Pee-Ponics Flowering - Struvite

[Vlad Jovanovic]

Meir Lazar got me thinking...pee-ponics philosophy...

When he asked how to add P or K to his pee-ponic system(s) for his flowering fruiting plants, I gave him a "standard" answer coming from a organic hydro perspective...Rock of Phosphate, Bone meal blahblahblah...but suppose you were a vegan? Or, the idea of using an unsustainable post peak mineral did not appeal to you? OR, you really were trying to stay within the bounds (of an as of yet non-existent) "pee-ponic philosophy"...Many of us choose not to do things that we are 'philosophically' out of tune with...or at least do them less, and attempt to choose when and why we do them, wisely...

Dosing your system with (N-P-K 11-1-2) humonia in order to get the 'required' or desired phosphates for flowering just isn't an option because of the massive amount of N you would be simultaneously introducing. I'm sure everyone is well aware of why this is bad and whatnot, so we wont get into that here...But, if you could extract all those phosphates, without all the N... that would seem like a mighty fine addition to you arsenal of effluent. It turned out that this wasn't a 'new' idea or anything (but what is these days?), this is what I did...

After researching why my cat gets bladder stones, the idea came to me...I added Mg in the form of Epsom salt (MgSO4-7H2O) to humonia, stired, strained. The white gunk I strained off is drying in the sun. That white stuff is NH4MgPO4-6H20-ammonium magnesium phosphate and is called stuvite (it's the stuff that bladder stones are made of). It is basically a phosphate precipitate. Like the whitish grey gunk (Calcium Phosphate) that builds up in your mineral hydro system over time causing you to have to flush the media...only instead of CaPO4 this is MgPO4...and 'ya made it yourself..!

According to the Swiss, this struvite should have an N-P-K value of 6-29-0 (Mg-10). AND...

...the effluent (liquid) that is left over from the process has a lowered N value, very little to no P value, and a high K value. Seems like a match made in heaven. This should really open up your fertilizing options while sticking to using 'sustainable humonia'...A 3 part hydro nutrient all from humonia. Whoopie!

Struvite dissolves readily in even slightly acidic environments, and slower in slightly alkaline environs. (might be a nice slow release fertilizer for the garden too). [edit. since writing this, I've used the MAP crystals in both the garden as well as in a couple of small bio-ponic test systems. The phosphates appear to be immediately bio-available to the plants (unlike say, bone meal). The potassium rich leftover looks promising, but the weather has precluded me from being able to test that out much on cultivars that are real potassium hogs...So more to come on that next spring/summer.]

I pretty much just did this last night and this morning and am still testing out some details, but it looks promising. I'm keeping notes of weights, measures, time...and should have some conclusions soon. If Meir or any one is interested I can post a 'how to' with details, measurements, and pictures. I'm building a 12 litre 'struvite reactor' out of galvanized sheet metal and pipes I have lying around (cuz I have lots of humonia to process and building stuff is 'fun'). But really all you need is a bowl, a stick, and a piece of clothe...

(and no explosions or highly caustic stuff with this one either...and 'skill level' is as easy as it gets. If you can make sugar cookies, you can pretty much do this. For now, just getting to the idea, seemed harder than executing it).

For the (so far) theoretical math there is this thread...http://community.theaquaponicsource.com/group/chemistry-math-and-aq...

And for some other struvite stuff there is this... one...http://community.theaquaponicsource.com/forum/topics/humonia-and-st...

I'd like to keep this thread (hopefully by culling some of the cream of what comes out of those other two) about how to make and use struvite and the results when used to grow plants...

[TCLynx]

I can't contribute much to the chemistry part of the discussion here but.

My experience from running a pee ponics system for over a year was.  I needed to supplement roughly the same as I did for the regular aquaponics.  That was I needed to supplement potassium and chelated iron.  Of course keeping in mind that my pee ponics system was running on the same hard well water that my aquaponics systems used and there were shells involved as well so pH never really dropped.

Of course the contents of pee are going to vary depending on the diet, body chemistry, and even time of day of the pee donor.  I never had the impression that phosphorus was lacking in urine but then again, I live in a region where phosphate mining takes place so perhaps there is enough of it in the water.  I've never tested for it.

[Meir Lazar]

Hey Vlad, I would love to know the exact methodologies (I am actually a vegan, lol).

I did start looking into putrefying comfrey leaves and using that solution for my plants (so far so good) but I would be very open to trying this method as well as my "green fertilizers".

I am wondering about this method versus hydroponics as far as closed-loop is concerned. If I use this method (peeponic/bioponics) will it require an occasional flush-out of the system due to salt build-up as I have to do with hydroponics? I don't understand what happens to all that unused P/K that is not absorbed by the plants...

I know with ammonia, Nitrites and Nitrates, I can simply measure how much I have in a system and see if I need to wait before dosing, but how can I tell if there is too much or too little P/K. I know the response might be use a EC meter but those only show the amount EC/PPM of any salt in the system, not a specific nutrient. Am I mistaken? Am I over-thinking this?

Thanks Vlad.

[TCLynx]

Meir,

     EC meters are pretty pointless for aquaponics or bio-ponics that isn't using mineral salts.

I know you can get test kits for P that they use for pond culture (usually trying to make sure the phosphorus doesn't get to high and cause big algae blooms) those tests are much like the nitrate tests I guess though I've never used them myself.  However, testing for potassium... I'm not finding a freshwater potassium test quickly.  I have seen a saltwater titration test but have not idea if that would be of any use for bio-ponics.  So I wonder if the soil test kits for potassium might be of use for bio-bonics?

[Meir Lazar]

So the question still remains, will this be a closed-loop system or would there be a build-up of salts over time that needs to be flushed/dumped...

[TCLynx]

Ya know, I don't think there is a problem with salts build up in bio-ponics but I have only run them kinda like aquaponics or very aquaponic like pee ponics.  As in I don't do water changes.  (well at least not on purpose but on occasion a major leak or plumbing disaster has caused a water change in a system over the years.)

If you start doing a lot of supplementing with this or that or using hydroponic solutions and just supplementing with the pee ponics I expect you would need to treat it much more like hydroponics with doing water changes.

In short, it depends on what you are doing or how salty you pee is.  So I don't really know how to answer the question for some one else.

[Vlad Jovanovic]

IDK...I'd imagine that if you run things in a sane manner, you'd be fine. 

The idea behind this struvite thing was to take your one nutrient source (humonia) and sort of divi it up...for use when your plants need it...It's still humonia, just with N-P-K ratios rearranged a bit. That way, you hopefully would not need any other 'foreign' supplements. And you could use the different components, when your plants needed them...

Overdoing anything is bad...heck, just overfeeding your fish can cause you a world of problems...  

[Vlad Jovanovic]

"It's Alive"...

Well sorta...

Here is how I plan to process copious amounts of humonia into struvite...Mechanically speaking... (Meir you can check out the other threads for how/what I did thus far...really all you need is a bowl and a stick. I'm still working on an "optimal" amount of magnesium so as not to be too wasteful/inefficient, but it appears you don't really need to be all that precise)...

 Here is what's under that fancy corn cob handle...

 It's not pretty, but considering what I'll be using it for...All the parts are galvanized (zinc), so it should hopefully hold up OK in the slightly caustic environment.

I'm gonna call it the "struvite reactor", since all our box-o-rocks we cal "bio-filters"...hehe.

You could probably make this out of PVC and plastic, but I had all this stuff lying around already...Making (then hammering and soldering) the cone was probably the "hardest" part.

Everything holds water and works, now just to finish the collection filter portion...and give it a whirl...(it actually spins very, very easilly...and no wobbles).

[Chris Carr]

Oh wow, now I get it! I guess with this design pre-dissolving the Mg salt is important but it is good practice anyway. 

A really cool and simplistic way to mix and separate regardless. Great work.

Vlad Jovanovic said:

"It's Alive"...

[Meir Lazar]

Thanks for the pics and explanations, I'll check out your other threads to get more info on this process.

[Vlad Jovanovic]

Woohoo...this thing not only holds water, but it seems to make struvite too..!

   

[Vlad Jovanovic]

Using 5 grams Epsom salt per litre of humonia, I was able to extract near 30 grams of struvite out of 10 litres of humonia. This stuff is pretty light and fluffy and has a lot of 'mass' for just 30 grams...

Next to see if I can substitute wood ash for the Mg source instead of the Epsom salt. And see where the K will end up...in the effluent or as a phosphate precipitate...

[Chris Carr]

Wow really interesting results. Thanks for the update.

Vlad Jovanovic said:

Using 5 grams Epsom salt per litre of humonia, I was able to extract near 30 grams of struvite out of 10 litres of humonia. This stuff is pretty light and fluffy and has a lot of 'mass' for just 30 grams...

Next to see if I can substitute wood ash for the Mg source instead of the Epsom salt. And see where the K will end up...in the effluent or as a phosphate precipitate...