Ship ballast water treatment device, treatment system and method

Abstract

A ship ballast water treatment device, treatment system and method, the device comprises a photolytic chlorine disinfection treatment chamber and a wavelength 285nm ultraviolet lamp, the photolytic chlorine disinfection treatment chamber has a ballast water input port, a ballast water output port and a hypochlorous acid addition port, the wavelength 285nm ultraviolet lamp is arranged in the photolytic chlorine disinfection treatment chamber, the hypochlorous acid addition port is used to add hypochlorous acid into the photolytic chlorine disinfection treatment chamber, the ship ballast water flows into the photolytic chlorine disinfection treatment chamber through the ballast input port, hypochlorous acid enters the photolytic chlorine disinfection treatment chamber through the hypochlorous acid addition port, and is irradiated by the wavelength 285nm ultraviolet lamp in the photolytic chlorine disinfection treatment chamber to perform photolytic chlorine disinfection. The application of the present invention can reduce the demand for high ultraviolet radiation dose and high oxidant concentration of the ballast water treatment system, reduce the energy consumption and environmental risks of the prior art, and improve the efficiency and reliability of ballast water treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a ship ballast water treatment device, a treatment system and a method. Background Art

[0002] For centuries, the introduction of non-native organisms has been growing exponentially around the world. Species invasions threaten biodiversity, accelerate homogenization, and have negative impacts on marine industries and human health. The most important route for the spread of aquatic invasive species is ship ballast water. Invasive algae, shellfish, and bacteria discharged through ballast water have become one of the most serious problems in today's oceans. The United States Coast Guard (USCG) and the International Maritime Organization (IMO) implemented the USCG ETV standard and the International Convention for the Control and Management of Ships' Ballast Water and Sediments (hereinafter referred to as the Ballast Water Convention) in 2012 and 2016, respectively. Both regulations stipulate the concentration of microorganisms in discharged ballast water: (1) Microorganisms larger than 50 um are less than 10 / m 3 ; (2) Microorganisms larger than 10um and smaller than 50um are less than 10 / ml; (3) Three indicator microorganisms, toxigenic cholerae (less than 1 cfu per 100 ml), Escherichia coli (less than 250 cfu per 100 ml) and enterococci (less than 100 cfu per 100 ml). After October 28, 2018, new ships entering the ports of contracting states must be equipped with a ballast water treatment system that has passed strict certification. The ballast water treatment system has entered an era of high standards and strict requirements. Therefore, it is necessary to develop economical and efficient ballast water treatment technology to ensure the safety and efficiency of ballast water discharge.

[0003] Since the ballast water system approval procedure was passed, as of October 2019, 22 ballast water treatment systems have passed USCG type certification worldwide. Most of the certified ballast water treatment devices include two processes: (1) filtration / mechanical separation process, which is mainly used to separate larger particle impurities and organisms in ballast water; (2) disinfection and inactivation process, which uses ultraviolet disinfection and oxidation technology as the main process and is the main unit of the ballast water system. In addition to the above engineering application technologies, some literatures have also proposed schemes for coupling multiple technologies for ballast water disinfection. Scholars proposed to use ultraviolet and nano-titanium dioxide catalysts for ballast water disinfection. The hydroxyl radicals produced by this scheme have strong oxidizing properties and rapid inactivation, but the loss and disposal of catalysts limit its engineering application. Other scholars have proposed a disinfection scheme combining ultraviolet, ultrasound and ozone technology. However, this scheme requires a large space and operating cost. Ultrasound may also pose a threat to humans and the hull. The byproducts produced by disinfection are harmful to the environment. Engineering applications need to be evaluated.

[0004] The current ballast water installations use ultraviolet disinfection or oxidation technology as the main process, both of which have different disadvantages or technical problems.

[0005] The ultraviolet disinfection process uses traditional ultraviolet mercury lamps. The following problems exist in the use of this technology for disinfection: ① It is more effective against microorganisms such as bacteria, but killing ultraviolet-resistant microorganisms such as phytoplankton and zooplankton in ballast water requires increasing the ultraviolet intensity or irradiation dose, which consumes a lot of energy; ② Ultraviolet mercury lamps have a short lifespan, contain toxic mercury, are fragile, require preheating, and are too large, which limits their application on ships where space is precious and maintenance costs are high.

[0006] The current oxidation technology uses electrolysis to produce hypochlorous acid or chlorine dioxide. The disadvantages of this technology are: ① It is costly to produce high concentrations of oxidants in low-salinity seawater; ② Usually an oxidant concentration higher than 10 mg / L is required to completely kill microorganisms, but at the same time, the large amount of disinfection by-products produced by disinfection also poses a high risk to the aquatic environment.

[0007] It can be seen that the existing treatment systems and technologies have the characteristics of high construction and maintenance costs, high environmental risks and low reliability. It is necessary to develop economical, efficient and stable ballast water treatment technologies and systems. Summary of the invention

[0008] The main purpose of the present invention is to remedy the defects of the prior art and provide a ship ballast water treatment device, a treatment system and a method to reduce the demand for high ultraviolet radiation dose and high oxidant concentration of the ballast water treatment system, reduce the energy consumption and environmental risks of the prior art, and improve the efficiency and reliability of ballast water treatment.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A ship ballast water treatment device comprises a photolytic chlorine disinfection treatment chamber and a wavelength 285nm ultraviolet lamp, wherein the photolytic chlorine disinfection treatment chamber has a ballast water input port, a ballast water output port and a hypochlorous acid addition port, the wavelength 285nm ultraviolet lamp is arranged in the photolytic chlorine disinfection treatment chamber, the hypochlorous acid addition port is used to add hypochlorous acid into the photolytic chlorine disinfection treatment chamber, the ship ballast water flows into the photolytic chlorine disinfection treatment chamber through the ballast input port, hypochlorous acid enters the photolytic chlorine disinfection treatment chamber through the hypochlorous acid addition port, and is irradiated by the wavelength 285nm ultraviolet lamp in the photolytic chlorine disinfection treatment chamber to perform photolytic chlorine disinfection.

[0011] Further:

[0012] It also includes a hypochlorous acid generator, which is connected to the hypochlorous acid adding port.

[0013] The ultraviolet lamp with a wavelength of 285nm is an ultraviolet LED.

[0014] The 285nm wavelength ultraviolet lamp includes a plurality of LED light source panels.

[0015] The multiple LED light source panels include a first row of light source panels and a second row of light source panels. The first row of light source panels are vertically fixed on a first inner wall of the photolytic chlorine disinfection treatment chamber between the ballast water inlet and the ballast water outlet. The second row of light source panels are vertically fixed on a second inner wall of the photolytic chlorine disinfection treatment chamber between the ballast water inlet and the ballast water outlet. The first row of light source panels and the second row of light source panels are alternately arranged to form a ballast water channel with multiple twists and turns in the photolytic chlorine disinfection treatment chamber.

[0016] The first inner wall and the second inner wall are two opposite inner side walls.

[0017] A ship ballast water treatment system comprises the ship ballast water treatment device and a ballast water pipeline connected to the ship ballast water treatment device.

[0018] A ship ballast water treatment method uses the ship ballast water treatment device to perform photolysis chlorine disinfection on the ship ballast water.

[0019] Further:

[0020] The chlorine concentration formed by adding sodium hypochlorite is ≥0.6 mg / L, or the chlorine concentration formed by adding sodium hypochlorite is ≥0.8 mg / L.

[0021] 0.6mg / L chlorine concentration with 200mJ / cm 2 UV dose, or 0.8mg / L chlorine concentration with 100mJ / cm 2 of UV dose.

[0022] The present invention has the following beneficial effects:

[0023] The present invention proposes a ship ballast water treatment device, a treatment system and a method, which use an ultraviolet lamp with a wavelength of 285nm in combination with a photochlorination disinfection treatment chamber to add sodium hypochlorite to perform photochlorination disinfection of ship ballast water, and have both the best inactivation effect and the lowest inactivation energy consumption, and can significantly reduce the requirements of the ballast water treatment system for high ultraviolet radiation dose and high oxidant concentration, reduce the energy consumption and environmental risks of the prior art, and improve the efficiency and reliability of ballast water treatment.

[0024] Applying the ultraviolet lamp irradiation-photolysis chlorine combined disinfection technology solution of the present invention to the marine environment can improve the problems of high maintenance cost, high energy consumption, low reliability and high environmental risk of existing ballast water disinfection technology.

[0025] Compared with the conventional technology, the ship ballast water treatment device based on the photolysis of low-dose chlorine by ultraviolet LED with a wavelength of 285nm proposed in the embodiment of the present invention has the following advantages:

[0026] ① Greatly reduce the system's demand for ultraviolet radiation dose and improve the overall disinfection efficiency;

[0027] ② Low processing energy consumption, which is at least 12 times lower than that of UV LED disinfection at the same disinfection efficiency;

[0028] ③ Low environmental risk, low concentration of chlorine can completely kill microorganisms, avoiding the production of high concentration of disinfection by-products;

[0029] ④The wavelength of UV LED is selective, so it can match the UV light with a wavelength of 285nm, greatly improving the disinfection effect;

[0030] ⑤ Compared with traditional mercury lamps, LED light sources are mercury-free, green and safe, sturdy and compact, occupy a small space, do not require preheating, have a long life, and have low subsequent operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a top view of a sectional schematic diagram of a ship ballast water treatment device according to an embodiment of the present invention.

[0032] Figure 2 This is a three-dimensional perspective structural diagram of a ship ballast water treatment device according to an embodiment of the present invention.

[0033] Figure 3 The present invention is a schematic structural diagram of a ship ballast water treatment system according to an embodiment of the present invention.

[0034] Figure 4 This is a graph showing the inactivation rate of Cardella by UV LED-photolysis chlorine (0.6 mg / L) disinfection devices with different wavelengths;

[0035] Figure 5 This is a comparison chart of the energy consumption for inactivation of Cardella by UV LED-photolysis of chlorine at different wavelengths with a 2-log reduction;

[0036] Figure 6 This is a comparison chart of the effect of 285nm UV LED-photolysis chlorine inactivation of Cardella under different chlorine addition amounts and different dosages;

[0037] Figure 7 This is a comparison chart of the residual chlorine concentration of water samples after the Cardinalis was inactivated by photolysis of chlorine (0.6 mg / L) at five different wavelengths. DETAILED DESCRIPTION

[0038] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0039] See also Figure 1 and Figure 2 The embodiment of the present invention provides a ship ballast water treatment device 1, comprising a photolytic chlorine disinfection treatment chamber 15 and a 285nm wavelength ultraviolet lamp 14. The photolytic chlorine disinfection treatment chamber 15 has a ballast water input port 11, a ballast water output port 12 and a hypochlorous acid addition port 13, and the 285nm wavelength ultraviolet lamp 14 is arranged in the photolytic chlorine disinfection treatment chamber 15. The photolytic chlorine disinfection treatment chamber 15 is arranged on the ballast or discharge path of the ship ballast water to be treated, and the ballast water input port 11 and the ballast water output port 12 are connected to the corresponding ballast water pipeline 31. The hypochlorous acid addition port 13 is used to add hypochlorous acid into the photolytic chlorine disinfection treatment chamber 15. During operation, the ship's ballast water flows into the photolytic chlorine disinfection treatment chamber 15 through the ballast input port 11, and hypochlorous acid enters the photolytic chlorine disinfection treatment chamber 15 through the hypochlorous acid addition port 13, and is irradiated by the 285nm wavelength ultraviolet lamp 14 in the photolytic chlorine disinfection treatment chamber 15, and then output from the ballast water output port 12 after photolytic chlorine disinfection.

[0040] The ship ballast water treatment device 1 of the embodiment of the present invention uses an ultraviolet lamp 14 with a wavelength of 285nm to perform photolysis chlorine disinfection of ship ballast water, which has both the best inactivation effect and the lowest inactivation energy consumption, and can significantly reduce the ballast water treatment system's requirements for high ultraviolet radiation doses and high oxidant concentrations, reduce the energy consumption and environmental risks of the prior art, and improve the efficiency and reliability of ballast water treatment.

[0041] In a preferred embodiment, the ship ballast water treatment device 1 further includes a hypochlorous acid generator (not shown), and the hypochlorous acid generator is connected to the hypochlorous acid addition port 13 .

[0042] In a preferred embodiment, the 285nm wavelength ultraviolet lamp 14 is an ultraviolet LED.

[0043] like Figure 1 and Figure 2 As shown, in a more preferred embodiment, the 285nm wavelength ultraviolet lamp 14 includes a plurality of LED light source panels.

[0044] like Figure 1 and Figure 2As shown, in a further preferred embodiment, the multiple LED light source panels include a first row of light source panels and a second row of light source panels, the first row of light source panels are vertically fixed on the first inner wall of the photolytic chlorine disinfection treatment chamber 15 between the ballast water inlet 11 and the ballast water outlet 12, the second row of light source panels are vertically fixed on the second inner wall of the photolytic chlorine disinfection treatment chamber 15 between the ballast water inlet 11 and the ballast water outlet 12, the first row of light source panels and the second row of light source panels are alternately arranged to form a ballast water channel with multiple twists and turns in the photolytic chlorine disinfection treatment chamber 15.

[0045] exist Figure 1 and Figure 2 In the preferred embodiment shown, the first inner wall and the second inner wall to which the first row of light source panels and the second row of light source panels are fixed are two opposite inner side walls. In other embodiments, the first inner wall and the second inner wall may not be opposite inner side walls, for example, they may be upper and lower walls or two adjacent walls, and the first row of light source panels and the second row of light source panels may also be arranged alternately and staggered to form a zigzag channel.

[0046] The ultraviolet lamp 14 with a wavelength of 285 nm in the present invention is preferably an ultraviolet LED. In other embodiments, the ultraviolet lamp 14 may also be a traditional ultraviolet mercury lamp as long as the wavelength is 285 nm.

[0047] See also Figure 3 An embodiment of the present invention further provides a ship ballast water treatment system 3, comprising the ship ballast water treatment device 1 described in any of the aforementioned embodiments and a ballast water pipeline 31 connected to the ship ballast water treatment device 1.

[0048] An embodiment of the present invention further provides a method for treating ship ballast water, using the ship ballast water treatment device 1 described in any of the aforementioned embodiments to perform photo-chlorine disinfection on the ship ballast water.

[0049] In a preferred embodiment, the chlorine concentration formed by adding sodium hypochlorite is ≥0.6 mg / L, or the chlorine concentration formed by adding sodium hypochlorite is ≥0.8 mg / L.

[0050] In a further preferred embodiment, a chlorine concentration of 0.6 mg / L is combined with 200 mJ / cm 2 UV dose, or 0.8mg / L chlorine concentration with 100mJ / cm 2 of UV dose.

[0051] The following is a further description of the principles and advantages of photochlorination disinfection using a ship ballast water treatment device according to a specific embodiment of the present invention.

[0052] In photolysis chlorine disinfection, ultraviolet wavelength and chlorine concentration are significant factors affecting disinfection efficiency. The present invention selects 285nm wavelength ultraviolet lamps to achieve high inactivation efficiency and low energy consumption of ship ballast water disinfection with low-dose chlorine concentration.

[0053] The inventor has found through a large number of research experiments that for ultraviolet wavelengths, ultraviolet rays of 255-265nm are close to the absorption peak range of nucleic acid substances in microbial cells and are most likely to kill microorganisms, but their photoelectric conversion efficiency and chlorine photolysis rate are low, and a high inactivation rate cannot be achieved; ultraviolet rays of 280-285nm wavelength have a high overlap with the maximum absorption peak of hypochlorite, making it easy to match the ultraviolet emission spectrum with the absorption or quantum yield maximum of free chlorine, and can have the advantages of high photoelectric conversion efficiency and high chlorine photolysis rate, and the inactivation rate is high; 300-310nm ultraviolet rays-photolysis chlorine, although it also has a high inactivation rate, the inactivated microorganisms are easy to revive, and there is still a risk of biological invasion when discharged into the environment again. The embodiment of the present invention selects an ultraviolet lamp with a specific wavelength of 285nm as the light source of the photolysis chlorine disinfection device, achieving both economy and efficiency.

[0054] The chlorine used in the embodiment of the present invention is sodium hypochlorite. In the alkaline environment of seawater, sodium hypochlorite mostly exists in the form of hypochlorite, and ultraviolet light decomposes hypochlorite to produce strong oxidizing substances such as hydroxyl radicals and chlorine radicals to inactivate microorganisms. Different from traditional electrolytic chlorine disinfection, the photolytic chlorine disinfection method of the present invention only requires 0.6-0.8 mg / L to achieve the inactivation effect, and no neutralization is required during discharge, which is green and efficient.

[0055] Through experiments, the indicator organism Cardella (concentration of 6*10 4 cells / mL), verifying the principle, advantages and feasibility of the present invention.

[0056] 1) Screening for the best UV LED wavelength for inactivation and lowest energy consumption

[0057] The use of UV LEDs with wavelengths of 265, 280, 285nm, 300nm and 310nm has an algae load of 6*10 4 The water samples with 1.5 cells / mL were inactivated, and the average radiation intensity received by the water samples was 1.5 mW / cm 2 . Figure 4 The inactivation rates of Cardella by UV LED-photolysis chlorine (0.6 mg / L) disinfection devices with different wavelengths were given; Figure 5 A comparison of the inactivation energy consumption of Cardella with different wavelengths of ultraviolet LED-photolysis chlorine for every 2 log reduction is given.

[0058] See also Figure 4From the perspective of inactivation effect, UV LED-photolysis chlorine technology does not require the addition of high concentrations of oxidants, and a chlorine concentration of 0.6 mg / L can meet the requirements of IMO and USCG for the concentration of microorganisms in discharged ballast water. Among them, the 285nm UV LED-photolysis chlorine inactivation requires the lowest UV dose, 150mJ / cm2, which can meet the ballast water discharge requirements.

[0059] See also Figure 5 In terms of inactivation energy consumption, the UV LED-photolytic chlorine combined technology reduces the inactivation energy consumption by at least 12 times compared with the single UV LED technology. Among them, the 285nm UV LED-photolytic chlorine achieved the best inactivation energy consumption.

[0060] Therefore, the present invention adopts ultraviolet LED with a wavelength of 285nm to carry out photolysis chlorine disinfection of ship ballast water, which has both the best inactivation effect and the lowest inactivation energy consumption.

[0061] 2) Screening the most suitable chlorine concentration range in UV LED-chlorine combined technology

[0062] In practical applications, chlorine concentration and UV dose are the main factors affecting the disinfection effect of ship ballast water. Figure 6 The results show that the effect of 285nm UV LED-photolysis of chlorine inactivation of Cardella at different chlorine dosages and doses is given. Figure 6 As can be seen, a chlorine concentration of 0.6 mg / L combined with 200 mJ / cm 2 UV dose; 0.8mg / L chlorine concentration with 100mJ / cm 2 The UV dosage can meet the requirements of IMO and USCG for the concentration of microorganisms in discharged ballast water. Figure 7 The residual chlorine concentration of water samples after inactivation of Cardella by photolysis of chlorine (0.6 mg / L) at five wavelengths is given. It can be seen that the UV dose is greater than 100 mJ / cm 2 When the residual chlorine concentration in the treated water sample meets the IMO requirement that the residual chlorine concentration of the treated ballast water must be lower than 0.2 mg / L, the treated ballast water does not need to consider neutralizing the residual chlorine and can meet the standard for direct discharge. Therefore, the present invention selects a concentration range of greater than or equal to 0.8 mg / L as the chlorine concentration range for the UV LED-photochlorination technology.

[0063] The use of 285nm wavelength ultraviolet LED and low-concentration chlorine to photolyze chlorine disinfection of ship ballast water not only reduces treatment costs, but also has the advantage of low marine environmental risks.

[0064] Applying the 285nm wavelength ultraviolet-photolytic chlorine combined disinfection technology solution to the marine environment can improve the problems of high maintenance cost, high energy consumption, low reliability and high environmental risk of existing ballast water disinfection technology.

[0065] The background section of the present invention may contain background information about the problem or environment of the present invention, but does not necessarily describe the prior art. Therefore, the content included in the background section is not an admission by the applicant that the prior art is available.

[0066] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope defined by this patent application.

Claims

1. A method for treating ship ballast water, using a ship ballast water treatment device to photolyze and inactivate Cardella in ship ballast water, characterized in that: The ship ballast water treatment device comprises a photochlorination disinfection chamber and a wavelength 285nm ultraviolet LED, the photochlorination disinfection chamber has a ballast water input port, a ballast water output port and a hypochlorous acid injection port, the wavelength 285nm ultraviolet LED is arranged in the photochlorination disinfection chamber, the hypochlorous acid injection port is used to inject hypochlorous acid into the photochlorination disinfection chamber, the ship ballast water flows into the photochlorination disinfection chamber through the ballast water input port, and hypochlorous acid enters the photochlorination disinfection chamber through the hypochlorous acid injection port, and the method comprises: the chlorine concentration formed in the ship ballast water is 0.6mg / L, and the 285nm ultraviolet LED in the photochlorination disinfection chamber injects hypochlorous acid at a dose of 200mJ / cm 2 Radiation is used to inactivate the Cardella in the ship's ballast water by photolysis of chlorine, wherein the photolysis of hypochlorite produces strong oxidizing substances to inactivate the Cardella, achieving a combined disinfection of 285nm ultraviolet irradiation-photolysis of chlorine.

2. The ship ballast water treatment method according to claim 1, characterized in that: It also includes a hypochlorous acid generator, which is connected to the hypochlorous acid adding port.

3. The ship ballast water treatment method according to claim 1 or 2, characterized in that: The 285nm wavelength ultraviolet LED includes a plurality of LED light source panels.

4. The ship ballast water treatment method according to claim 3, characterized in that: The multiple LED light source panels include a first row of light source panels and a second row of light source panels. The first row of light source panels are vertically fixed on the first inner wall between the ballast water inlet and the ballast water outlet of the photolytic chlorine disinfection treatment chamber, and the second row of light source panels are vertically fixed on the second inner wall between the ballast water inlet and the ballast water outlet of the photolytic chlorine disinfection treatment chamber. The first row of light source panels and the second row of light source panels are alternately arranged to form a ballast water channel with multiple twists and turns in the photolytic chlorine disinfection treatment chamber.

5. The ship ballast water treatment method according to claim 4, characterized in that: The first inner wall and the second inner wall are two opposite inner side walls.

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