A ship sewage treatment system applying photocatalyst

Abstract

The present invention provides a ship sewage treatment system applying a photocatalyst, mainly relating to the field of ship sewage treatment. A ship sewage treatment system applying a photocatalyst includes a pre-screening box, a flocculation box, a filtration box and an ultraviolet photocatalysis box which are sequentially connected by pipelines. A rotating drum screen covering the water inlet is rotatably arranged in the pre-screening box. A plurality of folding plates are staggeredly arranged in the flocculation box. A plurality of photocatalytic nets are arranged in an array in the ultraviolet photocatalysis box. The top of the photocatalytic net is hinged to the top of the ultraviolet photocatalysis box, and hinged non-Newtonian fluid dampers are respectively arranged between the photocatalytic nets on both sides and the two ends of the ultraviolet photocatalysis box. The beneficial effects of the present invention are as follows: The present invention incorporates a new technology for treating sewage with a photocatalyst, uses the rolling of the ship as power, enables the sewage to fully contact the photocatalyst for treatment, has stronger adaptability, higher treatment capacity, is more energy-saving, and can meet the requirements of ship sewage treatment.

Description

Technical Field

[0001] The present invention mainly relates to the field of ship sewage treatment, and specifically, it is a ship sewage treatment system applying photocatalysts. Background Art

[0002] Currently, the sewage treatment devices used on ships mainly adopt traditional processes of filtration, flocculation, and biological treatment. Since a ship will continuously vibrate and sway while sailing on the ocean, and the treatment of sewage by microorganisms usually requires a relatively calm environment and a relatively suitable temperature, this results in the fact that biological treatment usually cannot achieve an ideal effect. Especially when undertaking scientific research tasks in high-latitude regions, biological treatment requires consuming a large amount of energy to maintain the temperature for the microorganisms to work, causing waste of energy and the treatment effect is hardly satisfactory. Summary of the Invention

[0003] To solve the deficiencies of the prior art, the present invention provides a ship sewage treatment system applying photocatalysts. It incorporates the new technology of treating sewage with photocatalysts, and at the same time uses the rolling of the ship as power to enable the sewage to fully contact the photocatalysts for treatment. It has stronger adaptability, higher treatment capacity, and is more energy-efficient, and can meet the requirements of ship sewage treatment.

[0004] To achieve the above object, the present invention is realized through the following technical solutions:

[0005] A ship sewage treatment system applying photocatalysts includes a pre-screening tank, a flocculation tank, a filtration tank, and an ultraviolet photocatalysis tank that are sequentially connected by pipelines. The pre-screening tank filters out solid debris in the sewage. The flocculation tank causes the suspended particles in the sewage to aggregate and become larger, or form flocs, thereby accelerating the sedimentation of particles. The filtration tank is used to filter out flocculation impurities and reduce the turbidity of the sewage. The ultraviolet photocatalysis tank decomposes the dissolved organic matter and the particulate organic matter that is difficult to degrade in the sewage through photocatalysts, and at the same time plays a role in sterilization, enabling the sewage to meet the discharge standards.

[0006] A rotating drum screen covering the water inlet of the pre-screening tank is rotatably arranged inside the pre-screening tank. At least one fin plate is arranged on the outer side of the rotating drum screen. The fin plate can cooperate with the rolling of the ship to drive the rotating drum screen to swing, so that the debris inside the rotating drum screen will not block the mesh holes. A number of folding plates are staggeredly arranged inside the flocculation tank. The folding plates also cooperate with the rolling of the ship to cause the sewage to oscillate back and forth in the channels between the folding plates, playing a stirring effect. A dosing machine connected to the flocculation tank is arranged on one side of the flocculation tank. At least three layers of filter media with different particle sizes are arranged in the filtration tank from top to bottom. The particle size of the filter media decreases from the upper layer to the lower layer. Partition filter plates are arranged at the top of the topmost filter media, at the bottom of the bottommost filter media, and between each layer of filter media.

[0007] A number of photocatalytic meshes are arranged in an array inside the ultraviolet photocatalytic box. The top of each photocatalytic mesh is hinged to the top of the ultraviolet photocatalytic box. A connecting rod is hinged to each side of each photocatalytic mesh. As the ship rolls, the sewage impacts the photocatalytic mesh, causing the photocatalytic mesh to swing back and forth with the water flow, playing a stirring role and making the photocatalytic effect better. Non-Newtonian fluid dampers are respectively arranged at the hinges between the photocatalytic meshes on both sides and the two ends of the ultraviolet photocatalytic box. The non-Newtonian fluid dampers hardly work when the ship rolls slightly, ensuring the stirring effect under calm sailing conditions. The greater the ship roll, the stronger the damping effect of the non-Newtonian fluid, thereby restricting the swing amplitude of the photocatalytic mesh and balancing the stirring effect inside the ultraviolet photocatalytic box under different sea states. At the same time, it protects the photocatalytic mesh when the ship rolls greatly, avoiding damage due to large swing amplitude and frequency of the photocatalytic mesh. At least one ultraviolet light source is arranged on each photocatalytic mesh. The axis of the rotary drum screen is arranged along the length direction of the ship. The folding plates are arranged in an array along the length direction of the ship. The photocatalytic meshes are arranged in an array along the width direction of the ship.

[0008] Preferably, the base material of the photocatalytic mesh is a light metal mesh, and the light metal mesh has a titanium dioxide or modified titanium dioxide coating. A mesh frame is arranged outside the photocatalytic mesh, and at least one support beam is arranged in the middle of the photocatalytic mesh. The ultraviolet light source is installed on the support beam. The settings of the mesh frame and the support beam reinforce the photocatalytic mesh. At the same time, the base material of the photocatalytic mesh is a light metal mesh, which also improves its strength, enabling the photocatalytic mesh to maintain a good working state.

[0009] Preferably, the downstream of the ultraviolet photocatalytic box is connected to an ultrafilter and a reverse osmosis filter in sequence through a pipeline. The ultrafilter and the reverse osmosis filter can deeply filter the sewage after photocatalytic treatment, thereby obtaining a water source that can be used or drunk for emergencies.

[0010] Preferably, one or more of a security filter, a dosing device, and a pH adjustment device are arranged upstream of the ultrafilter and the reverse osmosis filter. The above equipment is used for pre-protection of the membrane system to ensure the service life of the membrane system.

[0011] Preferably, a reflux pipe is arranged between the ultraviolet photocatalytic box and the flocculation box, and a diversion pipe is arranged between the pre-screening box and the ultraviolet photocatalytic box.

[0012] Preferably, a sewage tank is arranged upstream of the pre-screening box, and a seawater inlet pipe is arranged on the sewage tank or the pre-screening box.

[0013] Preferably, the rotary drum screen includes a cylindrical tubular screen. A number of reinforcing ribs are evenly arranged on the outer wall of the tubular screen. Reinforcing rings are provided at both ends of the tubular screen. Multiple reinforcing ribs are all connected between the reinforcing rings. Both ends of the rotary drum screen are rotatably connected to the inner wall of the pre-screening box. The rotary drum screen has a reinforcing structure, which can ensure the strength of the rotary drum screen.

[0014] Preferably, the flocculation box includes a mixing area and a reaction area. The folding plates are arranged in the reaction area. The folding plates are wavy plates or angled plates. The spacing between the folding plates shows a change from wide to narrow. Through the channels with the change from wide to narrow, the sewage can be fully oscillated therein, achieving a better mixing effect and improving both the flocculation efficiency and the flocculation effect.

[0015] Preferably, at least one stirring paddle wheel is arranged in the mixing area. The rotating shaft of the stirring paddle wheel is perpendicular to the liquid inlet direction after the sewage enters the flocculation box.

[0016] Preferably, a gravel layer with a diameter of 2 - 8 mm, a quartz sand layer with a diameter of 1.0 - 1.5 mm, a quartz sand layer with a diameter of 0.5 - 1.0 mm or a bituminous coal layer filter material are sequentially arranged from top to bottom in the filtration box.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] In the sewage treatment link of the ship, the present invention adds a photocatalyst to degrade the dissolved organic matter in the sewage. At the same time, it can effectively kill bacteria and viruses in the sewage, enabling the water quality to meet the discharge standard. By replacing biological treatment with photocatalytic sewage treatment, the photocatalytic sewage treatment method has stronger adaptability and will not be affected by the shaking of the ship during ocean navigation. At the same time, the photocatalytic sewage treatment has a wider applicable temperature range and can also work in high-latitude regions, effectively solving the problem of sewage discharge during ship navigation.

[0019] The photocatalytic unit of the present invention uses a photocatalytic net instead of a photocatalytic plate or tube structure. Although the efficiency is lower than that of the latter, it is not easily blocked and can be treated statically in a modular manner without complicated maintenance, which is more suitable for the ship's use environment.

[0020] Each sewage treatment unit of the present invention is modular and separately treated. After the sewage treatment is completed under this module, it is transferred to the next process for treatment, which is more suitable for the discontinuous sewage generation environment on the ship.

[0021] The present invention makes full use of the rolling of the ship as power to fully stir the sewage in the flocculation box and the ultraviolet photocatalytic box. The entire treatment process does not require external power, saving energy consumption.

[0022] The swing of the photocatalytic mesh inside the ultraviolet photocatalytic box of the present invention is driven by the rolling of the ship, and at the same time, the swing amplitude is limited by the non-Newtonian fluid damper, so that when the ship rolls greatly, the swing amplitude of the photocatalytic mesh can be suppressed, and the sewage stirring rate inside the ultraviolet photocatalytic box can still maintain a relatively stable state when the ship's rolling changes greatly, which is more convenient for monitoring the sewage treatment state inside the ultraviolet photocatalytic box. At the same time, the non-Newtonian fluid damper restricts the swing of the photocatalytic mesh, and can protect the photocatalytic mesh when the ship rolls greatly, avoiding damage to the photocatalytic mesh. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention;

[0024] FIG. Figure 2 is a schematic structural diagram of Embodiment 2 of the present invention;

[0025] FIG. Figure 3 is a schematic structural diagram of Embodiment 3 of the present invention;

[0026] FIG. Figure 4 is a schematic structural diagram of the pre-screening box of the present invention;

[0027] FIG. Figure 5 is a schematic diagram of the internal structure of the flocculation box of the present invention in a top view state;

[0028] FIG. Figure 6 is a schematic diagram of the partial sectional structure of the flocculation box of the present invention in a left view state;

[0029] FIG. Figure 7 is a schematic diagram of the sectional structure of the filtration box of the present invention;

[0030] FIG. Figure 8 is a schematic diagram of the internal structure of the ultraviolet photocatalytic box of the present invention;

[0031] FIG. Figure 9 is a schematic diagram of the structure of the photocatalytic mesh of the present invention;

[0032] FIG. Figure 10 is a schematic diagram of the structure of a single photocatalytic mesh monomer of the present invention.

[0033] Reference numerals shown in the drawings: 1, pre-screening box; 2, flocculation box; 3, filtration box; 4, ultraviolet photocatalytic box; 5, ultrafilter; 7, reverse osmosis filter; 8, sewage tank; 11, rotary drum screen; 12, fin plate; 13, seawater inlet pipe; 21, chemical feeder; 22, folding plate; 23, stirring paddle wheel; 31, partition filter plate; 41, photocatalytic mesh; 42, non-Newtonian fluid damper; 43, ultraviolet light source; 44, connecting rod; 45, diversion pipe; 46, reflux pipe; 411, mesh frame; 412, support beam; 61, security filter; 62, chemical addition device; 63, pH adjustment device; 64, buffer tank. Detailed implementation manners

[0034] In combination with the accompanying drawings and specific embodiments, the present invention will be further described. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by this application. Embodiment 1

[0035] This embodiment provides a ship sewage treatment system applying a photocatalyst, which is used to treat domestic sewage and experimental wastewater generated by ships to meet the discharge standards and avoid polluting the ocean.

[0036] This device includes a pre-screening tank 1, a flocculation tank 2, a filtration tank 3, and an ultraviolet photocatalytic tank 4 that are sequentially connected by pipelines. The pre-screening tank 1 serves as a temporary storage place for sewage. After the ship's water is used, it is collected into the pre-screening tank 1 through a complex pipeline. The pre-screening tank 1 performs the first filtration on the sewage, filters out the solid insoluble impurities therein, and cleans them during subsequent shutdown maintenance. Specifically, in this embodiment, the filter screen of the pre-screening tank 1 adopts a rotary drum screen 11 covering its water inlet. The rotary drum screen 11 itself is rotatably installed on the inner wall of the pre-screening tank 1. The outer side wall of the rotary drum screen 11 is the filtering part, and solid impurities can be intercepted inside the screen. Specifically, in order to prevent the bottom of the screen from being blocked by impurities over time and affecting the filtering effect, the rotary drum screen 11 in this embodiment can swing with the impact of the water flow, thereby achieving a certain backwashing effect and slowing down the trend of the screen holes being blocked.

[0037] Specifically, the rotary drum screen 11 includes a cylindrical barrel net. A plurality of reinforcing ribs are uniformly arranged on the outer wall of the barrel net. The reinforcing ribs reinforce the barrel net, improve its overall strength, and prevent deformation and damage due to the accumulation of solid pollutants and the erosion of water flow. Reinforcing rings are arranged at both ends of the barrel net, and a plurality of reinforcing ribs are connected between the reinforcing rings. The reinforcing rings also play a role in reinforcing the barrel net. At the same time, the reinforcing rings also serve as the part for rotary installation and are rotatably connected to the inner wall of the pre-screening tank 1. More specifically, if the length span of the rotary drum screen 11 is relatively large, several reinforcing rings can be selectively added in the middle of the rotary drum screen 11 to further optimize the strength of the rotary drum screen 11.

[0038] Furthermore, in this embodiment, both ends of the rotary drum screen 11 are rotatably connected to the inner wall of the pre-screening tank 1 through plain bearings, thereby improving the rotational stability of the rotary drum screen 11, ensuring the installation firmness of the rotary drum screen 11, and guaranteeing the filtering effect on the impurities in the sewage.

[0039] At least one fin plate 12 is arranged on the outer side of the rotary drum screen 11. In this embodiment, the fin plate 12 is installed on the reinforcing rib. The axis of the rotary drum screen 11 is arranged along the length direction of the ship. The rolling of the ship will cause the sewage in the front-stage screening box 1 to oscillate, thereby flushing the fin plate 12, providing power for the swing of the rotary drum screen 11, avoiding the blockage of the sieve holes of the rotary drum screen 11 by sundries, and improving the operation duration of this front-stage screening device.

[0040] The water outlet of the front-stage screening box 1 is connected to the water inlet of the flocculation box 2 through a pipeline, and a water pump is connected in series on the connecting pipeline as power to introduce the sewage in the front-stage screening box 1 into the flocculation box 2. The flocculation box 2 includes a mixing area and a reaction area. At least one stirring paddle wheel 23 is arranged in the mixing area, and the stirring paddle wheel 23 is driven by a motor. The rotating shaft of the stirring paddle wheel 23 is perpendicular to the liquid inlet direction after the water inlet of the flocculation box 2.

[0041] A chemical dosing machine 21 connected to the flocculation box 2 is arranged on one side of the flocculation box 2. The chemical dosing machine 21 is provided with a chemical dosing pump, and the chemical dosing pump adds the flocculation agent into the flocculation box 2 through a hose. Specifically, the flocculation agent is added synchronously when the sewage is introduced into the flocculation box 2, so that the sewage can be fully mixed with the flocculation agent. The water inlet of the flocculation box 2 is located above the stirring paddle wheel 23, and the chemical dosing port of the flocculation box 2 is located on one side of the water inlet. When the sewage is injected, the chemical dosing port injects the flocculation agent synchronously, and the two start to mix while being injected. Subsequently, the mixed liquid passes through the stirring paddle wheel 23, and the stirring paddle wheel 23 rotates at a high speed to further stir the mixed liquid, so that the flocculant and the sewage are mixed more fully to improve the flocculation effect of suspended solids and colloidal substances in the sewage.

[0042] The baffle plates 22 are arranged in the reaction area. The baffle plates 22 are arranged in an array along the length direction of the ship, and channels extending along the width direction of the ship are formed between adjacent baffle plates 22. The baffle plates 22 are wavy plates or angled plates, and the distance between the baffle plates 22 presents a change in width. Through the rolling of the ship, the sewage in the reaction area reciprocally disturbs in the channels between the baffle plates 22. Through the change in width between the baffle plates 22, the sewage can be more fully mixed in the reaction area. The rolling of the ship serves as power, causing the disturbance of the sewage to form a stirring effect, accelerating the flocculation of suspended solids and colloidal substances, improving the flocculation effect, and shortening the flocculation time.

[0043] The flocculation tank 2 is connected to the filtration tank 3 through a pipeline, and a pump body is connected in series on the pipeline. The sewage in the flocculation tank 2 can be introduced into the filtration tank 3 through the pump body. The water inlet of the filtration tank 3 is located at the top, and the water outlet of the filtration tank 3 is located at the bottom. At least three layers of filter media with different particle sizes are arranged in the filtration tank 3 from top to bottom, and the particle size of the filter media decreases from the upper layer to the lower layer. Partition filter plates 31 are arranged at the top of the topmost layer of filter media, at the bottom of the bottommost layer of filter media, and between each layer of filter media. The partition filter plates 31 are provided with filter holes not larger than the adjacent filter media layers in an array. The partition filter plates 31 limit the filter media to prevent the filter media from being mixed and scattered under the roll and pitch of the ship, and ensure the filtration effect under unstable conditions.

[0044] Specifically, the filtration tank 3 is of a cylindrical structure, and annular platforms corresponding to the partition filter plates 31 are arranged in the filtration tank 3. The partition filter plates 31 are detachably installed on the annular platforms by bolts.

[0045] Specifically, in this embodiment, a gravel layer with a thickness of 600 - 1000 mm and a diameter of 2 - 8 mm, a quartz sand layer with a thickness of 400 - 600 mm and a diameter of 1.0 - 1.5 mm, and a quartz sand layer or anthracite coal layer filter media with a thickness of 400 - 600 mm and a diameter of 0.5 - 1.0 mm are arranged in the filtration tank 3 in a progressive manner from top to bottom. The gravel layer filter media at the top layer filters large-diameter flocculent impurities and at the same time plays a role in dispersing the water flow, enabling the sewage to be evenly dispersed to the middle and lower layer filter media. The quartz sand layer filter media in the middle layer continues to filter the next-level flocculent impurities, and the quartz sand or anthracite coal layer filter media in the lower layer filters small-diameter flocculent impurities, so that the flocculent impurities in the sewage are completely filtered, without affecting the subsequent sewage treatment steps.

[0046] Specifically, in order to make the sewage more dispersed in the filtration tank 3 and make the removal of flocculent impurities more uniform, a conical disperser is installed at the top of the filtration tank 3. The diameter of the disperser is about two-thirds of the diameter of the filtration tank 3. The water inlet position of the filtration tank 3 is at the exact center of the top of the disperser. Through the dispersion and buffering effects of the disperser, the sewage can be evenly dispersed onto the filter media, and at the same time, the impact on the filter media is reduced, making the filtration tank 3 have a better effect on removing flocculent impurities.

[0047] The water outlet at the bottom of the filtration tank 3 is connected to the water inlet of the ultraviolet photocatalytic tank 4 through a pipeline, and a pump body is connected in series on the pipeline. There is a certain space at the bottom of the filtration tank 3 as a temporary storage position for the filtered sewage, and the pump body can introduce the filtered sewage into the ultraviolet photocatalytic tank 4.

[0048] A plurality of photocatalytic nets 41 are arranged in an array in the ultraviolet photocatalytic box 4. The top of the photocatalytic net 41 is hinged to the top of the ultraviolet photocatalytic box 4. A connecting rod 44 is hinged on both sides of each photocatalytic net 41. The connecting rods 44 on both sides can make all the photocatalytic nets 41 work in conjunction. At least one ultraviolet light source 43 is arranged on each photocatalytic net 41. The photocatalytic nets 41 are arranged in an array along the width direction of the ship. The rolling of the ship drives the sewage to oscillate back and forth. The oscillation of the sewage impacts the photocatalytic net 41, thereby driving the photocatalytic net 41 to oscillate back and forth, achieving a stirring effect, so that the photocatalyst can fully contact with the sewage, thereby improving the photocatalytic effect.

[0049] The substrate of the photocatalytic mesh 41 is a light metal mesh with a titanium dioxide or modified titanium dioxide coating on the light metal mesh. The photocatalyst absorbs light energy through ultraviolet light. When the photon energy is greater than the bandgap width of the photocatalyst, the valence band electrons of the photocatalyst will be excited to jump to the conduction band, thereby generating holes (h + ), generating electrons in the conduction band (e - The photogenerated electrons and holes have strong redox ability. They will react with oxygen and water molecules in water on the surface of the photocatalyst to generate free radicals with strong oxidizing properties, such as hydroxyl radicals (-OH) and superoxide radicals (-O2 - ). These free radicals are key active species in photocatalytic oxidation reactions. They can react with organic pollutants. The generated hydroxyl radicals and superoxide radicals have strong oxidizing ability and can attack organic pollutants in sewage, degrading them into small molecular organic matter, and finally mineralizing them into carbon dioxide, water and inorganic ions. In addition, hydroxyl radicals and superoxide radicals can destroy the cell membranes of microorganisms such as bacteria and viruses and the biological macromolecules in the cells, making them inactive, thereby achieving the purpose of sterilization and disinfection.

[0050] The photocatalytic net 41 has a mesh frame 411 on the outside, at least one support beam 412 is arranged in the middle of the photocatalytic net 41, and the ultraviolet light source 43 is installed on the support beam 412. The mesh frame 411 and the support beam 412 both play the role of reinforcing the photocatalytic net 41. The ultraviolet light source is installed on the support beam 412. In this embodiment, the support beam 412 is numerically set at the center of the photocatalytic net 41, and the ultraviolet light source is arranged on both sides of the support beam 412. The wiring of the ultraviolet light source is collected at the top and led to the outside at the outlet, wherein the ultraviolet light source adopts a waterproof plastic shell as protection. The ultraviolet light source can excite the titanium dioxide photocatalyst, which has the effect of purifying water quality and sterilizing and disinfecting. At the same time, the ultraviolet light itself also has a bactericidal effect, and can play a better purification role under the dual effect.

[0051] Photocatalytic meshes 41 on both sides and the ultraviolet photocatalytic tank 4 are respectively provided with hinged non-Newtonian fluid dampers 42 at both ends. The non-Newtonian fluid damper 42 can balance the amplitude of the ship's rolling. When the sea surface is relatively calm and the ship's rolling is small, the water flow oscillation generated by the rolling will not cause too much impact on the photocatalytic mesh 41. At this time, the non-Newtonian fluid damper 42 does not act, enabling the photocatalytic mesh 41 to perform small-range reciprocating swings along with the impact of the water flow, playing a role in stirring and mixing, and accelerating the purification treatment of water quality. When there are large winds and waves on the sea surface and the ship's rolling is large, the water flow oscillation generated by the rolling has a greater impact on the photocatalytic mesh 41. At this time, both the swing amplitude and force of the photocatalytic mesh show an increasing trend. After being subjected to an instantaneous overload impact force, the non-Newtonian fluid damper 42 presents a rigid state, which can inhibit the swing amplitude of the photocatalytic mesh 41 and prevent the photocatalytic mesh 41 from being damaged due to large-amplitude and rapid swings. At the same time, the swing amplitude of the photocatalytic mesh 41 is balanced through the limiting effect of the non-Newtonian fluid damper 42, that is, the stirring efficiency of the sewage in the ultraviolet photocatalytic tank 4 is balanced, thereby balancing the treatment rate of the sewage in the ultraviolet photocatalytic tank 4 to a certain extent, so that when the rolling amplitudes of the ship are inconsistent, the treatment time of the sewage is basically the same.

[0052] In this embodiment, the sewage in the ultraviolet photocatalytic tank 4 is regularly sampled and inspected. By regularly sampling and monitoring the concentration changes of pollutants in the sewage, such as indicators like chemical oxygen demand (COD), biochemical oxygen demand (BOD), total organic carbon (TOC), etc., to evaluate the effect of photocatalytic treatment. After waiting for the treatment to meet the standards, the treated sewage is discharged into the ocean through the drain outlet of the ultraviolet photocatalytic tank 4. Embodiment 2

[0053] When the proportion of biochemical sewage used in experiments in the ship sewage is relatively high, there are more refractory organic substances and more dissolved organic matter (DOM) in the sewage. These substances are difficult to remove by flocculation. At the same time, after photocatalytic treatment, these organic substances will still be decomposed into small-molecule organic substances, and may not meet the discharge standards either. Based on this situation, on the basis of Embodiment 1, a reflux pipe 46 is provided between the ultraviolet photocatalytic tank 4 and the flocculation tank 2, and a diversion pipe 45 is provided between the ultraviolet photocatalytic tank 4 and the pre-screening tank 1. Pumps are connected in series on both the reflux pipe 46 and the diversion pipe 45. Specifically, the outlet pipe of the ultraviolet photocatalytic tank 4 and the reflux pipe 46 are connected through a tee, and they can share the same pump body. The end of the reflux pipe 46 is connected to the inlet of the flocculation tank 2 through a tee. Valves are installed on both the reflux pipe 46 and the outlet pipe of the ultraviolet photocatalytic tank 4 to control the flow direction of the sewage. The outlet pipe of the pre-screening tank 1 and the diversion pipe 45 are connected through a tee, and they can share the same pump body. The outlet pipe of the pre-screening tank 1 is connected to the inlet of the flocculation tank 2, and the end of the diversion pipe 45 is connected to the inlet of the ultraviolet photocatalytic tank 4 through a tee. Valves are installed on both the diversion pipe 45 and the outlet pipe of the pre-screening tank 1 to control the flow direction of the sewage.

[0054] The diversion pipe 45 is used to directly introduce sewage into the ultraviolet photocatalytic tank 4 for preliminary photocatalytic treatment, and the reflux pipe 46 is used to reflux the sewage after preliminary photocatalytic treatment into the flocculation tank 2 for flocculation precipitation. After the flocculation precipitation is completed, the sewage enters the ultraviolet photocatalytic tank 4 for secondary photocatalytic treatment and sterilization treatment for the second time, so as to improve the sewage treatment efficiency and sewage treatment effect.

[0055] Furthermore, when the above treatment method is adopted, the turbidity of the sewage should not exceed 300 NTU, otherwise it will seriously affect the treatment effect of the ultraviolet photocatalytic tank 4 and the service life of the photocatalytic mesh 41.

[0056] If the turbidity of the sewage is too high, the sewage can first pass through the flocculation tank 2 for flocculation precipitation and then enter the filter tank 3 for filtration, and then reflux back to the flocculation tank 2 after photocatalytic treatment to repeat the above process, and the experimental biochemical sewage is thoroughly purified through at least two processes of flocculation precipitation - filtration - photocatalysis. Example 3

[0057] When the ship needs to carry out long-term scientific research tasks and cannot be replenished in time by docking at the shore, the sewage treatment system can be used to fully treat the sewage, and the treated sewage can be used for non-drinking purposes or as a drinking water source after deep purification.

[0058] Specifically, based on the sewage treatment system of Example 1, in this example, the ultraviolet photocatalytic tank 4 is connected in sequence to an ultrafilter 5 and a reverse osmosis filter 7 through pipelines downstream. A booster pump is added on the front side of the ultrafilter 5, and the booster pump pumps the sewage after photocatalytic treatment into the ultrafilter 5. Under pressure, the sewage passes through the ultrafiltration membrane, and can filter out suspended particles, colloids, most bacteria and some viruses, etc., thus serving as a pre-treatment process for the reverse osmosis filter 7 to reduce the pressure of the reverse osmosis filter 7. The sewage filtered by the ultrafilter 5 has reached a certain degree of cleanliness and can be used as non-contact water such as toilet flushing and deck washing. A booster pump is also installed on the front side of the reverse osmosis filter 7 to increase the pressure on the reverse osmosis filter 7, so that the water can pass through the reverse osmosis membrane of the reverse osmosis filter 7. The water treated by the reverse osmosis filter 7 can effectively remove impurities such as dissolved solids, inorganic salts, organic matters, bacteria, and viruses in the water, and the desalination rate is generally greater than 98%, and the turbidity is controlled within 0.1 NTU, and it has reached the quality of high-purity water and can be used as drinking water.

[0059] Applying this equipment as an emergency treatment for ship sewage can provide sufficient water sources for the ship when the ship is engaged in long-term scientific research work and cannot be replenished by docking at the shore. When the ship is docked for repair, the membrane system needs to be backwashed and cleaned to maintain its stable operation.

[0060] More specifically, one or more of a security filter 61, a chemical dosing device 62, and a pH adjustment device 63 can be installed upstream of the ultrafilter 5 and selected according to the state of the ship sewage. The security filter 61 (precision filter), as the last insurance process before the membrane treatment system, can filter the particulate matter generated in the photocatalysis process or the microbial impurities that have not been effectively removed, reducing the pressure on the ultrafiltration membrane and the reverse osmosis membrane. A booster pump also needs to be installed in front of the security filter 61.

[0061] The chemical dosing device 62 is used to add disinfectant to disinfect the sewage, effectively killing the microorganisms in the sewage, thereby reducing the pressure on the membrane system.

[0062] The pH adjustment device 63 adds a neutralizing solution according to the acidity and alkalinity of the sewage to keep the sewage neutral or weakly alkaline, thereby protecting the membrane material, preventing scaling on the surfaces of the ultrafiltration membrane and the reverse osmosis membrane, and improving the desalination efficiency.

[0063] A buffer tank 64 is added between the chemical dosing device 62 and the pH adjustment device 63. The buffer tank 64 is used to cache the sewage treated by the security filter 61 and at the same time serves as a dosing adjustment tank for the chemical dosing device 62 and the pH adjustment device 63. The buffer tank 64 also provides an adequate sewage treatment source for the liquid supply of the ultrafilter 5.

[0064] More specifically, a sewage tank 8 can be installed upstream of the pre-screening tank 1. The sewage tank 8 serves as a potential storage tank for sewage. A buffer mechanism is added on the front side of the pre-screening tank 1, which can temporarily store the sewage during the sewage treatment process to avoid the situation where the sewage volume is too large to be treated in time. A seawater inlet pipe 13 is provided on the sewage tank 8 or the pre-screening tank 1. The seawater inlet pipe 13 can introduce seawater into the sewage treatment system. When the ship lacks fresh water, seawater can be introduced to neutralize the sewage and at the same time supplement the water volume, realizing seawater desalination while treating the sewage and ensuring the fresh water supply of the ship.

Claims

1. A ship sewage treatment system using a photocatalyst, characterized in that: The invention comprises a pre-screening box (1), a flocculation box (2), a filter box (3) and an ultraviolet catalytic box (4) which are connected in sequence through pipelines. A rotary drum screen (11) is rotatably arranged in the pre-screening box (1) to cover its water inlet. At least one fin plate (12) is arranged on the outer side of the rotary drum screen (11). A plurality of folding plates (22) are staggeredly arranged in the flocculation box (2). A dosing machine (21) connected to the flocculation box (2) is arranged on one side of the flocculation box (2). At least three layers of filter materials with different particle sizes are arranged from top to bottom in the filter box (3). The particle size of the filter materials decreases from the upper layer to the lower layer. Partition filter plates (31) are arranged on the top of the top filter material, on the bottom of the bottom filter material and between each layer of filter material. A plurality of photocatalytic nets (41) are arranged in an array in the ultraviolet catalytic box (4). The top of the photocatalytic net (41) is hinged to the top of the ultraviolet photocatalytic box (4), and a connecting rod (44) is hinged on both sides of each photocatalytic net (41). The photocatalytic nets (41) on both sides and the ends of the ultraviolet photocatalytic box (4) are respectively provided with hinged non-Newtonian fluid dampers (42). At least one ultraviolet light source (43) is provided on each photocatalytic net (41). The axis of the rotary drum screen (11) is arranged along the length direction of the ship. The folding plates (22) are arranged in an array along the length direction of the ship. The photocatalytic nets (41) are arranged in an array along the width direction of the ship. The flocculation box (2) comprises a mixing zone and a reaction zone. The folding plates (22) are arranged in the reaction zone. The folding plates (22) are wavy plates or angled plates. The spacing between the folding plates (22) varies in width.

2. A ship sewage treatment system using a photocatalyst according to claim 1, characterized in that: The substrate of the photocatalytic net (41) is a light metal net, the light metal net has a titanium dioxide or modified titanium dioxide coating, the outside of the photocatalytic net (41) has a net frame (411), at least one support beam (412) is arranged in the middle of the photocatalytic net (41), and the ultraviolet light source (43) is mounted on the support beam (412).

3. A ship sewage treatment system using a photocatalyst according to claim 1, characterized in that: The ultraviolet catalytic box (4) is connected downstream in sequence to an ultrafilter (5) and a reverse osmosis filter (7) through pipelines.

4. A ship sewage treatment system using a photocatalyst according to claim 3, characterized in that: One or more of a security filter (61), a dosing device (62), and a pH adjustment device (63) are arranged upstream of the ultrafilter (5) and the reverse osmosis filter (7).

5. A ship sewage treatment system using a photocatalyst according to claim 1, characterized in that: A reflux pipe (46) is provided between the ultraviolet catalytic box (4) and the flocculation box (2), and a flow guide pipe (45) is provided between the pre-screening box (1) and the ultraviolet catalytic box (4).

6. A ship sewage treatment system using a photocatalyst according to claim 1, characterized in that: A sewage tank (8) is arranged upstream of the pre-screening box (1), and a seawater introduction pipe (13) is arranged on the sewage tank (8) or the pre-screening box (1).

7. A ship sewage treatment system using a photocatalyst according to claim 1, characterized in that: The rotary drum screen (11) comprises a cylindrical net, a plurality of reinforcing ribs are evenly arranged on the outer wall of the net, reinforcing rings are arranged at both ends of the net, a plurality of reinforcing ribs are connected between the reinforcing rings, and both ends of the rotary drum screen (11) are rotatably connected to the inner wall of the front screening box (1).

8. A ship sewage treatment system using a photocatalyst according to claim 1, characterized in that: At least one stirring paddle wheel (23) is arranged in the mixing zone, and the rotation axis of the stirring paddle wheel (23) is perpendicular to the water inlet and liquid inlet direction of the flocculation box (2).

9. A ship sewage treatment system using a photocatalyst according to claim 1, characterized in that: The filter box (3) is provided with a gravel layer with a diameter of 2-8 mm, a quartz sand layer with a diameter of 1.0-1.5 mm, and a quartz sand layer or anthracite layer with a diameter of 0.5-1.0 mm in a progressive manner from top to bottom.

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