people often quote the j-300 publication,
unfortunately, it was publshed in 1999,
and in 2005 kodak has changed their tune ...

in a more recent publication " Darkroom Design for Amateur Photographers"
they specifically say to adhere to local regulations ..
http://www.kodak.com/global/en/profe...bs/ak3/ak3.pdf

on the bottom of page 7

"• Properly dispose of photographic processing chemicals
in accordance with local sewer discharge regulations.
Kodak does not recommend the use of septic systems
for disposal of photographic processing chemicals"