| 摘要 |
An improved method and apparatus for purifying liquid in a square or rectangular tank involving ultra violet (UV) treatment, oxidation, flotation, filtration, effluent purging and disinfection is described. The liquid to be treated is fed into the mixing chamber of the apparatus in the presence of UV light and an oxident (ozone and/or hydrogen peroxide), and then discharged into the flotation chamber for gas stripping of volatile organic compounds (VOC) and flotation removal of floating substances. The subnatant in flotation chamber flows downward through multiple automatic backwash liquid phase granular activated carbon (GAC) filters for final polishing before being discharged as the liquid effluent or further disinfected. The flotation chamber is hooded for collection of gas stream which is moved by a gas mover and purified by a gas phase granular activated carbon (GAC) filter. The gas effluent from said gas phase GAC filter is recycled to said flotation chamber for reproduction of gas bubbles, and elimination of secondary air pollution. The multiple liquid phase GAC filters when dirty are backwashed by backwash means comprising a backwash hood, mechanical gears, backwash pump(s), solid-liquid separators, and control means which are mounted on a moving carriage. During backwash, the backwash hood which has identical shape of a liquid phase GAC filter sits on the top of a liquid phase GAC filter, and the liquid phase GAC is suspended and washed by backwash pump(s) using clean water. The dirty backwash wastewater is recycled to the intake header for water treatment thus eliminating secondary water pollution. The floating substances on the liquid surface of said flotation chamber are skimmed off by a removal mechanism for disposal as the waste sludge. The liquid phase GAC when its regeneration is due is pumped out from a liquid phase GAC fiter as a slurry by said backwash pump(s), and is separated by a solid-liquid separator for regeneration. A built-in purge system recycles a portion of said liquid phase GAC filter effluent for repeated treatment during filter backwash, thus upgrading the effluent quality. |
