Cleaning of the reverse osmosis system
The cleaning effect of the reverse osmosis system is related to the selection of the appropriate reverse osmosis film cleaning agent and the correct reverse osmosis film cleaning method.During the first cleaning of the reverse osmosis system, it is recommended to contact the equipment manufacturer, RO membrane component manufacturer, and RO system special agent supplier.Once the type of pollutant is identified, it is recommended to use one or more cleaning agents and select a supplier of reverse osmosis agents that can provide and have water treatment technical services.
If the desired effect is not achieved by cleaning, consider contact and communication with those companies that can provide technical services.Remove one or two membrane elements from the front or back end of the system and send them to the company that provides technical services to allow the partner to determine the optimum cleaning steps while reporting the RO system flow and desalination effect after cleaning.
1, calcium carbonate scale.
2, calcium sulfate, barium sulfate, strontium sulfate scale.
3, Metal oxides of iron, manganese, aluminum, etc.
4, silica.
5, colloidal sediment, oil stain (inorganic or inorganic ~ organic mixture).
6, is a natural or synthetic organic matter.
7, biomass (biological sludge, mold, or fungi).
reverse osmosis systems are usually cleaned by online cleaning and offline cleaning.
The advantage of online cleaning method is that without removal of membrane elements, simply transport the membrane cleaning agent to the cleaning site; the disadvantage is that due to the conditions of operation equipment, online cleaning is to clean the dirt through a single chemical effect on the original operation equipment, the contamination of each membrane is different, and the cleaning effect cannot be treated differently during cleaning.
Offline cleaning is to remove the reverse osmosis membrane from the system using professional cleaning equipment for cleaning, through physical and chemical cleaning purpose to achieve the help of the physical characteristics of special film cleaning equipment, plus the chemical assistance to make the cleaning is very thorough, and almost no damage to the film.
Therefore, it is generally recommended that systems with light pollution or initial cleaning should first resume with online cleaning. If it is difficult to return to normal operation after online cleaning, offline cleaning is thoroughly adopted, and the performance parameters of single membrane elements can be tested, screened and evaluated.
When the following pollution characteristics appear: 10 ~, 15%, 10 ~, 15%, or the pressure drop between feed and concentrated water increases by 10 ~, 15%, the RO system needs to be cleaned.
The frequency of cleaning because RO system appears dirt varies by case, generally customary acceptable cleaning frequency is 3~12 months cleaning.If you have to be cleaned once or more a month, you should focus on improving the RO preprocessing system and adjust the operation parameters of the RO system; if cleaning is required every 3 months, you need to improve the operating level of the current equipment, but whether the preprocessing system will be further judged.
It is usually necessary to be cleaned with a variety of different cleaning drugs in a specific order for optimal cleaning results.We first used a detergent with low pH to remove the scale class of substances, and then a high pH detergent was used to remove the organic matter.Sometimes oil dirt is first removed with a high pH cleaner, and then a low pH cleaner is used.Some membrane cleaners have been added with detergent, which will help in the removal of severely contaminated biological and organic impurities.There are also some membrane cleaners that add chelators such as EDTA that help in the removal of colloids, organic matter, biological impurities, and sulfate scale.It must be remembered that choosing incorrect cleaning agents or incorrect cleaning steps may cause worse congestion.
Mechanical cleaning prior to 1, chemical cleaning.
The 2, detergent spreads to the dirt surface.
3, penetrates into the dirt layer.
4, cleaning reaction: which includes materialized fication process: dissolution, mechanical stress and thermal stress, wetting, soaking, swelling, contraction, solvation, emulsification, anti-flocculation and adsorption.The chemical processes are: hydrolysis, glue dissolution, saponification, dissolution, integration, integration and suspension. These reactions always generate some soluble products and at least disperse some substances.The reaction product attenuated the binding force between the dirt particles and the membrane surface.
The 5, cleaning reaction products were transferred to the inner surface.
1, prepares the cleaning agent in the chemical cleaning box according to the product instructions of the membrane cleaning agent, and mix evenly to control the pH value and temperature.
2, reduces the level within the membrane pool to a minimum or emptying water in the membrane pool.
3, As a reverse wash manner, the chemical detergent reverse penetrates the membrane from the inside of the hollow fiber under the pressure of the cleaning fluid pump and accumulates in the membrane pool until the membrane assembly is submerged.
4, allows the cleaning agent to soak the membrane filament in the membrane pool for 2 ~ for 4 hours, which can be exposed to enhance the cleaning effect.
5, was first alkali washed, acid washed and finally with oxidant solution.
6, During the cleaning process, observe the membrane cleaning agent pH changes at any time, and add an appropriate dosage according to the change to meet the pH value requirements in the cleaning protocol.When the pH value of the film cleaning agent pH changes greatly and the film cleaner is dirty, the film cleaner should be replaced in time.
7, Improve the cleaning agent temperature can enhance the cleaning effect, the cleaning agent temperature shall not exceed 40℃.
8, After each chemical cleaning, drain the medicine liquid in the film tank and medicine washing tank, add pure water or ultrafiltration production water to the medicine washing tank, open the cleaning pump, reverse rinse the system, generally 2~3 times, until the cleaning fluid and contaminants in the system are washed clean (detergent pH is neutral).
The 9, recommends a dilution ratio of 1~3% (1:45) of the entire osmosis cleaning system (tank, connection pipe, filter, pressure vessel, membrane) volume, which can be determined based on production tests.
10, recommends that acid detergent dilution run a pH of 2.0~3.0 and alkaline detergent dilution of 10.0~11.5.
11, If microbial contamination occurs in the system, there should be another fungicide added after cleaning.fungicide may be added immediately after cleaning or regularly (like once a week) or continuously to the system during operation.It must be ensured that the fungicides and membrane originals are compatible, do not affect health, can effectively control biological activity, and the costs will not be too high.
1, complies with the manufacturer's recommended drug selection list, dose, pH, temperature, and contact time.
2, completes the cleaning with minimal aggressive membrane cleaning agents, which extend the life of the membrane.
3, must be careful to extend the service life of the membrane when regulating the pH value.The pH values with less drug erosion range from 4 to 10 and the maximum allowed pH range is 2 to 12.
Do not mix the 4, acid and base.The system was washed thoroughly to drain the previous cleaning solution before adding the next solution.
5, should be washed sed the detergent with high pH, otherwise there is residue.
6, confirms compliance with the correct membrane detergent treatment requirements.
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