Monday, October 7, 2013

Hope on the composting front: from the desert?!?

This paper:
Integrated biological treatment of fowl manure for nitrogen recovery and reuse
in Journal of Environmental Management 117 (2013) 172e179
by Roy Posmanik, Ali Nejidat, Boaz Bar-Sinay and Amit Gross
(link to paywalled paper)
Shows some amazing results from a relatively simple system: a net uptake and conversion of 40g of ammonia per cubic meter of biofilter per hour. (The latency for conversion is not explicitly covered, but the description of the measurement process leads me to infer it's on the order of hours or perhaps a few days.)

First, Kudos to the authors. Great project, nice work. Particular merit for the explicit publication of the values in Table 3. That is (often enough) the value people are seeking in systems like this, and too often it is glossed over, left as an implication, or omitted altogether. Well done.

The bad news:
The process itself is patent-encumbered, so perhaps not generally available.

I publish these questions in the hopes that they will spur other people's brains as well.

Questions about the text of the paper
  1. The text says "The NU was composed of six opaque PVC columns (120 cm long and 15 cm internal diameter) filled with a mixture of 10 L mature dairy manure compost [...] and 10 L plastic beads". Can I read that as "... EACH filled with a mixture..."? It would seem to make sense, since the dimentions specified would give a volume of just over 20L, so filling them with 20L of material individually would make sense.
  2. What is the significance of "Mature" in the phrase "mature dairy compost"? I am familiar with cow manure, but this sounds like something different.
  3. The initial pH and electrical conductivity are given, but not referred to again. Is there a significance for this data?
  4. The apparent inputs to the NU over the experiment are:
     1L/column/day of water
     15L/min fresh air (per column or per NU?)
     5L/min ammonified air (Per column or per NU?)
  5. Table 1 lists a variety of Nitrogen values. Are these values totals over the course of an entire run, or per day, or per...?
  6. Table 1 lists "Residual N in biofilter". Is that non-nitrate N? How is it different from "Recovered N in fertilizer"?
  7. Early in the text, reference is made to the water added to the NU as "maintaining moisture content", but later there is another: "rinsing the biofilter" (to remove nitrates). From the first I had assumed that the excess water was lost as water vapor through the ammonia trap. From the latter it appears that the water was recovered in some way. More details on the water exiting the system would be most welcome.
  8. In the text regarding Table 3, the text reads "(mainly as NO3)"...what were the proportions of NO2, NO3, NH4 and Organic-N in the resultant compost? If "mainly" means 40% NO3, it's different than if "mainly" means 97% NO3.
  9. The text gives numbers in terms of cubic meters of biofilter. Biofilter is the 50/50 volume mix of manure and aeration balls, correct? So the experiment overall would have been about 120L total, or 0.12 cubic meters, right?
Questions about the experiment and outcome
  1. Is there a maximum (practical of effective) NO3 load for the compost? In other words, how long is it practical to run this process between leachings or manure compost replacement? Surely at some point nitrate toxicity will diminish the absorption capability of the compost.
  2. The text did not seem to differentiate between the rate of absorption of ammonia and the rate of conversion of that ammonia to NO3. By inference we assume the limiting rate is absorption, but is that correct? Did you measure the rate of conversion?
  3. Were any temperature measurements made in the NU? Was it heated, cooled? Outdoors in the desert?
  4. A sanity check on the numbers in Table 3 says the apparatus should have converted about 115g of ammonia into 560g of calcium nitrate per day. Does that sound right?
-Jeff Evarts

Update: 18 hours later, Professor Gross has replied! Considering the time differential between here and Israel, that is incredibly fast. There is much detail in his reply, and I thank him kindly. When I find out what data is protected and what is not, I shall update this page. In the meantime: Read the paper!

Tuesday, August 27, 2013

Commercial compost: low nitrate levels. Experiments in holding pattern.

After the < 5mg/L reading I got from an earlier test, I ran the reference test, which ran correctly. Not that that's much more than a sanity check.

I wondered if I might have the wrong thing in the bag.

A first-level Agromin support person gave me values of nitrate as 2-8.6 milligrams per kilo dry weight of EcoScraps compost mix. That's less than 1/1000 of what I expected! I asked for someone else to call me back. No call so far today.

Further data from EcoScraps directly shows 0.001% dry weight as nitrates. So a kilogram of dry compost (is there such a thing?) would still contain on the order of 10mg of nitrate... right along with the Agromin folks and my tests.

It would appear that this compost is not suitable for LaConte style recoveries.

I now have the name of someone else to contact who may have more  comprehensive information on the subject of compost nitrate composition. I will call him tomorrow.

Compost experiments 2 and 3 halted for now.

Nitrates from commercial compost 3

I bought more equipment. This is a weakness. I must resist. I have two scales and a nitrate/nitrite test kit. I am continuing the previous experiment while moving on with this one.


  • Leaching may extract more (or less) nitrate over time.
    Check at 1 and 24 hours.
  • According to the literature, the evaporite is going to be a mix of [Na,K,Ca,Mg][CO3,NO2] with either the Ca or the CO3 at zero. Fe and Cl may be present as well.
    We will presume it is the CO3 species that is absent.
  • Potassium carbonate has the highest molecular weight of the various components of potash: 138g/mol.
  • Calcium Nitrate has the highest molecular weight of the various potential components of raw saltpeter: 236g/mol.
  • Suppose we have N grams of a CaCO3 precipitate. To calculate the amount of potash required to provide that much carbonate, divide by the molar mass of CaCO3 (100g) and multiply by the molar mass of potassium carbonate (138g) for a net mass multiplier of 1.38.
    1.38 times the Mass(CaCO3) is the max Mass(potash) to be used.
  • Suppose we have N grams of a Ca(NO3)2.4H2O evaporite. The mass divided by 236g is the number of moles of calcium nitrate. Calcium nitrate mixed 1:1 molar with potash results in 1 mole of calcium carbonate and 2 moles of alkaline nitrate. 138/236 =  0.58, thus:
    0.58 times the Mass(Ca(NO3)2) is the max Mass(potash) to be used.


    Part 1, 1 hour

  1. Place 1kg of compost in a stainless pot
  2. Add 2 liters of distilled water
    Checked: Total mass: 3kg 
  3. Let stand for 1 hour
  4. Filter (seive and paper towels, as above)
  5. Measure 1 liter of fluid
  6. Get mass of solution to estimate dissolved salts, and verify by checking weight of remainder of fluid and soil
    1003g (about 3g, estimate 6g in 1kg of compost)
    Remainder: 1997g
  7. Perform Nitrate test
    Nitrates: < 5mg/L (Well THAT sucks. Maybe it's wrong?)
  8. Return the fluid to the mass

    Part 2, 24 hours

  9. Let stand for 23 hours
  10. Repeat mass measurements

  11. Test for nitrate
  12. Was it worth waiting the 23 hours

    Part 3, Analysis

  13. Extract all the solution
  14. Filter the solution
  15. Evaporate with minimal heat
  16. Weigh evaporite
  17. Calculate the maximum potash required:
    0.58 * mass(evaporite):
  18. Gather the potash
  19. Dissolve the evaporite in a minimum of distilled water
  20. Divide the solution into two halves (S1 and S2)
  21. Divide the potash into two halves (P1 and P2)
  22. Add one tenth of P1 to S1
  23. Observe a precipitate (hopefully)
  24. Add more of P1 to S1 very slowly until no more precipitate is formed
  25. Weigh the dry remainder of P1
  26. Dry and weigh the precipitate from S1
    S1 Precipitate: 
  27. Recalculate the maximum potash required:
    1.38 * mass(precipitate)
  28. If this new "maximum potash" value is lower than the mass of P2, reduce the mass of P2 to the lower maximum.
  29. Add  the (possibly reduced amount of) P2 to S2
    Hopefully this achieves a zero value for both calcium and carbonate, leaving only nitrates in the wake
  30. Dry and weigh the precipitate from S2
    S2 Precipitate
  31. Compare the masses of the precipitates. They should be equal.

The pictures here are very low res because my regular digital camera has been lost, and I am taking stills with a videocamera instead. :P

Nitrates from commercial compost 2

Ala laConte, I try to get the nitrates to effloresce.

General Process

  1. Place 2 gallons (compacted) of compost in a 5 gal painter's bucket
  2. Add 1 gallon of distilled water
  3. Let stand in warm dry conditions
  4. Add more water
  5. Repeat steps 3 and 4
  6. Observe (or not) efflorescence

Actual process

24-Aug-2013: Steps 1-4 complete
27-Aug-2013: After three warm dry days, the compacted soil was still damp-verging-on-wet. I roughed the surface up to give more surface area for evaporation.

Tuesday, August 13, 2013

Nitrates from commercial compost 1


  1. Place 2 liters (uncompacted) of compost in a stainless steel vessel
  2. Add 1 gallon of distilled water.
  3. Wait an hour
  4. Filter the solution through metal sieves until all the large particles were removed.
  5. Pour it through paper towels (poor man's filter paper for large quantity jobs)

A not-very-clear solution remained. It looked a lot like a cross between tea and black coffee. The humus is composted from local waste vegetable material, presumably including things like coffee grounds, tea leaves, and tree bark, all of which could give a soluble brown tincture.

I elected to try and precipitate it out using a base (assuming tannic acid and its ilk were the colorants) so I tried chalk, then sodium hydroxide. Neither changed the color significantly.


Given a dark and now contaminated sample, I tossed it down the drain.

Sunday, August 11, 2013

Nitrates from commercial compost

This pursuit of nitrates has led me up several blind alleys, but they are an essential material for a variety of other early chemistry experiments. I really don't want to try the Chamber Process without at least some nitrate catalyst. I am torn.

The core problem


Modern industrial production of nitrates starts with nitric acid.

Nitric acid is produced from ammonia through the high pressure high speed platinum-catalyzed Ostwald Process.

Modern production of ammonia starts with high pressure high speed osmium catalyzed fusing of hydrogen and nitrogen: the Haber Process.
Obtaining nitrates is trivial in the modern world, and very complicated in a primitive environment

It would be easy to buy a cold pack or some fertilizer with ammonium nitrate in it, dissolve it, mix in some potash, et voilà! Saltpeter! Likewise neutralizing nitric acid with lye. But the thing is, there is essentially no natural source of ammonium nitrate or nitric acid and this is supposed to be a primitive chemistry blog.

As usual, space and time are the limiting inputs. If I had a large yard and a twelve to eighteen month timeframe, I could do all this "the right way" and not need to shortcut the system. I was pondering actually switching from renting an apartment to renting a house with a yard when something strange happened: I had an idea.

Someone else do the primitive "hard part"

There are various estimates of nitrate per ton of compost, but a consensus figure seems to hover around 1%. Thus 1kg of compost might contain 10g of nitrates.

This being southern California, there are a lot of community based composting services, because only the very rich can know that everything should be totally natural and completely free. :)

Simply buying a bag of "certified organic compost" and leaching it for nitrates would confirm whether or not the basic process worked like all the old texts say it does. So long as there were no high tech steps taken in the composting process and no external additives (neither likely in "organic" compost) it should be valid. There are even a couple of local places I could visit and see what actually went into producing the compost.

After a phone call to Agromin to make sure I was buying 100% unadulterated compost, I purchased their (rebranded) EcoScraps compost at a local hardware store.

Friday, August 9, 2013

Aerobic Vegetable Composting 1

After the disheartening math on nitrate production from liquid mammal waste, I decided to do a regular compost based on food scraps.  Whether this makes sense or not, I avoided garden clippings in this run because the measured goal is nitrate production. Any fertilizer remaining on the garden clippings would skew the results, showing a false success.

With that in mind, I am composting things that humans would eat, not simply vegetation. I expect I'll do a vegetation one as well, and perhaps both varieties supplemented with other materials, but for now I'm just taking the simple route.

Tools and Materials

Organic matter

I got the material from several local chain restaurants. I walked in, asked to speak with the manager, and asked if I could get a day's worth of produce scraps from their counter/prep area. Some did prep in the morning, and asked me to come back the next day. Others gathered their scraps all day and asked if I could come back later in the evening. Everyone was quite willing to help.

Here's what I ended up with:
  • Lettuce
  • Mix of lettuce & other vegetable matter
  • Meat scraps

The Composter

I just used a rolling trash bin I bought at the hardware store. I cut holes in the sides to allow aeration. I considered buying a "real" composter with a horizontally mounted cylindrical drum and a crank on the side, but for my first run I figured something less sophisticated would do. The bottom of the bin was watertight, to prevent solubles from escaping during the composting process.


The pile

Lettuce, cabbage, tomato, and other vegetable scraps have a C:N of about 12, so in order to get out to 20 or 25, I needed some carbon added. I bought a bale of straw from a local pet supply, weighed out Nkg and added it in in layers with the vegetable matter. This was a single-batch process. Everything was added at the same time.

The Weather

August in southern California is sunny, not particularly humid nor arid, and stayed in the 70s and 80s for the entire period.


Catastrophic failure, experiment terminated early. Apparently there was too much animal protein in the mix. By day six the rotting smell was overwhelming and I terminated it. I shall fall back and consider other alternatives, certainly including no animal matter in the next incarnation.

Monday, May 20, 2013

Paper 1

I have only a couple days before I leave on my trip, and I wanted to get something else done before I left, so a quick attempt at paper seemed reasonable. This may seem more craft than chemistry, but filter paper is important later on, so I'm including it here.

Raw materials: Dry grass, Potash, Water
Tools: A boiling pot, heat, a screen 

So here's the dry grass. It's really dry. It's been sitting in a box for weeks or longer, waiting for a project to come along. Originally it was going to be compost carbon, then weaving material, but finally it has become paper pulp fiber.
1 meter stalks of dry California grass

Step 1: Remove the nodes

I am not really sure why this is necessary, but all the small-scale references insist on it. I expect that if you're doing large-scale crushing or boiling the nodes break down by themselves, but on this scale it's worth doing the pruning.

Break the grass up into lengths with no "inter-segment nodes". That basically means break off the little hard parts where branches or leaves come out. Here is a piece of grass with two nodes circled
Grass with nodes circled
And break out the nodes completely, leaving just the stem bit
Grass stems

I am very slow, so after 50 minutes, I had a single thick handful, which I deemed a half liter or so.
A handful (~500ml) of straight grass stems

Step 2: Prep the Alkali

50ml Potash
WARNING: Do not use aluminum containers when working with alkali. Hot alkali, under the right conditions, can burn right through aluminum. When combined with boiling water, flames, and caustic solutions, this can be bad. Use glass, ceramic, or stainless steel containers.

I made a solution of 50ml of loose potash in 1 gal of water.

Step 3: Boil

The handful above contains more than a little woody stem (not wanted) as well as dirt, dust, and other detritus we want to get rid of. Boiling in alkali will separate all of these things for us as well as preparing the fibers themselves. If we were going to bleach the paper, this is the point where we'd do it. I didn't have the materials, so I skipped that step and just did the boiling.

I had the stems in the alkali while it came to a boil. After about 30 minutes of boiling, the scent of the steam changed from grassy to distinctly sweet. I held it at a boil for 60 minutes total, replacing the water as it boiled away. After that hour I took it off the fire, poured off the alkali and replaced it with fresh water.

Step 4: Rinse and Crush

This is pretty straightforward. I'm trying to separate the fibers from the rest of the stuff without making them too short.  I used a round wood stick against a flat wood surface, and the stems split and mashed immediately. Even though the stems were still rigid, the fibers themselves were extremely pliable and soft. The integrity of the stems as a whole was entirely an artifact of their geometry as a tube. During the rolling, some individual fibers got caught on the rolling stick and wound themselves up along it providing a very nice yarn which could be removed with a fingernail. The average fiber length at this point was quite long: over 8 cm.

Step 4a: The plan changes

The length of the fibers and the fact that they weren't crosslinking (they were staying parallel) gave me pause. I took the stems out and they bent and flattened easily, but the individual fibers stayed attached to their bretheren on the stem until something else snagged them.

I decided to alter the experiment mid course: I cut maybe half of the fibers to a length of about 3 cm using a knife and reboiled them in plain water, hoping that this would separate them and let them entangle/mat/felt more.
Shorter fibers boiling

Still not convinced

I took handfuls of the fibers and crushed them between two rocks, hoping to see something that looked like paper. Either this is going to take much longer than I expected (multiple hours) or the fibers are way too long. Perhaps more research is in order.

Tuesday, April 30, 2013

More saltpeter math - I am enlightened


Nitrates are enormously useful compounds, and this blog is about simple chemistry, so investigating simple methods of producing them are extremely relevant.


FIRST: Despite far too many bad internet references about making gunpowder out of urine, I have finally figured out why nobody gives instructions on how to do it. It is, for the most part, impractical.

SECOND: If what you're looking for is soluble nitrates, it's far easier to use "normal" composting materials like grass clippings and animal products than to try to leverage the urea in urine directly.

The investigation

After doing the math on the saltpeter yield and after a lot more research on the composting process, I have decided to take another whack at figuring out what it would take.

Target values

Ideal hot, nitrifying composting seems to occur near a C:N ratio of 25 and a moisture content of 40-60%. If there were nothing in the mass that wasn't nitrogen, carbon, or water, the ratios might look like: 40% water, 57.7% carbon, 2.3% nitrogen.

Raw Materials

To produce 1 kg of soluble nitrates, we need 140g of nitrogen. Targeting a C:N of 25, we need 3.5kg (25 x 140g) of carbon. Since straw and sawdust are still 20% moisture, we would need 4.375kg of that material to provide the right amount of carbon to balance out the nitrogen. To get 140g of nitrogen from urea, we need  32L of urine, which is essentially 100% water.

MaterialUrineStraw or

That would leave a moisture content of 90%. (32875g water vs 36515g total mass)


The light has come on. Given the urea content of 32L of urine, we only need 3.5kg of carbon to get the ratio right, but the water content is beyond all reason. That's probably why no one documents urine as anything other than a "de minimus additive".

Forcing the issue

Presuming the 32L could be reduced (boiled down?) to 1.625L (20-to-1 reduction) without loss of nitrogen, the numbers would add up more like
MaterialUrineStraw or

Which gives a moisture content of 40%. (2500g water vs 6140g total mass) Close enough.

So if the presumption is valid and you had to do it this way, you'd do something like:

  1. Reduce volume of urine to 5% original
  2. Add 2.3-3 times (by weight) straw or sawdust
  3. Mix and compost it

Nota Bene

Most of the "municipal water purification" references on the web (which also deal with nitrifying bacteria) have an end goal of anaerobic denitrification so the organic nitrogen is ultimately expelled as inert nitrogen gas. In this case, the high water content is no problem.

More practically

Follow the instructions from numerous sources which use fruit, vegetable, and fresh green plant matter. It produces the same nitrates, but doesn't require boiling urine.


Saturday, April 27, 2013

Acetone 1 (honey + chalk = acetone)

My longest chain to date:
  • Honey + Water + Yeast = Mead
  • Mead + Acetobacter = Vinegar
  • Vinegar + Chalk = Calcium Acetate
  • Dry distilling Calcium Acetate = Acetone
Acetone could be used to thin or strip paints, but I think the most likely use is as a recoverable solvent to extract oils from seeds. That would indeed be a labor boon.

  1. My original vinegar was made from mead, and thus contained a variety of compounds beyond simple acetic acid. I distilled it, and got a very clear product.
  2. It takes a surprisingly large amount of chalk to slake a relatively small amount of vinegar.
  3. The drying step is by far the longest part. I used a glass pie pan in a 200ºF oven. It took hours.
  1. Add chalk to vinegar until fizzing stops
  2. Add 10% more chalk than you have already added
  3. Add 100% more water by volume
  4. Filter the mixture to remove undissolved chalk, leaving a calcium acetate solution
  5. Place solution in a shallow bowl and apply gentle heat. (Over 160ºC would break down the acetate)
  6. Collect the calcium acetate
  7. Dry distill the calcium acetate producing acetone.

  • The calcium acetate came out a little dusky rather than totally white.
  • The distilled acetone came out light brown, but smell and application to styrofoam confirm acetone was present
  • Much of the solid remained unchanged

Acetone is a List II Substance

Tuesday, April 23, 2013

Saltpeter math

Nitrogen: The math

From Wikipedia
  • Grams of urea in a liter of urine: 9.3
  • Molar mass of urea: 60g
  • Molar mass of potassium nitrate: 101g
Break out the Unit Factor Analysis manual...

So to get 1kg of Potassium Nitrate, you would need about 32L of feedstock.

Wednesday, April 17, 2013

Glycerine 2, Soap 1

New attempt:
  • 380g tallow
  • 5 oz water
  • 86g store bought lye (WAY too much due to miscalculation)
  1. added the lye to the water and let it cool.
  2. melted the fat completely and let it cool for a minute or two
  3. combined the two and mixed lightly
  4. poured into a glass container and set aside to cool overnight.
Result: still an unseparated emulsion in the morning.

tallow on a scale - 380g
Tallow on the scale
cloudy solution of lye and water in a beakerPartially melted tallow in a potUnseparated
Lye and Water MixtureMelting before adding lyeUnseparated result
After 24 hours it was still pretty much a homogeneous gel, so I "remade" it:
  1. melted it over a stove
  2. added a cup of water (to aid in melting)
  3. added a cup of vegetable oil (to balance the excess lye)
  4. left to cool in the metal pot I did the melting in
Result: Really granular/void-filled soap, but definitely soap.

I also collected about a cup of water and a couple ml of cloudy glycerin

The soap was still really granular, and when I squeezed it I got a lot more glycerin. So I divided it into three balls and wrapped them in cheesecloth, then pressed them. This produced dryer soap and more glycerin, but not much more water.

Next note: Decanting two separated liquids is hard without the right equipment. I think that if I were doing this at scale I'd probably find it useful to make some specialized equipment

Day 6: The balls of soap are still in their cloth and still very slick. I think they're still exuding a bit of glycerin. But they do work as soap.

Day 20: The soap is now hard enough to be considered ready

Lye is hard to find these days. Went to 2 hardware stores, a supermarket and 2 drugstores. No dice. Ordered it from Amazon instead. Easy.

Wednesday, January 23, 2013

Nitrogen from composting

Posted nitrogen-fixing question to four composting forums:
But no particularly applicable experience/data. It seems like I'm asking people about the right problem at the wrong scale. I shall look elsewhere.