Saponification occurs
between un-reacted FFAs and calcium on the solid core matrix
to form more saponified solids that result in FOG deposit
accumulation on sewer pipe walls. Because of the adhesive
character, surface charge, and flow restrictions in sewer lines,
debris in wastewater would also accumulate and result in the
formation of debris layers interspersed with hardened FOG.
These layers have been identified in previous research