I decided that it was time to create a new thread for the Upgrade to the PeePonics system.

For more info on the original PeePonics system please see the original thread.
http://backyardaquaponics.com/forum/viewtopic.php?f=18&t=2534
There is info on my original experiments into the safety of urine and how to age it to allow the urea content of the urine to convert to ammonia which kills off e. coli and such.

The new thread is about that barrel system connected to a duckweed pond to provide nutrients to grow a good stock of duckweed.

And a few more pictures.

Love it! I want to do the same with a cut up water bed mattress for a liner.

If you switch away from tilapia what will you do with it, i.e. will any of your new fish (bluegill, catfish, ?) eat it?

BTW do you know where I could get an IV drip connector to slowly drip the bottle into the pond?

Could you use 1/4 inch drip irrigation parts? Available at local hardware stores.

http://www.aquaticeco.com/subcategories/2565/Kent-AquaDose-Systems/kd6/0

This is where I got the replacement hose kit. I just drilled a hole the right size in a juice bottle rather than buying the special jug.

Gotta make sure the cap stays loose on the bottle or it won't drip. Also, need to check and adjust the drip regularly since the solids that precipitate out of urine will clog the hose where it is restricted.

I've found that drip irrigation drippers tend to clog with hydroponic nutrient so I expect would be even more clog prone with hummonia. Then again, if the primary plan is to grow duckweed, daily dosing by just pouring some amount in is probably fine since the duckweed would rather have the ammonia rather than the nitrate. At the moment I'm feeding enough hummonia to keep the ammonia readings above 0 so I don't really feel good about adding any fish to control the bugs. Still got a couple mosquito dunks in that duckweed tank.

I don't know that I will ever completely give up on tilapia but they will not be the primary fish.

I'm hoping that the chickens will take to eating some duckweed. I expect duckweed will also make a good feed stock for worms. Other uses of duckweed might be things like using it in the garden in place of alfalfa meal which I sometimes buy in pellet form to use as fertilizer.

Since I've never seen anybody ask or it mentioned...
What method do you use to collect hummonia?

Rinsed out juice or water bottles. The cook can pee directly into the bottles. I use a funnel.

Well, I wish I still had some tiny little tilapia to put into the duckweed pond to control mosquitos. We just put one tilapia into the duckweed pond. I'm a bit fearful that the water quality might not be good enough for larger fish so we only moved one. Doped her into the duckweed pond and the duckweed closed over and we thought, "how the heck will we check on that fish?"

Would mosquitos mesh over the tank stop them from getting in. I haven't read the part on aging yet. But I liked the idea of setting up a toilet with a small flush that would counter the evaporation in the duckweed pond. Small pipes because it only deals with liquid. Could drain into one container as the second one drips into the pond. And when its empty just switch it over.

You would have to make the screening over the tank quite good to keep mosquitos out. I have shade cloth over it but it isn't sealed perfectly and there are plenty of places for bugs to get in. Ya also want to keep if fairly easy to open up for harvest of duckweed. Duckweed needs harvesting often and regularly to keep producing well and avoid problems.

As to the urine collection. I'm not too keen on the urine separating toilets. We humanure compost and use the sawdust bucket toilet method of collection. A certain amount of urine is needed for the compost. We don't use the flush toilet ourselves, that is for guests not comfortable with the humanure idea. Anyway, It doesn't seem to take that much urine to run a pee ponics system. It really isn't that difficult to pee in a bottle once or twice a day. I don't think mixing it with water before storage would be a good idea since that would interfere with the ammonia concentration that kills off many pathogens.

Much easier to hook up a float valve in the sump to top up the system if/when the water level drops.

When I checked this morning, the tilapia in the duckweed pond is not floating at the surface. That is about all I can tell. Perhaps I need a coffee can with it's bottom cut off so I can place it down into the water to break the surface, scoop out the duckweed from the inside of the can and look around to see if we can see the fish. Unfortunately, the fish would probably swim away to the other end of the tank before we even manage to scoop out the duckweed and that is a pretty small window to find a fish in a 16 foot long tank. (well 14-15 foot long once you figure that there is gravel in the one end around the inlet to stop the water from splashing the duckweed around.

Maybe feed him a little pellet food in the can

Hum, might be worth a try in a few days. I notice that the tilapia are less likely to come zooming to food though and it is living in a pond full of duckweed so has ample food to eat.

Do you have a 14foot length of timber. Use it to move all the duckweed to the side and use a flashlight to spot the fish. Then just stir the duckweed a little to cover the surface back up.

That might work, could probably even manage it with a shorter bit of something.