Implementation of the Water Framework Directive at Wastewater Treatment Plants in The Netherlands
Wiegant, W.1, van Betuw, W.1, Rijs, G.2, 1Royal Haskoning, 2 De Waterdienst, The Netherlands
(free)
The Water Framework Directive (WFD) quite often implies additional treatment of the effluent
from wastewater treatment plants (WWTPs). In The Netherlands, initial calculations demonstrated
costs of €3 to €25. PE-1.y-1 for measures ranging from achieving EU-standards for all WWTPs to
removing of priority components. For the most ambitious scenarios, this implies an approximate
doubling of wastewater treatment costs.
Today, ambitions have become more cost-oriented. The primary goal of most WFD measures is
achieving so-called maximum allowable risk levels for nitrogen (N) and phosphorus (P), mostly
translated into effluent concentrations of 2.2 mg/l for total N and 0.15 mg/l for total P. These two
components are considered the most responsible for the ecological quality of the surface waters.
Sand filtration, with chemical dosing for P removal and sometimes addition of methanol or acetate
for nitrate removal, is currently considered the most cost-effective technique for additional
treatment. Full-scale plants are already operational and this paper highlights some practical
results. Some attention is also be paid to alternative techniques, such as Fuzzy Filters, and also
to carbon filtration as the most logical next treatment step for removal of substances such as
hormones, medicines, herbicides and pesticides.
KEY WORDS
Carbon filter, Fuzzy Filter, Netherlands, Sand filtration, WFD
