CN107117715B

CN107117715B - Ecological restoration system for lake and reservoir desilting

Info

Publication number: CN107117715B
Application number: CN201710124352.1A
Authority: CN
Inventors: 杜河清; 彭瑜; 雷勇; 高龙华; 谢龙; 林枫
Original assignee: Guangzhou Zhuke Academy Of Engineering Survey And Design Co Ltd; Pearl River Hydraulic Research Institute of PRWRC
Current assignee: Guangzhou Zhuke Academy Of Engineering Survey And Design Co Ltd; Pearl River Hydraulic Research Institute of PRWRC
Priority date: 2017-03-03
Filing date: 2017-03-03
Publication date: 2020-03-27
Anticipated expiration: 2037-03-03
Also published as: CN107117715A

Abstract

The invention discloses a post-desilting ecological restoration system for lakes and reservoirs, which comprises an artificial floating island arranged on a water body, a sand cushion layer arranged on the bottom surface of the lakes and reservoirs, a plurality of microorganism units and microorganism generators, wherein the microorganism units and the microorganism generators are arranged in the water body; the microorganism unit is arranged on the sand cushion layer. The ecological restoration system after lake and reservoir desilting is simple in construction, can quickly improve water quality, adjust and restore ecological balance, can restore the ecological system of the desilted lake and reservoir, and is remarkable in water quality improvement effect, long in maintenance time and low in cost.

Description

Ecological restoration system for lake and reservoir desilting

Technical Field

The invention relates to the technical field of water environment and water ecology, in particular to a post-desilting ecological restoration system for lakes and reservoirs.

Background

The lake eutrophication is a phenomenon that the excessive growth of primary producers is promoted due to the increase of nutrient load, so that the function of the water body is damaged. The eutrophication of lakes is generally characterized by an excessive increase in phytoplankton. The water bloom is one of the typical characteristics of lake eutrophication, and is the centralized embodiment of ecological balance destruction in the eutrophication state of water body, and the phenomenon that the water surface is in abnormal water color such as blue, red, brown, milky white and the like due to the explosive propagation of plankton in the water body. When the water bloom occurs, the algae breed and rot in a large quantity, which causes the fishy smell of the water, reduces the transparency of the water body, influences the dissolution of oxygen in the water body, releases toxic substances into the water body and causes the serious deterioration of aquatic ecology.

The lake is a complete ecosystem consisting of animals, plants and microorganisms. Under normal conditions, all levels of organisms are in a dynamic equilibrium state, and the algae and the aquatic plants in the water body synthesize self organic matters through photosynthesis by using N, P in the water and produce oxygen. The fishes in the water body feed on algae and aquatic plants to control the excessive propagation of the algae. The feces excreted by the aquatic animals and dead bodies of the organisms increase the organic content of the water. The organic nutritive salt is decomposed into inorganic matters under the action of organic mineralized microorganisms, and the inorganic matters are utilized by algae and aquatic plants. This creates a matter circulation of the ecosystem that is in dynamic equilibrium when there is less flux of matter (N, P) in the circulation.

On the contrary, when a large amount of nutrient salts such as N, P exist in the water body, the sufficient sunlight, the proper temperature and the large amount of nutrient salts provide good conditions for the growth and the propagation of the algae. The transparency of the water body is seriously reduced due to the mass propagation of algae, submerged aquatic plants die due to insufficient sunlight, the water body is layered due to the massive floating of algae, the dead algae and settled organic matters are decomposed in the lower water body to cause insufficient dissolved oxygen, and fishes and aerobic microorganisms die due to the rapid consumption of the dissolved oxygen in the water. Meanwhile, a large amount of dead biological residues and organic matters in water are converted into various toxic substances (such as hydrogen sulfide, organic acid, ammonia nitrogen and the like) under the anaerobic condition, the death rate of other organisms is increased due to the existence of the substances, and finally the original substance circulation is broken, so that the whole ecological system is unbalanced and falls into the vicious circle.

Dredging is an effective and rapid method for removing deposited nutrients, which is essential in the long term. Meanwhile, sediment dredging is a double-edged sword, and disturbance of the sediment dredging on the ecology of the lake bottom is reflected in reduction of the total amount of pollutants, and certain negative effects can be generated on the ecosystem of the lake.

The negative effects of dredging include:

1. during dredging, the mechanical agitation can cause bottom sand to be suspended, and during sludge transfer, the silt scattered in water can cause turbidity of local water areas. Meanwhile, the stirring can cause the suspension of bottom mud pollutants, release ammonia nitrogen and phosphide, and lead the water quality to be "fattened", so that the dredging can not achieve the water quality improvement and the expected effect.

2. Physical, chemical and biological conditions of the original surface layer sludge of the sediment are changed after dredging, and the change of the environmental factors can change the original nutrient salt release balance of a sediment-water interface, so that N, P in the fresh sediment is released at an accelerated speed, and the concentration of the nutrient salt in the water body is increased. Neeberg et al found that the nascent surface layer readily released dissolved phosphorus (SOP) over time increased over that before dredging by a simulated dredging experiment. Graca et al found that there was a greater accumulation of organic matter, total nitrogen and total phosphorus in the newly formed surface layer in the Puck bay dredging zone of the polo sea than in the non-dredging zone. The phosphorus release flux of the desilting area is 7 times that of the non-desilting area.

3. The original ecological environment of the lake bottom can be damaged by dredging, so that microorganisms and aquatic animals and plants in the lake disappear, the ecological chain is fragile, and the self-purification capacity of the water body completely disappears. After sediment is desilted, the benthic ecosystem is completely destroyed, once the ecosystem established in years or even decades is destroyed, the ecosystem is difficult to repair and rebuild, and after sediment is completely desilted and before a new benthic ecosystem is established, the whole river channel ecosystem is fragile and is easy to burst into water bloom and other conditions. Such as dredging of river channels by Beijing at the end of the 20 th century and dredging of basalt lakes by Nanjing at the beginning of the 21 st century, large-scale bloom events are subsequently developed. Under the condition, the water bloom is very easy to burst, and the phenomena of N, P sudden rising and water bloom occurrence appear in a short period after dredging and leading the water into the basalt lake of Nanjing, the fruit lake of Wuhan and the external sand lake. The total area of the Dian pond is nearly 300km²Billions of yuan are spent for 2-3 years (1997-1998), and only partial area of bottom mud is dug in the grass sea, which accounts for about 1% of the total area of the Dian pond. The quality of the water after dredging is already in the beginning of the world's BoThe measured grass sea transparency is 0-20 cm, and the chlorophyll a is up to 938mg/m³The algae amount is 1952g/m³Serious blue algae flooding still occurs.

Therefore, the restoration of the micro-ecology of the water body after the lake dredging becomes very important and is indispensable for the prognosis maintenance of the water quality of the water body.

Disclosure of Invention

The invention aims to provide a post-desilting ecological restoration system which has a good restoration effect and can be maintained for a long time.

The technical scheme adopted by the invention for solving the technical problems is as follows: the ecological restoration system comprises an artificial floating island arranged on a water body, a sand cushion layer arranged on the bottom surface of the lake reservoir, a plurality of microorganism units and microorganism generators, wherein the microorganism units and the microorganism generators are arranged in the water body; the microorganism unit is arranged on the sand cushion layer.

Preferably, the artificial floating island comprises a floating island body, a plant layer and a biological membrane carrier; the floating island body is arranged on the water surface in a floating mode, the plant layer is planted above the floating island body, and the biomembrane carrier is hung below the floating island body and is located below the water surface.

Preferably, the floating island body is made of polyethylene plastic;

the biological membrane carrier is a carbon fiber carrier or a hollow fiber carrier.

Preferably, the covering thickness of the sand cushion layer is 10-30 cm.

Preferably, the microorganism unit comprises a culture carrier and a strain arranged on the culture carrier;

the strain comprises one or more of bacillus, actinomycetes, fungi, nitrodenitrifying bacteria, phosphorus accumulating bacteria and pseudomonas; the culture carrier comprises a microorganism culture substrate and sandy soil.

Preferably, the microorganism unit also comprises high-efficiency composite algae control enzyme matched with the strain; the high-efficiency composite algae-controlling enzyme comprises algae-dissolving enzyme and microcystin degrading enzyme.

Preferably, the microbial generator comprises a microporous ceramic canister and a microbial matrix; the microbial matrix is arranged in the microporous ceramic tank body.

Preferably, the post-desilting ecological restoration system for the lake reservoir further comprises a bank protection device arranged in the water body along the bank.

Preferably, the revetment means comprises gabions.

Preferably, the microbial generator is disposed in the gabion.

The invention has the beneficial effects that: the construction is simple, the water quality can be rapidly improved, the ecological balance can be adjusted and restored, the ecological system of the desilted lake and reservoir can be restored, the water quality improvement effect is obvious, the maintenance time is long, and the cost is low.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic cross-sectional view of a post-desilting ecological restoration system for lakes and reservoirs according to an embodiment of the present invention;

fig. 2 is a schematic structural view of the gabion and the microbial generator in fig. 1.

Detailed Description

For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

The post-desilting ecological restoration system for the lake reservoir is arranged in the desilted lake reservoir to carry out ecological restoration on the post-desilting ecological restoration system. The lake and reservoir cover water body environments such as lakes, reservoirs, riverways and the like.

As shown in fig. 1, the ecological restoration system after lake reservoir desilting according to an embodiment of the present invention includes an artificial floating island 10 disposed on a water body, a sand cushion 20 disposed on the bottom surface of the lake reservoir, a microorganism unit 30 disposed in the water body, and a microorganism generator 40; the microbial cells 30 are disposed on the sand cushion 20.

The artificial floating island 10 is arranged on the water body, plays a certain role in purifying water quality, and can be used as a place for fish living in lakes and reservoirs, a living space for birds and the like. The overall size of the artificial floating island 10 can be specifically set according to the area of the lake or the reservoir.

In this embodiment, the artificial floating island 10 is a wet floating island. Specifically, the artificial floating island 10 may include a floating island body 11, a plant layer 12, and a biofilm carrier 13; the floating island body 11 floats on the water surface, the plant layer 12 is planted above the floating island body 11, and the biomembrane carrier 13 is hung below the floating island body 11 and is positioned below the water surface.

The floating island body 11 is made of materials which can float in water, such as polyethylene plastics. The plant layer 12 is planted above the floating island body 11, and the specific plant species is not limited and can be determined according to the lake and reservoir water body and the ecological environment thereof. The biomembrane carrier 13 is arranged below the floating island body 11 and is soaked in water, a biomembrane is formed on the surface, and microorganisms in the membrane can phagocytose and metabolize pollutants in water into inorganic matters to purify water quality.

The biofilm carrier 13 can be carbon fiber carrier or hollow fiber carrier.

The number of the biofilm carriers 13 is not limited and may be determined according to the distribution range thereof. Alternatively, a plurality of biofilm carriers 13 are hung below the floating island body 11, and the plurality of biofilm carriers 13 are arranged at intervals. Taking the length (height perpendicular to the water body) of the biofilm carriers 13 as 1.5-2m as an example, the interval between two adjacent biofilm carriers 13 can be 0.2 m.

The sandstone cushion 20 covers the bottom surface of the lake and reservoir and can be used as a cushion for replacing sludge before dredging. The thickness of the sand bed 20 covered on the bottom of the lake is mainly determined by the dredging amount, and can be 10-30cm in general.

The microorganism unit 30 is fixed on the surface of the sandstone cushion layer 20, and provides a plurality of bacteria for the dredged water body so as to balance the bacteria in the water body. The plurality of microorganism units 30 are distributed on the sandstone cushion layer 20 at intervals, and the interval between the adjacent microorganism units 30 is 2m, or the interval is increased or decreased according to the actual situation.

The microorganism unit 30 includes a culture carrier and a seed culture disposed on the culture carrier. The culture carrier comprises a microorganism culture substrate, sandy soil and a clay mixture; the clay mixture (which may include clay and ferrous salts) provides a flocculating and settling effect on the suspended matter. The bacterial species may include one or more of bacillus, actinomycetes, fungi, nitrobacter, phosphorus accumulating bacteria, pseudomonas and the like. Wherein, the bacillus, the actinomycetes, the denitrifying bacteria, the phosphorus-accumulating bacteria and the like can effectively reduce the concentration of nutrients in the water body and the sediment and continuously improve the water quality; the nitrifying and denitrifying bacteria can effectively reduce the concentration of ammonia nitrogen and total nitrogen in the water body; the phosphorus accumulating bacteria can reduce the total phosphorus concentration in the water body.

Generally, the strains are algae-controlling microorganisms; the algae-controlling microorganism can promote the activity of beneficial algae in the water body, improve the ability of the beneficial algae to compete for the restrictive nutrient elements with the blue-green algae in the water body, and enable the beneficial algae to become a dominant population in the water body, thereby reducing the proliferation speed of the blue-green algae and achieving the purposes of controlling and removing the algae. Beneficial algae such as chlorella can be used as primary producers of water, and the photosynthesis of the beneficial algae can release a large amount of oxygen, provide a high dissolved oxygen environment for aquatic animals, promote the further restoration of the water ecology and simultaneously provide a large amount of high-nutrition baits for the aquatic animals.

The algae-controlling microorganisms can also secrete algae-dissolving active substances, can inhibit the reformation of algae, gradually improve the transparency of the water body and effectively ensure the clearness of the water body.

Further, the microorganism unit 30 may also include a high-efficiency composite algae-controlling enzyme for cooperating with the strain; the high-efficiency composite algae-controlling enzyme comprises algae-dissolving enzyme and microcystin degrading enzyme. The high-efficiency composite algae-controlling enzyme can supplement with algae-controlling microorganism algae-controlling enzyme to provide a proper environment for the survival and growth of the algae-controlling microorganism algae-controlling enzyme, so that the nutrient substances in the water body can be effectively decomposed, and the existence of the algae-controlling enzyme can scrap harmful algae and organic matters in the environment around the cells into nutrient substance types which can be easily absorbed and absorbed by the algae-controlling microorganism.

The microbial generator 40 comprises a microporous ceramic tank and a microbial matrix; the microbial matrix is arranged in the microporous ceramic tank body and provides conditions for the generation of microorganisms. The microbial generator 40 is mainly a microbial generator that generates ammoniated bacteria; the ammonifying bacteria comprise anaerobic bacteria and aerobic bacteria, can adapt to various natural environments, effectively decompose nitrogenous organic compounds to release ammonia, and can finally convert organic decomposition products into NH4⁺。

Further, the ecological restoration system after desilting the lake reservoir of the present invention further includes a bank protection device 50 disposed on the bank of the lake. The bank protection device 50 is arranged in the water along the bank and plays a role of reinforcing the bank after dredging.

The revetment apparatus 50 is preferably positioned in the lower half of the body of water and may be exposed to the water during dry periods and below the body of water during rich periods.

The revetment apparatus 50 comprises gabions, a plurality of which are connected side by side to form the integral revetment apparatus 50. The gabion can be of a cubic structure with the size of 1m by 1m, and the carrying and the connection are convenient.

The gabion has the advantages of economy, simplicity and quickness in construction, low cost and the like, has strong capability of resisting natural damage, corrosion and adverse weather influence, can bear large-scale deformation without collapse, has good permeability, and can prevent damage caused by hydrostatic force.

As shown in fig. 2, in the present embodiment, the microbial generator 40 is disposed in the gabion, which can play a role of stabilizing the microbial generator 40, and can also form a biofilm on the stones of the gabion, so that the stones of the gabion become a carrier structure of the microbial film.

The ecological restoration system for the desilted lakes and reservoirs is simple in construction, capable of quickly adjusting and improving ecological balance, capable of carrying out ecological restoration on the desilted lakes and reservoirs, remarkable in effect, long in duration and low in cost.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A post-desilting ecological restoration system for lakes and reservoirs is characterized by comprising an artificial floating island arranged on a water body, a sand cushion layer arranged on the bottom surface of the lakes and reservoirs, a plurality of microorganism units and a microorganism generator which are arranged in the water body; the sand-stone cushion layer is used as a cushion layer for replacing sludge before dredging; the microorganism unit is arranged on the gravel cushion layer and provides multiple bacteria for the desilted water body so as to balance the bacteria in the water body;

the artificial floating island comprises a floating island body, a plant layer and a biological membrane carrier; the floating island body floats on the water surface, the plant layer is planted above the floating island body, the biomembrane carrier is hung below the floating island body and is positioned below the water surface, a biomembrane is formed on the surface, and microorganisms in the biomembrane phagocytose and metabolize pollutants in the water into inorganic substances; the floating island body is made of polyethylene plastic; the biological membrane carrier is a carbon fiber carrier or a hollow fiber carrier;

the microorganism unit comprises a culture carrier and a strain arranged on the culture carrier; the strain comprises one or more of bacillus, actinomycetes, fungi, nitrodenitrifying bacteria, phosphorus accumulating bacteria and pseudomonas; the culture carrier comprises a microorganism culture substrate and sandy soil;

the microbial generator is used for generating ammoniated bacteria and comprises a microporous ceramic tank body and a microbial matrix, wherein the microbial matrix is arranged in the microporous ceramic tank body and provides conditions for the generation of microorganisms.

2. The post-desilting ecosystem of a lake according to claim 1, wherein the sand blanket is covered to a thickness of 10-30 cm.

3. The post-lake desilting bioremediation system of claim 1, wherein the microorganism unit further comprises a high efficiency composite algaecide enzyme that is coordinated with the bacterial species; the high-efficiency composite algae-controlling enzyme comprises algae-dissolving enzyme and microcystin degrading enzyme.

4. A post-desilting ecological remediation system for a lake reservoir according to any one of claims 1 to 3, further comprising a bank protection device disposed in the body of water along a bank.

5. The post-desilting ecological restoration system for a lake reservoir of claim 4, wherein the bank protection device comprises gabion.

6. The post-desilting ecosystem of a lake according to claim 5, wherein the microbial generator is disposed in the gabion.