How to clean the reverse osmosis membrane components of pure water equipment?

How to clean the reverse osmosis membrane components of pure water equipment?

No matter what kind of mechanical equipment we use, what is most troublesome for us is cleaning. If it is not cleaned, it will cause pollution and will pose a threat to our health. Pure water equipment Reverse osmosis membrane elements are contaminated by suspended solids or insoluble salts that may be present in the water. The most common of these pollutions are calcium carbonate precipitation, calcium sulfate precipitation, and metals (iron, manganese, copper, nickel, aluminum). Such as oxide precipitation, silicon deposits, inorganic or organic deposition mixtures, NOM natural organic substances, synthetic organics (such as: scale inhibitors / dispersants, cationic polyelectrolytes), microorganisms (algae, mold, fungi) and other pollution.

The nature of the pollution and the rate of contamination depend on various factors such as feedwater quality and system recovery. Usually pollution is progressive, and if not controlled as early as possible, the contamination will damage the membrane elements in a relatively short period of time. Membrane components are recommended to be cleaned when the membrane element is confirmed to be contaminated, or before a long-term shutdown, or as a routine routine maintenance.

Chemical cleaning or physical washing is required when the following conditions are present in the reverse osmosis system (or device) of the purified water equipment:

1. Under the normal water supply pressure, the water production is 10-15% lower than the normal value.

2. In order to maintain normal water production, the temperature corrected water supply pressure is increased by 10 to 15%.

3. The water quality of the produced water is reduced by 10 to 15%, the salt permeability is increased by 10 to 15%, and the water supply pressure is increased by 10 to 15%.

4. The pressure difference between the various sections of the system increases significantly.

Maintaining stable operating parameters mainly refers to water production flow, water production back pressure, recovery rate, temperature and TDS. If these operating parameters fluctuate, it is recommended to check for contamination, or whether the actual operation of reverse osmosis is normal under the premise of changes in critical operating parameters.

The overall performance of the timing monitoring system is the basic method to confirm whether the membrane element has been contaminated. The effect of contamination on membrane elements is gradual and the extent of the impact depends on the nature of the contamination. Table 1 "Reverse Osmosis Membrane Pollution Characteristics and Treatment Methods" lists common pollution phenomena and corresponding treatment methods. The cleaning cycle of the contaminated reverse osmosis membrane depends on the actual situation on site. The normal cleaning cycle is once every 3-12 months.

When the membrane element is only slightly contaminated, it is important to clean the membrane element. Severe pollution can hinder the cleaning effect by hindering the penetration of chemicals into the contaminated layer.

What kind of contaminants are cleaned and how they are cleaned should be done according to the site contamination. For the complicated situation where several kinds of pollution exist at the same time, the cleaning method is to alternately clean with a low pH and high pH cleaning solution (high PH value should be cleaned first after low pH).