Four principles should be followed in sewage treatment

1. Respect nature. This principle is the guiding principle and the basis of other principles. It includes increasing the infiltration capacity of green land, gravel ground, permeable pavement and natural rainwater, using buildings, parking lots, squares and roads to build rainwater collection and utilization facilities, and reducing rainwater runoff, which embodies the concept of low impact development and respect for nature.

2. Comprehensive utilization. A series of institutional measures have been formulated to promote the reuse of sewage and the reuse of sludge and rainwater.

3, "overall planning and supporting construction". Two supporting facilities should be ensured: one is the urban development and the construction of urban drainage and sewage treatment facilities; the other is the supporting of various subsystems of urban drainage and sewage treatment facilities.

4. To "ensure safety". To ensure the safe and stable operation of drainage and sewage treatment facilities is the basis for the realization of water social circulation.