Evaluating ionic organic draw solutes in osmotic membrane bioreactors for water reuse

Abstract

The performance of two ionic organic draw solutes, namely sodium acetate (NaOAc) and ethylene-diaminetetra acetic acid disodium salt (EDTA-2Na), during osmotic membrane bioreactor (OMBR) operation was investigated in this study. Their performance was compared to that of sodium chloride (NaCl). A reverse osmosis (RO) process was integrated with OMBR to form an OMBR-RO hybrid system for draw solute recovery and clean water production. Results show that the NaOAc and EDTA-2Na draw solutes significantly reduced salinity build-up in the bioreactor in comparison with NaCl during OMBR operation. At the same osmotic pressure, these two ionic organic draw solutions produced slightly lower water flux, but considerably less reverse salt flux than NaCl. Compared to NaCl and NaOAc, EDTA-2Na resulted in significantly less fouling to the forward osmosis membrane. Regardless of the draw solutes, the OMBR-RO hybrid system could remove all 31 trace organic contaminants investigated in this study by more than 97%. Results reported here suggest that ionic organic draw solutes can be used to mitigate salinity build-up in the bioreactor during OMBR operation. AbstractThe performance of two ionic organic draw solutes, namely sodium acetate (NaOAc) and ethylene-diamine-tetra acetic acid disodium salt (EDTA-2Na), during osmotic membrane bioreactor (OMBR) operation was investigated in this study. Their performance was compared to that of sodium chloride (NaCl). A reverse osmosis (RO) process was integrated with OMBR to form an OMBR-RO hybrid system for draw solute recovery and clean water production. Results show that the NaOAc and EDTA-2Na draw solutes significantly reduced salinity build-up in the bioreactor in comparison with NaCl during OMBR operation. At the same osmotic pressure, these two ionic organic draw solutions produced slightly lower water flux, but considerably less reverse salt flux than NaCl. Compared to NaCl and NaOAc, EDTA-2Na resulted in significantly less fouling to the forward osmosis membrane.Regardless of the draw solutes, the OMBR-RO hybrid system could remove all 31 trace organic contaminants investigated in this study by more than 97%. Results reported here suggest that ionic organic draw solutes can be used to mitigate salinity build-up in the bioreactor during OMBR operation.

Performance of a novel baffled osmotic membrane bioreactor-microfiltration hybrid system under continuous operation for simultaneous nutrient removal and mitigation of brine discharge

“…This decrease in SOUR could be well correlated to the increase in salinity during the first week of operation. These observations are consistent with previous studies especially within the first two weeks of operation and could be attributed to the inhibition of elevated bioreactor salinity on biomass growth and activity (Luo et al, 2016a;Reid et al, 2006). Indeed, as can be seen in Fig.…”

A study of the osmotic membrane bioreactor process using a sodium chloride solution and an industrial effluent as draw solutions

“…Recently, several authors have investigated these critical issues in OMBR technology to improve its application. Luo et al [19] studied the salt reverse flux for water reuse in a OMBR using different draw solutions. They concluded that ionic organic draw solutes can mitigate salinity build-up in the mixed liquor.…”

Removal of Organic Micro-Pollutants by Conventional Membrane Bioreactors and High-Retention Membrane Bioreactors

“…The presence of refractory OMPs and their biodegradation by-products adversely affects biodegradation potential of bacteria present in activated sludge [34]. In addition, OMPs concentrations are uncertain in sewage and conventional wastewater treatment facilities are unable to efficiently remove OMPs to the extent for reuse applications [2]. For example, commonly detected OMPs such as ibuprofen showed biodegradable removal of 75% whereas Estrone (E1) and 17-α-Ethinyl estradiol (EE2) achieved 83% and 44% removal [41].…”

“…Rapid population growth, combined with increased agricultural and industrial undertakings is resulting in increased water demand and sewage production [1]. Thus, these persistent drivers of water stress are prompting interest in advanced wastewater treatment techniques that utilize alternative water sources, such as domestic wastewater for water reclamation [2,3]. However, with growing interest in reclaimed water use, safety warrants for health risks-especially when the diverse nature of organic micropollutants found in reclaimed water-must be taken into account [4].…”