Abstract: An adjustable stirring device for agitating non-homogeneous waste materials in structures having ingress/egress ports of a predetermined size. The device has a collapsible agitator assembly with a size greater than that of the ingress/egress port when in its expanded and operative state. The agitator assembly has a hub and at least one pivotally attached blade, which is constructed and arranged so that the blade is collapsible for insertion and removal from the ingress/egress port. The agitator assembly and its blades are of a certain configuration for use in municipal and agricultural waste structures. The device is further provided with an adjustable drive shaft assembly connected to the agitator assembly. A frame structure is provided for supporting the drive member assembly and for aligning the agitator assembly in an operative position.