Free-water-surface cascaded ecological wetland and water purification method thereof

Abstract

The invention relates to a free-water-surface cascaded ecological wetland and a water purification method thereof. The free-water-surface cascaded ecological wetland comprises a bank slope, and further comprises a synchronous nitrification-denitrification functional zone, an aquatic plant pollution-reducing functional zone, a porous medium filter bed filtration and phosphorus removal functional zone and a submerged plant ecological diversity restoration functional zone sequentially arranged along a water flow direction. The water inlet of the free-water-surface cascaded ecological wetland is provided with a wetland water inlet weir plate, and the effluent outlet of the free-water-surface cascaded ecological wetland is provided with a wetland effluent weir plate; the bank slope is providedwith an ecological slope protection structure with a slope of no more than 1 / 3; and the ecological slope protection structure comprises submerged plants, emergent plants and terrestrial plant belts planted from the bottom of the slope to the top of the slope. The functional zones of the free-water-surface cascaded ecological wetland in the invention are specially designed and constructed accordingto the requirements of water purification, so organic matters, suspended matters and nitrogen and phosphorus nutrients are effectively removed; COD, NH3-N and TP in wetland effluent meets requirements on class-IV water quality; the concentration of TN is less than 10 mg / L; and the wetland effluent meets requirements on general landscape water and has the same biodiversity index as general landscape water.

Description

technical field [0001] The invention relates to a free water surface cascade ecological wetland and a water quality purification method thereof, and belongs to the technical field of water environment ecological restoration and water quality purification engineering. Background technique [0002] At present, the water quality of tail water of urban sewage treatment plants implements Class A (GB18918-2002) or even stricter standards, such as quasi-IV water quality (except for TN not higher than 10mg / L, COD, NH3-N and TP and other requirements The purpose is to achieve excellent water quality and eco-friendliness of the treated tail water. Therefore, the sewage treatment process generally requires the effective removal of refractory organic matter and nitrogen and phosphorus nutrients. [0003] Traditional ecological treatment methods, such as multi-habitat oxidation ponds, subsurface flow constructed wetlands, and surface flow constructed wetlands, as the follow-up water puri...

AI Technical Summary

Problems solved by technology

Generally speaking, oxidation ponds and wetland units can make full use of topographical conditions, and use waste rivers and swamps with low agricultural value. The treatment system consumes less energy, is simple to maintain, has a short construction period, and is easy to construct. Large land area, unstable operation effect, poor environmental sanitation, etc. In order to strengthen the removal of organic matter, enhanced operation methods such as aeration are often adopted, resulting in high turbidity of effluent and unstable water quality

Surface flow wetlands and subsurface flow wetlands are the main forms widely used in sewage ecological treatment processes. The hydraulic load or surface load of subsurface flow wetlands is relatively high, but the matrix filling volume is large, easy to block, operation management is complicated, and the project cost is high; Surface flow type Constructed wetland has free water surface, simple operation and management, but low hydraulic load, shallow water level and large area

A single type of subsurface flow wetland or surface flow wetland cannot be applied to the advanced treatment of large-scale sewage treatment plant tail water and low-pollution sewage of similar water quality due to many application limit factors

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