Low-permeability substrate and application of substrate in construction of artificial wetland

Abstract

The invention discloses a low-permeability substrate and application of the substrate in construction of an artificial wetland. The low-permeability substrate comprises the following fillers with the particle sizes: the filler of which the particle sizes are smaller than 0.075mm, the filler of which the particle sizes are 0.075mm-0.6mm, the filler of which the particle sizes are 0.6mm-2mm, the filler of which the particle sizes are 2mm-6mm, and the filler of which the particle sizes are 6mm-10mm. According to the low-permeability substrate, the obtained filler has more uniform physical and chemical properties through multiple cleaning, screening, mixing and proportioning of a traditional artificial wetland filler, the uniformity coefficient is controlled to below 5, the porosity is controlled to be 30%-40%, the permeability is controlled to be 1.5*10<-4>m/s to 1.5*10<-3>m/s, the mean specific surface area of the filler reaches over 5,000-12,000m<2>/m<3> and is 15-20 times that of the traditional filler, so that the growth of microorganisms on the filler is promoted, the contact of the microorganisms and sewage is more uniform and sufficient, the synergistic effect of filler-plant-microorganisms is developed to the maximum extent, and the uniform treatment effect is achieved to solve the problems of treatment efficiency declination and blockage of the artificial wetland during long-term operation.

Description

technical field [0001] The invention belongs to the technical field of artificial wetlands, and in particular relates to a low-permeability matrix and its application in constructing artificial wetlands. Background technique [0002] The constructed wetland matrix supports the life process of animals, plants and microorganisms in the constructed wetland, creates good conditions for the successful interception of pollutants and subsequent plant absorption, and is an important guarantee for the quality of effluent water. In the process of sewage treatment in constructed wetlands, the pollutants entering the constructed wetlands are removed or retained under the synergistic effect of filler-plant-microbes. Transformed into other forms or microbial tissues remained in the pores of the filler under the action of the action, and some were absorbed by wetland plants. [0003] Since most of the artificial wetland fillers are made from local materials (fine sand, gravel, clay, etc.)...

AI Technical Summary

Problems solved by technology

[0003] Since most of the artificial wetland fillers are made from local materials (fine sand, gravel, clay, etc.), a single raw material is generally used, and there is no effective cleaning, screening and proportioning of the fillers, so the physical and chemical properties of the fillers vary greatly. Small specific surface area and uneven pore distribution

Such filler characteristics lead to poor extensibility of plant roots, poor microbial film growth, small specific surface area, and correspondingly low pollutant removal efficiency.

At the same time, due to the uneven contact between the microorganisms in the filler and the sewage, the local reaction efficiency is uneven, and the removal efficiency of pollutants in the sewage in the constructed wetland is inconsistent.

With the operation of the constructed wetland, the pollutants trapped in the pores continue to accumulate and occupy the pores of the filler, resulting in partial blockage of the constructed wetland, and the sewage treatment efficiency further decreases with the increase of operation time

In order to make the effluent water quality meet the specified standards, most constructed wetlands increase the treatment efficiency by increasing the area, and also need to replace the filler every two or three years, resulting in a waste of resources and an increase in investment costs

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