The main objective of this study was to investigate the influence of the feed solution
chemical composition on the performance and fouling, both biofouling and abiotic
fouling, of various reverse osmosis (RO) and nanofiltration (NF) membranes. Fouling experiments were performed as a factorial design with four
independent variables: divalent cation concentration, monovalent cation concentration,
dissolved organic carbon (DOC) concentration and membrane type denoted by
Molecule Weight Cut-Off (MWCO) and roughness, each with three levels to produce
a 34 factorial design.
The membranes tested were the following: TFC-S (Koch Membrane Systems, San
Diego, CA) with MWCO of 200Da and the roughness of 35.64nm; 4040-UHA-
ESPA (Hydranautics, San Diego, CA) with MWCO of 100-300Da and the roughness
of 78.39nm; and, NTR 7450 (Hydranautics, San Diego, CA) with MWCO of 500Da
and the roughness of 27.84nm. These were run at pressures of 280 psi, 120 psi, and
120 psi, respectively. Experiments were conducted using a flat sheet test unit (Osmonics, Minneetonka,
MN), which contained a cell with 155cm2 active membrane area. Feed water was
pumped into the test unit from feed reservoir, and all the concentrate flux was
recycled to the feed tank to increase the fouling potential on the membranes. New
membranes were rinsed with deionized (DI) water, then soaked membrane-skin-down
in DI water overnight, and rinsed again immediately
before installation into the filtration cell unit.
Abiotic fouling and biofouling tests on the fouled membrane were also conducted to
characterize the fouling on the membrane after each experiment. The membrane
specimens were soaked in a basic (0.1M NaOH) solution overnight and then UV254
and turbidity were measured to characterize the abiotic fouling of the membrane.
Biofouling of the membrane was measured by detaching the biofilm from the
membrane surface and measuring the heterotrophic plate counts (HPC). Includes 9 references, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 280 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 6 |
| Published : | 06/16/2002 |
