Continuous purifying system for bay water quality as well as treatment method and application thereof

The invention discloses a continuous purifying system for bay water quality as well as a treatment method and application thereof. The system built by bottom lands such as a natural bay has the functions of sand settling, secondary biochemical treatment, precipitation, deep purification and the like and is matched up with hydraulic structures such as a channel flap gate, so that the system can meet that all or part of river water automatically flows in or out of the treatment system in a dry season, floodwater is drawn off preferentially in a rainy season, and the channel water quality can be restored and guaranteed to be prior to landmark type V water under a controllable condition. The system adopts an integrated design, so that the structure is compact and the construction and operation cost is cheap; furthermore, the system adjusts measures to local conditions according to field conditions and a water quality target, and different water quality purifying units are flexibly selected and combined, so that the system has excellent water quality purifying capacity and good landscaping effect. The continuous purifying system for the bay water quality is convenient to operate and low in cost, and can be massively popularized and applied to polluted medium or small rivers in cities, so that better economic and social benefits are gained.