Membrane Autopsy - Unique and silent communication with membranes...!
Membrane autopsy is defined as, ‘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 Autopsy technique has it’s meaning, way beyond the above-mentioned definition.
It is actually a silent communication between a technician who is doing autopsy and the membrane. The membrane tells you a lot about it’s 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 membrane then 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 user’s point of view towards Membrane Autopsy is nothing but just opening of membranes and analyse 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 of Calcium and Magnesium can be removed smoothly and easily. Here, we have to accept that with every cleaning, membrane deteriorates slightly. Percentage of deterioration may vary from system to system.
But sometimes, 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 expectation from the membranes while designing may give such permanent or irreversible damages.
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. etc. where 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 them mentioned above) that gives system owner an opportunity 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 also, we have seen sever damages due to organic chemical fouling. Now-a-days, number of so called 'fresh water sources' are getting polluted and this is definitely going to impact the membrane's life. This pollution, even with minor quantity can create irreversible damages to the membranes. Organic fouling or chemical fouling are hidden threat to the membrane. In few of the cases the attack due to the pollutant in raw water on membrane was so scary that we were speechless. Attack of organic compounds on membrane is vast subject in itself.
Autopsy is all about such 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 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 damages 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 membrane is telling or showing us. With this blending of communication and minute observation technique, we need to interpret the problems, define it and diagnose or define remedial action.
The Autopsy is very effective tool, if used; periodically we can enhance membrane system's life. It’s similar to a quarterly or annual medical check-up which we do with our body. Autopsy is a medical check-up of the system to retain and maintain it’s life. The only requisite is you need a qualified and experience doctor to perform such tests.
After defining remedial action and rectifying the problem, membrane system will be happy and ready to perform the way it was designed for. And if the membrane system is happy then the user is happy and gets value for it’s heavy investment.
Hence, we at Vipanan, say that, to do effective autopsy, one should be an effective observer and should be able to communicate silently with the membrane.