Membrane autopsy is defined as ‘an Excellent tool or technique to understand and diagnose the problem related to fouling, scaling, salt passage flow, flux, and pressure difference across the sides.’ However, with our vast experience in such autopsies, we understood that the Autopsy technique has its meaning, way beyond the above-mentioned definition.
It is actually a silent communication between a technician who is doing an autopsy and the membrane. The membrane tells you a lot about its hardship and the treatment it has gone through, and we need to listen, feel, and understand this membrane’s communication. Once you establish this bond with the membrane, you can understand and define a remedial action to rectify various operational errors and improvements.
Based on our experience, we broadly categorize membrane failures as follows :
1. Reversible damage.
2. Irreversible damage.
During our various interactions with system users, we understood that the user’s point of view towards Membrane Autopsy is nothing but just opening of membranes and analyzing the fouling. They feel that with this analysis, they can use some cleaning techniques, and the damage to membranes can be reversed.
What we believe is that fouling, scaling of Ca, Mg, and mild deposition of metals contribute to reversible damage up to 90%. In this deposition, calcium and Magnesium can be removed smoothly and easily. Here, we have to accept that with every cleaning, the membrane deteriorates slightly. The percentage of deterioration may vary from system to system.
But sometimes, the membrane gets irreversible damage, and the causes for irreversible damage are mostly hidden in improper operational methods and flaws, and errors in system design. These improper operational practices and high expectations from the membranes while designing may give such permanent or irreversible damage.
During Autopsy, we get information about various types of operational damages and other damages such as Hydrolysis, Panic cleaning/Harsh cleaning, back pressure spiking, hammering, oxidants, and fouling or residual of organic compounds, etc, where the membrane had suffered a lot.
In general, industry speaks more about the reversible damages due to scaling, deposition, and fouling, but Autopsy is a more effective tool to understand irreversible damages, also some of those mentioned above, which allows the system owner to improve system operations and eliminate the errors. This information is also useful and vital for system designers.
Apart from Effluent treatment plants, in Raw water treatment plants, we have seen severe damage due to organic chemical fouling. Nowadays, the number of so-called ‘freshwater sources’ is getting polluted and this is definitely going to impact the membrane’s life. This pollution, even in minor quantities, can create irreversible damage to the membranes. Organic fouling or chemical fouling is are hidden threat to the membrane. In a few of the cases, the attack due to the pollutant in raw water on the membrane was so scary that we were speechless. The attack of organic compounds on the membrane is a vast subject in itself.
Autopsy is all about such a special technique of silent communication and minute observations.
A well-performed Autopsy gives all probable causes of membrane failure and guides us for remedial actions to rectify the problem and avoid it in the future.
In Vipanan, we are trying to focus more on the irreversible damages. Reversible damages due to Calcium and Magnesium Deposits and fouling can be removed by cleaning chemicals and other tools effectively. But what about the irreversible damage that happened to membranes?
So many times, the membrane surprises us and tries to communicate so many things and problems due to water chemistry and operational practices. But to analyse this, we need to learn this special technique of silently understanding what the membrane is telling or showing us. With this blending of communication and minute observation technique, we need to interpret the problems, define them, and diagnose or define remedial action.
The Autopsy is a very effective tool; if used periodically, we can enhance the membrane system’s life. It’s similar to a quarterly or annual medical check-up, which we do with our bodies. An autopsy is a medical check-up of the system to retain and maintain its life. The only requisite is that you need a qualified and experienced doctor to perform such tests.
Quick Facts: Membrane Communication
- Membranes don’t fail suddenly—most failures are the result of gradual fouling, scaling, or chemical attack that can be detected early.
- A pressure increase of just 0.5 bar across a membrane may indicate fouling or clogging.
- Declining salt rejection percentages can silently point to chemical degradation or cracks in the membrane structure.
- Silent indicators like temperature differences or uneven flow distribution often reveal operational inefficiencies.
- Autopsy studies show that more than 70% of unexpected RO system failures could have been prevented if early “membrane signals” had been acted upon.
After defining remedial action and rectifying the problem, the membrane system will be happy and ready to perform the way it was designed. And if the membrane system is happy, then the user is happy and gets value for its heavy investment.
Hence, we at Vipanan say that to do an effective autopsy, one should be an effective observer and should be able to communicate silently with the membrane.