Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

This one is kind of 'out there' but I could really use some help...

Does anyone know, in practical terms, how one would go about using magnesium, to precipitate struvite out of the humonia, and reclaim your phosphates while lowering N content? I think struvite should have an NPK value of 6-29-0 (Mg-10).

The urinary stones people sometimes get is called Struvite -  NH4MgPO4·6H2O) is formed when urine hydrolyzes to ammonia (usually because of an infection) and raises the pH to alkaline values, then forms a precipitate with magnesium and phosphates. 

The first part (urea converting to ammonia) has already happened just by storing the humonia in a bottle, so we are all part way there already...

 

Now how, and in what quantity to add the magnesium (in what form), and is it necessary to add as much as their is phosphate in the humonia, and how do you know how much that would be (approx) ?

Any help or pointers would really be appreciated, before I start doing this.

Storing the 100's of litres of humonia is getting to be a pain, space wise, and Struvite (which apparently will just dissolve in water later when you need it) seems like a pretty keen thing to have on the farm...

I don't think you'd get any of the potassium to precipitate out, so the effluent that is left over might be a decent fertilizer in it's own right for plants in middle of the fruiting cycle. Plus it shouldn't now plug up your irrigation equipment with precipitates...Again this is the effluent left once you've removed the struvite...

The struvite itself however should be good (like any other high P fertilizer) for seedlings, then flowering stages, and maybe a good way to give cucurbits the Mg boost that they seem to need. ***Edit***(And will, like all phosphate based fertilizers eventually form a precipitate with calcium...like the CaHCO3 in your 'hard' high pH well water. So small misters/sprinklers/emmiters are at risk, but this seasons cheap irrigation tape did alright. No real clogging.)

That's the idea anyways...

Thanks guys.

 

http://community.theaquaponicsource.com/group/fish-less-systems/for...

http://community.theaquaponicsource.com/group/chemistry-math-and-aq...

 

Views: 1898

Reply to This

Replies to This Discussion

trouble replying will try later

Vlad Jovanovic said:

Hi John...thanks for the all the ideas and your kind words...

I've pretty much got the process down to just a few minutes, plus drying (which is also pretty quick depending on the weather) http://community.theaquaponicsource.com/group/fish-less-systems/for...

There are some pics and descriptions in that link. There certainly seems like a bunch of ways you could go about this, and right now I'm happy with the 'reactor'...it's pretty simple and clean. No clogging issues, splashing, (or siphoning with the mouth hehe...) 



gringojay said:



Vlad Jovanovic said:

Hi John...thanks for the all the ideas and your kind words...

I've pretty much got the process down to just a few minutes, plus drying (which is also pretty quick depending on the weather) http://community.theaquaponicsource.com/group/fish-less-systems/for...

There are some pics and descriptions in that link. There certainly seems like a bunch of ways you could go about this, and right now I'm happy with the 'reactor'...it's pretty simple and clean. No clogging issues, splashing, (or siphoning with the mouth hehe...) 

((tying to post this - feel free to paste it in active thread.))

At extraction time hummonia processed at > 10.5 pH yields no struvite, at  > 9.5 pH struvite yield is > 30% less of maximum, at 8 - 9 pH struvite yield is 30% less than maximum purity. At >8 pH the Calcium present  forms up Ca3(PO4)2 & the Potassium forms up MgKPO4;  the closer to 9 pH one's processing hummonia is used the more these solids are the actual precipitate instead of struvite.
If one is not adjusting hummonia pH downward at the time of beginning stirring/processing then the calculation of the end products' phosphate can not assume struvite's phosphate content. At as low as 7 pH it is possible to recover >95% pure struvite, but the rate of precipitation must be slow to achieve this level.
Fresh urine's urea will undergo 100% hydrolysis in 30 days at reasonable ambient temperature. If 25% hydrolysis has occurred it is still possible to extract more than half of the potential struvite. By adding commercially obtained pure enzyme urease at a rate of 50 mg/L(-1) the urea takes less than 2 hours to be ready. Therefore, add >10% aged urine to fresh pee to inoculate with existing urease & then hummonia will be ready for processing after 48 hours, if temperature kept >20*Celsius.

Thanks gringojay. I've taken to leaving in the calcium phosphates and magnesium potassium phosphates...and whatever other precipitates form...since all of these can be plant beneficial. I've also submitted the whole 'harvest' for lab analysis last week to see what all is exactly in there and in what exact amounts. I'll post the results when I receive them.

Vlad, thought you might like to see this... I see a stirring chamber, perhaps doing what you are doing to extract phosphorous?

http://www.youtube.com/watch?v=ke8ZCHFDrGQ&feature=youtu.be

One more thing, did you ever share the results somewhere that you got in your previous post - sending in the precipitates for analysis?

Hi Vlad, I joined this forum purely on the basis of your amazing struvite research and to ask the question, what about the analysis??? Please tell me you have more info to part with?

My interest is in using struvite as a rock phosphate substitute in peat free potting composts. I intend to make my own john Innes compost mixes. I too have extracted 'something' from urine using kieserite but not much success with epsom salts! Perhaps you could reiterate how much of the later you are using per litre please? I intend to run some trials this year using seed and potting mixes but I have to get it out of the urine first and in sufficient quantities to work with.

My last question is, was pH an issue for you? My research has led me to believe that fresh urine has the most struvite to yield so could it be a matter of collecting in smaller batches, adjusting the pH (somehow) and then adding epsom salts/kieserite? I collect in 5L bottles due to convenience (fitting it under the bed etc.!). If fresh is good, do you see a problem in adding the desired amount of epsom salts/kieserite to the empty bottle and then every time a penny is spent giving the bottle a shake until it is filled? This would be easier for my small scale needs.

Look forward to hearing from you with your next update.

Look forward to hearing more, please!

I was saving mine in 2 liter soda bottles.  After about 8 months they began to crack.  Luckily they were not stored under my bed.

Andrew Chapman said:

I collect in 5L bottles due to convenience (fitting it under the bed etc.!).

I am delighted to find that others are using their pee for growing plants! I have been using pee around my garden and yard for years. I use it on tree stumps to help them rot faster and pour it on red ant hills to get them to move. And of course I use it diluted with water for feeding plants. I have not tried it for any Hydroponics / Aquaponics gardens but I am still trying to learn more about them. Can pee be used in the still water raft trays?

Yes, the non-recirculating B.A Kratky set up can use humonia as an input source, but you would still need to 'pre-treat' the water through a biofilter.

Thank you Vlad for this information. So is there any info here about how to pretreat this water?

Vlad Jovanovic said:

Yes, the non-recirculating B.A Kratky set up can use humonia as an input source, but you would still need to 'pre-treat' the water through a biofilter.

Yes, you would filter the water through a bio-filter in much the same way that you would 'fish water'...nothing special 

Joni Solis said:

Thank you Vlad for this information. So is there any info here about how to pretreat this water?

Vlad Jovanovic said:

Yes, the non-recirculating B.A Kratky set up can use humonia as an input source, but you would still need to 'pre-treat' the water through a biofilter.

So Vlad, can you point me in the right direction as to what is the best kind of bio-filter to use for pee water. A bio-filter that would be cheap to make would be the best for me right now. Thank you for your help.

Vlad Jovanovic said:

Yes, you would filter the water through a bio-filter in much the same way that you would 'fish water'...nothing special 

Joni Solis said:

Thank you Vlad for this information. So is there any info here about how to pretreat this water?

Vlad Jovanovic said:

Yes, the non-recirculating B.A Kratky set up can use humonia as an input source, but you would still need to 'pre-treat' the water through a biofilter.

Reply to Discussion

RSS

© 2019   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service