An apparatus for mixing a non-homogeneous fluid comprising liquid in a container, comprising: a tubular pump housing having an exterior surface and first and second opposing end portions (12a, 12b) each suitable for passage of the fluid therethrough, the first end portion including at least a first opening for receiving the fluid into the pump housing and the second end portion including at least a second opening for emitting the fluid within the container; and a threaded shaft positioned within the pump housing to act as a screw conveyor, the pump housing and the shaft forming an assembly to circulate the fluid within the container, and wherein: when the assembly is immersed in a non-homogeneous portion of the fluid and the shaft undergoes rotation with respect to the pump housing, a portion of the non-homogeneous fluid enters the housing through the first opening, exits the pump housing through the second opening and travels along the pump housing exterior surface to effect circulation and mixing of fluid circulating through the assembly thereby improving homogeneity of the fluid; an adapter connected to the pump housing and providing a connection interface for coupling the threaded shaft to a motor positionable outside the container to effect rotation of the shaft within the container, characterised in the adapter interface including (i) an upper body section having an opening sized to fit about a lower housing section of the motor; and (ii) and a lower body section for attachment to the pump housing to securely attach the pump housing to the lower housing section of the motor through the adapter; and a collar attached to the second end portion of the pump housing, the collar having an open end with which the collar can be securely affixed to the adapter lower body section, where the lower body section of the adapter includes first threads for attachment to the second end portion of the pump housing, and the collar includes second threads formed along an interior surface thereof, adjacent the open end, to securely affix the collar to the adapter lower body section by mating the first and second threads. a tubular pump housing having an exterior surface and first and second opposing end portions (12a, 12b) each suitable for passage of the fluid therethrough, the first end portion including at least a first opening for receiving the fluid into the pump housing and the second end portion including at least a second opening for emitting the fluid within the container; and a threaded shaft positioned within the pump housing to act as a screw conveyor, the pump housing and the shaft forming an assembly to circulate the fluid within the container, and wherein: when the assembly is immersed in a non-homogeneous portion of the fluid and the shaft undergoes rotation with respect to the pump housing, a portion of the non-homogeneous fluid enters the housing through the first opening, exits the pump housing through the second opening and travels along the pump housing exterior surface to effect circulation and mixing of fluid circulating through the assembly thereby improving homogeneity of the fluid; an adapter connected to the pump housing and providing a connection interface for coupling the threaded shaft to a motor positionable outside the container to effect rotation of the shaft within the container, characterised in the adapter interface including (i) an upper body section having an opening sized to fit about a lower housing section of the motor; and (ii) and a lower body section for attachment to the pump housing to securely attach the pump housing to the lower housing section of the motor through the adapter; and a collar attached to the second end portion of the pump housing, the collar having an open end with which the collar can be securely affixed to the adapter lower body section, where the lower body section of the adapter includes first threads for attachment to the second end portion of the pump housing, and the collar includes second threads formed along an interior surface thereof, adjacent the open end, to securely affix the collar to the adapter lower body section by mating the first and second threads.