Multistage soil infiltration system for rural sewage treatment

Abstract

The invention provides a multistage soil infiltration system for rural sewage treatment, and relates to the technical field of sewage treatment. The invention discloses a multistage soil infiltration system for rural sewage treatment. The multistage soil infiltration system comprises a water inlet layer, a water distribution layer, an infiltration layer and a water outlet layer which are arranged from top to bottom, wherein the percolation layer comprises water-permeable zeolite layers and multiple layers of mixed soil blocks arranged between the water-permeable zeolite layers. Wherein the mixed soil block is prepared by the following method: mixing purple soil with activated aluminum oxide and iron powder, and then preparing the mixed soil block. According to the invention, the multi-step mixed soil blocks are adopted, so that the time of contact with sewage is further prolonged on the basis of reducing the use of materials, and the removal capacity of pollutants can be improved; activated aluminum oxide is adopted as a carrier in the percolation layer, so that the inhibition of pollutants such as antibiotics on the denitrification effect of the system can be reduced. In conclusion, the multi-stage soil percolation system provided by the invention strengthens the capability of removing new pollutants such as antibiotics.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and in particular relates to a multi-stage soil infiltration system for rural sewage treatment. BACKGROUND

[0002] In recent years, the source of rural domestic sewage is increasingly complex, including not only traditional kitchen washing, toilet flushing and other domestic wastewater, but also livestock and poultry breeding wastewater, sewage generated by rural tourism, etc. These sewage has the characteristics of dispersed discharge, large water fluctuation, and complex water quality composition.

[0003] To address the problem of rural sewage treatment, a variety of sewage treatment technologies have been developed and applied at home and abroad. Traditional activated sludge method, biological membrane method and other urban sewage treatment processes have good treatment effect, but have problems such as high construction cost, complex operation and management, high energy consumption, etc., and are difficult to be widely applied in rural areas. In view of the characteristics of rural areas, some technologies suitable for decentralized sewage treatment have emerged, such as ecological treatment technologies such as constructed wetlands and stabilization ponds. Constructed wetlands use the synergistic effect of soil, plants and microorganisms to purify sewage, and have the advantages of low investment, low operation cost and simple maintenance, but have the disadvantages of large land occupation and obvious seasonal and climatic influence on treatment efficiency, which limits their application in areas with limited land resources or cold winter. Stabilization ponds rely on natural biological purification function to treat sewage, but have the disadvantages of long hydraulic retention time, easy breeding of mosquitoes and flies, and generation of odor, which may cause secondary pollution to the surrounding environment. In addition, some simple septic tanks, biogas tanks and other treatment facilities have limited treatment effect and are difficult to meet the increasingly stringent sewage discharge standards. SUMMARY

[0004] The purpose of the present application is to solve the problem of rural domestic sewage treatment, especially the key common problem of scattered points, large water fluctuation and difficult operation and maintenance. The present application provides a multi-stage soil infiltration system for rural domestic sewage treatment, which utilizes the synergistic effect of adsorption and microorganisms to purify sewage, and has the advantages of green environmental protection, low treatment cost and convenient maintenance and use.

[0005] The purpose of the present application is achieved by the following technical solutions: A multi-stage soil infiltration system for rural sewage treatment, comprising a water inlet layer, a water distribution layer, a filtration layer and a water outlet layer arranged from top to bottom; wherein the filtration layer comprises a water-permeable zeolite layer and a plurality of mixed soil blocks arranged between the water-permeable zeolite layers.

[0006] In some embodiments of the present application, the thickness ratio of the water inlet layer, the water distribution layer, the filtration layer and the water outlet layer is 1:(2-3):(20-25):(2-3). In some embodiments of the present application, the water-permeable zeolite layer is made of zeolite with particle sizes of 1-3 mm and 3-5 mm, and the two kinds of zeolite are graded in a mass ratio of 1:1.

[0007] In some embodiments of the present application, the mixed soil blocks are staggered in the infiltration layer, and the number of layers of the mixed soil blocks is 3-4.

[0008] In some embodiments of the present application, the mixed soil blocks are prepared by mixing the purple soil with active aluminum oxide and iron powder, and then forming the mixed soil blocks.

[0009] In some embodiments of the present application, the longitudinal section of the mixed soil block is a symmetric multi-stage ladder shape with low in the middle and high on both sides.

[0010] In some embodiments of the present application, the mass ratio of the purple soil, the active aluminum oxide and the iron powder is 100:(20-30):(5-8); the particle size of the active aluminum oxide is 3-5 mm, and the active aluminum oxide is used as a carrier for microorganisms in the present application, so the particle size of the active aluminum oxide has a great influence on the system, and the active aluminum oxide with the particle size in the range has better effect.

[0011] In some embodiments of the present application, the water inlet layer is a grid shape, and the size of the grid is 5 cm*5 cm*5 cm, and green plants are planted in the grid.

[0012] In some embodiments of the present application, the water distribution layer is made of pebbles with particle sizes of 2-5 cm and 5-8 cm, and the two kinds of pebbles are graded in a mass ratio of 2:1.

[0013] In some embodiments of the present application, the water outlet layer is made of pebbles with particle sizes of 2-5 cm and 5-8 cm, and the two kinds of pebbles are graded in a mass ratio of 2:1.

[0014] The beneficial effects of the present application are: 1. The multi-stage ladder type mixed soil block is used in the present application, and the similar funnel-shaped mixed soil block forms a water storage area in the center, and the water stored inside can only be infiltrated; the square soil block in the prior art has small surface resistance, and sewage is more likely to run on the surface to reduce the effect of infiltration, so the multi-stage ladder type mixed soil block can further increase the contact time with sewage on the basis of reducing the use of materials, and the removal capacity of pollutants can be improved. 2. The active aluminum oxide is used as a carrier in the infiltration layer in the present application, which can effectively weaken the adsorption and aggregation of antibiotics on the surface of the carrier, and reduce the inhibition of the system microorganism denitrification under antibiotic stress.

[0015] In summary, the multi-stage soil infiltration system of the present application improves and enhances the removal capacity of new pollutants such as antibiotics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the multi-stage soil infiltration system of this application.

[0017] Figure 2 It is a schematic diagram of the front view and side view of the mixed soil block of this application. DETAILED DESCRIPTION

[0018] The following non-limiting examples illustrate the present invention.

[0019] Example 1: This embodiment provides a multi-stage soil infiltration system (MSL system) for rural sewage treatment, including an inlet layer, a water distribution layer, a percolation layer and an outlet layer arranged from top to bottom. Figure 1 shown.

[0020] Among them, the height of the water inlet layer is 5cm, and it is in a grid shape with a grid specification of 5cm×5cm×5cm. Green plants can also be planted in the grid to decorate the water inlet layer, and the elements in the sewage can provide for plant growth.

[0021] The thickness of the water distribution layer is 15 cm, and it is made of pebbles with particle sizes of 2-5 cm and 5-8 cm, graded according to a mass ratio of 2:1.

[0022] The percolation layer includes a permeable zeolite layer and multiple layers of mixed soil blocks arranged between the permeable zeolite layers. The permeable zeolite layer is made of zeolite with particle sizes of 1-3mm and 3-5mm, graded in a mass ratio of 1:1. The front view and side view of the mixed soil block are as follows Figure 2 As shown, its longitudinal cross-section is symmetrical, with a low center and high sides, forming a multi-step pattern. The height of the sides is 12 cm, and the height of the lowest point in the center is 3 cm. The mixed soil blocks are staggered in the infiltration layer, with four layers. In this embodiment, the mixed soil blocks are prepared by mixing 1000 g of purple soil with 250 g of activated alumina (particle size 3-5 mm) and 60 g of iron powder, and then forming the mixed soil blocks into a specific shape.

[0023] The outlet layer is made of pebbles with particle sizes of 2-5cm and 5-8cm, which are graded according to the mass ratio of 2:1.

[0024] The multi-stage soil filtration system (MSL system) was tested on site in a county in Mianyang City. The pollutant components were prepared by simulating the use of drugs. The sewage entered the MSL system from the water distribution layer at the top of the MSL system through a peristaltic pump and flowed to the outlet bucket through the outlet silicone hose. During the biofilm formation stage (15 days), the hydraulic load was set at 400L / (m 2• d), in the 11th, 13th, 15th d to sewage additional copper sulfate, manganese sulfate and ferrous sulfate, to ensure that the microbial nutrients sufficient. In and out of water indicators as shown in Table 1.

[0025] Table 1 Main changes in water quality

[0026] Example 2: The implementation and test method of this embodiment is basically the same as that of Example 1, the difference is that the composition of the mixed soil block used is different, which is composed of purple soil, 3-5mm particle size biochar and iron powder. The same method as Example 1 is used to carry out field experiments, and the in and out of water indicators are shown in Table 2.

[0027] Table 2 Main changes in water quality

[0028] Example 3: The implementation and test method of this embodiment is basically the same as that of Example 1, the difference is that the composition of the simulated wastewater is different. The in and out of water indicators are shown in Table 3.

[0029] Table 3 Main changes in water quality

[0030] Example 4: The implementation and test method of this embodiment is basically the same as that of Example 2, the difference is that the composition of the simulated wastewater is different. The in and out of water indicators are shown in Table 4.

[0031] Table 4 Main changes in water quality

[0032] Through Examples 1-2, it can be known that adding biochar or activated alumina in the mixed soil block can ensure that the system can remove conventional pollutants in wastewater, and the effect of adding biochar is slightly better than that of adding activated alumina; Through Examples 1, 3 and 4, it can be known that under the stress of antibiotics (sulfamethoxazole), the nitrification and denitrification performance of the MSL system is inhibited, and the MSL system with added biochar in the mixed soil block is more affected than the MSL system with added activated alumina.

[0033] The foregoing basic examples and each further selected example of the present application can be freely combined to form a plurality of embodiments, all of which are embodiments that can be used and claimed by the present application. In the present application scheme, each selected example can be arbitrarily combined with any basic example and selected example.

[0034] The above merely describes preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A multi-stage soil infiltration system for rural sewage treatment, characterized in that: It comprises a water inlet layer, a water distribution layer, a percolation layer and a water outlet layer arranged from top to bottom; wherein the percolation layer comprises a permeable zeolite layer and multiple layers of mixed soil blocks arranged between the permeable zeolite layers.

2. A multi-stage soil infiltration system for rural sewage treatment according to claim 1, characterized in that: The thickness ratio of the water inlet layer, the water distribution layer, the percolation layer and the water outlet layer is 1:(2-3):(20-25):(2-3).

3. The multi-stage soil infiltration system for rural sewage treatment according to claim 1, characterized in that: The permeable zeolite layer is made of zeolites with particle sizes of 1-3 mm and 3-5 mm, which are graded according to a mass ratio of 1:

1.

4. The multi-stage soil infiltration system for rural sewage treatment according to claim 1, characterized in that: The mixed soil blocks are staggered in the infiltration layer, and the number of layers of the mixed soil blocks is 3-4.

5. A multi-stage soil infiltration system for rural sewage treatment according to claim 4, characterized in that: The mixed soil block is prepared by the following method: purple soil is mixed with activated alumina and iron powder, and then made into the mixed soil block.

6. A multi-stage soil infiltration system for rural sewage treatment according to claim 5, characterized in that: The longitudinal cross section of the mixed soil block is low in the middle and high on both sides and is symmetrically multi-stepped.

7. The multi-stage soil infiltration system for rural sewage treatment according to claim 5, characterized in that: The mass ratio of the purple soil, activated alumina and iron powder is 100:(20-30):(5-8); the particle size of the activated alumina is 3-5 mm.

8. The multi-stage soil infiltration system for rural sewage treatment according to claim 1, characterized in that: The water inlet layer is in a grid shape, the size of the grid is 5cm×5cm×5cm, and green plants are planted in the grid.

9. The multi-stage soil infiltration system for rural sewage treatment according to claim 1, characterized in that: The water distribution layer is made of pebbles with particle sizes of 2-5 cm and 5-8 cm, which are graded according to a mass ratio of 2:

1.

10. The multi-stage soil infiltration system for rural sewage treatment according to claim 1, characterized in that: The water outlet layer is made of pebbles with particle sizes of 2-5 cm and 5-8 cm, which are graded according to a mass ratio of 2:1.

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