| 摘要 |
<p>PROBLEM TO BE SOLVED: To establish a purifying means generating no environmental polution and gentle to environment by subjecting a photographic waste soln. to biological denitrification treatment and subjecting the treated soln. to biological treatment and biological nitration treatment in the presence of active carbon and returning a part of the waste soln. after nitration treatment to a denitrification treatment process. SOLUTION: A photographic waste soln. is treated by subjecting the waste soln. to biological denitrification treatment and subjecting the treated soln. to biological treatment and biological nitration treatment in the presence of active carbon and returning a part of the waste soln. subjected to nitration treatment to a denitrification process. That is, easily decomposable org. matter is decomposed simultaneously with the denitrification of nitrate ions returned to a nitration process and, at the same time, dissolved silver is removed and, thereafter, a remaining hardly decomposable component is biologically treated in the presence of active carbon to be decomposed. Therefore, a hardly decomposable component can be decomposed in an extremely effective manner as compared with a method biologically treating the photographic waste soln. in the presence of active carbon from the beginning in such a state that an easily decomposable component and a hardly decomposable component are mixed.</p> |
