AWWA MTC69787

This powerpoint presentation begins by providing a brief overview of a reverse osmosis (RO) bench-scale unit and short/long term hydraulic performances. Membrane autopsy, chemical characterization, and bacteria and phytoplankton characterization are presented. Presentation objective is to develop and validate methods for a RO desalination membrane.Dominant groups were identified by sequencing of 16S rRNA genes,and specific DNA probes will be designed.Diversity changes over the membrane surface were monitored byfingerprinting of 16S rRNA genes (SSCP analysis). The dominant organisms responsible for fouling will be enumeratedby fluorescent in situ hybridization techniques using specific probesand confocal microscopy. Topics presented include: bacterial diversity and activity; membrane autopsy protocol; methods used to extract nucleic acids priorto PCR amplification; membrane DNA/RNA Extraction and16S PCR amplification; effect of DNA extraction method on bacterialdiversity as monitored by SSCP analysis; and, analysis of bacterial diversity by fluorescent insitu hybridization (CARD-FISH). Presentation conclusions indicate: no significant decrease of RO hydraulic performances,but presence of foulants on RO membranes, mainly bacteria, aluminosilicatesand organics (proteins and carbohydrates);additional resistance negligible in comparison with the intrinsicmembrane resistance;for long term operation, the biofilm growth provide significant additionalresistance due to the decrease in the cake porosity;DNA/RNA extraction methods were satisfactory;first in situ hybridization trial using a general probe on fouled membranesrevealed distinct cell morphologies and many clusters of bacteria; and,the enumeration of cells might be difficult due to the intrinsic irregularity ofmembrane surface. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

21

File Size:

1 file , 1.9 MB