Several of these flow into a branch sewer, which joins first a sub-main and then a main sewer taking it to the treatment plant.

这些街道污水管又相结一条污水支管。此支管与次干管连接，然后经主干管将污水送至污水处理厂。

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Several of these flow into a branch sewer, which joins first a sub-main and then a main sewer taking it to the treatment plant.

这些街道污水管又相结一条污水支管。此支管与次干管连接，然后经主干管将污水送至污水处理厂。

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