P removal from surface water in Belgium at a water production center of De Watergroep

23 October 2019 - Published by Charlotte Boeckaert
Belgian drinking water utility De Watergroep tested together with research institute VITO a P removal system in a pilot installation of the drinking water production center De Blankaart. In the latter, surface water is being treated to high drinking water standards. Since a couple of years this production center has to cope more and more with the consequences of eutrophication caused by nutrient input from the surrounding area, causing algae blooms between May and October.

Granulated sorbents from Al

VITO has produced a granulated sorbent from aluminum sludge, which is a by-product from the drinking water treatment process. At De Watergroep, the material was used in a downflow sorption set-up to treat 200 l/h of surface water, with a contact time of 10 minutes. To avoid clogging a back-washing regime was installed. Samples of the raw water going to the filter as well as samples of the filter outlet (taken automatically on a daily basis) were analyzed in the lab for phosphorous concentration.



In the first days of testing, removal yields of > 85% of ortho-phosphate (concentration in untreated water: 1.4 mg PO4-P/l) were obtained (figure above). In the following months, removal yields dropped due to lower phosphate concentrations in the raw water and lower water temperatures. However, the ortho-phosphate concentrations of the treated water were generally kept < 0.2 mg PO4-P/l. Furthermore, it was proven that after a “resting period” (a period without water flow) of a few days, the removal yield of the column increased again.

The sorption column is still running with the original sorbent material, while a second column is filled with new material (figure below).


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