Factors governing the pre-concentration of wastewater using forward osmosis for subsequent resource recovery

Ashley J Ansari; Faisal I Hai; Wenshan Guo; Hao H Ngo; William E Price; Long D Nghiem

doi:10.1016/j.scitotenv.2016.05.139

Factors governing the pre-concentration of wastewater using forward osmosis for subsequent resource recovery

Sci Total Environ. 2016 Oct 1:566-567:559-566. doi: 10.1016/j.scitotenv.2016.05.139. Epub 2016 May 26.

Authors

Ashley J Ansari¹, Faisal I Hai¹, Wenshan Guo², Hao H Ngo², William E Price³, Long D Nghiem⁴

Affiliations

¹ Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia.
² Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
³ Strategic Water Infrastructure Laboratory, School of Chemistry, University of Wollongong, Wollongong, NSW, 2522, Australia.
⁴ Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia. Electronic address: longn@uow.edu.au.

PMID: 27236621
DOI: 10.1016/j.scitotenv.2016.05.139

Abstract

This study demonstrated a technique using forward osmosis (FO) to pre-concentrate the organic matter in raw wastewater, thereby transforming low strength wastewater into an anaerobically digestible solution. The chemical oxygen demand (COD) of raw wastewater was concentrated up to approximately eightfold at a water recovery of 90%. Thus, even low strength wastewater could be pre-concentrated by FO to the range suitable for biogas production via anaerobic treatment. Excessive salinity accumulation in pre-concentrated wastewater was successfully mitigated by adopting ionic organic draw solutes, namely, sodium acetate, and EDTA-2Na. These two draw solutes are also expected to benefit the digestibility of the pre-concentrated wastewater compared to the commonly used draw solute sodium chloride. Significant membrane fouling was observed when operating at 90% water recovery using raw wastewater. Nevertheless, membrane fouling was reversible and was effectively controlled by optimising the hydrodynamic conditions of the cross-flow FO system.

Keywords: Anaerobic digestion; Forward osmosis (FO); Ionic organic draw solution; Membrane fouling; Pre-concentration; Wastewater.

MeSH terms

Biological Oxygen Demand Analysis
Membranes, Artificial*
Osmosis*
Salinity
Waste Disposal, Fluid / methods*
Wastewater / chemistry*

Substances

Membranes, Artificial
Waste Water