In general, solid wastes from pulp production and paper
mill operations are humid and contain some organic compounds
in the form of wood or recycled paper fibres, chlorinated
organic compounds and pathogens, significant
amounts of ash and trace quantities of heavy metals.
Whereas the solid waste composition from pulp and
paper mills is known and constant, as a result of the current,
highly controlled production processes, sludge compositions,
on the other hand, vary widely throughout the industry
and are dependent on the type of operations carried out
at the mill. The wastes can be reused and valorised in a safe
and environmental way, so landfill is strongly being reduced
as their final destination. In fact, in countries such as Germany,
Spain and The Netherlands, certain waste streams
cannot be disposed at landfill sites. In addition, current legislation
and increased taxes have resulted in research on
non-conventional methods for the management or new uses