Analysis of Operation Failure of Reverse Osmosis System

Failures caused by the worse feed water quality

In the initial design, the Reverse Osmosis System operation was relatively stable due to the good feed water quality, but with the subsequent deterioration of the feed water quality, when the system could not be optimized and improved in pretreatment, the serious operating failures will be occured. The specific performance is that the permeate water capacity decrease rapidly, while the running pressure increase rapidly.

Failures caused by the performance degradation

Due to the deterioration of the performance of the pretreatment filters, the turbidity, SDI value and COD value of the effluent seriously exceed the requirements of the feed water quality. The specific manifestations are: CMF or UF membrane filament breakage; serious bacterial and microbial reproduction in buffer water tank; multi-media filter filter material turbulent layer or bias flow; activated carbon filter filter material powder or serious microbial reproduction.

Failures caused by the use of inferior filter elements in the cartridge filter

When the flow of the cartridge filter increases, the filter element is easily deformed or the filtration accuracy cannot meet the requirements, so that the pollutants directly enter the Reverse Osmosis System. The specific manifestations are: the diameter of the filter element of the cartridge filter is too small; the quality of the filter element is bad, and the filtration accuracy cannot meet the requirements; the filter element is not pressed tightly and easily deformed.

Failures caused by improper selection and dosing of antiscalant

As the "protector" of the safe and stable operation of reverse osmosis system, antiscalants have become the mainstream of the current form of scale inhibition due to their excellent effects and low operating costs. question. The specific manifestations are: the performance of the antiscalant does not match the water quality; the performance of the antiscalant dosing pump is unreliable; the excessive dilution of the antiscalant; the antiscalant dosing tank is seriously polluted.

Failures caused by improper dosing of other chemicals

According to different water quality, it is necessary to add a certain amount and type of chemicals to increase the treatment effect of raw water. However, due to various reasons, the incorrect use and dosing of these chemicals may have serious consequences. The specific manifestations are: unsuitable flocculants bring serious membrane fouling; excessive dosage of oxidant causes membrane oxidation; excessive dosage of reducing agent causes serious fouling of the membrane.

Failures caused by instrumentation failure

At present, imported digital display instruments are generally used in reverse osmosis system. Under the premise of correct installation, some instruments can display very accurate flow and have stable readings; but other types of digital display instruments have relatively large fluctuations in value during operation, especially Some instruments have the function of parameter setting, and the displayed water production is controlled by human factors, so the instrument acting as the eyes of reverse osmosis will affect the judgment of technicians on reverse osmosis. The specific performance is as follows: 1. The concentrated water flow rate is too large (actually smaller), which causes the reverse osmosis recovery rate to be too high to cause scaling; 2. The concentrated water flow rate shows too small (actually larger), which causes the reverse osmosis recovery rate to be too low to generate pressure. 3. The fluctuation of the flow meter reading is too large, and it cannot be judged correctly according to the ratio of 10 to 15%.

Failures caused by improper operation and maintenance

There are many problems in reverse osmosis system, some systems have defects in design, and some have partial deviations in the daily operation and maintenance process, causing serious hidden dangers in operation. The specific manifestations are: 1. In the initial design, the head selection of the high-pressure pump was low, and the water production volume did not meet the design requirements when the temperature or influent water quality changed; 2. The membrane element was oxidized to cause an increase in water flux and production. Water quality decline; 3. The actual recovery rate is too high due to the inversion or damage of the brine sealing ring, resulting in scaling and water quality decline; 4. The O-ring damage causes the water quality to decline; 5. New and old membrane elements, different types of membrane elements Mixed use causes the system performance to decline; 6. The concentrated water thrust ring of the pressure vessel overlaps or partially overlaps with the concentrated water outlet, causing the recovery rate to be too high and causing scaling; 7. The length of the pressure vessel is too large, causing the concentrated water to leak to the water production side The quality of the permeate water is degraded; 8. The non-segment pressure gauge cannot reliably analyze and judge the operation of the reverse osmosis; 9. The larger pressure difference causes the membrane element to produce a telescope effect and damage; 10. The increase of the permeate back pressure causes the production 11. The unreasonable arrangement of reverse osmosis causes the water flux of local membrane elements to increase and the pollution rate to accelerate; 12. The design of reverse osmosis recovery rate is unreasonable, and the number of membrane elements is too small; 13. Particulate pollution makes membrane elements produce relatively Serious mechanical fouling, large pressure difference in the first section, and poor water production and water quality; 14. Pollutant deposition and bacterial and microbial contamination caused by system shutdown.

More inquiries related to Reverse Osmosis System please contact:

Mob& Wechat& WhatsApp: (+86)13544774483

Email: sales010@water-sy.com

We will provide high-quality, all-round comprehensive professional services for project consulting, system design, manufacturing, installation and commissioning, personnel training, etc