| 摘要 |
PURPOSE:To lessen the necessary surface area for installation and make operation and maintenance easy by adding an acid to ammoniac nitrogen-containing wastewater to give an ammonium salt and acidic condensate demineralized regenerated water, removing solid particles with a prescribed particle size or larger by a hollow yarn membrane filter, then lowering ammonium ion by electrodialysis, and after that, carrying out drying process by a centrifugal membrane dryer. CONSTITUTION:While being stirred in a pH adjusting tank 1 by a stirrer 1a, condensate demineralized regenerated water (a) is mixed with an acid (b) such as hydrochloric acid to adjust pH to be 4 or lower. Ammoniac nitrogen is thus removed as an ammonium salt. Then, the resulting water is sent to a hollow yarn membrane filter 3 by a pump 2 to remove solid particles with 0.1mum or larger particle size. Furthermore, electrodialysis is carried out for the treated water by a first electrodialyser 4 and a second electrodialyser 5 to decrease ammonium ion and other inorganic ions. Water is supplied to the condensing side 5b of the second electrodialyser 5 through a pipe(p) and returned to the first electrodialyser 4 and together with condensed water of the first electrodialyser 4, the water is sent to a centrifugal thin membrane drying apparatus 6, w-where drying is carried out. |
