适用于雨水稀少且排水受纳水体环境容量大，一定量的污水对河道不形成影响的

Applies to scarce rainfall and drainage receiving water environment capacity, a certain amount of water on the river does not affect the formation of the region. The more abundant rainfall in Zhejiang province, the narrow part of the river, the sewage mixed with water, a greater impact on the environment, so the implementation of limitations

It is suitable for areas where rainwater is scarce and drainage is large in the environmental capacity of the water body, and a certain amount of sewage does not affect the river. Zhejiang region is more abundant rain, some of the river narrow, sewage mixed into the water body, the environmental impact is greater, so the implementation has limitations

It is suitable for the area where the rainwater is scarce and the environmental capacity of the receiving water body is large, and a certain amount of sewage has no impact on the river channel. However, in Zhejiang Province, there are plenty of rainwater, some rivers are narrow, and the sewage mixed into the water has a great impact on the environment, so the implementation is limited