Water hydroxyl integrated sewage treatment device and sewage treatment method

Abstract

The application discloses a water-hydroxyl integrated sewage treatment device and a sewage treatment method, and the device comprises a flocculation tank, a purification reaction tank, a clean water tank and a slag outlet, a water inlet and a medicine inlet are arranged on one side of the flocculation tank, and a stirrer is further arranged on the upper portion of the flocculation tank; the purification reaction tank comprises an aeration pipe, a hydroxyl generator arranged on the wall of the purification reaction tank and a slag grabber; a slag outlet communicated with the slag outlet is arranged on one side of the slag grabber; a clean water tank is further arranged on the side close to the slag tank of the clean water tank, and a water outlet for discharging clean water is arranged on the clean water tank; the stirring rod of the stirrer extends into the flocculation tank; the purification reaction tank comprises an upper large-diameter tank, a lower small-diameter tank and a transition section arranged between the upper large-diameter tank and the lower small-diameter tank. The hydroxyl radicals generated by splitting water molecules can oxidize and degrade pollutants, at the same time, the micro-gas energy generated by the side reaction can take the suspended particles in the effluent to the water surface and remove the suspended particles through the slag grabber, and the micro-gas energy also has the sterilization and disinfection effect.

Description

Technical Field

[0001] This invention belongs to the field of water treatment, and specifically relates to an integrated water and hydroxyl wastewater treatment device and wastewater treatment method. Background Technology

[0002] Due to the dispersed population, complex terrain, and limited economic conditions in rural areas of my country, it is difficult to transport domestic sewage from individual households or small-scale joint households, as well as wastewater from small-scale livestock farming, to centralized sewage treatment plants through the construction of large-scale pipeline networks. Treating sewage through decentralized sewage treatment technologies or integrated equipment reduces the cost of laying pipeline networks and is more suitable for rural areas without centralized treatment facilities.

[0003] Commonly used decentralized wastewater treatment technologies in rural areas include mainstream processes such as membrane bioreactors (MBR), stabilization ponds / purification ponds, biofilters, and MBBR. These traditional treatment technologies have certain treatment efficiencies, but they also have limitations.

[0004] Stabilization ponds utilize natural or artificially excavated water bodies to treat wastewater naturally, resulting in low treatment costs. Stabilization ponds require a large area and are more suitable for regions with ample land, but they are greatly affected by climate conditions, and algal blooms can lead to increased COD in the effluent.

[0005] Membrane bioreactors (MBRs) integrate membrane separation and biological treatment technologies, resulting in high-quality effluent, high ammonia nitrogen removal rates, small footprint, and low sludge production. However, membrane fouling control is costly, difficult, and complex, and membrane module maintenance is also challenging.

[0006] Biological filters utilize biofilm technology for wastewater treatment. Their reaction devices are simple and easy to control, and the purification effect is stable. However, they are prone to attracting mosquitoes and flies, have a long construction period, and high construction costs.

[0007] Traditional treatment technologies face significant obstacles to large-scale promotion in rural areas due to various constraints such as large land area requirements, high construction and operation costs, and low efficiency in treating wastewater with low carbon-to-nitrogen ratios.

[0008] Existing integrated rural wastewater treatment equipment, in terms of structure and function, resembles a miniature version of the aforementioned commonly used technologies combined in various ways. The integrated rural wastewater treatment equipment produced by environmental protection manufacturers on the market primarily utilizes the biofilm method, which involves cultivating active microorganisms that attach to biomass packing material, degrading pollutants in wastewater through biological processes. This method offers advantages such as low sludge production and minimal secondary pollution.

[0009] The current technical problems are: The processing capacity is generally 10 t / d to 200 t / d. Equipment with a smaller processing capacity will face many problems such as large fluctuations in influent and instability of the biological system. Rural domestic sewage typically consists mainly of wastewater from washing, kitchens, and toilets. While the organic matter concentration is low, nitrogen and phosphorus levels are relatively high, resulting in an influent C / N ratio often below 3:1 (ideal denitrification requires a C / N ratio ≥ 4–6). This low carbon source limits the denitrification process, leading to low biological nitrogen removal efficiency and making it difficult for effluent quality indicators (especially TN and TP) to meet national discharge standards. Farmers working away from home for extended periods will experience a significant decrease in the activity of microorganisms in the existing decentralized treatment system, requiring specialized technicians and a lengthy training process to restart. Aquaculture only generates large amounts of wastewater during the tailwater discharge period. Taking shrimp farming in small sheds as an example, there is basically no or very little wastewater discharge during the 2-3 month farming period. However, during the tailwater discharge period, all wastewater needs to be treated within 20 days. If shrimp are farmed twice a year, the existing decentralized biological treatment system is difficult to adapt to the cycle of low water levels followed by massive loads, then low water levels again, and then massive loads again, resulting in substandard effluent water quality.

[0010] Electrolytic flotation technology is well-suited for decentralized treatment of rural domestic sewage and livestock wastewater. However, this technology also has operational challenges. Hardness ions (Ca²⁺, Mg²⁺) in the water tend to precipitate at the cathode, and heavy metals or organic matter may cover the electrode surface, affecting efficiency. Frequent maintenance or replacement of the electrode plates further hinders the widespread adoption of this technology in decentralized rural sewage treatment. Summary of the Invention

[0011] This invention provides an integrated water-hydroxyl wastewater treatment device and wastewater treatment method to solve the technical problems in the current wastewater treatment process, such as poor oxidation, decolorization, and sterilization capabilities, substandard effluent quality, low mass transfer efficiency of existing electrolytic flotation water treatment plates installed at the bottom of the reaction tank, easy clogging, easy passivation of the plates, troublesome disassembly and assembly, high maintenance requirements, and difficulty in promotion.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: an integrated water-hydroxyl wastewater treatment device includes a flocculation tank, a purification reaction tank, a clear water tank and a slag discharge tank, wherein a water inlet and a chemical inlet are provided on one side of the flocculation tank, and a stirrer is also provided on the upper part of the flocculation tank. The purification reaction tank includes an aeration pipe, a hydroxyl generator installed on the tank wall, and a slag remover; a slag outlet connected to a slag discharge trough is provided on one side of the slag remover; a clear water tank is also provided on the side of the clear water tank near the slag trough, and a water outlet for discharging clean water is provided on the clear water tank; the stirring rod of the agitator extends into the flocculation tank. The purification reaction tank includes an upper large-diameter tank, a lower small-diameter tank, and a transition section between the upper large-diameter tank and the lower small-diameter tank.

[0013] Furthermore, the aeration pipes are installed in the lower small-diameter pool or in the middle of the pool.

[0014] Furthermore, the distance between the aeration pipe and the bottom of the purification reaction tank is 150 – 300 mm.

[0015] Furthermore, the vertical distance from the center line of the aeration pipe to the bottom surface of the electrode plate is 150-350 mm.

[0016] Furthermore, the electrode area of ​​the hydroxyl generator is 100 cm². 2 -240cm 2 The hydroxyl generator density is set at 2-6 units per square meter.

[0017] Furthermore, the angle of the inclined plane of the reaction tank: cone angle 30°-60°.

[0018] Furthermore, the anode plate of the hydroxyl generator is made of titanium or titanium alloy as the substrate, and the outer surface of the substrate is coated with a composite material coating; the cathode of the hydroxyl generator is made of stainless steel.

[0019] Furthermore, the composite material coating is prepared by coating with a composite material solution, drying, and sintering. The composite material solution is a nano-solution formed by dissolving transition metal elements in ethanol. The nano-solution uses transition metal particles as solutes. The transition metal elements are iridium, platinum, cerium, yttrium, tantalum, cobalt, and titanium. The molar ratio of the transition metal elements iridium, platinum, cerium, yttrium, tantalum, cobalt, and titanium in the composite material solution is 15-20:8-10:5-15:13-19:9-17:16-23:30-50.

[0020] Furthermore, the hydroxyl generator is horizontally mounted on the wall of the lower small-diameter pool.

[0021] The purification method using the above-mentioned purification device includes the following steps: Step 1, wastewater enters the flocculation tank through the inlet, and at the same time, the chemical inlet begins to feed the chemical, and the agitator works to make the chemical and raw water fully mixed. Step 2: The wastewater, which is mixed evenly with the reagent, overflows into the purification reaction tank. At this time, the generator at the bottom of the reaction tank starts to work and produces hydroxyl radicals to oxidize and degrade water pollutants. At the same time, the side reaction produces nano-sized microbubbles. As the bubbles rise, they collide with and adhere to colloids, suspended solids, oil droplets or algae in the water, forming "gas-solid / liquid" flocs that float to the water surface. Step 3: The flocculent scum is scraped into the scum trough by the scum removal machine and then discharged. Step four: After purification, the clean water passes through the clean water tank and is discharged through the outlet; Step 5: The equipment aerates the water through the aeration pipe at the bottom of the small-diameter pool for 5-15 minutes every 20-60 minutes. Step 6: Every 10-45 consecutive days of equipment operation, regularly fill the bottom small-diameter pool with reagents such as citric acid to soak and maintain the electrode plates. The design of the bottom small-diameter pool reduces the amount of reagent used.

[0022] The beneficial effects of this invention are reflected in: 1. A water-hydroxyl integrated wastewater treatment device and method, which can degrade pollutants by oxidizing the hydroxyl radicals generated by the cleavage of water molecules, while the micro-gas generated by the side reaction can carry suspended particles in the wastewater to the water surface for removal by a sludge scraper, producing a 1+1 greater than 2 effect, and also has a sterilization and disinfection effect. All three effects are achieved in the same reaction zone. Compared with existing biochemical technologies, the device is greatly simplified, saving space and eliminating the need for complex equipment such as air compressors and dissolved air tanks. The system has a high degree of integration and is suitable for small or decentralized treatment scenarios.

[0023] 2. Short hydraulic residence time (10-60 minutes), and extremely small footprint (approximately 10%-30% of current technology); 3. Unaffected by environmental factors such as temperature, the effluent water quality remains stable; 4. Non-biological wastewater treatment, can be operated by simply plugging in electricity, can be turned on and off at will, does not require long-term debugging, and is suitable for scenarios with intermittent sewage discharge (such as aquaculture wastewater); 5. It can treat small-volume wastewater, and can even be used to treat domestic or livestock wastewater from individual farmers.

[0024] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention; the main objects and other advantages of the invention may be realized and obtained by means of the embodiments particularly pointed out in the description. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention.

[0026] Figure 2 This is a side view of Embodiment 2 of the present invention.

[0027] Figure 3 This is a top view of the aeration pipe.

[0028] Figure 4 This is a side view of the purification device.

[0029] Figure 5 This is a 3D view of the purification device.

[0030] Figure 6 This is a side view of Embodiment 3 of the present invention.

[0031] Attached diagram labels: 1-Inlet, 2-Drug inlet, 3-Flocculation tank, 4-Agitator, 5-Slag remover, 6-Reaction tank, 7-Slag trough, 8-Clear water tank, 9-Outlet, 10-Generator, 11-Aeration pipe, 12-Transition section. Detailed Implementation

[0032] The technical solutions of the present invention will be described in detail below through embodiments. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solutions of the present invention, and should not be construed as limiting the technical solutions of the present invention.

[0033] See Figure 1 , 3 As shown in Figures 4 and 5, the purification device includes a flocculation tank 3, a purification reaction tank 6, a clear water tank 8, and a slag discharge trough 7. The flocculation tank 3 has a water inlet 1 and a chemical inlet 2 on one side, and a stirrer 4 is installed at the top of the flocculation tank 3. The purification reaction tank 6 includes an upper large-diameter tank, a lower small-diameter tank, and a transition section 12 between the upper large-diameter tank and the lower small-diameter tank. The angle of the inclined surface of the reaction tank 6 is a cone angle of 30°-60°.

[0034] The purification reaction tank 6 includes an aeration pipe 11, a hydroxyl generator 10 installed on the tank wall of the purification reaction tank 6, and a slag remover 5; a slag outlet connected to a slag discharge trough 7 is provided on one side of the slag remover 5; a clear water tank 8 is also provided on the side of the clear water tank 8 near the slag trough 7, and a water outlet 9 for discharging clean water is provided on the clear water tank 8.

[0035] In this process, the stirring rod of the agitator 4 extends into the flocculation tank 3.

[0036] The aeration pipe 11 can be installed at the bottom of the pool or in the middle of the pool.

[0037] The distance between aeration pipe 11 and the bottom of purification reaction tank 6 is 150 – 300 mm.

[0038] The vertical distance from the center line of aeration pipe 11 to the bottom surface of the electrode plate is 150-350 mm. This effectively disturbs the boundary layer and prevents bubble short circuits. If the distance is too close, the disturbance is insufficient, and if the distance is too far, the disturbance is attenuated.

[0039] The area of ​​the hydroxyl generator's 10 electrode plates, calculated using the anode plate area, is 100 cm². 2 -240cm 2 The hydroxyl generator 10 is set at a density of 2-6 per square meter.

[0040] The purification reaction tank 6 uses an electrochemical method to pyrolyze water to generate a large amount of ·OH, a strong oxidizing substance, and microbubbles. ·OH has a redox potential of 2.8 volts and has extremely strong oxidizing ability. It can react rapidly with organic pollutants to convert them into carbon dioxide and water. At the same time, the side reaction generates nano-sized microbubbles that can carry away suspended particles in the wastewater.

[0041] The anode plate of the hydroxyl generator 10 can be made of titanium or titanium alloy as the substrate, and the outer surface of the substrate is coated with a composite material coating. This composite material coating is prepared by coating with a composite material solution, drying, and sintering. The composite material solution is a nano-solution formed by dissolving transition metal elements in ethanol, with transition metal particles as the solute. The transition metal elements are iridium, platinum, cerium, yttrium, tantalum, cobalt, and titanium. The molar ratio of the transition metal elements iridium, platinum, cerium, yttrium, tantalum, cobalt, and titanium in the composite material solution is 15-20:8-10:5-15:13-19:9-17:16-23:30-50. The electrode coating is not easily peeled off, resulting in a long electrode lifespan.

[0042] The cathode of the hydroxyl generator 10 is made of stainless steel.

[0043] Pressure vessel materials include stainless steel, fiberglass, PP, PE, carbon steel lined with plastic, carbon steel lined with fluoropolymer, and electrostatic powder coating.

[0044] The generator 10 electrode assembly is installed on the side wall of the lower small-diameter pool (see attached). Figure 2 The side-mounted electrode assembly of generator 10 allows for a more uniform flow field as water passes between the electrodes, reducing dead zones. Vertical arrangement facilitates top-down or lateral flow patterns, increasing the contact frequency between wastewater and electrode surfaces, enhancing mass transfer, and improving reaction efficiency. Laterally fixed electrode mounting prevents sludge or suspended solids accumulation; gravity helps particles settle naturally to the bottom of the tank rather than adhering to the electrode surface. Side-mounted electrodes are generally easier to disassemble, inspect, and clean, especially suitable for electrochemical systems requiring regular maintenance. The modular electrode structure facilitates individual electrode replacement, reducing downtime. The bottom groove and rational side arrangement contribute to a more uniform electric field distribution, reducing localized high or low current densities, thereby improving overall electrochemical reaction efficiency and extending electrode life. The bottom groove design reduces the consumption of cleaning agents for periodic electrode cleaning, lowering operating costs and reducing secondary pollution. Side mounting also facilitates automatic control and wiring management, improving system stability. Aeration pipes 11 are located below the bottom electrode assembly in the groove (see Appendix). Figure 3 It can aerate regularly to prevent scale buildup on the electrode plates.

[0045] How to use this device: Added agents: a) Inorganic flocculants: PAC (polyaluminum chloride), PAFC (polyaluminum ferric chloride), PFS (polyferric sulfate), polyaluminum sulfate (PAS) polysilicate, polyaluminum silicate sulfate (PASS), polyaluminum silicate chloride (PASC), and silicon-iron composite inorganic polymeric flocculants, etc.; b) Organic polymeric flocculants: PAM (cationic, anionic, and nonionic polyacrylamide, etc.); c) Microbial flocculants, etc.

[0046] The inlet water temperature of the purification device is 5-45℃, the current density is 5-30mA / cm2, the electrode spacing is 1-100mm, and it operates continuously.

[0047] Raw water enters the flocculation tank 3 through inlet 1, while chemicals are simultaneously introduced through inlet 2. Agitator 4 operates to thoroughly mix the chemicals with the raw water. The water then overflows into the purification reaction tank 6. At this point, generator 10 at the bottom of reaction tank 6 generates hydroxyl radicals that oxidize and degrade water pollutants. Simultaneously, a side reaction produces nanoscale microbubbles. As these bubbles rise, they collide with and adhere to colloids, suspended solids, oil droplets, or algae in the water, forming gas-solid / liquid flocs that float to the surface. These flocs are then scraped onto the sludge trough 7 by sludge remover 5 and discharged. The purified water then passes through the clear water tank 8 and is discharged through outlet 9. The integrated purification equipment periodically aerates the water to prevent scale buildup on the plates and periodically soaks the plates with reagents such as citric acid for maintenance. The recessed design at the bottom reduces the amount of reagent used.

[0048] Example 2: See Figure 2 The wastewater to be treated was effluent from a septic tank in a residential community in Beijing. It was pumped into the integrated unit at a flow rate of 2 L / min using a metering pump. The raw water first entered the flocculation zone, where polyaluminum chloride (PAC) was added at a rate of 4 ml / min using a peristaltic pump. After thorough mixing, the wastewater overflowed into the reaction zone, which has a volume of 120 L and a hydraulic retention time of 1 hour. Due to the high amount of suspended solids in the wastewater, the lower slope of reaction tank 6 was inclined at a 45° angle. Pollutants were oxidized and degraded by the ·OH generated by the core components, and suspended solids were carried to the surface by microbubbles and scraped off. The influent and effluent water quality are shown in the table below. raw water Out of water SS (mg / L) 183 6 Color intensity (mg / L) 1251 1 COD (mg / L) 300 4.7 NH3-N (mg / L) 145 1.33 Total nitrogen (mg / L) 167.1 1.74 Total P (mg / L) 4.55 0.39 Fecal coliform count (CFU / L) 760 Not detected Example 2 showed that the effluent consistently met the Class A standard of the "Discharge Standard of Pollutants for Urban Wastewater Treatment Plants" for 3 months.

[0049] Example 3: See Figure 6 In the treatment of shrimp tail water in a county in Beihai City, Guangxi, the raw water is pumped into an integrated device at a flow rate of 12L / min by a metering pump. The raw water first enters the flocculation zone, where polyaluminum chloride (PAC) is added at a flow rate of 12ml / min using a metering pump. After thorough mixing, the wastewater overflows into the 120L reaction zone and undergoes a hydraulic retention of 10 minutes. The wastewater contains relatively few suspended solids. The lower slope of reaction tank 6 has an inclination angle of 30°. Pollutants are oxidized and degraded by ·OH generated by the core component, and suspended solids are carried to the liquid surface by microbubbles and scraped off. The influent and effluent water quality are shown in the table below. Serial Number Indicator Name raw water Water quality after HPT treatment 1 <![CDATA[Chemical Oxygen Demand (COD Mn )(mg / L)]]> 25.4 4.8 2 Total nitrogen (mg / L) 5.82 1.06 3 Ammonia nitrogen (mg / L) 3.56 0.06 4 Total phosphorus (mg / L) 2.1 0.49 5 Suspended solids (SS) (mg / L) 107 Not detected 6 Fecal coliform count (MPN / L) <![CDATA[9×10 3 ]]> Not detected Example 3: The effluent quality fully met the Class I standard of Guangxi's "Seawater Aquaculture Wastewater Discharge Standard" DB45 / T2841-2024 for 6 months.

[0050] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An integrated water and hydroxyl wastewater treatment device, characterized in that: It includes a flocculation tank (3), a purification reaction tank (6), a clear water tank (8) and a slag discharge tank (7). The flocculation tank (3) is provided with a water inlet (1) and a chemical inlet (2) on one side, and a stirrer (4) is also provided on the upper part of the flocculation tank (3). The purification reaction tank (6) includes an aeration pipe (11), a hydroxyl generator (10) installed on the wall of the purification reaction tank (6), and a slag remover (5); a slag outlet connected to the slag outlet trough (7) is provided on one side of the slag remover (5); a clear water tank (8) is also provided on the side of the clear water tank (8) near the slag outlet trough (7), and a water outlet (9) for discharging clean water is provided on the clear water tank (8); the stirring rod of the agitator (4) extends into the flocculation tank (3); The purification reaction tank (6) includes an upper large-diameter tank, a lower small-diameter tank, and a transition section (12) set between the upper large-diameter tank and the lower small-diameter tank.

2. The apparatus as described in claim 1, characterized in that: The aeration pipe (11) is installed in the lower small-diameter pool or in the middle of the pool.

3. The apparatus as claimed in claim 1, characterized in that: The distance between the aeration pipe (11) and the bottom of the purification reaction tank (6) is 150 – 300 mm.

4. The apparatus as claimed in claim 1, characterized in that: The vertical distance from the center line of the aeration pipe (11) to the bottom surface of the electrode plate is 150-350 mm.

5. The apparatus as claimed in claim 1, characterized in that: The electrode area of ​​the hydroxyl generator (10) is 100 cm². 2 -240cm 2 The hydroxyl generator (10) is set at a density of 2-6 per square meter.

6. The apparatus as claimed in claim 1, characterized in that: The angle of the inclined plane of the reaction tank (6) is 30°-60°.

7. The apparatus as claimed in claim 1, characterized in that: The anode plate of the hydroxyl generator (10) is made of titanium or titanium alloy as the substrate, and the outer surface of the substrate is coated with a composite material coating; the cathode of the hydroxyl generator (10) is made of stainless steel cathode.

8. The apparatus as claimed in claim 7, characterized in that: The composite material coating is prepared by coating with a composite material solution, drying, and sintering. The composite material solution is a nano-solution formed by dissolving transition metal elements in ethanol. The nano-solution uses transition metal particles as solutes. The transition metal elements are iridium, platinum, cerium, yttrium, tantalum, cobalt, and titanium. The molar ratio of the transition metal elements iridium, platinum, cerium, yttrium, tantalum, cobalt, and titanium in the composite material solution is 15-20:8-10:5-15:13-19:9-17:16-23:30-50.

9. The apparatus as claimed in claim 1, characterized in that: The hydroxyl generator (10) is horizontally installed on the wall of the lower small-diameter pool.

10. A wastewater treatment method using the apparatus according to any one of claims 1-9, characterized in that: The steps include the following: Step 1, wastewater enters the flocculation tank (3) through the inlet (1), and at the same time, the chemical inlet (2) starts to feed the chemical, and the agitator (4) works to make the chemical and raw water fully mixed; Step 2: The wastewater mixed with the reagent overflows into the purification reaction tank (6). At this time, the hydroxyl radicals generated by the generator (10) at the bottom of the reaction tank (6) oxidize and degrade water pollutants. At the same time, the side reaction generates nano-scale microbubbles. During the rise of the bubbles, they collide with and adhere to colloids, suspended solids, oil droplets or algae in the water, forming "gas-solid / liquid" flocs that float to the water surface. Step 3: The flocculent scum is scraped into the scum trough (7) by the scum remover (5) and then discharged. Step 4: After purification, the clean water passes through the clean water tank (8) and is discharged through the outlet (9); Step 5: The equipment aerates the water through the aeration pipe (11) at the bottom of the small-diameter pool for 5-15 minutes every 20-60 minutes. Step 6: Every 10-45 consecutive days of equipment operation, regularly fill the bottom small-diameter pool with reagents such as citric acid to soak and maintain the electrode plates. The design of the bottom small-diameter pool reduces the amount of reagent used.

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