Urine is only sterile if 1) you don’t have a UTI, and 2) it’s collected sterilely. The tissue surrounding the urethral meatus often has bacterial colonies on the skin. So antiseptic would have to be used to clean the skin, and the urine would have to collected sterilely into a sterile container. Otherwise allowing urine to “age” is likely to result in bacterial growth. Regardless, bacteria still isn’t the biggest issue with drinking urine. You have to consider that this is what your kidneys excreted as waste, so putting it back through your renal system isn’t going to do any favors to your kidneys. Theoretically the same could be said for the liver if you are spilling bilirubin.