Fate of Nitrogen and Phosphorous in Source-Separated Urine
In this paper, we focus on the fate of nitrogen (N) and phosphorous (P) in source-separated urine. Fresh mixed urine of pH 6.7 was diluted with different factors and stored openly and closed respectively. With pH increasing concentration of total phosphate (TP), total nitrogen (TN), ammonia nitrogen(NH3-N) and dissolved phosphate(PO43-) were measured to understand the fate of N and P in urine. Because of volatilization and precipitation, concentration of NH4+-N and PO43- in the urine stored closed was higher than them of stored openly with the equal dilution. Under same storing conditions, the higher dilution factor, the higher concentration of NH4+-N. When stored openly the pH of the samples increasing due to urea-hydrolysis resulted in precipitation which consumed N and P, and could be promoted by dilution with tap water containing hardness ions. Because of a few of hardness ions in the urine and tap water, the amount of precipitations containing calcium, magnesium, N and P in the urine sludge of every sample were not high enough to be detected by XRD. Although more flushing water would caused more precipitation, which is also helpful for nutrient recycling, using of large deal of tap water is not economic and environmentally friendly.
Yanguo Shi and Jinlong Zuo
L. F. Dong et al., "Fate of Nitrogen and Phosphorous in Source-Separated Urine", Advanced Materials Research, Vols. 183-185, pp. 328-332, 2011