Washing machine appliance with a removable filtering agitator

A washing machine appliance, comprising:

• a tub;
• a basket rotatably positioned within the tub;
• an impeller base rotatably mounted within the basket and defining a rotation axis, the impeller base comprising
• one or more impeller fins extending radially outward from the rotation axis, and
• a mounting face disposed radially inward from the one or more impeller fins, the mounting face comprising a central bracket defining a mounting channel having an axial portion and a radial portion extending along the mounting face;
• an impeller cap slidably seated within the central bracket and biased upwardly;
• and
• an extended post removably attached to the impeller base and configured to rotate therewith, the extended post defining an inlet and an outlet, the extended post comprising:
• a connector column extending along the rotation axis between a bottom end proximal to the impeller base and a top end distal to the impeller base, the connector column comprising a filtration wall defining a filtration chamber,
• a shader collar disposed about the connector column, and
• a trap positioned at the top end of the connector column.