Combined subsurface-flow constructed wetland system with high efficiency and low cost for processing polluted river water

Abstract

The invention relates to a combined subsurface-flow constructed wetland system with high efficiency and low cost for processing polluted river water. The system is formed by combing a first-stage vertical subsurface-flow wetland and a second-stage horizontal subsurface-flow wetland, wherein the vertical subsurface-flow wetland comprises a box body (1), a water inlet distribution pipe (2), vertical stand pipes (3), a water outlet collection pipe (4), a water outlet hose (5), a heightened base (6), a furnace slag packing layer (7) and a gravel packing layer (8); the horizontal subsurface-flow wetland comprises a box body (9), a water inlet distribution pipe (10), a porous barrier (11) of a water inlet distribution area, a porous barrier (12) of a water outlet area, a water outlet collection pipe (13), a water outlet hose (14), fixed water level outlets (15), a furnace slag packing layer (16) and a gravel packing layer (17). By adopting the combined subsurface-flow constructed wetland system, total nitrogen and phosphorus in the river water can be effectively removed, the height of the water outlet hose of the vertical subsurface-flow wetland can be adjusted to change the water level of the wetland and the dissolved oxygen content, and the nitrification effect or the denitrification effect can be strengthened; and the cost of furnace slag packing is low.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a high-efficiency and low-cost combined subsurface flow artificial wetland system for treating polluted river water. The system is composed of a vertical subsurface flow wetland and a horizontal subsurface flow wetland. Background technique [0002] Constructed wetlands are man-made, controllable and engineered wetland systems. It is designed and constructed to treat sewage through an optimized combination of physical, chemical and biological actions in the wetland natural ecosystem. [0003] As a sewage treatment technology with large buffer capacity, simple process, low investment and low operating cost, constructed wetland has been widely used in the treatment of domestic sewage, rainfall runoff, polluted river and lake water, and domestic sewage after secondary or tertiary treatment. Low-concentration sewage and slightly polluted water such as low-concen...

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Problems solved by technology

[0006] (1) In the free surface artificial wetland, the sewage flows through the surface of the matrix, and the removal of pollutants by the biofilm and plant roots on the matrix filler cannot be used, so the removal rate of organic matter and nitrogen and phosphorus is not high

[0007] (2) Constructed wetlands with horizontal subsurface flow are often operated in the state of continuous flow and complete flooding, with poor oxygen transmission capacity and low dissolved oxygen content in the water inside the wetlands

When dealing with heavily polluted river water, the removal rate of ammonia nitrogen and total nitrogen in the horizontal subsurface flow constructed wetland alone is low; especially because the nitrification ability is weak and the denitrification ability is strong, when the concentration of ammonia nitrogen in the river water is high, it is not conducive to the total nitrogen removal rate. Efficient removal of nitrogen

[0008] (3) The vertical subsurface flow constructed wetland generally adopts the alternate operation mode of flooding and falling. Compared with the horizontal subsurface flow constructed wetland, it has a higher oxygen transmission capacity, and the content of dissolved oxygen in the wetland is higher, so the nitrification capacity is stronger, but The denitrification ability is poor, which affects the removal effect of total nitrogen

Although some researchers have developed different forms of composite constructed wetlands and combined constructed wetlands, no one has developed a combined subsurface flow constructed wetland system specifically for the characteristics of my country's polluted river water.

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