| 摘要 |
<p>Wastewater is pumped from a tank by means of an airlift pump (6), pressurized air being led to the lower portion of an upward-leading pipe portion (7) in the airlift pump (6). Before discharge pumping of the wastewater, the contents of the pipework of the airlift pump (6) are pumped into the tank for instance by leading back the contents of the pipework through a return pipe (22) or by subjecting the pipework to return flushing. <IMAGE></p> |
