Senior Consultant, Sweco Environment, Sweden

Speech Title: Swedish Experience and Excellence in Wastewater Treatment Mirrored Especially in Phosphorus Removal

Abstract: The water environment protection in Sweden has a more than 80 year history. The needed knowledge has by large been imported. Now, to some extent the development of phosphorus removal technology may be seen as Swedish contribution to an andvanced knowledge. This paper presents the development in Sweden, mainly a close to 50 year period. The initial effluent demands, a standard of < 0,5 mg P/l was the normally raised criteria, regardless of the magnitude of the discharge flow. The successive sharpening of the discharge levels have today resulted in typically a level of 0,2 to 0,3 mg P/l. As a matter of fact even levels of 0,1 to 0,15 mg P/l have been discussed.

The period has to a large extent demonstrated both improved technologies and also a far better efficiency with respect to the use of chemicals and energy. Some important points in this development may be seen as the understanding of the Oxygen Consumption Potential, the identified needs for an improved nitrogen removal. Lately has the problem of complex pollution agents and predominantly the remains of pharmaceutical agents. To illustrate the development during the period two examples are presented from the Swedish theatre.

The main conlusion in this paper is that the Swedish history on phosphorus removal illustrates empirical science in practice, including an never ending need for an open mind and a readiness to take revised and improved knowledge on board.