Abstract: According to one embodiment, a membrane filtration system includes a raw water tank, a first tank, a second tank, a nanofiltration membrane module comprises a nanofiltration membrane, and removes the solute from the raw water with a solute removal rate of 1% to 30%, a first pump for supplying the raw water from the raw water tank to the module to cause the raw water to permeate through the membrane and send the water that has permeated through the membrane as a primary water to the first tank, a RO module comprises a RO membrane that further removes the solute from the primary water, and a second pump for supplying the primary water from the first tank to the RO module to cause the primary water to permeate through the membrane and send the water that has permeated through the membrane as a secondary water to the second tank.

Abstract: A treatment apparatus for organic waste including a reaction vessel for introducing and decomposing organic waste and pulling out decomposed organic waste as a treated fluid. The reaction vessel includes an internal vessel made of corrosion-resistant material, an external vessel made of pressure-resistant material provided for surrounding the internal vessel via a gap, and an interconnection pipe for interconnecting the gap and the internal vessel outside the external vessel, thereby to control inside the gap and inside the internal vessel to practically equal pressure. The internal vessel has a heating zone for heating the introduced organic waste to a temperature higher than a critical point of water, a reaction zone for holding and decomposing the organic waste at a temperature higher than the critical point of water, and a cooling zone for cooling the treated fluid containing a decomposition product of the organic waste to lower than 100° C.

Abstract: A treatment apparatus for organic waste including a reaction vessel for introducing and decomposing organic waste and pulling out decomposed organic waste as a treated fluid. The reaction vessel includes an internal vessel made of corrosion-resistant material, an external vessel made of pressure-resistant material provided for surrounding the internal vessel via a gap, and an interconnection pipe for interconnecting the gap and the internal vessel outside the external vessel, thereby to control inside the gap and inside the internal vessel to practically equal pressure. The internal vessel has a heating zone for heating the introduced organic waste to a temperature higher than a critical point of water, a reaction zone for holding and decomposing the organic waste at a temperature higher than the critical point of water, and a cooling zone for cooling the treated fluid containing a decomposition product of the organic waste to lower than 100° C.

Abstract: A high-pressure treatment apparatus comprises a first solid reservoir, a second solid reservoir connected to the first solid reservoir through a first connecting pipe, a high-pressure reactor connected to the second solid reservoir through a second connecting pipe, means for feeding reaction medium into the high-pressure reactor, a first sealing unit and a second sealing unit intervened respectively in the first connecting pipe and second connecting pipe, a first fluid feed unit for feeding a first fluid between the first sealing unit and the second sealing unit, a second fluid feed unit for feeding a second fluid between the second sealing unit and the high-pressure reactor, and means for opening the second sealing unit at the time of shut-off of the first sealing unit and controlling the first fluid and the second fluid to form a pressure-gradient so that pressure between the first sealing unit and the second sealing unit and pressure between the second sealing unit and the high-pressure reactor decrease gr

Abstract: A waste processing method decomposing an organic substance or an inorganic substance contained in organic wastes or inorganic wastes by holding a mixture of the organic wastes or the inorganic wastes and a medium, which is in its supercritical state, for a pre-determined time period, in which the hydrogen ion concentration of the medium is 10.sup.-4 mol or more to 1 kg of the medium.A waste processing method having a step of decomposing all or almost all of an organic substance included in organic wastes into lower-molecular-weight products by holding the organic wastes in a medium, which is in its supercritical state, for a pre-determined time and a step of oxidizing and decomposing the lower-molecular-weight products into carbon dioxide (CO.sub.2) and/or water (H.sub.2 O) by holding a mixture of an oxidant and the lower-molecular-weight products in the medium, which is in its subcritical state, for a pre-determined time period.