Abstract: A portable, rollable container unit is adapted to be removably received in a power unit. The units have means for positively guiding the container unit into the power unit and a ram in the power unit is operable to compact material in the container unit. The apparatus includes means responsive to the container unit being fully received in the power unit for enabling the ram unit and for inhibiting operation of the ram unit when the container unit is not fully received in the power unit. The container has an openable wall door section and means is provided for inhibiting opening of the door section of the container when the container unit is received in the power unit.