The operation of the Jänschwalde open-cast mine with the necessary drainage systems reduces groundwater levels in the region around the open-cast mine. When analyzing these influences, effects on the Pastlingsee could not be excluded. For this reason, upraised groundwater is injected into the Pastlingsee, which is approx. 10 hectares large and approx. 1 meter deep.
Since the phosphate content of the well water for the lake feed is very high at 500 µg/l to 600 µg/l, the water treatment plant for phosphorus elimination (PeliCon) was built for this purpose in 2020. The flotation plant is combined with the addition of flocculants in the inlet pipe, whereby the phosphorus is adsorptively bound to iron hydroxide.
In cooperation with scientific institutions, trials were run to demonstrate the separation performance of the selected PeliCon process in order to prove reliable compliance with the required limit values. Furthermore, the suitable products for the separation of total phosphorus and their consumption quantities were determined in the tests.
In addition, a rough estimate of the sludge quantities and their solids content was made.
Based on the preliminary tests, the flocculant and flocculation aid were selected and the required dosage determined so that a very high process stability can be achieved and the significantly reduced residual phosphorus content of ≤ 35 µg/l can be complied with by adding a 0.08 l/m³ FeCl3 dose.
