Current scenario and challenges in recycling of human urine generated at source in rail coaches as resource

The current scenario of human urine being directly discharged into the environment without recycling, despite being an economical source of fertilizer. Train coaches are the major source of large-scale urine waste generation. Adopting a circular economy creates significant synergies toward usages of water generated after nutrient recovery from urine. Some advanced decentralized treatment systems, such as electrochemical, bioelectrical, or reverse osmosis, would be useful to treat and recover nutrients from urine waste/wastewater. The laborious and costly affair of removing nutrients like N, P, and K from human urine needed a sustainable solution. These recovered nutrients can be reused as fertilizers in irrigation and, indirectly, in large-scale biodiesel production by being used in microalgae cultivation. However, the potential of reusing human urine waste is yet to be explored commercially. Additionally, artificial intelligence may be explored with sustainable approaches for urine separation and recycling soon.