Reduced biodegradable matter increases the relative
proportions of HHW (and other waste types) in MSW. Increased
recycling rates for paper, glass etc., contributing >40% to MSW, will
boost the HHW proportion further. Leachate from existing and new
landfills will be expected to be very different to leachate from older/
closed sites due to changes in the composition of landfilled waste.
The consequences for the hazardous component of MSW require
further evaluation, although a decline in organic matter can be
expected to result in leachates containing predominantly inorganic
ions. The impact on the sorption of XOCs and heavy metal attenu-
ation may be beneficial, reducing the mobility of hazardous species.
Changes to leachate treatment techniques will be necessitated and
the long-term management of landfills adjusted.