Assessing the integration of forward osmosis and anaerobic digestion for simultaneous wastewater treatment and resource recovery

Abstract

This study assessed the performance and key challenges associated with the integration of forward osmosis (FO) and anaerobic digestion for wastewater treatment and resource recovery. Using a thin film composite polyamide FO membrane, maximising the pre-concentration factor (i.e. system water recovery) resulted in the enrichment of organics and salinity in wastewater. Biomethane potential evaluation indicated that methane production increased correspondingly with the FO pre-concentration factor due to the organic retention in the feed solution. At 90% water recovery, about 10% more methane was produced when using NaOAc compared with NaCl because of the contribution of biodegradable reverse NaOAc flux. No negative impact on anaerobic digestion was observed when wastewater was pre-concentrated ten-fold (90% water recovery) for both draw solutes. Interestingly, the unit cost of methane production using NaOAc was slightly lower than NaCl due to the lower reverse solute flux of NaOAc, although NaCl is a much cheaper chemical.

Integration of Forward Osmosis in Municipal Wastewater Treatment Applications

“…20 g L À1 . Ansari et al [91] studied the effects of NaCl on anaerobic treatment of concentrated wastewater effluents in batch mode experiments and observed that by increasing water recovery rates of FO (from 50 to 90%), the anaerobic process achieves higher methane production (approximately 5 times higher), while the presence of salinity has a negligible negative effect.…”

Forward Osmosis as Concentration Process: Review of Opportunities and Challenges

“…The pre-concentration of low strength WW by FO when combined with anaerobic digestion, has several benefits, including higher biogas production, recovery of nutrients, lower FO membrane fouling propensity and smaller digester volume [ 111 ]. A large numbers of studies has been recently published relating the interests, limitations and optimisations of such schemes [ 124 , 125 ]. Several studies have already tried to implement FO for pre concentrating WW for subsequent treatment via anaerobic digestion.…”

Techno-economic analysis of combining forward osmosis-reverse osmosis and anaerobic membrane bioreactor technologies for municipal wastewater treatment and water production

“…However, in this study, the three different recovery scenarios (i.e. 50, 80 and 90%) were selected since (i) high FO recoveries (≥50%) can enhance the operability and applicability of AnMBR technology and (ii) FO recoveries up to 90% have been achieved for municipal wastewater pre-concentration (Ansari et al, 2018).…”