TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Device: The anaerobic digester comprises biogas off-take arrangement for removing biogas generated by anaerobic digestion from the drum. The internal matter displacing formation is in the form of mixing blade that extends in curved manner along the internal surface of the drum and extends generally in a direction of length along the drum. The anaerobic digester has two mixing blades arranged such that the blades are substantially diametrically opposed to each other on the internal surface of the drum, and each mixing blade extends in a generally helical fashion in the direction of length along the drum. The mixing blade has a width of 30-120 mm and extends substantially orthogonally away from the internal surface of the drum, and each mixing blade has one edge that is attached to the internal surface of the drum and another edge that is free and is spaced away from the internal surface of the drum. The drum has a axis of rotation, where the drum is orientated such that the drum axis of rotation extends at an angle of 0-30 degrees to horizontal orientation. The anaerobic digester comprises drum orientation adjustment arrangement for enabling the orientation of the drum relative to a horizontal orientation to be adjusted to suit the properties of organic matter being treated within the drum. The anaerobic digester comprises drive arrangement on the support for rotating the drum on the support, and the drive arrangement enables operator to rotate the drum in either direction of rotation on demand. The drive arrangement includes motor that drives a shaft which in turn drives a drive flange that is driveably coupled to the other end of drum to rotate the drum. The support includes base for mounting on a support surface, and two longitudinally spaced support formations projecting up from the base on which the drum is supported towards each end, and one support formation includes two laterally spaced rollers on which the drum rotates and the other support formation includes the drive flange which is driveably coupled to the drum. The feed/discharge arrangement defines an opening through which non-gaseous raw matter to-be-treated is fed into the digester and through which non-gaseous treated matter is discharged from digester, and a seal for sealing off the opening from external environment when raw matter is fed into the drum and when treated matter is withdrawn from the drum. The seal is water seal that is positioned between the interior space of container and external environment to resist passage of air from the outside environment into the drum. The feed/discharge arrangement has two ends and is mounted on one end of the drum and projects away from the one end of drum in a direction of the longitudinal axis. The feed/discharge arrangement includes at least one feed/discharge matter displacing formation on the internal drum surface that feeds matter into the interior space when the drum is rotated in one direction and discharges matter from interior space when the drum is rotated in opposite direction. The feed/discharge matter displacing formation is a screw formation (42, 44) having helical configuration extending from one end of the feed discharge arrangement to the other end such that rotation of the drum in one direction causes the helical formation to physically displace organic matter towards interior space and rotation of drum in opposite direction causes the screw formation to physically discharge organic matter out of the interior space. The feed/discharge arrangement includes outer cylindrical formation, inner cylindrical formation and annular space defined between the outer and inner cylindrical formations, and each screw formation extends across the annular space between the outer and inner cylindrical formations and is sealed to the outer and inner cylindrical formations. The feed/discharge arrangement comprises two screw formations and each screw formation is connected to the mixing blade to effectively form extension of associated mixing blade within the interior space of the drum. The drum biogas off-take arrangement includes gas collection head and off-take conduit operatively connected to gas collection head for drawing biogas off operatively upper region of the drum in head space above solid or liquid organic matter within the drum, and a non-return valve in line with the off-take conduit for resisting flow of biogas in reverse direction back into the drum. The outer container is in the form of elongate rectangular container having container interior space that can receive the digester with sufficient clearance for digester to rotate within outer container. The outer container comprises heating arrangement for engineering the temperature within the digester to promote anaerobic digestion within the digester. The outer container includes fluid that is air surrounding the digester, where the heating arrangement heats up the air surrounding the digester and temperature of organic matter within interior space of the drum. The heating arrangement comprises heat exchanger comprising heat transfer tubes within the outer container, and heat transfer fluid is passed through the heat transfer tubes to heat up the air within the outer container. The heat transfer fluid includes heat transfer gases from generator or boiler that is located proximate to the apparatus. The heating arrangement for heating the interior space of the surround container includes solar heat exchanger that is exposed to solar rays from the sun, which is operatively connected to the heat exchanger within the outer container to use solar energy to heat up the air. The outer container comprises top wall, bottom wall and sidewall comprising several sidewall portions, where the outer container includes thermal insulating material extending across the top wall, bottom wall and the sidewall to retard the loss of heat from the container interior space through the walls of the container. The outer container is intermodal shipping container having attachment formations that enables the container to lift up and mount on transport vehicle to transport from one location to another location. The surround container is intermodal shipping container that enables the container to handle and ship from one location to another using standard container shipping and handling equipment. The apparatus comprises biogas storage vessel in the form of a storage tank that is operatively coupled to the off-take conduit for storing biogas that is generated in the drum of the digester and the biogas storage vessel is positioned outside of the outer container. Preferred Method: The method involves feeding raw organic waste into the interior space through a feed/discharge arrangement. The method involves raising temperature within the digester to a temperature above that of external environment to increase the rate at which anaerobic digestion occurs within the interior space of the drum. The method involves heating air in the container space by heat exchanger using heat obtained from solar energy or combustion of carbon in a generator or engine.