

Hey peeps:

I would hope methane is not a problem, if you're talking about in the digester thing this will be aerated a lot - I hope to not have any anaerobic digestion going on in there.

The lagoon is to set planters in, rotated in and out as with the indoor "rendezvous" setup. I have some 5 gallon buckets, big planters, medium planters, and a couple of those rubbery basket things with handles that you see around at Walmart etc. for gardening. Those were $10 a pair at Sam's Club and they are almost as big as the 18 gallon round laundry tubs. May also use those. The planters will be set into the lagoon for awhile, and rotated out to the deck or yard, etc. as needed. Eventually I will add more dedicated beds but to start there will be these planters and the DWC tub, probably for lettuce etc.

Good question about what the solids will do, we will see. I can bleed off the flow a bit and/or add a second one if the solids don't stay put.

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DD's Landing Page

Re: the solids escaping, the gap gets wider as the solids travel upward (just like a cone does), slowing them and hopefully settling them back down. This depends on the flow and the solids though. If they don't stay in there the flow could be reduced, the gap could be redone so it's wider at the top (more of a cone), or I could punt and drain the solids from time to time.

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DD's Landing Page

Hi Dave,

I took into account that you are running aerobically when I asked the question about methane. The reason I asked is that I thought you might run this on a separate air pump - if the pump stopped working you might not catch it since it looks like everything is covered. Then of course things would be anaerobic. I would just leave it a little "leaky" around the pipe at the top and don't light any matches when you want to look down in there and see why it's not working . Might take a while for your eyebrows to grow back.

Thanks for the comment, the pipe hole is not totally tight, I have minimized the pipe hole size in the upside-down can because I wasn't sure how close to the top the water level would be. It seems there is plenty of clearance, so the whole half-moon shape on top may be removed. There will be holes where the air lines go in too.

The plan is to have an air pump on battery backup, one air stone in the digester. But thinking about power outages and too much flow, maybe it could be setup with a "weep" hole, that drains back to the FT. If the power went out then the digester would slowly empty to the FT, leaving the solids in air. It wouldn't be nice to have the digester full of water and no air, for sure.

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DD's Landing Page

Any place other than the fish tank you can put the weep hole to? I was thinking that any solids going back to the fish tank during a power outage could eat up oxygen.

I think with the gaps around the openings you should be fine as far as methane buildup (since methane is lighter than air it should go right out the top) so I wouldn't put the weep hole in at this point.

It's good to think about the failure modes, that is what I'm supposed to be doing ATM before getting the fish. I wouldn't want the anaerobic sludge to go to the fish in a power outage, to be really safe maybe for a power outage the digester would drain to some tub not connected to the system, like another sump with its own little pump. I don't plan on anything like this yet though.

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DD's Landing Page

Oh so sore tonight - almost done putting together a cold frame for the shallow tub. Splurged and got some polycarbonate panels for it! So exciting!

The basil seems to be droopy because it is getting dried out too much, after the plants have been put in the system they perk up again.

Moved the biofilter for the aquarium directly under the outlet from the solids digester, I will need to do something for the plants to get the water, probably will just take water from the system and top up with clean, until I can get a lagoon set up in front of the window. Would like to use the bigger 30 gallon aquarium downstairs but it is way dirty.

Does anyone have experience cutting polycarbonate panels?

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DD's Landing Page