3. Material and methods
3.1. Tested waters
Experiments were carried out using groundwater
collected from two wells of Etna volcano
(“Well 1”, with a flow of 25 L/s and “Well 2”,
with a flow of 45 L/s) upwelling the water from a
depth of about 300–340 m below the ground surface.
These waters represent the drinking water
supply for several towns in the Mont Etna area.
Collected water samples were immediately transferred
to the laboratory and utilized for the tests
in order to avoid air-oxidation of manganese during
storage. Due to the different Mn concentration
in the water obtained from the two wells, tests
were conducted using mixed samples (based on
the upwelled flowrates, the mixed solution prepared
for the experiments was obtained, mixing
1 part of “Well 1” water and 2 parts of “Well 2”
water).