| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an improved method for treating waste water containing fluoride ions by adding a mixture of circulated sludge and a calcium compound to the waste water containing the fluoride ions so as to be capable of solving the problem of pipe clogging and of a stable and continuous operation for a long time. <P>SOLUTION: The method employs a waste water treatment apparatus mainly comprising a reaction tank 1, a settlement tank 2 for settling the sludge containing insoluble substances generated in the reaction tank 1, a mixer tank 3 for mixing the calcium compound and the thickened sludge drawn out through a sludge returning pipe 22 connected to a sludge discharging pipe 21 leading up to the bottom of the settlement tank 2 and for delivering the resultant mixture liquid to the reaction tank 1, and a sludge drawing pump 4 attached to the sludge discharging pipe 21 on the upstream side of the sludge returning pipe 22. The method also includes a cleaning process for each pipe by operating the valves V1 to V4. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
