Construction method of local U-shaped underflow wetland for utilizing multi-phenological plants to enhance agricultural runoff denitrification

Abstract

The invention discloses a construction method of a local U-shaped underflow wetland for utilizing multi-phenological plants to enhance agricultural runoff denitrification and belongs to the technicalfield of sewage treatment. The method aims to solve the problems in existing low-carbon-nitrogen-ratio agricultural runoff underflow wetland treatment technologies that the addition of carbon sourcesis difficult to control, the cost of carbon supply fillers is high, wetland treatment systems are complex and large in occupied area, and the denitrification effect is influenced by nonuniform distribution of carbon sources of wetland plants. According to the method, in the construction process of the underflow wetland, a plurality of U-shaped depressions different in size and depth are constructed in a mode of loading fillers or not loading the fillers. A plurality of phenological perishable submerged plants and floating plants are arranged in the depressions, and a plurality of phenologicalemergent aquatic plants are arranged on the surface of the wetland, so that the plants in the wetland have different phenological configuration characteristics in different levels, and the uniform distribution of plant carbon sources in the wetland is enhanced. The constructed wetland has the advantages of adjusting the carbon-nitrogen ratio of agricultural runoff, consuming few fillers and beinghigh in denitrification efficiency and resistant to hydraulic impact.

Description

[0001] Technical field [0002] The invention relates to a local U-shaped subsurface flow wetland construction method using multi-phenological plants to strengthen agricultural runoff denitrification, and belongs to the technical field of sewage treatment. Background technique [0003] Agricultural runoff is mainly formed by rainfall scouring farmland, and its nitrogen content is high, which is one of the important sources of non-point source pollution. In order to intercept and treat pollutants, agricultural runoff is usually collected into constructed wetland systems, especially subsurface wetlands, for treatment. For nitrogen in runoff, the denitrification pathways of subsurface constructed wetlands mainly include microbial nitrification / denitrification, plant uptake, and substrate adsorption, among which nitrification / denitrification is the most important, and nitrogen removed through this pathway Generally, it accounts for more than 70% of the total nitrogen removal. Ho...

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Problems solved by technology

[0005] The purpose of the present invention is to improve the denitrification effect of agricultural runoff underflow wetland treatment with low carbon-to-nitrogen ratio, aiming to solve the problems in the prior art that the addition of carbon sources is difficult to control, the cost of carbon supply filler is high, and the treatment wetland system is complex and occupies a relatively small area. The uneven carbon source distribution of large and wetland plants affects the denitrification effect

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