Colston Robert E, Nair Ajay, Vale Peter, Hassard Francis, Stephenson Tom, Soares Ana
Cranfield Water Science Institute, Cranfield University, College Road, Cranfield MK43 0AL, UK.
Microvi Biotech, 26229 Eden Landing Rd, Hayward, California 94545, United States.
ACS Sustain Resour Manag. 2024 Sep 13;1(9):1906-1918. doi: 10.1021/acssusresmgt.4c00025. eCollection 2024 Sep 26.
Harvesting nutrients from waste presents a promising initiative to advance and deliver the circular economy in the water sector while mitigating local shortages of mineral fertilizers worldwide. Urine, a small fraction of municipal wastewater, holds substantial amounts of nitrogen, orthophosphate (PO-P), and chemical oxygen demand (COD). Separating urine aids targeted nutrient recovery, emissions reduction, and releasing capacity in wastewater treatment plants and taps into overlooked vital nutrients like magnesium (Mg) and potassium (K), essential for plant growth. The ability of selected microorganisms (, and ) to remove and recover nutrients from fresh urine through bio-mineral formation of struvite was investigated. The selected microorganisms outcompeted native microbes in open-culture fresh urine, and intact cell counts were 1.3 to 2.3 times larger than in noninoculated controls. PO-P removal reached 50% after 4 days of incubation and 96% when urine was supplemented with Mg. Additionally, soluble COD was reduced by 60%; urea hydrolysis was only < 3% in controls, but it reached 35% in inoculated urine after 10 days. The dominant morphology of recovered precipitates was euhedral and prismatic, identified using energy dispersive spectroscopy and X-ray diffraction as struvite (i.e., bio-struvite), but K was also present at 5%. Up to 1 g bio-struvite/L urine was recovered. These results demonstrate the ability of bio-mineral producing microorganisms to successfully grow in urine and recover nutrients such as bio-struvite, that could potentially be used as sustainable fertilizers or chemicals.
从废物中获取养分是一项很有前景的举措，有助于推动和实现水行业的循环经济，同时缓解全球范围内矿物肥料的局部短缺问题。尿液作为城市废水中的一小部分，含有大量的氮、正磷酸盐（PO-P）和化学需氧量（COD）。分离尿液有助于在废水处理厂实现有针对性的养分回收、减少排放和释放容量，还能获取被忽视的重要养分，如对植物生长至关重要的镁（Mg）和钾（K）。研究了选定的微生物（ 、 ）通过鸟粪石的生物矿化作用从新鲜尿液中去除和回收养分的能力。在开放培养的新鲜尿液中，选定的微生物比本地微生物更具竞争力，完整细胞计数比未接种的对照高1.3至2.3倍。培养4天后，PO-P去除率达到50%，添加镁时去除率达到96%。此外，可溶性COD降低了60%；对照中尿素水解率仅<3%，但接种尿液10天后水解率达到35%。回收沉淀物的主要形态为自形和棱柱形，通过能量色散光谱和X射线衍射鉴定为鸟粪石（即生物鸟粪石），但钾的含量也为5%。每升尿液最多可回收1克生物鸟粪石。这些结果表明，产生生物矿物的微生物能够在尿液中成功生长并回收生物鸟粪石等养分，这些养分有可能用作可持续肥料或化学品。
