Membrane Autopsy Service Capabilities
Each membrane element that is autopsied is thoroughly inspected for any type of abnormality. Every membrane is subjected to integrity testing, which detects everything from small mechanical leaks to severe damage. The exterior of the membrane is then thoroughly examined for cracks and any other sign of damage that may have occurred during operation. The element is then dissected and fully examined by a Hydrovida specialist. Flat sheet material is harvested for cell test analysis, damage analysis and foulant analysis.
Full Element Wet Test
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Each element is wet tested to gain insight on overall performance parameters. The permeate product flux, overall rejection and differential pressures are obtained and compared to the manufacturer's published specifications. Initial element performance gives several clues as to why the membrane element may be failing. Integrity testing is also performed on the element to determine if any physical structural damages (e.g. tears, delamination, broken components) are present within the RO membrane.
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Comprehensive Element Inspection
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A thorough, external and internal inspection is performed on the element. The element is examined for any physical or mechanical defects or damages that would be detrimental to its performance. In the external inspection, the fiberglass casing and brine seal are examined for cracks or tears. The Anti-Telescoping Devices (ATDs) are examined for cracks or breaks or signs of excessive pressure or abnormal running conditions. The element is then dissected and the internal components are analyzed and inspected for abnormalities, fouling and damage. The scroll ends, membrane surfaces, feed spacers, glue lines, permeate spacers and membrane backing are all examined and sampled for analysis.
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Foulant Analysis
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After the element has been dissected and analyzed for physical damage and defects, samples of deposited foulant and flat sheet material are removed for analysis. Hydrovida uses state-of-the-art analytical equipment including Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FT-IR), light microscope analysis, stereoscope analysis, Gas Chromatography-Mass Spectrometry (GC-MS) and Element Mapping techniques to help determine the precise composition of fouling or damage that occurs to a membrane. Between the combination of all these analytical techniques, Hydrovida can identify virtually any unknown substance present in a sample.
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Cleaning Study
Image of pre clean (outside) and post clean (inside) of harvested membrane flat sheet in cell tester
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Flat sheet samples that are harvested from the dissected element are set in a cell test apparatus and subjected to the manufacturer's tested conditions to test overall flux and salt passage. The flat sheets are then cleaned with a variety of different Hydrovida membrane cleaners to determine the most effective cleaning regimen specific to the type of fouling observed.
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Testing for Membrane Damage
Fujiwara (chlorine testing) on flat sheet membrane. Positive test (left) and negative test (right)
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Harvested membrane flat sheet samples are tested for halogen (chlorine) oxidation, pH hydrolysis and other types of physical or chemical damage. Dye testing can be performed on the flat sheet samples to determine the severity of damage to the salt rejecting polyamide surfaces. In addition, irreversible physical damage that occurs during improper operation of a system, such as compaction or delamination is also assessed on the membrane samples.
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