Operating a pilot-scale nitrification/distillation plant for complete nutrient recovery from urine

Abstract

Source-separated urine contains most of the excreted nutrients, which can be recovered by using nitrification to stabilize the urine before concentrating the nutrient solution with distillation. The aim of this study was to test this process combination at pilot scale. The nitrification process was efficient in a moving bed biofilm reactor with maximal rates of 930 mg N L−1 d−1. Rates decreased to 120 mg N L−1 d−1 after switching to more concentrated urine. At high nitrification rates (640 mg N L−1 d−1) and low total ammonia concentrations (1,790 mg NH4-N L−1 in influent) distillation caused the main primary energy demand of 71 W cap−1 (nitrification: 13 W cap−1) assuming a nitrogen production of 8.8 g N cap−1 d−1. Possible process failures include the accumulation of the nitrification intermediate nitrite and the selection of acid-tolerant ammonia-oxidizing bacteria. Especially during reactor start-up, the process must therefore be carefully supervised. The concentrate produced by the nitrification/distillation process is low in heavy metals, but high in nutrients, suggesting a good suitability as an integral fertilizer.

Extent computation under rank-deficient conditions

“…We demonstrate the developed method by means of data collected during a single cycle of an intermittent flow stirred-tank reactor for biological urine nitrification (Udert and Wächter, 2012;Fumasoli et al, 2016). This cycle starts with a short feeding of source-separated urine collected at Eawag with No-Mix toilets (Larsen et al, 2001).…”

Self-Powered Bioelectrochemical Nutrient Recovery for Fertilizer Generation from Human Urine

“…Several technologies have been proposed for nutrient recovery from urine, including struvite precipitation [10][11][12][13], ammonia stripping [14][15][16][17], stabilization + distillation [18][19][20], electrochemical concentration such as electrodialysis [21,22], and membrane distillation [23,24]. All these technologies require one or more of the following: high energy consumption, high chemical requirements, and/or control systems to ensure operability.…”

Simultaneous phosphorous and nitrogen recovery from source-separated urine: A novel application for fertiliser drawn forward osmosis

“…However, despite the high potential of the nitrification-distillation process, at present, its costly operation makes its applicability limited (Fumasoli et al 2016). Pressure-driven NF/RO are not often employed due to their unsatisfactory rejection of urea and ammonia (the most predominant compounds in human urine) as well as high capital and operational costs (Maurer et al 2006, Zhang et al 2014.…”