Large Automotive manufacturer in India was operating traditional ETP (Effluent Treatment Plant) with UF (Ultra Filtration) and RO (Reverse Osomosis), for treated water recycling since 5 years.
Last year, they modified their effluent treatment plant and adopted MBR (Membrane Bioreactors) based treatement. Naturally, being latest trend they were expecting better performance and lesser footprint.
But, to there surprise after this modification, RO system did not gave expected or better performance which was reflected to the replacement of the membrane, costly down time. A shorter life of membrane was a question and this resulted in panic situation……
This Automotive giant approached us with their problems and we suggested them to do RO Membrane Autopsy. Based on our recommendation, they selected the RO membrane for autopsy and sent it to us with recommended packing. We studied this case and came up with very interesting facts.
So, this blog is about this case and findings
The principle Effluent treatment flow diagram is as follows :
Chemical used for Effluent treatment are :
1. Ferric Chloride
2. Lime
3. Flocculant
4. Chlorine
Chemical used for RO feed treatment :
1. SMBS
2. Antiscalant
All these chemicals were common and standard chemicals available in market.
After receipt of membrane while carrying out autopsy we came up with very valuable observations and findings as follows :
Fiberglass cover damaged
Compression observed
Delamination observed
Mild blister formation
Chemical fouling observed
Each of the above picture reveals some situation and understandng of this condition and exact interpretation is necessary
Some of our analytical findings and interpretation of foulants deposited on membrane leaf are as follows :
1. The chemical analysis revealed more deposition of calcium, silica, magnesium and heavy metals like copper,
chromium, iron and cobalt .
2. Microbiological deposition was very less.
3. Fujiwara test and Dye test were positive at various locations.
Although MBR have been introduced, traces of coagulant prominently observed on a membrane which was due to uncontrolled dosages of flocculant and coagulant or inadequate settling time. Also, due to heavy metal contamination found, the question arises ; Is it worth switchng to MBR to reduce the footfrints of plant if it is going to affect RO feed quality in terms of heavy metals ???????
So, RO Membrnae Autopsy gives a very valuable inputs to plant designers and plant operators on ‘what should be a correct approach in such modifications or adoption of MBR’ With this study costly down time, replacement of membranes and future panic situation can be avoided.