Hello, my name is Dr. Kara and I have 20 years of experience as a veterinarian.
The white bits that you are seeing in this little ones urine can be mucous, or crystals in his urine and may indicate very concentrated urine.
Since he came to you as an orphan it is possible that he was a bit dehydrated and this is leftover material from being dehydrated.
It is possible that this may be related to a urinary tract infection, but those are unlikely at this age, and I would think that you would see other signs of illness such as a poor appetite or high fever.
I would just make sure that this little one is getting plenty of fluids and take a watch and see approach at this point. If this continues, even with making sure that it is getting plenty of fluids, then it is time for a veterinary examination.
Please let me know if you have any further questions.