| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a UASB waste water treating method in which alkali consumption is reduced and treating cost is cut down and a UASB waste water treating device whose construction cost is lowered. SOLUTION: In an alkali consumption reducing method in a UASB waste water treating method, a part of treated water leaving a UASB tank is returned to the upstream side of the UASB tank to circulate it. A device using this method is provided with a conditioning tank 21 for performing hydrolysis treatment of raw water and acid formation, and a UASB tank 2 for performing methane fermentation in the poststage of the conditioning tank 21. The conditioning tank 21 is divided into a raw water feeding chamber 21a into which raw water flows and a treated water chamber 21b into which treated water flows from the UASB tank 2 by a partition wall 4. In the partition wall 4, a water passage is formed for refluxing a part of the treated water in the treated water chamber 21b to the raw water feeding chamber 21a to make the flow rate of the treated water to the treated, water chamber 21b larger than the feed quantity of the raw water 21a to the raw water feeding chamber 21a.</p> |
