Tattoo solidifier in shops

So basically the town I live is just recently started any regulations on tattoo shops, so the shop I am at is in the process of getting every thing up to proper regulation such as body artist license, setting up biowaste pick up and having separate rooms for each station. So it’s my understanding that liquid waste is to go into the sewage (down the sink) and we’re not able to have a sink in each station. So we’ve looked into liquid solidifiers but I’m just wondering if its necessary for biowaste or is the rinse cups being soaked up by paper towels is acceptable. If anybody knows what is the correct course of action for liquid waste.