Sciencemadness Discussion Board

Biological oxidation of ammonium/amines

12AX7 - 3-6-2005 at 23:38

First of all, has anyone here tried this? I know it was done quite often before the Ostwald process et al for fixing nitrogen and ultimately producing nitrates.

Yes, I'm seriously considering this...

My plan:
Provide a substrate of say 5 pounds sand, 1 pound clay (I don't want to use too much clay, the stuff I have on hand is very fine, a ball clay), some dirt or manure to culture, anything else?
As the nitrogen (sourced from say, urea) is oxidized to nitrate ions, pH will fall, but so as not to kill the bacteria, an insoluble base is demanded. Local dolomite, crushed and/or powdered will provide the cations, releasing CO2 as the reaction progresses.

After many days/weeks/months of folding air in, water will be added, decanted and potassium nitrate precipitated with help from some potassium chloride. The remaining sludge will be oxygenated and fed more urea to continue the process.
Overall:
(NH2)2CO + CaCO3 + 9/2 O2= Ca(NO3)2 + 2CO2 + 2H2O (or magnesium as the case may be)
So that's ah, 1 kilo of dolomite (assuming no hydrates and good purity) for every 600 grams of urea, producing 1.6kg nitrate at full yield.

Comments?

Hopefully, it won't be too stinky...

Tim

Esplosivo - 4-6-2005 at 00:53

I was already thinking of the process previously. The idea first came from Theoretic, on the thread Creation of nitrates from non-nitrates.

As I described in my post on that thread my intention is to isolate nitrifying bacteria (I'm aiming at Nitrosomonas and Nitrobacter - most common). This is quite easily done by collecting soil samples from places where water is present mostly all-year-round (rare thing where I live, but I know of a place). To the soil samples a mixture of nutrient media with varying concentrations of ammonium salts and another of nitrites will do the trick. Certain large conc. of ammonium and nitrite salts will tend to eliminate other microorganisms. After small colonies are formed, streak-plating will follow (you can carry this out on some jelly with added Vitamins and nutrients, or else on agar media). After isolation, the two species will be embedded in alginate to immobilise them. The beads can then be placed in PVC pipes, through which an ammonium salt solution is circulated (containing some other nutrients) and thoroughly oxygenated. I was thinking about adding a certain concentration of calcium hydroxide periodically (although I think other bases may also be used).

I have what I need. What is keeping me from starting this project is the fact that I don't have any idea on how to sterilize the air which must be bubbled through the solution. (Such bacteria need lots of air for oxidation of the ammonium and nitrite salts.) I was tempted to bubble the air through chilled absolute ethanol, although most microorganisms will still manage to pass most (I hope) will perish there.

I hope this helps.

12AX7 - 4-6-2005 at 02:28

Thanks, I might try peat for the culture or substrate. LMK how the petri dish stuff goes...

Tim

neutrino - 4-6-2005 at 05:21

You may find this useful. It’s a guide on nitre beds from the civil war era.

12AX7 - 4-6-2005 at 12:28

Thanks, I've read a page very similar to that (almost verbatim, actually) as well. All those animal and vegetable remains must have a terrible smell, we don't have much backyard so I'd probably have to do this in the basement. That's why I want to try to optimize it and use purer materials such as urea (which I believe is still quite available, in lieu of AN these days).

Tim

Pyridinium - 5-6-2005 at 09:10

Quote:
Originally posted by Esplosivo
As I described in my post on that thread my intention is to isolate nitrifying bacteria (I'm aiming at Nitrosomonas and Nitrobacter - most common). This is quite easily done by collecting soil samples from places where water is present mostly all-year-round


Or you could get hold of some water from an aquarium that's been left to stagnate with the pump and filters off for a while. I've read that the ones responsible for nitrate production in there are Nitrospira and Nitrosomonas. I read on another site that some shrimp living in a sea-water tank can also help the production of nitrate. Not sure why.

There are buffers made for aquaria that won't kill these bacteria. I found one from a google search that is pH 8.3 and is used for this purpose. It's called Waterlife. This could keep your pH from dropping due to the consumption of ammonia.

12AX7 - 13-6-2005 at 13:59

Well I picked up some urea today (no one told me it smells, I assumed it was a hard crystalline substance! :) ), mixed 300g with 700g CaCO3 (200g more than stoichiometric, of local limestone/dolomite broken down to -2+8 mesh), an approximate double volume of vermiculite (coming to around 120g), a few handfuls of sand and an unmeasured amount of water (enough to wet it). I then added some sludge from the ground salt leachate solution which has been sitting around for a while, hopefully as a culture. I will stir and fluff daily and guesstimate the progress as it goes, based on dissolution of the limestone and increase in weight. If no progress is had in say, a week, I'll add some fresh dirt.

Tim

12AX7 - 17-6-2005 at 17:39

Update:
On disturbing, it makes the bubbly sound of CO2 bubbles breaking, so it must be working. :D

No sign of wear on the limestone bits yet.

Tim

Quince - 18-6-2005 at 18:18

Quote:
Originally posted by PyridiniumOr you could get hold of some water from an aquarium that's been left to stagnate with the pump and filters off for a while. I've read that the ones responsible for nitrate production in there are Nitrospira and Nitrosomonas. I read on another site that some shrimp living in a sea-water tank can also help the production of nitrate. Not sure why.

There are buffers made for aquaria that won't kill these bacteria. I found one from a google search that is pH 8.3 and is used for this purpose. It's called Waterlife. This could keep your pH from dropping due to the consumption of ammonia.

I have an aquarium, and I can tell you that with every weekly partial water change, I'm throwing out three gallons of water with 50 ppm nitrates. You can isolate a huge brown mass of nitrifying bacterial colonies by wringing out the filter sponges, or using a gravel-vac type syphon on the bottom. Most aquarium colonies are established by bacteria that initially come from the air (the tank is usually cycled to achieve stable levels BEFORE the fish are added). If you don't have an aquarium, you can buy nitrifying bacteria in a bottle (such as Cycle). There are other things in that solution added to help these bacteria outcompete less wanted ones.

The optimal way to get these guys to work is trickle filters (such as those that use sand or bioballs as a medium), because of the large surface area exposed to a constant flow, and large water/air interface. There is no sterilization needed.

Here's an example that will give you the idea:



You can build a container or use a small old aquarium, and then you just need a cheap water pump to suck water from the bottom and pour it on top. Bioballs can be found cheaply and work better than sand (and also the grid keeping them above the sump doesn't have to be extremely fine, as sand would tend to fall through).

[Edited on 19-6-2005 by Quince]

12AX7 - 13-7-2005 at 04:07

Well, it's been a month. I've got a bucket with rounded balls of claylike material (I've been rolling it around for aeration). Any suggestions on 1. isolating remaining urea 2. isolating any calcium nitrate 3. any side products?

Tim

12AX7 - 18-7-2005 at 07:06

So no suggestions whatsoever?

chemoleo - 18-7-2005 at 15:06

Did you do a test on the nitrate content?
If not, I'd suggest to see whether nitrate was produced in the first place. I seem to remember one test was with some iron complexes.

Also, isn't nitrate produced in horse manure? Why not grinding this up a little and mixing it thoroughly with your mixture, to let it sit outside for a long time, while keeping it wet?
Any unreacted CaCO3 and manure bits can be filtered off. HOw to separate the nitrate and urea from each other is more tricky. KNO3 isnt that much soluble, so that may be a possibility.

12AX7 - 18-7-2005 at 18:10

Well as I mentioned, the mixture started bubbling some after I added some sludge from the ground leachate solution, so it probably worked. If not, I'd like to seperate the unused urea (and if possible, without destroying the bacteria and substrate as well, for convienience) and what calcium nitrate has formed, so as to figure a rate of progress.

FWIW, the mixture has formed some fine, hairy, acicular efflorescence between the nodules.

I'll try a natural substrate such as "black dirt", manure and whatnot next, if the yield on this method is low.

Tim

12AX7 - 28-8-2005 at 18:48

I wetted it down, settled out the vermiculite, added some dirt, and a circulating/bubbling pump since it's now in liquid form. It smelled strongly of ammonia (say, how fast and in what environment does urea hydrolyze to ammonium carbonate anyways?), so I added some acid (HCl and H2SO4) until it smelled again like plain urea. Bubbling ensued, CO2 I would guess. Not from the limestone chips in the bottom.

Now it's keeping a constant foam, I'm *guessing* it's got something growing and pooping in there... I was going to take a sample some day, add muriate of potash, boil then near freeze it to see if anything falls out. What's the solubility of KNO3 at 0C anyway?

Tim

12AX7 - 27-8-2006 at 14:22

Bump.

So in case anyone was wondering, it looks like I never mentioned what happened. After all the blah and hydrolysis, I crystallized the solution, resulting in blocky, large, clear crystals (I'm guessing ammonium sulfate or so), followed by (trying to remember) dendritic crystals I think (ammonium something?), blue or green tint (complexed trace metal impurity?), and very cold when dissolved in water. But not cubic like ammonium chloride, of which some did show up later, in green (iron impurity?) cubes which don't really melt but do boil a lot on heating. Also some blue specks that seperated I think from the dendritic crystalline material after recrystallizing a few times, don't know what those are, lastly some white, translucent, easily crystallized salt that I haven't analyzed; plus some sludge that is too little to bother crystallizing.

My newest attempt (a month or two old) involves composting grass clippings, urea and dolomite gravel. I've kept it under shelter, so it doesn't get wet but has free access to air. At first it wasn't doing much, but I think for the last month it's been chronically moist, which I can only assume means there's something hygroscopic present. It smells of some nasty decomposition, so something's going on, at the very least. The sludge is dark, more or less black. I suppose I'll analyze it when the weather starts getting cooler.

Tim

not_important - 27-8-2006 at 22:31

Some organisms produce urease, which hydrolises urea to ammonia and carbon duioxide rather quickly. As both products are gases, they tend to soon leave the scene, removing your nitrogen source.

This gives a decent description of aquarium nitrifying bacteria
http://www.bioconlabs.com/nitribactfacts.html
http://www.pwri.go.jp/eng/kokusai/conference/komori010825.pd...
They only need inorganic nutrients, not having organics around reduces nitrate lose through denitrifying bacteria.

These bacteria need a lot of oxygen, grow slowly, are picky about pH, and so on. Rather than throwing all the urea at them at once, I suspect you would get better yields by applying small amounts daily in dilute solution.

The aquarium route might work better than a wad of rotting stuff, even more a tank filled with coarse, sharp edged sand that has aerated nutrient solution pumped over it. The bacteria grow on the surface of the sand, so the more surface the faster the overall conversion.

There is a limit to how much nitrate will be tolerated. In the old methods of nitrate production, the piles of rotting matter either lost the salts through oozing out the bottom, or evaporation on one or more surfaces - concentrating the inorganic as a crust. There's no easy way to pull just the nitrates out. I think that you will end up removing a bit of liquid daily to let evaporate, and replace it with water containg the proper amount of urea and phosphate.

Quince - 27-8-2006 at 22:41

I keep throwing out good deals of nitrates when I change aquarium water, but I don't see any efficient way of extracting given the low concentration (since I keep fish, I can't allow the water to reach more than 50 ppm nitrate content).