Ship sewage treatment system applying photocatalyst

Abstract

The invention provides a ship sewage treatment system applying a photocatalyst, and mainly relates to the field of ship sewage treatment. A ship sewage treatment system applying a photocatalyst comprises a front screening box, a flocculation box, a filter box and an ultraviolet light catalysis box which are sequentially connected through a pipeline, a drum screen covering a water inlet of the front screening box is rotationally arranged in the front screening box, a plurality of folded plates are arranged in the flocculation box in a staggered mode, and a plurality of photocatalysis nets are arranged in the ultraviolet light catalysis box in an array mode. The tops of the photocatalysis nets are hinged to the top of the ultraviolet light catalysis box, and non-Newtonian fluid dampers are hinged to the two ends of the photocatalysis nets on the two sides and the two ends of the ultraviolet light catalysis box correspondingly. The sewage treatment device has the beneficial effects that a new technology of treating sewage by using a photocatalyst is integrated, rolling of a ship is used as power, so that the sewage can be in full contact with the photocatalyst to realize treatment, and the sewage treatment device is higher in adaptability, higher in treatment capacity, more energy-saving and capable of meeting the requirements of sewage treatment for the ship.

Description

Technical Field

[0001] The invention mainly relates to the field of ship sewage treatment, in particular to a ship sewage treatment system using a photocatalyst. Background Art

[0002] According to the provisions of my country's "Ship Water Pollutant Emission Control Standards", in inland rivers and sea areas within (inclusive) of 3 nautical miles from the nearest land, it is necessary to use ship-borne collection devices to collect, discharge into receiving facilities, and use ship-borne domestic sewage treatment devices to treat, and discharge during navigation after reaching the emission limit requirements. In sea areas within (inclusive) of 12 nautical miles beyond 3 nautical miles from the nearest land, it is crushed, disinfected and discharged under certain ship speed and discharge rate conditions. In sea areas beyond 12 nautical miles from the nearest land, it is discharged under certain ship speed and discharge rate conditions. However, for certain specific ships (scientific research ships) or certain specific sea areas (Baltic Sea, polar regions), ship sewage needs to be purified before it can be discharged. Among them, scientific research ships (such as our school's Dongfanghong 2, 3, Haida, etc.) need to undertake ocean-going scientific research missions including polar regions, which include several biochemical experimental projects, so sewage cannot be discharged directly into the ocean. It needs to be fully treated before it can be discharged to ensure that the marine environment is not polluted.

[0003] At present, the sewage treatment equipment used in ships mainly adopts the traditional filtration, flocculation and biological treatment processes. Since ships will continue to shake and sway when sailing on the ocean, the use of microorganisms to treat sewage usually requires a relatively calm environment and a relatively suitable temperature. This results in biological treatment usually failing to achieve the desired effect, especially when undertaking scientific research tasks in high-latitude areas. Biological treatment requires a lot of energy to maintain the working temperature of microorganisms, resulting in energy waste and the treatment effect is difficult to be satisfactory. Summary of the invention

[0004] In order to address the deficiencies of the prior art, the present invention provides a ship sewage treatment system using photocatalysts, which incorporates the new technology of photocatalyst treatment of sewage and uses the ship's rolling as power to enable the sewage to fully contact the photocatalyst for treatment. It has stronger adaptability, higher treatment capacity, and is more energy-efficient, and can meet the requirements for ship sewage treatment.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions: A ship sewage treatment system using photocatalysts comprises a pre-screening box, a flocculation box, a filter box and an ultraviolet catalytic box which are sequentially connected by pipelines. The pre-screening box filters out solid impurities in the sewage, the flocculation box aggregates and enlarges suspended particles in the sewage, or forms flocs, thereby accelerating the aggregation of particles, and the filter box is used to filter out flocculated impurities to reduce the turbidity in the sewage. The ultraviolet catalytic box decomposes dissolved organic matter and difficult-to-degrade particulate organic matter in the sewage through photocatalysts, and at the same time plays a sterilizing role, so that the sewage can meet the discharge standards.

[0006] A rotary drum screen covering the water inlet is rotatably arranged in the pre-screening box, and at least one fin is arranged on the outside of the rotary drum screen. The fin can drive the rotary drum screen to swing in coordination with the rolling of the ship, so that the debris in the rotary drum screen will not clog the mesh. A plurality of folding plates are staggered in the flocculation box, and the folding plates also cooperate with the rolling of the ship to make the sewage reciprocate in the channel between the folding plates, thereby achieving a stirring effect. A dosing machine connected to the flocculation box is arranged on one side of the flocculation box, and at least three layers of filter materials with different particle sizes are arranged from top to bottom in the filter box, and the particle size of the filter materials decreases from the upper layer to the lower layer. Partition filter plates are arranged on the top of the topmost filter material, the bottom of the bottommost filter material, and between each layer of filter material.

[0007] A plurality of photocatalytic nets are arranged in an array in the ultraviolet photocatalytic box. The top of the photocatalytic net is hinged with the top of the ultraviolet photocatalytic box. A connecting rod is hinged on both sides of each photocatalytic net. As the ship rolls, the sewage impacts the photocatalytic net, so that the photocatalytic net can swing back and forth with the water flow, playing a stirring role, so that the photocatalytic effect is better. The photocatalytic nets on both sides and the ends of the ultraviolet photocatalytic box are respectively provided with hinged non-Newtonian fluid dampers. The non-Newtonian fluid dampers are almost ineffective when the ship rolls slightly, ensuring the stirring effect under calm sailing conditions. The greater the ship rolls, the stronger the damping effect of the non-Newtonian fluid, thereby limiting the swing amplitude of the photocatalytic net, balancing the stirring effect in the ultraviolet photocatalytic box under different wave conditions, and protecting the photocatalytic net when the ship rolls more, avoiding damage due to the large swing amplitude and frequency of the photocatalytic net. At least one ultraviolet light source is arranged on each photocatalytic net, the axis of the drum screen is arranged along the length direction of the ship, the folding plate is arranged in an array along the length direction of the ship, and the photocatalytic net is arranged in an array along the width direction of the ship.

[0008] Preferably, the substrate of the photocatalytic net is a light metal net, the light metal net has a titanium dioxide or modified titanium dioxide coating, the outer side of the photocatalytic net has a net frame, at least one support beam is arranged in the middle of the photocatalytic net, and the ultraviolet light source is installed on the support beam. The arrangement of the net frame and the support beam both reinforces the photocatalytic net, and the substrate of the photocatalytic net is a light metal net, which also improves its strength, so that the photocatalytic net can be kept in a good use state.

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

[0010] Preferably, one or more of a safety 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 to provide pre-protection for the membrane system and ensure the service life of the membrane system.

[0011] Preferably, a reflux pipe is provided between the ultraviolet catalytic box and the flocculation box, and a guide pipe is provided between the pre-screening box and the ultraviolet catalytic 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 comprises a cylindrical cylinder net, a plurality of reinforcing ribs are evenly arranged on the outer wall of the cylinder net, reinforcing rings are arranged at both ends of the cylinder net, a plurality of reinforcing ribs are connected between the reinforcing rings, and both ends of the rotary drum screen are rotatably connected to the inner wall of the front 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 plate is arranged in the reaction area, the folding plate is a wavy plate or an angled plate, and the spacing between the folding plates varies in width. Through the passage with varying width, the sewage can be fully oscillated therein, achieving a better mixing effect, thereby improving both the flocculation efficiency and the flocculation effect.

[0015] Preferably, at least one stirring paddle wheel is arranged in the mixing zone, and the rotating shaft of the stirring paddle wheel is perpendicular to the water inlet direction of 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 anthracite layer filter material is arranged progressively from top to bottom in the filter box.

[0017] Compared with the prior art, the beneficial effects of the present invention are: The present invention adds a photocatalyst to the sewage treatment link of the ship to degrade the dissolved organic matter in the sewage, and can effectively kill bacteria and viruses in the sewage, so that the water quality can meet the discharge standard. The photocatalytic sewage treatment method replaces biological treatment, and the photocatalytic sewage treatment method is more adaptable and will not be affected by the shaking of the ship in the ocean. At the same time, the photocatalytic sewage treatment has a wider temperature range and can also work in high-latitude areas, effectively solving the sewage discharge problem during ship navigation.

[0018] The photocatalytic unit of the present invention adopts a photocatalytic net instead of a photocatalytic plate or tube structure. Although its efficiency is lower than that of the latter, it is not easy to be clogged and can be processed in a modular static manner without complicated maintenance, which is more conducive to the use environment of the ship.

[0019] Each sewage treatment unit of the present invention is modular and independently processed. After the sewage treatment is completed in the module, it is transferred to the next process for treatment, which is more suitable for the discontinuous sewage generation environment in the ship.

[0020] The present invention makes full use of the rolling of the ship as power, so that the sewage in the flocculation box and the ultraviolet catalytic box can be fully stirred, and the entire treatment process does not require external power, thus saving energy consumption.

[0021] The swing of the photocatalytic net in the ultraviolet photocatalytic box of the present invention is driven by the rolling of the ship, and the swing amplitude is limited by the non-Newtonian fluid damper, so that the swing amplitude of the photocatalytic net can be suppressed when the ship rolls greatly, so that the sewage stirring rate in the ultraviolet photocatalytic box can still maintain a relatively stable state when the ship rolls greatly, which is more convenient for monitoring the sewage treatment state in the ultraviolet photocatalytic box. At the same time, the non-Newtonian fluid damper limits the swing of the photocatalytic net, which can protect the photocatalytic net when the ship rolls greatly to avoid damage to the photocatalytic net. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Attached Figure 1 It is a structural schematic diagram of embodiment 1 of the present invention; Attached Figure 2 It is a structural schematic diagram of embodiment 2 of the present invention; Attached Figure 3 is a schematic structural diagram of Embodiment 3 of the present invention; Attached Figure 4 It is a schematic diagram of the structure of the pre-screening box of the present invention; Attached Figure 5 This is a schematic diagram of the internal structure of the flocculation box of the present invention when viewed from above; Attached Figure 6 It is a schematic diagram of a partial cross-sectional structure of a flocculation box of the present invention in a left-side state; Attached Figure 7This is a schematic diagram of the cross-sectional structure of the filter box of the present invention; Attached Figure 8 It is a schematic diagram of the internal structure of the ultraviolet photocatalytic box of the present invention; Attached Fig. 9 It is a schematic diagram of the structure of the photocatalytic network of the present invention; Attached Fig.10 It is a schematic diagram of the monomer structure of the photocatalytic network of the present invention.

[0023] Numbers shown in the accompanying drawings: 1. Pre-screening box; 2. Flocculation box; 3. Filter box; 4. Ultraviolet photocatalytic box; 5. Ultrafilter; 7. Reverse osmosis filter; 8. Sewage tank; 11. Drum screen; 12. Fins; 13. Seawater inlet pipe; 21. Dosing machine; 22. Folding plate; 23. Agitator paddle wheel; 31. Partition filter plate; 41. Photocatalytic net; 42. Non-Newtonian fluid damper; 43. Ultraviolet light source; 44. Connecting rod; 45. Guide pipe; 46. Reflux pipe; 411. Net frame; 412. Support beam; 61. Security filter; 62. Dosing device; 63. pH adjustment device; 64. Buffer tank. DETAILED DESCRIPTION

[0024] The present invention will be further described with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended 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 may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the application. Embodiment 1:

[0025] This embodiment provides a ship sewage treatment system using a photocatalyst, which is used to treat domestic sewage and experimental wastewater generated by ships to meet emission standards and avoid pollution to the ocean.

[0026] The device includes 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. The pre-screening box 1 is used as a temporary storage place for sewage. After use, the ship's water is collected in the pre-screening box 1 through complex pipelines. The sewage is filtered through the pre-screening box 1 for the first time, and the solid insoluble impurities therein are filtered out, and then cleaned during the subsequent shutdown and maintenance. Specifically, in this embodiment, the filter screen of the pre-screening box 1 adopts a drum screen 11 covering its water inlet. The drum screen 11 itself is rotatably installed with the inner wall of the pre-screening box 1. The outer wall of the drum screen 11 is the filtering part, which can trap solid impurities inside the screen. Specifically, in order to prevent the bottom of the screen from being blocked by debris over time and affecting the filtering effect, the rotating installation structure of the drum screen 11 in this embodiment can swing the drum screen 11 with the impact of the water flow, thereby achieving a certain backwashing effect and slowing down the situation of the screen hole being blocked.

[0027] Specifically, the drum screen 11 includes a cylindrical cylinder net, and a number of reinforcing ribs are evenly arranged on the outer wall of the cylinder net. The reinforcing ribs reinforce the cylinder net to improve its overall strength and prevent deformation and damage caused by the accumulation of solid pollutants and the scouring of water flow. Reinforcing rings are arranged at both ends of the cylinder net, and a plurality of reinforcing ribs are connected between the reinforcing rings. The reinforcing rings also play the role of reinforcing the cylinder net. At the same time, the reinforcing rings also serve as a rotatably installed part, and are rotatably connected to the inner wall of the front screening box 1. More specifically, if the length span of the drum screen 11 is large, several reinforcing rings can be selectively added to the middle part of the drum screen 11 to further optimize the strength of the drum screen 11.

[0028] Furthermore, in this embodiment, both ends of the drum screen 11 are rotatably connected to the inner wall of the front screening box 1 through plane bearings, thereby improving the rotation stability of the drum screen 11, ensuring the installation firmness of the drum screen 11, and ensuring the filtering effect of impurities in sewage.

[0029] At least one fin 12 is arranged on the outside of the drum screen 11. In this embodiment, the fin 12 is installed on the reinforcing ribs. The axis of the drum screen 11 is arranged along the length direction of the ship. The rolling of the ship will cause the sewage in the pre-screening box 1 to vibrate, thereby flushing the fin 12, providing power for the swing of the drum screen 11, avoiding the blocking effect of debris on the screen holes of the drum screen 11, and improving the operating time of the pre-screening device.

[0030] The water outlet of the pre-screening box 1 is connected to the water inlet of the flocculation box 2 through a pipe, and a water pump is connected in series on the connecting pipe as a power source to guide the sewage in the pre-screening box 1 into the flocculation box 2. The flocculation box 2 includes a mixing area and a reaction area, and 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 water inlet and liquid inlet direction of the flocculation box 2.

[0031] A dosing machine 21 connected to the flocculation box 2 is arranged on one side of the flocculation box 2. The dosing machine 21 is provided with a dosing pump. The dosing pump adds the flocculation agent into the flocculation box 2 through a hose. Specifically, the flocculation agent is added simultaneously 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 dosing port of the flocculation box 2 is located on one side of the water inlet. When the sewage is injected, the dosing port is simultaneously injected with the flocculation agent, and the two begin to mix at the same time of injection. 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 more fully mixed, so as to improve the flocculation effect of suspended matter and colloidal substances in the sewage.

[0032] The folding plates 22 are arranged in the reaction zone, and the folding plates 22 are arranged in an array along the length direction of the ship, and a channel extending along the width direction of the ship is formed between adjacent folding plates 22. The folding plates 22 are wavy plates or angled plates, and the spacing between the folding plates 22 varies in width. Through the rolling of the ship, the sewage in the reaction zone is disturbed back and forth in the channel between the folding plates 22. Through the variation in the width between the folding plates 22, the sewage can be more fully mixed in the reaction zone. The rolling of the ship serves as a power, so that the disturbance of the sewage forms a stirring effect, accelerates the flocculation of suspended matter and colloidal substances, improves the flocculation effect, and shortens the flocculation time.

[0033] The flocculation box 2 and the filter box 3 are connected by a pipe, and a pump body is connected in series on the pipe. The sewage in the flocculation box 2 can be introduced into the filter box 3 through the pump body. The water inlet of the filter box 3 is located at the top, and the water outlet of the filter box 3 is located at the bottom. At least three layers of filter materials with different particle sizes are arranged from top to bottom in the filter box 3, and the particle size of the filter material decreases from the upper layer to the lower layer. Partition filter plates 31 are arranged at the top of the topmost filter material, the bottom of the bottommost filter material, and between each layer of filter material. The partition filter plate 31 is arrayed with filter holes that are no larger than the adjacent filter material layer. The partition filter plate 31 restricts the filter material to avoid mixing and scattering of the filter material when the ship rolls and pitches, thereby ensuring the filtering effect in an unstable state.

[0034] Specifically, the filter box 3 is a cylindrical structure, and a ring platform corresponding to the partition filter plate 31 is arranged in the filter box 3, and the partition filter plate 31 is detachably mounted on the ring platform by bolts.

[0035] Specifically, in this embodiment, a gravel layer with a thickness of 600-1000mm and a diameter of 2-8mm, a quartz sand layer with a thickness of 400-600mm and a diameter of 1.0-1.5mm, and a quartz sand layer or anthracite layer filter material with a thickness of 400-600mm and a diameter of 0.5-1.0mm are arranged progressively from top to bottom in the filter box 3. The gravel layer filter material on the top layer filters large-diameter flocculated impurities and at the same time has the effect of dispersing the water flow, so that the sewage can be evenly dispersed to the middle and lower filter materials. The quartz sand layer filter material on the middle layer continues to filter the flocculated impurities of the next order of magnitude, and the quartz sand or anthracite layer filter material on the lower layer filters the small-diameter flocculated impurities, thereby completely filtering the flocculated impurities in the sewage without affecting the subsequent sewage treatment steps.

[0036] Specifically, in order to make the sewage more dispersed in the filter box 3 and to make the removal of flocculated impurities more uniform, a conical disperser is installed on the top of the filter box 3. The diameter of the disperser is about two-thirds of the filter box 3. The water inlet of the filter box 3 is located at the center of the top of the disperser. Through the spreading and buffering effect of the disperser, the sewage can be evenly dispersed on the filter material, and the impact effect on the filter material can be reduced, so that the filter box 3 can better remove flocculated impurities.

[0037] The water outlet at the bottom of the filter box 3 is connected to the water inlet of the ultraviolet catalytic box 4 through a pipe, and the pump body is connected in series to the pipe. The bottom of the filter box 3 has a certain space as a temporary storage position for the filtered sewage, and the pump body can guide the filtered sewage into the ultraviolet catalytic box 4.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The photocatalytic nets 41 on both sides and the two ends of the ultraviolet photocatalytic box 4 are respectively provided with hinged non-Newtonian fluid dampers 42. The non-Newtonian fluid damper 42 can balance the amplitude of the ship's roll. When the sea surface is relatively calm and the ship's roll is small, the water flow oscillation generated by the roll will not have too much impact on the photocatalytic net 41. At this time, the non-Newtonian fluid damper 42 does not work, so that the photocatalytic net 41 can swing back and forth in a small range with the impact of the water flow, play a role in stirring and mixing, and accelerate the purification of water quality. When the sea surface has large wind and waves and the ship rolls greatly, the water flow oscillation generated by the roll has a greater impact on the photocatalytic net 41. At this time, the swing amplitude and strength of the photocatalytic net show an increasing trend. After the non-Newtonian fluid damper 42 is subjected to the instantaneous overload impact force, it presents a rigid state, which can suppress the swing amplitude of the photocatalytic net 41 and prevent the photocatalytic net 41 from being damaged by large-scale rapid swings. At the same time, the swing amplitude of the photocatalytic net 41 is balanced through the limiting effect of the non-Newtonian fluid damper 42, that is, the sewage stirring efficiency in the ultraviolet photocatalytic box 4 is balanced, thereby balancing the sewage treatment rate in the ultraviolet photocatalytic box 4 to a certain extent, so that when the rolling amplitude of the ship is inconsistent, the sewage treatment time remains basically consistent.

[0042] In this embodiment, the sewage in the ultraviolet photocatalytic box 4 is regularly sampled, and the concentration changes of pollutants in the sewage, such as chemical oxygen demand (COD), biochemical oxygen demand (BOD), total organic carbon (TOC) and other indicators, are monitored by regular sampling to evaluate the effect of photocatalytic treatment. After the treatment meets the standards, the treated sewage is discharged into the ocean through the drain outlet of the ultraviolet photocatalytic box 4. Embodiment 2:

[0043] When the proportion of biochemical sewage used for experiments in ship sewage is high, there are more difficult-to-degrade organic matter and soluble organic matter (DOM) in the sewage. These substances are difficult to remove by flocculation. At the same time, after photocatalytic treatment, these organic matter will still be decomposed into small molecular organic matter, which may not meet the emission standards. Based on this situation, on the basis of Example 1, a reflux pipe 46 is set between the ultraviolet catalytic box 4 and the flocculation box 2, and a guide pipe 45 is set between the ultraviolet catalytic box 4 and the pre-screening box 1. The pump body is connected in series on the reflux pipe 46 and the guide pipe 45. Specifically, the reflux pipe 46 is connected to the outlet pipe of the ultraviolet catalytic box 4 through a tee, and the two can share the same pump body. The end of the reflux pipe 46 is connected to the water inlet of the flocculation box 2 through a tee. Valve bodies are installed on the reflux pipe 46 and the outlet pipe of the ultraviolet catalytic box 4 to regulate the flow direction of sewage. The flow guide pipe 45 is connected to the outlet pipe of the pre-screening box 1 through a tee, and the two can share the same pump body. The outlet pipe of the pre-screening box 1 is connected to the water inlet of the flocculation box 2, and the end of the flow guide pipe 45 is connected to the water inlet of the ultraviolet photocatalytic box 4 through a tee. Valve bodies are installed on the outlet pipes of the flow guide pipe 45 and the pre-screening box 1 to regulate the flow direction of the sewage.

[0044] The guide pipe 45 is used to directly guide the sewage into the ultraviolet photocatalytic box 4 for preliminary photocatalytic treatment, and the return pipe 46 is used to return the sewage treated by preliminary photocatalytic treatment to the flocculation box 2 for flocculation and sedimentation. After the flocculation and sedimentation are completed, the sewage enters the ultraviolet photocatalytic box 4 for a second time for secondary photocatalytic treatment and sterilization treatment to improve the efficiency and effect of sewage treatment.

[0045] 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 box 4 and the service life of the photocatalytic net 41.

[0046] If the turbidity of the sewage is too high, the sewage can first pass through the flocculation tank 2 for flocculation and sedimentation, then enter the filter box 3 for filtration, and then return to the flocculation tank 2 after photocatalytic treatment to repeat the above process. The experimental biochemical sewage can be completely purified through at least two flocculation sedimentation-filtration-photocatalysis processes. Embodiment 3:

[0047] When a ship needs to carry out a long scientific research mission and cannot dock for replenishment in time, the sewage treatment system can be used to fully treat the sewage. The treated sewage can be used for non-drinking purposes or as a source of drinking water after deep purification.

[0048] Specifically, based on the sewage treatment system of Example 1, in this embodiment, the ultraviolet photocatalytic box 4 is connected to the ultrafilter 5 and the reverse osmosis filter 7 in sequence through a pipeline downstream. A booster pump is added to 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, which can filter out suspended particles, colloids, most bacteria and some viruses, etc., so as to serve as a pre-process of 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 for flushing toilets and decks. A booster pump is also installed on the front side of the reverse osmosis filter 7 to increase the reverse osmosis filter 7 so that 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 soluble solids, inorganic salts, organic matter, bacteria, viruses, etc. in the water, and the desalination rate is generally greater than 98%, and the turbidity is controlled within 0.1NTU, which has reached the quality of high-purity water and can be used as drinking water.

[0049] The application of this equipment for emergency treatment of marine sewage can provide sufficient water for ships when they are engaged in scientific research for a long time and cannot dock for replenishment. When the ship docks for repairs, the membrane system needs to be backwashed to maintain its stable operation.

[0050] More specifically, one or more of the security filter 61, the dosing device 62, and the pH adjustment device 63 can be installed in front of the ultrafilter 5, and the selection can be made according to the state of the ship's sewage. The security filter 61 (precision filter) is the last insurance process before the membrane treatment system. It can filter the particulate matter generated by the photocatalytic process or the microbial impurities that cannot be effectively removed, and reduce the pressure of the ultrafiltration membrane and the reverse osmosis membrane. A booster pump also needs to be installed in front of the security filter 61.

[0051] The dosing device 62 is used to add disinfectant to disinfect the sewage, so that the microorganisms in the sewage are effectively killed, thereby reducing the pressure of the membrane system.

[0052] The pH adjustment device 63 adds a neutralizing solution according to the pH value of the sewage to keep the sewage neutral or weakly alkaline, thereby protecting the membrane material, preventing scaling on the surface of the ultrafiltration membrane and the reverse osmosis membrane, and improving the desalination efficiency.

[0053] A buffer tank 64 is added between the dosing device 62 and the pH adjusting device 63. The buffer tank 64 is used to buffer the sewage treated by the security filter 61 and serves as a dosing adjustment tank for the dosing device 62 and the pH adjusting device 63. The buffer tank 64 also provides a sufficient sewage treatment source for the liquid supply of the ultrafilter 5.

[0054] More specifically, a sewage tank 8 can be installed upstream of the pre-screening box 1. The sewage tank 8 serves as a potential temporary storage box for sewage. A buffer mechanism is added to the front side of the pre-screening box 1 to temporarily store sewage during sewage treatment to avoid excessive sewage that cannot be treated in time. A seawater inlet pipe 13 is provided on the sewage tank 8 or the pre-screening box 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 replenish water at the same time. The desalination of seawater is achieved while the sewage is being treated, thereby 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. The top of the top filter material, the bottom of the bottom filter material, and each layer of filter material are provided with a A partition filter plate (31) is arranged, 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), hinged non-Newtonian fluid dampers (42) are arranged at both ends of the photocatalytic nets (41) and the ultraviolet photocatalytic box (4), at least one ultraviolet light source (43) is arranged 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, and the photocatalytic nets (41) are arranged in an array along the width direction of the ship.

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: The flocculation box (2) comprises a mixing zone and a reaction zone, the folded plates (22) are arranged in the reaction zone, the folded plates (22) are wavy plates or angled plates, and the spacing between the folded plates (22) varies in width.

9. A ship sewage treatment system using a photocatalyst according to claim 8, 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).

10. 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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