The invention discloses a
cascade treatment and purification
system and method for a black and odorous river. The
cascade treatment and purification
system comprises a
subsurface flow wetland purification river reach, a surface flow
wetland purification river reach, a near-natural beach land purification river reach and a near-natural
pollution reduction river reach which are sequentially arranged on a
main river channel from a
sewage estuary to a downstream river, an in-situ purification island and a subsurface
wetland are arranged on the
subsurface flow wetland purification river reach, and an internal
electrolysis matrix is arranged in the in-situ purification island; a side groove connected with the
main river channel is formed in the surface flow wetland purification river reach, and a surface flow
constructed wetland is arranged in the side groove; a side seepage
ditch with the head end and the
tail end connected with the
main river channel is arranged on the near-natural beach land purification river reach, and side seepage walls are arranged on the two sides of the side seepage
ditch respectively; and a river center island is arranged on the near-natural
pollution reduction river reach, and indigenous
stain-resistant plants are planted on the river center island and the main river channel. The
system and method are suitable for treatment and purification of heavy-
pollution black and odorous rivers lack of natural runoff, and main incoming water of the heavy-pollution black and odorous rivers is treated town
sewage and industrial
wastewater.