A compaction apparatus comprising: a hopper receiving materials; a container storing the materials in a compacted fashion; and a screw conveyor system comprising: a screw conveying the materials from the hopper to the container and including a proximal segment extending in the hopper; a passageway structure traversed by the screw, separating the hopper from the container, the passageway structure allowing passage of the materials between the hopper and the container, the passageway structure comprising: a main passageway shaped to be in close relation to a circumferential perimeter of the screw; and a by-pass passageway extending outwardly beyond the circumferential perimeter of the screw and offset from the main passageway, wherein the screw comprises a helical screw blade having an outer edge, wherein the passageway structure defines an asymmetrical aperture, wherein the screw comprises: a screw shaft; a helical screw blade extending around the screw shaft; and a screw head plate affixed to an end of the screw shaft and extending perpendicularly thereto, characterised in that the screw includes a distal segment extending in the container; and the helical screw blade comprises a first group of flights along the proximal segment and a second group of flights differing from the first group of flights along the distal segment, and wherein the first group of flights has a first diameter and the second group of flights has at least one second diameter smaller than the first diameter. a hopper receiving materials; a container storing the materials in a compacted fashion; and a screw conveyor system comprising: a screw conveying the materials from the hopper to the container and including a proximal segment extending in the hopper; a passageway structure traversed by the screw, separating the hopper from the container, the passageway structure allowing passage of the materials between the hopper and the container, the passageway structure comprising: a main passageway shaped to be in close relation to a circumferential perimeter of the screw; and a by-pass passageway extending outwardly beyond the circumferential perimeter of the screw and offset from the main passageway, wherein the screw comprises a helical screw blade having an outer edge, wherein the passageway structure defines an asymmetrical aperture, a screw conveying the materials from the hopper to the container and including a proximal segment extending in the hopper; a passageway structure traversed by the screw, separating the hopper from the container, the passageway structure allowing passage of the materials between the hopper and the container, the passageway structure comprising: a main passageway shaped to be in close relation to a circumferential perimeter of the screw; and a by-pass passageway extending outwardly beyond the circumferential perimeter of the screw and offset from the main passageway, a main passageway shaped to be in close relation to a circumferential perimeter of the screw; and a by-pass passageway extending outwardly beyond the circumferential perimeter of the screw and offset from the main passageway, wherein the screw comprises a helical screw blade having an outer edge, wherein the passageway structure defines an asymmetrical aperture, wherein the screw comprises: a screw shaft; a helical screw blade extending around the screw shaft; and a screw head plate affixed to an end of the screw shaft and extending perpendicularly thereto, characterised in that the screw includes a distal segment extending in the container; and the helical screw blade comprises a first group of flights along the proximal segment and a second group of flights differing from the first group of flights along the distal segment, and wherein the first group of flights has a first diameter and the second group of flights has at least one second diameter smaller than the first diameter. a screw shaft; a helical screw blade extending around the screw shaft; and a screw head plate affixed to an end of the screw shaft and extending perpendicularly thereto, characterised in that the screw includes a distal segment extending in the container; and the helical screw blade comprises a first group of flights along the proximal segment and a second group of flights differing from the first group of flights along the distal segment, and wherein the first group of flights has a first diameter and the second group of flights has at least one second diameter smaller than the first diameter.