There is a post on this forum that is entitled What does urine mean? That would be a great post to read for answers to your questions about toxicity and waste in urine.....of which there are none.
My son's pediatrician was the first one to tell me that urine is sterile. My nude little one was standing waiting, too long, for the doctor to come in and do his part of the well exam. The diaperless little guy just let it flow right onto the floor of the examining room. LOL. The doctor finally walked in at that moment and calmly informed me not to worry, that urine is sterile. So when, years later, I started reading about UT, I was already aware of that. Lucky for me that I had a smaller hurdle to overcome.
Oh, and the more you use UT, the milder the taste is. You will learn which food are going to make it unpalatable to you the next day. you can choose to avoid them or just grin and bear it.