The Utilization of Struvite Produced from Human Urine in Agriculture as a Natural Fertilizer: A Review

Abstract

Most of the nutrients in municipal wastewater originate from urine. Nevertheless, chemical fertilizers are commonly used in the agriculture instead of urine. There are some problems related to the direct utilization of urine, such as micropollutants present in urine, odour and storage of large volume of urine. In wastewater, phosphorus may contribute significantly to the pollution of the aquatic systems. Therefore, wastewater treatment techniques are mainly focusing on removing phosphorus. Phosphorus is collected in the sludge either by a chemical or by a biological process. With the growing concern of micropollutants present, which are in the sludge, the use of sludge in agriculture has been gradually decreasing. It means that the phosphorus content in sludge is not recycled efficiently whereas the use of limited mineral phosphorus resources is growing. To overcome these issues, urine could be collected separately and struvite could be produced. This may recover about 90 % of phosphate in urine. In this paper, the use of human urine and struvite as a fertilizer in the agriculture and the production of struvite is discussed. Results showed that the struvite could be an effective natural fertilizer.

Taking Container-Based Sanitation to Scale: Opportunities and Challenges

“…In places where water tables are high or infiltration is slow, there could be significant standing water and contamination issues. There has been substantial research by the VUNA project among others on urine resource recovery, but these technologies have not been integrated into CBS services (Simha and Ganesapillai, 2017;Hyun et al, 2019;Nagy et al, 2019) 12 . Applied research that achieves a value-add proposition for integrating urine and graywater solutions in CBS services is an area of great interest.…”

Life Cycle Assessment of Urine Diversion and Conversion to Fertilizer Products at the City Scale

“…101,102 The development of large-scale urine collection and processing systems is still at a conceptual stage. Research is ongoing to understand and address the many challenges of urine diversion, including economic, market and regulatory acceptance, 12,26,[105][106][107][108] potential user error, 26,109 risk aversion and lack of confidence in performance, 8,106,107 and lock-in to conventional systems. 107,110 Irrespective of the urine processing method considered, net benefits were observed for each scenario evaluated.…”

Size-dependent growth kinetics of struvite crystals in wastewater with calcium ions

“…Amorphous calcium phosphate ACP appeared in solid phase. The final product represents thus a mix of both these phosphates, what is not, however, essential drawback in practical application of such product in agriculture as a valuable mineral fertilizer slowly dosing its nutrient content [27,28].…”

“…Composition of impurities observed in liquid manure influenced also struvite crystal shape disadvantageously (compare Figure 1a and 1b). In general, quality of the product manufactured from liquid manure CLM should be regarded as unsatisfactory in respect to market demands [27,28]. Improvement of the product quality is, however, possible, among others, through elongation of residence time of struvite suspension in a crystallizer [15,16,24].…”