A method for simultaneous degradation of sediment pollutants and water purification suitable for black and odorous water body

Abstract

This invention discloses a method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies, belonging to the field of water environment management technology. The method includes the following steps: Step S1, water pretreatment and micro-disturbance of bottom sediment; Step S2, in-situ decomposition treatment of bottom pollutants; Step S3, stratified purification treatment of overlying water; Step S4, ecological stabilization and long-term maintenance. This invention employs the above-mentioned method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies. It is applicable to black and odorous water bodies of varying pollution levels, such as urban rivers, ditches, and small enclosed lakes, and can achieve simultaneous decomposition of endogenous pollutants in bottom sediment and purification of overlying water, balancing short-term odor control and long-term ecological stability.

Description

Technical Field

[0001] This invention relates to the field of water environment treatment technology, and in particular to a method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies. Background Technology

[0002] Black and odorous water bodies are a typical manifestation of water pollution in the process of urbanization. The core cause is that the input of pollutants exceeds the self-purification capacity of the water body, forming a vicious cycle of "pollution-oxygen deficiency-ecological damage": excessive accumulation of organic matter in the water body leads to dissolved oxygen (DO) below 2 mg / L. After entering an anaerobic state, it produces malodorous substances such as hydrogen sulfide and ammonia nitrogen. At the same time, a large amount of organic matter, heavy metals and other pollutants accumulate in the bottom sediment, becoming an endogenous source of pollution, further aggravating the black and odorous water body, destroying the aquatic ecosystem, and affecting the quality of life of residents.

[0003] Currently, the treatment of black and odorous water bodies mostly adopts a combined model of "source control and interception + physical dredging + chemical oxygenation + biological remediation". However, there are many technical bottlenecks: First, physical dredging easily disturbs the bottom sediment, causing pollutants to spread and causing secondary pollution. Moreover, the cost of disposing of bottom sediment after dredging is high, and it cannot fundamentally eliminate pollutants inside the bottom sediment. Second, chemical agents (such as calcium peroxide or ozone alone) can only achieve short-term oxygenation or water quality improvement. They cannot act on the bottom sediment and water body simultaneously, and they are prone to secondary pollution, making it difficult to achieve long-term treatment. Third, biological remediation technologies (such as the application of single bacterial agents or the planting of aquatic plants) have problems such as unstable microbial colonization, low pollutant degradation efficiency, and poor synergistic purification effect between bottom sediment and water body, which makes it easy for black and odorous phenomena to recur after treatment.

[0004] Existing technologies, while some attempts to combine physical, chemical, and biological techniques, are mostly step-by-step processes, failing to achieve simultaneous and synergistic treatment of sediment pollutants and water purification. Furthermore, they suffer from drawbacks such as long treatment cycles, high costs, and poor ecological compatibility, thus failing to meet the needs for efficient and long-term treatment of black and odorous water bodies with varying degrees of pollution. Therefore, developing a technological solution that can simultaneously achieve in-situ decomposition of sediment pollutants and purification of overlying water, while possessing practicality, long-term effectiveness, and eco-friendliness, has become an urgent need in the field of black and odorous water body treatment. Summary of the Invention

[0005] The purpose of this invention is to provide a method for the simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies. This method can achieve the simultaneous decomposition of endogenous pollutants in bottom sediment and purification of the overlying water body, taking into account both short-term odor control and long-term ecological stability.

[0006] To achieve the above objectives, the present invention provides a method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies, comprising the following steps: Step S1: Water pretreatment and sediment micro-disturbance. Eliminate floating objects and large debris on the water surface. Based on the water depth and sediment topography, finely arrange microfluidic aeration devices for shallow aeration. At the same time, arrange low-frequency micro-disturbance devices according to the sediment texture to micro-disturb the sediment surface layer of 0-15cm. Step S2: In-situ digestion treatment of bottom pollutants. A slow-release composite digestion agent is added to the surface of the bottom sediment using a combination of bottom sediment surface injection and shallow spraying. After addition, the sediment is continuously disturbed by a low-frequency micro-disturbance device. The slow-release composite digestion agent is composed of a slow-release oxidant, a local composite microbial agent, a modified adsorbent, and a slow-release carrier compounded in a certain mass percentage. The preparation, loading process, storage and transportation requirements of each component are clearly defined. Step S3: Layered purification treatment of the overlying water body. While the pollutants in the bottom sediment are being dissolved in step S2, a composite flocculant is added to the middle layer of the water body and stirred and flocculated. An anti-interference ecological floating bed is laid on the surface of the water body and a biofilm carrier is suspended. Step S4: Ecological stabilization and long-term maintenance. Add benthic organisms to the water body according to the established timing, ratio and method. Add diluted local compound bacterial agent in stages. Regularly test water quality and sediment indicators and adjust treatment parameters. Design parameters and coping principles for extreme working conditions such as rainfall / flood season, high temperature / low temperature, high salinity / high turbidity. When dissolved oxygen in water When any of the following conditions are met: ammonia nitrogen > 1.5 mg / L, total phosphorus > 0.3 mg / L, sulfide > 0.1 mg / L, or pH < 6.5 or > 8.5, the microfluidic aeration and oxygen supplementation will be automatically activated, and 10-20% of local compound microbial agent will be added.

[0007] Preferably, in step S1, the microfluidic aeration device uses microporous aeration heads with a pore size of 50~100μm, arranged in a matrix with a spacing of 0.5~1.0m, and the water disturbance amplitude during aeration is ≤5cm. The aeration intensity of the microfluidic aeration device is dynamically adjusted according to the following formula: ; The aeration intensity is 0.8~1.2m. 3 / (m 2 •h), the aeration time is 2~3h; the aeration heads are arranged according to the water depth H: when H<1m, they are arranged at 0.3~0.5m underwater; when H≥1m, they are arranged in layers at 0.5m and 0.8m underwater; the spacing between aeration heads in the bottom mud shallows and silt pits is set at 0.5m, and mobile aeration units are added in the aeration dead corners; The low-frequency micro-disturbance device is an underwater low-frequency vibrator, positioned 10-15 cm above the surface of the bottom sediment; the optimal disturbance frequency of the low-frequency disturbance device is calculated using the following formula: ; The disturbance frequency is 10~15Hz, the disturbance time is 30~45min, and the micro-disturbance range is 0~15cm of the bottom sediment surface; in, This refers to the real-time aeration intensity; The baseline aeration intensity; Dissolved oxygen in stage S1 Target value, ; Real-time dissolved oxygen in water bodies; This is the disturbance correction factor. The values ​​are based on the following criteria: 0.8~0.9 for silt, 1.0~1.1 for a mixture of mud and sand, and 1.1~1.2 for sandy sediment; when the air temperature is ≥30℃. Increase by 0.1, decrease by 0.1 when ≤10℃; The optimal perturbation frequency; The measured concentration of organic matter on the surface of the sediment. The baseline value for slightly polluted and odorous organic matter is [value missing]. ; This represents the depth of sediment disturbance.

[0008] Preferably, in step S2, the dosage of the sustained-release composite digestive agent is calculated according to the following formula: ; in, This refers to the dosage of the digester; This refers to the concentration of sulfides in the sediment. The total concentration of heavy metals in the sediment; This is the pollution correction factor. The values ​​are based on the following criteria: 0.9~1.0 for mildly polluted water bodies, 1.0~1.2 for moderately polluted water bodies, and 1.2~1.3 for severely polluted water bodies. The dosage of the sustained-release compound digester is 200~500g / m³. 2 The mass percentages of each component are as follows: slow-release oxidant 30%~45%, local compound microbial agent 25%~35%, modified adsorbent 20%~30%, and slow-release carrier 5%~10%. The micro-disturbance frequency after addition is 5~8Hz, the duration is 1~2h, and the micro-disturbance is applied to the surface layer of sediment 0~15cm.

[0009] Preferably, the storage and transportation requirements for the slow-release composite digester are as follows: calcium peroxide and ozone slow-release microspheres should be stored separately in sealed containers, with an ambient temperature ≤25℃ and relative humidity ≤60%, and insulated and moisture-proof packaging should be used during transportation; the digester should be prepared and used immediately, and added within 24 hours after preparation; a small amount of thickener should be added during addition to prevent dilution or scouring by water.

[0010] Preferably, the slow-release oxidant is a compound of calcium peroxide and ozone slow-release microspheres in a mass ratio of 3:1 to 2:1; the ozone slow-release microspheres use hydrophobically modified porous starch as a carrier and are loaded with the ozone precursor sodium percarbonate / ozone urea by vacuum adsorption method, with a loading rate ≥30% and a release cycle of 15 to 20 days. The sustained-release carrier is a compound of sodium carboxymethyl cellulose and bentonite, with a ratio of sodium carboxymethyl cellulose to bentonite of 2:1 to 3:1 and a disintegration time of 24 to 48 hours.

[0011] Preferably, the local compound microbial agent is composed of Bacillus, photosynthetic bacteria, and denitrifying bacteria in a mass ratio of 2:1:1, with an effective viable count of ≥60 billion / gram, and the local compound microbial agent is selected from the local environment of the black and odorous water body to be treated; a high-temperature protectant is added under high-temperature conditions, and a low-temperature cold-resistant local compound microbial agent is used under low-temperature conditions; under high-salt conditions, the proportion of Bacillus is increased to 3:1:1, which can quickly colonize and synergistically degrade organic matter, ammonia nitrogen, and total phosphorus in the bottom sediment, while inhibiting the reproduction of anaerobic microorganisms.

[0012] Preferably, the modified adsorbent is an alkali-activated mineral powder modified adsorbent, made from industrial mineral powder and fly ash through alkali activation treatment, used to adsorb heavy metal ions and small molecule organic matter in sediment; the slow-release carrier is a compound of sodium carboxymethyl cellulose and bentonite, with sodium carboxymethyl cellulose: bentonite = 2:1~3:1 and a disintegration time of 24~48h, used to delay the release rate of the effective components in the composite digester.

[0013] Preferably, in step S3, the composite flocculant is composed of polyaluminum chloride (PAC), polyacrylamide (PAM), and modified zeolite in a mass ratio of 5:1:3, with a dosage of 50-100 mg / L. After addition, an underwater push-flow agitator is used for engineered stirring, first rapidly stirring at a speed of 150-200 r / min for 10-15 min, and then slowly stirring at a speed of 80-100 r / min for 30-40 min. The stirring area is enclosed to reduce floc breakage. For high-turbidity water bodies (turbidity > 500 NTU), first add 30~50 mg / L of PAC as a pretreatment flocculant. After the turbidity drops to below 200 NTU, then add this composite flocculant and purifying agent. Steps S2 and S3 are started simultaneously and last for the same duration of 48-72 hours. There is no time interval between sediment decomposition and water purification, thus avoiding secondary release of pollutants.

[0014] Preferably, in step S3, the coverage rate of the ecological floating bed is 15%~25%, the ecological floating bed adopts a modular splicing structure, a counterweight is added to the bottom, and a net to prevent debris from getting tangled is set around it; at least one native aquatic plant among calamus, reed, and foxtail grass is planted on the floating bed; The biofilm carrier is specifically a polyurethane sponge carrier or a coconut shell carbon fiber carrier, with a specific surface area ≥1500m². 2 / m 3 Biofilm formation rate ≥ 20 g / m 2 The biofilm carrier is cleaned of surface suspended matter every 3 months and 30% is replaced every 6 months. A small amount of nutrients is added to the biofilm carrier to promote microbial colonization.

[0015] Preferably, in step S4, the benthic organisms are native snails and clams, and the addition amount is 50~100 ind / m³. 2 Before addition, disinfect by soaking in a 0.5% potassium permanganate solution for 10-15 minutes; the timing of addition is 7 days after flocculation and sedimentation and when the water turbidity is <50 NTU. The ratio of snails to mussels is 3:1, and the addition is done in batches: 50% is added for the first time, and the remaining 50% is added 7 days later. The diluted local compound microbial agent was diluted at a ratio of 1:1000 and applied in stages: once a week for the first two weeks, and once every two weeks for the next two to four weeks, to ensure stable colonization of the microbial community. The water body's DO, COD, ammonia nitrogen, total phosphorus, and bottom sediment organic matter content are tested every two weeks. The micro-aeration intensity and bacterial agent dosage are adjusted according to the test results to ensure that the water body's DO is stable above 4 mg / L and that bottom sediment pollutants are continuously decomposed.

[0016] Preferably, in step S4, the principle for dealing with extreme working conditions is as follows: (1) Rainfall / Flood Season: Add 20%~30% flocculant 1~2 days before rainfall, and increase the aeration intensity to 1.2~1.5m. 3 / (m 2 •h); After the flood season, remove floating debris and test the concentration of pollutants in the bottom sediment. If the concentration exceeds the standard, add 10% to 20% slow-release compound digester. (2) High temperature (≥30℃): Add a high temperature protectant to the local compound microbial agent, reduce the dosage by 10%, and change the aeration to intermittent mode (aeration for 30 minutes every 2 hours). (3) Low temperature (≤10℃): Replace with low temperature resistant local bacteria, increase the dosage of oxidant by 20%, and extend the time of micro-disturbance of bottom sediment to 2~3h; (4) High salt (salinity > 3‰): Screen salt-tolerant native bacterial agents and increase the proportion of Bacillus spores, and add zeolite powder to the modified adsorbent; (5) High turbidity (turbidity > 500 NTU): Add a pretreatment flocculation step to reduce turbidity before proceeding with conventional purification treatment.

[0017] Therefore, the present invention employs the above-mentioned method for simultaneous decomposition of sediment pollutants and water purification in black and odorous water bodies, and the technical effects are as follows: 1) Low-frequency micro-disturbance technology is adopted, which not only avoids secondary pollution caused by violent disturbance of bottom sediment, but also promotes the release of pollutants on the surface of bottom sediment and improves the decomposition efficiency. 2) The slow-release composite digestive agent achieves the synergistic effect of oxidant, bacterial agent and adsorbent through component optimization. It can not only oxidize and degrade recalcitrant organic matter, but also adsorb heavy metals. It can also achieve the biodegradation of pollutants through local bacterial agents. The action period is extended to 15-20 days, which is significantly better than the existing single agent. 3) The combination of water stratification purification with ecological floating beds and biofilm carriers achieves efficient removal of suspended solids and dissolved pollutants, while building a stable micro-ecosystem, solving the problem of repeated black and odorous water bodies after treatment.

[0018] 4) After treatment using this method, the COD removal rate of the water body is ≥75%, the ammonia nitrogen removal rate is ≥80%, and the total phosphorus removal rate is ≥70%; the degradation rate of organic matter on the surface of the bottom sediment is ≥60%, the sulfide removal rate is ≥90%, and the heavy metal stabilization rate is ≥85%.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a flowchart of an embodiment of a method for simultaneous decomposition of sediment pollutants and water purification in black and odorous water bodies according to the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," or similar terms as used in this invention, mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0023] like Figure 1 As shown, this invention provides a method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies, comprising the following steps: Step S1, Water Pretreatment and Sediment Micro-disturbance: Pre-treatment of black and odorous water bodies involves removing floating debris and large pieces of waste from the water surface. Microfluidic aeration devices are then deployed based on the water depth and bottom sediment topography to provide shallow aeration, controlling the aeration intensity at 0.8-1.2m. 3 / (m 2•h), the aeration time is 2~3h, which increases the dissolved oxygen (DO) of the water surface to 2.5~3.5mg / L, breaking the anaerobic environment of the water body; at the same time, low frequency micro-disturbance devices are arranged at 2~3m quincunx intervals, and the disturbance amplitude is adjusted according to the texture of the bottom sediment to micro-disturb the bottom sediment surface (0~15cm), with a disturbance frequency of 10~15Hz and a disturbance time of 30~45min, to avoid the diffusion of pollutants caused by violent disturbance of the bottom sediment, while promoting the release of pollutants on the bottom sediment surface, creating conditions for subsequent decomposition and treatment.

[0024] The microfluidic aeration device uses a microporous aeration head to control the water disturbance amplitude to ≤5cm during aeration, so as to avoid disturbing the deep pollutants in the bottom sediment. The low-frequency micro-disturbance device uses an underwater low-frequency vibrator, which is placed 10~15cm above the bottom sediment surface. A protective net is set up around the device to ensure that the micro-disturbance only acts on the bottom sediment surface and does not cause silt blockage.

[0025] Step S2: In-situ decomposition and treatment of contaminants in sediment: To prepare a slow-release composite digester, calcium peroxide and ozone slow-release microspheres were stored separately in sealed containers and prepared fresh for immediate use. During addition, the composite digester was mixed with water at a mass ratio of 1:5 to form a suspension, a small amount of thickener was added, and the solution was applied using a combination of injection into the sediment surface at a depth of 5-10 cm and shallow spraying, at a concentration of 200-500 g / m³. 2 The appropriate dosage is added to the surface of the sediment. After addition, the surface of the sediment is continuously disturbed by a low-frequency micro-disturbance device (frequency 5~8Hz) for 1~2 hours to ensure that the composite digesting agent is fully mixed with the sediment and to achieve in-situ digestion of sediment pollutants.

[0026] The slow-release oxidant is a compound of calcium peroxide and ozone slow-release microspheres (mass ratio 3:1~2:1), wherein the ozone slow-release microspheres are made of hydrophobically modified porous starch loaded with sodium percarbonate / ozone urea (loading rate ≥30%) by vacuum adsorption method; the local compound bacterial agent is composed of Bacillus, photosynthetic bacteria and denitrifying bacteria in a mass ratio of 2:1:1 (effective viable bacteria count ≥60 billion / gram), all screened from the local environment of the black and odorous water body to be treated; the modified adsorbent is an alkali-activated mineral powder modified adsorbent, made from industrial mineral powder and fly ash as raw materials through alkali activation treatment; the slow-release carrier is a compound of sodium carboxymethyl cellulose and bentonite (2:1~3:1).

[0027] Step S3: Layered purification treatment of the overlying water: While the bottom sediment is being dissolved, the water is being purified in layers, specifically as follows: In the middle layer of the water body (water depth 0.5~1.5m): If the water body is of high turbidity, pretreatment with 30~50mg / L of PAC should be carried out first. After the turbidity drops to below 200NTU, a composite flocculant should be added (dosage 50~100mg / L, PAC:PAM:modified zeolite = 5:1:3). An underwater push-flow agitator should be used for engineered agitation at a combination of rapid agitation (0.8~1.0m / s, 10~15min) and slow agitation (0.3~0.5m / s, 30~40min). The agitation area should be enclosed to allow the pollutants in the water body to fully flocculate and settle.

[0028] Surface water layer (water depth 0~0.5m): Lay modular ecological floating beds (coverage 15%~25%), with counterweights at the bottom of the floating beds and anti-tangling nets around them, and plant calamus, reeds and foxtail grass in a 2:2:1 ratio; suspend polyurethane sponge / coconut shell carbon fiber biofilm carriers under the floating beds, loaded with local compound bacterial agents, and add a small amount of nutrients to the carriers to promote microbial colonization.

[0029] Step S2 and Step S3 are started simultaneously, with a duration of 48~72h.

[0030] Step S4, Ecological Stabilization and Long-Term Maintenance: After the sediment digestion and water purification treatment are completed, and 7 days after flocculation and sedimentation are completed and the water turbidity is <50 NTU, disinfected native snails and mussels (3:1 ratio, total addition of 50-100 ind / m³) are introduced into the water in batches. 2 The initial application of 50% and the subsequent application of the remaining 50% after 7 days will construct a symbiotic system of "plants-benthic organisms-microorganisms". At the same time, a locally derived compound bacterial agent diluted in stages (1:1000, once a week for the first 2 weeks, and once every 2 weeks for the next 2-4 weeks, with the amount added decreasing by 20% each time) will be added to the water to ensure the stable establishment of the microbial community.

[0031] Monitoring is conducted every 3 days for core water quality indicators and every 2 weeks for sediment indicators. If any of the following indicators reach any threshold: DO < 2 mg / L, COD > 50 mg / L, ammonia nitrogen > 1.5 mg / L, total phosphorus > 0.3 mg / L, sulfide > 0.1 mg / L, or pH < 6.5 or > 8.5, aeration and oxygen supplementation will be automatically initiated, and targeted bacterial agents / regulators will be added. The biofilm carrier will be cleaned every 3 months and 30% will be replaced every 6 months.

[0032] In case of extreme conditions such as rainfall / flood season, high / low temperature, high salinity / high turbidity, adjust parameters such as the dosage of the agent, aeration intensity, and disturbance time according to the preset response principles to ensure the treatment effect.

[0033] The specific implementation method is as follows: Example 1: Treatment of mildly polluted water bodies (urban river, DO=1.5mg / L, COD=85mg / L, ammonia nitrogen=12mg / L, bottom sediment organic matter content=35g / kg, water depth 0.8m, silty bottom sediment). The specific steps for treating the problem using the method of this invention are as follows: Step S1: Remove floating debris and large pieces of debris from the water surface. Position the microporous aerator heads 0.4m underwater, spaced 0.8m apart, with a spacing of 0.8m. 3 / (m 2 Shallow aeration at an intensity of ·h) for 2h was carried out to raise the DO of the water surface to 2.5mg / L; the bottom sediment surface (0-15cm) was slightly disturbed for 30min using an underwater low-frequency vibrator (frequency 10Hz).

[0034] Step S2: Prepare a slow-release composite digestion agent (30% slow-release oxidant, 35% local composite microbial agent, 30% modified adsorbent, and 5% slow-release carrier). Take 0.95 g of xanthan gum as a tackifier, and add it at 200 g / m³. 2 The dosage was added by a combination of injection and spraying, followed by micro-disturbance at a frequency of 5Hz for 1 hour to ensure that the digester was fully mixed with the sediment.

[0035] Step S3: Add 50 mg / L of composite flocculant to the middle layer of the water body, and use a push-flow agitator for rapid stirring (0.8 m / s, 10 min) + slow stirring (0.3 m / s, 30 min); lay an ecological floating bed with a coverage of 15% on the surface of the water body, mixed with calamus + reed + foxtail grass in a ratio of 2:2:1, and suspend polyurethane sponge carriers loaded with local composite bacterial agents.

[0036] Step S4: After flocculation and sedimentation for 7 days (water turbidity 45 NTU), snails and mussels are introduced in batches (3:1, 50 ind / m³). 2 Add diluted local compound microbial agent (1:1000) once a week for 4 weeks; test water quality and sediment indicators every 2 weeks and adjust aeration intensity to 0.8-1.0m. 3 / (m 2 ·h).

[0037] After 30 days of treatment, the water's dissolved oxygen (DO) level increased to 4.2 mg / L, COD to 38 mg / L, ammonia nitrogen to 0.9 mg / L, and the organic matter content in the bottom sediment to 8.2 g / kg. The water quality met the Class IV standard of GB 3838-2002, with no black or odorous phenomena, and aquatic plants began to grow normally.

[0038] Example 2: Treatment of moderately polluted water bodies (small enclosed lake, DO=1.0mg / L, COD=130mg / L, ammonia nitrogen=18mg / L, bottom sediment organic matter content=52g / kg, water depth 1.2m, mud and sand mixed bottom sediment, high temperature conditions in summer). The specific steps for treating the problem using the method of this invention are as follows: Step S1: Remove floating debris and large pieces of debris from the water surface. Arrange microporous aerators in layers at depths of 0.5m and 0.8m underwater, with a spacing of 1.0m in the mud-sand mixing zone and 0.5m in the shallow water zone, with a spacing of 1.0m between each layer. 3 / (m 2 Shallow aeration at an intensity of ·h) for 2.5h was carried out to increase the DO of the water surface to 3.0mg / L; the bottom sediment surface (0-15cm) was slightly disturbed for 40min using an underwater low-frequency vibrator (frequency 12Hz).

[0039] Step S2: Preparation of a slow-release composite digestion agent (38% slow-release oxidant, 30% local composite microbial agent, 27% modified adsorbent, 5% slow-release carrier). Take 0.95%), add trehalose as a high-temperature protectant to the local microbial agent, reduce the dosage by 10%, and use 350g / m³. 2 The dosage was applied using a combination of injection and spraying, followed by a slight disturbance at a frequency of 6Hz for 1.5 hours.

[0040] Step S3: Add 75 mg / L of composite flocculant to the middle layer of the water body and use a push-flow mixer for rapid stirring (0.9 m / s, 12 min) + slow stirring (0.4 m / s, 35 min); lay an anti-interference ecological floating bed with a 20% coverage on the surface of the water body, mixed with calamus + foxtail algae + reeds in a ratio of 2:2:1, suspend coconut shell carbon fiber carrier and load local composite bacterial agent, and add a small amount of glucose to the carrier.

[0041] Step S4: After flocculation and sedimentation for 7 days (water turbidity 40 NTU), snails and mussels are introduced in batches (3:1, 75 ind / m³). 2 ); add diluted bacterial agent in stages (reducing the dosage by 10%) for 5 weeks; switch aeration to intermittent mode (aeration for 30 minutes every 2 hours), test water quality indicators every 3 days and bottom sediment indicators every 2 weeks, and adjust the aeration intensity to 1.0-1.2m based on the results. 3 / (m 2 ·h).

[0042] After 60 days of treatment, the water's dissolved oxygen (DO) level increased to 4.5 mg / L, COD to 42 mg / L, ammonia nitrogen to 1.1 mg / L, and the organic matter content in the bottom sediment to 11.3 g / kg. The water quality met the Class IV standard of GB 3838-2002, the water transparency increased to 1.0 m, the risk of cyanobacterial blooms was eliminated, and benthic organisms were able to survive normally.

[0043] Example 3: Treatment of severely polluted and odorous water bodies (urban ditches, DO=0.6mg / L, COD=190mg / L, ammonia nitrogen=25mg / L, bottom sediment organic matter content=78g / kg, water depth 1.0m, sandy bottom sediment, high turbidity conditions, turbidity 600NTU). The specific steps for treating the problem using the method of this invention are as follows: Step S1: Remove floating debris and large pieces of debris from the water surface. Arrange microporous aerators in layers at depths of 0.5m and 0.8m, with a spacing of 0.5m, and then at 1.2m intervals. 3 / (m 2 Shallow aeration at an intensity of ·h) for 3h was carried out to raise the DO of the water surface to 3.5mg / L; the bottom sediment surface (0-15cm) was slightly disturbed for 45min using an underwater low-frequency vibrator (frequency 15Hz).

[0044] Step S2: Prepare a slow-release composite digestion agent (45% slow-release oxidant, 25% local composite microbial agent, 25% modified adsorbent, and 5% slow-release carrier). Take 1.25), at 500g / m 2 The dosage was added by a combination of injection and spraying, followed by micro-disturbance at a frequency of 8Hz for 2 hours to ensure that the digester was fully mixed with the bottom sediment.

[0045] Step S3: First, add 40 mg / L of PAC to the middle layer of the water for pretreatment. After the turbidity is reduced to 180 NTU, add 100 mg / L of composite flocculant and purifier. Use a push-flow agitator for rapid stirring (1.0 m / s, 15 min) + slow stirring (0.5 m / s, 40 min). Lay an anti-interference ecological floating bed with a coverage of 25% on the surface of the water. Mix reeds + foxtail grass + calamus = 2:2:1, suspend polyurethane sponge carrier and load local composite bacterial agent.

[0046] Step S4: After flocculation and sedimentation for 7 days (water turbidity 35 NTU), snails and mussels are introduced in batches (3:1, 100 ind / m³). 2 Add diluted bacterial agent in stages for 6 weeks; test water quality indicators every 3 days and bottom sediment indicators every 2 weeks, and adjust aeration intensity and bacterial agent dosage according to the results; clean the biofilm carrier every 3 months.

[0047] After 90 days of treatment, the water's dissolved oxygen (DO) level increased to 4.8 mg / L, COD to 45 mg / L, ammonia nitrogen to 1.3 mg / L, and the organic matter content in the bottom sediment to 14.5 g / kg. The water quality met the Class IV standard of GB 3838-2002, the black and odorous water phenomenon was completely eliminated, and a stable "plant-benthic organism-microorganism" symbiotic system was formed, resulting in a significant improvement in the ecological environment.

[0048] Comparative experiment: Small, enclosed lakes with the same pollution level as in Example 2 were selected and divided into two groups. One group used the method of this invention (experimental group), and the other group used the traditional method of "physical dredging + chemical oxygenation + single bacterial agent administration" (control group). After 60 days of treatment, the water quality and sediment indicators of the two groups were tested, and the results are shown in Table 1. Table 1. Water quality and sediment test indicators for the experimental and control groups.

[0049] Comparative experiments show that the treatment effect of the method of the present invention is significantly better than that of traditional methods. It has made great improvements in terms of increasing dissolved oxygen in water, removing pollutants, and dissolving bottom sediment, and there is no secondary pollution. The water quality is more stable after treatment.

[0050] This method overcomes the limitations of existing technologies that treat sediment and water in stages, and constructs a simultaneous treatment system of "sediment micro-disturbance - in-situ digestion - water stratified purification - ecological stabilization". It achieves the synergistic effect of sediment pollutant digestion and overlying water purification, solving the problems of asynchronous treatment of the two and re-polluting of water bodies by sediment pollutants in existing technologies. At the same time, it uses a combination of local compound microbial agents and slow-release compound digestive agents, which is different from the use of single microbial agents or single oxidants in the past, and improves the targeting and effectiveness of the treatment.

[0051] This method is simple to operate and has a clear process. All materials are common and environmentally friendly. The local compound bacterial agent is highly adaptable and has a fast colonization rate. The slow-release compound digester and compound flocculant are easy to add. No large and complex equipment is required. The dosage and treatment parameters can be adjusted according to the degree of pollution of the black and odorous water body (mild, moderate, and severe). It is suitable for different types of black and odorous water bodies such as urban rivers, ditches, and small enclosed lakes. The overall treatment cost is low, the effect is good, and the treatment cycle is short (30-45 days for mild black and odorous water bodies, 60-75 days for moderate black and odorous water bodies, and 90-120 days for severe black and odorous water bodies). After treatment, the DO of the water body is stable above 4 mg / L, the heavy metal fixation rate is ≥90%, and the water quality can stably meet the Class IV standard or above of the "Surface Water Environmental Quality Standard" (GB 3838-2002). It has extremely strong engineering application value.

[0052] This method uses environmentally friendly materials throughout the process, producing no toxic or harmful byproducts. The selection of native microbial agents and aquatic plants avoids the invasion of alien species. The introduction of benthic organisms constructs a complete micro-ecological chain, achieving the simultaneous advancement of "pollution control" and "ecological restoration." After treatment, the water transparency increases to 0.8-1.2m, restoring aquatic biodiversity and achieving long-term ecological stability of black and odorous water bodies.

[0053] Therefore, the present invention adopts the above-mentioned method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies. It is applicable to black and odorous water bodies with different pollution levels, such as urban rivers, ditches, and small enclosed lakes. It can achieve simultaneous decomposition of endogenous pollutants in bottom sediment and purification of overlying water bodies, taking into account both short-term odor control and long-term ecological stability.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies, characterized in that, Includes the following steps: Step S1: Water pretreatment and sediment micro-disturbance. Eliminate floating objects and large debris on the water surface. Based on the water depth and sediment topography, finely arrange microfluidic aeration devices for shallow aeration. At the same time, arrange low-frequency micro-disturbance devices according to the sediment texture to micro-disturb the sediment surface layer of 0-15cm. Step S2: In-situ digestion treatment of bottom pollutants. A slow-release composite digestion agent is added to the surface of the bottom sediment using a combination of bottom sediment surface injection and shallow spraying. After addition, the sediment is continuously disturbed by a low-frequency micro-disturbance device. The slow-release composite digestion agent is composed of a slow-release oxidant, a local composite microbial agent, a modified adsorbent, and a slow-release carrier compounded in a certain mass percentage. The preparation, loading process, storage and transportation requirements of each component are clearly defined. Step S3: Layered purification treatment of the overlying water body. While the pollutants in the bottom sediment are being dissolved in step S2, a composite flocculant is added to the middle layer of the water body and stirred and flocculated. An anti-interference ecological floating bed is laid on the surface of the water body and a biofilm carrier is suspended. Step S4: Ecological stabilization and long-term maintenance. Add benthic organisms to the water body according to the established timing, ratio and method. Add diluted local compound bacterial agent in stages. Regularly test water quality and sediment indicators and adjust treatment parameters. Design parameters and coping principles for extreme conditions such as rainfall / flood season, high temperature / low temperature, and high salinity / high turbidity.

2. The method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies according to claim 1, characterized in that, In step S1, the microfluidic aeration device uses microporous aeration heads with a pore size of 50~100μm, arranged in a matrix with a spacing of 0.5~1.0m, and the water disturbance amplitude during aeration is ≤5cm. The aeration intensity of the microfluidic aeration device is dynamically adjusted according to the following formula: ； The aeration intensity is 0.8~1.2m. 3 / (m 2 •h), the aeration time is 2~3h; the aeration heads are arranged at the following heights according to the water depth H: when H<1m, they are arranged at 0.3~0.5m underwater; when H≥1m, they are arranged in layers at 0.5m and 0.8m underwater. The spacing between aeration heads in the bottom mud shallows and silt pits is set at 0.5m, and mobile aeration units are added in the aeration dead corners. The low-frequency micro-disturbance device is an underwater low-frequency vibrator, positioned 10-15 cm above the surface of the bottom sediment; the optimal disturbance frequency of the low-frequency disturbance device is calculated using the following formula: ； The disturbance frequency is 10~15Hz, the disturbance time is 30~45min, and the micro-disturbance range is 0~15cm of the bottom sediment surface; in, This refers to the real-time aeration intensity; The baseline aeration intensity; Dissolved oxygen in stage S1 Target value, ; Real-time dissolved oxygen in water bodies; This is the disturbance correction factor. The values ​​are based on the following criteria: 0.8~0.9 for silt, 1.0~1.1 for a mixture of mud and sand, and 1.1~1.2 for sandy sediment; when the air temperature is ≥30℃. Increase by 0.1, decrease by 0.1 when the temperature is ≤10℃; The optimal perturbation frequency; The measured concentration of organic matter on the surface of the sediment. The baseline value for slightly polluted and odorous organic matter is [value missing]. ; This represents the depth of sediment disturbance.

3. The method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies according to claim 2, characterized in that, In step S2, the dosage of the sustained-release composite digestive agent is calculated according to the following formula: ； in, This refers to the dosage of the digester; This refers to the concentration of sulfides in the sediment. The total concentration of heavy metals in the sediment; This is the pollution correction factor. The values ​​are based on the following criteria: 0.9~1.0 for mildly polluted water bodies, 1.0~1.2 for moderately polluted water bodies, and 1.2~1.3 for severely polluted water bodies. The dosage of the sustained-release compound digester is 200~500g / m³. 2 The mass percentages of each component are as follows: slow-release oxidant 30%~45%, local compound microbial agent 25%~35%, modified adsorbent 20%~30%, and slow-release carrier 5%~10%. The micro-disturbance frequency after addition is 5~8Hz, the duration is 1~2h, and the micro-disturbance is applied to the surface layer of sediment 0~15cm.

4. The method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies according to claim 3, characterized in that, The slow-release oxidant is a compound of calcium peroxide and ozone slow-release microspheres in a mass ratio of 3:1 to 2:1; the ozone slow-release microspheres use hydrophobically modified porous starch as a carrier. The sustained-release carrier is a compound of sodium carboxymethyl cellulose and bentonite, with a ratio of sodium carboxymethyl cellulose to bentonite of 2:1 to 3:1 and a disintegration time of 24 to 48 hours.

5. The method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies according to claim 3, characterized in that, The local compound bacterial agent is composed of Bacillus, photosynthetic bacteria and denitrifying bacteria in a mass ratio of 2:1:1, with an effective live bacteria count ≥60 billion / gram. The local compound bacterial agent is selected from the local environment of the black and odorous water body to be treated. Under high temperature conditions, a high temperature protectant is added, and under low temperature conditions, it is replaced with a low temperature resistant local compound bacterial agent. Under high salinity conditions, the proportion of Bacillus is increased to 3:1:

1.

6. The method for simultaneous decomposition of sediment pollutants and water purification in black and odorous water bodies according to claim 3, characterized in that, The modified adsorbent is an alkali-activated mineral powder modified adsorbent, made from industrial mineral powder and fly ash through alkali activation treatment, used to adsorb heavy metal ions and small molecule organic matter in sediment; the slow-release carrier is a compound of sodium carboxymethyl cellulose and bentonite, with a sodium carboxymethyl cellulose: bentonite ratio of 2:1 to 3:1 and a disintegration time of 24 to 48 hours, used to delay the release rate of the effective components in the composite digester.

7. The method for simultaneous decomposition of sediment pollutants and water purification in black and odorous water bodies according to claim 1, characterized in that, In step S3, the composite flocculant is composed of polyaluminum chloride (PAC), polyacrylamide (PAM), and modified zeolite in a mass ratio of 5:1:3, and the dosage is 50-100 mg / L. After addition, an underwater push-flow agitator is used for engineering stirring. First, the agitator is rapidly stirred at a speed of 150-200 r / min for 10-15 min, and then slowly stirred at a speed of 80-100 r / min for 30-40 min. Step S2 and Step S3 are started simultaneously, with a duration of 48~72h.

8. The method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies according to claim 1, characterized in that, In step S3, the coverage rate of the ecological floating bed is 15%~25%. The ecological floating bed adopts a modular splicing structure, with a counterweight added to the bottom and a net to prevent debris from getting tangled around it. At least one native aquatic plant among calamus, reed, and foxtail grass is planted on the floating bed. The biofilm carrier is specifically a polyurethane sponge carrier or a coconut shell carbon fiber carrier, with a specific surface area ≥1500m². 2 / m 3 Biofilm formation rate ≥ 20 g / m 2 The biofilm carrier undergoes surface cleaning of suspended matter every 3 months.

9. A method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies according to claim 1, characterized in that, In step S4, the benthic organisms are native snails and clams, and the feeding amount is 50~100 ind / m³. 2 Before addition, disinfect by soaking in a 0.5% potassium permanganate solution for 10-15 minutes; the timing of addition is 7 days after flocculation and sedimentation and when the water turbidity is <50 NTU. The ratio of snails to mussels is 3:1, and the addition is done in batches: 50% is added for the first time, and the remaining 50% is added 7 days later. The diluted local compound microbial agent was diluted at a ratio of 1:1000 and was added in stages: once a week for the first two weeks, and once every two weeks for the next two to four weeks. The water body's dissolved oxygen (DO), carbon dioxide (COD), ammonia nitrogen, total phosphorus, and sediment organic matter content are tested every two weeks.

10. A method for simultaneous decomposition of pollutants in bottom sediment and water purification in black and odorous water bodies according to claim 1, characterized in that, In step S4, the principles for dealing with extreme working conditions are as follows: Rainfall / Flood Season: Add 20%~30% flocculant 1~2 days before rainfall, and increase the aeration intensity to 1.2~1.5m. 3 / (m 2 •h); After the flood season, remove floating debris and test the concentration of pollutants in the bottom sediment. If the concentration exceeds the standard, add 10% to 20% slow-release compound digester. High temperature: Add a high temperature protectant to the local compound microbial agent, reduce the dosage by 10%, and change the aeration mode to intermittent mode; Low temperature: Replace with low temperature resistant local bacterial agent, increase oxidant dosage by 20%, and extend sediment micro-disturbance time to 2-3 hours; High salt: Screen salt-tolerant native bacterial agents and increase the proportion of Bacillus spores; add zeolite powder to the modified adsorbent. High turbidity: Add a pretreatment flocculation step to reduce turbidity before proceeding with conventional purification treatment.

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