| 摘要 |
<p>PROBLEM TO BE SOLVED: To execute a biological treatment of an org. sewage without causing a sludge to foam in an ozone contact tank, eliminating the need of a device detoxicating a waste gaseous ozone and hardly generating a surplus sludge with a simple process. SOLUTION: In this treating method, after subjecting the org. sewage to the biological treatment, a biological sludge flowing out from a biologically treating tank is subjected to a solid-liq. separation, and a treated water is discharged out of system, and a separated sludge 7 is returned to the biologically treating tank. In this case, a branch sludge passage 10 is provided at a return sludge passage 9 for returning the separated sludge 7 to the biologically treating tank to make two line passages, and ozone is injected to the branch sludge passage 10 to ozonize the sludge in the passage and to make a soluble sludge, which is returned to the biologically treating tank while containing a residual ozone in the soluble sludge.</p> |
