| 摘要 |
<p>PURPOSE:To permit the highly efficient treatment of waste water at lower cost by the procedure in which part of granular medium to which aerobic microorganisms are adhered is treated with unaerobic bacteria and then sent back to aerobic treatment portion for reuse. CONSTITUTION:After removing BOD and NH4-N present in waste water by oxidation by means of an aerobic microorganisms-adhered granular medium in the aerobic biological treatment portion, th effluent is introduced into a biological denitricafition portion, whereupon part of the microorganism-adhered granular medium is treated in an unaerobic fermentation tank and then returned in parts to the denitrification portion and the aerobic biological treatment portion. For example, part of the microorganism-adhered granular medium 2 in the aerobic biological treatment tank 1 is introduced through the conduit 10 to the unaerobic fermentation tank 11 and stirred for several days. The microorganism film on the surface of the granular medium in the tank 11 is decayed and removed and slurry containing part of granular medium is then introduced through the conduit 13 into the biological denitrification tank 7, and remaining granular medium is sent back to the tank 1 through the return pipe 12.</p> |
