CN109179857B

CN109179857B - Eutrophic water body remediation method based on ecological isolation, fish remediation, substrate phosphorus locking and plant capture

Info

Publication number: CN109179857B
Application number: CN201810422256.XA
Authority: CN
Inventors: 杨扬; 王赛; 李凤; 王林; 龙胜兴
Original assignee: Jinan University
Current assignee: Jinan University
Priority date: 2018-05-04
Filing date: 2018-05-04
Publication date: 2022-01-07
Anticipated expiration: 2038-05-04
Also published as: CN109179857A

Abstract

The invention discloses a eutrophic water body remediation method based on ecological isolation, fish remediation, substrate phosphorus locking and plant capture. Firstly, carrying out ecological isolation on a water body with high nutrient salt content, an algae enrichment area or a polluted water area, then removing native fishes which can cause water body disturbance, then carrying out disinfection treatment on the water body in the enclosure, spraying a phosphorus locking agent to ensure the transparency of the water body and reduce the endogenous release of phosphate in substrate, and then rebuilding an aqueous ecological system taking an aquatic plant community as a core, reducing the nutrient salt content in the eutrophic water body, controlling the level of algae and suspended particles and preventing the outbreak of algal bloom by relying on the strong absorption capacity of submerged, emergent and floating plants. The method has extremely high stability after restoration, can maintain high transparency of the water body for a long time, ensures that aquatic plants grow vigorously and endogenous nutrient salts in the substrate are blocked, ensures that an aquatic ecosystem is in a perfect autonomous circulation state, and achieves the aims of nitrogen and phosphorus nutrient salt grab and water quality improvement in the algae-rich area.

Description

Eutrophic water body remediation method based on ecological isolation, fish remediation, substrate phosphorus locking and plant capture

Technical Field

The invention relates to the technical field of ecological restoration, in particular to a eutrophic water body restoration method based on ecological isolation, fish restoration, substrate phosphorus locking and plant grab.

Background

The rapid development of economy and the continuous increase of population cause a large amount of nutrient substances to continuously flow into lakes, so that the eutrophication phenomenon of the lakes becomes more and more serious, and the eutrophication phenomenon becomes a worldwide ecological environment problem and influences the sustainable development of local society and economy. Therefore, the research on the degradation mechanism and the control technology of the eutrophic water ecological system has very important theoretical and practical significance. The large-scale aquatic plant is used for enriching nitrogen and phosphorus, which is one of effective ways for treating, adjusting and inhibiting water eutrophication. The large-scale aquatic plants have strong capability of enriching nitrogen and phosphorus; the limited light energy in the eutrophic water body can be utilized, and the dissolved oxygen can be added to the water body; meanwhile, the method can also provide food sources, habitats and other necessary conditions for the formation of a complex food chain, and is the basis for maintaining the biological diversity of the water body.

In recent 10 years, extensive research has been conducted domestically and abroad on the action of aquatic higher plants in lake ecosystems and the restoration thereof, and attempts have been made to convert turbid aquatic water bodies, which take algae as the dominance, into clear aquatic water bodies, which take aquatic higher plants as the dominance. The pioneer, Shapiro, who includes biological regulation also believes that biological regulation must be dominated by the restoration of aquatic higher plants to maintain a clear water lake ecosystem. Many studies have shown that higher aquatic plants can maintain a water body stable in a clear state for a long period of time. The long-term stability is required to be kept after biological regulation, the total phosphorus concentration is less than 0.10mg/L, and the submerged plants play an important role in stabilizing the clear water state and can be used as a switch for switching between the turbid water state and the clear water state and a buffer for maintaining the clear water state.

However, many factors are often used in the construction or reconstruction of submerged plants to purify water or to perform water ecological restoration works. The low transparency of eutrophic water is one of the main stresses for the survival of aquatic higher plants, and the aquatic higher plants, especially submerged plants, cannot obtain enough light energy to grow due to the low transparency of the water and insufficient underwater illumination. In addition, research indicates that algae can also inhibit the growth of aquatic higher plants, and particularly cyanobacterial algal blooms in eutrophic water bodies have fatal damage to the aquatic higher plants. Aiming at the problems of increasing the content of nutritive salt, frequent algal blooms, reducing biodiversity and the like in the water body, which are generally existed at present, the problems are difficult to solve by adopting a single treatment measure, and meanwhile, the combination of multiple water quality improvement technologies becomes a great trend of the treatment of the damaged water body. Practice proves that establishing a stable aquatic ecosystem mainly comprising aquatic plants is an effective measure for treating the still water body, and the ecological restoration of the damaged water body by adopting the method also becomes a hotspot of water environment treatment research at home and abroad.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings of the prior art and provide a method for restoring eutrophic water based on ecological isolation, fish restoration, substrate phosphorus locking and plant grab, which mainly aims at the problems of endogenous release, algae enrichment and water quality deterioration caused by overhigh nutrient salt concentration of still water bodies such as ponds, lakes, reservoirs and the like.

The above object of the present invention is achieved by the following technical solutions:

a eutrophic water body remediation method based on ecological isolation, fish remediation, substrate phosphorus locking and plant capture comprises the following steps:

s1, performing ecological isolation on a water body of a region to be restored by adopting a waterproof material to isolate the water body in an enclosure from the water body outside the enclosure;

s2, thoroughly cleaning the fishes in the enclosure;

s3, disinfecting the water body and the substrate of the area to be repaired, spreading a phosphorus locking agent into the water body, and trapping phosphate in the substrate;

s4, constructing an ecological community taking aquatic plants as cores in the area to be restored; wherein emergent aquatic plants are planted on the bank slope, submerged plants are planted in the open water area, and floating-leaf plants are planted along the bank zone.

The invention firstly carries out ecological isolation on the water body with high nutrient salt content, the algae enrichment area or the polluted water area, then removes the native fishes which can cause water body disturbance so as to prevent the release of endogenous nutrient salt and the re-suspension of particles caused by the disturbance of sediment by the fishes, then carries out disinfection treatment on the water body in the enclosure, and sprays the phosphorus-locking agent to carry out adsorption and sedimentation treatment on the soluble phosphate in the water body so as to ensure the transparency of the water body and reduce the endogenous release of the phosphate in the sediment. The core content of the invention lies in reconstructing an aquatic ecosystem taking an aquatic plant community as a core, reducing the content of nutrient salt in the eutrophic water body, controlling the level of algae and suspended particles and preventing the outbreak of algal bloom by relying on the strong absorption capacity of submerged plants, emergent plants and floating-leaf plants. The method has extremely high stability after restoration, can maintain high transparency of the water body for a long time, ensures that aquatic plants grow vigorously and endogenous nutrient salts in the substrate are blocked, ensures that an aquatic ecosystem is in a perfect autonomous circulation state, and achieves the aims of nitrogen and phosphorus nutrient salt grab and water quality improvement in the algae-rich area.

Preferably, S1 specifically includes the following steps:

s11, making an enclosure: selecting rubber enclosures with the properties of wear resistance, sunlight resistance, corrosion resistance, water impermeability and the like, wherein each section is 10m long, a float valve is arranged on each rubber enclosure, a counterweight binding rope is arranged below each rubber enclosure, and steel cable joints are arranged at two ends of each rubber enclosure so as to conveniently connect the sectional enclosures into a whole;

s12, manufacturing a gabion: sewing a polyethylene net into a long cylindrical bag with the diameter of 10cm, wherein the length of the bag is 10m, pouring gravel and sewing a net opening, placing the bag at the bottom end of each enclosure to be used as a pull-down counterweight, and matching 2 gabions with each enclosure;

s13, placing an enclosure: the enclosure is lifted to a designated position by a plurality of people, and the waterproof cloth at the bottom end connecting part of the enclosure provided with the gabion is pressed into the mud by adopting a mode of manually treading and piling up sandbags, so that a large amount of obvious water seepage is avoided;

s14, fixing an enclosure: fixing steel piles are driven at positions 5m away from the water surface on the shore at two ends of the enclosure, the depth is 2m underground, 2 steel piles are driven in water at intervals of 1m, the steel piles are transversely spaced at intervals of 2m, the depth is 2-3 m below a substrate, the enclosure is bound among the 2 steel piles through nylon ropes, sand bags are piled at the connecting positions of the enclosure and the shore, and water body exchange inside and outside the enclosure is reduced;

s15, peripheral blocking: and a barrier net is arranged outside the enclosure, and the barrier net is made of phytoplankton nets with the aperture of 0.064mm and blocks algae and suspended particulate matters.

Wherein, the enclosure is arranged on the outer layer to play the roles of resisting wind waves, blocking exogenous pollution and preventing bottom fishes from entering. The nylon screen with the aperture of 0.064mm placed outside the enclosure can intercept algae and particles on one hand, and can prevent fishes from being far away from the restoration area on the other hand, so that bottom mud in the restoration area is prevented from being disturbed by the fishes.

Preferably, the method for cleaning fish as described in S2 is artificial driving, trapping or electric pulse fishing. Firstly expelling the original fishes to the outside of the enclosure by manual driving, then collecting the rest fishes by adopting a fixed shrimp cage trapping and sinking type triple-flow gill net capturing mode, and finally ensuring that no fish residue exists in the enclosure; and finally, fishing by adopting electric pulse to remove fish (such as the goby) with too small body size and fish larvae (juvenile fish of tilapia, silver carp and the like).

Preferably, the spraying amount of the phosphorus-locking agent S3 is about 125g/m²And keeping the water body standing for 48 hours after spraying. Can be specifically adoptedAnd uniformly spraying the repairing area by using a diesel pump type sprayer.

Preferably, the S4 slope planting emergent aquatic plants are specifically planted in a gradient manner at the slope by selecting canna, arundo donax, reed and verduria, and the planting sequence from the water surface to the bank is verduria, canna, arundo donax and reed in sequence.

Preferably, the submerged plants planted in the S4 open water area are planted in the whole pond by taking the eel grass and the hydrilla verticillata with strong pollution resistance as pioneer seeds in the first stage; and (3) encrypting and replanting the submerged plants with good growth, constructing a long-acting submerged plant community, and transplanting the submerged plant community according to the principle of sparse deep water areas and dense shallow water areas.

Preferably, S4 coastal zone planting floating-leaf plants are specifically planting watery green foxtail algae and water lily in coastal shallow water areas, the planting needs to be planted in groups by bamboo baskets so as to form a group propagation effect, and the water lily is planted in small areas in a collective manner.

Compared with the prior art, the invention has the following beneficial effects:

the method disclosed by the invention is developed by taking large-scale aquatic plant restoration as a core, the higher transparency of the water body can be maintained by early work, the interference of other organisms, particularly fishes, is reduced, the release of endogenous nutritive salt in the substrate is controlled, and the aquatic plant restoration process can be finished in a favorable environment. In addition, the method disclosed by the invention is extremely high in stability after restoration, can maintain a clear water body and a bottom, enables aquatic plants to grow normally, is low in release amount of endogenous nutrient salts in the bottom, realizes the autonomous circulation function of a water body ecological system, and achieves the purposes of nitrogen and phosphorus nutrient salt grab and water quality improvement in an algae-rich area. The ecological restoration technology has the advantages of low cost investment and operating cost, simple structure of ecological treatment facilities and the like, and has important popularization and application values in the technical field of water ecological restoration.

Drawings

FIG. 1 is a schematic diagram of steps of the eutrophic water restoration method of the present invention.

Fig. 2 is the plane of the water body remediation zone of the wild goose pond of example 1.

Fig. 3 shows the enclosure plane design and field installation effect of the present invention.

FIG. 4 shows the process of spraying the phosphorus-locking agent (A-B-C-D).

FIG. 5 shows the submerged plant growing process (A-B-C-D).

Fig. 6 is a bank slope emergent aquatic plant growing area.

Fig. 7 is a comparison of the appearance of a body of water before remediation (A, B) and after remediation (C, D, E).

Detailed Description

The invention is further described with reference to the drawings and the following detailed description, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

Example 1

Selecting white mud pit bay at the tail of Yantian reservoir as an ecological restoration demonstration area (figure 2), wherein the total area of the demonstration area is about 10200m²(170 m in length and 60 m in width) and the average depth of the water body is 1.7m, and the demonstration area is processed in a partition mode and comprises three test areas, wherein the area of the area I is 1200m²Area of II region 6000m²Zone III area 3000m². And (4) performing water body remediation according to the steps shown in figure 1.

First, repair method

1. Ecological isolation of water body in algae-rich area

In order to ensure that no external pollution enters a repair area, a PVC (polyvinyl chloride) material is firstly adopted for enclosing and separating, and the mode of 'sandbag + piling + steel rope' is adopted for fixing, so that the water body separation of a non-demonstration area is realized. The field operation process is shown in fig. 3, and comprises the following specific steps:

(1) manufacturing an enclosure: PVC enclosures with the properties of wear resistance, sunlight resistance, corrosion resistance, water impermeability and the like are selected, each section is 10m long, a float valve is arranged on the PVC enclosures, a counterweight binding rope is arranged below the PVC enclosures, and the tail end of a PVC material is provided with a steel cable joint so as to conveniently connect the segmented enclosures into a whole;

(2) manufacturing a gabion: sewing a polyethylene net into a long cylindrical bag with the diameter of 10cm, wherein the length of the bag is 10m, pouring gravel and sewing a net opening, placing the bag at the bottom end of each enclosure to be used as a pull-down counterweight, and matching 2 gabions with each enclosure;

(3) placing an enclosure: the enclosure is lifted to a designated position by a plurality of people, and the waterproof cloth at the bottom end connecting part of the enclosure provided with the gabion is pressed into the mud by adopting a mode of manually treading and piling up sandbags, so that a large amount of obvious water seepage is avoided;

(4) fixing an enclosure: fixing steel piles are driven at positions 5m away from the water surface on the shore at two ends of the enclosure, the depth is 2m underground, 2 steel piles are driven in water at intervals of 1m, the steel piles are transversely spaced at intervals of 2m, the depth is 2-3 m below a substrate, the enclosure is bound among the 2 steel piles through nylon ropes, sand bags are piled at the connecting positions of the enclosure and the shore, and water body exchange inside and outside the enclosure is reduced;

(5) peripheral blocking: and a barrier net is arranged outside the enclosure, and the barrier net is made of phytoplankton nets with the aperture of 0.064mm and blocks algae and suspended particulate matters.

The PVC enclosure is arranged on the outer layer, and plays roles in resisting wind waves, blocking exogenous pollution and preventing bottom fishes from entering. The nylon screen with the aperture of 0.064mm is placed outside the enclosure, so that algae and particles can be intercepted, on the one hand, the effect of preventing fishes from being far away from the restoration area can be achieved, and the bottom mud in the restoration area is guaranteed not to be disturbed by the fishes.

2. Removing native fish in enclosure

Firstly, expelling original fishes to the outside of the enclosure in a manual expelling mode, then collecting the rest fishes in a standing shrimp cage trapping and sinking type triple-flow gill net capturing mode, and finally ensuring that no fish residues exist in the enclosure; and finally, fishing by adopting electric pulse to remove fish (such as the goby) with too small body size and fish larvae (juvenile fish of tilapia, silver carp and the like).

3. Sterilizing and dephosphorizing water body and geology

After cleaning the wild trash fish, disinfecting the water body and the sediment substrate, removing potential pathogenic microorganism flora, and putting 200kg of substrate disinfectant into use. 25 bags (50 kg/bag) of the Phoslock of the Australia indigenous research and development material are purchased, the soluble phosphate in the water body of the demonstration area is subjected to adsorption and sedimentation treatment, and the phosphate is locked in the substrate sediment after sedimentation, so that the endogenous phosphate is prevented from being released again, the content of the nutritive salt in the water body is reduced, and the occurrence of algal blooms is prevented.

4. Constructing a plant community ecosystem taking aquatic plants as cores

Emergent aquatic plants are planted on the bank slope, submerged plants are planted in the open water area, and floating-leaf plants are planted along the bank zone.

The coastal zone floating-leaf plants are selected from the watermifoil and water lily. The watermifoil is planted in groups by bamboo baskets, so that the watermifoil can form a group propagation effect, the water lily is planted in a small range and is concentrated into pieces, and about 50 pieces are planted in a demonstration area. Emergent aquatic plants are planted in the range of 4m from the water surface on the bank slope and are planted in batches in 4 plant strips, the first strip is emerald, the second strip is canna, the third strip is giant reed, the fourth strip is reed, and the width of each plant strip is 1 m. The number of plants which can be planted in the width range depends on the size of each plant, the number of the green Philippine plants is small, 8-10 plants can be planted in the range of 1m, the number of canna plants is large, 3-4 plants can be planted in the range of 1m, and 5-7 plants can be planted in the giant reed and the reed.

Planting the submerged plants by adopting a method of throwing seconds and planting the tape grass and the hydrilla verticillata in the demonstration area. The submerged plant is planted into two stages, wherein in the first stage, hydrilla verticillata and eel grass with strong pollution resistance are used as pioneer seeds to be planted in the whole pond; and in the second stage, the submerged plants with good growth are planted in an encrypted and replanting mode, a long-acting submerged plant community is constructed, and the principle that a deep water area is sparse and a shallow water area is dense is followed when the submerged plant community is transplanted. The planting mode is as follows: the shallow water area can adopt artificial underwater transplanting type planting, and the planting is firstly sparse and then dense; for the deep water area which is inconvenient for manual launch planting, a bamboo pole inserting second method can be adopted, 1 person can paddle, 1 person can plant and insert, the planting is carried out lightly, the bamboo pole is inserted into the soil by about 10cm, and the top of the grass is aligned with the water surface.

Second, result in

After the method is implemented, the field monitoring result shows that the water quality and the eutrophication condition of the test area are obviously improved (figure 7 and table 1), indexes such as nitrogen, phosphorus, chlorophyll, suspended matters and the like in the water body are reduced by 30-60%, wherein the total phosphorus content is 0.05mg L^-1The chlorophyll content is less than 15 μ g L^-1。

TABLE 1 comparison of Water quality indicators before and after remediation

Claims

1. A eutrophic water body remediation method based on ecological isolation, fish remediation, substrate phosphorus locking and plant capture is characterized by comprising the following steps:

s2, thoroughly cleaning the fishes in the enclosure;

s4, constructing an ecological community taking aquatic plants as cores in the area to be restored; wherein emergent aquatic plants are planted on the bank slope, submerged plants are planted in the open water area, and floating-leaf plants are planted along the bank zone;

s3 the phosphorus-locking agent is sprayed in an amount of about 125g/m²Keeping the water body standing for 48 hours after spraying;

s4 the method comprises the steps of selecting canna, arundo donax linn, reed and verdure to carry out gradient planting on the bank slope, wherein the planting sequence from the water surface to the bank is the order of verdure, canna, arundo donax linn and reed;

s4 submerged plants planted in the open water area are specifically planted in the whole pond by taking eel grasses and hydrilla verticillata with strong pollution resistance as pioneer seeds in the first stage;

in the second stage, the submerged plants with good growth are planted in an encrypted and replanting manner, and a long-acting submerged plant community is constructed;

s4 planting floating-leaf plants in coastal zone is to plant Pinus-green foxtail algae, water lily, and foxtail algae in shallow water zone.

2. The method according to claim 1, wherein S1 specifically comprises the steps of:

s11, making an enclosure: selecting a rubber enclosure which has wear resistance, sunlight resistance, corrosion resistance and water tightness, wherein each section is 10m long, a float valve is arranged on the rubber enclosure, a counterweight binding rope is arranged below the rubber enclosure, and steel cable joints are arranged at two ends of the enclosure so as to connect the sectional enclosures into a whole conveniently;

s15, peripheral blocking: the outer side of the enclosure is provided with a blocking net which is made of phytoplankton nets with the aperture of 0.064mm and blocks algae and suspended particles.

3. The method according to claim 1, wherein the method of cleaning fish of S2 is artificial driving, trapping or electric pulse fishing.