The high P removal efficiency in the AMAK process resulted
from the transformation of practically all calcium phosphates in the
treated manure into a hydroxyapatite phase that had very low
solubility in water and was practically insoluble in alkali. The
crystalline hydroxyapatite served as a filtration aid that improved
the effectiveness of the filtration process, and consequently, it
increased the filtration rate of the treated manure slurry. The AMAK
treatment process simultaneously resulted in the coagulation of a
considerable amount of the organic phase, which contained micro
particles, and this phase was incorporated into the sediment