•Compliance
to national and EU legislation (e.g. Urban Waste
Water Treatment Directive (UWWTD).
Challenges
•Tertiary treatment obligatory for discharge into
sensitive water bodies
•For large cities > 150,000 inhabitants
tertiary treatment is also obligatory
for discharge into normal waters
•Increase
in the quantities of sewage sludge
•Urban-to-rural
continuum
•Investment
and O&M costs
•Agriculture