Using slag as sorbent to remove phosphorus from wastewater
Résumé
Considering the EU legislation on phosphorus rejected in the surrounding environment including for
wastewater treatment plant having a capacity less than 2000 People Equivalent (see Water Framework
Directive [2000/60/EEC]), it appears that using additional filter systems filled with reactive materials rep-
resents a valuable solution to remove phosphorus in small wastewater treatment plants such as sand fil-
ters, constructed wetlands or waste stabilization ponds. To answer this new need, SLASORB was
launched back in July 2009. The first part of the project was devoted to the selection of relevant slag in
Europe to enable the design and the use of slag into demonstration scale filter for treating phosphorus
from wastewater. The second part of the project was devoted to the design and construction of 2 demon-
stration scale filters and to see the technical feasibility of using slag for phosphorus removal in existing
wastewater treatment plants representative both of the French and German market. The third part of the
project was mainly focused on the economical feasibility of using slag filters for wastewater treatment. On
the one hand the potential of recycling slag saturated with P as fertilizer was studied, on the other the
commercial offer and both the market price and demands were studied. The main objective of each WPK
will be presented in this summary.
Despite a short project extension (the project ended up in Dec 2012 instead of July 2012) we can say that
the main objectives of SLASORB were reached: Slag have been shown to be a valuable reactive material
for P removal in Europe, technical and economical feasibilities have both been established, demonstration
scale systems were able to remove a significant amount of P without any environmental issues associated.