Liquid waste treatment apparatus

A liquid waste treatment apparatus comprising:

• a reaction tank having a double-tube structure including an outer tubular body in a tubular form and an inner tubular body in a tubular form disposed inside the outer tubular body, the liquid waste treatment apparatus being configured such that, under a condition where the inner tubular body into which a fluid is introduced is cantilevered by the outer tubular body in a downstream end portion of the inner tubular body in a fluid transport direction, organic matter in a treatment-object fluid undergoes oxidative decomposition in a process in which the treatment-object fluid and an oxidizing agent are mixed together, heated and pressurized while introduced into the inner tubular body, and the treatment-object fluid and the oxidizing agent in the inner tubular body are transported toward the downstream end portion along a tube longitudinal direction,
• wherein the inner tubular body is provided with a protruding portion protruding from an outer peripheral surface of the downstream end portion of the inner tubular body and extending around the whole periphery of the outer peripheral surface, and an upstream end of the protruding portion in the fluid transport direction is pressed by a pressing device toward a downstream end of the outer tubular body in the fluid transport direction along the tube longitudinal direction, whereby the inner tubular body is cantilevered by the outer tubular body.