Shore-based jet aeration and air floatation coupled ecological ditch algae removal and water purification process

Abstract

The invention belongs to the field of water treatment, and particularly relates to a shore-based jet aeration and air floatation coupled ecological ditch algae removal and water purification process. According to the process, the common advantages of jet aeration air floatation and the ecological ditch are combined, algae blooms are eliminated, and the water body is purified. According to the process, oxygenation of a water body and air flotation removal of algae are achieved through jet aeration, the algae base number in the water body is reduced, and the algae bloom phenomenon can be effectively inhibited or rapidly eliminated; in addition, the water body nutrient salt concentration can be reduced, the water body eutrophication is inhibited, the water body power is increased, and the ecological diversity and landscape value of the water body are improved while the water body is kept clean for a long time; the process is suitable for landscape pools, lakes, rivers and other surface water bodies, the implementation mode is simple, the manufacturing cost and the maintenance cost are low, and the high application and popularization value is achieved.

Description

Technical Field

[0001] The present invention relates to the field of water treatment, and specifically relates to a shore-based jet aeration and flotation coupled with an ecological ditch for algae removal and water purification process. Background Art

[0002] The increasingly serious pollution of water bodies, the excessive input of nutrients such as nitrogen and phosphorus, climate change, the physical properties of water bodies (pH value, dissolved oxygen, light penetration depth, etc.), fluidity, benthic sediments, the health status of the ecosystem, etc. are all the reasons for the growth of algae in surface water bodies and even the outbreak of algal blooms. The problem that algal blooms are easy to generate but difficult to eliminate has long been one of the most challenging environmental problems in the management of lakes and rivers worldwide.

[0003] In the treatment of algal blooms, many methods or strategies have been developed, including reducing nutrient input, biological manipulation (such as introducing filter-feeding fish), physical methods (water replacement, water regulation and control, filtration, etc. technologies), chemical methods (adding oxidizing agents, such as copper sulfate, chlorine preparations, quaternary ammonium salts, etc.), and advanced technical means (such as remote sensing monitoring and early warning systems for algal bloom outbreaks). Although these methods have achieved certain results to a certain extent, there are still many problems. For example, reducing nutrient input often takes a long time to show results. Especially for large and medium-sized water bodies, it is unrealistic to reduce nutrient salts; physical and chemical intervention methods will bring great side effects, such as the poisoning of aquatic organisms and the water ecosystem. Therefore, how to effectively control the occurrence of algal blooms and eliminate algal bloom phenomena is still an important challenge, and an effective treatment measure still needs to be explored.

[0004] Jet aeration and flotation uses water to carry air and mix air into the water body for flotation. The jet device uses a Venturi nozzle, and countless fine bubbles are formed after spraying. The bubble diameter is small and the residence time in the water body is relatively long. The present invention utilizes the dual advantages of the stirring and oxygenation ability of jet aeration and flotation and the flotation solid-liquid separation effect, and adopts the shore-based jet aeration and flotation algae removal technology to promote the full contact between algae and other substances in the water body and bubbles, effectively reducing the algal base number in water bodies such as lakes or rivers, and controlling the occurrence of algal blooms and eliminating algal bloom phenomena.

[0005] At the same time, the present invention adopts the method of combining jet aeration and flotation with an ecological ditch. While removing algae in the water body, reducing the concentration of water body nutrients, and improving the water quality of the water body, it can also increase the water body dynamics, improve the ecological landscape, and maintain a long-term clear and clean state with clear water and green shores. Summary of the Invention

[0006] In view of the problem of algal bloom treatment, the present invention provides a shore-based jet aeration and flotation coupled with an ecological ditch for algae removal and water purification process.

[0007] The specific technical solution of the present invention is as follows: An onshore jet aeration and air flotation coupled ecological ditch algae removal and water purification process, including a jet aeration and air flotation process and an ecological ditch process. The devices used in the jet aeration and air flotation process include a submersible pump system, a coagulation air flotation system, and an algae collection system; the devices used in the ecological ditch process include a sluice gate, a double-blind pipe, a graded matrix, aquatic plants, and an outlet pipe.

[0008] The submersible pump system in the jet aeration and air flotation process includes a pump pit, arc side plates, a submersible pump, and a floating device. The pump pit is completely below the water body. For easy installation and disassembly, it is preferably made of stainless steel; the height from the top of the pump pit to the water surface is 10 - 20 cm; a set of arc side plates is provided on each of the left and right sides of the top of the pump pit. The main purpose is to collect the algal blooms floating on the water surface of the water body, reduce the inflow of algal turbid water below the water surface of the algal blooms, and thus increase the concentration of algae entering the pump pit and improve the algae removal efficiency of the jet aeration and air flotation process; the arc side plates have a certain slope, and the slope gradually increases downward along the pump pit opening, and the maximum slope is 45°; the material of the arc side plates is preferably stainless steel, and the height of the arc side plates is 1 / 4 - 1 / 3 of the height of the pump pit; the submersible pump is a submersible sewage pump, and the high-concentration algal bloom water body flowing into the pump pit enters the subsequent system from the submersible pump; the floating device is connected to the pump pit to make the pump pit float in the water body, so that the pump pit can collect the algal blooms on the water surface at different water levels.

[0009] The coagulation air flotation system includes a jet aerator, a coagulation air flotation tank, and a chemical dosing device. The coagulation air flotation tank is arranged on the shore of the water body, and the jet aerator is installed around the coagulation air flotation tank. The jet aerators arranged around spray the algal bloom water body dissolved with a large number of microbubbles into the coagulation air flotation tank, realizing the effective contact between the algal bloom particles and the bubbles, and the stirring is sufficient, avoiding the formation of dead zones in the coagulation air flotation tank and effectively improving the coagulation air flotation efficiency. The coagulation air flotation system is arranged on the shore, which is convenient for installation, inspection, and maintenance.

[0010] The chemical dosing device contains a coagulant, mainly to better agglomerate the algal bloom particles in the coagulation air flotation tank and then remove them by air flotation; the coagulant is a conventional inorganic or organic coagulation agent, preferably one or several of polyaluminum chloride, polyaluminum sulfate, polyferric sulfate, and polyacrylamide. Among them, the concentration of the inorganic coagulant in the coagulation air flotation tank is 30 - 60 mg / L, and the concentration of the organic coagulant is 0.5 - 2 mg / L.

[0011] After the algal bloom water body is treated by the coagulation air flotation system, the algal bloom particles floating in the coagulation air flotation tank are collected into the algae collection system. The algae collection system includes an algae transport pipeline and an algae well, and the algae transport pipeline transports the algal bloom particles to the supporting algae well.

[0012] After the water body with algal blooms is treated by the coagulation air flotation system, the water body after coagulation air flotation treatment flows to the subsequent ecological ditch through the overflow weir and the water pipeline. A small amount of algal bloom particles contained in the transported water body are further intercepted by the sluice gate at the front end of the ecological ditch and collected into the adjacent algal well. The depth and size of the algal well can be determined according to the amount of algal blooms in the water body, and the algal bloom particles collected in the algal well can be recycled and treated.

[0013] The ecological ditch is arranged along the water body to be treated. A double-blind pipe is laid at the bottom of the ecological ditch, plain soil is laid below the double-blind pipe, and graded matrix is laid above it. The graded matrix includes large-particle matrix and small-particle matrix. The large-particle matrix includes one or more of crushed stones, cobblestones, and porous fillers, with a particle size of 8 - 16 mm; the small-particle matrix includes one or more of volcanic rocks, zeolites, biological ceramsites, and coarse quartz sands, with a particle size of 3 - 8 mm; aquatic plants are planted on the top of the small-particle matrix. The aquatic plants are common emergent plants, preferably one or several of Thalia dealbata, Iris tectorum, Pontederia cordata, Typha orientalis, and Phragmites australis.

[0014] A plurality of water outlet pipes are arranged on the double-blind pipe, facilitating the treated water in the ecological ditch to be discharged back to the original water body nearby, increasing the water body dynamics and realizing the effective treatment of the original water body.

[0015] The beneficial effects of the present invention are as follows: The process described in the present invention combines the common advantages of jet aeration air flotation and ecological ditch to eliminate algal blooms and purify the water body. This process can realize the high-density collection and air flotation removal of algae in the water body by using the jet aeration air flotation process, effectively reducing the algal base number in water bodies such as lakes or rivers, inhibiting the occurrence of algal blooms or eliminating algal bloom phenomena, and restoring the clarity of the water body; in addition, this process couples with the ecological ditch to further remove suspended solids, nitrogen, phosphorus and other pollutants in the water body after jet aeration air flotation treatment, inhibits water eutrophication and increases water body dynamics, and restores and maintains the clarity of the water body. This process has a high algae removal efficiency, effectively reduces the concentration of water pollutants, inhibits water eutrophication and algal bloom outbreaks, has no secondary pollution, is green and environmentally friendly, improves the ecological diversity and landscape value of the water body, is applicable to surface water bodies such as landscape ponds, lakes, and rivers, has a simple implementation method, low construction cost and maintenance cost, and has high popularization and application value. Description of the Drawings

[0016] Figure 1 Schematic diagram of an onshore jet aeration air flotation coupled ecological ditch algae removal and water purification process Figure 2 Plan view of an onshore jet aeration air flotation coupled ecological ditch algae removal and water purification process Reference Signs

[0017] Pump pit; 2 - Arc side plate; 3 - Submersible pump; 4 - Floating device; 5 - Jet aerator; 6 - Coagulation - flotation tank; 7 - Chemical dosing device; 8 - Micro - bubbles; 9 - Algal bloom particles; 10 - Overflow weir; 11 - Water pipeline; 12 - Algae pipeline; 13 - Algae well; 14 - Ecological ditch; 15 - Gate plate; 16 - Double - blind pipe; 17 - Plain soil; 18 - Large - particle substrate; 19 - Small - particle substrate; 20 - Aquatic plants; 21 - Outlet pipe Detailed implementation mode

[0018] A shore - based jet aeration - flotation coupled ecological ditch algae - removal and water - purification process includes a jet aeration - flotation process and an ecological ditch process. The devices used in the jet aeration - flotation process include a submersible pump system, a coagulation - flotation system, and an algae collection system; the devices used in the ecological ditch process include a gate plate 15, a double - blind pipe 16, graded substrates, aquatic plants 20, and an outlet pipe 21.

[0019] The submersible pump system includes a pump pit 1, arc side plates 2, a submersible pump 3, and a floating device 4. The pump pit 1 is completely below the water level. For easy installation and disassembly, it is preferably made of stainless steel; the height from the top of the pump pit 1 to the water surface is 10 - 20 cm; a set of arc side plates 2 is arranged on each of the left and right sides of the top of the pump pit 1. The main purpose is to collect the algal blooms floating on the water surface of the water body, reduce the inflow of algae - turbid water below the water surface of the algal bloom, and thus increase the algae concentration entering the pump pit 1 and improve the algae - removal efficiency of the jet aeration - flotation process; the arc side plates 2 have a certain slope, and the slope gradually increases along the opening of the pump pit 1 downward, and the maximum slope is 45°; the material of the arc side plates 2 is preferably stainless steel, and the height of the arc side plates 2 is 1 / 4 - 1 / 3 of the height of the pump pit 1; the submersible pump 3 is a submersible sewage pump, and the high - concentration algal bloom water body entering the pump pit 1 enters the subsequent system from the submersible pump 3. Among them, the installation quantity of the submersible pump 3 in the pump pit 1 is specifically determined according to the algal bloom amount in the water body; the floating device 4 is connected to the pump pit 1 to make the pump pit 1 float in the water body, so that the pump pit 1 can collect the algal blooms on the water surface at different water levels.

[0020] The coagulation - flotation system includes a jet aerator 5, a coagulation - flotation tank 6, a chemical dosing device 7, and an overflow weir 10. The coagulation - flotation tank 6 is arranged on the shore of the water body, and the jet aerators 5 are installed around the coagulation - flotation tank 6. The jet aerators 5 arranged around spray the algal bloom water body dissolved with a large number of micro - bubbles 8 into the coagulation - flotation tank 6, realizing the effective contact between the algal bloom particles 9 and the bubbles, and stirring fully, avoiding the formation of dead zones in the coagulation - flotation tank, and effectively improving the coagulation - flotation efficiency. The coagulation - flotation system is arranged on the shore, which is convenient for installation, inspection, and maintenance.

[0021] The dosing device 7 contains a coagulant, which is mainly used to better agglomerate the algae bloom particles 9 in the coagulation flotation tank 6 and then flotate and remove them; the coagulant is a conventional inorganic or organic coagulant, preferably one or more of polyaluminium chloride, polyaluminium sulfate, polyferric sulfate and polyacrylamide. The concentration of the inorganic coagulant in the coagulation flotation tank is 30-60 mg / L, and the concentration of the organic coagulant is 0.5-2 mg / L.

[0022] After the algae bloom water body is treated by the coagulation and flotation system, the algae bloom particles 9 floating in the coagulation and flotation tank 6 are collected into the algae collection system. The algae collection system includes an algae transport pipeline 12 and an algae well 13. The algae transport pipeline 12 can transport the algae bloom particles 9 to the matching algae well 13.

[0023] After the algae bloom water body is treated by the coagulation and flotation system, the water body treated by coagulation and flotation flows to the rear ecological ditch 14 through the overflow weir 10 and the water pipeline 11. A small amount of algae bloom particles 9 contained in the water body are further intercepted by the gate plate 15 at the front end of the ecological ditch 14 to the caisson 13 next to it. The depth and size of the caisson 13 can be determined according to the algae bloom concentration of the water body, and the algae bloom particles 9 collected in the caisson 13 can be recycled.

[0024] The ecological ditch 14 is set along the water body to be treated, and a double blind pipe 16 is laid at the bottom of the ecological ditch 14, and a plain soil 17 is laid below the double blind pipe, and a graded matrix is ​​laid above. The graded matrix includes a large particle matrix 18 and a small particle matrix 19, and the large particle matrix 18 includes one or more of crushed stones, pebbles, and porous fillers, and the particle size is 8-16 mm; the small particle matrix 19 includes one or more of volcanic rock, zeolite, biological ceramsite, and coarse quartz sand, and the particle size is 3-8 mm; the top of the small particle matrix 19 is planted with aquatic plants 20, which are common emergent plants, preferably one or more of the following: iris, sedge grass, cattail, and reed.

[0025] The double-blind pipe 16 is equipped with a plurality of outlet pipes 21, so that the effluent after further treatment in the ecological ditch 14 can be discharged back to the original water body nearby, thereby increasing the water body dynamics and realizing the effective treatment of the original water body. Example 1

[0026] The process described in the present invention is used to purify a landscape lake water body with an area of ​​about 30 mu and an average water depth of 1.8 m. Due to the high nutrient content and other reasons, the water quality of the water body is inferior to Class V, with low transparency and algae cell density of 10 8cells / L, and severe water bloom phenomena occur in this water body during spring and summer. The process described in the present invention is used to purify this water body. In this process, the height from the top of the pump pit to the water surface is 10 cm, the height of the arc side plate is 1 / 4 of the pump pit height, the concentration of inorganic coagulant in the coagulation flotation tank is 60 mg / L, the concentration of organic coagulant is 2 mg / L, the large particle matrix includes crushed stones and cobblestones with a particle size of 8 mm; the small particle matrix includes volcanic rock, zeolite, biological ceramsite, and coarse quartz sand with a particle size of 3 mm; there are 5 kinds of aquatic plants, namely Thalia dealbata, Iris tectorum, Pontederia cordata, Typha orientalis, and Phragmites australis, planted on the top of the small particle matrix. The water quality, algal cell density, transparency and other indicators of this water body are monitored for a long time, and the average results of the water quality of this water body within half a year are shown in Table 1. Example 2

[0027] The process described in the present invention is used to purify the water body of a certain section of river. The length of this river is about 8 km, the average width is about 2.5 m, and the average water depth is about 1.0 m. Due to reasons such as external pollution, the water quality of this water body is inferior to Class V, the transparency is low, and the algal cell density reaches 10 7 cells / L, and obvious water bloom phenomena occur in this water body during spring and summer. The process described in the present invention is used to purify this water body. In this process, the height from the top of the pump pit to the water surface is 20 cm, the height of the arc side plate is 1 / 3 of the pump pit height, the concentration of inorganic coagulant in the coagulation flotation tank is 30 mg / L, the concentration of organic coagulant is 0.5 mg / L, the large particle matrix includes crushed stones and cobblestones with a particle size of 16 mm; the small particle matrix includes volcanic rock, zeolite, biological ceramsite, and coarse quartz sand with a particle size of 8 mm; there are 3 kinds of aquatic plants, namely Thalia dealbata, Iris tectorum, and Pontederia cordata, planted on the top of the small particle matrix. The water quality, algal cell density, transparency and other indicators of this water body are monitored for a long time, and the average results of the water quality of this water body within half a year are shown in Table 2.

[0028] In Example 1 and Example 2, the process described in the present invention is used to remove algae and purify different surface water bodies. The water quality of the water body can be significantly improved. The concentrations of COD, TN, ammonia nitrogen, and nitrate nitrogen can reach the Class IV standard and above specified in the "Surface Water Environment Quality Standard" (GB3838-2002). The water purification effect is good, and the algal cell density of the water body can be significantly reduced, the algae bloom phenomenon can be inhibited and eliminated, the transparency of the water body can be greatly improved, and finally the long-term clarification state of surface water bodies such as rivers and lakes can be achieved, further enhancing their ecological value, and having high popularization and application value. The above does not constitute a limitation to the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process, characterized by: The devices used in the process include a jet pump system, a coagulation flotation system, and an algae collection system; the jet pump system includes a pump pit (1), an arc side plate (2), a jet pump (3), and a floating device (4); the coagulation flotation system includes a jet aerator (5), a coagulation flotation tank (6), a dosing device (7), and an overflow weir (10); After the algae bloom water body is treated by the coagulation and flotation system, the algae bloom particles (9) floating in the coagulation and flotation tank (6) are collected into an algae collection system; the algae collection system comprises an algae transport pipeline (12) and an algae well (13); The water body after the coagulation and flotation treatment flows through the overflow weir (10) and the water pipeline (11) to the rear ecological ditch (14), and the ecological ditch (14) includes a gate plate (15), a double blind pipe (16), a graded matrix, aquatic plants (20), and an outlet pipe (21).

2. A shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 1, characterized in that: The pump pit (1) is completely located below the water body, the height of the top of the pump pit (1) from the water surface is 10 to 20 cm, and a set of arc side panels (2) are respectively arranged on the left and right sides of the top of the pump pit 1.

3. A shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 1, characterized in that: The arc side plate (2) has a certain slope, and the slope gradually increases downward along the mouth of the pump pit (1), and the maximum slope is 45°; the material of the arc side plate (2) is preferably stainless steel, and the height of the arc side plate (2) is 1 / 4 to 1 / 3 of the height of the pump pit (1).

4. A shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 1, characterized in that: The coagulation flotation tank (6) is arranged at the bank of a water body, and the jet aerator (5) is installed around the coagulation flotation tank (6). The jet aerator (5) sprays algae bloom water containing a large number of microbubbles (8) into the coagulation flotation tank (6).

5. The shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 1, characterized in that: The coagulant in the dosing device (7) includes an inorganic coagulant and an organic coagulant; the concentration of the inorganic coagulant in the coagulation flotation tank (6) is 30-60 mg / L, and the concentration of the organic coagulant is 0.5-2 mg / L.

6. A shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 5, characterized in that: The inorganic coagulant includes one or more of polyaluminium chloride, polyaluminium sulfate and polyferric sulfate, and the organic coagulant includes polyacrylamide.

7. The shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 1, characterized in that: The algae bloom particles (9) floating in the coagulation flotation tank (6) are transported to the matching caisson (13) via the algae transport pipeline (12). The water transport pipeline (11) transports a small amount of algae bloom particles (9) contained in the water body and further intercepts them through the gate plate (15) at the front end of the ecological ditch (14) to the caisson (13) nearby. The algae bloom particles (9) collected in the caisson (13) can be recycled.

8. The shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 1, characterized in that: The ecological ditch (14) is arranged along the water body to be treated, a double blind pipe (16) is laid at the bottom of the ecological ditch (14), plain soil (17) is laid below the double blind pipe, and a graded matrix is ​​laid above the double blind pipe.

9. The shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process as claimed in claim 1, characterized in that: The graded matrix comprises a large particle matrix (18) and a small particle matrix (19), wherein the large particle matrix (18) comprises one or more of crushed stones, pebbles, and porous fillers, and has a particle size of 8 to 16 mm; the small particle matrix (19) comprises one or more of volcanic rock, zeolite, biological ceramsite, and coarse quartz sand, and has a particle size of 3 to 8 mm; aquatic plants (20) are planted on the top of the small particle matrix (19), and the aquatic plants (20) are emergent plants, preferably one or more of lily of the valley, iris, pickerel grass, cattail, and reed.

10. The shore-based jet aeration and flotation coupled ecological ditch algae removal and water purification process according to claim 1, characterized in that: The double-blind pipe (16) is equipped with a plurality of outlet pipes (21), and the effluent from the ecological ditch (14) after further treatment is discharged back to the original water body nearby through the outlet pipes (21).

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