CN110683713A - Ecological treatment system for rural decentralized kitchen sewage - Google Patents

Abstract

The invention discloses an ecological treatment system for rural distributed kitchen sewage, which is composed of a matrix strengthening treatment system and a wetland absorbing system. The matrix strengthening treatment system includes a sedimentation tank and a plurality of biological matrix treatment units which are connected in series through communicating pipes, and the biological matrix treatment units are filled with naturally degradable biological matrix fillers. The wetland absorption system consists of three or more ecological wetlands connected by pipelines. The invention constructs an ecological treatment system in which the sewage flows and communicates along the pipeline, and clarifies the technological parameters of the construction of the ecological treatment system, which mainly include the hydraulic retention time, the area coefficient of the matrix strengthening treatment system, the biological matrix input amount coefficient and the wetland absorption system. Area coefficient, etc., has strong operability and wide applicability. The invention has simple structure and convenient operation, and has good effect on the treatment of pollutants such as COD, nitrogen and phosphorus in kitchen sewage, especially the oil pollution of animals and plants, and is suitable for the treatment of scattered kitchen sewage in rural areas.

Description

An ecological treatment system for rural decentralized kitchen sewage

technical field

The invention relates to the technical field of sewage treatment, in particular to an ecological treatment system for rural distributed kitchen sewage.

Background technique

my country's agricultural and rural water pollution mainly comes from village life pollution, livestock and poultry breeding pollution, agricultural product processing pollution and farmland drainage. Compared with urban sewage treatment, the pollution sources of rural water environment are complex and widely distributed, and the cost of centralized sewage collection is too high. Therefore, decentralized sewage treatment methods are often used in rural areas with non-concentrated population. In particular, with the rise and development of modern tourism agriculture and leisure agriculture, there are more and more farmhouses and catering businesses, which not only increase the income of farmers, but also increase the discharge of kitchen waste and wastewater, aggravating the problem of rural environmental pollution.

The kitchen waste wastewater mainly comes from the water in the kitchen waste itself and the moisture generated during the fermentation process of the waste. The composition of the kitchen waste water is complex and the organic content is high, mainly including dietary fiber, starch, fat, animal and vegetable oils, various additives. ingredients, detergents, and proteins. Because the fatty acids decomposed by the high-temperature hydrolysis of the kitchen waste are not further degraded, the COD mass concentration of the generated wastewater increases, and the solids of the kitchen waste are rich in protein, and the protein is ammoniated during the digestion process, causing the kitchen waste. The waste water has high concentrations of ammonia nitrogen and total nitrogen, resulting in a low carbon-nitrogen ratio, which not only affects anaerobic digestion, but also affects the subsequent biochemical treatment of wastewater. Due to the inhibitory effect of high ammonia nitrogen, biochemical treatment is difficult.

At present, subsurface wetlands and surface wetlands (including ecological ditches) are mostly used in rural decentralized sewage treatment, and they are also relatively successful ecological sewage treatment technologies. For example, invention patent CN201210426016.X discloses a combined urban sewage treatment constructed wetland system and urban sewage treatment method. The system includes biological regulation pool units, aerobic degradation and microbial culture pools, subsurface wetlands, and surface wetlands in series. The substrates in the subsurface wetlands are, from bottom to top, a gravel layer, a fine sand layer, and a mixed layer of vermiculite and fine sand. , mixed layer of fine sand and red soil, the surface wetland is equipped with various emergent, floating leaf, floating and submerged aquatic plants from shallow to deep. However, in the above method, the subsurface wetland uses porous media materials such as gravel and fine sand as the percolation layer, and the adsorption performance of the percolation layer to pollutants will decrease with the increase of the wetland operating time, which will eventually lead to the complete failure of the entire system and increase the cost; at the same time, Sewage contains high content of kitchen sewage oil, which degrades slowly and floats on the surface of sewage. After sewage oil enters surface wetland, it will adhere to the leaf surface or stem of wetland plants, which can easily lead to plant death; There is a lack of unified technical specifications for wetland design and construction, which leads to a lot of randomness in the setting of process parameters in actual engineering construction. Invention patent CN201910361153.1 discloses a combined A/A/O and MAP treatment method for kitchen wastewater, including the following steps: (1) adjusting the pH of the wastewater to pH=6.8-7.5; (2) adjusting the pH of the wastewater The wastewater enters the A/A/O system. The A/A/O system includes anaerobic fermentation tank, anoxic tank, aerobic tank and secondary sedimentation tank, so that the wastewater enters the anaerobic fermentation tank, anoxic tank and aerobic tank in turn. and the secondary sedimentation tank; (3) make the sediment in the anaerobic fermentation tank and the sludge in step (2) enter the MAP system; (4) add a flocculant to the MAP reaction tank; (5) make it processed in step (4) The product of MAP enters the MAP sedimentation tank and is left to stand until the supernatant and the sediment are clearly stratified, but the kitchen sewage oil content is high and floats on the surface of the sewage, which is not easy to be degraded and removed by anaerobic bacteria or anoxic bacteria. Therefore, this makes it difficult to effectively treat rural kitchen sewage by the currently commonly used "anaerobic fermentation tank/underwater wetland".

SUMMARY OF THE INVENTION

In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide an ecological treatment system for rural distributed kitchen sewage, which solves the problems of poor treatment effect and high cost of animal and vegetable oil pollution in kitchen sewage in the existing method. question.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical scheme: including a matrix strengthening treatment system and a wetland absorption system, and the matrix strengthening treatment system includes a sedimentation tank and a plurality of biological matrix treatment systems that are connected in series through a communication pipeline. unit, the sedimentation tank is connected with the kitchen sewage discharge pipeline, the biological matrix treatment unit is provided with a naturally degradable biological matrix filler, and the matrix strengthening treatment system is connected to the wetland consumption system through the communication pipeline, and the wetland consumption The system consists of more than three ecological wetlands connected by pipelines, and the upper part of the wetland absorption system is planted with vegetation.

The sedimentation tank is the primary site for sedimentation and anaerobic treatment of kitchen sewage, and the biological matrix treatment unit is the secondary site for biological matrix delivery and adsorption and decomposition of sewage pollutants. The matrix strengthening treatment system generally consists of a sedimentation tank or more than two biological matrix treatment units.

Preferably, both the sedimentation tank and the biological matrix treatment unit in the matrix strengthening treatment system are regular closed tanks, and the bottom and surrounding walls of the tank need to be hardened and impermeable to prevent sewage from seeping out; the top is hardened and sealed, but retains a diameter A working wellhead of about 60cm is used for sediment removal or biomatrix packing during system maintenance. During the operation of the system, each wellhead is closed with a well cover.

As preferably, a plurality of sockets are provided on the pond wall of the biological matrix processing unit, the sockets are uniformly distributed in a rectangular array, and the sockets on the corresponding pond wall are correspondingly arranged, and a blocking rod is provided between the corresponding sockets. In this way, the biological matrix filler is distributed on multiple water layers, and the adsorption of the biological matrix filler to pollutants such as nitrogen, phosphorus, animal and vegetable oil pollution in sewage is enhanced.

The two adjacent sockets are spaced 1.0-1.5m in the horizontal direction, and the two adjacent sockets are spaced in the vertical direction

0.2～0.8m.

Preferably, the biological matrix treatment unit and the water inlet of the ecological wetland are arranged at the bottom of one side wall, and the water outlet is arranged at the top of the other side wall, so that the water outlet and inlet of the biological matrix treatment unit and the ecological wetland are arranged. The nozzles are arranged diagonally. In this way, the kitchen sewage enters from the bottom and is discharged from the diagonal top, and the path is long, which makes the adsorption of nitrogen, phosphorus, animal and vegetable oil pollution and other pollutants in the sewage more thorough and efficient.

Preferably, the total area of the matrix strengthening treatment system is determined according to the following formula (1):

S _A =N*V _s *D/H _s (1)

In the formula, S _A is the total construction area of the matrix intensified treatment system (m ² ); N is the daily maximum number of diners; Vs is the volume coefficient of the matrix intensified treatment system of a single tourist, ranging from 0.1 to 0.25 m ³ ; Residence time in the matrix-enhanced treatment system; Hs is the highest water level in the matrix-enhanced treatment system. In actual construction, the volume coefficient of the matrix strengthening treatment system can be flexibly adjusted according to the actual situation. If the land area is sufficient, the coefficient can be appropriately increased. The overall principle is to keep the hydraulic retention time of sewage in the matrix enhanced treatment system not less than 7d. Preferably, the construction area ratio of the sedimentation tank and the biological matrix treatment unit is 1:4.

Preferably, the biological matrix filler is one or more materials selected from straw, wheat straw and corn stalk. Preferably, after the above-mentioned biological matrix filler is expanded, the porosity of cellulose in the biological matrix is increased, the surface groups of cellulose are exposed, and its adsorption capacity and adsorption capacity are improved. Preferably, corn stalk needs to be shredded (particle size < 5mm) and used in combination with a certain amount of straw or wheat straw. The ratio of cornstalk to straw/wheat straw was 2:3.

Preferably, the dosage of the biological matrix filler is determined according to the following formula (2):

W=V*P _s (2)

In the formula, W is the total amount of fillers put into the biological matrix treatment unit (kg); V is the total volume of the matrix strengthening treatment system; P _s is the dosage coefficient of biological matrix fillers per unit volume of sewage, which ranges from 20 to 30Kg/m ³ . Considering that the decomposition time of straw filler is 3 to 4 months, the frequency of feeding straw filler is 3 times per year, and the total amount of each feeding is 1/3 (W/3) of the total amount.

Preferably, the total area of the wetland absorption system is determined according to the following formula (3):

Sp ₌ N*P _A (3)

In the formula, Sp is the total area of the wetland absorption system (m ² ), N is the daily maximum number of diners; _{P A} is the wetland construction area coefficient of a single dining visitor, ranging from 1 to 2.5m ² . The water depth of the ecological wetland is maintained at about 1.5-2.5m. In actual construction, it is required to flexibly adjust the water depth of the wetland under the condition that the hydraulic retention of the wetland absorption system is not less than 14 days.

Preferably, the configuration of aquatic plants in the multi-level wetlands is in turn of large emergent plants, small emergent plants and floating plants, and the corresponding planting area configuration ratio is 3:3:4. By arranging high-medium-low three kinds of aquatic plants in the multi-level wetland along the sewage flow direction, it is beneficial to promote the adsorption and degradation of residual oil pollution entering the wetland.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention aims at the characteristics of dispersibility, high organic matter concentration and high oil content in the rural kitchen sewage, and the proposed ecological treatment system for the rural distributed kitchen sewage is a coupling process of the matrix strengthening treatment system and the wetland absorption system. , Replace the traditional anaerobic fermentation / submerged wetland technology with the technology combination of matrix strengthening treatment + wetland absorption, and effectively absorb and degrade nitrogen in kitchen sewage by putting in naturally degradable biological matrix materials and the reasonable configuration of different wetland plants. Phosphorus, oil pollution and other organic pollutants can efficiently treat rural scattered kitchen sewage; it not only solves the problem of the removal and degradation of dirty oil in kitchen sewage, but also overcomes the weakness of traditional subsurface wetlands that require regular excavation and replacement of adsorption materials. In addition, according to the characteristics of rural dispersed kitchen sewage, the present invention clarifies the process parameters for the construction of the matrix strengthening treatment system and the wetland absorption system, such as the hydraulic retention time of 14d and the volume coefficient of the matrix strengthening treatment system being 0.1-0.25m ³ / The input coefficient of human and biological substrate is 20～30Kg/m ³ and the coefficient of wetland area is 1～2.5m ² /person, etc., which significantly improves the sewage treatment effect, and has strong operability and good popularization and application.

2. The present invention uses natural biological matrix materials (rice straw, wheat straw and corn stalk) as raw materials, which are rich in sources and low in price, and are renewable and environmentally friendly natural materials, and the natural biological matrix materials can be directly decomposed in the treatment process, No post-processing is required, thereby increasing the treatment and utilization approaches of straw, wheat straw, corn stalk and other bulk crop straw waste, avoiding environmental pollution, and having a good application prospect.

3. The structure of the present invention is simple, the operation is convenient, and the wetland absorption system can be formed by one or more field drainage ditches, natural or newly excavated pits, and is suitable for the characteristics of rural dispersion, durability and good treatment effect. It has strong practicability and wide applicability.

Description of drawings

FIG. 1 is a schematic structural diagram of the present invention for a rural decentralized kitchen sewage treatment system.

Detailed ways

The present invention will be further described in detail below in conjunction with the examples.

An embodiment of the present invention provides a rural decentralized kitchen sewage treatment system, as shown in FIG. 1 , its structural schematic diagram includes a matrix strengthening treatment system and a wetland storage system, and the matrix strengthening treatment system A sedimentation tank and 3 biological matrix treatment units connected in series at the beginning and end, the sedimentation tank is connected with the kitchen sewage discharge pipeline, the biological matrix treatment unit is provided with a naturally degradable biological matrix filler, and the sedimentation tank and biological matrix treatment The bottom and side walls of the unit are both impermeable structures, the matrix strengthening treatment system is connected to the wetland absorption system through a communication pipeline, and the wetland absorption system includes three ecological wetlands connected in sequence through the communication pipeline.

The principle and effect of the above-mentioned technical scheme are: through the system, the insoluble substances in the sewage are precipitated and anaerobic treated by precipitation treatment. Then through multiple biological matrix treatment units to absorb and degrade nitrogen, phosphorus and dirty oil in the sewage, and finally through the wetland absorption system to further absorb and absorb the pollutants in the sewage. Vegetable oil pollution, complete the ecological treatment of kitchen sewage.

Example

This example comes from a farmhouse sewage treatment site in Zhejiang. The farmhouse receives about 100 dining tourists at peak times. Before the construction of the sewage treatment facility, the farmhouse's kitchen sewage mixed with domestic sewage was not treated, and was directly discharged into the environment through the sewers, causing great pollution to the surrounding water environment. Due to the lack of available ditches and natural pits in the surrounding area, the sewage treatment facility was newly constructed on abandoned land.

The treatment system for kitchen sewage includes a matrix-enhanced treatment system and a wetland storage system. The matrix-enhanced treatment system includes a settling tank and a plurality of biological matrix treatment units that are connected in series through communicating pipes. The sewage discharge pipeline is connected, the biological matrix treatment unit is filled with naturally degradable biological matrix filler, the bottom and side walls of the sedimentation tank and the biological matrix treatment unit are all impermeable structures, and the pond wall of the biological matrix treatment unit A plurality of sockets are arranged on the top, the sockets are evenly distributed in a rectangular array, and are correspondingly arranged corresponding to the sockets on the pool wall, and blocking rods are arranged between the corresponding sockets. The adjacent sockets are separated by 1.0m in the horizontal direction, and the adjacent sockets are separated by 0.3m in the vertical direction. The matrix strengthening treatment system is connected with the wetland absorption system through the communication pipeline, and the wetland absorption system includes the first-level ecological wetland, the second-level ecological wetland and the third-level ecological wetland connected in sequence through the communication pipeline, and the wetland absorption system is Vegetation is planted on the upper part, and the tertiary ecological wetland is connected with a water purification pool, and the water purification pool outputs the water body in the purification pool through a water purification output pipeline.

1.1 Construction area of matrix strengthening treatment system

The formula for the total area of the matrix strengthening treatment system:

S _A =N*V _s *D/H _s (1)

In the formula, S _A is the total construction area of the matrix intensified treatment system (m ² ); N is the daily maximum number of diners; Vs is the volume coefficient of the matrix intensified treatment system of a single tourist, ranging from 0.1 to 0.25 m ³ ; Residence time in the matrix-enhanced treatment system; Hs is the highest water level in the matrix-enhanced treatment system.

Considering that the maximum number of _diners N is 100, the peak ^of sewage load is concentrated in the summer when the wetland plants grow vigorously, and the discharge is not high at other times. The residence time D was set to 7d, and the maximum water level Hs of the matrix pool was set to be 2.5m. According to formula (1), the construction area SA of the matrix strengthening treatment system is calculated to be _50.4m ² .

1.2 Area and construction requirements of sedimentation tank and biological matrix treatment unit

The sedimentation tank and each biological matrix treatment unit are connected by PVC pipes with a diameter of 5 cm. The kitchen sewage first flows into the sedimentation tank through the kitchen sewage discharge pipe, and then flows out of the biological matrix treatment unit in turn. And the water inlet of each pool is arranged at the bottom of one side wall, and the water outlet is arranged at the top of the other side wall, so that the water outlet and water inlet of each pool are arranged diagonally. The bottom and side walls of the sedimentation tank and the biological matrix tank are hardened with cement, and the top is hardened and sealed but a working wellhead with a diameter of 60 cm is left. During the operation of the project, the wellhead of each matrix pool is closed with a well cover.

Since the matrix strengthening treatment system consists of a sedimentation tank and three biological matrix treatment units in series, the area ratio of the sedimentation tank and the biological matrix treatment unit is set according to the area ratio of 1:4, that is, the area of the sedimentation tank is 10.1m ² ; The size of the three biological matrix treatment units is the same, and the unit area is about 13.4m ² .

1.3 Amount of biological matrix

The dosage formula of biological matrix:

W=V*P _s (2)

In the formula, W is the total amount of straw put in by the biological matrix treatment unit (kg); V is the total volume of the matrix enhanced treatment system; P _s is the straw putting coefficient per unit volume of sewage, which is 20-30Kg/m ³ .

In view of the fact that the sewage treatment project is located in the rice planting area and the straw is abundant, the biological matrix treatment unit selects the straw as the filler of the matrix pool. The unit volume sewage biological matrix input coefficient P _s is 25kg/m ³ , the total volume V of the matrix strengthening treatment system is 126m ³ (50.4m ² × 2.5m), and the total input amount of straw W is 3150kg calculated according to formula (2). Among them, the frequency of straw feeding is 3 times per year, and the amount of each feeding is 1/3 of the total amount, that is, 1050kg.

1.4 Parameters and construction requirements of wetland absorption system

The formula for the total area of the wetland absorption system:

Sp ₌ N*P _A (3)

In the formula, Sp is the total area of the wetland absorption system (m ² ), N is the daily maximum number of diners; _{P A} is the wetland construction area coefficient of a single dining visitor, ranging from 1 to 2.5m ² .

Considering that the maximum number of diners N is 100, the peak sewage load is concentrated in the summer when the wetland plants grow vigorously, and the discharge is not high at other times, the wetland construction area coefficient P _A is taken as 1 m ² . According to formula (3), the total construction area _Sp of ecological wetland is calculated as 100m ² .

The first-level ecological wetlands, the second-level ecological wetlands and the third-level ecological wetlands are arranged in series mode, connected by PVC pipes. The water inlet of each level of ecological wetland is set at the bottom of one side wall, and the water outlet is set at the top of the other side wall. , so that the water outlets and water inlets of the pools are arranged diagonally. The area ratio of the first-grade ecological wetland, the second-grade ecological wetland and the third-grade ecological wetland is 3:3:4, that is, the first-grade ecological wetland is 30m ² , the second-grade ecological wetland 30m ² , and the third-grade ecological wetland 40m ² .

1.5 Requirements for the configuration of ecological wetland plants

The upper parts of the first-class ecological wetland, the second-class ecological wetland and the third-class ecological wetland are planted with barracuda (large emergent plants), copper buckwheat (small emergent plants) and foxtail algae (floating plants). 8 strains/m ² of fish grass, 25 strains/m ² of Corydalis chinensis, and 6kg/m ² of stalks and leaves of Lexus chinensis.

The water quality of the sewage treatment effect of the farmhouse was monitored for a period of one year by the kitchen sewage treatment system of this embodiment, and the results are shown in Table 1.

Table 1

It can be seen from Table 1 that the average contents of pollutant indicators COD, total nitrogen, ammonia nitrogen, total phosphorus and animal and vegetable oils in the kitchen sewage influent are 114.9mg/L, 28.2mg/L, 24.8mg/L and 5.29mg, respectively. /L, 13.1mg/L, the contents of COD, total nitrogen, ammonia nitrogen and total phosphorus in the effluent after treatment were 11.8mg/L, 3.7mg/L, 2.91mg/L, 0.48mg/L, 1.13mg, respectively /L, the corresponding average removal rates of pollutants were 89.3%, 86.6%, 87.9%, 90.8%, and 91.3%, respectively. On the whole, the treatment effect of COD, total nitrogen, ammonia nitrogen and total phosphorus pollutants in the sewage of this example project has reached the national level 1 A standard for urban sewage discharge, and the treatment effect of animal and vegetable oil pollutants in the sewage has reached the national urban sewage discharge level 1 B. standard.

To sum up, the present invention has better removal effect on COD, total nitrogen and total phosphorus in kitchen sewage, especially better treatment effect on animal and plant sewage oil with higher content.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. an ecological treatment system for rural disperse kitchen sewage, is characterized in that, comprises matrix strengthening treatment system and wetland absorbing system, and described matrix strengthening treatment system comprises 1 sedimentation tank connected in series successively by communicating pipeline and a plurality of biological matrix treatment units, the sedimentation tank is communicated with the kitchen sewage discharge pipeline, the biological matrix treatment unit is filled with naturally degradable biological matrix fillers, and the matrix enhancement treatment system communicates with the wetland storage system through the communication pipeline. connected, the wetland absorbing system is composed of 3 or more ecological wetlands connected by pipelines, and aquatic plants are planted on the water surface of the ecological wetland; The total area of the matrix strengthening treatment system is determined according to the following formula (1): S _A =N*V _s *D/H _s (1) In the formula, S _A is the total construction area of the matrix intensified treatment system (m ² ); N is the daily maximum number of diners; Vs is the volume coefficient of the matrix intensified treatment system of a single tourist, ranging from 0.1 to 0.25 m ³ ; Residence time in the matrix intensification treatment system; Hs is the highest water level in the matrix intensification treatment system; The total area of the wetland absorption system is determined according to the following formula (3): Sp ₌ N*P _A (3) In the formula, Sp is the total area of the wetland absorption system (m ² ), N is the daily maximum number of diners; _{P A} is the wetland construction area coefficient of a single dining visitor, ranging from 1 to 2.5m ² . 2. The ecological treatment system for rural distributed kitchen sewage according to claim 1, wherein the biological matrix treatment unit and the water inlet of the ecological wetland are both arranged at the bottom of a side wall, and the water outlet is arranged at the bottom of a side wall. On the top of the other side wall, the water outlet and water inlet of the biological substrate treatment unit and the ecological wetland are arranged diagonally. 3. The ecological treatment system for rural distributed kitchen sewage according to claim 1, wherein a plurality of sockets are arranged on the pond wall of the biological matrix treatment unit, and the sockets are uniformly distributed in a rectangular array, The sockets on the corresponding pool wall are correspondingly arranged, and a blocking rod is arranged between the corresponding sockets. 4. The ecological treatment system for rural distributed kitchen sewage according to claim 3, wherein the interval between the adjacent sockets in the horizontal direction is 1.0-1.5m, and the interval between the adjacent sockets in the vertical direction is 1.0-1.5m. 0.2～0.8m. 5. The treatment system for rural dispersed kitchen sewage according to claim 1, wherein the sedimentation tank and the biological matrix treatment unit are both regular closed tank bodies, and the bottom of the tank body and the side walls are both. Impervious structure. 6 . The treatment system for rural distributed kitchen sewage according to claim 1 , wherein the ratio of the area of the sedimentation tank in the matrix strengthening treatment system to the total area of the biological matrix treatment unit is 1:4. 7 . 7 . The ecological treatment system for rural distributed kitchen sewage according to claim 1 , wherein the biological matrix filler is one or more mixed materials of straw, wheat straw and corn stalk. 8 . 8. The treatment system for rural dispersed kitchen sewage according to claim 1, wherein the dosage of the biological matrix filler is determined according to the following formula (2): W=V*P _s (2) In the formula, W is the total amount of fillers put into the biological matrix treatment unit (kg); V is the total volume of the matrix strengthening treatment system; P _s is the filling factor of sewage filler per unit volume, which is 20-30Kg/m ³ . 9. The ecological treatment system for rural distributed kitchen sewage according to claim 1, wherein the aquatic plants in the ecological wetland are sequentially configured as large emergent plants, small emergent plants and Floating plants. 10. The ecological treatment system for rural distributed kitchen sewage according to claim 1, wherein the planting area ratio of the large emergent plants, the small emergent plants and the floating plants is 3:3:4.