ABSTRACT
In the netherlands, wastewater is treated in plants with the sole purpose of meeting the water standards specified by the Pollution of Surface Waters Act (see Chapters 1 and 11), which prohibits the discharge of polluting or harmful substances into surface waters without a license. As a consequence of this act, sewage treatment plants were built, mainly to reduce chemical oxygen demand (COD) and the amounts of phosphates and nitrogen present in wastewater. Since 1998, all water in Dutch sewage networks is treated, and almost all households have been connected to municipal sewage treatment (EEA 2005).
