The Thun region produces around 30 million litres of wastewater every day. Before it can be returned to the water cycle, it must be collected and cleaned. The ARA Thunersee and the sewer network of the 36 connected communities fulfil this task there. 95 % of the organic substances are decomposed, 75 % of the nitrogen and 95 % of the phosphorus are removed from the wastewater. SCHAUB Umwelttechnik GmbH has now also contributed to this impressive statistic, having designed a powdered activated carbon storage and dosing system for the ARA Thunersee, which was completed in 2016.
The activated carbon powder is stored and retrieved in the two silos, each with a capacity of 80m3.
The powdered activated carbon is subsequently metered gravimetrically by means of the fine metering devices. Each dosing unit has a capacity of 2 to 50 kg/h powder activated carbon.
In order to guarantee a constant water supply, a water dosing unit with flow meter and downstream control valve is installed for each line, so that a constant preset flow rate can always be regulated. Via the cross-full connection of the two PAC dosing lines, 5 different operating variants can be displayed.
These are shown in the following block diagram: