A waterless urinal at the metro stations is another facility that was added. In a first of its kind initiative, the Hyderabad Metro Rail and SGP waste water managers collaborated to convert urine into safe water.
This methodology not only helps converting urine to safe water, but also helps increase in the ground water levels as the treated water is directed to a soak pit through a channel. This water can also be used for plants as this does not emanate foul odor and works as good as normal water. The urine is collected in anaerobic digester, where anaerobic microbes degrade urine in
absence of air and reduce stickiness and TDS i.e. Total dissolved solids. Then by gravity urine enters to activated carbon filter followed by Biofilter.
The biofilter technology is based on eco technology principle. In this unit the microbial culture and media is led down in appropriate manner for drop to drop filtration of urine. The main principle of this system is symbiotic relationship between plants and microbes. The ammonical nitrogen from the system is broken down by microbial strain in which ammonia and nitrogen is separated.