| 摘要 |
<p>In a sewage purification system which is formed by digging a hole of a definite size into the ground close to a house, placing a concrete sewage tank therein, piling up a block in a definite shape on the top opening of the sewage tank, thus forming a microbial growth layer and then burying the system in the ground, it is feared that when a large amount of water flows into the sewage tank, the sewage flows back through a drainage pipe and then overflows from a drainage outlet or the like in the house. A sewage purification system wherein a block-piling part is formed by piling up a plurality of blocks and burying in the ground and the frond end of a connecting pipe branched from a sewage-supplying pipe is located in the block-piling part. Owing to this constitution, a large amount of water rapidly flowing into the sewage tank can be smoothly penetrated into the ground and the back flow of the sewage in the sewage-supplying pipe can be prevented as far as possible.</p> |
