Together with iron chloride, lime participates in phosphorous precipitation. Phosphorous removal using lime and iron chloride is commonly applied in WWP's.
Fe3+ +PO43-® FePO4¯(pH: 6 - 7)
3 Ca2+ + 2 PO43-® Ca 3(PO4)2¯(pH: 9 -12)
Phosphorous is removed and precipitated in the dewatered sludge, increasing herewith its agronomic value.
