A laboratory scale activated sludge treatment system was developed for
the treatment of phenoxy herbicide chemicals and the associated chlor
ophenols in a toxic landfill leachate. A novel sludge recycle system w
as employed to ensure high specific activity of the return sludge. The
activated sludge treatment resulted in 99.5% removal of phenoxies and
chlorophenols and 84% TOC reduction for 10% influent leachate concent
rations. The corresponding toxicity reduction was 76%. An increase in
influent concentration resulted in a decline in activated sludge perfo
rmance.