Some Misunderstandings about Membrane

Many people have quite a few misunderstandings about membrane, we hereby make explanations to these common misconceptions, let’s check if you have some!

Misunderstanding 1: Membrane water treatment system is difficult to operate

The automatic control requirement of membrane water treatment system is much higher than that of conventional biochemical treatment system. Many users mistakenly believe that membrane water treatment system is difficult to operate.

In fact, the operation of membrane water treatment system is highly automatic, and the operation of start and stop, dosing and online washing are all carried out by the PLC system program control. It can be unattended, only manual regular inspection and dispensing, periodic maintenance and cleaning are needed, and basically no additional operating staff is needed.

Routine cleaning and maintenance of membrane can be mastered in one day of training, which is far less difficult than biochemical system which requires higher comprehensive skills of employees.

Misunderstanding 2: High investment, cannot afford to use

Some people think that the one-time investment and membrane replacing cost is very high, so they cannot afford to use. In fact, with the rapid development of domestic membrane suppliers, the price of membrane is constantly decreasing.

Using MBR membrane system can save the cost of civil construction and land, reduce the amount of sludge and sludge disposal costs, it’s cost-effective and is a good choice. For UF membrane and RO system, the economic benefits generated by the realization of wastewater recycling are far more than the investment in the equipment.

Misunderstanding 3: Membrane is fragile and easy to break

Due to lack of experience, the membrane systems designed and constructed by some engineering companies have problems of fiber breaking and module scrapping etc., and users mistakenly believe that membrane products are difficult to maintain. In fact, the problem is mainly from the process design and membrane system operation experience.

With reasonable pre-treatment design and safety protection design, the high-quality reinforced PVDF membrane can be used for an average of more than 5 years, when it is used in combination with RO membrane, the service life of RO membrane can be effectively extended.

Misunderstanding 4: The brand/quantity of membrane is more important than membrane system design

When some enterprises establish membrane system, they pay too much attention to imported brands, and lack understanding of the importance of system design.

Nowadays, the performance of some domestic ultrafiltration membrane has reached or even exceeded the international advanced level, the cost performance ratio is much higher than imported membranes. In practical cases, the membrane system problems come more from engineering design.

When UF+RO or MBR+RO process is adopted, the poor operation of the RO system is often related to the insufficient area of the pre-treated MBR or UF membrane or the unreasonable design, resulting in the excessive inlet water quality of RO system.

Misunderstanding 5: Membrane technology is omnipotent

Membrane process has the characteristics of low turbidity of effluent, decolorization, desalination and softening, etc. However, in the treatment of industrial wastewater, membrane technology usually needs to be combined with traditional physicochemical and biochemical treatment processes, so as to better play the advantages of membrane advanced treatment.

Moreover, membrane water treatment usually has the problem of concentrated water discharge, and it also needs support from other technologies, so it is not omnipotent.

Misunderstanding 6: The more membrane, the better

In a certain range, increasing the number of membranes can improve the water production security of membrane system and reduce the operating cost.

However, when the number of membrane increases above the optimal value, the average amount of water spread on the unit membrane decreases, and the flow velocity of the cross-flow filtered water is lower than the critical value, the impurities on membrane surface cannot be taken away, which results in increasing pollution and blockage of membrane, and the water production performance decreases.

In addition, if number of membrane increases, the amount of washing water will increase. If washing pump and amount of compressed air cannot meet the requirement of the amount of washing water per unit membrane area, it will be difficult to wash thoroughly, membrane pollution increases, and water production performance is affected, which is particularly important for MBR or UF membranes.

Besides, when number of membrane increases, the one-time investment and depreciation cost of membrane system will also increase.