CN103570137A - Design method of underflow manual wetland matrix structure based on flow field distribution - Google Patents

Abstract

The invention discloses a design method of an underflow manual wetland matrix structure based on flow field distribution. The method performs quantification design on main structural parameters influencing underflow manual wetland flow field distribution based on a seepage field theory, taking uniform distribution of a water flow around a bed body as a purpose, and taking a three-dimensional finite difference underground water flowing mathematical model as a design calculation basis, wherein the main structural parameters include manual wetland unit division, unit pond body length-width ratios, water distribution area length, water collection area length, bed body depth, filling layers of a main body filler area, and filler permeability coefficients; matrix fillers are measured by a Darcy permeability test; the fillers with required particle size are screened out. When the design method performs design calculation on the structural parameters of underflow manual wetland, the selection of the structural parameters is simple, convenient and practicable; the underflow manual wetland constructed according to the design method can greatly improve and increase the hydraulic efficiency of a system and utilization ratios of the fillers, can avoid a channel flow, a short flow and a dead area, and can further improve and prolong a purifying effect and the service life.

Description

A kind of drowned flow artificial wet land matrix structure method of design based on Flow Field Distribution

Technical field

The invention belongs to a kind of innovative design to drowned flow artificial wet land matrix structure, particularly a kind of drowned flow artificial wet land matrix structure method of design based on Flow Field Distribution.

Background technology

In water pollution and shortage of water resources problem increasingly serious today, as the Artificial Wetland Techniques of ecological treatment method, there is wide development space.Artificial swamp can be divided into underflow type artificial wet land, vertical current constructed wetland and surface current artificial wetland according to water body fluidised form, wherein underflow type artificial wet land range of application is the most extensive, compare with traditional biochemical processing method, have processing cost low, manage simple and easy, treatment effect good, be difficult for causing the advantages such as environmental health problem.

In recent years, progressively expansion along with artificial swamp through engineering approaches range of application, the problems such as channel, short stream, dead band become increasingly conspicuous, matrix utilization ratio declines year by year, and cause thus that processing efficiency is low, the series of problems such as obstruction and length of service shortening, become the bottleneck problem that artificial swamp is further promoted the use of.In the case, research finds that the structure of Traditional Man wetland still rests on the empirical construction phase, lacks effective method of design, has caused the generally generation of the Flow Field Distribution non-uniform phenomenons such as channel, short stream, dead band.For the problems referred to above, the present invention is theoretical according to seepage field, with even flow field, be distributed as object, utilize the basic current mathematical model of Chang Midu triflux to carry out quantification to underflow type artificial wet land structural parameter, in the design phase, avoided matrix utilization ratio low, the generation of the problems such as current skewness, for the raising of underflow type artificial wet land detergent power and the length of service provides technical support.

Summary of the invention

The object of this invention is to provide a kind of drowned flow artificial wet land matrix structure method of design based on Flow Field Distribution, according to seepage theory, underflow type artificial wet land bed structure parameter is carried out to quantification, solved randomness and the empirical problem of underflow type artificial wet land in design and manufacture process, with the homogeneity that guarantees that matrix interior flow field distributes.

Drowned flow artificial wet land matrix structure method of design is to take being uniformly distributed as object of flow field, and design calculation is according to being Three dimensional finite difference groundwater flow movable model, and the basic current numerical model of its Chang Midu triflux is as follows:

$\frac{\∂}{\∂x}\left(k_{\mathrm{xx}}\frac{\∂h}{\∂x}\right)+\frac{\∂}{\∂y}\left(k_{\mathrm{yy}}\frac{\∂h}{\∂y}\right)+\frac{\∂}{\∂z}\left(k_{\mathrm{zz}}\frac{\∂h}{\∂z}\right)-w=S\frac{\∂h}{\∂t}$

In formula: k _xx, k _yy, k _zzfor along x, y, the permeability coefficient (LT on z change in coordinate axis direction ^-1); H is piezometric head, (L); W is the Yuan Hehui of underground water; S is the water storage rate (L of pore media ^-1); The t time (T).

Concrete steps are:

(1) set up a drowned flow artificial wet land:

Drowned flow artificial wet land matrix structure method of design for drowned flow artificial wet land structure comprise main body packing area, catchment area, the water outlet that water-in, cloth pool, layering are filled; Sewage is flowed into by water-in, and behind cloth pool, horizontal flow is crossed each packing layer in main body packing area, imports catchment area, finally by water outlet outflow system at main body reaction zone end.

The single pond of drowned flow artificial wet land body unit length range is 1-56 rice, and Aspect Ratio is 1:1-2:1; The suitable proportion scope of water distribution section length and artificial swamp pond body total length is 1:8-1:15; The suitable proportion scope of catchment area length and artificial swamp pond body total length is 1:8-1:15; The effective depth of cracking closure of bed body filler is 0.5-1.0 rice; When single pond body total length is less than 12 meters, main body filler is divided into 4-6 layer, and when single pond body total length is greater than 12 meters, main body filler is divided into 3-6 layer; Cloth pool and catchment area be suitable, and to select the permeability coefficient of filler be 500-1000m/d; If unit cells body length is greater than 56 meters, according to landform, by land divide, be several pond body units, guarantee that each unit cells body length is within the scope of 1-56 rice.

(2) design of each layer of filler permeability coefficient:

The selection of each layer of filler in drowned flow artificial wet land main body packing area is relevant to artificial swamp unit cells body yardstick, and the specific design of each layer of filler permeability coefficient of different scale artificial swamp is as follows:

1. when Chi Tichang is during at 1m-6m, each layer of permeability coefficient calculation formula is as shown in (1):

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (2):

$a={0.0002k}_1^{3.0537}---\left(2\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-80m/d.

2. when Chi Tichang is during at 6m-12m, each layer of permeability coefficient calculation formula is as shown in (3):

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (4):

$a={0.0009k}_1^{2.0052}---\left(4\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-120m/d.

3. when Chi Tichang is during at 12m-56m, each layer of permeability coefficient calculation formula is as shown in (5):

k _n＝a[n ²-(0.0998a+5.6559)n+58.653a ^-0.4483] （5）

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (6):

$a={0.0003k}_1^{2.0578}---\left(6\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-140m/d.

(3) choosing of each layer of filler in drowned flow artificial wet land main body packing area:

Adopt darcy permeability test to measure matrix fill, filter out the filler of each layer of required particle diameter.

The present invention is a kind of innovative design to drowned flow artificial wet land matrix structure, to utilize seepage action of ground water theory to carry out Quantitative design to the bed structure parameter of the drowned flow artificial wet land of different scale, realize the object that even flow field distributes, to promote the utilization ratio of artificial swamp hydraulic efficiency and bed body filler, give full play to filler to the holding back of pollutent, absorption and co-precipitation, promote the decontamination effect improving of artificial swamp to pollutent, solved randomness and the empirical problem of Traditional Man wetland at bed structure design aspect.While adopting this method of design to carry out design calculation to each structural parameter of drowned flow artificial wet land, choosing of structural parameter is simple and convenient, practical, the drowned flow artificial wet land of building accordingly can improve the hydraulic efficiency of system and the utilization ratio of filler greatly, avoid the generation in channel, short stream and dead band, and then improve decontamination effect improving and working life.

Accompanying drawing explanation

Fig. 1 is the drowned flow artificial wet land cross-sectional view of embodiment of the present invention layering matrix.

Mark in figure: 1-water-in, 2-cloth pool, 3-layering matrix body packing area, 4-catchment area, 5-water outlet, 6-waterplant.

Fig. 2 is the drowned flow artificial wet land cross-sectional view of embodiment of the present invention homogeneous matrix.

Mark in figure: 1-water-in, 2-cloth pool, 4-catchment area, 5-water outlet, 6-waterplant, 7-homogeneous matrix body packing area.

Fig. 3 is two drowned flow artificial wet land cloth pools of the embodiment of the present invention, catchment area and each layer of water amount comparison diagram, and A figure is layering matrix, and B figure is homogeneous matrix.

In figure: Zone1, Zone2 represent respectively the total water amount in cloth pool and catchment area; Zone3-Zone8 is the water amount of each layer from top to bottom successively.

Fig. 4 is two drowned flow artificial wet land water outlet spike conditional curve figure of the embodiment of the present invention.

Embodiment

Embodiment:

(1) for embodying validity of the present invention, setting up two underflow type artificial wet lands of layered structure and homogeneous matrix contrasts, two underflow type artificial wet lands are except having any different in main body packing area, other structures form all consistent, as shown in Figure 1, 2, drowned flow artificial wet land structure comprises water-in 1, cloth pool 2, layering matrix body packing area 3, catchment area 4, water outlet 5, waterplant 6 and homogeneous matrix body packing area 7; Sewage is flowed into by water-in 1, and behind cloth pool 2, horizontal flow is crossed layering matrix body packing area 3 or homogeneous matrix body packing area 7; There is waterplant 6 on matrix top layer; Sewage imports catchment area 4 by main body reaction zone end; Finally by water outlet 5 outflow systems; Water-in 1 bore is 32 millimeters, and water outlet 5 bores are 32 millimeters.Waterplant 6 is humidogene emergent Canna generalis Bailey, planting density be 20 strains/square metre.

Two drowned flow artificial wet land pond bodies are stainless steel materials, according to the moving basic results of numerical model calculation of Chang Midu THREE DIMENSIONAL GROUNDWATER FLOW, pond body length is designed to 2 meters, width is 1.2 meters, long-width ratio is 1:0.6, and cloth pool 2 is all 0.2 meter with the length of catchment area 4, with pond body total length ratio be 1:10, cloth pool 2 is 500m/d with the permeability coefficient of catchment area 4 filling substrates, and filler is chosen the pebbles that particle diameter is 4cm-8cm.The effective depth of cracking closure of bed body is 0.6m, because pond body total length is less than 12 meters, therefore layered structure artificial swamp main body filler is divided into 6 layers, each layer height is consistent, filling substrate is quartz sand, difference is that quartz sand particle size is different, and the size of each layer of quartz sand particle size is to calculate after permeability coefficient, utilizes darcy experiment to determine.

(2) selection of each layer of filler in drowned flow artificial wet land main body packing area is relevant to artificial swamp unit cells body yardstick, and the specific design of each layer of filler permeability coefficient of different scale artificial swamp is as follows:

1. when Chi Tichang is during at 1m-6m, each layer of permeability coefficient calculation formula is as shown in (1):

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (2):

$a={0.0002k}_1^{3.0537}---\left(2\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-80m/d.

2. when Chi Tichang is during at 6m-12m, each layer of permeability coefficient calculation formula is as shown in (3):

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (4):

$a={0.0009k}_1^{2.0052}---\left(4\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-120m/d.

3. when Chi Tichang is during at 12m-56m, each layer of permeability coefficient calculation formula is as shown in (5):

k _n＝a[n ²-(0.0998a+5.6559)n+58.653a ^-0.4483] （5）

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (6):

$a={0.0003k}_1^{2.0578}---\left(6\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-140m/d.

This model is filled Calculation Method in Penetrating Coefficient coincidence formula (1), according to existing quartz sand, designs, and it is 25m/d that layering matrix is set top layer matrix permeability coefficient, meet the requirement that the first layer span is 10-80m/d, bring formula (2) into and obtain a value, by a substitution formula (1) drawing, and n is got to 2 successively, 3,4,5,6, calculate matrix the 2nd, 3 ... the permeability coefficient of 6 layers, layering and homogeneous model need the permeability coefficient of matrix as shown in table 1.

Table 1 is surveyed gathering of each layer of corresponding filler permeability coefficient of matrix by darcy permeability test

(3) utilize quartz sand particle size corresponding to each layer of permeability coefficient of darcy measuring, experiment relative error is controlled in 5%, draw layered structure artificial swamp main body packing area 3 from top to bottom each layer of quartz sand particle size respectively be 0.2-0.6mm, 0.2-0.4mm, 0.2-0.8mm, 0.4-0.6mm, 0.4-0.9mm and 1.0-2.0mm, homogeneous matrix body packing area 7 is homogeneous matrix fill (for the quartz sand of 0.9-2.0mm).

First, utilize method for numerical simulation to compare the water amount of two kinds of different filling modes, result as shown in Figure 3, A figure is that artificial swamp inhalant region (zone1), catchment area (zone2) and the main body packing area water flux density of six layers of packing area (zone3-zone8) is from top to bottom filled in layering, six filler regions (zone3-zone8) the mistake circulation homogeneous phase that can find out main body packing area different depths is same, and Flow Field Distribution is even; And B figure is homogeneous matrix fill artificial swamp in Fig. 3, there is larger difference in different depths main body packing area (zone3-zone8) water flux density, and Flow Field Distribution is inhomogeneous.

The sodium-chlor of take is carried out tracer experiment as tracer agent two system hydraulic performances is contrasted, and flow set is 48L/h, and tracer experiment result as shown in Figure 4, is calculated two comparison system water-power performance parameters according to Fig. 4 experimental result, as shown in table 2.

Table 2 is obtained the correlation parameter of two kinds of different filling modes by tracer experiment

Filling mode	Effective volume compares e	Short circuit value S	Hydraulic efficiency λ	The rate of recovery (%)
					Layering matrix	0.86	0.51	64	85.08
Homogeneous matrix	0.62	0.62	42	74.15

From Fig. 4 and table 2, the effective volume ratio of layering matrix drowned flow artificial wet land, hydraulic efficiency are all high than the artificial swamp of traditional homogeneous matrix filling mode, show that the drowned flow artificial wet land of layering filling mode has better hydraulic performance.Visible, in according to the present invention to the method for design of artificial swamp matrix structure to the filling of drowned flow artificial wet land matrix carry out reasonably combined after, can obviously reduce the existence in dead band and backwater district in wet land system, different depths regional flow in a body is uniformly distributed, effectively improve matrix utilization ratio and conservancy property, thereby be more conducive to the removal of pollutent.

The above, be only to this design exemplifying embodiment, not the design's method done to any pro forma restriction, and any simple change and modification that every technical spirit according to the design is done above example still belong to the protection domain of this Analyzing on Building A Planning Scheme.

Claims (1)

1. the drowned flow artificial wet land matrix structure method of design based on Flow Field Distribution, is characterized in that concrete steps are:

(1) set up a drowned flow artificial wet land:

Drowned flow artificial wet land matrix structure method of design for drowned flow artificial wet land structure comprise main body packing area, catchment area, the water outlet that water-in, cloth pool, layering are filled; Sewage is flowed into by water-in, and behind cloth pool, horizontal flow is crossed each packing layer in main body packing area, imports catchment area, finally by water outlet outflow system at main body reaction zone end;

The single pond of drowned flow artificial wet land body unit length range is 1-56 rice, and Aspect Ratio is 1:1-2:1; The suitable proportion scope of water distribution section length and artificial swamp pond body total length is 1:8-1:15; The suitable proportion scope of catchment area length and artificial swamp pond body total length is 1:8-1:15; The effective depth of cracking closure of bed body filler is 0.5-1.0 rice; When single pond body total length is less than 12 meters, main body filler is divided into 4-6 layer, and when single pond body total length is greater than 12 meters, main body filler is divided into 3-6 layer; Cloth pool and catchment area be suitable, and to select the permeability coefficient of filler be 500-1000m/d; If unit cells body length is greater than 56 meters, according to landform, by land divide, be several pond body units, guarantee that each unit cells body length is within the scope of 1-56 rice;

(2) design of each layer of filler permeability coefficient:

The selection of each layer of filler in drowned flow artificial wet land main body packing area is relevant to artificial swamp unit cells body yardstick, and the specific design of each layer of filler permeability coefficient of different scale artificial swamp is as follows:

1. when Chi Tichang is during at 1m-6m, each layer of permeability coefficient calculation formula is as shown in (1):

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (2):

$a={0.0002k}_1^{3.0537}---\left(2\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-80m/d;

2. when Chi Tichang is during at 6m-12m, each layer of permeability coefficient calculation formula is as shown in (3):

k _n＝a[n ²-(0.0762a+5.3485)n+36.927a ^-0.3828] （3）

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (4):

$a={0.0009k}_1^{2.0052}---\left(4\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-120m/d;

3. when Chi Tichang is during at 12m-56m, each layer of permeability coefficient calculation formula is as shown in (5):

k _n＝a[n ²-(0.0998a+5.6559)n+58.653a ^-0.4483] （5）

In formula: k _nthe permeability coefficient of-n layer filler, n is 2,3,4,5,6;

N-number of plies value (2,3,4,5,6) from top to bottom;

A-coefficient, its calculation formula is as shown in (6):

$a={0.0003k}_1^{2.0578}---\left(6\right)$

In formula: k ₁the permeability coefficient value of-the first layer (top layer), span is 10-140m/d;

(3) choosing of each layer of filler in drowned flow artificial wet land main body packing area:

Adopt darcy permeability test to measure matrix fill, filter out the filler of each layer of required particle diameter.

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