The present invention will be further described below with reference to the accompanying drawings and embodiments. While the present invention will be described in conjunction with preferred embodiments, it should be understood that the invention is not intended to be limited to such embodiments. On the contrary, the invention is to cover alternatives, modifications and equivalents, which may be included within the scope of the invention as defined by the appended claims.
 see Figure 1 to Figure 2 As shown, the present invention is based on the phenomenon of the enrichment of organic matter in the cold trap 1 (or the cold water water pool at the bottom of the water body 7 or the deep pool for short) found by the applicant in practice, especially the low temperature water body in the deep pool can be relatively The long-term stable existence makes this low-temperature water body an important system for enriching most of the substances that cause eutrophication and the pollutants caused by eutrophication. The present invention uses this phenomenon to excavate or construct a certain scale of deep pools in eutrophic lakes and other water bodies, and uses natural or artificial help to form low-temperature water bodies in the iso-deep pools, and the low-temperature water bodies have enriched lakes and rivers. It can reduce or even eliminate harmful substances in lakes, rivers and other water bodies. We can design and excavate a certain number, spacing, area, depth and depth from the mouth of the deep pool to the water surface according to the volume of the water body, the concentration of pollutants, the temperature of the water body, and the local temperature of the deep pool and the shape of the water body surface and bottom. 6 deep pools such as distance. In one embodiment, as in a 500m 2 2-5 deep pools with a depth of 2-5M to 1M in diameter are dug out at the bottom of the lake in the small-scale water body. We can make use of the low ground temperature that often exists in the mud at the bottom 7 of water bodies (rivers, lakes, ponds, ponds, etc.), especially in summer and autumn when the surface water temperature of the water body is high and prone to algal bloom pollution, the ground temperature at the bottom 7 is often Still lower characteristics, and due to the lower temperature of the surface water due to the cold season sinking at the bottom of the water body 7, so that these low temperature water bodies maintain a lower temperature in the deep pool or cold trap 1, and even artificially reduce the deep pool. Or the cooling of the water in cold trap 1 keeps the water at a lower temperature.
 Cold traps 1 are generally arranged at the bottom 7 of shallow water bodies (including rivers, rivers, lakes, ponds, ponds, etc.) or artificially constructed under the water surface 6 or the environment or space maintained by low-temperature water bodies constructed using natural landforms, such as deep underwater pools. , water cold traps or underwater thermal insulation spaces, including cleaning and correcting the existing deep pools on the bottom of the water to make them have the ability to enrich the eutrophic substances in the water body. Utilize most of the substances that may cause eutrophication of water bodies, and the harmful substances in water bodies produced after eutrophication of water bodies have relatively low solubility in low temperature, so that harmful substances in water bodies are precipitated in artificially controlled low-temperature water bodies, thereby reducing all The concentration of harmful substances in the water body to be treated enables the water body to be treated. Sources of cold water in deep pools or cold traps 1 can include: 1. lower ground temperature of the underwater riverbed or lake bed; 2. cold water sinking in the deep pool or cold trap 1 during cold seasons to keep low temperatures; 3. nearby cold or geothermal currents Keeping low temperature in deep pool or cold trap 1; 4. Artificial control or human influence to keep the water temperature of deep pool or cold trap 1 at a lower temperature; .
 The cold trap 1 is in communication with the upper water body and can exchange substances. The size and quantity of the deep pools or cold traps 1 are related to factors such as the concentration of pollutants in the water body during the pollution period, the volume of the water body, the water temperature, and the removal rate of pollutants enriched in the deep pools or cold traps. The exit of the deep pool or cold trap 1 is below the water surface 6 . Appropriate processing can be carried out by using the available forms in the features of the bottom 7 of the water body to form a space that can preserve the lower temperature water body. Given that the substances enriched in deep pools or cold traps 1 are rich in organic matter or nutrients or high in carbon content, these substances can be used in agriculture, forestry, animal husbandry and fishery, energy industry or for carbon emissions trading.
 The actual work and observation found that a small number of cold traps 1 have improved the water quality of small-scale water bodies, and the number of cold traps 1 is adjusted according to the needs of water quality improvement, and manual interventions such as refrigeration make cold trap 1 more enriched. capacity of water pollutants. In the water body to be treated, excavate the space for storing cold water or low temperature water body, such as deep pools or cold traps1.
 like figure 1 : From left to right are near-shore cold trap 1, underwater cold trap 1, cold trap 1 processed or enclosed according to geomorphological features, directly constructing a container or a space or container that can be moved and can store a lower internal water temperature Cold trap 1 . The above cold trap 1 has a space for storing water with lower water temperature. The upper part of the cold trap 1 must have space for water exchange with the outside world. A mesh cover can be added to the upper opening of the cold trap 1 to prevent creatures or humans from accidentally entering the low-temperature water and being injured. According to the concentration of water pollutants such as DOC, DN, DP and other harmful substances in the water, as well as the low temperature and thermal conductivity of the bottom 7 of the water body, an accurately calculated low temperature water storage space can be constructed, and a cold water storage space can also be arbitrarily excavated or constructed. The pollutants in the space can be extracted or eliminated periodically or according to the total amount of pollutants enriched in the space of the constructed low-temperature water storage cold trap 1, so that the space has the ability to further enrich pollutants.
The principles of the present invention are as follows: 1. The solubility of most harmful substances, including organic substances, in low temperature water bodies is lower than the normal higher temperature environment, so that these substances are precipitated and enriched in a specific low temperature space with physicochemical properties. 2. Use water in ~4 o The characteristic of maximum density possessed by C makes 4 o The characteristics of water that can exist stably and maintain a lower temperature in an underwater bowl-like or barrel-like space, and 4 o Water above C has the characteristic that the density increases as the temperature decreases. 3. Taking advantage of the fact that the ground temperature under the deeper sediment at the bottom 7 of water bodies such as lake bottoms or river bottoms is lower than the water temperature of the water body during the eutrophic disaster, the cold trap 1 makes the bottom 7 naturally appear lower than the water body during the eutrophic disaster. temperature characteristics. At the same time, due to the changes in water temperature and ground temperature, if the temperature of the space under the water bottom (cold trap 1) cannot reach a sufficiently low temperature, the temperature in the cold trap 1 can be maintained at a lower temperature artificially.
 Examples of the application of the present invention are as follows: figure 2 , such as at 1000m 2 The average water depth of the lake is 2-3M (similar to the average water depth of Taihu Lake), and 2 cold traps 1 with a depth of 2M and a diameter of 1-1.5M are excavated at a suitable position near the shore of the lake or at the bottom of the lake. Generally speaking, the temperature of the lower part of the cold trap 1 will be lower than the temperature of the water body above the cold trap 1, and even lower than the average temperature of the water body. If the ground temperature in the lower part of the cold trap 1 is too high, which is not conducive to keeping the water in the cold trap 1 low, artificial refrigeration can be added to keep the temperature of the water in the cold trap 1 low, such as 4-10 o C. That is, the cooling capacity of the cold trap 1 is controlled according to the pollution status of the water body to be treated and the average water temperature in the occurrence season, as well as the surface water temperature and water temperature of the water body during the treatment period. It is also possible to control the water temperature in cold trap 1 to 4-10 o C, and keep a large temperature difference between the water temperature of the cold trap 1 and the water temperature of the water body. At the same time, in order to keep the water in cold trap 1 stable and save energy, according to the physical properties of water, try not to let the water temperature in cold trap 1 drop to 4 o C or less.
 In fact, in the implementation process, as long as the relationship between the ground temperature and the water temperature of the water body to be treated can be understood, it can be considered whether additional cooling is necessary according to the actual situation. If the bottom of the water body is 7 and the ground temperature is 10 o C below and basically stable, it can be simply excavated or enclosed at the bottom 7 of the water body, such as figure 1 The cold trap shown is sufficient. As for the volume and number of cold traps, it can be designed according to the pollution degree of the water body, or a small number of cold traps can be set up but the harmful substances enriched in the cold traps are often removed so that the space of the cold traps can continue to maintain the ability to effectively enrich harmful substances. If the set number is not enough to effectively reduce pollution and harmful substances, this can appropriately increase the number of cold traps.
 application figure 2 The cold trap 1 shown is a small-scale experiment, and the results of the enriched substances in the experimental container are shown in the table:
 Test number Surface water temperature ( o c) Container water temperature ( o c) Weight of enriched solids (0.5 hours) Weight of enriched solids (1 hour) Weight of enriched solids (2 hours) 7.5 28 5 1g 5g 10g 8.1 30 4 2g 8g 15g
 The above test confirmed to a certain extent the feasibility and effectiveness of the cold trap 1 for water pollution control: the above device was placed 15cm below the water surface 6 (the water depth was about 2M), and after a certain period of time, obvious black spots appeared in the container. Brown precipitation material, but no obvious precipitation material in the comparison experiment without refrigeration device of the same size. The weight of the material in the above table is the dry weight of the precipitate after drying.