Method and system for comprehensively purifying, collecting and utilizing overpass rainwater

The invention relates to a method and system for comprehensively purifying, collecting and utilizing overpass rainwater. The system disclosed by the invention comprises a rotational flow separation module, a high-efficiency purification module and a plastic water storage module. According to the method, based on the principle of gravity rotational flow sand setting technology and absorption, filtration and purification technology, emission, collection and purification of overhead overpass rainfall runoff are realized, suspended particles and organic and inorganic pollutants are respectively eliminated efficiently; furthermore, water storage and reuse are carried out to form integrated comprehensive technology for collecting and reusing purified rainwater; multiple effects such as fast elimination of rainwater on an overpass, water-saving irrigation of a green belt below an overpass and pollution control of overpass roadway runoff can be achieved simultaneously; and the method and the system for comprehensively purifying, collecting and utilizing overpass rainwater disclosed by the invention have wide application prospect in the fields of municipal construction and non-point source pollution control.