Hi Aiden. Interesting that ...

Hi Aiden. Interesting that you get nitrate in urine. Fresh urine typically contains nitrogen in the form of urea (organic form nitrogen). When fresh urine is exposed to non sterile environment (such as sewer systems) the urea is converted to ammonia by bacterial urease. During this transformation pH of the urine changes from approximately 6 to 9 -9.2(due to the formation of ammonia an some other weak acid -base reactions). In order for nitrate to be present in urine there has to be an aerobic period during which ammonia is converted to nitrite an then nitrate (nitrification). Even then very liittle nitrate produced as nitrite oxidisers are inhibited by ammonia, its own substrate and the high salinity of the urine. Does the urine-containing wastewater get oxygenated somewhere along the line? Could you perhaps produce a schematic diagram of the wastetwater system. If there is indeed nitrate in the wastewater, all you have to do is denitrify it. For that you will require some form of organic carbon (readily biodegradable) as energy source for the heterotrophic organisms that facilitate denitrification (if the organic carbon in the urine has been depleted).