| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method and a device for treating an organic wastewater capable of suppressing the generated amount of excessive sludge accompanying a biological treatment and capable of saving a required energy. SOLUTION: In the biological treatment method that, after the organic wastewater is treated with an activated sludge in a bio-reactor, a part of the biological sludge is extracted from a biological treatment system where the organic wastewater is solid-liquid separated into a treated water and a settled sludge with a solid-liquid separator, the extracted biological sludge and a high- concentration oxygen gas containing ozone are mixed and contacted in an ozone contact tank, and the sludge after contacted with the ozone is returned to the biological treatment system, there are provided the biological treatment method and the treatment device of the organic wastewater that an exhaust gas from the zone contact tank is sucked and is supplied to the aerobic section of the bio-reactor, and when the pressure of the ozone contact tank gets lower than the atmospheric pressure, the air is supplied to the ozone contact tank, or the air is supplied to an exhaust piping from the ozone contact tank.</p> |
