CN108585283B - Hydroxyl radicals kill bloom microalgae and mineralized organic pollutants treatment system and method - Google Patents

Abstract

Hydroxyl free radicals kill bloom microalgae and mineralized organic pollutants treatment system and method thereof, and are provided with a hydroxyl radical strong oxidation pretreatment system, a hydroxyl radical mineralization organic pollutant system, a sodium hypochlorite disinfection unit, a central control system, Residual chlorine online monitor, coagulation sedimentation tank, sand filter, clear water tank, sodium hypochlorite storage tank, mechanical pump, controller, water flow meter, solenoid valve and unit water outlet valve; hydroxyl radical strong oxidation pretreatment system is equipped with hydroxyl radicals The radical strong oxidation pretreatment device, the first water jet cavitation liquid-liquid dissolving device and the first residual chlorine online monitor; the hydroxyl radical mineralization organic pollutant system includes the hydroxyl radical mineralization organic pollutant device, the second water Jet cavitation liquid-liquid dissolving device, the second residual chlorine online monitor.

Description

Hydroxyl free radicals kill bloom microalgae and mineralized organic pollutants treatment system and its method

technical field

The invention relates to the treatment of blooming microalgae and organic pollutants, in particular to a treatment system and method for killing the blooming microalgae and mineralizing organic pollutants by hydroxyl radicals.

Background technique

Lake water or river and reservoir area water is an important source of surface water drinking water in my country. With the development of economy, the nutrient load of surface water drinking water source is increasing, and the main pollution indicators in the water body are chemical oxygen demand, total phosphorus and ammonia nitrogen. The increase in algal blooms in spring and summer led to the blooming of algae. In recent years, my country's Dianchi Lake, Chaohu Lake, Taihu Lake and other large freshwater lakes are basically in a state of eutrophication. A large number of algal blooms broke out in the lake, and the water body was unusually smelly and dark brown. The death of algae further deteriorated the water quality and released a large number of organic pollutants such as algal toxins, which seriously threatened the safety of urban drinking water supply.

At this stage, most of the water plants in my country adopt the water purification process of coagulation-precipitation-filtration-chlorine disinfection. However, when the algal bloom is long, the algal cells may secrete soluble organic matter into the extracellular space. Such substances secreted by algae are mainly composed of nitrogen-containing substances and pentose gums. During the coagulation and sedimentation stage, the complexes formed with iron salts and aluminum salts in the coagulant will be suspended in water, which is not conducive to destabilization. Algae cannot be effectively precipitated. After the coagulation sedimentation tank, the algae in the water can still reach about 10 ⁵ cells/mL, and the high-density algae then enter the filter tank, which is easy to cause blockage of the filter tank. It can be seen that the traditional "coagulation-precipitation-filtration-chlorine disinfection" method cannot kill and remove algae well. In addition, the chemical structures of algal toxins and secondary metabolites such as olfactory substances produced by algae are relatively stable, and it is difficult for them to be oxidatively degraded by conventional chlorine disinfection processes. Li Xueyan, et al. (Li Xueyan, Ma Jun, Chen Zhonglin, et al. Oxidative removal of odorant 2-MIB in water by several oxidants [J]. Journal of Natural Sciences of Heilongjiang University, 2007, 24(01): 76-80) found that KMnO ₄ Disinfectants such as , H ₂ O ₂ and NaClO are almost unable to oxidatively degrade 2-methyl isocamphenol.

Related patents for high algae drinking water in my country have been reported as follows.

Chinese patent CN106044875A discloses a treatment method and treatment system for high algae water. The method of adding different filter materials is used to filter out high algae, but this method requires frequent replacement of membranes, and the cost is high. Chinese patent CN104176839A discloses a treatment system using membrane treatment and powdered activated carbon dosing, but the membrane used needs chemical cleaning, and the powdered activated carbon added may also aggravate membrane pollution by adsorbing on the surface of the membrane. Chinese patent CN104925920A discloses a method for strengthening algal killing by physicochemical, adding copper salt and chlorine at the same time before pretreatment, chlorine free radicals can destroy the integrity of the algal cell wall, and copper ions act on the cytoplasm. However, damage to the algal cell wall may result in the overflow of solutes in the algae, releasing algal toxins. Chinese patent CN101948153A discloses an ultrasonic-ultraviolet coupling pretreatment device for raw water with high algae water, but the processing capacity of this method is only 3m ³ /h, which is difficult to realize the application of water plants.

Comprehensive analysis of the above high algae water treatment technologies shows that although the physical method will not cause the algal cells to rupture and release intracellular solutes, the filter membrane needs to be replaced frequently, and the cost is high. Although traditional chemical methods can effectively kill algae, it is easy to cause secondary pollution and generate toxic disinfection by-products. The hydroxyl radicals generated by advanced oxidation technologies such as ultraviolet method can quickly kill algae and mineralized organic pollutants, but most of the advanced oxidation technologies have small water treatment capacity and cannot achieve large-scale application in water plants. Therefore, it is of great significance to maintain social stability to develop emergency water supply technology and equipment to safely and effectively kill high algae and mineralized organic pollutants and ensure the living water of the masses.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide hydroxyl radicals to kill bloom microalgae and mineralized organic pollutants treatment system and method thereof.

The invention is provided with a hydroxyl radical strong oxidation pretreatment system, a hydroxyl radical mineralization organic pollutant system, a sodium hypochlorite disinfection unit, a central control system, a residual chlorine online monitor, a coagulation sedimentation tank, a sand filter tank, a clear water tank, and sodium hypochlorite. Storage tanks, mechanical pumps, controllers, water flow meters, solenoid valves and unit water outlet valves;

The hydroxyl radical strong oxidation pretreatment system is provided with a hydroxyl radical strong oxidation pretreatment device, a first water jet cavitation liquid-liquid dissolving device and a first residual chlorine online monitor;

The hydroxyl radical mineralization organic pollutant system includes a hydroxyl radical mineralization organic pollutant device, a second water jet cavitation liquid-liquid dissolving device, and a second residual chlorine online monitor;

The hydroxyl radical strong oxidation pretreatment device and the mineralized organic pollutant technical equipment are provided with an atmospheric pressure strong ionization discharge oxygen plasma integrated source, a partition excitation type high-frequency high-voltage power supply, a venturi gas-liquid mixer, a booster pump, Decompression buffers, bag filters and cooling water circulation equipment;

The first water jet cavitation liquid dissolving device and the second water jet cavitation liquid dissolving device are provided with 5 venturi jets connected in parallel, the first water jet cavitation liquid dissolving device and the second water jet cavitation liquid dissolving device. The main water inlet of the cavitation liquid dissolving device is connected to the main water supply pipeline, and the side water inlets of the first water jet cavitation liquid dissolving device and the second water jet cavitation liquid dissolving device are connected to the water outlet of the high-concentration hydroxyl radical generating equipment , choose to open 1 to 5 venturi jets to process 300 to 500 m ³ /h of high-algae water, which is used for high-concentration hydroxyl radical solution and high-efficiency liquid-liquid miscibility of the treated water;

The sodium hypochlorite disinfection unit is provided with a sodium hypochlorite storage tank, the fifth residual chlorine online monitor, the ninth solenoid valve, the seventh mechanical pump, the fourth controller and the third flow meter; the sodium hypochlorite disinfection unit can realize the automatic dosing of sodium hypochlorite solution , Inactivate bacteria, viruses and protozoa in water, control the regrowth of microorganisms in the process of water distribution and inhibit the growth of pipe wall biofilms.

The central control system automatically adjusts the concentration and injection amount of oxygen active particles generated in the plasma integrated source according to the detection results returned by the residual chlorine online monitor, such as algae concentration, chemical oxygen demand COD, pH, turbidity and other parameters, The automatic control of the concentration of hydroxyl radical solution in the high-concentration hydroxyl radical generating equipment is realized. In addition, the central control system can control the opening and closing of the solenoid valve in the system, control the opening and closing of the mechanical pump, and the opening and closing of the sodium hypochlorite disinfection unit through the controller, realizing automatic control during the operation of the entire treatment equipment.

The water source water to be treated is connected to the water inlet of the first mechanical pump in the main treatment pipeline, a first solenoid valve is arranged between the source water to be treated and the first mechanical pump, and the water outlet of the first mechanical pump is connected to the first water flow rate Including the water inlet, the water outlet of the first water flow meter is connected to the water inlet of the first residual chlorine online monitor, and the water outlet of the first residual chlorine online monitor is divided into two channels, one is connected to the water inlet of the second mechanical pump, and the second mechanical pump There is a first controller, a second solenoid valve and a first unit water outlet valve are arranged between the first residual chlorine online monitor and the second mechanical pump, and the water outlet of the second mechanical pump is connected to the hydroxyl radical strong oxidation pretreatment system The main water inlet of the first water jet cavitation liquid dissolving device, and the water outlet of the first water jet cavitation liquid dissolving device is connected to the water inlet of the second residual chlorine online monitor.

The water outlet of the second residual chlorine online monitor is connected to the water inlet of the coagulation and sedimentation tank; the other outlet of the first residual chlorine online monitor is directly connected to the water inlet of the coagulation and sedimentation tank, and the water outlet of the first residual chlorine online monitor is connected to the water inlet of the coagulation and sedimentation tank. A third solenoid valve is arranged between the water inlets of the coagulation sedimentation tank, and a second unit water outlet valve is arranged between the water outlet of the hydroxyl radical strong oxidation pretreatment system and the water inlet of the coagulation sedimentation tank.

The water outlet of the coagulation sedimentation tank is connected to the water inlet of the third mechanical pump, and a fourth solenoid valve is arranged between the water outlet of the coagulation sedimentation tank and the water inlet of the third mechanical pump. The water outlet of the third mechanical pump is connected to the water inlet of the sand filter tank, the water outlet of the sand filter tank is connected to the water inlet of the fifth mechanical pump, the water outlet of the fifth mechanical pump is connected to the water inlet of the third residual chlorine online monitor, and the water outlet of the fifth mechanical pump There is a third unit water outlet valve between the water outlet and the third residual chlorine online monitor. The water outlet of the third residual chlorine online monitor is divided into two channels, one is connected to the water inlet of the fourth mechanical pump, and the fourth mechanical pump water outlet is connected to the first water jet cavitation liquid dissolution in the hydroxyl radical mineralization organic pollutant system The main water inlet of the device, the water outlet of the first water jet cavitation liquid dissolving device is connected to the water inlet of the fourth residual chlorine online monitor, and the water outlet of the fourth residual chlorine online monitor is connected to the main water treatment pipeline; the third residual chlorine The other outlet of the online monitor is directly connected to the clean water tank through the main water treatment pipeline. There is a sixth solenoid valve between the water outlet of the third residual chlorine online monitor and the water inlet of the clean water pool, and the fourth unit water outlet valve is installed between the water outlet of the hydroxyl radical mineralization organic pollutant system and the water inlet of the clean water pool .

A sodium hypochlorite disinfection unit is arranged between the water outlet of the hydroxyl radical mineralization organic pollutant system and the water inlet of the clear water pool, and the water outlet of the sodium hypochlorite storage tank is connected to the water inlet of the fifth residual chlorine online monitor, and the fifth residual chlorine online monitor A ninth solenoid valve, a seventh mechanical pump and a third water flow meter are arranged in sequence between the water outlet and the main water treatment pipeline, and the central control system controls the opening of the seventh mechanical pump through the fourth controller.

The main water treatment pipeline between the water outlet of the sand filter tank and the water inlet of the clear water tank is divided into a branch water treatment pipeline for preparing high-concentration hydroxyl radical solution, and the water treatment branch pipeline is connected to the water inlet of the second water flow meter , the water outlet of the second water flow meter is connected to the water inlet of the sixth mechanical pump, and the water outlet of the sixth mechanical pump of the branch pipeline is divided into two channels, one of which is connected to the hydroxyl radical strong oxidation pretreatment system in the hydroxyl radical strong oxidation pretreatment system The water inlet of the device, the water outlet of the hydroxyl radical strong oxidation pretreatment device is connected to the branch inlet of the first water jet cavitation liquid dissolving device; the other way of the water outlet of the sixth mechanical pump of the branch pipeline is connected to the hydroxyl radical mineralization organic The water inlet of the hydroxyl radical mineralizing organic pollutant device in the pollutant equipment, and the water outlet of the hydroxyl radical mineralizing organic pollutant device is connected to the branch inlet of the first water jet cavitation liquid-liquid dissolving device.

The water outlet of the clean water pool is connected to the water inlet of the 8th mechanical pump, the water outlet of the clean water pool and the water inlet of the 8th mechanical pump are provided with the 5th unit water outlet valve and the 10th solenoid valve, and the water outlet of the 8th mechanical pump is connected to the pipe network .

The method for efficiently killing algal blooms and mineralized organic pollutants by hydroxyl radicals comprises the following steps:

1) Open the first solenoid valve and the first mechanical pump of the main pipeline, inhale the water source water to be treated, and control the water flow through the first water flow meter. system. When it is detected that the density of algae is higher than 1000cells/mL, the hydroxyl radical strong oxidation pretreatment system is activated, and the central control system determines the dose of hydroxyl radical solution to be added according to parameters such as algae concentration, COD, and water turbidity, and sends the signal To the hydroxyl radical strong oxidation pretreatment device, when the density of algae is detected to be lower than 1000cells/mL, the hydroxyl radical strong oxidation pretreatment system is not turned on, the second solenoid valve is closed, the third solenoid valve is opened, and the water source water is directly pumped into the coagulation sedimentation tank, and the water flow in the main pipeline is 300-500 m ³ /h;

2) Hydroxyl radical strong oxidation pretreatment equipment The efficient preparation of hydroxyl radical solution includes the following steps: 1. Turn on the oxygen active group gas generating equipment in the hydroxyl radical strong oxidation pretreatment equipment, and pass the oxygen in the oxygen cylinder into the plasma The generator module activates the high-frequency high-voltage power supply corresponding to the plasma module, and forms an atmospheric pressure ionization discharge in the gap between the extremely narrow discharges, ionizing and dissociating oxygen to generate high-concentration oxygen-active group gas, the amount of which is determined by the activated plasma. 2. Turn on the sixth mechanical pump of the branch pipe and the seventh solenoid valve corresponding to the water flow path of the branch pipe of the hydroxyl radical strong oxidation pretreatment system, control the water flow of the branch pipe through the second water flow meter, and filter part of the sand. After the water is pumped into the hydroxyl radical strong oxidation pretreatment system through the sixth mechanical pump, the impurities in the water are removed through the bag filter; ③ The filtered water is pumped into the gas-liquid mixing equipment through the booster pump; ④ After the gas-liquid mixing The resulting hydroxyl radical solution enters the decompression buffer, and the pressure at the outlet end of the gas-liquid miscibility equipment is reduced through the decompression buffer, enhancing the hydrodynamic cavitation effect of the oxygen-active group gas and the gas-liquid miscibility of the aqueous solution, prolonging the bursting and The reaction time of water contact collision provides extreme reaction conditions for the plasma chemical reaction generating hydroxyl radicals, and a high concentration hydroxyl radical solution is prepared;

In step 1), the pore size of the bag filter may be 20-50 μm, which is used to filter organic suspended solids and particulate matter in the water body, and reduce the consumption of hydroxyl radicals by water turbidity; the hydroxyl radicals are strong The oxygen flux of the oxidation pretreatment device is 8-10 m ³ /h, the concentration of oxygen-active groups generated by atmospheric pressure electric field discharge is 100-300 mg/L, and the gas generation of oxygen-active groups is 200-400 g/h. The water flow rate of water entering the water jet cavitation liquid-liquid dissolving device is more than 40m ³ /h. Through the high-efficiency gas-liquid miscibility equipment, the oxygen-active group gas in the water generates a high-concentration hydroxyl radical solution through free radical chain reaction, and the total oxidant concentration It is 10～20mg/L, and the power of the whole machine is less than 20kW;

3) Open the solenoid valve corresponding to the hydroxyl radical strong oxidation pretreatment equipment through the central control system, the water source water in the main pipeline enters the main water inlet of the first water jet cavitation liquid dissolving device, and the first water jet cavitation liquid dissolves. The high-concentration hydroxyl radical solution inhaled by the water inlet on the side of the liquid dissolving device is fully mixed and reacted, and the second residual chlorine online monitor detects the total oxidant concentration in the pipeline; water to be tested. Hydroxyl free radicals can effectively kill plankton, pathogens, etc. in the water source water, and improve the water quality;

In step 3), the first water jet cavitation liquid-liquid dissolving device can be selected to open 1-5 venturi jets according to the treatment capacity of the water to be treated, the water flow is 300-500 m ³ /h, and the liquid The miscibility reaction time is 6～20s, and the total oxidant concentration is 1.0～2.0mg/L. The negative pressure jet effect of the venturi jet produces violent shock waves, micro jets and water flow agitation, which promotes the efficient miscibility of the hydroxyl radical solution and the water to be treated, and greatly improves the contact between hydroxyl radicals and algae, pathogenic microorganisms and organic pollutants. The collision probability and efficiency ensure that hydroxyl radicals can efficiently kill algae and microorganisms, and oxidatively degrade organic matter. After pretreatment of high algae water, the total algae density should be less than 500 cells/mL, no disinfection by-products will be generated, and the water quality index should reach the national surface water class III or above standard.

4) The water pretreated by the strong oxidation of hydroxyl radicals enters the coagulation sedimentation tank, and the coagulant is added to the coagulation sedimentation tank. Catching and other effects remove difficult-to-settlement colloids and small suspended solids in water. The coagulation and sedimentation tank adopts a mesh structure, which has the advantages of short flocculation time, good flocculation effect and simple structure;

In step 4), the type of the coagulation sedimentation tank is advection, the plane of the tank body is rectangular, the inlet and the outlet are located at both ends of the tank length, the tank length is 107.4m, the width is 16.5m, the height is 4.0m, and the liquid level distance Top 0.40m. The hydraulic load on the surface of the coagulation sedimentation tank is 1.0～2.0m ³ /(m ² ·h), and the hydraulic retention time is 160～180min. The designed dosage of coagulant is 15-20mg/L, and the stirring rate is 48-73r/min. After the debugging is stable, the turbidity of the precipitated water does not exceed 3.0NTU.

5) Open the fourth solenoid valve, pump the water after coagulation and sedimentation into the sand filter tank through the third mechanical pump, and remove the suspended substances and colloids in the water through resistance interception, gravity sedimentation and physical adsorption. Suspended substances are mainly removed from the upper layer of the filter tank by the effect of resistance interception; suspended particles and colloids with smaller particle size are mainly removed from the lower layer of the filter bed by gravity sedimentation and physical adsorption. water testing;

In step 5), the height of the filter bed of the sand filter tank can be 1.2m, which is mainly filled with quartz sand with a particle diameter of 0.9-1.2mm. The uniformity coefficient k ₈₀ is less than 1.3; the cross-sectional area of the filter bed is 78m ² , and the designed filtration speed is 7-10m/h.

6) When the algae density in the raw water is higher than 1000cells/mL, in order to further treat the micro-polluted organic matter that may be generated in the water body, the hydroxyl radical mineralization organic pollutant system is turned on through the central control system;

7) The specific operation steps of the hydroxyl radical mineralizing organic pollutant device in the hydroxyl radical mineralizing organic pollutant system are the same as in step 2).

In step 7), in the device for mineralizing organic pollutants by hydroxyl radicals, the amount of gas generated by atmospheric pressure ionization discharge ionization and dissociation of oxygen to generate oxygen-active group gas is controlled by the number of plasma modules, and the oxygen flux is 5-8m ³ /h, the oxygen active group gas concentration is 100-300 mg/L, and the oxygen active group gas generation amount is 100-300 g/h. The water flow rate of the sand filtration water entering the hydroxyl radical mineralization organic pollutant device is >40m ³ /h. Through the high-efficiency gas-liquid miscibility equipment, the oxygen-active group gas in the water generates a high-concentration hydroxyl radical solution through a free radical chain reaction. The total oxidant concentration is 5-15mg/L, and the power of the whole machine is less than 20kW.

8) Open the 5th solenoid valve corresponding to the hydroxyl radical mineralization organic pollutant system in the main pipeline through the central control system, close the 6th solenoid valve, and the sand-filtered water in the main pipeline enters the first water jet cavitation liquid to dissolve The main water inlet of the device is fully mixed and reacted with the high-concentration hydroxyl radical solution sucked in by the water inlet of the first water jet cavitation liquid dissolving device. The fourth residual chlorine online monitor measures the total oxidant concentration in the pipeline. Open the water intake valve of the 4th unit, hydroxyl radicals oxidize and degrade organic pollutants such as algal toxins and odor-causing substances, and at the same time sterilize and disinfect;

In step 8), the first water jet cavitation liquid-liquid dissolving device can choose to open 1-5 venturi jets according to the treatment capacity of the water to be treated, the water flow is 300-500 m ³ /h, and the liquid-liquid The miscibility reaction time is 6～20s, and the total oxidant concentration is 0.3～1.0mg/L. The negative pressure ejection of the venturi jet produces violent shock waves, micro-jets and water flow agitation, which promotes the efficient mixing of the hydroxyl radical solution and the water to be treated, and the extreme reaction conditions of high temperature and high pressure immediately after the cavitation bubbles burst, greatly improving the free radicals of hydroxyl groups. The reaction rate of oxidative degradation of organic pollutants by the base ensures the mineralization of organic pollutants and sterilization and disinfection at the same time. Microcystins were not detected after treatment, odor substances 2-MIB and GSM < 10ng/L, no odor and odor, chromaticity < 5 degrees, turbidity drop less than 0.3NTU, COD _Mn less than 1.0mg/L , No biological toxicity, no disinfection by-products, the water quality indicators can meet the national "Drinking Water Sanitation Standard" (GB5749-2006).

9) When the algae density in the water source water is lower than 1000cells/mL, the conventional water treatment process is adopted, and the 5th solenoid valve corresponding to the hydroxyl radical mineralization organic pollutant system is closed through the central control system 1, and the 6th solenoid valve is opened to start the sodium hypochlorite. Sterilization unit. The central control system turns on the 9th solenoid valve of the sodium hypochlorite disinfection unit, turns on the 7th mechanical pump through the 4th controller, regulates the dosage of sodium hypochlorite, and pumps the sodium hypochlorite mother liquor from the sodium hypochlorite storage tank into the main pipeline to disinfect and sterilize the sand filtration effluent;

In step 9), the concentration of the sodium hypochlorite mother liquor can be 100～120g/L, the dosage of the mother liquor is controlled at 5～10m ³ /h, the concentration is 1.6～1.7mg/L, and the residual chlorine concentration in the factory water is controlled at 0.3mg /L.

10) The drinking water treated with hydroxyl radicals or sodium hypochlorite enters the clear water pool, and the clear water pool is used to adjust the flow difference between the water production volume and the water supply volume of the pump station. Open the water intake valve of Unit 5 and test the water samples after disinfection. When the index of drinking water after treatment reaches the national "Drinking Water Sanitation Standard" (GB5749-2006), the 8th mechanical pump and the 10th solenoid valve are turned on, and the treated water flowing through the clear water pool is passed into the pipe network for residents to use.

The invention utilizes the high-concentration hydroxyl radical solution prepared by atmospheric pressure ionization discharge, which can quickly and efficiently kill microalgae blooms, and at the same time mineralize micro-polluted organic pollutants, without the generation of disinfection by-products, and improve the water quality. The indicators of drinking water after treatment have reached the national "Drinking Water Sanitation Standard" (GB5749-2006).

Combined with the conventional water treatment process of drinking water plants, the present invention is provided with OH strong oxidation pretreatment - coagulation sedimentation - sand filtration - OH mineralization organic pollutants - clear water tank between the water source water and the water supply pipe network. module.

The technical effects and advantages of the present invention are as follows:

1) The daily processing capacity of high-algae drinking water for a single hydroxyl radical technology equipment is 12,000 tons/day. Pollutants—Clear Water Pool—Pipe Network”, which can provide safe water supply for 1.5 million people per day, and all indicators of drinking water after treatment meet the “Sanitation Standards for Drinking Water” (GB5749-2006);

2) Manifold OH strong oxidation pretreatment and mineralization of organic pollutants technical equipment, by opening the number of modular array plasma integrated sources, regulating the generation of oxygen active group gas, atmospheric pressure strong ionization discharge to generate oxygen activity The concentration of radical gas is 100-300mg/L; the concentration of preparing hydroxyl radical solution is 5-20mg/L, and the maximum treatment capacity of high-algae drinking water is 500 tons/hour; the equipment can realize automatic control, and the power of the whole machine is less than 20kW, the increased operating cost is only 0.01-0.02 yuan per ton of water, and the container volume is 3.5m×1.5m×2m, which can be transported by vehicle.

3) Water jet cavitation liquid-liquid dissolving device, the negative pressure jet effect of the venturi jet produces violent shock waves, micro jets and water flow agitation, which promotes the efficient miscibility of hydroxyl radical solution and water to be treated, and greatly improves hydroxyl radicals. The probability and efficiency of contact and collision with algae, pathogenic microorganisms and organic pollutants ensure that hydroxyl radicals can efficiently kill algae and microorganisms, and oxidize and degrade organic matter; the maximum water flow of the equipment is 500m ³ /h, and there are only conventional 1/20 of the miscibility technology.

4) OH strong oxidation to kill bloom microalgae: OH solution is injected into the pipeline for transporting high-algae drinking water, and the treatment time is 6 to 20s. The dosage of OH solution is 1.0 to 2.0 mg/L. After algal water pretreatment, the total algae density is reduced to 500 cells/mL, reaching the national surface water class III or higher standard;

5) OH mineralized organic pollutants: OH solution is injected into the pipeline for transporting high-algae drinking water, the treatment time is 6-20s, the dosage of OH solution is 0.3-1.0mg/L, and the microcapsules are treated after treatment. Algal toxin-LC was not detected, odor substances 2-MIB and GSM<10ng/L;

6) Disinfection by-products after OH treatment, bromate, formaldehyde, and organic halogens such as chlorite, chlorate, haloalkane, haloacetic acid, haloacetaldehyde, chlorophenol, etc. were not detected;

7) OH kills pathogenic microorganisms in drinking water, without any odor and odor, chromaticity <5 degrees, turbidity less than 0.3NTU, organic comprehensive index COD _Mn less than 1.0mg/L, no biological toxicity, after OH treatment All indicators meet the "Drinking Water Sanitation Standard" (GB5749-2006).

Description of drawings

Figure 1 is a flow chart of a combined treatment system for efficiently killing algal blooms and mineralized organic pollutants with a daily treatment of 12,000 tons of hydroxyl radicals.

Figure 2 is the chromatogram of OH oxidative degradation of MC-LR.

Figure 3 is the chromatogram of OH oxidative degradation of 2-MIB.

Figure 4 is a chromatogram of oxidative degradation of GSM by OH.

Detailed ways

The following embodiments will further illustrate the present invention in conjunction with the accompanying drawings.

Referring to FIG. 1, the embodiment of the present invention is provided with a hydroxyl radical strong oxidation pretreatment system A, a hydroxyl radical mineralization organic pollutant system B, a sodium hypochlorite disinfection unit C, a central control system 1, residual chlorine online monitors 21-25, Coagulation sedimentation tank 3, sand filter tank 4, clear water tank 5, sodium hypochlorite storage tank 6, mechanical pump 71-78, controller 81-84, water flow meter 91-93, solenoid valve 101-1010 and unit water outlet valve 111- 115.

The hydroxyl radical strong oxidation pretreatment system A is provided with a hydroxyl radical strong oxidation pretreatment device A1 , a first water jet cavitation liquid-liquid dissolving device A2 and a first residual chlorine online monitor 22 .

The hydroxyl radical mineralization organic pollutant system B includes a hydroxyl radical mineralization organic pollutant device B1 , a second water jet cavitation liquid-liquid dissolving device B2 , and a second residual chlorine online monitor 24 .

The hydroxyl radical strong oxidation pretreatment device A1 and the mineralized organic pollutant technical equipment B1 are equipped with an atmospheric pressure strong ionization discharge oxygen plasma integrated source, a partition excitation type high-frequency high-voltage power supply, a Venturi gas-liquid mixer, a booster Pumps, decompression buffers, bag filters and cooling water circulation equipment.

The first water jet cavitation liquid dissolving device A2 and the second water jet cavitation liquid dissolving device B2 are provided with 5 Venturi jets in parallel, the first water jet cavitation liquid dissolving device A2 and the second The main water inlet of the water jet cavitation liquid dissolving device B2 is connected to the main water supply pipeline, and the side water inlets of the first water jet cavitation liquid dissolving device A2 and the second water jet cavitation liquid dissolving device B2 are connected to high-concentration hydroxyl groups At the water outlet of the free radical generating equipment, choose to open 1 to 5 venturi jets to process 300 to 500 m ³ /h of high-algae water, which is used for high-concentration hydroxyl radical solution and high-efficiency liquid-liquid miscibility of the treated water.

Described sodium hypochlorite disinfection unit C is provided with sodium hypochlorite storage tank 6, the 5th residual chlorine online monitor 25, the 9th solenoid valve 109, the 7th mechanical pump 77, the 4th controller 84 and the 3rd flowmeter 93; It can realize automatic dosing of sodium hypochlorite solution, inactivate bacteria, viruses and protozoa in water, control the regrowth of microorganisms in the process of water distribution and inhibit the growth of biofilm on the pipe wall.

The central control system 1 automatically adjusts the concentration and injection amount of oxygen-active particles generated in the plasma integrated source according to the detection results returned by the residual chlorine online monitor, such as algae concentration, chemical oxygen demand COD, pH, turbidity and other parameters. , to achieve automatic control of the concentration of hydroxyl radical solution in high concentration hydroxyl radical generating equipment. In addition, the central control system 1 can control the opening and closing of the solenoid valve in the system, control the opening and closing of the mechanical pump, and the opening and closing of the sodium hypochlorite disinfection unit through the controller, so as to realize the automatic control during the operation of the entire treatment equipment.

The water source water to be treated is connected to the water inlet of the first mechanical pump 71 of the main treatment pipeline, a first solenoid valve 101 is provided between the source water to be treated and the first mechanical pump 71, and the water outlet of the first mechanical pump 71 is connected The water inlet of the first water flow meter 91, the water outlet of the first water flow meter 91 is connected to the water inlet of the first residual chlorine on-line monitor 21, and the water outlet of the first residual chlorine on-line monitor 21 is divided into two channels, one of which is connected to the second machine The water inlet of the pump 72, the second mechanical pump 72 is provided with the first controller 81, the second solenoid valve 102 and the first unit water outlet valve 111 are provided between the first residual chlorine online monitor 21 and the second mechanical pump 72, The water outlet of the second mechanical pump 72 is connected to the main water inlet of the first water jet cavitation liquid dissolving device A2 in the hydroxyl radical strong oxidation pretreatment system A, and the water outlet of the first water jet cavitation liquid dissolving device A2 is connected to the second water jet cavitation liquid dissolving device A2. The water inlet of the residual chlorine online monitor 22,

The water outlet of the second residual chlorine online monitor 22 is connected to the water inlet of the coagulation sedimentation tank; the other outlet of the first residual chlorine online monitor 21 is directly connected to the water inlet of the coagulation sedimentation tank 3, and the first residual chlorine online monitor 21 A third solenoid valve 103 is arranged between the water outlet and the water inlet of the coagulation sedimentation tank 3, and a second unit is arranged between the water outlet of the hydroxyl radical strong oxidation pretreatment system A and the water inlet of the coagulation sedimentation tank 3 Outlet valve 112.

The water outlet of the coagulation sedimentation tank 3 is connected to the water inlet of the third mechanical pump 73 , and a fourth solenoid valve 104 is provided between the water outlet of the coagulation sedimentation tank 3 and the water inlet of the third mechanical pump 73 . The water outlet of the third mechanical pump 73 is connected to the water inlet of the sand filter tank 4, the water outlet of the sand filter tank 4 is connected to the water inlet of the fifth mechanical pump 75, and the water outlet of the fifth mechanical pump 75 is connected to the water inlet of the third residual chlorine online monitor 23 , a third unit water outlet valve 113 is provided between the water outlet of the fifth mechanical pump 75 and the third residual chlorine online monitor 23 . The water outlet of the third residual chlorine online monitor 23 is divided into two channels, one is connected to the water inlet of the fourth mechanical pump 74, and the water outlet of the fourth mechanical pump 74 is connected to the first water jet in the hydroxyl radical mineralization organic pollutant system B. The main water inlet of the liquid dissolving device B2, the water outlet of the first water jet cavitation liquid dissolving device B2 is connected to the water inlet of the fourth residual chlorine online monitor 24, and the water outlet of the fourth residual chlorine online monitor 24 is connected to water Treatment main line; the other way of the water outlet of the third residual chlorine online monitor 23 is directly connected to the clean water tank 5 through the water treatment main line. A sixth solenoid valve 106 is arranged between the water outlet of the third residual chlorine online monitor 23 and the water inlet of the clean water pool 5 , and between the water outlet of the hydroxyl radical mineralization organic pollutant system B and the water inlet of the clean water pool 5 The fourth unit water outlet valve 114 .

A sodium hypochlorite disinfection unit C is arranged between the water outlet of the hydroxyl radical mineralization organic pollutant system B and the water inlet of the clear water pool 5 . The water outlet of the sodium hypochlorite storage tank 6 is connected to the water inlet of the fifth residual chlorine online monitor 25, and the ninth solenoid valve 109 and the seventh mechanical pump 77 are arranged between the water outlet of the fifth residual chlorine online monitor 25 and the main water treatment pipeline. With the third water flow meter 93 , the central control system 1 controls the opening of the seventh mechanical pump 77 via the fourth controller 84 .

The main water treatment pipeline between the water outlet of the sand filter 4 and the water inlet of the clear water tank 5 is divided into a branch water treatment pipeline, which is used for preparing a high-concentration hydroxyl radical solution. The water treatment branch line is connected to the water inlet of the second water flow meter 92 , and the water outlet of the second water flow meter 92 is connected to the water inlet of the sixth mechanical pump 76 . The water outlet of the sixth mechanical pump 76 of the branch pipeline is divided into two paths, and the other is connected to the water inlet of the hydroxyl radical strong oxidation pretreatment device A1 in the hydroxyl radical strong oxidation pretreatment system A, and the hydroxyl radical strong oxidation pretreatment device A1 The water outlet is connected to the water inlet of the first water jet cavitation liquid dissolving device A2; the other way of the water outlet of the sixth mechanical pump 76 of the branch pipeline is connected to the hydroxyl radical mineralization organic pollutant in the hydroxyl radical mineralization organic pollutant device B. The water inlet of the pollutant device B1 and the water outlet of the hydroxyl radical mineralization organic pollutant device B1 are connected to the branch water outlet of the first water jet cavitation liquid dissolving device B2.

The water outlet of the clean water pool 5 is connected to the water inlet of the eighth mechanical pump 78, and the fifth unit water outlet valve 115 and the tenth solenoid valve 1010 are provided between the water outlet of the clean water pool 5 and the water inlet of the eighth mechanical pump 78, and the eighth mechanical The water outlet of the pump 78 is connected to the pipe network.

The method for efficiently killing algal blooms and mineralized organic pollutants by hydroxyl radicals comprises the following steps:

1) Open the first solenoid valve 101 and the first mechanical pump 71 of the main line, suck in the water source water to be treated, and control the flow rate of the water by the first water flow meter 91 . The water source water is detected by the first residual chlorine online monitor 21 , and the detection results are fed back to the central processing system 1 . When it is detected that the density of algae is higher than 1000cells/mL, the hydroxyl radical strong oxidation pretreatment system A is activated, and the central control system 1 determines the dosage of hydroxyl radical solution to be added according to parameters such as algae concentration, COD, water turbidity, etc. The signal is sent to the hydroxyl radical strong oxidation pretreatment device A1. When it is detected that the algae density is lower than 1000cells/mL, the hydroxyl radical strong oxidation pretreatment system A is not turned on, the second solenoid valve 102 is closed, the third solenoid valve 103 is opened, and the water source water is directly pumped into the coagulation sedimentation tank 3 . The water flow in the main pipeline is 300-500 m ³ /h.

2) Hydroxy radical strong oxidation pretreatment equipment Efficient preparation of hydroxyl radical solution includes the following steps: ① Open the oxygen active group gas generating equipment A1 in the hydroxyl radical strong oxidation pretreatment equipment, and pass the oxygen in the oxygen cylinder into the plasma The plasma generation module activates the high-frequency high-voltage power supply corresponding to the plasma module, forms an atmospheric pressure ionization discharge in the gap of the extremely narrow discharge, and ionizes and dissociates the oxygen to generate a high-concentration oxygen-active group gas. The number of plasma modules is controlled; 2. Turn on the sixth mechanical pump 76 of the branch pipeline and the seventh solenoid valve 107 corresponding to the water flow path of the branch pipeline of the hydroxyl radical strong oxidation pretreatment system, and control the water flow of the branch pipeline through the second water flow meter 92, Part of the water after sand filtration is pumped into the hydroxyl radical strong oxidation pretreatment system A1 through the sixth mechanical pump 76, and the impurities in the water are removed through the bag filter; 3. The filtered water is pumped into the gas-liquid mixing equipment through a booster pump; ④ The hydroxyl radical solution after gas-liquid miscibility enters the decompression buffer, and the pressure at the outlet end of the gas-liquid miscibility equipment is reduced through the decompression buffer to enhance the hydrodynamic cavitation effect of oxygen-active group gas and water solution gas-liquid miscibility , prolonging the reaction time of microbubble bursting and contacting and colliding with water, providing extreme reaction conditions for the plasma chemical reaction generating hydroxyl radicals, and preparing a high-concentration hydroxyl radical solution.

The pore size of the bag filter is 20-50 μm, which is used for filtering organic suspended matter and particulate matter in the water body and reducing the consumption of hydroxyl radicals by water turbidity; the oxygen supply of the hydroxyl radical strong oxidation pretreatment device The concentration of oxygen-active groups generated by atmospheric pressure electric field discharge is 100-300 mg/L, and the gas production of oxygen ^- active groups is 200-400 g/h, and the sand filtered water enters the water jet cavitation liquid The water flow rate of the liquid dissolving device is >40m ³ /h. Through the high-efficiency gas-liquid miscibility equipment, the oxygen-active group gas generates a high-concentration hydroxyl radical solution through the free radical chain reaction in water, and the total oxidant concentration is 10～20mg/L, The power of the whole machine is less than 20kW.

3) Open the solenoid valve corresponding to the hydroxyl radical strong oxidation pretreatment equipment A1 through the central control system 1, the water source water in the main pipeline enters the main water inlet of the first water jet cavitation liquid dissolving device A2, and the first water jet The high-concentration hydroxyl radical solution sucked in by the water inlet of the cavitation liquid-liquid dissolving device A2 undergoes a sufficient mixing reaction. The second residual chlorine online monitor 22 detects the total oxidant concentration in the pipeline. The water intake valve 112 of the second unit is opened, and the water after the strong oxidation treatment of hydroxyl radicals is detected. Hydroxyl free radicals can effectively kill plankton, pathogens, etc. in the water source water, and improve the water quality.

The first water jet cavitation liquid-liquid dissolving device A2 can be selected to open 1-5 venturi jets according to the treatment capacity of the water to be treated, the water flow is 300-500 m ³ /h, and the liquid-liquid miscibility reaction time is 6～20s, the total oxidant concentration is 1.0～2.0mg/L. The negative pressure jet effect of the venturi jet produces violent shock waves, micro jets and water flow agitation, which promotes the efficient miscibility of the hydroxyl radical solution and the water to be treated, and greatly improves the contact between hydroxyl radicals and algae, pathogenic microorganisms and organic pollutants. The collision probability and efficiency ensure that hydroxyl radicals can efficiently kill algae and microorganisms, and oxidatively degrade organic matter. After pretreatment of high algae water, the total algae density should be less than 500 cells/mL, no disinfection by-products will be generated, and the water quality index should reach the national surface water class III or above standard.

4) The water pretreated by the strong oxidation of hydroxyl radicals enters the coagulation sedimentation tank 3 . Add coagulant to the coagulation sedimentation tank to remove difficult-to-settlement colloids and fine suspended solids in the water by compressing the electric double layer, adsorption-electric neutralization, adsorption-bridging, and sediment net capture. The coagulation sedimentation tank adopts a mesh structure, which has the advantages of short flocculation time, good flocculation effect and simple structure.

The type of the coagulation sedimentation tank is advection, the plane of the tank body is rectangular, the inlet and the outlet are located at both ends of the tank length, the tank length is 107.4m, the width is 16.5m, the height is 4.0m, and the liquid level is 0.40m from the top. The hydraulic load on the surface of the coagulation sedimentation tank is 1.0～2.0m ³ /(m ² ·h), and the hydraulic retention time is 160～180min. The designed dosage of coagulant is 15-20mg/L, and the stirring rate is 48-73r/min. After the debugging is stable, the turbidity of the precipitated water does not exceed 3.0NTU.

5) Open the fourth solenoid valve 104, pump the coagulated and precipitated water into the sand filter tank 4 through the third mechanical pump 73, and remove suspended substances and colloids in the water through resistance interception, gravity sedimentation and physical adsorption. Suspended substances with larger particle diameters are mainly removed in the upper layer of the filter by the effect of resistance interception; suspended particles and colloids with smaller particle diameters are mainly removed in the lower layer of the filter bed by gravity sedimentation and physical adsorption. The water intake valve 113 of the third unit is opened, and the water after the sand filtration is detected.

The filter bed height of the sand filter tank is 1.2m, which is mainly filled with quartz sand with a particle diameter of 0.9-1.2mm. From top to bottom, a single layer of uniform particle filter material is used, and the non-uniformity coefficient k ₈₀ is less than 1.3; The cross-sectional area of the filter bed is 78m ² , and the designed filtration speed is 7-10m/h.

6) When the algae density in the raw water is higher than 1000cells/mL, in order to further treat the micro-polluted organic matter that may be generated in the water body, the central control system 1 is used to open the hydroxyl radical mineralization organic pollutant system B.

7) The specific operation steps of the device B1 for mineralizing organic pollutants by hydroxyl radicals in the system B for mineralizing organic pollutants by hydroxyl radicals are the same as in step 2).

The hydroxyl radical mineralization organic pollutant device B1, the atmospheric pressure ionization discharge ionization and dissociation of oxygen to generate oxygen-active group gas is controlled by the number of plasma modules, the oxygen flux is 5-8 m ³ /h, The concentration of radical gas is 100～300mg/L, and the generation amount of oxygen-active radical gas is 100～300g/h. The water flow rate of the sand filtration water entering the hydroxyl radical mineralization organic pollutant device is >40m ³ /h. Through the high-efficiency gas-liquid miscibility equipment, the oxygen-active group gas in the water generates a high-concentration hydroxyl radical solution through a free radical chain reaction. The total oxidant concentration is 5-15mg/L, and the power of the whole machine is less than 20kW.

8) Open the fifth solenoid valve 105 corresponding to the hydroxyl radical mineralization organic pollutant system B in the main pipeline through the central control system 1, close the sixth solenoid valve 106, and the sand-filtered water in the main pipeline enters the first water jet space. The main water inlet of the cavitation liquid dissolving device B2 is fully mixed and reacted with the high-concentration hydroxyl radical solution sucked in by the water inlet of the first water jet cavitation liquid dissolving device B2. The fourth residual chlorine online monitor 24 measures the total oxidant concentration in the pipeline. Open the water intake valve 114 of the fourth unit, and hydroxyl radicals oxidize and degrade organic pollutants such as algal toxins and odor-causing substances, and at the same time sterilize.

The first water jet cavitation liquid-liquid dissolving device B2 can choose to open 1 to 5 venturi jets according to the treatment amount of the water to be treated, the water flow is 300 to 500 m ³ /h, and the liquid-liquid miscibility reaction time is 6～20s, the total oxidant concentration is 0.3～1.0mg/L. The negative pressure jet effect of the venturi jet produces violent shock waves, micro jets and water flow agitation, which promotes the efficient mixing of the hydroxyl radical solution and the water to be treated. The extreme reaction conditions of high temperature and high pressure in the instant of cavitation bubble rupture greatly increase the reaction rate of hydroxyl radical oxidation and degradation of organic pollutants, ensure the mineralization of organic pollutants, and at the same time sterilize. Microcystins were not detected after treatment, odor substances 2-MIB and GSM < 10ng/L, no odor and odor, chromaticity < 5 degrees, turbidity drop less than 0.3NTU, COD _Mn less than 1.0mg/L , No biological toxicity, no disinfection by-products, the water quality indicators can meet the national "Drinking Water Sanitation Standard" (GB5749-2006).

9) When the algae density in the water source water is lower than 1000cells/mL, the conventional water treatment process is adopted, and the fifth solenoid valve 105 corresponding to the hydroxyl radical mineralization organic pollutant system B is closed through the central control system 1, and the sixth solenoid valve 106 is opened. , start the sodium hypochlorite disinfection unit C. The central control system 1 opens the ninth solenoid valve 109 of the sodium hypochlorite disinfection unit, opens the seventh mechanical pump 77 through the fourth controller 84, regulates the dosage of sodium hypochlorite, and pumps the sodium hypochlorite mother liquor from the sodium hypochlorite storage tank 6 into the main pipeline to filter the sand. Disinfection and sterilization of water.

The concentration of the sodium hypochlorite mother solution is 100-120 g/L, the dosage of the mother solution is controlled at 5-10 m ³ /h, the concentration is 1.6-1.7 mg/L, and the residual chlorine concentration in the factory water is controlled at 0.3 mg/L.

10) The drinking water treated with hydroxyl radicals or sodium hypochlorite enters the clear water tank 5, and the clear water tank 5 is used to adjust the flow difference between the water production volume and the water supply volume of the pump station. Open the water intake valve 115 of the fifth unit to test the water sample after disinfection. When the treated drinking water index reaches the national "Drinking Water Sanitation Standard" (GB5749-2006), turn on the 8th mechanical pump 78 and the 10th solenoid valve 1010, and pass the treated water after passing through the clear water pool into the pipe network for residents to use .

The invention utilizes the high-concentration hydroxyl radical solution prepared by atmospheric pressure ionization discharge, which can quickly and efficiently kill microalgae blooms, and at the same time mineralize micro-polluted organic pollutants, without the generation of disinfection by-products, and improve the water quality. The indicators of drinking water after treatment have reached the national "Drinking Water Sanitation Standard" (GB5749-2006).

Specific embodiment: the treatment capacity is 12,000 tons/day, and the combined system uses OH strong oxidation to treat high algae water source water and sand filtration sedimentation water.

According to the method and system of the present invention, 12,000 tons/day of hydroxyl radicals are developed to efficiently kill algal bloom microalgae and mineralized organic pollutants, and a combined treatment system is developed. The experimental site of the 12,000-ton/day high-algae drinking water strong oxidation emergency treatment technology demonstration project is located in Xiang'an Water Plant, Xiang'an District, Xiamen City. The total algae density of the source water to be treated was 1.79×10 ⁵ cells/mL, of which the densities of Microcystis, Pseudo-Anabaena, Cyclotella and other algae were 1.75×10 ⁵ , 1.73×10 ³ , and 8.10×10 ² , respectively. and 1.23×10 ³ cells/mL, thus turning on the hydroxyl radical strong oxidation pretreatment unit. The concentration of microcystins in the sand filtration water was 8.6 μg/L; the concentrations of di-methyl isocamphenol and geosmin were 88.8 and 95.3 ng/L, respectively, so the hydroxyl radical mineralization organic pollutant unit was turned on. The water source water to be treated is extracted by a mechanical pump. The water treatment capacity of the main pipeline is 500 tons/hour, and the water flow rate of the branch pipeline flowing into the OH strong oxidation pretreatment unit and the OH mineralized organic pollutant unit is 55 tons/hour. Ensure that the total oxidant concentration is 1.0mg/L after the mixed reaction of the OH strong oxidation pretreatment unit and the main water during the treatment process, and the total oxidant concentration after the mixed reaction of the OH mineralized organic pollutant unit is 0.5mg/L, and the treatment time is 20s. Open the water outlet valve of the unit to take samples, and test the treated water samples.

The killing of algae by the combined system·OH strong oxidation and disinfection process is shown in Table 1. The identification of cell death was performed by SYTOX Green fluorescence staining microscope counting method. The cell membrane permeability of dead algal cells changes, and SYTOXGreen dye macromolecules can enter the cells and emit green fluorescence under excitation at 488nm. However, the cell membrane function of the surviving algal cells is intact, and the dye macromolecules cannot enter the cell body. Under the excitation of 488nm, they will not emit green fluorescence, but only show the spontaneous red fluorescence of chlorophyll, which can determine the life and death of the algal cells. The total algae density in the high-algae water source water was 1.79×10 ⁵ cells/mL. After 20s of strong oxidation with ·OH, only 250cells/mL of Microcystis and a small amount of other algae survived, and the rest of the algae species were all killed, meeting the requirements of the water plant. Incoming water requirements. The algal cells were completely killed by the strong oxidation of ·OH in the sand-filtered water.

Table 1

The oxidative degradation of organic pollutants by the OH disinfection treatment process is shown in Figures 2-4. The concentration of total oxidant in the sand filtration water was 0.5 mg/L. After 20s of treatment, the concentration of microcystins was lower than the detection limit. The degradation rates of odor-causing substances 2-methylisocamphenol and geosmin after OH disinfection treatment were 91% and 96%, respectively, and the concentration after treatment was lower than 10ng/L, which met my country's "Drinking Water Hygiene Standard" (GB5749-2006 ).

·The situation of OH strong oxidation and disinfection process to generate disinfection by-products is shown in Table 2. In the treated water samples, chlorite, bromate, formaldehyde, bromomethane, dichloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, dichloroacetic acid, trichloromethane Disinfection by-products such as chloroacetic acid, 2,4,6-trichlorophenol and halogenated alkanes were not detected, indicating that the risk of disinfection by-products is small when ·OH oxidation is used to treat drinking water.

Table 2

·The water quality of OH strong oxidation and disinfection treatment process is shown in Table 3. In the water source water and sand filtration water treatment test, after OH strong oxidation treatment for 20s, the killing effect of total bacteria, total coliform, fecal coliform and Escherichia coli in the water was remarkable, and the four types of bacteria indicators all reached the national level. drinking water standards. No significant changes were found in other water quality indicators of source water and sand filtration effluent before and after treatment, and there was no biological toxicity. All conventional water quality indicators could meet the national "Drinking Water Sanitation Standard" (GB5749-2006).

table 3

In summary, the use of OH strong oxidation process to treat high-algae source water can quickly and efficiently kill algae, and at the same time oxidize and degrade mineralized organic pollutants, without the formation of disinfection by-products, and the microbiological and sensory properties of drinking water after treatment. It meets the national "Drinking Water Sanitation Standard" (GB5749-2006), the water body has no biological toxicity, and the safety of drinking water quality is effectively guaranteed. The research results can provide technical support for the safe supply of drinking water in high algae water sources in my country.

Claims (8)

1. The system is characterized by being provided with a hydroxyl radical strong oxidation pretreatment system, a hydroxyl radical mineralized organic pollutant system, a sodium hypochlorite disinfection unit, a central control system, a residual chlorine on-line monitor, a coagulating sedimentation tank, a sand filter tank, a clean water tank, a sodium hypochlorite storage tank, a mechanical pump, a controller, a water flow meter, an electromagnetic valve and a unit water outlet valve;

the hydroxyl radical strong oxidation pretreatment system is provided with a hydroxyl radical strong oxidation pretreatment device, a1 st water jet cavitation liquid dissolving device and a1 st residual chlorine on-line monitor;

the hydroxyl radical mineralization organic pollutant system is provided with a hydroxyl radical mineralization organic pollutant device, a No. 2 water jet cavitation liquid dissolving device and a No. 2 residual chlorine on-line monitor;

the hydroxyl radical strong oxidation pretreatment device and the technical equipment for mineralizing organic pollutants are provided with an atmospheric pressure ionization discharge oxygen plasma integrated source, a partition excitation type high-frequency high-voltage power supply, a Venturi gas-liquid mixing and dissolving device, a booster pump, a decompression buffer, a bag filter and cooling water circulating equipment;

the 1 st water jet cavitation liquid dissolving device and the 2 nd water jet cavitation liquid dissolving device are provided with 5 venturi ejectors which are connected in parallel, main water inlets of the 1 st water jet cavitation liquid dissolving device and the 2 nd water jet cavitation liquid dissolving device are connected with a main water delivery pipeline, and side water inlets of the 1 st water jet cavitation liquid dissolving device and the 2 nd water jet cavitation liquid dissolving device are connected with a water outlet of high-concentration hydroxyl radical generating equipment and are used for mixing and dissolving a high-concentration hydroxyl radical solution and a high-efficiency liquid of treated water;

the sodium hypochlorite disinfection unit is provided with a sodium hypochlorite storage tank, a 5 th residual chlorine on-line monitor, a 9 th electromagnetic valve, a 7 th mechanical pump, a 4 th controller and a 3 rd flow meter; the sodium hypochlorite disinfection unit realizes the automatic feeding of a sodium hypochlorite solution, inactivates bacteria, viruses and protozoa in water, controls the regrowth of microorganisms in the water delivery and distribution process and inhibits the growth of a pipe wall biomembrane;

the central control system automatically adjusts the concentration and the injection amount of the oxygen active particles generated in the plasma integrated source according to the detection result returned by the residual chlorine on-line monitor, wherein the detection result is parameters of algae concentration, Chemical Oxygen Demand (COD), pH and turbidity, and the automatic control of the concentration of the hydroxyl radical solution in the high-concentration hydroxyl radical generating equipment is realized; the central control system can control the opening and closing of the electromagnetic valve in the system, and the opening and closing of the mechanical pump and the opening and closing of the sodium hypochlorite disinfection unit are controlled by the controller, so that the automatic control in the operation process of the whole treatment equipment is realized;

the water source water to be treated is connected with a water inlet of a1 st mechanical pump of a main treatment pipeline, a1 st electromagnetic valve is arranged between the water source water to be treated and the 1 st mechanical pump, a water outlet of the 1 st mechanical pump is connected with a water inlet of a1 st water flow meter, a water outlet of the 1 st water flow meter is connected with a water inlet of a1 st residual chlorine on-line monitor, a water outlet of the 1 st residual chlorine on-line monitor is divided into two paths, one path is connected with a water inlet of a2 nd mechanical pump, the 2 nd mechanical pump is provided with a1 st controller, a2 nd electromagnetic valve and a1 st unit water outlet valve are arranged between the 1 st residual chlorine on-line monitor and the 2 nd mechanical pump, a water outlet of the 2 nd mechanical pump is connected with a main water inlet of a1 st cavitation liquid water jet flow dissolving device in a hydroxyl;

the water outlet of the 2 nd residual chlorine on-line monitor is connected with the water inlet of the coagulating sedimentation tank; the other path of the water outlet of the 1 st residual chlorine on-line monitor is directly connected with the water inlet of the coagulating sedimentation tank, a 3 rd electromagnetic valve is arranged between the water outlet of the 1 st residual chlorine on-line monitor and the water inlet of the coagulating sedimentation tank, and a2 nd unit water outlet valve is arranged between the water outlet of the hydroxyl radical strong oxidation pretreatment system and the water inlet of the coagulating sedimentation tank;

the water outlet of the coagulation sedimentation tank is connected with the water inlet of a 3 rd mechanical pump, a 4 th electromagnetic valve is arranged between the water outlet of the coagulation sedimentation tank and the water inlet of the 3 rd mechanical pump, the water outlet of the 3 rd mechanical pump is connected with the water inlet of a sand filter, the water outlet of the sand filter is connected with the water inlet of a 5 th mechanical pump, the water outlet of the 5 th mechanical pump is connected with the water inlet of a 3 rd residual chlorine on-line monitor, a 3 rd unit water outlet valve is arranged between the water outlet of the 5 th mechanical pump and the 3 rd residual chlorine on-line monitor, the water outlet of the 3 rd residual chlorine on-line monitor is divided into two paths, one path is connected with the water inlet of the 4 th mechanical pump, the water outlet of the 4 th mechanical pump is connected with a main water inlet of a1 st water jet cavitation liquid dissolving device in a hydroxyl radical mineralization organic pollutant system, the water outlet; the other path of the water outlet of the No. 3 residual chlorine on-line monitor is directly connected with a clean water tank through a water treatment main pipeline; a 6 th electromagnetic valve is arranged between the water outlet of the 3 rd residual chlorine on-line monitor and the water inlet of the clean water tank, and a 4 th unit water outlet valve is arranged between the water outlet of the hydroxyl radical mineralization organic pollutant system and the water inlet of the clean water tank;

a sodium hypochlorite disinfection unit is arranged between the water outlet of the hydroxyl radical mineralization organic pollutant system and the water inlet of the clean water tank, the water outlet of a sodium hypochlorite storage tank is connected with the water inlet of a 5 th residual chlorine on-line monitor, a 9 th electromagnetic valve, a 7 th mechanical pump and a 3 rd water flow meter are sequentially arranged between the water outlet of the 5 th residual chlorine on-line monitor and a water treatment main pipeline, and the central control system controls the opening of the 7 th mechanical pump through a 4 th controller;

a water treatment branch pipeline is divided from a water treatment main pipeline between the water outlet of the sand filter tank and the water inlet of the clean water tank and used for preparing high-concentration hydroxyl radical solution, the water treatment branch pipeline is connected with the water inlet of a2 nd water flowmeter, the water outlet of the 2 nd water flowmeter is connected with the water inlet of a 6 th mechanical pump, the water outlet of the 6 th mechanical pump of the branch pipeline is divided into two paths, one path is connected with the water inlet of a hydroxyl radical strong oxidation pretreatment device in a hydroxyl radical strong oxidation pretreatment system, and the water outlet of the hydroxyl radical strong oxidation pretreatment device is connected with the branch water inlet of a1 st water jet cavitation liquid dissolving device; the other path of the water outlet of the 6 th mechanical pump of the branch pipeline is connected with a water inlet of a hydroxyl radical mineralization organic pollutant device in the hydroxyl radical mineralization organic pollutant equipment, and a water outlet of the hydroxyl radical mineralization organic pollutant device is connected with a branch water inlet of the 1 st water jet cavitation liquid dissolving device;

the water outlet of the clean water tank is connected with the water inlet of the 8 th mechanical pump, a 5 th unit water outlet valve and a 10 th electromagnetic valve are arranged between the water outlet of the clean water tank and the water inlet of the 8 th mechanical pump, and the water outlet of the 8 th mechanical pump is connected with a pipe network.

2. The method for efficiently killing the water bloom microalgae and the mineralized organic pollutants by using the hydroxyl radicals is characterized in that the method for killing the water bloom microalgae and the mineralized organic pollutants by using the hydroxyl radicals comprises the following steps:

1) opening a1 st electromagnetic valve and a1 st mechanical pump of the main pipeline, sucking source water to be treated, controlling the water flow through a1 st water flow meter, detecting the source water by a1 st residual chlorine on-line monitor, and feeding back a detection result to a central processing system; when the density of algae is detected to be higher than 1000cells/mL, starting a hydroxyl radical strong oxidation pretreatment system, determining the dosage of a hydroxyl radical solution to be added by a central control system according to parameters of algae concentration, COD and water turbidity, sending a signal to a hydroxyl radical strong oxidation pretreatment device, when the density of algae is detected to be lower than 1000cells/mL, not starting the hydroxyl radical strong oxidation pretreatment system, closing a2 nd electromagnetic valve, starting a 3 rd electromagnetic valve, directly pumping source water into a coagulation sedimentation tank, wherein the water flow in a main pipeline is 300-500 m³/h；

2) The method for efficiently preparing the hydroxyl radical solution by the hydroxyl radical strong oxidation pretreatment equipment comprises the following steps:

opening oxygen active group gas generating equipment in a hydroxyl radical strong oxidation pretreatment device, introducing oxygen in an oxygen cylinder into a plasma generating module, starting a subarea excitation high-frequency high-voltage power supply corresponding to the plasma module, forming atmospheric pressure ionization discharge in an extremely narrow discharge gap, ionizing and dissociating the oxygen to generate high-concentration oxygen active group gas, wherein the generation amount of the high-concentration oxygen active group gas is controlled by the number of the started plasma modules;

opening a 7 th electromagnetic valve corresponding to a branch pipeline water flow path of a branch pipeline 6 th mechanical pump and the hydroxyl radical strong oxidation pretreatment system, controlling the water flow of the branch pipeline through a2 nd water flow meter, pumping part of sand-filtered water into the hydroxyl radical strong oxidation pretreatment system through the 6 th mechanical pump, and removing impurities in the water through a bag filter;

pumping the filtered water into a gas-liquid mixing and dissolving device through a booster pump;

the hydroxyl radical solution after gas-liquid mixing enters a decompression buffer, the pressure at the outlet end of the gas-liquid mixing equipment is reduced through the decompression buffer, the hydrodynamic cavitation effect of the gas-liquid mixing of the oxygen active radical gas and the water solution is enhanced, the reaction time of the contact collision of the burst micro bubbles and the water is prolonged, extreme reaction conditions are provided for the plasma chemical reaction for generating the hydroxyl radical, and the high-concentration hydroxyl radical solution is prepared;

3) starting a solenoid valve corresponding to the hydroxyl radical strong oxidation pretreatment equipment through a central control system, enabling source water in a main pipeline to enter a main water inlet of a1 st water jet cavitation liquid dissolving device, carrying out full mixing reaction with a high-concentration hydroxyl radical solution sucked from a side water inlet of the 1 st water jet cavitation liquid dissolving device, and detecting the total oxidant concentration in the pipeline by a2 nd residual chlorine on-line monitor; opening the water intake valve of the unit 2, detecting the water after the strong oxidation treatment of the hydroxyl radicals, and efficiently killing plankton and pathogens in the source water by the hydroxyl radicals to improve the water quality condition;

the 1 st water jet cavitation liquid dissolving device selectively opens 1-5 Venturi ejectors according to the treatment capacity of water to be treated, and the water flow is 300-500 m³The reaction time of liquid-liquid mixing and dissolving is 6-20 s, and the concentration of the total oxidant is 1.0-2.0 mg/L; the negative pressure jetting effect of the Venturi ejector generates violent shock waves, micro jet flow and water flow stirring, promotes the efficient mixing and dissolution of the hydroxyl radical solution and the water to be treated, greatly improves the contact collision probability and efficiency of the hydroxyl radical solution and algae, pathogenic microorganisms and organic pollutants, ensures that the hydroxyl radical solution can efficiently kill the algae and the microorganisms and oxidize and degrade organic matters, and ensures that the total algae density after the high algae water pretreatment is less than 500cells/mL,no disinfection by-product is generated, and the water quality index reaches the national standard of surface water above III class;

4) water after the strong oxidation pretreatment of hydroxyl radicals enters a coagulating sedimentation tank, a coagulant is added into the coagulating sedimentation tank, colloid and fine suspended matters which are difficult to settle in the water are removed through the actions of compressing a double electric layer, adsorption-electric neutralization, adsorption-bridging and sediment net catching, and the coagulating sedimentation tank adopts a grid structure;

5) opening a 4 th electromagnetic valve, pumping the water after coagulating sedimentation into a sand filter through a 3 rd mechanical pump, removing suspended substances and colloid in the water through resistance interception, gravity sedimentation and physical adsorption, wherein the suspended substances with larger particle diameter are mainly removed on the upper layer of the filter through the action of resistance interception; suspended particles and colloid with smaller particle size are removed mainly through gravity settling and physical adsorption on the lower layer of the filter bed, and a water taking valve of the unit 3 is opened to detect the water after sand filtration;

6) when the density of algae in raw water is higher than 1000cells/mL, a hydroxyl radical mineralization organic pollutant system is started through a central control system;

7) the specific operation steps of the device for mineralizing the organic pollutants by the hydroxyl radicals in the system for mineralizing the organic pollutants by the hydroxyl radicals are the same as the step 2);

8) opening a 5 th electromagnetic valve corresponding to a hydroxyl radical mineralization organic pollutant system in the main pipeline through a central control system, closing a 6 th electromagnetic valve, enabling sand-filtered water in the main pipeline to enter a main water inlet of a1 st water jet cavitation liquid dissolving device, carrying out full mixing reaction with a high-concentration hydroxyl radical solution sucked from a side water inlet of the 1 st water jet cavitation liquid dissolving device, detecting the concentration of a total oxidant in the pipeline by a 4 th residual chlorine online monitor, opening a 4 th unit water taking valve, oxidizing and degrading algal toxins and smelling substance organic pollutants by hydroxyl radicals, and sterilizing and disinfecting simultaneously;

the 1 st water jet cavitation liquid dissolving device selectively opens 1-5 Venturi ejectors according to the treatment capacity of water to be treated, and the water flow is 300-500 m³The reaction time of liquid-liquid mixing and dissolving is 6-20 s, and the concentration of the total oxidant is 0.3-1.0 mg/L; after treatment, the microcystin is not detected, and the smelling substances 2-MIB andGSM < 10ng/L, no foreign odor and odor, and chroma<5 degree, turbidity drop less than 0.3NTU, COD_MnLess than 1.0mg/L, no biotoxicity, no disinfection by-product, and all indexes of water quality reaching the national sanitary Standard for Drinking Water;

9) when the density of algae in water source water is lower than 1000cells/mL, adopting a conventional water treatment process, closing a 5 th electromagnetic valve corresponding to a hydroxyl radical mineralization organic pollutant system through a central control system 1, opening a 6 th electromagnetic valve, starting a sodium hypochlorite disinfection unit, opening a 9 th electromagnetic valve of the sodium hypochlorite disinfection unit through the central control system, opening a 7 th mechanical pump through a 4 th controller, regulating and controlling the adding amount of sodium hypochlorite, and pumping sodium hypochlorite mother liquor into a main pipeline from a sodium hypochlorite storage tank to disinfect and sterilize sand filtration effluent;

10) the drinking water treated by the hydroxyl radicals or the sodium hypochlorite enters a clean water tank, the clean water tank is used for adjusting the flow difference between the water production amount and the water supply amount of a pump station, a 5 th unit water taking valve is opened, and a water sample after the disinfection treatment is detected; and when the index of the treated drinking water reaches the national sanitary Standard for Drinking Water, the 8 th mechanical pump and the 10 th electromagnetic valve are started, and the treated water flowing through the clean water tank is introduced into a pipe network for residents to use.

3. The method for efficiently killing water bloom microalgae and mineralized organic pollutants by using the hydroxyl radicals as claimed in claim 2, wherein in the step 2), the aperture of the bag filter is 20-50 μm, and the bag filter is used for filtering organic suspended matters and particulate matters in a water body and reducing the consumption of the hydroxyl radicals caused by water turbidity.

4. The method for efficiently killing water bloom microalgae and mineralized organic pollutants according to claim 2, wherein in the step 2), the oxygen flux of the hydroxyl radical strong oxidation pretreatment device is 8-10 m³The concentration of oxygen active groups generated by atmospheric pressure electric field discharge is 100-300 mg/L, the generation amount of oxygen active group gas is 200-400 g/h, and the water flow of sand filter water entering the water jet cavitation liquid dissolving device>40m³H, passing through efficient gas-liquid mixing and dissolving equipmentThe oxygen active group gas generates a high-concentration hydroxyl radical solution through a radical chain reaction in water, the total oxidant concentration is 10-20 mg/L, and the power of the whole machine is less than 20 kW.

5. The method for efficiently killing water bloom microalgae and mineralized organic pollutants by using hydroxyl radicals as claimed in claim 2, wherein in the step 4), the coagulation sedimentation tank is in a horizontal flow type, the plane of the tank body is rectangular, the inlet and the outlet are respectively arranged at two ends of the tank length, the tank length is 107.4m, the width is 16.5m, the height is 4.0m, the distance between the liquid surface and the top is 0.40m, and the hydraulic load on the surface of the coagulation sedimentation tank is 1.0-2.0 m³/(m²H), the hydraulic retention time is 160-180 min, the designed addition amount of a coagulant is 15-20 mg/L, the stirring speed is 48-73 r/min, and the turbidity of precipitated water is not more than 3.0NTU after the regulation is stable.

6. The method for efficiently killing algal bloom and mineralized organic pollutants by using hydroxyl radicals as claimed in claim 2, wherein in step 5), the height of the filter bed of the sand filter is 1.2m, the filter bed is mainly filled with quartz sand with the particle diameter of 0.9-1.2 mm, a single-layer uniform-particle filter material is adopted from top to bottom, and the non-uniform coefficient k is₈₀Less than 1.3; the cross-sectional area of the filter bed is 78m²The filtration speed is designed to be 7-10 m/h.

7. The method for efficiently killing algal bloom microalgae and mineralized organic pollutants by using hydroxyl radicals as claimed in claim 2, wherein in the step 7), the amount of the generated oxygen active group gas generated by the hydroxyl radical mineralized organic pollutants device through ionization and dissociation of oxygen by atmospheric pressure ionization discharge is controlled by the number of the plasma modules, and the oxygen flux is 5-8 m³The concentration of the oxygen active group gas is 100-300 mg/L, and the generation amount of the oxygen active group gas is 100-300 g/h; water flow of sand filter water entering hydroxyl radical mineralization organic pollutant device>40m³H, through efficient gas-liquid mixing equipment, generating high-concentration hydroxyl radical solution through radical chain reaction of oxygen active group gas in water, wherein the total oxidant concentration is 5-15 mg/L, and the complete machine powerLess than 20 kW.

8. The method for efficiently killing water bloom microalgae and mineralized organic pollutants by using hydroxyl radicals as claimed in claim 2, wherein in the step 9), the concentration of the sodium hypochlorite mother liquor is 100-120 g/L, and the adding amount of the mother liquor is controlled to be 5-10 m³The concentration is 1.6-1.7 mg/L, and the concentration of the residual chlorine in the factory water is controlled to be 0.3 mg/L.

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