| 摘要 |
<p>PROBLEM TO BE SOLVED: To heighten the purifying rate to miniaturize a septic tank by providing at least an anaerobic sludge digesting chamber and an aerobic active sludge chamber, installing a membrane separator for filtering sludge liquid in each tank thereof and also returning a part of filtrate permeated through the membrane separator of the aerobic active sludge chamber to the anaerobic sludge digesting chamber. SOLUTION: A body of a septic tank is divided into an anaerobic sludge digesting chamber 3 and an aerobic active sludge chamber 4 by a partition wall 2, and raw water (sludge) is fed into the anaerobic sludge digesting chamber 3 through a raw water introducing pipe 5. A flat membrane type separator 6 is immersed and installed in the anaerobic sludge digesting chamber 3, and sludge liquid in the anaerobic sludge digesting chamber 3 is sucked and filtered by operating a suction pump 7. The filtrate is introduced into the aerobic active sludge chamber 4 to which air is fed through a diffusing pipe 11 by a blower 10, and is subjected to aerobic treatment. A membrane separator 9 is also arranged in the sludge chamber 4, and sludge liquid in the sludge chamber 4 is sucked and filtered by a suction pump 12, and a part of the filtrate is returned to the anaerobic sludge digesting chamber 3 through a returning pipe 15.</p> |
