Hybrid SBR-FO system for wastewater treatment and reuse

Operation, fouling and cleaning

Journal article (2016)

Authors

R. Valladares Linares King Abdullah University of Science and Technology, BT/Environmental Biotechnology - AS
Zhenyu Li John F. Kennedy School of Government
Qingyu Li King Abdullah University of Science and Technology
J.S. Vrouwenvelder BT/Environmental Biotechnology - AS , King Abdullah University of Science and Technology, Wetsus, European Centre of Excellence for Sustainable Water Technology
Gary L. Amy King Abdullah University of Science and Technology
Noreddine Ghaffour King Abdullah University of Science and Technology
Research Group
BT/Environmental Biotechnology (AS) (TU Delft)
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Published Date

2016

Language

English

Reuse Rights

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Faculty

Applied Sciences

Department

BT/Biotechnologie

Research Group

BT/Environmental Biotechnology

Abstract

Forward osmosis (FO) is a novel membrane separation process that potentially can be used as an energy-saving alternative to conventional membrane processes. A hybrid sequential batch reactor (SBR)-FO process was explored. In this system, a plate and frame FO cell including two flat-sheet FO membranes was submerged in a bioreactor treating synthetic domestic wastewater. The dissolved organic carbon (DOC) removal efficiency of the system 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%. The 15-hour cycle average water flux of a virgin membrane with air scouring was 2.95L/m2·h-1. Air scouring can help to remove loose foulants from the membrane active layer, thus helping to recover up to 89.5% of the original flux. Chemical cleaning of the fouled active layer of the FO membrane was not as effective as air scouring. Natural organic matter (NOM) characterization methods (liquid chromatography-organic carbon detection (LC-OCD) and 3-D fluorescence excitation emission matrix (FEEM)) 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. Transparent exopolymer particles (TEP) and other biopolymers might be associated with fouling of the membrane on the support layer. A 1% sodium hypochlorite (NaOCl) cleaning solution was proved to be effective for removing the foulants from the support layer and recovering the original flux.