Highway sponge-type composite side ditch carbon neutralization system and method thereof

Abstract

The highway sponge-type composite side ditch carbon neutralization system of the present invention includes three units, i.e., a silt pre-sedimentation channel, a filtering and oil-absorbing channel and an ecologic purification channel which are connected horizontally and successively. These three units work together to jointly complete the low-impact development functions of runoff collection, guide and drainage, purification and utilization, carbon emission is reduced by adopting various technical measures, the carbon sink effect is improved, and the full-life-cycle carbon neutralization effect from raw material production, construction to operation can be realized.

Claims

1. A highway sponge-type composite side ditch carbon neutralization system, comprising three units, wherein the three units are a silt pre-sedimentation channel, a filtering and oil-absorbing channel, and an ecologic purification channel, wherein, the silt pre-sedimentation channel, the filtering and oil-absorbing channel, and the ecologic purification channel are connected horizontally and successively; road runoff enters the silt pre-sedimentation channel from an inlet ditch, flows into the filtering and oil-absorbing channel from the silt pre-sedimentation channel, consecutively flows into the ecological purification channel and flows out from an outlet ditch after being treated, wherein the silt pre-sedimentation channel comprises: a first water inlet and a first water outlet arranged at middle-upper parts of a first water inlet side and a first water outlet side of the silt pre-sedimentation channel respectively; a sand collecting bucket arranged at a first bottom portion towards the first water inlet side; and a sludge converging slope inclined at an angle from the first water outlet side towards the first water inlet side, wherein the sludge converging slope is arranged at a bottom plate of the silt pre-sedimentation channel; effluent water from the silt pre-sedimentation channel is received by the filtering and oil-absorbing channel through the first water outlet at a middle-upper part of a second water inlet side of the filtering and oil-absorbing channel wherein, the filtering and oil-absorbing channel further comprises: a second water outlet arranged at a bottom portion of a second water outlet side of the filtering and oil-absorbing channel; a second filtering layer comprising second filter materials; a first filtering layer comprising first filter materials; and an oil-absorbing fiber layer; and grating plates, wherein, the second filtering layer, the first filtering layer and the oil-absorbing fibre layer are arranged in the filtering and oil-absorbing channel from bottom to top; and the grating plates are arranged at a top of the second filtering layer and at a top of the first filtering layer, wherein the grating plates are configured to prevent filter materials from floating up and floating away; effluent water from the filtering and oil-absorbing channel is received by the ecologic purification channel through the second water outlet into a third water inlet at a bottom portion of a third water inlet side of the ecological purification channel, wherein the ecologic purification channel comprises: a modified volcanic rock layer; a sawdust layer; a modified ceramsite layer comprising modified ceramsites, wherein the modified ceramsite is formed by combined processing of zeolite, fly ash and calcium carbonate; a configured planting soil layer; carbon sink vegetation; and a third water outlet, wherein, the modified volcanic rock layer, the sawdust layer and the modified ceramsite layer are arranged successively in the ecologic purification channel from bottom to top; the sawdust layer is filled with sawdust, wherein each of the sawdust particle has a particle size of 30 mm and the sawdust layer is doped with microbial quick-dissolving balls at a volume ratio of 10%; the modified ceramsite layer is filled with modified ceramsites, wherein each of modified ceramsite has a particle size of 20 mm and the ceramsite layer is doped with microbial quick-dissolving balls at a volume ratio of 20%, wherein, each of the microbial quick-dissolving balls in the saw dust layer and the modified ceramsite layer are configured to be: internally filled with functional microorganisms for deep nitrogen and phosphorus removal; and externally packed with PVA that gradually dissolves in water to uniformly disperse the functional microorganisms filled within; and the third water outlet is arranged over the configured planting soil layer of the ecologic purification channel at a third water outlet side.

2. The highway sponge-type composite side ditch carbon neutralization system according to claim 1, wherein a deflection baffle is arranged upwards in a middle of the sludge converging slope, and the deflection baffle intersects with the sludge converging slope to form a sludge collecting tank.

3. The highway sponge-type composite side ditch carbon neutralization system according to claim 1, wherein, grid cover plates are arranged at top portions of the silt pre-sedimentation channel and the filtering and oil-absorbing channel; additional spaces are provided at an upper part of the silt pre-sedimentation channel and the filtering and oil-absorbing channel for a purpose of buffering a rainstorm runoff; and impermeable layers made of impermeable geotextiles are arranged on the bottom plate and side walls of the silt pre-sedimentation channel, the filtering and oil-absorbing channel, and the ecologic purification channel.

4. The highway sponge-type composite side ditch carbon neutralization system according to claim 1, wherein a valve is arranged at the first water outlet; and a barrier net is arranged at the second water outlet.

5. The highway sponge-type composite side ditch carbon neutralization system according to claim 1, wherein materials that is used for adsorption, filtration and for removing oil are selected as filter materials for the second filtering layer, the first filtering layer and the oil-absorbing fiber layer, in the filtering and oil-absorbing channel.

6. The highway sponge-type composite side ditch carbon neutralization system of claim 5, wherein the second filtering layer is filled with polyether sponge as a filter material; the first filtering layer is filled with the polyester sponge as the filter material; and the oil-absorbing fiber layer is filled with nano oil-absorbing material as the filter material.

7. The highway sponge-type composite side ditch carbon neutralization system according to claim 1, wherein, the modified volcanic rock layer in the ecologic purification channel is 40-70 cm high, filled with modified volcanic rocks with a particle size of 50 mm; the sawdust layer is 10-30 cm high; the modified ceramsite layer is 50-80 cm high; planting soil and yellow sand are used in the configured planting soil layer, and a volume ratio of the planting soil to the yellow sand is 70:30; vegetation with a carbon sink effect is used as the carbon sink vegetation.

8. The highway sponge-type composite side ditch carbon neutralization system according to claim 7, wherein the functional microorganisms in the microbial quick-dissolving balls are selected from a group consisting of bacillus, Rhodobacter and Exiguobacterium sp.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plane view of a highway sponge-type composite side ditch carbon neutralization system.

(2) FIG. 2 is a structural view of a silt pre-sedimentation channel.

(3) FIG. 3 is a structural view of a filtering and oil-absorbing channel.

(4) FIG. 4 is a structural view of an ecologic purification channel.

(5) TABLE-US-00002 1: Inlet ditch 2: Silt pre-sedimentation channel 3: Filtering and oil-absorbing channel 4: Ecologic purification channel 5: Outlet ditch 6: First water inlet 7: Sand collecting bucket 8: Deflection baffle 9: Sludge collecting tank 10: Sludge converging slope 11: First water outlet 12: Grid cover plate 13: Impermeable layer 14: Second water outlet 15: oil-absorbing fiber layer 16: First filtering layer 17: Second filtering layer 18: Modified volcanic rock layer 19: Sawdust layer 20: Modified ceramsite layer 21: Configured planting soil layer 22: Carbon sink vegetation 23: Third water outlet 24: Grating plate 25: Barrier net

DETAILED DESCRIPTION OF THE EMBODIMENTS

(6) In order to further elaborate the technical means adopted in the present invention to achieve the intended purpose of the present invention and the efficacy thereof, the specific implementation modes, steps, structure, characteristics and efficacy of the highway sponge-type composite side ditch carbon neutralization system provided on the basis of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

Example 1

(7) A highway sponge-type composite side ditch carbon neutralization system includes a silt pre-sedimentation channel, a filtering and oil-absorbing channel and an ecologic purification channel which are connected successively. Ordinary side ditches are arranged ahead of and behind the highway sponge-type composite side ditch carbon neutralization system and alternated with each other. Impermeable geotextiles (two fabrics and one membrane) are laid at the bottom and side walls of the highway sponge-type composite side ditch carbon neutralization system.

(8) Upstream longitudinal road runoff collected by the inlet ditch flows into the first water inlet at a middle-upper part of a water inlet side of the silt pre-sedimentation channel, and first-stage purification is performed in the silt pre-sedimentation channel under the action of deflection sedimentation. After purification, the upstream longitudinal road runoff flows out from the first water outlet at a middle-upper part of a water outlet side of the silt pre-sedimentation channel and enters from a middle-upper part of a water inlet side of the filtering and oil-absorbing channel. After second-stage purification processes such as adsorption by the oil-absorbing fiber in the upper layer and filtration by filter materials in middle and lower layers, the upstream longitudinal road runoff flows out from the second water outlet at the bottom of a water outlet side of the filtering and oil-absorbing channel and enters from the bottom of a water inlet side of the ecologic purification channel. After third-stage purification such as deep adsorption and filtration by the modified volcanic rocks, biodegradation by the sawdust layer and modified ceramsite layer, plant absorption and the like, the upstream longitudinal road runoff flows out from the third water outlet at an upper part of the water outlet side of the ecologic purification channel and flows into the outlet ditch. The transverse runoff in this highway section flows into the silt pre-sedimentation channel, filtering and oil-absorbing channel and ecologic purification channel respectively from top to bottom through the grid cover plates arranged at the top of the silt pre-sedimentation channel and of the filtering and oil-absorbing channel and the carbon sequestration vegetation and planting soil at the top of the ecologic purification channel.

(9) A first water inlet and a first water outlet are arranged at a two-thirds point (calculated from the bottom) of a total height of the silt pre-sedimentation channel, and a deflection baffle with a total height of one-second is arranged upwards at a one-third point (at the water inlet side) of a total length of the bottom. A sludge converging slope with an inclination angle of 3% is arranged towards the water inlet side at the bottom. A circular-hole cover plate of a steel concrete structure is arranged at the top of the silt pre-sedimentation channel to facilitate opening and cleaning. A valve is arranged at the first water outlet, so that hazardous chemicals and leakage liquid thereof are stored in the silt pre-sedimentation channel after the valve is closed in case of a leakage accident of hazardous chemicals, and then the hazardous chemicals and leakage liquid are pumped out and disposed by an environmental protection authority to avoid polluting surrounding water bodies and groundwater.

(10) A second filtering layer, a first filtering layer and an oil-absorbing fiber layer are arranged in the filtering and oil-absorbing channel from bottom to top, the heights of these three layers are 30%, 25% and 5% of the total height respectively, and the remaining 40% is an additional space for buffering during rainstorm. The second filtering layer is filled with polyether sponge as filter material, the first filtering layer is filled with polyester sponge as filter material, the oil-absorbing fiber layer is filled with nano oil-absorbing fiber as filter material, the polyether sponge is of a 10 mm10 mm mesoporous structure, and the polyester sponge is of a 20 mm20 mm macroporous structure. Glass fiber grating plates are arranged at both the top of the second filtering layer and the top of the first filtering layer to prevent loss of the polyether sponge and polyester sponge in case of flooding. A circular-hole cover plate of a steel concrete structure is arranged at the top of the filtering and oil-absorbing channel to facilitate opening and cleaning.

(11) A modified volcanic rock layer, a sawdust layer, a modified ceramsite layer, a configured planting soil layer and carbon sink vegetation are arranged successively from bottom to top in the ecologic purification channel. The modified volcanic rock layer is 40 cm high, filled with modified volcanic rocks with a particle size of 50 mm. The sawdust layer is 15 cm high, filled with sawdust with a particle size of 30 mm, and doped with microbial quick-dissolving balls at a volume ratio of 10%. The modified ceramsite layer is 50 cm high, filled with modified ceramsites with a particle size of 20 mm, and doped with microbial quick-dissolving balls at a volume ratio of 20%. The modified ceramsites are prepared by processing zeolite, fly ash, calcium carbonate and the like. The configured planting soil layer is 15 cm high, local planting soil and yellow sand are used, and the volume ratio of planting soil to yellow sand is 70:30. Prunus triloba, forsythia and Zoysia japonica are used as carbon sink vegetation. The configured planting soil layer is 10 cm below a road surface.

(12) The microbial quick-dissolving balls are internally filled with functional microorganisms which are mainly bacillus, Rhodobacter and Exiguobacterium sp. The microbial quick-dissolving balls are externally packed with a quick-dissolving material PVA and gradually dissolved in water to obtain an effect of uniform dispersion, so that microbial floras in the whole ecologic purification channel are distributed uniformly and stably. The microbial quick-dissolving balls not only have an extremely high removal efficiency for COD, but also enable deep nitrogen and phosphorous removal.

Example 2

(13) The sponge-type composite side ditch carbon neutralization system is implemented at a two-way four-lane highway, a design length of the catchment unit is 100 m, a length of the sponge-type composite side ditch of the unit is 45 m, wherein the silt pre-sedimentation channel of the unit is 8 m long, the filtering and oil-absorbing channel of the unit is 5 m long, and the ecologic purification channel of the unit is 32 m long.

(14) The silt pre-sedimentation channel of the unit is 1.5 m deep, 1 m wide, with a volume of 12 m.sup.3. The filtering and oil-absorbing channel of the unit is 1.5 m deep, 1 m wide, with a volume of 7.5 m.sup.3. The ecologic purification channel of the unit is 1.5 m deep, 2 m wide, at a length-width ratio of 16:1, with a volume of 96 m.sup.3.

(15) Considering a long distance for transportation of raw materials such as polyester sponge and polyether sponge around a highway, in order to reduce project costs and carbon emission in a construction stage, zeolite with a height of 50 cm and a particle size of 20 mm and block stones with a height of 50 cm and a particle size of 30 mm are laid in the filtering and oil-absorbing channel from bottom to top to replace the second filtering layer and first filtering layer, and a 5 cm oil-absorbing fiber layer is arranged.

(16) The modified volcanic rock layer of the ecologic purification channel is 50 cm high, filled with modified volcanic rocks with a particle size of 50 mm. The sawdust layer is 20 cm high, filled with sawdust with a particle size of 30 mm. The modified ceramsite layer is 60 cm high, filled with modified ceramsites with a particle size of 20 mm. The configured planting soil layer is 10 cm high, the volume ratio of planting soil to yellow sand is 70:30, and the configured planting soil layer is 10 cm below the road surface. Two rows of shrub are planted as the carbon sink vegetation, with a line spacing of 0.5 m: including one row of Ligustrum vicaryi, with a crown diameter of 30 cm and a row spacing of 1.0 m; and one row of purple-leaf plum, with a crown diameter of 20 cm and a row spacing of 1.0 m. The ecologic purification channel is fully covered with premature grass turf.

(17) The carbon emissions throughout a carbon life cycle of the sponge-type composite side ditch are measured and calculated as follows:

(18) (1) Carbon Emission in a Production Stage of Raw Materials

(19) The main raw materials for the highway sponge-type composite side ditch carbon neutralization system in this example are modified volcanic rocks, sawdust, zeolite, block stones, planting soil and yellow sand, all of which are natural materials and basically do not involve carbon emission. The modified ceramsites being fired will produce carbon emission, with a carbon emission coefficient of 135.52 kg CO/m.sup.3 according to the literature. A 45 m highway sponge-type composite side ditch carbon neutralization system is filled with modified ceramsites with a volume of 19.2 m.sup.3, and the carbon emission is 2.60 t.

(20) (2) Carbon Emission in a Construction Stage

(21) The carbon emission from construction of the highway sponge-type composite side ditch carbon neutralization system in this example mainly comes from the transportation and filling of various materials, the oil consumption level of highway diesel transportation is 3.2310.sup.5 tce/(t.Math.km) according to the literature, and the carbon emission in the construction stage of the 45 m highway sponge-type composite side ditch carbon neutralization system is measured and calculated as 0.51 t.

(22) (3) Carbon Sink in an Operation Stage

(23) According to the literature, Ligustrum vicaryi (with a carbon fixation coefficient of 27.69 g/d) and purple-leaf plum (with a carbon fixation coefficient of 32.87 g/d) with the best carbon sink effect locally are selected as the carbon sink vegetation, and premature grass (with a carbon fixation coefficient of 11.50 g/d) with the best carbon sink effect among herbaceous plants is selected. A daily fixed carbon content of the 45 m highway sponge-type composite side ditch carbon neutralization system is calculated as 0.33 kg, and a total fixed carbon content throughout a 20-year operation period is 3.11 t according to a planting condition of shrub and herbaceous plant.

(24) From the perspective of a whole life cycle of the highway sponge-type composite side ditch carbon neutralization system, the carbon emission is 3.11 t, the carbon sink is also 3.11 t, zero emission of carbon dioxide in the life cycle is realized, and this technology has become a true carbon neutralization technology in a life cycle of a highway.

(25) 1. Pollutant Removal Capacity of the Highway Sponge-Type Composite Side Ditch Carbon Neutralization System

(26) Experiment Example 1

(27) The highway sponge-type composite side ditch carbon neutralization system is as described in example 1. Samples were taken at the water inlet ditch, the silt pre-sedimentation channel, the water inlet of the filtering and oil-absorbing channel, the water outlet of the filtering and oil-absorbing channel and the water outlet of the ecologic purification channel respectively, the contents of pollutants TN, TP, COD and SS in the water samples in different positions were determined, wherein a total nitrogen (TN) was determined by potassium persulfate digestion-ultraviolet spectrophotometry, a total phosphorus (TP) was determined by phenol-hypochlorite spectrophotometry, a chemical oxygen demand (COD) was determined by a potassium dichromate method, and suspended solids (SS) were determined by a weighting method after dried. The test results are described in Table 2.

(28) TABLE-US-00003 TABLE 2 Purification Effect of Highway Sponge-type Composite Side Ditch Carbon Neutralization System (mg/L) Sampling Site TN TP COD SS Inlet ditch 5.4 0.2 53 305 Effluent from the silt pre- 2.8 0.15 32 130 sedimentation channel Effluent from the filtering 1.5 0.07 18 50 and oil-absorbing channel Effluent from the ecologic 0.9 0.05 8 25 purification channel

(29) Experimental result: Table 2 shows that the system provided by the present invention has a good purification effect on various pollutants in highway runoff.

(30) 2. Selection of Species of Microorganisms Filling the Microbial Quick-Dissolving Balls

(31) Nitrogen and phosphorus are main nutrient substances that induce water eutrophication. Studies indicate that some of the microorganisms have a higher nitrogen and phosphorus removal capacity. This experiment mainly investigated an influence of the species of microorganisms filling microbial quick-dissolving balls on a runoff purification effect. Different species of microorganisms were embedded in PVA and added into an organic glass reactor, a simulative water sample (with a total nitrogen concentration of 20 mg/L, a total phosphorus concentration of 2 mg/L) was added, and dissolved oxygen was controlled by aeration with DO=2-3 mg/L. A sample was taken in 10 h, and a total nitrogen concentration and a total phosphorus concentration were tested. This experiment was repeated three times for each microorganism species, and the results were averaged.

Experiment Example 2

(32) The highway sponge-type composite side ditch carbon neutralization system is as described in example 1, wherein the microorganism filling the microbial quick-dissolving balls was bacillus.

Experiment Example 3

(33) The highway sponge-type composite side ditch carbon neutralization system is as described in example 1, wherein the microorganism filling the microbial quick-dissolving balls was Rhodobacter.

Experiment Example 4

(34) The highway sponge-type composite side ditch carbon neutralization system is as described in example 1, wherein the microorganism filling the microbial quick-dissolving balls was Exiguobacterium sp.

Experiment Example 5

(35) The highway sponge-type composite side ditch carbon neutralization system is as described in example 1, wherein the microorganism filling the microbial quick-dissolving balls was Thauerasp.

Experiment Example 6

(36) The highway sponge-type composite side ditch carbon neutralization system is as described in example 1, wherein the microorganism filling the microbial quick-dissolving balls was Rhodopseudomonas rutila.

(37) TABLE-US-00004 TABLE 3 Influence of the Species of Microorganisms Filling the Microbial Quick- dissolving Balls on the Runoff Purification Effect Total Total Initial total ammonia Initial total phosphorus Phosphorus nitrogen concentration Nitrogen phosphorus concentration removal concentration in 10 h removal concentration in 10 h rate (mg/L) (mg/L) rate (%) (mg/L) (mg/L) (%) Example 20 7.8 61 2 0.59 70.5 2 Example 20 6.3 68.5 2 0.71 64.5 3 Example 20 8.2 59 2 0.67 66.5 4 Example 20 10.7 46.5 2 1.31 34.5 5 Example 20 11.4 43 2 1.24 38 6

(38) Experimental result: As shown in Table 3, the nitrogen and phosphorus removal effects of bacillus, Rhodobacter and Rhodopseudomonas rutila were relatively good. Thus, bacillus, Rhodobacter and Rhodopseudomonas rutila were preferred functional microorganisms embedded in the microbial quick-dissolving balls.

(39) 3. Comparison of Sewage Purification Effects of Different Kinds of Filter Materials for the Filtering and Oil-Absorbing Channel

Experiment Example 7

(40) The filtering and oil-absorbing channel is as shown in example 1, wherein the polyester sponge material was selected for the first filtering layer, the polyether sponge material was selected for the second filtering layer, and no oil-absorbing fiber layer was set.

(41) Experimental method: Samples were continuously introduced from the first water outlet by continuous water feeding, and the samples were simulative water samples with pollutant indexes as shown in Table 4. The samples were taken from the second water outlet after 10 h, and the contents of pollutants TN, TP, COD and SS in the samples were tested. A method for determining the contents of pollutants is as shown in example 1.

Experiment Example 8

(42) The filtering and oil-absorbing channel is as shown in example 1, wherein the polyester sponge material was selected for the first filtering layer, a foamed polypropylene material was selected for the second filtering layer, and no oil-absorbing fiber layer was set.

Experiment Example 9

(43) The filtering and oil-absorbing channel is as shown in example 1, wherein the foamed polypropylene material was selected for the first filtering layer, the polyether sponge material was selected for the second filtering layer, and no oil-absorbing fiber layer was set.

(44) TABLE-US-00005 TABLE 4 Comparison of Sewage Purification Effects of Different Kinds of Filter Materials for the Filtering and Oil-absorbing Channel TN TP SS (mg/L) (mg/L) COD (mg/L) Simulative 6.7 0.27 71 383 water sample Example 7 4.1 0.19 39 142 Example 8 4.6 0.22 46 153 Example 9 4.5 0.23 41 166

(45) Experimental result: As shown in Table 4, a purification effect of polyester sponge and that of polyether sponge are superior to that of the foamed polypropylene material, thus polyester sponge and polyether sponge are preferred filtering layer materials for the filtering and oil-absorbing channel.

(46) The contents described above are only the preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed above by the preferred embodiments, the preferred embodiments are not used to limit the present invention. Any technician familiar with this specialty can make some variations or modifications as equivalent embodiments with equivalent changes using the technical contents revealed above without departing from the scope of the technical solution of the present invention. However, for all those contents not departing from the scope of the technical solution of the present invention, any simple amendment, equivalent change and modification performed on the above examples according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.