Water purification information

Summary of 31 pure water treatment process problems

Update time : 2021-11-04 10:54:39

1 What pretreatment equipment do you know?

Answer: The pretreatment equipment includes: mechanical filter, high efficiency fiber filter, activated carbon filter, precision filter, ultrafiltration, microfiltration, sodium ion softener, iron and manganese removal filter, dosing device, raw water tank, aeration Gas pool.

2 What kind of pre-demineralization equipment do you know?

Answer: The pre-demineralization equipment includes electrodialysis device and reverse osmosis device.

3 What deep desalination equipment do you know?

Answer: Deep desalination equipment includes anion exchanger, cation exchanger, mixed ion exchanger, distillation device, EDI device

4 How is the mechanical filter selected? What is its working principle?

Answer: The selection of mechanical filter is based on the total water intake of the system to select the size and combination of the filter (one mechanical filter is not enough to choose multiple parallel use and the number of spares), such as water recovery according to the reverse osmosis system The ratio of the size of the rate and the water output of the system is the total water input of the system.

The packing in the mechanical filter is composed of many refined quartz sands with different particle sizes strictly according to the order from large to small, thus forming a good quartz sand gradation. When the filter is first put into use, the filtering effect is often not very good, because the filter did not form a "bridging" at the beginning. The so-called "bridging" refers to an interception net composed of suspended solids in the water, which intercepts The suspended matter with the same particle size will then intercept the suspended matter with a smaller particle size, forming an inverse particle size filtration process that first intercepts the large particulate matter and then the small particulate matter.

Once the filter forms a "bridging", the filtering effect is very good. As the time of putting into operation increases, the filtering accuracy becomes higher and the interception net becomes thicker and the inlet and outlet pressure difference becomes larger and larger. When the pressure difference reaches 1kg /cm2 The filter should be backwashed. In the process of backwashing, it is best to be equipped with compressed air to scrub the quartz sand. The general engineering experience is that the mechanical filter with a diameter of less than 2500mm does not need compressed air; and the machine with a diameter of more than 2500mm The filter must be scrubbed with compressed air to achieve a satisfactory cleaning effect; the backwash flow rate is generally 3-4 times the design capacity of the filter.

Old-fashioned mechanical filters mostly use large pebbles as the basic cushion, and the bottom is evenly punched with water-permeable holes with a convex steel plate, so that the water distribution is uneven, and it is easy to produce a large center filtration rate and a small edge filtration rate; the filter is backwashed At times, the phenomenon of mixed layer of quartz sand will occur, so that the filter material will inevitably leak into the lower pipeline and the precision filter, posing a serious threat to the precision filter and the reverse osmosis device.

After continuous practice and experimentation, many manufacturers have improved the mechanical filter. The water distribution device adopts a porous plate with a special form of ABS water cap. This ABS water cap has the function of different bidirectional output, that is, the output is small during operation. , The backwashing output can be increased several times, so that the water distribution of the filter is more even when washing, and the backwashing is more thorough, and the water quality is greatly improved.

In order to prevent fine sand from penetrating the filter during operation or backwashing, the penetration gap of this kind of ABS water cap is very small, generally about 0.1-0.2mm. It is worth noting that in the process of filling the filter filler, a certain amount of water must be injected into the filter to prevent the large quartz sand from breaking the ABS water cap; in the process of installing the water cap, you cannot wear hard shoes To prevent stepping on the ABS water cap.

The mechanical filter is equipped with a backwash water inlet limit butterfly valve to control and adjust the backwash water flow. The backwash strength should expand the filter layer by 15-25%. The backwash compressed air strength is generally 10-18L/S.m2. If there is no compressed air, consider using Roots blower.

5 How is the precision filter selected? How many ways are there for the filter element?

Answer: The selection of the precision filter is matched with the total water inflow. The diameter of the precision filter is selected according to the total water inflow. For a filter element with a filtration accuracy of 40"5um, the water output per unit is approximately 2m3/h. The types of filter elements are roughly polypropylene filter elements, honeycomb filter elements, spray-melt filter elements, pleated filter elements, etc.

6 How to remove iron in water?

Answer: The iron in groundwater is generally ferrous ferrous, so the ferrous ferrous iron must be oxidized to ferric iron. The oxidation process is completed by aeration. The aeration device fully contacts the water with oxygen to produce natural oxidation. ; The aerated water passes through the iron and manganese removal filter for iron removal process. If most of the iron in the water is trivalent iron, it does not need to be aerated and goes directly to the iron and manganese removal filter for removal.

7 Why is it necessary to add a carbon dioxide removal device after some water types pass through the cation exchanger?

Answer: As a result of the exchange of metal ions in the water with H+ ions on the cation resin, H+ ions enter the water. Therefore, the effluent of the cation exchanger is slightly acidic, so that most of the HCO3- in the water is converted into H2CO3 and further converted into CO2 gas. Due to the low solubility of CO2 gas, one is that it provides good conditions for degassing, and the other is that if degassing is not carried out, H2CO3 will be exchanged with anion exchange resin, which increases the burden of the anion exchanger and shortens the anion exchanger. The water production cycle.

Usually the CO2 removal device is placed after the cation exchanger, before the anion exchanger, or before some pre-demineralization systems such as reverse osmosis. In some places, the CO2 removal device is not required. All these depend on the user's water quality and type. Certainly.

8 How many ways are there to prevent corrosion?

Answer: There are many anti-corrosion methods such as rubber lining, epoxy, plastic lining and enamel.

9 What equipment is the reverse osmosis device mainly composed of?

Answer: The reverse osmosis device is mainly composed of high-pressure pump, high-pressure pump outlet gate valve (manual or electric), high and low pressure protection switch, inlet flow meter (or not), produced water flow meter, concentrated water flow meter, produced water conductivity meter, Membrane module (pressure vessel, reverse osmosis membrane element), concentrated water electric valve, concentrated water stop valve, inlet pressure gauge, inter-section pressure gauge, concentrated water pressure gauge, produced water pressure gauge, reverse osmosis support, reverse osmosis control panel , Reverse osmosis sampling disc, blasting membrane and corresponding pipes, clamps, elbows, etc.

10 What are the advantages and disadvantages of electrodialysis?

Answer: The advantages of electrodialysis are:

1 Low energy consumption and small floor space.

2 Simple operation and low noise.

3 The effluent quality is stable, and there is no phase change during the desalination process.

4 Pollution to the environment is small.

5 The applicable range is 200-40000mg/h.

The disadvantages of electrodialysis are:

1 Installation is more complicated.

2 The desalination effect is generally 75% if it is not complete.

3 Low water recovery rate is generally 50%.

11 What are the brands of yin and yang heterogeneous ion exchange membranes? What are their characteristics?

Answer: The yin and yang heterogeneous ion exchange membranes mainly include the Shanghai Chemical Plant Shuanghua brand heterogeneous ion exchange membrane, Lin'an heterogeneous ion exchange membrane, Beijing Shunyi heterogeneous ion exchange membrane, etc.; good quality heterogeneous ion exchange membranes must have the following Features:

1 Choose strong permeability. Selective permeability is the main indicator to measure membrane performance. It directly affects the current efficiency and desalination effect of the electrodialyzer, and its selective permeability is greater than 85%.

2 The membrane resistance is small. The electrodialyzer is composed of several hundred pairs of ion exchange membranes, so the membrane resistance occupies a large proportion in the total resistance. If the resistance is small, the operating voltage is low and the current efficiency is high.

3 Strong chemical stability. In the process of the migration of anions and cations, the concentrated water chamber will form a large concentration of ionic solution; when polarization occurs, the pH value of the retention layer on both sides of the membrane will also change, especially when the extreme water participates in the chemical reaction, it will produce oxidative extremes. Strong oxygen and chlorine, so the membrane must have strong chemical stability to extend the life of the electrodialyzer.

4 Strong mechanical strength and dimensional stability.

5 Lower diffusion performance.

6 It has a high removal effect on strong electrolytes.

12 What material is the electrode of electrodialysis made of? What are the specifications? What are the advantages and disadvantages of each?

Answer: Electrodialysis electrodes are divided into several types: titanium platinum-plated electrodes, titanium-coated ruthenium electrodes, graphite electrodes, and stainless steel electrodes; the electrodes vary according to the size of the electrodialysis body. Common engineering electrode specifications are: 800× 1600mm, 400×1600mm, 400×800mm, 340×640mm, etc.

Different electrode materials have different characteristics:

Titanium-plated platinum electrode: It has good corrosion resistance and can be used under very harsh conditions, but platinum is expensive and has fewer resources, which limits its promotion in the country.

Titanium coated ruthenium electrode: It is a compound of ruthenium (Ru), iridium (Ir), and titanium (Ti) coated on a titanium substrate, and its mixed oxide is formed after high temperature treatment; because of ruthenium (Ru), iridium (Ir), The ionic radius of titanium (Ti) is very close, and the lattice structure and space group are of the same type. Therefore, a solid solution of RuO2-IrO2-TiO2 can be formed in the co-oxidation of heat treatment. It has excellent corrosion resistance and is very suitable as an electrode material.

Graphite electrode: Graphite electrode is easily corroded, the main reasons are chemical corrosion and mechanical wear; when graphite is used as anode, due to anodic oxidation, graphite is oxidized to CO2 or CO, and its crystal structure is destroyed and damaged; in electrodialysis device The loss of middle graphite electrode is mainly caused by mechanical action. Extreme water with high flow rate has a strong scouring effect on graphite. On the other hand, the gas produced by electrode reaction has an impact on graphite. In addition, electrochemical corrosion often causes graphite. Particles flake off pollute the water quality and even block the extreme water channel; with the appearance of titanium-coated ruthenium electrodes, graphite electrodes have been gradually eliminated.

Stainless steel electrode: Generally speaking, stainless steel is only used as a cathode and cannot be used as an anode. Otherwise, because natural water contains more chloride ions, it will cause the anode of stainless steel to dissolve and generate divalent iron, nickel and chromium ions.

The correct choice of electrode material is of great significance for extending the service life of the electrode, reducing system investment and operating costs. For different water quality, electrodes of different materials can be selected:

1 For natural water with chloride as the main component, titanium-coated ruthenium electrodes are preferred.

2 For natural water with sulfate as the main component, lead plates, stainless steel, and titanium coated ruthenium electrodes are preferred.

3 For natural water with bicarbonate as the main component, stainless steel and titanium coated ruthenium electrodes are preferred.

4 For natural water with mixed ions, titanium-coated ruthenium, graphite and titanium-coated platinum electrodes are preferred.

13 How is the fresh water room, concentrated water room, and polar water room distinguished?

Answer: A cation membrane, a partition, and an anion membrane form a membrane pair. The cation membrane and the anion membrane form a water chamber. Under the action of an electric field, the ions in the water chamber move directionally. When the ions in the water chamber When leaving the water chamber through traction and selective permeability of the membrane, the water chamber is called a fresh water chamber; on the contrary, when ions enter the water chamber through traction and selective permeability of the membrane, the water chamber becomes a concentrated water chamber ; The water chamber generated between the positive membrane, the negative membrane or the separator and the electrode becomes the polar water chamber.

14 What are the parts of an electrodialysis device? What are the characteristics and functions of each part?

Answer: The electrodialysis device is composed of several parts, anion membrane, cation membrane, separator, electrode, clamping device, leak-proof rubber sheet, pickling system, flow meter, pressure gauge, ABS pipe fittings, valve, controllable Silicon rectifier cabinet.

The selective permeability of the negative and positive membranes to ions in the water enables the system to be divided into concentrated water, fresh water, and extreme water, which is the desalination part of the device.

The main material of the partition is polypropylene, which plays the role of supporting the anionic amniotic membrane and forming a concentrated fresh water chamber with it.

The electrode mainly forms the electric field required by the ion exchange membrane. The electrode is composed of a water distributor, a porous plate, and a PVC frame.

The clamping device is mainly used to fix the anion and cation exchange membranes, electrodes, separators, etc. to make them into a whole.

The leak-proof rubber sheet is between the electrode and the separator, which prevents the system from leaking water on the side of the electrode.

The pickling system is an indispensable part of the entire plant. When the electrodialysis device produces abnormal phenomena such as a decrease in the desalination rate, a decrease in water production, and an increase in operating pressure, it should be judged for what reasons the system is caused by fouling, inorganic fouling, organic fouling, etc., and corresponding chemical agents should be adopted. Perform chemical cleaning.

The thyristor rectifier cabinet is the energy feeding part of the device. It rectifies the power frequency alternating current through the thyristor rectifier device into a DC voltage with adjustable voltage. It is applied to the electrode to form a direct current electric field in the membrane stack to pull the yin and yang in the solution. The ions move in a directional direction.

The main parameters of the SCR rectifier cabinet are: rectified voltage, working current and rectified power. Flow meters, pressure gauges, ABS pipe fittings, and valves are accessories of electrodialysis, which play a role in displaying various operating parameters of the electrodialysis device, the connection of the water chamber and the switching of the water flow direction.

15 What is the desalination principle of electrodialysis?

Answer: The anion and cation exchange membrane in the electrodialysis device has selective permeability. When the ions in the solution undergo directional movement under the action of an electric field, the selective permeability of the anion and cation exchange membrane is used to permeate or not permeate the corresponding The exchange membrane forms concentrated water or fresh water in different water chambers.

16 What is the approximate distribution ratio of concentrated, light, and extreme water in electrodialysis?

Answer: The distribution ratio of concentrated water, fresh water, and extreme water in the electrodialysis device is roughly 4:4:2, so it is very meaningful to save extreme water in the electrodialysis desalination system; commonly used measures to save extreme water Part of the concentrated water is discharged after serving as extreme water or adopts extreme water circulation; the specific method of extreme water circulation system is demineralized water or desalinated water + NaCL solution as extreme water circulation.

17 How is the automatic reversal system for frequent concentrated water circulation realized? What is its significance?

Answer: In the current water treatment industry, the frequent automatic reversal of concentrated water circulation system is based on the programmable controller as the control core, the system water production process running time as the control function, and the electric or pneumatic straight-through valve and three-way valve are used for timing. Switch the flow direction of the concentrated fresh water so that the fresh water always flows into the production water tank, and the concentrated water is fixedly discharged into the concentrated water circulation tank.

In today's increasingly scarce water resources, the frequent automatic reversal system of concentrated water circulation has far-reaching significance. First, the water recovery rate of this system is as high as 80% (depending on the quality of influent water). In some large water treatment systems The effect of water saving is very obvious.

Second, the cost of the system is relatively low, and the requirements for the quality of the influent water of the system are relatively low, and it is easy to promote. force).

18 What types of pumps are needed in water treatment system engineering? How to select pumps from different manufacturers?

Answer: General pumps, booster pumps, and anti-corrosion pumps are generally required in water treatment system engineering. Ordinary pumps generally use IS-type cast iron pumps; booster pumps generally use stainless steel pumps such as Danish Granf imported high-pressure pumps (depending on specific conditions); anti-corrosion pumps generally use IH-type chemical pumps or engineering plastic water pumps.

The pump models of different manufacturers are different. First, select the flow rate of the pump according to the process requirements of the system; secondly, select the head of the pump according to the process requirements (1 kg is about 10 meters head, 1MPa is about 10 kg); again according to the process requirements Choose the material of the pump (mainly refer to the material of the pump head); finally, according to the power consumption of various pumps, choose the pump that can meet the process requirements and save the energy consumption of the system.

19 Several basic concepts in water treatment systems: TDS, SDI, LSI, KSP

answer:

TDS: Total dissolved solids (generally similar to salinity)

SDI: Pollution index is an indicator to measure the pretreatment effect of the system, SDI<6.7, for deep well water In terms of reverse osmosis equipment, the influent SDI requirement is SDI<5.

LSI: Langelier Saturation Index, Langelier index is a measure of the fouling tendency of the reverse osmosis device. LSI=0, the system has no fouling or corrosion tendency; LSI>0, the system has a fouling tendency; LSI<0, the system has a corrosion tendency. For reverse osmosis systems, the LSI value must not be greater than zero. The LSI value of the system can be reduced by adding acid, or by reducing the water recovery rate of the system.

Ksp: Solubility equilibrium constant. The reverse osmosis device selectively permeates the solvent and solute in the raw water. Concentration occurs on the concentrated water side due to the reduction of solvent. When the concentration of dissolved solids on the concentrated water side occurs because the concentration product is greater than the solubility equilibrium constant It will crystallize out and bring harm to the reverse osmosis device. Increasing the equilibrium constant of the solubility of the system can be done by adding a scale inhibitor, which can increase the solubility of dissolved solids.

20 How can the LSI index be effectively controlled?

Answer: To be able to effectively control the LSI index of the system, the following aspects can be adopted:

1 The LSI index of the system can be reduced by reducing the water recovery rate of the system.

2 The system LSI index can be lowered by adding acid.

3 The solubility of dissolved salts in the system can be increased by adding corresponding agents, such as adding TRISPE1000 scale inhibitor.

4 It is possible to reduce or pre-remove the easily structured ions in the water, such as softening the inflow of the system through a softening column.

21 What kinds of instruments and meters must be used in the reverse osmosis system?

Answer: Several instruments and meters are necessary in the reverse osmosis system:

1 Pollution index meter: used to measure the SDI index of system pretreatment.

2 Concentrated water flow meter: used to measure the flow of concentrated water in the system, and used with the produced water flow meter to determine the system recovery rate.

3 Water production flow meter: used to measure the flow of water produced by the system. Product water conductivity meter: used to measure the system water quality (conductivity)

4 Pressure gauge: measuring system inlet pressure, inter-section pressure, concentrated water pressure, and produced water pressure.

5 Water inlet flow meter: used to measure the total water inlet flow of the system.

6 Thermometer: used to measure the temperature at which the system is running.

7 Influent PH meter: used to measure the changes in the PH value of the system influent.

8 Influent conductivity meter: used to measure the conductivity of the influent water of the system, and used in conjunction with the conductivity of the product water to determine the system's desalination rate.

9 Oxidation-reduction meter: used to measure the amount of oxidizing substances in the influent water of the system to determine the degree of threat to the safety of the system.

10 High and low pressure protection switch: used to protect the system from running under low pressure (insufficient water supply) and high pressure.

A reverse osmosis system is more complicated, and the instrumentation used is determined by process requirements and user investment. A normal reverse osmosis system only needs a product water flow meter, a concentrated water flow meter, a product water conductivity meter, a pressure gauge, and high and low pressure protection.

22 What is water hammer? How to solve this problem?

Answer: The "water hammer" is caused by the air mixed in the pressure vessel, and the necessary means are not used to remove the air in the vessel when the device is started, so that the high-pressure water flow mixed with the air will cause violent vibration when moving into the vessel, which is serious. At times, the membrane element will be shattered, causing irreversible losses. "Precaution first, prevention first", how to prevent the "water hammer" phenomenon is very important. The measures generally taken are:

1 The high-pressure pump adopts the soft start method to avoid, such as step-down start, variable frequency speed control start, and series resistance start with automatic controller.

2 Avoid operation methods, such as closing or closing the inlet valve when starting, and then slowly opening the valve until the system working pressure is reached.

3 Use control to prevent avoidance, such as using PLC to control an electric slow opening door, and open the valve within tens of seconds.

4 Use the installation process to prevent, for example, set up a return pipe at the concentrated water discharge port so that the highest point of the pipe exceeds the highest pressure vessel in the reverse osmosis device, so that the pressure vessel will be full of water when the device stops running. The above points are commonly used measures in engineering applications, and can be adopted or adopted according to the actual situation. It is worth noting that the fourth point is necessary for any project.

23 Why must the reverse osmosis concentrated water discharge pipe be a little higher than the device?

Answer: The concentrated water discharge valve is always open when the reverse osmosis is running, so when the reverse osmosis device stops running, if the highest point of the discharge pipe is lower than the highest point of the pressure vessel, a "siphon" phenomenon will occur. The water will flow out of the reverse osmosis device through the concentrated water discharge pipe due to its own weight, and air is mixed in the pressure vessel. One is easy to cause water hammer, and the other is that the oxygen in the air will cause or More or less oxidation affects the service life of membrane elements.

24 What are the water intake indicators for electrodialysis and reverse osmosis?

Answer: The water inlet indicators of electrodialysis are:

Temperature range: 4-40℃, iron and manganese content: Fe≤0.3mg/l, Mn≤0.1mg/l

Turbidity: less than 0.3mg/l (for a 0.9mm thick separator) SDI is approximately equal to 0

Free chlorine: CL≤0.3mg-0.5mg/l

The water inlet indexes of reverse osmosis are: iron content: Fe≤1mg/l free chlorine: CL≤0.1mg

SDI: less than 4 temperature range: 5-45℃ turbidity: less than 1NTU

25 Mechanical filter, iron and manganese removal filter, carbon dioxide removal water inlet and outlet indicators?

Answer: The influent suspended matter of the mechanical filter is ≤20mg/l, and the effluent suspended matter is ≤5mg/l. The iron content of the influent water of the iron and manganese removal filter is ≤30mg/l, and the iron content of the effluent is ≤0.3mg/l. The carbon dioxide content of the inlet water of the carbon dioxide remover is less than or equal to 330mg/l, and the carbon dioxide content of the outlet water is less than or equal to 5mg/l.

26 What is the concentration polarization phenomenon of electrodialysis? What are the hazards of concentration polarization?

Answer: When the working current of electrodialysis exceeds the limit current, water electrolysis occurs at the interface between the anion exchange membrane and fresh water, and H+ and OH- ions are generated. Polarization occurs when these ions participate in the transfer of charge.

In short, the hazard of polarization is that a kind of electrical energy is consumed on electrolytic water that has nothing to do with desalination, which results in a waste of electrical energy. Moreover, after OH- ions enter the concentrated water chamber, CO32- and CaCO3 scale will cause membrane and electrodialysis. The performance drops.

During polarization, the concentration of electrolyte ions on the membrane surface of the desalination chamber is much lower than the concentration of the main solution, causing a very high polarization potential, while the concentration of the membrane surface of the concentrated water chamber is much higher than the concentration of the main solution, making it easy to form precipitates in the water. Ions precipitate on the membrane surface, as a result: the apparent resistance of the membrane increases significantly, the current density decreases, and the salt rejection rate decreases.

The current efficiency drops because a large part of the current is consumed in the electrolysis of water to produce H+ and OH- ions instead of the counter ions consumed to transfer the charge. If the anion membrane is polarized first, the H+ ions generated by the water dissociation of the desalination chamber will enter the concentrated water chamber through the cation membrane, making the membrane surface of the desalination chamber alkaline, and it is easy to cause Ca2+, Mg2+ ions and CO32- to form CaCO3 precipitation.

If the cation membrane is polarized first, the OH- ions produced by the hydrolysis of the desalination chamber penetrate the anion membrane and enter the concentration chamber, making the Ca2+ and Mg2+ ions blocked by the anion membrane easy to form fouling. The precipitation formed on the membrane surface is not only the increase of membrane resistance, the obvious increase of unit water and electricity consumption, and the increase of water flow resistance, but also the corrosion of the ion exchange membrane due to the change of the pH value of the solution, which shortens the service life.

27 How to control the concentration polarization phenomenon?

answer:

1 Strictly control the operating current, the electrodialysis is operated under the condition of lower than the limiting current density.

2 Strengthen the transfer process in the electrodialysis compartment, such as using a screen with good turbulence effect and high temperature electrodialysis.

3 Take regular pickling, add anti-scaling agent, switch electrodes and other measures to eliminate the precipitation caused by concentration polarization phenomenon.

4 Appropriate pretreatment can be used to improve the water quality of the system.

28 What are the characteristics of UV sterilizers?

Answer: The characteristics of the UV sterilizer are as follows:

1 Ultraviolet ray sterilization is fast, efficient and effective.

2 Ultraviolet radiation will not change the physical and chemical properties of water, and will not bring pollution to pure water as introduced by additives.

3 It can be used under various water flow rates. It is easy to operate and easy to use. It only needs to clean the quartz glass sleeve regularly.

4 Small size, light weight, low power consumption and long life.

29 What are the factors and precautions that affect the effect of UV sterilizers?

Answer: The factors that affect the sterilization effect of ultraviolet rays are the intensity of ultraviolet rays, the wavelength of the ultraviolet spectrum and the irradiation time. The matters needing attention when using the ultraviolet sterilizer are:

Installation position: The ultraviolet installation position is as close as possible to the point of use, but there should also be room for installing or pulling out the quartz tube sleeve from one end and replacing the lamp tube.

Flow rate: In the same sterilizer, when the ultraviolet radiation energy is constant and the bacterial content in the water does not change much, the amount of water flow through the sterilizer has a significant impact on the sterilization effect.

The physical and chemical properties of water: water's chromaticity, turbidity, and total iron content all absorb ultraviolet rays to varying degrees, which results in reduced sterilization effects.

Lamp power: The ignition power of the lamp has a great influence on the sterilization efficiency.

The temperature of the medium around the lamp tube: the spectral energy of the ultraviolet lamp tube radiation is related to the temperature of the lamp tube wall.

Quartz sleeve: adapt to the quality and wall thickness of the sleeve and the transmittance of ultraviolet rays, the purity of the quartz sleeve is high, and the efficiency is good.

Water layer thickness: The thickness of the water layer has a great relationship with the sterilization effect.

30 What are the characteristics of ozone sterilizers?

Answer: Ozone is one of the most effective bactericides in water treatment. Only free chlorine can compare with the bactericidal ability of ozone. The advantage of ozone disinfection is its high sterilization efficiency. Even for resistant microorganisms such as viruses and cysts, it is by far the most effective disinfectant.

It can reduce the smell, taste and color of the feed water, and the only remaining substance when it is decomposed is dissolved oxygen. In addition, the sterilization ability of ozone is not affected by changes in pH and ammonia. The use of ozone for disinfection also has its disadvantages, because electricity must be used to generate ozone, and it cannot be stored. It is difficult to adjust the amount of ozone required in time when water quality and water volume changes.

Experience has proved that ozone is most suitable for water plants with low water consumption and stable water consumption. In addition, although ozone is a strong oxidant, its oxidation ability is selective and does not generally produce oxidation. A substance that is easily oxidized like ethanol is It is not easy to interact with ozone.

31 What problems should be paid attention to in water sample collection in water quality analysis?

Answer: The following issues should be paid attention to in water sample collection in water quality analysis:

Sampling should be representative, that is, the water sample taken can represent the water quality of the entire water body.

The water quality of the water sample should be stable or not changed significantly between the use and analysis. The sampling volume should be 4-5 times of the required sample volume of the test item to ensure the water sample volume for repeated analysis and retesting. The minimum sampling volume should be subject to the requirements for ensuring the accuracy and precision of the analysis.

Try to shorten the contact time between the water sample and the sampling equipment. The water sample should flow through the pipeline at a high linear flow rate. The cleaning requirements should be consistent with the container used.

For on-site test items, such as PH value, dissolved oxygen, alkalinity, CO2, ferrous iron, ammonia nitrogen, residual chlorine, etc., the time interval between sampling and analysis should be shortened as much as possible, and online analysis and detection should be used as much as possible.

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