Swiss water treatment to use PAC/UF combination

Wabag Water Technology has announced two water-treatment contracts in Switzerland based on ultrafiltration (UF) and worth around € 6 million which were won by the company at the end of 2012.

In November 2012, WABAG received an order from Muttenz municipality for a new drinking water treatment plant employing advanced oxidation, adsorption and membrane filtration in order to clean the local groundwater, which is generally subject to organic trace substances and occasionally impacted by Rhine filtrate.

Highly resistant pollutant compounds will be broken up by ozone and hydrogen peroxide. In the next phase, powdered active carbon (PAC) will absorb the residual substances and finally UF will be employed to filter out the activated carbon in combination with the adsorbed contaminants.

This combination ensures that micro-pollutants, which are otherwise difficult to degrade, can be safely removed or reduced as has already been confirmed by operational results from a pilot plant at the location.

Muttenz is not only the first plant in Switzerland to employ continuous PAC dosing on UF membranes, but probably also the first in Europe to be equipped with this process technology. The plant will clean 17,500 m³/d of groundwater and commissioning is scheduled to commence in December 2014.

Heavy rain at the Wahlen waterworks results in sharp increases in both the turbidity and the bacteriological content of the karstic well water, and this necessitates a switch to drinking water from neighbouring districts. Accordingly, the local authority sought a suitable concept that would allow the continuous employment of the spring water throughout the year.

Wabag Switzerland convinced the client to use a first-class solution for the treatment of the karstic well water, and the waterworks is to be expanded to include a compact UF system with a capacity of 460 m³/d. The design with submerged membranes will facilitate economically advantageous integration into the existing building.

Wabag was commissioned as the general contractor. The work will take place during normal operation and is starting in February 2013. Following a 5-month project period, the membrane filtration is scheduled to become operational in June 2013.