removal of ethidium bromide - (Apr/10/2006 )

how do you dispose ethibro solution?
I always dilute 20 µl ethibro (10 mg/ml) in 400 ml water. this means, the concentration becomes 0.05 µg/ml ethibro solution (please correct me if im wrong).
do you use charcoal do filtration with it? and how much do you use?

thank you
audrey

hi i use columns from schleicher and scuell for liquid decontamination.
My university facilities deals with the solids contaminated with EtBr and i don't know how.