ABSTRACT
Summary Current sludge production and disposal information for Europe and North America is presented. It is predicted that future sludge production will likely increase with increasing sewered populations and improved wastewater treatment. Current sludge disposal practices in order of their importance are: Agricultural land including horticulture, gardens, etc. Other land, mostly landfills>>Incineration>Sea>Unspecified, including storage. This order is unlikely to change rapidly. A variety of novel sludge disposal strategies is considered including, e.g., earthworm conversion, use as an animal feed supplement, thermal conversion to liquid and solid fuels. Most are unlikely to account for large amounts of sludge in the future, however, thermal conversion to liquid and solid fuels appears promising and might largely replace incineration.
