In the experiments, the rate of ammonia volatilization was greater than the rate of water evaporation in the first period
So I previously cited science showing that adding the urine back into the previously separated out diversion toilet then sanitizes the waste better for composting.
So the issue is that the ammonia kills off the aerobic bacteria that otherwise composts the humanure. So it's not just the amount of urine in ratio to carbon but the study shows that "sawdust" composting with the mix of urine and humanure actually evaporates nitrogen back into the air via the "ammona volatilization."
So even though the urine will kill off contamination by the creation of ammonia - and also creating a strong odor - the sawdust compost method says with enough carbon coverage then there is no odor but they do NOT mention that the nitrogen (mainly in the urine) is now LOST to the air!! This contributes to global warming also.
Multivariate analysis showed that manure application within a year increased the odds of a Salmonella-positive field (odds ratio [OR], 16.7), while the presence of a buffer zone had a protective effect (OR, 0.1). Irrigation (within 3 days of sample collection) (OR, 6.0), reported wildlife observation (within 3 days of sample collection) (OR, 6.1), and soil cultivation (within 7 days of sample collection) (OR, 2.9) all increased the likelihood of an L. monocytogenes-positive field.
Risk Factors Associated with Salmonella and Listeria monocytogenes Contamination of Produce Fields
So obviously the humanure needs to be composted for two years still but the "yellow water" is sanitized on its own with much less ammonia production as lost nitrogen.
In other words it truly is best to keep the two separated.
In urine separating toilets (also known as no-mix toilets) (Fig. 9) urine is collected andSo that will be the way to go. Worms are actually invasive where I am at. So containing them in my compost bill will be good for the forest ecology also.
managed separately, typically with end use as a fertilizer. Urine separation in flushed toilets is now well accepted in some European countries (Lienert and Larsen, 2009). Urine separating composting
toilets (e.g. Seperatte toilets) and urine separating vermicomposting toilets (Hill and Baldwin, 2012) are also commercially available. Urine separation has the advantages of reducing unwanted odor and excess moisture in the compost pile. In addition, urine can be an effective fertilizer because of its high nutrient and low pathogen content. Humans release 7–10 times more nitrogen, 2–3 times more potassium, and 2–3 times more phosphorus in urine than in feces (Table 1). Urine separation combined with vermicomposting especially seems to hold good
promise. Lab studies simulating vermicomposting of feces resulted in highly mature compost with complete inactivation of total coliforms (Yadav et al., 2010). Recently Hill and Baldwin (2012) compared the field performance of urine separating vermicomposting toilets with combined collection composting toilets. Their results significantly favored the urine separating vermicomposting toilet,
which performed much better in mass reduction, pathogen destruction, compost quality, and operational cost.
citing:
Lienert, J., Larsen, T.A., 2009. High acceptance of urine source separation in seven
European countries: a review. Environ. Sci. Technol. 44, 556–566.
Finally it was evaluated how much nitrogen can be recovered in the urine diverting composting toilet system (UDCTS) and its result was compared to the recovery rate of nitrogen in conventional style in which faces and urine was treated in the sawdust matrix without separation.
https://www.jstage.jst.go.jp/article/proes1992/41/0/41_0_79/_article/-char/ja/
Maintaining pH in 6.7–9.0 range helps to control nitrogen losses by ammonia volatilization (Bernal et al., 2009). pH typically drops as the composting process progresses due to the breakdown of carbonaceous material to organic acidic intermediates by acid forming bacteria (de Bertoldi et al., 1983). The pH of the compost pile is observed to increase with increase in temperature (Epstein,1997;de Bertoldi et al., 1983).
https://www.jstage.jst.go.jp/article/proes1992/41/0/41_0_79/_article
Strange this is not cited.
https://sustainableklamath.org/articles/matlRscs/reviewOfCompostingToilets.pdf
Hotta and Funamizu (2007) note that 66% of fecal nitrogen decomposes to
ammonia whereas 34% remain as biologically inert type of nitrogen.
In other studies, nitrogen losses from 17% to 94% have been reported
in presence of sawdust as the bulk matrix (Bai and Wang,
2010; Wang and Wang, 2008; Zavala et al., 2005; Hotta et al.,
2007). In thermophilic conditions all nitrogen loss to ammonia
gas can be from inorganic nitrogen whereas the organic nitrogen
can be fully retained in the compost (Bai and Wang, 2010). This
is because ammonifying bacteria are mesophilic and their absence
in thermophilic conditions would hinder ammonification. In the
case of fecal carbon, approximately 80% of fecal carbon is mineralized
to CO2 (a greenhouse gas) whereas further 20% remains in the
composted material (Hotta and Funamizu, 2007). Loss of carbon
and nitrogen in gaseous emissions of CO2 and ammonia reduce
the amount of fertilizer nutrients available to fertilizers and therefore
the agronomic value of the compost.
OK so they cite it but kind of skew the results!
Finally approximately 60% of nitrogen from human excreta can be recovered as organic type that included with urea nitrogen in the UDCTS. When inorganic ammonia nitrogen could be counted into the recovered nitrogen, more than 90% of input nitrogen from human excreta might be recovered, while less than 5% of input nitrogen was estimated to recover in the conventional system.
So as far as retaining nitrogen for fertilizer then the urine diverting composting toilet system (that I already obtained at a high price) is the best proven system.
In order to minimize re-contamination of end-products with
pathogens from raw excrement, urine could be diverted reducing
leachate and/or end-product could be isolated from the collection
zone and stored. More rapid, consistent, and thorough pathogen
destruction could be accomplished by adding ash...
Source separating vermicomposting toilets (SSVCs) are an
alternative remote public toilet system commercially available in
Europe. By diverting urine directly to infiltration fields, nutrients in
urine are dispersed into active soil layers and the fertilization effect
of using urea as a sanitation agent is avoided. Vermicomposting of
urine diverted and un-amended fecal matter is thus enabled and
dramatically reduces O&M costs compared to current composting
(dry) toilet systems (Hill and Baldwin, 2012).
Hill, G.B., Henry, G.H.R. The application and performance of urine diversion to
minimize waste management costs associated with remote wilderness toilets.
International Journal of Wilderness Management, in press.
Hill, G.B., Baldwin, S.A., 2012. Vermicomposting toilets, an alternative to latrine
style microbial composting toilets, prove far superior in mass reduction,
pathogen destruction, compost quality, and operational cost. Waste Management.
http://dx.doi.org/10.1016/j.wasman.2012.04.023.
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