NOVELTY - The system has electrolyzer (3) or electrodialyzer that processes by supplying with electricity to to-be-processed water. The hydrogen gas and oxygen gas containing water which flow out of electrolyzer are water-flowed to a catalyst apparatus (4) with which hydrogen-burning catalyst is filled in a gas-liquid mixed state. The hydrogen-burning catalyst is a catalyst which made support which consists of hydrophobic materials support platinum group metal.    USE - Water treatment system for electrically processing to-be-processed water such as natural water. Can also be used for treating waste-water of human body effluent water such as urine, perspiration, domestic waste water, kitchen waste-water, laundry waste-water, bath and shower waste-water, cleaning waste-water, waste-water of animals and plants.    ADVANTAGE - The danger of the explosion by hydrogen/oxygen mixed gas accumulating is avoided in order to return to water by hydrogen burning reaction, without carrying out gas-liquid separation of the fluid which contains hydrogen gas and oxygen gas emitted in an electrical process of water, so that the gas for being diluted is avoided. The necessity of gas-liquid separator or condensing apparatus is avoided, so that the structure of the water treatment system is simplified. Since the water generated by hydrogen-burning reaction returns to the treated water, the high water recovery is obtained.    DETAILED DESCRIPTION - The human body effluent water and/or domestic waste water which arose in closed-system space are processed as to-be-processed water. The treated waters are collected as product water. The water flow of the catalyst apparatus is 1-1000 hr-1. An INDEPENDENT CLAIM is included for water-treatment method.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the water treatment system.(Drawing includes non-English language text)    Natural water tank (1)    Electrolyzer (3)    Catalyst apparatus (4)    Natural water line (11)    Transfer line (12)