A comprehensive treatment method for eutrophic water bodies

Abstract

The present invention discloses a comprehensive treatment method for eutrophic water bodies, comprising the following steps: S1, after salvaging phytoplankton in the eutrophic water body, injecting the water to be treated into a permeable hardened soil pit, collecting the remaining silt and distributing it to the permeable hardened soil pit to obtain a pond to be treated; S2, adding a degrading bacterial agent to the pond to be treated to obtain a target water body; S3, after the transparency of the target water body is restored, planting submerged plants in the target water body; S4, after the submerged plants grow stably, releasing fish and benthic aquatic animals into the target water body; S5, maintaining the number of submerged plants, fish and benthic aquatic animals in the target water body stable, and maintaining normal detection indicators in the target water body, thereby completing the treatment of the eutrophic water body. The method of the present invention can reduce the impact of excessive silt nutrients, limit the development of excessive eutrophication in the pond, and intercept suspended matter in the water, thereby shortening the treatment time.

Description

Technical Field

[0001] The present invention relates to the technical field of eutrophic water body treatment, and in particular to a comprehensive treatment method for eutrophic water bodies. Background Art

[0002] Due to the rapid development of social economy, the intensity of human activities in transforming nature has been increasing, and the eutrophication problem of natural water bodies and aquaculture water bodies has become increasingly serious.

[0003] Active research and attempts have been made to address eutrophic water bodies. From a technical perspective, these methods are primarily categorized into physical, chemical, and biological methods. Biological methods, with their low cost, low energy consumption, and ecological safety, have become a research hotspot in recent years. These methods primarily utilize aquatic organisms to absorb and utilize nitrogen and phosphorus for metabolic activities, thereby removing nutrients such as nitrogen and phosphorus from water bodies. This increases biodiversity, enhances the self-purification capacity of water bodies, and promotes a virtuous cycle in aquatic ecosystems, thereby achieving long-term control of eutrophic water bodies. However, biological methods are relatively slow in their effectiveness in addressing eutrophic water bodies.

[0004] Furthermore, biological treatment of eutrophic water bodies also presents the problem of difficult-to-control conditions and subsequent eutrophication. Currently, most biological treatments for eutrophic water bodies use an "in situ" approach, without treating the bottom soil of the water body. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention first injects water from the eutrophic water body into a permeable hardened soil pit, collects the remaining silt and distributes it to the permeable hardened soil pit to obtain a pond to be treated, and uses biological methods to treat the pond to be treated. The bottom of the permeable hardened soil pit can reduce the impact of excessive silt nutrients, limit the development of excessive eutrophication of the pond, and intercept suspended matter in the water, thereby shortening the treatment time and making it easy to achieve treatment conditions.

[0006] In order to achieve the above object, the present invention provides a comprehensive treatment method for eutrophic water bodies, comprising the following steps:

[0007] S1. After salvaging the phytoplankton in the eutrophic water, the water to be treated is injected into the permeable hardened soil pit, and the remaining silt is collected and distributed to the permeable hardened soil pit, thereby obtaining a pond to be treated and a soil pit without eutrophic water.

[0008] S2. Adding a degradation agent to the pond to be treated to obtain the target water body;

[0009] S3. After the transparency of the target water body is restored, submerged plants are planted in the target water body;

[0010] S4. After the submerged plants have grown stably, release fish and benthic aquatic animals into the target water body;

[0011] S5. Maintain the stable number of submerged plants, fish and benthic aquatic animals in the target water body, keep the detection indicators in the target water body normal, and complete the treatment of eutrophic water bodies.

[0012] Furthermore, the area of ​​the eutrophic water body in step S1 is 0.2 to 5 mu;

[0013] A plurality of water-permeable hardened soil pits are provided, and their total area and total water storage capacity are greater than or equal to the eutrophic water body. One or more water-permeable hardened soil pits may be provided, as long as the total area and total water storage capacity of the pits are greater than or equal to the eutrophic water body.

[0014] A pit containing eutrophic water is one that has been pumped out and the sludge removed. This sludge can be removed manually or mechanically. Since the pit is already relatively clean, treatment can be completed by adding a small amount of flocculants, pH adjusters, and fungicides.

[0015] Furthermore, the bottom of the soil pit treated with water permeability hardening in step S1 includes, from bottom to top,

[0016] Soil layer, compacted soil layer, rubble stone cushion layer with a thickness of 400-600mm, crushed stone powder layer with a thickness of 200-500mm, first medium sand layer with a thickness of 100-200mm, second medium sand layer with a thickness of 100-200mm, and 200-300mm pebble layer.

[0017] Furthermore, the compaction degree of the compacted soil layer is greater than 93%;

[0018] The ratio of crushed stone to stone powder in the crushed stone powder layer is 5-10:1-5;

[0019] A geotextile is further provided between the first medium sand layer and the second medium sand layer;

[0020] The diameter of the pebbles in the pebble layer is 50 to 200 mm.

[0021] Furthermore, the degradation bacterial agent in step S2 is EM bacteria, and its dosage is 3 to 7 kg / mu.

[0022] Furthermore, in step S3, after the transparency reaches 0.4 to 0.6 m, submerged plants occupying 10 to 30% of the target water area are planted;

[0023] The submerged plants include at least one of Potamogeton crispus, Hydrilla verticillata, Elodea nutans, and Vallisneria sinensis.

[0024] Furthermore, in step S4, the fish include crucian carp weighing 50-80 g / tail, silver carp weighing 150-200 g / tail, and carp weighing 150-200 g / tail, wherein the stocking amount is 150-300 crucian carp / mu, 150-250 silver carp / mu, and 150-25 carp / mu;

[0025] Benthic aquatic animals include snails, clams and cockles, and the release rate is 5 to 25 kg per mu.

[0026] Furthermore, in step S5, maintaining the number of submerged plants, fish and benthic aquatic animals in the target water body stable includes:

[0027] Regularly observe the growth of submerged plants, fish and benthic aquatic animals, as well as the biomass and community structure of phytoplankton in the target water bodies;

[0028] If submerged plants, fish and benthic aquatic animals die abnormally, the dead branches and leaves of submerged plants, dead fish and dead benthic aquatic animals should be removed promptly and replenished;

[0029] If the area of ​​submerged plants exceeds 40% of the target water body, fishing will be carried out to maintain the area of ​​submerged plants at 30-40%.

[0030] Furthermore, in step S5, the detection indicators in the target water body normally include:

[0031] Total nitrogen ≤1.5mg / L, ammonia nitrogen ≤0.05mg / L, total phosphorus ≤0.3mg / L, chlorophyll a ≤8mg / L.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The water in the eutrophic water body is injected into the permeable hardened soil pit, and the remaining silt is collected and distributed to the permeable hardened soil pit to obtain the pond to be treated. The biological method is used for treatment in the pond to be treated. The bottom of the permeable hardened soil pit can reduce the impact of excessive nutrients in the silt, limit the development of excessive eutrophication of the pond, and intercept suspended matter in the water, thereby shortening the treatment time and making it easy to achieve treatment conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1A flow chart showing a comprehensive treatment method for eutrophic water bodies according to an embodiment of the present invention is shown;

[0036] Figure 2 A schematic structural diagram of a soil pit bottom subjected to water-permeable hardening treatment according to an embodiment of the present invention is shown;

[0037] Description of reference numerals:

[0038] 1. Soil layer; 2. Compacted soil layer with a compaction degree of >93%; 3. 500mm thick rough stone cushion layer; 4. 300mm thick crushed stone powder layer; 5. 150mm thick first medium sand layer; 6. 200g / m 2 7. A second medium sand layer with a thickness of 150 mm; 8. A 300 mm pebble layer. DETAILED DESCRIPTION

[0039] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the specific embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] Example

[0042] In a eutrophic water body with an area of ​​about 2.8 mu and an average water depth of 2.02m (total phosphorus 0.331mg / L, total nitrogen 3.81mg / L, ammonia nitrogen 1.12mg / L, chlorophyll 122.3mg / L, transparency 0.3m), if Figure 1 As shown, the comprehensive treatment method for eutrophic water bodies of the present invention is used for treatment, including the following steps:

[0043] S1. After mechanically removing the floating aquatic plants from the eutrophic water, a pump was used to pump the water to be treated into a 2.9-acre, 2.5-meter-deep, permeable, hardened earth pit. The remaining silt was collected and distributed to the permeable, hardened earth pit, resulting in a pond to be treated and a pit free of eutrophic water. The permeable, hardened earth pit was located near the eutrophic water body and was mechanically excavated and then subjected to appropriate construction work.

[0044] like Figure 1 As shown in the figure, the bottom of the permeable hardened soil pit includes, from bottom to top, soil layer 1, compacted soil layer 2 with a compaction degree of >93%, 500mm thick rough stone cushion layer 3, 300mm thick crushed stone powder layer 4 (the ratio of crushed stone to stone powder is 7:3), 150mm thick first medium sand layer 5, 200g / m 2 geotextile 6, a second medium sand layer 7 with a thickness of 150 mm, and a 300 mm pebble layer 8.

[0045] At this point, the pit without eutrophication is obtained after the water in the pit has been pumped out and the sludge has been removed. The sludge can be removed manually or mechanically. The pit without eutrophication is already relatively clean and can be treated by adding a small amount of conventional flocculants, pH adjusters, fungicides, etc.

[0046] S2. Add 15 kg of EM bacteria to the pond to be treated, obtaining the target water body. In this embodiment, EM bacteria can be purchased commercially. EM bacteria are a mixture of beneficial bacteria, typically including photosynthetic bacteria, yeasts, lactic acid bacteria, and other beneficial bacteria. They are commonly used for food additives, livestock disease control, soil improvement, rooting and strengthening seedlings, and sewage treatment.

[0047] S3. After the transparency of the target water body is restored to 0.4m, submerged plants occupying 20% ​​of the target water body area are planted in the target water body. The submerged plants include Potamogeton crispus, Hydrilla verticillata, Elodea nutans, and Vallisneria sinensis in an area ratio of 5:4:1:2.

[0048] S4. After the submerged plants have grown stably, release fish and benthic aquatic animals into the target water body. For the release standards of fish and benthic aquatic animals, please refer to Tables 1 and 2.

[0049] Table 1 Fish stocking standards

[0050]

[0051] Table 2 Release standards for benthic aquatic animals

[0052]

[0053]

[0054] S5. Maintain the stable number of submerged plants, fish and benthic aquatic animals in the target water body, keep the detection indicators in the target water body normal, and complete the treatment of eutrophic water bodies.

[0055] Every 1 to 5 days, observe the growth of submerged plants, fish, and benthic aquatic animals, as well as the biomass and community structure of phytoplankton in the target water body;

[0056] If submerged plants, fish, and benthic aquatic animals die abnormally, the dead submerged plant branches and leaves, dead fish, and dead benthic aquatic animals are promptly removed and replaced. In this embodiment, the treatment period does not exceed one and a half years. The added fish are essentially unable to reproduce naturally, and their numbers remain relatively stable, with no increase or significant decrease. Benthic aquatic animals are growing well, with no significant mortality.

[0057] If the area of ​​submerged plants exceeds 40% of the target water body, they will be harvested. It is appropriate to maintain the area of ​​submerged plants at 30-40% of the target water body.

[0058] Table 3 shows the changes in water quality of the target water body before and after treatment.

[0059] Table 3 Changes in water quality of target water bodies before and after treatment

[0060]

[0061] The results in Table 3 show that water quality improved significantly after 300 days of treatment. After 400 days, the water quality met the target standards (total nitrogen ≤ 1.5 mg / L, ammonia nitrogen ≤ 0.2 mg / L, total phosphorus ≤ 0.06 mg / L, and chlorophyll a ≤ 8 mg / L). At this point, the target water transparency remained between 0.5 and 0.8 m, dissolved oxygen between 5 and 8 mg / L, and pH between 6.5 and 8.0. Most indicators met aquaculture water standards, completing the treatment of eutrophic water.

[0062] Comparative Example

[0063] Referring to the embodiment, a eutrophic water body (total phosphorus 0.356 mg / L, total nitrogen 3.65 mg / L, ammonia nitrogen 1.22 mg / L, chlorophyll 118.5 mg / L, transparency 0.3 m) with an area of ​​approximately 2.6 mu and an average water depth of 1.96 m is treated. The difference is that: in step S1, a machine is used to salvage the phytoplankton in the eutrophic water body, and then a water pump is used to inject the water to be treated into a pit with an area of ​​2.7 mu and a depth of 2.5 m. The pit is located near the eutrophic water body and is excavated by mechanical operation.

[0064] Table 4 shows the changes in water quality of the target water body before and after comparative treatment.

[0065] Table 4 Changes in water quality of target water bodies before and after comparative treatment

[0066]

[0067] It can be seen from the results in Tables 3 and 4 that the present invention can reduce the impact of excessive silt nutrients, limit the development of excessive nutrientization of ponds, and intercept suspended matter in water by treating the soil pit with permeable hardening, thereby shortening the treatment time and making the treatment conditions easier to achieve.

[0068] In summary, the present invention injects water from a eutrophic water body into a permeable hardened soil pit, collects the remaining silt and distributes it to the permeable hardened soil pit to obtain a pond to be treated, and then uses biological methods to treat the pond to be treated. Although digging the soil pit and treating the permeable hardened soil pit increases the initial cost, biological treatment can greatly reduce the time required for treatment. At the same time, soil pits without eutrophic water bodies can also be put into use after simple treatment. The treatment method of the present invention is very suitable for small eutrophic water bodies and has good application prospects.

[0069] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A comprehensive treatment method for eutrophic water bodies, characterized in that: The following steps are included: S1. After salvaging the phytoplankton in the eutrophic water, the water to be treated is injected into the permeable hardened soil pit, and the remaining silt is collected and distributed to the permeable hardened soil pit, thereby obtaining a pond to be treated and a soil pit without eutrophic water. S2. Adding a degradation agent to the pond to be treated to obtain the target water body; S3. After the transparency of the target water body is restored, submerged plants are planted in the target water body; S4. After the submerged plants have grown stably, release fish and benthic aquatic animals into the target water body; S5. Maintain the stable populations of submerged plants, fish, and benthic aquatic animals in the target waters, maintain normal test indicators in the target waters, and complete the treatment of eutrophic waters; The bottom of the soil pit treated with water permeability hardening in step S1 includes, from bottom to top, Soil layer, compacted soil layer, rubble stone cushion layer with a thickness of 400~600mm, crushed stone powder layer with a thickness of 200~500mm, first medium sand layer with a thickness of 100~200mm, second medium sand layer with a thickness of 100~200mm, and 200~300mm pebble layer.

2. The comprehensive treatment method for eutrophic water according to claim 1, characterized in that: The compaction degree of the compacted soil layer is greater than 93%; The ratio of crushed stone to stone powder in the crushed stone powder layer is 5-10:1-5; A geotextile is further provided between the first medium sand layer and the second medium sand layer; The diameter of the pebbles in the pebble layer is 50-200 mm.

3. The comprehensive treatment method for eutrophic water according to claim 1, characterized in that: The degradation bacterial agent described in step S2 is EM bacteria, and its addition amount is 3-7 kg / mu.

4. The comprehensive treatment method for eutrophic water according to claim 1, characterized in that: In step S3, after the transparency reaches 0.4-0.6 m, submerged plants occupying 10-30% of the target water area are planted; The submerged plants include at least one of Potamogeton crispus, Hydrilla verticillata, Elodea nutans, and Vallisneria sinensis.

5. The comprehensive treatment method for eutrophic water according to claim 1, characterized in that: In step S4, the fish include crucian carp weighing 50-80 g / tail, silver carp weighing 150-200 g / tail, and carp weighing 150-200 g / tail, wherein the stocking amount is 150-300 crucian carp / mu, 150-250 silver carp / mu, and 150-25 carp / mu; Benthic aquatic animals include snails, clams and cockles, and the release rate is 5~25kg / mu.

6. The comprehensive treatment method for eutrophic water according to claim 1, characterized in that: In step S5, maintaining the number of submerged plants, fish and benthic aquatic animals in the target water body stable includes: Regularly observe the growth of submerged plants, fish and benthic aquatic animals, as well as the biomass and community structure of phytoplankton in the target water bodies; If submerged plants, fish and benthic aquatic animals die abnormally, the dead branches and leaves of submerged plants, dead fish and dead benthic aquatic animals should be removed promptly and replenished; If the area of ​​submerged plants exceeds 50% of the target water body, fishing will be carried out to maintain the area of ​​submerged plants at 30~40%.

7. The comprehensive treatment method for eutrophic water according to claim 1, characterized in that: In step S5, the detection indicators in the target water body normally include: Total nitrogen ≤1.5mg / L, ammonia nitrogen ≤0.2mg / L, total phosphorus ≤0.06mg / L, chlorophyll a ≤8mg / L.

8. The comprehensive treatment method for eutrophic water according to any one of claims 1 to 7, characterized in that: The area of ​​the eutrophic water body in step S1 is 0.2 to 5 mu; A plurality of soil pits with permeable hardened bottom are set up, and the total area and total water storage capacity of the pits are greater than or equal to the eutrophic water body.

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