Mine water grading synergistic oil and turbidity removal system and method

Abstract

The invention discloses a grading collaborative oil and turbidity removal system and method for mine water, and belongs to the technical field of mine water treatment. According to the invention, a grading synergistic oil removal and turbidity removal process is adopted, and a trace amount of oil is removed while suspended matters are removed, so that the oil content of the effluent of the mine water reaches a relatively high standard, and meanwhile, the investment and land occupation of mine water treatment facilities are reduced; by adopting the biodegradation effect of the oleophylic filler, the filtering period is prolonged, the backwashing frequency and the medicament consumption are reduced, meanwhile, high surface load is adopted in the oil-water separation area to quickly remove oil, and a turbulent flow plate is arranged in the filtering area, so that the oil skimming efficiency is improved, the filter material loss is prevented, the service life of the filter material is prolonged, and the operation cost of the system is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine water treatment, and in particular relates to a system and method for coordinated classification and oil removal and turbidity removal of mine water. Background Art

[0002] Mine water is one of the main wastewaters generated during coal mining. Its core pollutants are high concentrations of suspended solids, primarily composed of clay and coal dust, typically ranging from 300 to 3,000 mg / L. Due to geological conditions and underground mechanical operations, some mine water also contains trace amounts of oil pollutants, generally ≤5 mg / L, including oil leakage from mechanical emulsification. In the past, because oil content fell below the Coal Industry Pollutant Emission Standard, mine water deoiling technology received little attention.

[0003] In recent years, as the country has strengthened its requirements for mine water resource reuse, effluent standards have been significantly raised: petroleum contaminants must be ≤1 mg / L, and in some scenarios, even meet the Class III water limit of 0.05 mg / L in the "Surface Water Environmental Quality Standards." Furthermore, oil contaminants can easily clog membrane systems used in deep mine water treatment, further highlighting the need for oil removal.

[0004] At present, the conventional removal of suspended solids generally adopts the coagulation sedimentation filtration process, and the removal of oil adopts oil separation, flotation or demulsification and re-flotation process, which needs to be implemented in steps. In order to remove PPM-level oil, additional processes need to be added, the process is lengthy, and investment and land costs are increased. Conventional dissolved air flotation, cavitation flotation and other processes are not efficient in removing emulsified oil, and it is difficult to stably reach the ultra-low limit of 0.05 mg / L. Additional activated carbon adsorption or special oil removal filters are required, which increases operating costs.

[0005] In view of this, this application is hereby filed. Summary of the Invention

[0006] The purpose of the present invention is to provide a system and method for the graded and coordinated oil and turbidity removal of mine water. By adopting a graded and coordinated oil and turbidity removal process, trace amounts of oil can be removed while removing suspended matter, and the oil content of the mine water outlet can be made to reach a higher standard. At the same time, the investment and land occupation of mine water treatment facilities can be reduced, thereby effectively solving the above-mentioned problems.

[0007] Technical solution: A mine water graded and coordinated oil and turbidity removal system includes a regulating tank and a lifting pump. Mine water enters the coagulation reaction tank, flocculation reaction zone, oil-water separation zone, sedimentation zone, post-mixing zone, micro-nano bubble generation zone and filtration zone from the regulating tank through the lifting pump, wherein:

[0008] The coagulation reaction tank, flocculation reaction zone and post-mixing zone are respectively provided with a mixing stirrer, a flocculation stirrer and a post-mixing stirrer;

[0009] The upper portion of the oil-water separation zone is provided with a first oil skimming device and a first oil collecting device;

[0010] The sedimentation area is provided with a scraper and an inclined plate, and a mud discharge pipe is connected to the bottom;

[0011] A micro-nano bubble generator is installed in the micro-nano bubble generating area;

[0012] A second oil skimming device and a second oil collecting device are provided at the upper part of the filtration area, and a filter material layer is provided at the lower part. The upper part of the filter material layer is filled with oleophilic lightweight porous biological filler with a thickness of 500-700 mm and a particle size of 2-5 mm, and the lower part is filled with quartz sand with a thickness of 700-1100 mm and a particle size of 0.6-1.2 mm. A supporting layer with a thickness of 100-200 mm is provided at the bottom of the filter material layer, and a water distribution system is connected below the supporting layer.

[0013] In a further embodiment, the light porous biofiller has a density of 1.2-1.8 g / cm³.

[0014] The above technical solutions can help improve buoyancy matching, oil adsorption rate and microbial carrier stability, while achieving further adsorption and biodegradation of residual oil, extending the filtration cycle and thus reducing operating costs.

[0015] In a further embodiment, a water distribution device is provided at the connection point between the micro-nano bubble generating area and the filtering area.

[0016] The above technical solution ensures uniform flow distribution and avoids excessive local loads that lead to flow interruption or filter layer blockage.

[0017] In a further embodiment, a turbulence plate is provided on one side of the filtration zone between the second oil skimming device and the filter material layer.

[0018] The above technical solution helps to break up the interface layer, disperse the oil droplets, make the floating oil easier to concentrate, and improve the oil skimming efficiency; at the same time, it prevents the oil droplets from penetrating the filter layer due to laminar flow and not floating up, thus ensuring the working stability of the filter layer.

[0019] In a further embodiment, a regulating valve is installed on the drain pipe.

[0020] Through the above technical solution, the water outlet speed can be adjusted according to the operating load or water quality changes, which helps to maintain the stability of the liquid level in the filtration area and avoid disturbing the filter layer structure.

[0021] A method for synergistically removing oil and turbidity from mine water by classification includes the following steps:

[0022] Step 1: Coagulation and flocculation pretreatment: Add coagulant and flocculant to the coagulation reaction tank and flocculation reaction zone respectively, and turn on the mixing mixer and flocculation mixer to react under the stirring condition of 8-12 times circulation multiple, so that the oil and suspended matter are fully in contact and adhere to each other, forming large particles that are easy to sink;

[0023] Step 2: Primary Sedimentation, Oil Removal and Turbidity Removal: The mixed liquor passes through the upward section and enters the oil-water separation zone equipped with a pre-sedimentation function. A surface load of 20-50 m³ / (m²·h) is used to cause heavy suspended matter to settle and suspended oil to float. The first oil skimmer and first oil collector installed in this zone perform preliminary oil removal. After the initial oil removal, the mixed liquor enters the sedimentation zone, where heavy suspended matter sinks.

[0024] Step 3: Post-mixing demulsification and micro-nano flotation: The liquid after precipitation flows into the post-mixing zone, a special demulsifier is added into the post-mixing zone, and the post-mixing mixer is turned on. The mixed liquid after stirring enters the micro-nano bubble generating zone and fully reacts with bubbles with a diameter of 1 μm. The bubbles absorb the demulsified oil droplets, causing the oil droplets to aggregate and float;

[0025] Step 4: Downward flow filtration: The oily water enters the downward flow filtration area, and the flotation area is set above the filtration area with a load of 4~8m 3 / (m 2 h), the floating oil is removed by the second oil skimmer and the second oil collector, and the sewage is filtered from top to bottom through the filter layer, and the load at the filter layer is 6~10m 3 / (m 2 h);

[0026] Step 5. Multi-stage filter media and coordinated biological oil removal: The upper part of the filter media layer in the filtration area is oleophilic, lightweight, porous biological filler, which is used to adsorb and biodegrade residual oils, and the lower part is quartz sand, which is used to further filter suspended matter to ensure that the effluent meets the standards.

[0027] In a further embodiment, the micro-nano bubble reaction in step 3 is completed before water is distributed to the filtration zone, and the filtration zone maintains a stable liquid level through a regulating valve to prevent floating oil from entering the filter material layer.

[0028] The above technical solution is helpful to improve the floating rate of oil droplets, and at the same time can effectively prevent the oil droplets from entering the filter layer with the water flow after demulsification, causing blockage or excessive biological load.

[0029] In a further embodiment, the heavy suspended matter in the sedimentation zone of step 2 sinks and accumulates on the bottom and side walls of the sedimentation zone, is scraped off by a scraper and an inclined plate, and is discharged through a mud discharge pipe.

[0030] Through the above technical solution, the automatic collection and discharge of sludge can be achieved, avoiding accumulation causing a decrease in sedimentation efficiency or system blockage, and extending the equipment operation cycle.

[0031] In a further embodiment, the area ratio of the oil-water separation zone to the sedimentation zone in step 2 is 1:3-1:5, and the surface load of the oil-water separation zone is 2-3 times that of the sedimentation zone.

[0032] The above technical solution helps to improve the sedimentation efficiency, and takes into account the rapid removal of floating oil in oil-water separation and the sedimentation of particles in the sedimentation area, effectively avoiding system shortcomings.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) Through hierarchical collaborative design, the oil-water separation zone and the sedimentation zone are linked, and micro-nano flotation and filtration are coupled, integrating the oil removal and turbidity removal processes into an integrated system, replacing the traditional lengthy step-by-step process and significantly reducing investment and land occupation;

[0035] (2) By setting up a micro-nano bubble generation zone before filtration and combining it with a special demulsifier, the demulsified oil droplets are efficiently adsorbed and polymerized, thereby improving the removal rate of emulsified oil. At the same time, the filter layer uses oleophilic lightweight porous biological fillers and quartz sand, and physical and biological deep oil removal is achieved. The oil content can be stably reduced to below 0.05 mg / L, and the suspended solids can be reduced to below 5 mg / L.

[0036] (3) By using the biodegradation effect of oleophilic fillers, the filtration cycle is extended, the backwash frequency and reagent consumption are reduced, and at the same time, high surface load rapid oil removal is adopted in the oil-water separation area and turbulent plates are set in the filtration area to prevent filter media loss and increase the service life of the filter media. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of the mine water classification and coordinated oil and turbidity removal system of the present invention;

[0038] Figure 2 This is a schematic diagram of the structure of the mine water classification and coordinated oil and turbidity removal system of the present invention;

[0039] Figure 3 This is a schematic diagram of the operations of steps 1 and 2 in the method for coordinated oil and turbidity removal by classification of mine water according to the present invention;

[0040] Figure 4 This is a schematic diagram of the operations of steps 3 to 5 in the method for stratified and coordinated oil and turbidity removal of mine water in the present invention.

[0041] Figure numerals: 1. regulating tank; 2. lifting pump; 3. coagulation reaction tank; 301 mixing mixer; 4. flocculation reaction zone; 401. flocculation mixer; 5. oil-water separation zone; 501. first oil skimming device; 502. first oil collecting device; 6. sedimentation zone; 601. scraper; 602 inclined plate; 7. post-mixing zone; 701. post-mixing mixer; 8. micro-nano bubble generating zone; 801. micro-nano bubble generator; 9. filtration zone; 901. water distribution device; 902. second oil skimming device; 903. second oil collecting device; 904. regulating valve; 905. quartz sand; 906. lightweight porous biological filler; 907. turbulence plate. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] like Figure 1 and Figure 2 As shown, the present application provides a mine water graded coordinated oil removal and turbidity removal system, including a regulating tank 1 and a lifting pump 2, the mine water enters the coagulation reaction tank 3, the flocculation reaction zone 301 mixing mixer through the lifting pump 2 from the regulating tank 1 in sequence; 4, the oil-water separation zone 5, the sedimentation zone 6, the post-mixing zone 602 inclined plate; 7, the micro-nano bubble generating zone 8 and the filtration zone 9, wherein the coagulation reaction tank 3, the flocculation reaction zone 301 mixing mixer; 4 and the post-mixing zone 602 inclined plate; 7 are respectively provided with a mixing mixer, a flocculation mixer 401 and a post-mixing mixer 701; the upper part of the oil-water separation zone 5 is provided with a first oil skimming device 501 and a first oil collecting device 502; a scraper 601 and an inclined plate are provided in the sedimentation area 6, and a mud discharge pipe is connected to the bottom; a micro-nano bubble generating area 8 is installed with a micro-nano bubble generator 801; a second oil skimming device 902 and a second oil collecting device 903 are provided on the upper part of the filtration area 9, and a filter material layer is provided on the lower part. The upper part of the filter material layer is filled with a 500-700 mm thick, oleophilic, lightweight porous biological filler 906 with a particle size of 2-5 mm, and the lower part is filled with quartz sand 905 with a thickness of 700-1100 mm and a particle size of 0.6-1.2 mm. A supporting layer with a thickness of 100-200 mm is provided at the bottom of the filter material layer, and a drainage pipe is connected below the supporting layer.

[0044] Furthermore, a water distribution device 901 is provided at the connection point between the micro-nano bubble generating area 8 and the filtering area 9 to evenly distribute the flow and avoid interruption of flow or clogging of the filter layer due to excessive local load.

[0045] Furthermore, the filter area 9 is provided with a turbulence plate 907 on one side between the second skimming device 902 and the filter material layer, which is used to break the interface layer and disperse the oil droplets, making it easier to concentrate the floating oil and improving the skimming efficiency; at the same time, it prevents the oil droplets from penetrating the filter layer due to the laminar flow not floating up, thereby ensuring the working stability of the filter material layer.

[0046] Furthermore, a regulating valve 904 is installed on the drain pipe to control the liquid level of the filter area 9 when filtering water, ensuring that floating pollutants are removed in time without causing the floating pollutants to enter the filter material layer.

[0047] Example 1: Application of mine water treatment scale 1000m³ / h

[0048] The design capacity of a coal mine's mine water is 1000m³ / h. The raw water suspended solids (SS) concentration is 600~3000mg / L, and the oil pollutant concentration is 1~5mg / L. The treated effluent must meet the high standards of SS ≤ 10mg / L and oil ≤ 0.05mg / L.

[0049] The mine water classification and coordinated oil and turbidity removal system provided by the present invention has a system structure as follows: Figure 1 and Figure 2 As shown, the method see Figure 3 and Figure 4 , the specific steps are as follows:

[0050] The first step, coagulation and flocculation reaction stage:

[0051] The mine water first enters the coagulation reaction tank 3 and fully reacts with the added coagulant through the mixing mixer;

[0052] Then it enters the flocculation reaction zone 301 mixing mixer; 4, slowly stirred by the flocculation mixer 401, under the condition of 8 to 12 times circulation multiples, the oil and suspended matter are promoted to adhere to form flocs.

[0053] Step 2: Primary precipitation and oil-water separation stage:

[0054] The mixed liquid after stirring enters the oil-water separation zone 5 through the upward turning section. This zone is a pre-settling area. The upper part of the zone is equipped with a first oil skimmer 501 and a first oil collector 502 to recover the floating oil.

[0055] The liquid enters the sedimentation zone 6, where inclined plates and scrapers 601 are installed to achieve efficient sedimentation of large particles and heavy suspended solids, and the sludge is discharged from the bottom through the sludge discharge pipe.

[0056] Step 3: Post-mixing demulsification and micro-nano bubble reaction zone:

[0057] The settled liquid enters the post-mixing zone 602, where a special demulsifier is added and stirred by the post-mixing mixer 701;

[0058] After entering the micro-nano bubble generating area 8, a large number of 1 μm bubbles are formed under the action of the micro-nano bubble generator 801, and react with the demulsified oil droplets to form polymerized oil droplets that float and rise.

[0059] The fourth step is a filtering and biologically synergistic oil removal stage.

[0060] After being uniformly distributed by the water distribution device 901, the water enters the filtering area 9, which is provided with a second oil skimming device 902 and a second oil collecting device 903 at the upper part for removing the floating oil.

[0061] The filter material layer is divided into three sections.

[0062] The upper layer is an oil-wet lightweight porous biological filler 906 with a thickness of 500-700 mm and a particle size of 2-5 mm, and the apparent density is 1.2-1.8 g / cm³.

[0063] The middle layer is quartz sand 905 with a thickness of 700-100 mm and a particle size of 0.6-1.2 mm.

[0064] The bottom layer is a supporting layer with a thickness of 100-200 mm.

[0065] The filtering liquid flows from top to bottom, and after adsorption and biodegradation in the oil-wet biological filler, it is further de-turbidized by the quartz sand 905 layer and then discharged.

[0066] The filtering area 9 is provided with a turbulent plate 907 to destroy the oil-water interface and improve the oil skimming efficiency, and a regulating valve 904 is arranged to stabilize the liquid level and prevent the floating oil from penetrating the filter material layer.

[0067] Through the above process, the final effluent has a stable petroleum concentration of less than 0.05 mg / L and an SS of less than 5 mg / L, meeting the national reuse standards.

[0068] In addition, the use of the system can cancel the traditional dissolved air flotation tank and oil removal filter, and compared with the original system, the investment is reduced by about 38%, the land occupation is saved by about 20%, the operation energy consumption is reduced by 0.2 yuan / m³, and the economic benefits are significant.

[0069] Example Two: Application of a mine water treatment scale of 2000 m³ / h

[0070] The design scale of the raw water of a certain coal mine is 2000 m³ / h, the SS is 150-1000 mg / L, and the oil is 0.2-1 mg / L, and the treatment method is the same as that of Example One.

[0071] After using the system of the application:

[0072] The activated carbon adsorption unit is cancelled, and the potential fire and explosion prevention requirements are reduced;

[0073] The problem of delayed transportation of activated carbon and the potential safety hazard in operation are avoided.

[0074] The system can save activated carbon dosing cost of about 0.4 yuan / m³ per ton of water;

[0075] At the same time, the amount of sludge caused by activated carbon is reduced by about 60 tons per day, reducing the cost of sludge disposal.

[0076] This system operates stably and meets emission standards, while simplifying operation and management and adapting to the coal mine environment.

[0077] Through the above embodiments, the present invention has the following obvious advantages:

[0078] (1) Synergistic oil removal mechanism:

[0079] Primary sedimentation stage: high circulation flocculation enhances the adsorption of oil by clay / coal powder;

[0080] Micro-nano flotation section: 1μm-level bubbles efficiently adsorb demulsified oil droplets, with a floating removal rate of >90%;

[0081] Biological filtration section: The oleophilic filler absorbs the residual oil and biodegrades it to avoid physical blockage.

[0082] (2) Anti-clogging design:

[0083] Oil-water separation zone 5 pre-settles large suspended solids and protects the inclined plate;

[0084] Turbulator plates 907 prevent oil droplets from penetrating the filter layer;

[0085] The regulating valve 904 stabilizes the liquid level to ensure that the floating oil is removed in time.

[0086] (3) Economic breakthrough:

[0087] Replace dissolved air flotation, activated carbon and other units, reducing investment by 15~38%;

[0088] Biodegradation reduces backwash frequency and chemical consumption, and operating costs drop by 0.2~0.4 yuan / m³.

[0089] In this application, the surface load of the oil-water separation zone is 20~50m³ / (m²·h), and the load of the flotation zone set above the filtration zone is 4~8m 3 / (m 2 ·h), the load at the filter layer is 6~10m 3 / (m 2 ·h).

[0090] In order to further improve the sedimentation efficiency and take into account the rapid removal of floating oil in oil-water separation and the particle sedimentation in the sedimentation zone, the area ratio of the oil-water separation zone to the sedimentation zone is 1:3~1:5, and the surface load of the oil-water separation zone is 2~3 times that of the sedimentation zone.

[0091] The above is a detailed description of the present application in conjunction with specific embodiments, and cannot be deemed to limit the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or replacements can be made, and all should be deemed to fall within the scope of protection of the present application.

Claims

1. A mine water classification and coordinated oil and turbidity removal system, comprising a regulating tank and a lift pump, characterized in that: Mine water enters the coagulation reaction tank, flocculation reaction zone, oil-water separation zone, sedimentation zone, post-mixing zone, micro-nano bubble generation zone and filtration zone from the regulating tank through the lifting pump, among which: The coagulation reaction tank, flocculation reaction zone and post-mixing zone are respectively provided with a mixing stirrer, a flocculation stirrer and a post-mixing stirrer; The upper portion of the oil-water separation zone is provided with a first oil skimming device and a first oil collecting device; The sedimentation area is provided with a scraper and an inclined plate, and a mud discharge pipe is connected to the bottom; A micro-nano bubble generator is installed in the micro-nano bubble generating area; A second oil skimming device and a second oil collecting device are provided at the upper part of the filtration area, and a filter material layer is provided at the lower part. The upper part of the filter material layer is filled with oleophilic lightweight porous biological filler with a thickness of 500-700 mm and a particle size of 2-5 mm, and the lower part is filled with quartz sand with a thickness of 700-1100 mm and a particle size of 0.6-1.2 mm. A supporting layer with a thickness of 100-200 mm is provided at the bottom of the filter material layer, and a water distribution system is connected below the supporting layer.

2. The mine water classification and coordinated oil and turbidity removal system according to claim 1 is characterized by: The lightweight porous biofiller has a density of 1.2 to 1.8 g / cm³.

3. The mine water classification and coordinated oil and turbidity removal system according to claim 1 is characterized by: A water distribution device is provided at the connection point between the micro-nano bubble generating area and the filtering area.

4. The mine water classification and coordinated oil and turbidity removal system according to claim 1 is characterized by: The filter zone is provided with a turbulence plate on one side between the second oil skimming device and the filter material layer.

5. The mine water classification and coordinated oil and turbidity removal system according to claim 1 is characterized by: A regulating valve is installed on the drain pipe.

6. The method for synergistically removing oil and turbidity from mine water by classification according to any one of claims 1 to 5, characterized in that it comprises the following steps: S1. Coagulation and flocculation pretreatment: Add coagulant and flocculant to the coagulation reaction tank and flocculation reaction zone respectively, and turn on the mixing mixer and flocculation mixer. React under the stirring condition of 8-12 times of circulation multiples to make the oil and suspended matter fully contact and adhere to each other, forming large particles that are easy to sink; S2. Primary sedimentation, oil removal, and turbidity removal: The mixed liquid passes through the upward section and enters the oil-water separation zone equipped with a pre-settling function. A surface load of 20-50 m³ / (m²·h) is used to cause heavy suspended matter to settle and suspended oil to float. The first oil skimmer and first oil collector installed in this zone perform preliminary oil removal. After the initial oil removal, the mixed liquid enters the sedimentation zone, where heavy suspended matter sinks. S3, post-mixing demulsification and micro-nano flotation: The liquid after precipitation flows into the post-mixing zone, where a special demulsifier is added and the post-mixing mixer is turned on. The mixed liquid after stirring enters the micro-nano bubble generation zone and fully reacts with bubbles with a diameter of 1 μm. The bubbles absorb the demulsified oil droplets, causing the oil droplets to aggregate and float; S4, Downward flow filtration: The oily water enters the downward flow filtration area, and the flotation area is set above the filtration area with a load of 4~8m 3 / (m 2 h), the floating oil is removed by the second oil skimmer and the second oil collector, and the sewage is filtered from top to bottom through the filter layer, and the load at the filter layer is 6~10m 3 / (m 2 h); S5. Multi-stage filter media and coordinated biological oil removal: The upper part of the filter media layer in the filtration area is oleophilic, lightweight, porous biological filler, which is used to adsorb and biodegrade residual oils, and the lower part is quartz sand, which is used to further filter suspended matter to ensure that the effluent meets the standards.

7. The method for synergistically removing oil and turbidity from mine water by classification according to claim 6, characterized in that: The micro-nano bubble reaction in step 3 is completed before water is distributed to the filtration area. The filtration area maintains a stable liquid level through a regulating valve to prevent floating oil from entering the filter material layer.

8. The method for synergistically removing oil and turbidity from mine water by classification according to claim 6, characterized in that: In step 2, the heavy suspended matter in the sedimentation zone sinks and accumulates at the bottom and side walls of the sedimentation zone, is scraped off by the scraper and inclined plate, and is discharged through the mud discharge pipe.

9. The method for synergistically removing oil and turbidity from mine water by classification according to claim 6, characterized in that: The area ratio of the oil-water separation zone to the sedimentation zone in step 2 is 1:3~1:5, and the surface load of the oil-water separation zone is 2~3 times that of the sedimentation zone.

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