PROCESS AND DEVICE FOR WATER TREATMENT

PURPOSE:To purify raw water by means of a simple structure without using chemicals by making dissolved oxygen of high density contained in raw water from which underwater floating matters such as green algae are separated, and then carrying out the oxidative decomposition of nitrogen components by means of physiological filtration and the sterilization by means of emission of ultraviolet rays. CONSTITUTION:Raw water W in a lake, a marsh, an artifitial pond L or the like is pumped by a storage pump 1 and fed into an overflow type separation tank 2 through a current force attenuating section 22, and physical separation and removal of underwater floating matters S like green algae andothers are carried out in the separation tank. Raw water W coming out of the separation tank 2 is fed into a physiological filtration section 4, and a part of water is returned to the separation tank 2 through an oxygen feed section 3 on the way. The oxygen feed section 3 is provided for the purpose of increasing the dissolved oxygen contained in the raw water W by blowing air A into the raw water W, and is composed of a water feed pump 31, a pressurizing tank 32 and an air compressor 33. A biological filtration is performed in the physiological filtration section 4 by aerobic bacteria, and then sterilized by a sterilization lamp 51 of an ultraviolet sterilization section 5.