CN105130074A - Electro-catalysis /ultraviolet composite ship ballast water treatment method and equipment - Google Patents

Abstract

The invention relates to a ship ballast water treatment method and equipment adopting a joint treatment method, which solves the problems of low efficiency and high power consumption of the existing ship ballast water treatment method and equipment. The method of the present invention is realized through the following steps in turn: a, filtering the ship's ballast water to remove impurities larger than 50 microns; b, generating strong oxidizing free radicals through an electrocatalytic process; c, processing through a light radiation reactor Ship's ballast water. The invention utilizes the electrocatalysis/photocatalysis synergy to kill microorganisms under the joint action of ultraviolet radiation and strong oxidizing free radicals, thereby meeting the requirement of purifying water quality. The ship ballast water treatment equipment of the present invention includes a coarse grid, a water pump, a high-efficiency filter, a No. 1 control valve, an electrocatalytic reactor and a photoradiation reactor.

Description

An electrocatalytic/ultraviolet composite ship ballast water treatment method and equipment

technical field

The invention relates to a treatment method for ship's ballast water, and also relates to a treatment device for ship's ballast water.

Background technique

The problem of off-site discharge of ship ballast water has been listed by the International Maritime Organization (IMO) and international environmental supervision departments as one of the four major hazards to global marine ecological environment security. According to the statistics of the International Maritime Organization, more than 10 billion tons of ballast water are discharged into the ocean every year in the world, and at least 7,000 organisms travel to other places with the ballast water of ships every day. Species invade each other, exacerbating the deterioration of the marine ecological chain and environment. The freight transported by ships accounts for 80% of the world's total freight, and there are more and more ocean-going ships. Therefore, ship ballast water has been regarded as one of the growing scourges that destroy the global marine ecological chain.

The ship's ballast water treatment system is processed while the cargo ship is loading ballast water. How to improve the efficiency of the treatment system on the premise of meeting the ballast water discharge requirements of the International Maritime Organization is the goal of the research and development workers. In recent years, there have been endless treatment methods for ship's ballast water, mainly using displacement, mechanical, physical and chemical methods to treat ship's ballast water. However, studies have found that the credible replacement rate of ballast water is only about 70% to 90%, and the remaining foreign organisms and sediment at the bottom of the ballast tank will be resuspended after replacement, which cannot achieve the purpose of complete replacement; Smaller bacteria and viruses cannot be removed when carrying water; heating is not suitable for hulls that cannot provide enough heat, and maintaining a uniform ballast water temperature is difficult to achieve, and it will also cause damage to the hull's pipes, pumps, and cabin coatings. Adverse effects: The ozone preparation method is complicated, and at the same time it will aggravate the corrosion of the hull and cabin, and the excessively high ozone concentration will also affect the health of the crew.

Ultraviolet radiation technology and electrocatalytic technology have been applied to the treatment of ship ballast water. Shi Jian invented a ship ballast water treatment device (invention patent, patent publication number CN103708582A), which is mainly powered by a high-frequency high-voltage power supply, and a dielectric barrier discharge reaction device processes ship ballast water. The treatment system uses high-voltage high-frequency The power supply has a high risk of use, and at the same time, an excessively high voltage will aggravate the occurrence of electrode side reactions, increase power consumption, and cannot achieve a satisfactory treatment level for the ship's ballast water. Bai Zhenguang invented an efficient ship ballast water treatment system (invention patent, patent publication number CN101948204A), which mainly uses ultraviolet disinfection technology to kill bacteria and viruses in ship ballast water. According to scientific research, the wavelength of ultraviolet radiation is 254nm Sometimes it has a strong damaging effect on the DNA of bacteria and viruses, but it cannot effectively kill algae species in ballast water. It can be seen that the high-frequency voltage and ultraviolet radiation treatment system alone cannot treat the ship's ballast water to the international discharge standard.

UV/electrocatalysis is a composite treatment technology that combines ultraviolet radiation with electrocatalysis technology. Organic matter is treated with ultraviolet radiation immediately after electrocatalytic treatment, and some oxidative substances produced by electrocatalysis, such as OH, can accelerate the reaction with organic substances after ultraviolet radiation. At present, there are few reports on the combined treatment of ballast water by UV/electrocatalysis, and it is mainly used in the research of industrial wastewater and domestic sewage. Zhang Zuyun studied the photoelectric synergy of Bi _x TiO _y -TiO ₂ composite membrane electrode to sterilize simulated ballast water with a bacterial concentration of 10 ⁶ CFU/mL. The results showed that when the applied voltage was 9V and the contact area between the electrode and the solution was 140cm ² , Under the irradiation of 20W ultraviolet germicidal lamp, the reaction for 2 minutes can completely remove the bacteria in the ballast water.

Studies have shown that the combined UV/electrocatalytic technology has synergistic advantages in the treatment of ship ballast water, and has a higher microbial inactivation efficiency than a single treatment system.

Contents of the invention

The object of the present invention is to provide a treatment method for ship ballast water to solve the problems of low efficiency and high cost of the existing ship ballast water treatment method. The method of the present invention is realized through following steps successively: a, adopt high-efficiency filter to filter ship's ballast water, remove the sundry greater than 50 microns; b, by electrocatalytic reactor, electrode produces strong oxidizing free radical Kill; c. Treat the ship's ballast water with a photocatalytic reactor, so as to further remove bacteria, single-celled algae, and protozoa in the ballast water.

The present invention also relates to a ship ballast water treatment device adopting the above treatment method. It consists of: coarse grid 1, water pump 2, high efficiency filter 3, No. 1 control valve 4, electrocatalytic reactor 5, light radiation reactor 6, and the ballast water pipeline of the ship passes through the coarse grid 1 and then connects to the water pump 2 The inlet and the outlet of the water pump 2 are connected to the inlet of the high-efficiency filter 3, the liquid outlet of the high-efficiency filter 3 is connected to one end of the No. 1 control valve 4, and the other end of the No. 1 control valve 4 is connected to the inlet of the electrocatalytic reactor 5, and the electrocatalytic reaction One or more pairs of electrocatalytic electrodes are staggered in the device 5, including an anode 5-1 and a cathode 5-2. The outlet of the electrocatalytic reactor 5 is connected to the inlet of the photoradiation reactor 6 through a flange, and the photoradiation reactor 6 The outlet of the outlet is arranged on the upper end of the reactor 6, and includes one or more quartz tubes 6-2 in the light radiation reactor 6, and each quartz tube 6-2 can run through the reactor 6 in the horizontal direction or in the height direction, and multiple The quartz tubes 6-2 are uniformly distributed in the reactor 6, and an ultraviolet lamp 6-1 is arranged in each quartz tube 6-2.

The ballast water first passes through the coarse grid 1 and the high-efficiency filter 3 to remove impurities and microorganisms longer than 50 μm in the ballast water, and the filtered ballast water enters the electrocatalytic reactor 5, and the high-efficiency electrocatalytic electrode generates strong oxidizing free The base kills the microorganisms in the ballast water and at the same time oxidizes Cl ^- to generate secondary oxidative substances. Finally, the ballast water enters the light radiation reactor 6, and removes bacteria, Monocellular algae, protozoa.

In the electrocatalytic system, the shape-stable anode (DSA) has a high surface energy and a strong affinity when in contact with seawater, which will generate a "surface hydroxyl" process. The metal oxide MO _x coated on the surface of the titanium-based electrode is more attractive to the electrons in the hydroxyl group due to its higher electronegativity, which shortens the MO bond, while elongating the OH bond and weakening its bond energy. The reaction process as follows:

(MO _x )-OH→(MO _x )-O·+H ⁺ +e ^-

(MO _x )-O +OH ^- →(MO _x )-O ^- +HO

(MO _x )-O ^- +H ₂ O→(MO _x )-OH+OH ^-

Based on the above three formulas, it can be considered that water generates OH on the surface of Ti/MO _x . The standard oxidation-reduction potential of OH is as high as 2.80V, _second only to F2's 2.87V, and has higher oxidation ability than other common oxidants, which can destroy the permeability of microbial cell membrane and then destroy its integrity, and even directly destroy microorganisms of DNA leads to the death of microorganisms. In the light radiation reactor, ultraviolet light with a wavelength of 254nm is used to destroy the DNA genetic system of microorganisms, and the continuous oxidation of oxidizing substances in the light radiation reactor is used to achieve the purpose of killing microorganisms in ballast water.

The advantage of the method and equipment of the present invention is that the oxidation of the electrocatalysis system is combined with the synergistic effect of electrocatalysis/light radiation to kill microorganisms with tenacious vitality, and the microorganisms can be killed at a high speed and high efficiency, so as to realize the process of transporting ballast water in pipelines. Directly remove bacteria, single cell algae and protozoa in ballast water.

Description of drawings

Fig. 1 is the flow chart of ship's ballast water treatment method of the present invention;

Fig. 2 is the structural diagram of electrocatalytic reactor of the present invention;

Fig. 3 is a structural diagram of the light radiation reactor of the present invention.

Detailed ways

The sterilizing ability of the equipment in this embodiment will be investigated through experiments, and the effectiveness of the method and equipment will be characterized by the inactivation rate of Escherichia coli.

Embodiment 1: The ballast water treatment equipment includes: a coarse grid 1, a water pump 2, a high-efficiency filter 3, a No. 1 control valve 4, and an electrocatalytic reactor 5. The ship's ballast water pipeline passes through the coarse grid 1 and connects to the inlet of the water pump 2, the outlet of the water pump 2 connects to the inlet of the high-efficiency filter 3, the liquid outlet of the high-efficiency filter 3 connects to one end of the first control valve 4, and the first control valve 4 The other end communicates with the inlet of the electrocatalytic reactor 5, and a plurality of pairs of electrocatalytic electrodes are staggeredly arranged in the electrocatalytic reactor 5.

The treatment method of the ship's ballast water in this embodiment is realized through the following steps in turn: a. Filter the ship's ballast water to remove microorganisms larger than 50 μm; filter to filter out debris. b. Treat the ship's ballast water with an electrocatalytic reactor, thereby removing bacteria, single-celled algae, and protozoa in the ship's ballast water. The effective reaction volume of the electrocatalytic reactor is 0.2L. Two Ti/SnO ₂ anodes and three stainless steel cathodes are used, and the current density is set to 60mA/cm ² . Natural seawater was selected as the experimental sample of simulated ship ballast water. The total number of bacteria was 10 ⁶ CFU/100mL, the number of coliforms was 40 CFU/100mL, and the cultured E. coli was added to make the concentration reach 10 ⁸ CFU/mL. Adjust the flow rate of the water pump so that the hydraulic retention time of the ship's ballast water in the electrocatalytic reactor is 1.5s, 2.5s, and 3.5s, respectively. After the system was running stably, samples were taken, and the inactivation rate of Escherichia coli was determined by the MPN method, as shown in Table 1.

Embodiment 2: The ballast water treatment equipment includes: a coarse grid 1, a water pump 2, a high-efficiency filter 3, a No. 1 control valve 4, an electrocatalytic reactor 5, and a light radiation reactor 6. The ship's ballast water pipeline passes through the coarse grid 1 and connects to the inlet of the water pump 2, the outlet of the water pump 2 connects to the inlet of the high-efficiency filter 3, the liquid outlet of the high-efficiency filter 3 connects to one end of the first control valve 4, and the first control valve 4 The other end of the electrocatalytic reactor 5 is connected to the inlet of the electrocatalytic reactor 5, and a plurality of pairs of electrocatalytic electrodes are staggered in the electrocatalytic reactor 5, and the outlet of the electrocatalytic reactor 5 is connected to the inlet of the photoradiation reactor 6 through a flange. The reactor 6 includes a quartz tube 6-2, the quartz tube 6-2 runs through the reactor 6 in the height direction, and an ultraviolet lamp 6-1 is arranged in the quartz tube 6-2.

The difference between this embodiment and Embodiment 1 is: this embodiment also includes step c after step a and step b, using ultraviolet light to irradiate the ship’s ballast water, the light radiation reactor adopts a low-pressure mercury lamp, and the ultraviolet lamp jacket is covered with Quartz sleeve. The other steps are the same as those in Embodiment 1. After the system runs stably, samples are taken, and the inactivation rate of Escherichia coli is determined by the MPN method, as shown in Table 2.

Specific embodiment three: the ballast water treatment equipment and implementation steps adopted in this embodiment are the same as in embodiment two, the difference is that: natural seawater is selected as the simulated ship ballast water as an experimental sample, and the cultured Dunaliella salina is added to make The concentration of algal cells was 1×10 ⁴ cells/mL, and the current density was set at 100 mA/cm ² . After the system is running stably, samples are taken at the outlet respectively, and samples are taken after being placed in the dark for 2 hours. The CFDA-AM fluorescence staining method was used to quantitatively detect Dunaliella salina, and the inactivation rate of the algae was shown in Table 3.

The above specific implementations are only the principle basic implementations of the present invention, and it should be pointed out that the present invention is not limited by the above examples, and other improvements can be made to the implementations of the present invention, and these improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. a treatment process for ballast water for ship, is characterized in that it is realized by following step successively: a, filter ballast water for ship, removes the foreign material being greater than 50 microns; B, produces strong oxidizing property free radical by catalysis electrode, is mixed in ballast water for ship; C, use UV-irradiation Treatment of Ships'Ballast Water.

2. the treatment process of ballast water for ship according to claim 1, to is characterized in that in step c, with while UV-irradiation ballast water for ship in reactor, can adding in the reactor or not adding TiO ₂photocatalyst.

3. the treatment facility of ballast water for ship, is characterized in that it comprises coarse rack 1, water pump 2, high efficiency filter 3, control valve 4, electric catalysis reactor 5, an optical radiation reactor 6; Coarse rack 1 and water pump 2 are installed in the entrance front end of high efficiency filter 3, one end of the logical control valve 4 of outlet, the other end of a control valve 4 is communicated with the entrance of reactor 5, the outlet of reactor 6 is directly connected by flange with the entrance of reactor 5, the outlet of reactor 6 is arranged on the upper end of reactor 6, and UV-lamp 6-1 is from top to bottom through in reactor 6 inner chamber.

4. the treatment facility of ballast water for ship according to claim 4, it is characterized in that in electric catalysis reactor 5, comprising one or more pairs of staggered electrode, anode 5-1 is the catalysis electrode containing specific coatings, negative electrode 5-2 is noble electrode, and water ballast passes through in the staggered gap of anode and cathode.

5. the treatment facility of ballast water for ship according to claim 4, it is characterized in that in optical radiation reactor 6, comprising one or more silica tube 6-2, each silica tube 6-2 can laterally or in short transverse through reactor 6, multiple silica tube 6-2 is evenly distributed in reactor 6, arranges a UV-lamp 6-1 in each silica tube 6-2.