In the Netherlands drinking water treatment practically always generates aquafer as a residual. By treating this material with acid, we intend to reproduce iron salts. The salts can then be reused as a flocculant in drinking water or wastewater treatment.
Reuse of iron salts
The abstraction and treatment of drinking water always involves the formation of aquafer (iron sludge), either through the aeration of ferrous groundwater, or through the addition of iron salts as a flocculant. By treating this iron sludge with acid, iron salts can again be made and then reused as a flocculant in wastewater or drinking water treatment processes. The material can therefore be reused and the resource loop closed.
Research into technical and economic feasibility
Attempts have been made in the recent past to reuse iron salts in this manner. To begin with, we will examine where to expect possible problems in the process, and how to solve them. These solutions will then be studied in lab experiments to see whether they work. Pilot tests will then be conducted at a drinking water company and a waterboard, to study whether this kind of reuse is in fact feasible and to determine its environmental benefits.
Circular process promotes sustainability
The use of flocculants accounts for a large part of the footprint of drinking water treatment. Moreover the drinking water companies are in search of application possibilities for the formed sludge. An exploratory LCA study has shown that making flocculants from aquafer and the reuse of these flocculants can significantly shrink this footprint. This study will examine whether this can be realised in practice.