CN113800643B

CN113800643B - Algae resource utilization method for algae bloom prevention and control and device applied to method

Info

Publication number: CN113800643B
Application number: CN202111194744.8A
Authority: CN
Inventors: 王宇庭; 黎沼鹏; 张易祥; 肖明莉; 李晓明; 欧阳苗锋
Original assignee: Huzhou University
Current assignee: Huzhou University
Priority date: 2021-10-13
Filing date: 2021-10-13
Publication date: 2023-04-07
Anticipated expiration: 2041-10-13
Also published as: CN113800643A

Abstract

The invention relates to an alga resource utilization method for algal bloom prevention and control and a device applied to the method, the alga resource utilization method for algal bloom prevention and control comprises the following steps of S10, arranging a plurality of containment net cages (10) provided with hydraulic jetting mechanisms (20) in a water body, and putting carnivorous fishes, herbivorous fishes and omnivorous fishes in the containment net cages (10); step S20, spraying water towards the water body by the hydraulic spraying mechanism (20) to rotate the water body inside and outside the enclosure net cage (10) so as to lead the algae to be gathered towards the interior of the enclosure net cage (10) through the netting of the enclosure net cage (10); and step S30, periodically removing the slowly growing fishes in the enclosure net cage (10) to prevent the existing quantity of the fishes from being too large and supplementing juvenile fishes. The method and the device for algae resource utilization for algae bloom prevention and control have the advantages that a physical method and an ecological method are fused, the advantages are brought forward, the disadvantages are avoided, and the method and the device for algae resource utilization for algae bloom prevention and control are stable in system operation and good in effect.

Description

Algae resource utilization method for algae bloom prevention and control and device applied to method

Technical Field

The invention belongs to the field of water environment protection, and particularly relates to an algae resource utilization method for algae bloom prevention and control and a device applied to the method, which are suitable for ecological restoration of eutrophic water bodies of floating algae blooms in micro-flow or static lakes, ponds, wetlands and riverways.

Background

Water eutrophication is an environmental problem facing the world, in particular to China with deficient water resources and rapid economic development. The phenomenon of water bloom caused by the massive growth of algae is one of the main manifestations of water eutrophication. The "water bloom" occurs for the following reasons: firstly, the accumulation of plant nutrient salt in water caused by non-point source pollution reaches a certain concentration threshold; secondly, the number of the small animals eating the algae is unstable, and the massive propagation of the algae cannot be inhibited in time; thirdly, after the algal bloom population becomes a dominant population and reaches a certain dominance degree, the competitive action of other algae is inhibited, and the algal bloom population is continuously expanded, wherein the algal bloom formed by the blue algae which has strong viability and can exist in a large number in a population form is the most common.

In order to repair eutrophication of water bodies and inhibit algal blooms, a great deal of exploration and practice is carried out. In summary, two main processing modes are identified.

One mode is to adopt a physical method to collect algae and then directly separate the algae from a water body or further inactivate the algae, for example, the algae removing device for the hydraulic engineering disclosed in the Chinese patent document CN 211470804U is characterized in that a waterproof motor is matched with a device shell and fan blades, when the fan blades are started, vortex can be formed in water, so that algae floating on the water surface is attracted to the top of the device shell, and then a scraping device and a collecting plate are used for collecting the algae and taking the algae away from the water surface. Also, for example, chinese patent document CN 110130285A discloses an algae removal system, which forms a vortex by the rotation of a first impeller on an algae collecting device to collect algae-laden water mixed liquid to a diversion port, and then physically inactivates the algae-laden water mixed liquid and generates a precipitate to achieve the purpose of removal. Although the mode is effective, the energy consumption is high, the adverse effect on aquatic organisms is also high, and the recycling degree of algae is low.

In another mode, an ecological method is adopted, for example, chinese patent document CN 103214096A discloses an algae bloom control method based on a biological chain relationship, which selects suitable wetland organisms according to wetland hydrological processes and seasonal variation characteristics by means of a net-isolation floating island, a multi-layer net-support floating island, a wetland plant artificial planting technology and an aquatic animal stocking technology, and constructs an algae bloom control method based on the biological chain relationship to form a complete wetland biological chain structure, thereby achieving the goal of controlling algae bloom outbreak in the wetland water body. The mode has low energy consumption, small adverse effect on water organisms and relatively high resource utilization degree, but an ecological system is not easy to stably operate, and the phenomenon of system failure often occurs.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, combines a physical method and an ecological method, develops advantages and avoids disadvantages, and obtains a set of algae resource utilization method which is stable in system operation and good in effect and is used for controlling algal bloom.

The scheme for solving the technical problems comprises the following steps:

the algae resource utilizing method for algae bloom prevention and control includes the following steps,

s10, arranging a plurality of enclosure net cages provided with hydraulic jet mechanisms in a water body, and putting carnivorous fishes, herbivorous fishes and omnivorous fishes in the enclosure net cages;

step S20, spraying water to the water body by the hydraulic spraying mechanism to rotate the water body inside and outside the enclosure net cage so that the algae are gathered towards the interior of the enclosure net cage through the netting of the enclosure net cage;

and step S30, periodically removing the slowly growing fishes in the enclosure net cage to prevent the existing quantity of the fishes from being too large, and supplementing juvenile fishes.

The invention conception of the invention is as follows:

(1) Different from destructive algae collection modes in the prior art, the water power jet mechanism is adopted to enable the water body to generate vortexes, the water body cannot be rotated in a powerful mode, and adverse physical influences on aquatic organisms are not easily caused;

(2) The vortex generated in the water body can enable algae cells to be mixed with organic debris and soil particles in the water body to generate organic floccules, the organic floccules are eaten by aquatic organisms such as fishes and the like in the enclosure net cage, so that the algae are recycled, and the effect of clarifying water quality is achieved, wherein the aged algae are easy to generate the organic floccules with the organic debris and the soil particles in the water body due to small activity;

(3) The aged algae is easier to be adsorbed by the netting because of small activity and then is ingested by the omnivorous fishes with scraping or sucking properties, so that the resource utilization is realized;

(4) Because water flows in the enclosure net cage, and organic floccules formed by aggregation of algae are natural baits of small fishes and shrimps, small native fishes and shrimps can gather towards the interior of the enclosure net cage, and large native fishes can gather outside the net, so that a biological gathering area of a closed-loop food net is formed inside and outside the enclosure net cage, and the density of organisms in the area can be increased along with the input of exogenous nutrient substances in a water body and the improvement of illumination conditions, and the organisms can be diffused to the periphery, so that the area with improved surrounding water quality is continuously expanded, and an automatic adjusting system for inhibiting the growth of the algae is formed;

(6) In order to prevent excessive native omnivorous fishes in the enclosure net cage and inhibit the density of zooplankton, carnivorous fishes are put in the enclosure net cage; in order to prevent the invasion of aquatic weeds, herbivorous fishes or omnivorous fishes which can eat aquatic weeds are put in; in order to prevent the meshes of the net cage from being blocked by the attached organisms, omnivorous fishes which can be scraped or sucked are thrown to eat the attached algae and animals on the netting, and the permeability of the netting to water is maintained.

The algae resource utilization method can remove aged algae cells and purify water, so that viable fresh algae cells grow healthily, thereby optimizing the community structure of floating algae and improving the primary productivity of water; meanwhile, carnivorous fishes in the tank inhibit omnivorous fishes to protect the stable density of zooplankton, the efficiency of food chain energy transfer is further promoted, the growth of aquatic animals such as fishes is promoted, the eutrophication ecological restoration of the water body is realized, and meanwhile, the nutrient substances in the water body are recycled.

As an improvement, the hydraulic jet mechanism takes the center of the enclosure net cage as a circle center and sprays water along the circular tangential direction, so that water inside and outside the enclosure net cage rotates.

As an improvement, the hydraulic jet mechanism is a jet pipeline arranged on the inner side or the outer side of the enclosure net box, and the jet pipeline sprays water to a water body through an opening on the jet pipeline.

As an improvement, the organisms put in the enclosure net cage comprise one or more of fish, shrimps, crabs, shellfish and native fish, wherein the native fish refers to wild fish naturally growing in a water body.

As a further improvement, the shrimps put into the enclosure net cage are freshwater shrimps, namely Japanese macrobrachium nipponensis. The prior art considers that: algae inhibit the growth of freshwater shrimps, so that water with algae is not generally used for culturing freshwater shrimps. However, the inventor finds that more freshwater shrimps with different sizes can be collected in the enclosure net cage through experiments, and the ecological system is favorable for the growth and development of the freshwater shrimps. This finding is different from the prior art and the cause of this phenomenon is not clear: probably because the algae entering the enclosure net cage, the organic debris and the soil particles rotate together to form an organic floccule, part of algae toxins (adsorbed by soil colloid or consumed by microorganisms) are detoxified, and the freshwater shrimps cannot be poisoned; another reason may be that the present solution is primarily directed to preventing bloom development, and the algae have not produced enough algal toxins to adversely affect the freshwater shrimps.

The invention also provides an algae resource utilization device applied to the method, which comprises the enclosure net cage and the hydraulic jet mechanism, wherein the hydraulic jet mechanism sprays water to the water body to rotate the water body inside and outside the enclosure net cage so that the algae are gathered towards the inside of the enclosure net cage through the netting of the enclosure net cage.

As an improvement, the enclosure net cage comprises a buoy and a framework, and a netting with 1-5 cm of net holes is sleeved on the buoy and the framework.

As an improvement, the hydraulic jet mechanism is provided with a water pump, and the water pump is positioned at the bottom of the water body and is communicated with the jet pipeline through a hose.

As a further improvement, an inverted cone-shaped net cage with a downward opening is arranged in the enclosure net cage, and the inverted cone-shaped net cage is positioned above the water pump so that the inverted cone-shaped net cage can filter water entering the water pump.

Tests in a river course prove that the water quality around the enclosure net cage is obviously improved by using the method, and particularly after continuous sunny days, the water quality around the enclosure net cage is clearer and all water environment chemical indexes are good.

Drawings

FIG. 1 is a top view of example 1 of the present invention;

FIG. 2 is a side view of example 1 of the present invention;

FIG. 3 is a diagram showing the total phosphorus change of the upstream and downstream of the device after 5 consecutive sunny days in an experimental area; in the figure, the abscissa represents the distance in m; the ordinate represents index value, and the unit is mg/L;

FIG. 4 is a diagram showing the change of total nitrogen upstream and downstream of the device after 5 consecutive sunny days in an experimental area; in the figure, the abscissa represents the distance in m; the ordinate represents index value, and the unit is mg/L;

FIG. 5 is a graph showing the change of total phosphorus in the upstream and downstream of the apparatus after 2 days of continuous sunny days in the experimental area; in the figure, the abscissa represents the distance in m; the ordinate represents index value, and the unit is mg/L;

FIG. 6 is a diagram showing the total nitrogen change of the upstream and downstream of the device after 2 days of continuous sunny day in the experimental area; in the figure, the abscissa represents the distance in m; the ordinate represents the index value in mg/L.

In the figure, 10, a containment net cage; 20. a hydraulic jetting mechanism; 21. a water pump; 22. a hose; 23. a power generation and control device; 24. an underwater cable; 30. an inverted conical net cage; 31. a reinforcing steel bar frame; 32. a rope.

Detailed Description

Example 1

The test site is a certain river section in the east Yangxi Zhejiang lake, the width of the river is 30 meters, and the device 1 set is arranged in the middle of the river. The continuous operation is carried out for 2 years, the surrounding water quality is greatly improved, endogenous water blooms do not occur, the algae composition in the riverway mainly comprises euglena and diatoms, the main riverway is different from the main riverway mainly comprising blue algae, and the blue algae water blooms input by the main riverway can be eliminated within 3 days and cannot exist for a long time.

The specific control method comprises the following steps:

step S10, as shown in figure 1, arranging an enclosure net cage 10 in a water body, wherein the enclosure net cage 10 is a square net cage and is formed by connecting a buoy and a framework, the height of the enclosure net cage 10 is greater than the depth of the water body by 20cm, the outer side size of the enclosure net cage 10 is 4m multiplied by 4m, a netting with a mesh hole of 2cm is sleeved, and the inner side size of the enclosure net cage 10 is 3m multiplied by 3m.

2 fish of carnivorous fish snakeheads (with the specification of 100 g/tail), 3 fish of Wuchang fish (with the specification of 50 g/tail) of herbivorous fish and omnivorous fish, 7 fish of crucian (sucking omnivorous fish) with the specification of 50 g/tail and 3 fish of chub (filter omnivorous fish) with the specification of 100 g/tail are thrown in the enclosure net cage 10. The fish thrown manually can not be completely suitable for changeable environment, wild species are required to play a role, and the water flow and algae in the enclosure net cage 10 are flocculated, so that wild fishes and shrimps can be attracted to grow.

And step S20, the enclosure net cage 10 is provided with a hydraulic jet mechanism 20. The hydraulic jet mechanism 20 uses the center of the enclosure net cage 10 as a circle center, and sprays water in one direction of clockwise or counterclockwise along the tangential direction of the circle, so that the water inside and outside the enclosure net cage 10 rotates, and the algae are gathered towards the inside of the enclosure net cage 10 through the netting of the enclosure net cage 10. The hydraulic jet mechanism 20 is a jet pipeline arranged on the inner side of the enclosure net cage 10, a 25cmPPR pipe is connected into a 2m multiplied by 2m square frame, and the jet pipeline is provided with holes so that the surface of the water body rotates when the jet pipeline sprays water to the water body. The hydraulic jet mechanism 20 is started, the hydraulic jet mechanism 20 promotes the surface of the water body to flow, so that the exchange speed of the water body inside and outside the enclosure net cage 10 is accelerated, and the algal bloom is intercepted by the netting part of the enclosure net cage 10 when flowing through the meshes of the enclosure net cage 10 along with the exchange of the water body.

As shown in fig. 2, the water for injection from the injection pipe originates from the bottom of the body of water. The jet pipeline is connected with a water pump 21 through a hose 22, the water pump 21 is placed at the bottom of the enclosure box 10, the water pump 21 is driven by a power generation and control device 23, and the power generation and control device 23 is communicated with the water pump 21 through an underwater cable 24. An inverted cone-shaped net cage 30 with the bottom of 1m multiplied by 1m is arranged in the enclosure net cage 10, and the inverted cone-shaped net cage 30 is positioned above the water pump 21 so that the inverted cone-shaped net cage 30 can filter the water body entering the water pump 21. The height of the inverted conical net cage 30 is 50cm. The top of the inverted cone-shaped net cage 30 is positioned 50cm under water, the opening of the inverted cone-shaped net cage 30 faces downwards, the size of the opening is 1m multiplied by 1m, and the inverted cone-shaped net cage 30 is provided with a netting with 10 meshes. The top of the inverted cone-shaped net cage 30 is fixed on the water surface by a floating ball, the four corners of the opening are provided with reinforcing steel bar frames 31 as pendants, and the netting is connected by a rope 32.

In step S30, the growth rate curve of the organism from small to large is similar to the logistic curve, and when the growth rate of a certain body is reduced, the assimilation efficiency of nutrient substances is reduced, and the body needs to be replaced by the body with high growth rate. In the experiment, 1.5kg of snakehead, 0.8kg of Wuchang fish, 0.6kg of crucian carp and 2.5kg of bighead carp are harvested and supplemented with young fishes. In the experimental process, the macrobrachium nipponensis with different sizes and strong mobility are gathered in the enclosure net cage 10. But the other areas in the river channel have little freshwater shrimp activity, which indicates that the system creates a livable environment for the freshwater shrimps.

In 2020, the inventor tests the water quality of the upstream and downstream of the test area.

After 5 days of continuous sunny day and 5 days of continuous sunny day in 11 months of 5 days, the total phosphorus change of the upstream and downstream of the device is shown in fig. 3, the abscissa is 0, the position of the center of the device is shown, the left side of the point 0 represents the upstream of the device, the right side of the point 0 represents the downstream of the device, the 5 on the left side of the point 0 represents an upstream water taking point 5m away from the edge of the device, and the 5 on the right side of the point 0 represents a downstream water taking point 5m away from the edge of the device. As can be seen from FIG. 3, the total phosphorus concentration was 0.12mg/L at positions 5m and 20m upstream of the apparatus and 0.08mg/L within 30m downstream of the apparatus. The total nitrogen change of the water body on the upstream and downstream of the device after 5 days on a continuous sunny day is shown in figure 4, and the total nitrogen concentration is kept even lower than the concentration of the central position of the device within the range of 30m above and below the device.

After 24 days in 5 months and 2 days in a continuous sunny day, the change of the total phosphorus of the upstream and downstream of the device is shown in figure 5, and the total phosphorus concentration in the area of about 30m between the upstream and downstream of the device is obviously greater than the value of 5 days in a continuous sunny day. Similar to 5 consecutive sunning days, the total phosphorus concentration downstream of the plant is lower than the total phosphorus concentration upstream of the plant. The change of the total nitrogen of the water body on the upstream and downstream of the device after 2 days of continuous sunny days is shown in fig. 6, the total nitrogen concentration is kept in a relatively low range within the range of 20m above and below the device, and the value is close to the value of 5 days of continuous sunny days. Indicating that the effect of total phosphorus is more sensitive to an extended exposure time.

As can be seen from comparison between fig. 3 and 6, the longer the number of days in a continuous sunny day, the greater the range of influence of the apparatus on water quality. Because the photosynthesis of healthy algae is enhanced along with the increase of sunshine hours, so that the healthy algae has more obvious function as a primary producer in the water body, the material flow of a food chain formed by organisms inside and outside the device is enhanced, the biological groups are diffused to the surrounding to a larger extent, and the influence range of the system is increased.

Claims

1. The algae resource utilization method for algae bloom prevention and control is characterized by comprising the following steps: comprises the following steps of (a) carrying out,

s10, arranging a plurality of enclosure net cages (10) provided with hydraulic jet mechanisms (20) in a water body, wherein the height of the enclosure net cages (10) is greater than the depth of the water body, and feeding carnivorous fishes, herbivorous fishes and omnivorous fishes into the enclosure net cages (10);

step S20, the hydraulic jet mechanism (20) sprays water to the water body to enable the water body inside and outside the enclosure net cage (10) to rotate, so that algae are gathered towards the interior of the enclosure net cage (10) through a net cover of the enclosure net cage (10), and algae cells are mixed with organic debris and soil particles in the water body to generate organic floccules which are then ingested by fish in the enclosure net cage (10);

and step S30, periodically removing the slowly growing fishes in the enclosure net cage (10) to prevent the existing stock of the fishes from being too large, and supplementing juvenile fishes.

2. The method for resource utilization of algae for algal bloom control as set forth in claim 1, wherein: the hydraulic jet mechanism (20) takes the center of the enclosure net cage (10) as a circle center and sprays water along the circular tangential direction, so that water inside and outside the enclosure net cage (10) rotates.

3. The method for resource utilization of algae for algal bloom control according to claim 1, wherein: the hydraulic jet mechanism (20) is a jet pipeline arranged on the inner side of the enclosure net cage (10), and the jet pipeline sprays water to a water body through an opening on the jet pipeline.

4. The method for resource utilization of algae for algal bloom control according to claim 1, wherein: one or more of shrimps, crabs, shellfish and native fishes are put into the enclosure net cage (10).

5. The method for resource utilization of algae for algal bloom control as set forth in claim 4, wherein: the shrimps put into the enclosure net cage (10) are freshwater shrimps.

6. The algae resource utilization device applied to the method according to claim 1, wherein: the algae collecting device comprises an enclosure net cage (10) and a hydraulic jet mechanism (20), wherein the height of the enclosure net cage (10) is larger than the depth of a water body, and the hydraulic jet mechanism (20) sprays water to the water body to rotate the water body inside and outside the enclosure net cage (10) so that algae are gathered towards the inside of the enclosure net cage (10) through a net cover of the enclosure net cage (10).

7. The apparatus for resource utilization of algae for algal bloom control according to claim 6, wherein: the enclosure net cage (10) comprises a buoy and a framework, and a netting with 1 cm-5 cm mesh holes is sleeved on the buoy and the framework.

8. The algae resource utilization device for algal bloom control according to claim 6, wherein: the hydraulic jet mechanism (20) is a jet pipeline arranged on the inner side of the enclosure net cage (10), and the jet pipeline sprays water to a water body through an opening on the jet pipeline.

9. The algae resource utilization device for algal bloom control according to claim 8, wherein: the hydraulic jet mechanism (20) is provided with a water pump (21), and the water pump (21) is positioned at the bottom of the water body and is communicated with the jet pipeline through a hose (22).

10. The algae resource utilization device for algal bloom control according to claim 9, wherein: an inverted cone-shaped net cage (30) with a downward opening is arranged in the enclosure net cage (10), and the inverted cone-shaped net cage (30) is located above the water pump (21) to enable the inverted cone-shaped net cage (30) to filter water entering the water pump (21).