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The standard process is as follows:
Well water (tap water) → original → original water pump → sand filter → activated carbon filter → automatic softening water equipment → security filter → ultrafiltration reverse osmosis main machine → pure water tank → ozone sterilizer → centralized water point.
1. The original water tank
The device prevents the water directly extracted from the pipe network from damaging the booster pump or affecting the normal operation of the system due to insufficient flow and unstable pressure. The original water tank is built with stainless steel inlet float and liquid level sensors. Large equipment must be equipped with water inlet electric disc valve.
1) The function of float ball valve is to control the amount of raw water intake and timely water replenishment during system operation.
2) The liquid level sensor has medium water level and low water level, which is used to control the start and stop of the booster pump; When the water level of the water tank is above the middle water level, the booster pump can start automatically; When the water level of the tank is lower than the low water level, the booster pump will stop automatically.
2. The original water pump
In order to ensure the constant flow and pressure of the system water supply, the system raw water booster pump imported brand ------- Denmark Grundfs, Germany Wille, Spain Asba, maintenance free mechanical seal pump, high efficiency, low noise, stable and reliable performance. Or choose a well-known domestic brand ------ South special pump, Wuxi Jiuyang pump.
The raw water pump starts and stops automatically controlled by the water level of the original water tank.
3. Add device
Commonly used dosing pump: the United States Mitonro, the United States Pasfeida.
Coagulation ---- using iron salts, aluminum salts, polymers and other coagulants, and the impurities in the water through flocculation and bridging to generate large particles of sediment, and then through other equipment, such as clarification, filtration, etc., to be removed.
Add an appropriate amount of coagulant, effectively coagulate the colloid and organic impurities in the water, so that the above substances through flocculation and bridging action to generate large particles of sediment or flocculation, and then through pretreatment and filtration, improve the filtration effect of pretreatment, after the treatment of SDI (pollution index) ≤5. If the inlet SDI value is too large, additional coagulant AIDS should be added.
Commonly used coagulants are: aluminum sulfate, polyaluminum chloride, ferrous sulfate, ferric chloride, etc.
Commonly used coagulants are: calcium oxide, calcium hydroxide, polyacrylamide, sodium carbonate and so on.
Control: Start synchronously with the original water pump.
4. Pretreatment (also known as pretreatment)
At present, we often pretreated filter has stainless steel filter, glass fiber reinforced plastic filter and carbon steel lined with rubber filter three. Pretreatment filtration is divided into three parts: multi-medium filtration, iron and manganese removal device, activated carbon filtration and softening filtration. The United States Atuzu can be used to automatic controller according to the set time of the filter tank filter material for backwashing and forward washing; Or choose manual operation control.
Water before refining treatment, preliminary treatment in advance, in order to achieve good results in water refining treatment, improve water quality. Due to the nature of the water are a large number of impurities, such as sediment, clay, organic matter, microorganisms, mechanical impurities, the existence of these impurities, seriously affect the quality of refined water and treatment effect, so must be before the fine treatment of some impurities to reduce or remove, which requires pretreatment.
1) Multi-media filter (also known as mechanical filter)
Multi-medium filter is mainly used to remove suspended matter, sediment and granular impurities in water.
Mainly: quartz sand, anthracite, fiber ball and so on.
2) iron removal filter
RO inlet iron ion requirements: Fe2+≤ 0.1mg /L, sometimes to save costs can also be relaxed to ≤1mg/L below.
The main filler is natural manganese sand.
Principle of iron removal: oxidation method is used to oxidize low - price iron ions and low - price manganese ions into high - price iron ions and high - price manganese ions in water
3) Active carbon filter
Active carbon filter is loaded with granular water purification type active carbon, mainly to remove macromolecular organic matter, colloid, odor, residual chlorine and other impurities in the water, its strong corrosion absorption, the average can remove more than 90%. Among them, residual chlorine is a strong oxidant, which has oxidation effect on RO film and must be limited to ≤ 0.1 mg/L.
Activated carbon has round strip carbon, not shaped shell carbon and coconut shell carbon three.
4) cationic resin softener
The principle of sodium ion exchange softening treatment: the raw water through sodium type Yang, so that the hardness of the water components Ca2+, Mg2+ and resin Na2+ ion exchange, thus adsorption of water Ca2+, Mg2+, so that the water is softened.
Function: It is of positive significance to prevent surface scaling and improve the working life and treatment effect of reverse osmosis. Therefore, a softener is configured in the system. When the total hardness is less than 200mg/LCaCO3, the softener is not needed. The best control method is automatic control.
5. Add scale inhibitor device
Mechanism:
1, with anionic or non-ionic polymer to surround the colloidal particles, so that they are stable in a dispersed state, this kind of agent is called dispersant. For example: phosphate
2, the metal ions into a chelating ions or collaterals and ions, which inhibit them and anionic binding to produce precipitates, this class of agents known as chelating agents and complexing agents. Such as: EDTA
3. The colloid particles are formed into alum and suspended in water by the condensation and bridging of polymer coagulant. Such as: polyacrylamide
The main function of this device is to prevent reverse osmosis membrane scaling, the United States metering pump is used to add the agent, the dosage is accurate and the stability of the equipment is good.
Commonly used dosing pump: the United States Mitonro, the United States Pasfeida.
Commonly used scale inhibitors are: sodium hexametaphosphate, organic phosphate, polyacrylamide salt.
Control: synchronously start the same high pressure pump.
6. Fine filter (also known as security filter)
The device is mainly for reverse osmosis system water fine filtration, the purpose is to reduce or eliminate the leakage of pretreatment equipment filter material particles play a final protective role, to ensure that the final entry into the reverse osmosis system water meets the requirements.
Filtration accuracy: generally 10UM, 5UM, 1um
Fine filter (blue filter) ABS material and stainless steel material two; Blue filter has 10 "and 20", stainless steel filter has 10 ", 20 ", 30 "and 40" 5 core, 7 core, 10 core, 20 core total 16 specifications.
7. Pressure switch
Control the start and stop of the high pressure pump to prevent the high pressure pump from running in the case of lack of water and water supply, and guide the damage of the high pressure pump.
Generally, the high pressure pump can start automatically when the inlet pressure is above 1kg, and stop automatically when the inlet pressure is below 0.5kg.
8. High pressure pump
Apply a constant osmotic pressure to the reverse osmosis system.
Control: The water level of the original tank, pressure switch, regenerative micro switch, pure water level to control the automatic start and stop.
9. Water inlet solenoid valve
The main function of the device is: when the pure water tank is full or the automatic head is backwashed and regenerated, the system automatically controls the electromagnetic shutdown so as to realize the automatic stop of the system.
10. Ultrafiltration
Ultrafiltration is a pressurized membrane separation technology, that is, under a certain pressure, the small solute and through a certain pore size of the special film so that the macromolecular solute can not pass through, stay on one side of the membrane, so that the macromolecular substances have been partially purified. It is also a membrane separation process principle. Ultrafiltration uses a pressure active membrane to intercept colloid, particles and relatively high molecular weight substances in water under the action of external driving force (pressure), while water and small solute particles pass through the membrane separation process. Through the micropores on the membrane surface screening can be 3×10000 -- 1×10000 substances. When the treated water passes through the membrane surface at a certain flow rate with the help of external pressure, water molecules and solutes with molecular weight less than 300-500 pass through the membrane, while particles and macromolecules larger than the membrane pores are intercepted due to screening, so that the water can be purified. In other words, when the water through the ultrafiltration membrane, the water can contain most of the colloidal silicon removed, while removing a large number of organic matter. The principle of ultrafiltration is not complicated. In the process of ultrafiltration, concentration polarization will occur due to the continuous accumulation of the intercepted impurities on the membrane surface. When the concentration of solute on the membrane surface reaches a certain limit, the gel layer will be formed, which makes the water permeability of the membrane decrease sharply, which limits the application of ultrafiltration to a certain extent. Therefore, experimental research is needed to determine the best process and operating conditions, minimize the influence of concentration polarization, and make ultrafiltration become a reliable pretreatment method.
The key to ultrafiltration technology is membrane. Membrane has a variety of different types and specifications, can be selected according to the needs of the work. Early films were isotropic homogeneous films, that is, microporous films are now commonly used, and their pore sizes are usually 0.05mm and 0.025mm. In recent years, a number of anisotropic asymmetric ultrafiltration membranes have been produced, one of which is composed of a very thin porous "skin layer" with a certain pore size (about 0.1mm ~ 1.0mm thick) and a much thicker (about 1mm) more permeable "sponge layer" used as support. The skin layer determines the membrane selectivity, while the sponge layer increases. Because the skin layer is very thin, it is highly efficient, permeable and large, and is not easy to be blocked by solutes resulting in a decrease in flow rate. Commonly used membranes are usually made of acetate or nitrate fibers or a mixture of the two. In recent years, non-fibrous anisotropic membranes, such as membrane, polysulfone amide membrane and membrane, have been developed to meet the needs of pharmaceutical and sterilization. The membrane is stable from pH 1 to 14 and can work normally at 90 ° C. Ultrafiltration membrane is usually relatively stable, if used properly, can be used continuously for 1 ~ 2 years. Do not use temporarily, can be immersed in 1% formaldehyde solution or 0.2%NaN3 preservation. The basic performance indexes of ultrafiltration membrane are as follows: water flux [cm3/(cm2? H)]; Rejection rate (expressed as percentage %); Chemical and physical stability (including mechanical strength), etc.
11. Reverse osmosis plant (RO Membrane Technology)
1) Working principle:
Penetration ---- When two minutes of different concentrations of solutions are separated by a semi-permeable membrane, the solvent from the dilute solution will pass through the semi-permeable membrane into the concentrated solution. Reverse osmosis (reverse osmosis) ---- is a scientific method to reverse the natural osmosis process. When an external pressure is applied on the concentrated solution side that is greater than the osmotic pressure, the solvent will reverse its original osmotic direction and enter the dilute solution through the semi-permeable membrane from the concentrated solution side.
2) Water inlet requirements: turbidity ≤2 degrees water temperature: 5-35℃SDI≤5Fe≤ 0.1mg /L
PH: 4-11 Residual chlorine ≤ 0.1mg /L
3) system can adopt the world's most advanced dow membrane element, the United States can Hyde membrane element, Japan toray membrane element, the Korean film components as main components, the single membrane desalination rate of 99% or more, the system desalting rate is 97-99%, and can effectively remove the suspended solids in the water, colloid, organic matter, organic impurities such as bacteria, viruses, pyrogen, In order to ensure the stable performance and long-term operation of RO device, a timed automatic flushing device is set up.
4) The RO working pressure used in China is: ultra-low pressure film ----7-10kg, low pressure film -----15kg, high pressure film ----55kg.
5) Film material: the commonly used film is fully aromatic high cross-linking polyamide composite film (referred to as: polyamide composite film)
