| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an improved combined septic tank easy in manufacturing, small in size and installation space, improved in mechanical strength, small in power consumption and easy in operation and maintenance. SOLUTION: This septic tank is used for treating household wastewater at its generation site and consists of three reaction parts. In the first reaction part 1, the precipitation/separation of the solids and the anaerobic decomposition of the organic matter in the wastewater to be flown in are sequentially carried out as a time elapses. In the second reaction part 2 easy in treating sludge on the bottom, the denitrification and nitrification of the wastewater treated in the first part are carried out while circulating it internally through an oxygen-free part 2A and an aeration part 2B that are communicated with each other through the bottoms. In the third reaction part 3, the sludge is filtrated by a filter medium and precipitated/concentrated on the bottom and then collected by a floater to send them intermittently to the first reaction part 1.</p> |
