CN113979532B - A galvanic battery-type constructed wetland system with phosphorus recovery - Google Patents

Abstract

The invention discloses a galvanic battery-type constructed wetland system with phosphorus recovery function, which belongs to the field of sewage resource utilization. , the primary battery system uses the magnesium electrode as the negative electrode and the inert electrode as the positive electrode, and the magnesium electrode and the inert electrode are connected by wires; the inert electrode is inserted into the matrix layer, and the magnesium electrode is inserted into the phosphorus recovery device in the matrix layer, and the oxidation reaction is carried out through the oxidation reaction. Phosphorus is enriched on the magnesium electrode. The invention couples a magnesium negative electrode primary battery system in a constructed wetland system, the magnesium negative electrode is arranged in a phosphorus recovery device, and phosphorus is enriched near the magnesium negative electrode through the oxidation reaction of the magnesium negative electrode, thereby realizing the efficient recovery of phosphorus.

Description

A galvanic battery-type constructed wetland system with phosphorus recovery

technical field

The invention relates to the field of sewage resource utilization, in particular to a galvanic battery type constructed wetland system with phosphorus recovery function.

Background technique

Recovering phosphorus resources in the process of water treatment and realizing resource recycling can effectively alleviate the problem of shortage of phosphate rock resources.

Constructed wetlands use the comprehensive ecological effects of plants, substrates and microorganisms to achieve effective purification of sewage. It has the advantages of low investment in infrastructure, low operating costs, and beautiful ecological landscapes. It is used in water pollution control, recycled water reuse and ecological restoration in developing regions. The field has outstanding application advantages. Unlike carbon and nitrogen pollutants, which can be finally converted into gaseous substances and leave the wetland system under the action of microorganisms, constructed wetlands mainly intercept and accumulate phosphorus in the water body through mass adsorption and precipitation. However, once the adsorption capacity of the filler is approached or reached, the phosphorus removal efficiency of the constructed wetland will be greatly reduced, and even phosphorus release will occur. In addition, phosphorus is distributed and dispersed in wetlands, and efficient phosphorus recovery cannot be achieved.

In addition, in the process of sewage treatment, phosphorus can be converted into phosphate precipitates such as iron phosphate, aluminum phosphate, magnesium ammonium phosphate and hydroxyapatite, so as to realize the recovery of phosphorus. Wherein, based on the magnesium recovery phosphorus technology that utilizes the addition of chemical reagents such as sodium hydroxide and magnesium salts, the obtained product has a high phosphorus content; however, the chemical reagent addition method has high cost, complicated operation, and is inconvenient for large-scale application. .

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a galvanic battery-type constructed wetland system with phosphorus recovery function. The oxidation reaction of the magnesium anode causes phosphorus to be enriched near the magnesium anode, so as to realize the efficient recovery of phosphorus.

In order to achieve the above object, the present invention is realized by the following technical solutions:

The embodiment of the present invention provides a galvanic battery-type constructed wetland system with phosphorus recovery function, using a submerged flow constructed wetland system, including a matrix layer, and at least one galvanic battery system is arranged in the matrix layer, and the galvanic battery system uses magnesium electrodes. It is the negative electrode, the inert electrode is the positive electrode, and the magnesium electrode and the inert electrode are connected by wires;

The inert electrode is inserted into the matrix layer, the magnesium electrode is inserted into the phosphorus recovery device in the matrix layer, and phosphorus is enriched on the magnesium electrode through oxidation reaction.

As a further implementation manner, the phosphorus recovery device includes an inner sleeve and an outer sleeve sleeved together, the bottoms of the inner sleeve and the outer sleeve are closed; the inner sleeve is filled with a matrix layer.

As a further implementation, the magnesium electrode is inserted into the matrix layer in the inner sleeve, and neither the inert electrode nor the magnesium electrode is completely inserted into the matrix layer.

As a further implementation manner, the interval between the magnesium electrode and the inert electrode is less than or equal to the immersion length of the electrode in the matrix layer, and greater than or equal to 1/2 of the immersion length of the electrode;

The height of the inner sleeve is greater than the immersion height of the magnesium electrode.

As a further implementation manner, a plurality of through holes are opened on the side walls of the inner sleeve and the outer sleeve, and an accommodation space is formed between the outer sleeve and the inner sleeve.

As a further implementation manner, when there are multiple primary battery systems, the interval between any two primary battery systems is greater than the electrode immersion length.

As a further implementation manner, an ammeter is connected between the magnesium electrode and the inert electrode.

As a further implementation manner, the inert electrode is a graphite electrode.

As a further implementation, one side of the substrate layer is provided with a water inlet system, and the other side is provided with a water outlet system.

As a further implementation manner, the water inlet system adopts intermittent flow.

The beneficial effects of the present invention are as follows:

(1) The present invention couples a magnesium negative electrode primary battery system in a constructed wetland system, and the magnesium electrode undergoes an oxidation reaction to release magnesium ions, which combine with phosphate ions that move toward the magnesium electrode to generate phosphate precipitations such as magnesium ammonium phosphate, so that phosphorus in the The enrichment near the magnesium electrode can effectively remove and recover phosphorus resources, solve the problems of adsorption saturation and difficult phosphorus resource recovery in the existing constructed wetland technology, and realize the sustainability of phosphorus resources.

(2) One or more primary battery systems are arranged in the constructed wetland system of the present invention, which can generate electricity while realizing phosphorus recovery, realize energy reuse, reduce energy consumption for sewage treatment, and increase the extensiveness and environmental protection of constructed wetlands for sewage treatment. .

(3) The phosphorus recovery device of the present invention includes an inner sleeve and an outer sleeve that are sleeved together, the magnesium electrode is placed in the inner sleeve, the inner sleeve is filled with artificial wetland filler, the inner sleeve and the outer sleeve are There is no filler filling in between, reducing the resistance in the process of lifting the inner sleeve.

(4) The present invention is provided with a water inlet system and a drainage system, so that the water body in the output constructed wetland matrix forms a cycle, and the phosphorus in the sewage is enriched, precipitated and recovered by the phosphorus recovery device, and the water body output by the water inlet system adopts intermittent flow to ensure The constructed wetland is a hydrostatic system, and the water does not flow, so as to ensure the free diffusion of phosphate anions to the magnesium negative electrode.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

1 is a schematic structural diagram of the present invention according to one or more embodiments;

2 is a schematic structural diagram of a phosphorus recovery device according to one or more embodiments of the present invention;

Among them, 1. Wetland plants, 2. Water inlet, 3. Magnesium electrode, 4. Phosphorus recovery device, 5. Substrate layer, 6. Ammeter, 7. Graphite electrode, 8. Water outlet, 9. Inner sleeve, 10. Outer sleeve, 11, accommodating space, 12, cushion.

Detailed ways

Example 1:

This embodiment provides a galvanic battery-type constructed wetland system with phosphorus recovery. A submerged constructed wetland system is used, and a magnesium anode galvanic battery system is coupled to the constructed wetland system. The magnesium anode undergoes an oxidation reaction to release magnesium ions, which are combined with The action of phosphate ions moved by the magnesium negative electrode generates insoluble precipitates, which enriches phosphorus near the magnesium negative electrode, thereby realizing the efficient recovery of phosphorus.

Specifically, as shown in FIG. 1 , the constructed wetland system of this embodiment includes a matrix layer 5 , wetland plants 1 , a primary battery system, a phosphorus recovery device 4 , a water inlet system and a water outlet system, and the primary battery system is set in the matrix layer 5 . One or more, the interval between any two galvanic cell systems is greater than the electrode immersion length, so as to avoid mutual influence between the galvanic cell systems.

The material of the matrix layer 5 is non-conductive materials such as gravel, volcanic rock, and ceramsite.

The constructed wetland system of the present embodiment is further arranged with wetland plants 1, and the wetland plants 1 use any one or a combination of reeds, calamus, cattails and irises, and the planting density is uniform at a planting density of 9 to 25 plants/square meter. planting.

Further, the primary battery system includes a magnesium electrode 3, an inert electrode, the inert electrode is used as a positive electrode, and the magnesium electrode 3 is used as a negative electrode. In this embodiment, the inert electrode adopts a graphite electrode 7, and the graphite electrode 7 is vertically inserted into the matrix layer 5, And not completely immersed in the matrix layer 5; the magnesium electrode 3 is vertically inserted into the matrix layer 5 in the phosphorus recovery device 4, and the magnesium electrode 3 and the graphite electrode 7 have the same immersion depth.

In this embodiment, the immersion length of the magnesium electrode 3 and the graphite electrode 7 is 2/3 of the depth of the constructed wetland (the depth of the matrix layer 5), and the length outside the matrix layer 5 is 5 cm; the interval between the magnesium electrode 3 and the graphite electrode 7 is less than The immersion length of the electrode is equal to or greater than 1/2 of the immersion length of the electrode to ensure the electrolysis effect of the primary battery system.

It can be understood that, in other embodiments, the immersion lengths of the magnesium electrode 3 and the graphite electrode 7 can also be adjusted adaptively.

The magnesium electrode 4 in this embodiment is a pure magnesium or magnesium alloy electrode plate with a magnesium content of 95% or more.

Further, one end of the magnesium electrode 3 and the graphite electrode 7 located outside the matrix layer 5 is connected to an electrode clip respectively, a wire is connected between the two electrode clips, and an ammeter 6 is connected on the wire, and the generation of the primary battery system is detected by the ammeter 6. current.

In this embodiment, low-wattage LED lamps can be connected in series on the wires.

One side of the substrate layer 5 is provided with a water inlet system, and the other side is provided with a water outlet system. The water inlet system includes a water inlet 2 and a water inlet pipe connected with the water inlet 2. The installation height of the water inlet 2 in this embodiment is higher than the installation height of the water outlet 8, the sewage to be treated is injected into the matrix layer 5 through the water inlet system, and the water body after phosphorus recovery is discharged through the drainage system.

Among them, the inlet water adopts intermittent flow to ensure that the diffusion of ions in the system is not affected by the flow field.

Further, as shown in FIG. 2, the phosphorus recovery device 4 includes an inner sleeve 9, an outer sleeve 10 and a cushion layer 12, an outer sleeve 10, the diameter of the outer sleeve 10 is larger than the diameter of the inner sleeve 9, and the inner sleeve 9 sets It is arranged in the outer sleeve 10, and a accommodating space 11 is formed between the two.

The bottoms of the outer sleeve 10 and the inner sleeve 9 are flush, and they are blocked by the cushion layer 12 to form a structure with an open top and a closed bottom. The side walls of the outer sleeve 10 and the inner sleeve 9 are provided with a number of densely distributed through holes, and the size of the through holes is required not to allow the artificial wetland filler to pass through. The sewage penetrates into the phosphorus recovery device 4 through the through holes, and the sewage entering through the through holes of the outer sleeve 10 is stored in the accommodating space 11 .

The inner sleeve 9 is filled with the matrix layer 5, and the height of the inner sleeve 9 is greater than the immersion height of the magnesium electrode 3, that is, the bottom end of the magnesium electrode 3 has a certain distance from the cushion layer 12; the diameter of the inner sleeve 9 is larger than that of the magnesium electrode 3 diameter.

In this embodiment, the inner wall of the inner sleeve 9 is 5 cm away from the outer wall of the magnesium electrode 3, and the outer wall of the inner sleeve 9 is 5 cm away from the inner wall of the outer sleeve 10; the diameter of the cushion layer 12 is the same as that of the outer sleeve 10, and the height is 5 cm.

Of course, in other embodiments, the distance between the inner sleeve 9 and the outer sleeve 10, the distance between the inner sleeve 9 and the magnesium electrode 3, the height of the cushion layer 12, etc. can be adjusted to other values, which are determined according to the size requirements of the constructed wetland system. .

The outer sleeve 10 , the inner sleeve 9 and the cushion layer 12 are plastic products with strong insulation, load bearing and chemical resistance resistance, such as styrene-acrylonitrile copolymer, polypropylene and the like.

The using method of the constructed wetland system of the present embodiment is:

(1) The outer sleeve 10 is embedded in the wetland matrix layer 5 , and the embedded depth is 5 cm higher than the immersion length of the magnesium electrode 3 .

(2) Put the cushion layer 12 into the outer sleeve 10 to block the bottom end of the outer sleeve 10 .

(3) Put the inner sleeve 9 into the center of the cushion layer 12, and seal the bottom end of the inner sleeve 9.

(4) Put the magnesium electrode 3 into the center of the inner sleeve 9, fill the inner sleeve 9 with artificial wetland filler, and no filler is filled between the inner sleeve 9 and the outer sleeve 10, which reduces the process of lifting the inner sleeve 9. resistance.

The magnesium electrode 3 undergoes an oxidation reaction to release magnesium ions, which combine with the phosphate ions moving toward the magnesium electrode to form phosphate precipitation such as magnesium ammonium phosphate, so that phosphorus is enriched near the magnesium electrode 3 .

(5) When the ammeter 6 shows that the current is 15% of the initial value, the inner sleeve 9 and the substrate therein are taken out, and the substrate and the surface of the magnesium electrode 3 are rinsed with dilute acid to realize the recovery of phosphorus.

This embodiment is an organic combination of constructed wetland and magnesium primary battery technology. On the basis of strengthening phosphorus removal in constructed wetland, the distribution of phosphorus accumulation in constructed wetland is changed, phosphorus in water is efficiently recovered, and resource recovery is realized; at the same time, electricity is generated to realize energy Reuse, reduce the energy consumption of sewage treatment, and increase the extensiveness and environmental protection of sewage treatment by constructed wetlands.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims (9)

1. A galvanic cell type artificial wetland system with a phosphorus recovery function is characterized in that an undercurrent artificial wetland system is adopted, and the system comprises a substrate layer, wherein at least one galvanic cell system and a phosphorus recovery device are arranged in the substrate layer;

the primary battery system takes a magnesium electrode as a negative electrode and an inert electrode as a positive electrode, and the magnesium electrode is connected with the inert electrode through a lead;

the phosphorus recovery device comprises an inner sleeve and an outer sleeve which are sleeved together, and a cushion layer is arranged between the bottoms of the inner sleeve and the outer sleeve; the inner sleeve is filled with a matrix;

the inert electrode is inserted into the substrate layer, the magnesium electrode is inserted into the phosphorus recovery device in the substrate layer, and phosphorus is enriched in the phosphorus recovery device through oxidation reaction.

2. The galvanic artificial wetland system with phosphorus recovery of claim 1, wherein the magnesium electrode is inserted into the matrix layer in the inner sleeve, and neither the inert electrode nor the magnesium electrode is completely inserted into the matrix layer.

3. The galvanic artificial wetland system with phosphorus recovery function of claim 2, wherein the distance between the magnesium electrode and the inert electrode is less than or equal to the submergence length of the electrode in the substrate layer and more than or equal to 1/2 of the submergence length of the electrode;

the inner sleeve is higher than the magnesium electrode submerging height.

4. The galvanic artificial wetland system with phosphorus recovery function according to claim 1, wherein the side walls of the inner sleeve and the outer sleeve are provided with a plurality of through holes, and a containing space is formed between the outer sleeve and the inner sleeve.

5. The constructed wetland system of claim 1, wherein the distance between any two of the plurality of the galvanic cell systems is longer than the electrode immersion length.

6. The galvanic artificial wetland system with phosphorus recovery function of claim 1, wherein an ammeter is connected between the magnesium electrode and the inert electrode.

7. The galvanic artificial wetland system with phosphorus recovery function of claim 1, wherein the inert electrode is a graphite electrode.

8. The galvanic cell-type constructed wetland system with phosphorus recovery of claim 1, wherein the substrate layer is provided with a water inlet system on one side and a water outlet system on the other side.

9. The galvanic artificial wetland system with phosphorus recovery function of claim 8, wherein the water inlet system adopts intermittent flow.

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