Forward osmosis (FO) is a novel membrane process that potentially can be used as an
energy-saving alternative to conventional membrane processes. The objective of this
study is to investigate the performance of a FO membrane to draw water from
wastewater using seawater as draw solution. A study on a novel osmotic sequential
batch reactor (OsSBR) was explored. In this system, a plate and frame FO cell
including two flat-sheet FO membranes was submerged in a bioreactor treating the
wastewater. We found it feasible to treat the wastewater by the OsSBR process. The
DOC removal rate was 98.55%. Total nitrogen removal was 62.4% with nitrate,
nitrite and ammonium removals of 58.4%, 96.2% and 88.4% respectively. Phosphate
removal was almost 100%. In this OsSBR system, the 15-hour average flux for a
virgin membrane with air scouring is 3.103 LMH. After operation of 3 months, the
average flux of a fouled membrane is 2.390 LMH with air scouring (23% flux
decline). Air scouring can help to remove the loose foulants on the active layer, thus
helping to maintain the flux. Cleaning of the FO membrane fouled in the active layer
was probably not effective under the conditions of immersing the membrane in the
bioreactor. LC-OCD results show that the FO membrane has a very good performance
in rejecting biopolymers, humics and building blocks, but a limited ability in rejecting
low molecular weight neutrals.
| Date of Award | Jul 2011 |
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| Original language | English (US) |
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| Awarding Institution | - Biological, Environmental Sciences and Engineering
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| Supervisor | Gary Amy (Supervisor) |
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