Bengaluru, Aug 28: Convinced about its medicil values, Indian scientists had taken a patent on cow urine in 2002. Now, researchers at the Intertiol Centre for Ecological Engineering of Kalyani University near Kolkata report that human urine can be used as safe fertiliser “after eight months of storage under closed conditions.” Urine contains the essential plant nutrients — nitrogen, phosphorus and potassium — besides some growth-promoting agents like amino acids, glucose and vitamins, says the report by Bara Bihari Ja and his colleagues published in the Indian Jourl of Experimental Biology.
On an average, each person excretes almost six kilos of pure plant nutrients via urine, says the report. “The amount of human urine generated daily in a highly-populated country like India can be an important resource if it is maged properly as liquid fertiliser.”
Ja’s team had been working for over a decade on the project to test human urine as a replacement for chemical fertiliser. “Earlier we have examined the fertiliser value of human urine for the production of fish food,” he said.
In recent years, human urine as liquid fertiliser is getting attention in Europe and in some Scandivian countries in view of the promotion of organic farming, says the report. The possible presence of disease-causing pathogens in urine had raised some questions. Though storage has been advocated by others for ictivation of bacteria in urine, there has been no study so far to examine this aspect under tropical conditions.
Ja says his latest study aimed at examining the pattern of changes in the counts of coliform bacteria as well as physico-chemical characteristics of human urine during different days of storage under closed conditions in order to identify the optimal storage period of human urine for use as safe fertiliser. The urine for the study was collected from students in the university.
According to the report, the study found that human urine during the storage period “undergoes microbiological and associated chemical changes and becomes highly alkaline”, resulting in death of pathogenic bacteria.
“We observed that after 253 days of storage under closed condition, the coliform counts were reduced significantly and remained within the safe limit,” the report said.
According to the author, human urine is cheaper and more environment-friendly because hazardous chemical compounds or heavy metals such as cadmium are generally absent or low in human urine compared to commercially available fertiliser. An added advantage is that its use would reduce eutrophication — the process where fertiliser washed off the land cause damaging blooms of plankton in rivers and lakes. “With the results of the present study, it may be concluded that human urine can be used as low-risk fertiliser after its storage for 253 days under prescribed conditions,” the report said. “Further research and extension activities of this work is necessary,” Ja added. “This can be done through NGOs, self-help groups, etc.” (IANS)