Abstract: A solid-liquid separation apparatus wherein a solid-liquid mixture is introduced into a rotary filtration drum having filter cloth mounted thereon and is allowed to pass through the filter cloth to thereby separate the solids contained therein. The filter cloth has one surface facing the interior of the drum and covered with a napped filter layer which is formed by a multiplicity of fibers having a diameter of 0.1 to 10 .mu.m. The filter cloth preferably has an elongation percentage of not smaller than 1.0%. A base material of the filter cloth includes a weft extending along the rotational axis of the drum and a warp extending in the circumferential direction of the drum. The fibers of the napped filter layer are formed by napping chiefly the weft in the direction of the warp.

Abstract: The device according to the present invention comprises a unidirectionally circulating endless filter cloth with a napped filter layer on the surface, a solid-liquid mixture supply device installed on the front side of filter cloth, a depressurizing suction device installed on the backside of the filter cloth, a non-filterable content withdrawing device installed downstream of the solid-liquid mixture supply device and the depressurizing suction device, and a filter cloth wash device installed downstream of the non-filterable content withdrawing device in the running direction of the filter cloth and located between the non-filterable content withdrawing device and the solid-liquid mixture supply device or the depressurizing suction device. The depressurizing suction device is equipped with a depressurized suction port splaying in the running direction of said filter cloth.

Abstract: A method for biologically purifiying waste water which produces substantially no excess waste sludge is provided. In this method, a waste water containing biodegradable substances is treated in a biological fixed film type reactor and aqueous water sludge discharged from the reactor is aerobically digested after being separated from the biologically treated waste water. The digested aqueous sludge is returned to the reactor or the upstream thereof. This method can be advantageously combined with any installed activated sludge type water purification process, to thereby substantially eliminate the production of excess waste sludge from the water purification system.

Abstract: A solid-liquid separation element which remarkably, improves the solid-liquid separation capacity of a solid-liquid separation device having the separation element therein is provided. In this separation element, guide members for accelerating the through-flow of the liquid are mounted on the back surface of a stationary inclined screen and, optionally, guide members for transporting solid materials are arranged on the surface of the screen so as to be substantially in parallel to each other and in a downward inclining direction from both edges of the screen. The solid-liquid separation apparatus having said separation element and a cleaning brush which is reciprocated in rubbing contact with the back surface of the screen is also provided. The range of the reciprocating motion of the brush is more than the width of the screen.

Abstract: High impact resistant thermoplastic resins are produced in three steps: (a) graft polymerizing a minor amount of unsaturated monomer onto a major amount of diene type rubber polymer in latex form, (b) mixing the grafted diene type rubber latex with a monomer or monomers, extracting the grafted rubber polymer particles into the monomer phase and separating and discarding the water phase to obtain a grafted rubber polymer particle dispersed monomer solution, and (c) bulk polymerizing the resulting rubber polymer particle dispersed monomer solution.