A multi-stage water treatment discharge system

Abstract

The application discloses a multi-stage water treatment and discharge system for a cruise ship bilge water, which comprises a sewage well suction, a sewage treatment part, a first discharge control valve, a second discharge control valve and a clean bilge water collecting tank, the sewage well suction is communicated with the sewage treatment part, the sewage treatment part is communicated with the first discharge control valve, the first discharge control valve is communicated with the second discharge control valve or the clean bilge water collecting tank, the clean bilge water collecting tank is communicated with the second discharge control valve, and the second discharge control valve is communicated with the outside of a ship side. Compared with the prior art, the multi-stage water treatment and discharge system uses a heating and volume reduction mode, the bilge water oil filter has lower working load and longer working life, and under the condition of meeting the operation requirement, unnecessary cabin arrangement is reduced, and valuable engine room space is saved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a multi-stage water treatment and discharge system. Background Technology

[0002] Due to the operational characteristics of cruise ships, there are often instances where they remain anchored in a particular sea area for extended periods during the day. During this anchorage, equipment that generates bilge water, such as the main generator, needs to continue operating, producing a significant amount of bilge water that requires timely treatment. According to Article 15 of Chapter 3 of Annex I to the International Convention for the Prevention of Pollution (MARPOL 73 / 78), the following requirements apply to bilge water treatment and discharge: 1. The bilge water must be treated by an oil filtration system and meet a discharge standard of 15 ppm; 2. The discharge must meet the operational conditions of the ship while it is sailing.

[0003] In addition, when cruise ships are sailing in certain special sea areas, such as polar regions and special economic zone sea areas, where there are higher regulatory requirements and indicator requirements for emissions, the only operational strategy they can adopt is to collect bilge water.

[0004] Due to space constraints, cruise ship engine rooms and double bottoms cannot be equipped with large bilge water storage tanks like those on ordinary cargo ships to store bilge water generated during berthing. Therefore, certain volume reduction methods are necessary. Currently, some ships use heating of the bilge water collection tanks to reduce volume. However, this method on cruise ships increases the workload on bilge water filters, reducing their lifespan. Furthermore, the water vapor generated during the heating and volume reduction process still contains some oil, which can pollute the environment at the exhaust end and the paintwork. Therefore, this method is inappropriate for cruise ships, regardless of whether the exhaust end is located on the passenger deck or the open deck. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing bilge water filter, which has high working load and short service life, and the water vapor generated during the heating and volume reduction process still contains some oil, thus causing pollution to the environment at the discharge end and the coating. In addition, there is no suitable installation location when it is used on cruise ships. The present invention provides a multi-stage water treatment discharge system.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] A multi-stage water treatment and discharge system is characterized in that the multi-stage water treatment and discharge system is used for bilge water of cruise ships, and the multi-stage water treatment and discharge system includes a sewage well suction port, a sewage treatment unit, a first discharge control valve, a second discharge control valve, and a clean bilge water collection tank.

[0008] The sewage well suction port is connected to the sewage treatment unit, the sewage treatment unit is connected to the first discharge control valve, the first discharge control valve is connected to the second discharge control valve or the clean bilge water collection tank, the clean bilge water collection tank is connected to the second discharge control valve, and the second discharge control valve leads to the outside of the ship;

[0009] When the multi-stage water treatment and discharge system is in normal discharge mode, the first discharge control valve controls the bilge water from the wastewater treatment unit to flow to the second discharge control valve and outwards;

[0010] When the multi-stage water treatment and discharge system is in the restricted discharge mode, the first discharge control valve controls the flow of bilge water from the wastewater treatment unit to the clean bilge water collection tank.

[0011] When the multi-stage water treatment and discharge system changes from the restricted discharge mode to the clean bilge water collection tank emptying mode, the second discharge control valve opens to discharge the bilge water in the clean bilge water collection tank to the outside.

[0012] In this design, bilge water, after treatment by the wastewater treatment unit, is stored or discharged overboard under three different modes of the multi-stage water treatment and discharge system. In normal discharge mode, it is discharged directly through the first and second discharge control valves. In restricted discharge mode, it is stored in a clean bilge water collection tank through the first discharge control valve. In the clean bilge water collection tank emptying mode, the bilge water in the collection tank is discharged overboard. Compared to existing technologies that use heating to reduce volume, the bilge water filter has a lower workload and a longer service life. Furthermore, while meeting operational requirements, it reduces unnecessary compartment layout and saves valuable engine room space.

[0013] Preferably, the wastewater treatment unit includes a bilge water pretreatment cabinet and a bilge water oil filter, the bilge water pretreatment cabinet being upstream of the bilge water oil filter, and the bilge water pretreatment cabinet and the bilge water oil filter including pipes leading to the waste oil tank.

[0014] In this scheme, the bilge water is first introduced from the sewage well to the bilge water pretreatment tank in the sewage treatment department for preliminary treatment, and then further treated by the bilge water oil filter. Using this scheme can reduce the working pressure of the bilge water oil filter and thus extend its service life. At the same time, the two-stage treatment can achieve better oil filtration effect.

[0015] Preferably, a bilge water collection pump is also provided on the pipeline between the sewage well suction port and the sewage treatment unit. The inlet of the bilge water collection pump is connected to the sewage well suction port, and the outlet of the bilge water collection pump is connected to the sewage treatment unit.

[0016] And / or, a clean bilge water discharge pump is also provided on the pipeline between the clean bilge water collection tank and the second discharge control valve, the inlet of the clean bilge water discharge pump is connected to the clean bilge water collection tank, and the outlet of the clean bilge water discharge pump is connected to the second discharge control valve.

[0017] In this scheme, the bilge water collection pump transports the bilge water in the sludge well to the sludge treatment department for treatment, and the clean bilge water discharge pump discharges the bilge water from the clean bilge water collection tank to the outside. The two pumps in this scheme provide power for the bilge water in the system.

[0018] Preferably, the first emission control valve and the second emission control valve are three-way control valves.

[0019] In this scheme, the two discharge control valves are three-way control valves. Specifically, the first discharge control valve uses a diversion control valve, and the second discharge control valve uses a confluence control valve. Using this scheme, the bilge water can be manipulated at the first control valve to choose whether to store or discharge it overboard, and at the same time, the bilge water can be manipulated at the second control valve to choose whether to discharge it.

[0020] Preferably, the multi-stage water treatment and discharge system also includes a control unit for receiving discharge signals from the chamber and sewage well level switch signals.

[0021] In this scheme, the control unit receives the ship's hull status information as a basis for further control of the bilge water flow direction.

[0022] Preferably, the emission signal includes a positioning signal and a speed signal. The positioning signal is used to distinguish whether the cruise ship's cabins are in an area without emission restrictions, and the speed signal is used to distinguish whether the cruise ship is sailing or stationary. The emission signal is considered permissible when the positioning signal indicates that the cruise ship's cabins are in an area without emission restrictions and the speed signal indicates that the cruise ship is sailing, corresponding to the multi-stage water treatment emission system switching to the normal emission mode and the clean bilge water collection tank emptying mode. In other states, the emission signal is considered non-permissible, corresponding to the multi-stage water treatment emission system switching to the restricted emission mode.

[0023] In this scheme, the emission signal is divided into two parts: positioning signal and speed signal. When the positioning signal is in an area without emission restrictions and the speed signal is when the cruise ship is sailing, the emission signal will be processed by the control unit as permissible for emission. In other states, the emission signal will be processed by the control unit as non-permissible for emission. The control unit can analyze the two directly obtainable signals and determine whether the treated bilge water can be discharged. The two signals also correspond to two categories and three processing modes, which is conducive to the automated control of the multi-stage water treatment and emission system.

[0024] Preferably, the signal of the sewage well level switch is located at the sewage well where the sewage well suction port is located, and the signal is issued when the liquid level in the sewage well is higher than the sewage well level switch.

[0025] When the control unit receives a signal from the sewage well level switch, the control unit controls the bilge water collection pump to pump the bilge water in the sewage well to the sewage treatment unit.

[0026] In this solution, a sewage well level switch and control unit are used together to control the bilge water collection pump only when the sewage well water level is high, thereby achieving automated treatment of bilge water in the sewage well and reducing the pump's operating time while ensuring that sewage does not overflow.

[0027] Preferably, after treating the bilge water, the wastewater treatment unit sends a treatment signal to the control unit. Upon receiving the treatment signal, the control unit determines the discharge signal. If the discharge signal is non-dischargeable, the control unit sends a signal to control the first discharge control valve to open to the clean bilge water collection tank, i.e., the multi-stage water treatment discharge system switches to the restricted discharge mode. If the discharge signal is permissible, the control unit sends a signal to control the first discharge control valve to open to the second discharge control valve, i.e., the multi-stage water treatment discharge system begins to switch to the normal discharge mode.

[0028] Specifically, after the wastewater is treated by the bilge water filter, the wastewater treatment department takes on the function of sending signals to the control unit.

[0029] The conversion of the multi-stage water treatment and discharge system to restricted discharge mode and normal discharge mode here is the beginning of the conversion process, not the result of the conversion being completed.

[0030] In this solution, after the wastewater treatment unit finishes treating the bilge water, the control unit determines whether the entire multi-stage water treatment and discharge system should switch to restricted discharge mode or normal discharge mode, thereby controlling the direction of the first discharge control valve. The bilge water filter is responsible for sending signals to the control unit after treating the bilge water. The process of controlling the flow direction of the bilge water using this solution is fully automated and will not cause bilge water accumulation in the treatment unit, reducing the working pressure of the bilge water filter and increasing its service life.

[0031] Preferably, when the clean bilge water collection tank contains bilge water, it sends a signal to the control unit. The control unit determines the discharge signal, and when the discharge signal indicates that the bilge water can be discharged, the control unit sends a signal to control the clean bilge water discharge pump to pump the bilge water from the clean bilge water collection tank to the second discharge control valve.

[0032] And / or, the second discharge control valve senses the bilge water coming from the first discharge control valve and the clean bilge water collection tank and sends a signal to the control unit; after the control unit determines that the discharge signal is dischargeable, it opens the second discharge control valve, that is, the multi-stage water treatment discharge system switches to the normal discharge mode and / or the bilge water collection tank emptying mode; after the control unit determines that the discharge signal is not dischargeable, it keeps the second discharge control valve closed, that is, the multi-stage water treatment discharge system switches to the restricted discharge mode.

[0033] In this solution, when the bilge water collection tank contains bilge water, it sends a signal to the control unit to determine the discharge signal. When bilge water can be discharged, the control unit operates the clean bilge water discharge pump to deliver the bilge water to the second discharge control valve. This solution controls the amount of bilge water in the clean bilge water collection tank, preventing excessive accumulation. In this solution, after the second discharge control valve senses bilge water from the first discharge control valve or from the clean bilge water collection tank, it sends a signal to the control unit. After determining the discharge signal, the control unit opens the second discharge control valve when discharge is possible and closes it when discharge is not possible. This completes the conversion of the multi-stage water treatment discharge system to restricted discharge mode, normal discharge mode, and / or bilge water collection tank emptying mode. The restricted discharge mode and normal discharge mode conflict, as do the restricted discharge mode and bilge water collection tank emptying mode. However, the normal discharge mode can exist simultaneously with or independently of the bilge water collection tank emptying mode. Using this solution, the operating mode of the multi-stage water treatment discharge system can be quickly switched when discharge and non-discharge conditions change, ensuring the stability and efficiency of the system.

[0034] Preferably, there is also a discharge monitoring unit on the pipeline from the second discharge control valve to the outside. The discharge monitoring unit monitors and records the flow rate and oil concentration, and sends the recorded information to the control unit. When the oil concentration of the bilge water from the second discharge control valve is too high, the discharge monitoring unit automatically stops discharging to the outside and directs the bilge water to the sewage treatment unit.

[0035] In this solution, a discharge monitoring unit is used to monitor and record the discharged bilge water and oil concentration, and send the data to the control center. When the liquid oil concentration is too high, the discharge to the outside can be stopped and the bilge water can be sent to the sewage treatment department for secondary treatment. Using this solution can further ensure that the bilge water can be discharged, and the recorded data can be analyzed by maintenance personnel, which is beneficial for targeted maintenance when the system fails.

[0036] The significant advantages of this invention are as follows: after treatment by the wastewater treatment unit, bilge water is stored or discharged overboard in three different modes of the multi-stage water treatment and discharge system. In normal discharge mode, it is discharged directly through the first and second discharge control valves. In restricted discharge mode, it is stored in a clean bilge water collection tank through the first discharge control valve. In the clean bilge water collection tank emptying mode, the bilge water in the clean bilge water collection tank is discharged overboard. Compared to the existing technology that uses heating to reduce volume, the bilge water filter has a lower workload and a longer service life. Furthermore, while meeting operational requirements, it reduces unnecessary compartment layout and saves valuable engine room space. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a multi-stage water treatment and discharge system design scheme according to the present invention.

[0038] Explanation of reference numerals in the attached drawings: 1. Sewage well suction port; 2. Sewage treatment unit; 21. Bilge water pretreatment cabinet; 22. Bilge water oil filter; 3. First discharge control valve; 4. Second discharge control valve; 5. Clean bilge water collection cabinet; 6. Control unit; 7. Discharge signal; 71. Positioning signal; 72. Speed ​​signal; 8. Sewage well level switch; 9. Bilge water collection pump; 10. Clean bilge water discharge pump; 11. Discharge monitoring unit. Detailed Implementation

[0039] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0040] Example

[0041] like Figure 1As shown, a multi-stage water treatment and discharge system for cruise ship bilge water includes a sludge well suction port 1, a sludge treatment unit 2, a first discharge control valve 3, a second discharge control valve 4, and a clean bilge water collection tank 5. The sludge well suction port 1 is connected to the sludge treatment unit 2, the sludge treatment unit 2 is connected to the first discharge control valve 3, the first discharge control valve 3 is connected to the second discharge control valve 4 or the clean bilge water collection tank 5, and the clean bilge water collection tank 5 is connected to the second discharge control valve 4. The second discharge control valve 4 leads to the outside of the ship. When the water treatment discharge system is in normal discharge mode, the first discharge control valve 3 controls the flow of bilge water from the wastewater treatment unit 2 to the second discharge control valve 4, and then to the outside. When the multi-stage water treatment discharge system is in restricted discharge mode, the first discharge control valve 3 controls the flow of bilge water from the wastewater treatment unit 2 to the clean bilge water collection tank 5. When the multi-stage water treatment discharge system changes from restricted discharge mode to clean bilge water collection tank 5 emptying mode, the second discharge control valve 4 opens to discharge the bilge water in the clean bilge water collection tank 5 to the outside. After being treated by the wastewater treatment unit 2, the bilge water is stored or discharged to the outside in the three different modes of the multi-stage water treatment discharge system. In normal discharge mode, it is discharged directly through the first discharge control valve 3 and the second discharge control valve 4. In restricted discharge mode, it is stored in the clean bilge water collection tank 5 through the first discharge control valve 3. In clean bilge water collection tank 5 emptying mode, the bilge water in the clean bilge water collection tank 5 is discharged to the outside. Compared to the existing technology that uses heating to reduce volume, the bilge water filter 22 has a lower workload and a longer service life. It also reduces unnecessary compartment layout and saves valuable cabin space while meeting operational requirements.

[0042] like Figure 1 As shown, the wastewater treatment unit 2 includes a bilge water pretreatment tank 21 and a bilge water oil filter 22. The bilge water pretreatment tank 21 is upstream of the bilge water oil filter 22. The bilge water pretreatment tank 21 and the bilge water oil filter 22 include pipes leading to the waste oil tank, which can reduce the working pressure of the bilge water oil filter 22 and thus extend its service life. At the same time, two-stage treatment can achieve better oil filtration effect.

[0043] like Figure 1 As shown, there is also a bilge water collection pump 9 on the pipeline between the sewage well suction port 1 and the sewage treatment section 2. The inlet of the bilge water collection pump 9 is connected to the sewage well suction port 1, and the outlet of the bilge water collection pump 9 is connected to the sewage treatment section 2. There is also a clean bilge water discharge pump 10 on the pipeline between the clean bilge water collection tank 5 and the second discharge control valve 4. The inlet of the clean bilge water discharge pump 10 is connected to the clean bilge water collection tank 5, and the outlet of the clean bilge water discharge pump 10 is connected to the second discharge control valve 4. The two pumps provide power for the bilge water in the system.

[0044] like Figure 1As shown, the first discharge control valve 3 and the second discharge control valve 4 are three-way control valves. Specifically, the first discharge control valve 3 uses a diversion control valve and the second discharge control valve 4 uses a confluence control valve. The bilge water can be manipulated at the first control valve to select whether to store or discharge it overboard, and at the same time, the bilge water can be manipulated at the second control valve to select whether to discharge it.

[0045] like Figure 1 As shown, the multi-stage water treatment and discharge system also includes a control unit 6, which receives signals from the in-chamber discharge signal 7 and the sewage well level switch 8 as a basis for further controlling the direction of the bilge water flow.

[0046] like Figure 1 As shown, the emission signal 7 includes a positioning signal 71 and a speed signal 72. The positioning signal 71 is used to distinguish whether the cruise ship's cabin is in an area without emission restrictions, and the speed signal 72 is used to distinguish whether the cruise ship is sailing or stationary. The emission signal 7 is allowed to be emitted when the positioning signal 71 indicates that the cruise ship's cabin is in an area without emission restrictions and the speed signal 72 indicates that the cruise ship is sailing. This corresponds to the multi-stage water treatment emission system switching to normal emission mode and clean bilge water collection tank 5 emptying mode. In other states, the emission signal 7 is not allowed to be emitted, and the multi-stage water treatment emission system switches to restricted emission mode. The control unit 6 can analyze the two directly obtainable signals and determine whether the treated bilge water can be emitted. The two signals also correspond to two types of three treatment modes, which is beneficial for the multi-stage water treatment emission system to complete automated control.

[0047] like Figure 1 As shown, the signal of the sewage well level switch 8 is sent at the sewage well where the sewage well suction port 1 is located. The signal is sent when the liquid level in the sewage well is higher than the sewage well level switch 8. When the control unit 6 receives the signal of the sewage well level switch 8, the control unit 6 controls the bilge water collection pump 9 to pump the bilge water in the sewage well to the sewage treatment unit 2. By using the sewage well level switch 8 and the control unit 6 in cooperation, the bilge water collection pump 9 is controlled to work only when the water level in the sewage well is high. This realizes the automated treatment of the bilge water in the sewage well and reduces the working time of the pump body while ensuring that the sewage does not overflow.

[0048] like Figure 1As shown, after treating the bilge water, the wastewater treatment unit 2 sends a treatment signal to the control unit 6. Upon receiving the treatment signal, the control unit 6 determines the discharge signal 7. If the discharge signal is not permitted, the control unit 6 sends a signal to control the first discharge control valve 3 to open the clean bilge water collection tank 5, thus switching the multi-stage water treatment discharge system to a restricted discharge mode. If the discharge signal is permitted, the control unit 6 sends a signal to control the first discharge control valve 3 to open the second discharge control valve 4, thus switching the multi-stage water treatment discharge system to a normal discharge mode. Specifically, after the wastewater has been treated by the bilge water filter 22, the bilge water filter 22 takes on the function of sending signals to the control unit 6. In particular... Here, the conversion of the multi-stage water treatment discharge system to restricted discharge mode and normal discharge mode is a process of entering the conversion process, not a result of the conversion being completed. After the wastewater treatment unit 2 has finished treating the bilge water, the control unit 6 determines whether the entire multi-stage water treatment discharge system has entered the restricted discharge mode or the normal discharge mode, thereby controlling the direction of the first discharge control valve 3. The bilge water filter 22 is responsible for sending signals to the control unit 6 after treating the bilge water. The process of controlling the flow direction of the bilge water is fully automated and there is no bilge water accumulation in the treatment unit, which reduces the working pressure of the bilge water filter 22 and improves the working life of the bilge water filter 22.

[0049] like Figure 1As shown, when the clean bilge water collection tank 5 contains bilge water, it sends a signal to the control unit 6. The control unit 6 determines the discharge signal 7. When the discharge signal 7 indicates that bilge water can be discharged, the control unit 6 sends a signal to control the clean bilge water discharge pump 10 to pump the bilge water from the clean bilge water collection tank 5 to the second discharge control valve 4. The second discharge control valve 4 senses the bilge water coming from the first discharge control valve 3 and the clean bilge water collection tank 5 and sends a signal to the control unit 6. After determining that the discharge signal 7 indicates that bilge water can be discharged, the control unit 6 opens the second discharge control valve 4, i.e., the multi-stage water treatment discharge system switches to normal discharge mode and / or bilge water collection tank emptying mode. After determining that the discharge signal 7 indicates that bilge water cannot be discharged, the control unit 6 keeps the second discharge control valve 4 closed, i.e., the multi-stage water treatment discharge system switches to restricted discharge mode. When the bilge water collection tank contains bilge water, it sends a signal to the control unit 6 to determine the discharge signal 7 so as to control the clean bilge water collection tank when it can be discharged. The water discharge pump 10 operates to deliver bilge water to the second discharge control valve 4, controlling the amount of bilge water in the clean bilge water collection tank 5 to prevent excessive accumulation. After the second discharge control valve 4 senses bilge water from the first discharge control valve 3 or from the clean bilge water collection tank 5, it sends a signal to the control unit 6. After the control unit judges the discharge signal 7, it opens the second discharge control valve 4 when discharge is possible and closes it when discharge is not possible. This completes the conversion of the multi-stage water treatment discharge system to the restricted discharge mode, the normal discharge mode, and / or the bilge water collection tank emptying mode. The restricted discharge mode and the normal discharge mode conflict, as do the restricted discharge mode and the bilge water collection tank emptying mode. However, the normal discharge mode can exist simultaneously with or independently of the bilge water collection tank emptying mode. This allows for rapid switching of the multi-stage water treatment discharge system's operating mode when discharge and non-discharge conditions change, ensuring the system's stability and efficiency.

[0050] like Figure 1 As shown, there is also a discharge monitoring unit 11 on the pipeline from the second discharge control valve 4 to the outside. The discharge monitoring unit 11 monitors and records the flow rate and oil concentration, and sends the recorded information to the control unit 6. When the oil concentration of the bilge water from the second discharge control valve 4 is too high, the discharge monitoring unit 11 automatically stops discharging to the outside and directs the bilge water to the sewage treatment unit 2, which can further ensure that the bilge water can be discharged. At the same time, the recorded data can be analyzed by maintenance personnel, which is beneficial for targeted maintenance when the system fails.

[0051] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A water treatment and discharge method for a multi-stage water treatment and discharge system, characterized in that, The multi-stage water treatment and discharge system is used for bilge water generated by cruise ships. The multi-stage water treatment and discharge system includes a sewage well suction port, a sewage treatment unit, a first discharge control valve, a second discharge control valve, and a clean bilge water collection tank. The sewage well suction port is connected to the sewage treatment unit, the sewage treatment unit is connected to the first discharge control valve, the first discharge control valve is connected to the second discharge control valve or the clean bilge water collection tank, the clean bilge water collection tank is connected to the second discharge control valve, and the second discharge control valve leads to the outside of the ship; When the multi-stage water treatment and discharge system is in normal discharge mode, the first discharge control valve controls the bilge water from the wastewater treatment unit to flow to the second discharge control valve and outwards; When the multi-stage water treatment and discharge system is in the restricted discharge mode, the first discharge control valve controls the flow of bilge water from the wastewater treatment unit to the clean bilge water collection tank. When the multi-stage water treatment and discharge system changes from the restricted discharge mode to the clean bilge water collection tank emptying mode, the second discharge control valve opens to discharge the bilge water in the clean bilge water collection tank to the outside of the ship. The wastewater treatment unit includes a bilge water pretreatment cabinet and a bilge water oil filter. The bilge water pretreatment cabinet is upstream of the bilge water oil filter. The bilge water pretreatment cabinet and the bilge water oil filter include pipes leading to the waste oil tank. The multi-stage water treatment and discharge system also includes a control unit, which is used to receive discharge signals from the chamber and sewage well level switch signals. The emission signals include a positioning signal and a speed signal. The positioning signal is used to distinguish whether the cabins of the cruise ship are in an area without emission restrictions, and the speed signal is used to distinguish whether the cruise ship is sailing or stationary. The emission signal is permitted when the positioning signal indicates that the cruise ship's cabin is in an area without emission restrictions and the speed signal indicates that the cruise ship is sailing. In this case, the multi-stage water treatment emission system switches to the normal emission mode and the clean bilge water collection tank emptying mode. In other states, the emission signal is not permitted, and the multi-stage water treatment emission system switches to the restricted emission mode.

2. The water treatment and discharge method of the multi-stage water treatment and discharge system according to claim 1, characterized in that, The pipeline between the sewage well suction port and the sewage treatment unit is also equipped with a bilge water collection pump. The inlet of the bilge water collection pump is connected to the sewage well suction port, and the outlet of the bilge water collection pump is connected to the sewage treatment unit. And / or, a clean bilge water discharge pump is also provided on the pipeline between the clean bilge water collection tank and the second discharge control valve, the inlet of the clean bilge water discharge pump is connected to the clean bilge water collection tank, and the outlet of the clean bilge water discharge pump is connected to the second discharge control valve.

3. The water treatment and discharge method of the multi-stage water treatment and discharge system according to claim 1, characterized in that, The first emission control valve and the second emission control valve are three-way control valves.

4. The water treatment and discharge method of the multi-stage water treatment and discharge system according to claim 2, characterized in that, The signal of the sewage well level switch is located at the sewage well where the sewage well suction port is located, and the signal is issued when the liquid level in the sewage well is higher than the sewage well level switch. When the control unit receives a signal from the sewage well level switch, the control unit controls the bilge water collection pump to pump the bilge water in the sewage well to the sewage treatment unit.

5. The water treatment and discharge method of the multi-stage water treatment and discharge system according to claim 4, characterized in that, After treating the bilge water, the wastewater treatment unit sends a treatment signal to the control unit. Upon receiving the treatment signal, the control unit determines the discharge signal. If the discharge is not permitted, the control unit will send a signal to control the first discharge control valve to the clean bilge water collection tank, and the multi-stage water treatment discharge system will switch to the restricted discharge mode. If discharge is permitted, the control unit will send a signal to switch the first discharge control valve to the second discharge control valve, and the multi-stage water treatment discharge system will begin to switch to the normal discharge mode.

6. The water treatment and discharge method of the multi-stage water treatment and discharge system according to claim 5, characterized in that, When the clean bilge water collection tank contains bilge water, it sends a signal to the control unit. The control unit determines the discharge signal. When the discharge signal indicates that the bilge water can be discharged, the control unit sends a signal to control the clean bilge water discharge pump to pump the bilge water from the clean bilge water collection tank to the second discharge control valve. And / or, the second discharge control valve senses the bilge water coming from the first discharge control valve and the clean bilge water collection tank and sends a signal to the control unit; After determining that the emission signal is compliant, the control unit opens the second emission control valve, and the multi-stage water treatment emission system switches to the normal emission mode and / or the bilge water collection tank emptying mode. After determining that the discharge signal is non-dischargeable, the control unit keeps the second discharge control valve closed, and the multi-stage water treatment discharge system switches to the restricted discharge mode.

7. The water treatment and discharge method of the multi-stage water treatment and discharge system according to claim 1, characterized in that, There is also a discharge monitoring unit on the pipeline from the second discharge control valve to the outside. The discharge monitoring unit monitors and records the flow rate and oil concentration, and sends the recorded information to the control unit. When the oil concentration of the bilge water coming from the second discharge control valve is too high, the discharge monitoring unit automatically stops discharging to the outside and directs the bilge water to the sewage treatment unit.

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