Ok, accepted. I seem to have missed out on this one on effective microorganisms:

forum.susana.org/forum/categories/214-va...l-sludge-includes-em

Quite interesting, but still controversial, I would say.

I guess we have to make a more clear separation between the original topic, e.g. smell suppression of more or less fresh urine, and various longer term treatment like fermentation or composting that are designed to retain nitrogen and thus also reduce the smell somewhat.

@HAPitot: we had a longer thread on Terra preta and EM1 fermentation before.

Lactobacteria have also been used by Ralf Otterpohl in his Terra Preta sanitation. Any opinion on that?

Hello sir,

Good to see your observation and its right. Adding the water leads to hydroylsis and produce stinky ammonia gas.

The smell can be controlled. There is a product called EM.1, japan origin contains three crucial microbes, namely Lactobacillus, yeast and Photosynthetic bacteria produce enzyme which act on the organic matter and start to eat to get energy.

Lactobacillus are best to control the urine stink, as they produce special enzyme called Amylase.

Calcium hydroxide is rather cheap - the 2013 price was about US$0.08 per kg. Enzymatic urea hydrolysis can be prevented by acid addition, the addition of urease inhibitors or by electrochemical treatment. Our paper gives some references for these techniques along with disadvantages. I don't think ozone will be able to stabilize fresh urine.

Sounds as though you've found the egg of Columbus in sanitation - at least for those who live in the temperature range of 14 - 40 degrees C!

How much would Ca(OH)2 cost, do you know? And do you also happen to know alternative processes of this kind? Ozone treatment? Reminds me that I once experimented with sulfuric acid to treat urine, but I can't really recommend it. Making it alkaline is probably a better idea since it also helps in most soils.

Cheers, H-A

Fortunately, the high pH inactivates viruses while higher temperatures (approx. 35°C) is effective for inactivating Ascaris. Our colleagues have investigated this in detail and they should be publishing their results in the next few months. In short, they have shown that the inactivation of viruses increased exponentially with a pH > 11.5 such that a 4 log inactivation could be obtained in minutes to hours. These experiments all involved urine contaminated with feces and known viruses. Our process of using calcium hydroxide ensures pH values higher than 11.5 are maintained thus providing stabilization and hygienization in a combined process. It's also important to note that this process prevents enzymatic urea hydrolysis and the subsequent strong ammonia smell but it doesn't remove organic odors. However, the organic odors are mild in comparison to the potential ammonia gas formation.

Interesting, indeed!

What about 'fast track hygienization'? With urine, odor control in one thing, the other critical issue is to get it hygienized a bit fast, especially if the urine is presumed to be contaminated by feces, i.e. faster than the recommended months-long storage time.

And could the two be possibly combined into one process?

Cheers, H-A

Hi everyone,

This is a very interesting discussion! We have recently published a paper that gives details on stabilising fresh urine by the addition of calcium hydroxide. Here is the link to the paper and it's open access: www.sciencedirect.com/science/article/pii/S0043135416301348

Let me know if you have any questions regarding this work.

Dyllon

Charcoal works wonderfully to control odor. Using Charcoal made from crop waste, which is adsorbing vs. absorbing (sawdust), saves space in the UDDT. Using the heat given off by pyrolysis to pasteurize feces, makes for a nice, ecological system. If product is used as fertilizer, it sequesters carbon in the ground instead of releasing CO2 into the atmosphere. If formed into charcoal briquettes, it helps save trees and lungs.

Interesting, but that seems to refer to longer term storage and/or composting where a large part of the Urea/ammonia has already been released to the atmosphere and the effects described only lower the release of the remaining -mostly organically bound- nitrogen during decomposition, or am I missing something?

Direct application of relatively large quantities of sawdust to fresh feces in the dry-toilet or composting toilet case will probably also absorb a lot of the free moisture and thus make it more difficult for the urease producing bacteria to thrive.

But I still don't think that applying saw-dust or wood chips to fresh urine will help much, unless it is being soaked up more or less completely.

Sawdust is acidic and thus can suppress ammonia production in stored manure and reduce nitrogen losses in composting.



DOES ADDING STRAW OR SAWDUST TO CATTLE EXCRETA REDUCE AMMONIA, NITROUS OXIDE AND METHANE EMISSIONS
DURING STORAGE? by Tony van der Weerden, Jiafa Luo, Moira Dexter and Martin Kear

www.massey.ac.nz/~flrc/workshops/13/Manu...nDerWeerden_2013.pdf


As the C:N ratio increases with addition of carbon rich materials, nitrogen losses in composting are decreased and that means both ammonia and nitrous oxide.



Effects of Straw, Sawdust and Sand Bedding on Dairy Manure Composting by Frederick C. Michel, Jr., Harold M. Keener, Jerome Rigot, Tom Wilkinson and John Pecchia, Department of Food, Agricultural, and Biological Engineering, Ohio Agricultural Research and Development Center, Ohio State University, Wooster, Ohio
www.cals.ncsu.edu/waste_mgt/natlcenter/sanantonio/Michel.pdf

Finally Joe Jenkins discovered empirically that fresh sawdust can suppress odour from excreta (urine and faeces mixed) such that he recommends sawdust toilets for indoor use followed by emptying into an outdoor compost. humanurehandbook.com/

Regards