My local water utility told me that treatment center process would remove the toxins so, if I desired, I could dump it down one of my sink drains. The last time I had enough coolant to actually bottle I did take it to my City's monthly household hazardous waste disposal event. This is a good reason not to change coolant more often than needed - the waste disposal issue. You can take used oil to a lot of places locally, but not other fluids.