Double-layer subsurface-flow constructed wetland system used for sewage treatment in medium and small towns of cold areas and operation method thereof

Abstract

The invention relates to a double-layer subsurface-flow constructed wetland system used for sewage treatment in medium and small towns of cold areas and belongs to the field of sewage treatment engineering. The constructed wetland system comprises a water distribution regulating tank at one side of a tank body, an outlet water collecting tank at the other side of the tank body, an upper-layer wetland and a lower-layer wetland in the tank body, a water distribution pipe supplying water for the upper- / lower-layer wetlands, and an outlet water collecting pipe after treatment, wherein the upper-layer wetland and the lower-layer wetland are both subsurface-flow constructed wetlands and are separated by a waterproof interlayer, the lower part of the upper-layer wetland is filled with the composite filler of ceramsite and coal cinder, the upper part of the upper-layer wetland is filled with the composite filler of ceramsite, coal cinder and soil, aquatic plants are planted on the surface of the composite filler of the ceramsite, the coal cinder and the soil, the lower-layer wetland is filled with the composite filler of gravel and volcanic, the upper-layer constructed wetland is operated in summer, and the lower-layer constructed wetland is operated in winter, so that the double-layer subsurface-flow constructed wetland system is enabled to be operated stably all year round at an icebound period in northeast alpine areas, the investment and operation cost is low, the outlet water of the whole system meets the standard of first class B of GB18918-2002, and the system is particularly suitable for disperse sewage treatment in small towns with weak economic basis in cold areas.

Description

technical field [0001] The invention relates to a domestic sewage treatment system and use method, belonging to the field of sewage treatment engineering. Background technique [0002] The use of constructed wetland systems to treat domestic sewage has developed rapidly in recent years. The constructed wetland system is a complete ecosystem, which is mainly composed of four basic elements: substrate, vegetation, microorganisms, and water body, and each component works synergistically. The principle of purification is that the artificial wetland integrates the functions of biology, physics and chemistry in the process of treating wastewater. Ingestion and microbial decomposition to achieve efficient purification of sewage. There are a large number of microorganisms on the surface of the wetland filler and in the root system of the plant, forming a biofilm. When the wastewater flows through the wetland, the suspended matter is blocked by the filler and the root system, and t...

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Problems solved by technology

This method uses double-layer vertical flow wetlands to operate simultaneously to treat sewage. The sewage first flows through the upper aerobic zone and then enters the lower anaerobic zone, which strengthens the effect of nitrogen and phosphorus removal of sewage, and is suitable for the depth of nitrogen and phosphorus pollutants in ordinary domestic sewage. However, there is no anti-freezing structure design in this process, and it can only be used for sewage treatment in the non-freezing period in the southern or northern regions. However, the urban sewage treatment in the alpine regions of Northeast my country has the characteristics of a long freezing period. The traditional artificial There is winter freezing in wetlands, and the current existing technologies cannot meet the winter operation requirements in these areas

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