Effects of returning NF concentrate on the MBR-NF process treating antibiotic production wastewater

Abstract

The optimization of the nanofiltration (NF) concentrate backflow ratio (R cb ) and the influence of the NF concentrate on the performance of membrane bioreactornanofiltration (MBR-NF) process treating antibiotic production wastewater were investigated on a laboratory scale. The R cb was optimized at 60 % based on the removal rates of chemical oxygen demand (COD) and NH 4 + -N by MBR. Data analyses indicated that salinity brought by NF concentrate is the major driver leading to the decrease of sludge activity, especially at a high R cb . EPS analysis showed that electric conductivity (EC), proteins in soluble microbial products (SMP), and SMP brought by NF concentrate are the dominant factors causing the severe membrane fouling in MBR. Furthermore, undegradable substances including fulvic acid-like and humic acid-like compounds accumulated in NF concentrate showed significant influence on fouling of NF. MBR could well degrade small MW compounds in NF concentrate, which confirmed the enhancement of organic removal efficiency by recycling the NF concentrate to MBR. The MBR-NF process showed a relatively stable performance at the R cb of 60 % (volume reduction factor (VRF) = 5), and the NF permeate could satisfy the water quality standard for fermentation process with a water recovery rate of 90.9 %.

Recent advances of membrane-based hybrid membrane bioreactors for wastewater reclamation

“…In several documented studies, it was observed that the presence of the recirculation of NF retentate could cause decreasing removal ratios of organics and ammonia in the MBR. Generally, the predominant organics in the MBR permeate are proteins, polysaccharides, and humic-like substances, which can be almost completely rejected by NF membranes (Li et al, 2016). Accordingly, the organic contents in the MBR + NF permeate was negligibly impacted by the NF brine recirculation ratio, showing steady performance of NF membranes.…”

“…Thus, the MF/UF-MBR + NF process is considered as an alternative approach for wastewater reclamation that can compromise between permeability and selectivity. As indicated in Table 1, the MF/UF-MBR + NF process has been successfully applied to treat municipal wastewater (Jacob et al, 2010;Chon et al, 2011;Chon et al, 2013;Kappel et al, 2014;Chon et al, 2015;Woo et al, 2016;Arola et al, 2017;Hacıfazlıoğlu et al, 2019;Arola et al, 2021;Yacouba et al, 2021) and various types of industrial wastewater (Wintgens et al, 2002;Dialynas and Diamadopoulos, 2009;Andrade et al, 2014;Wang et al, 2015a;Hosseini et al, 2016;Li et al, 2016;Reis et al, 2017;Sert et al, 2017;Lan et al, 2018;Moser et al, 2018;Cinperi et al, 2019;Li et al, 2020a;Reis et al, 2020). In most of the studies, the treated water quality could meet the standards of reclaimed water quality for different uses, such as for urban uses, for industrial uses, for groundwater recharge, and for farmland irrigation (WHO, 2006).…”

Reverse Osmosis Performance in MBR-RO Process with Recirculation of RO Concentrate to MBR for Water Reclamation

“…In the last five years, a few researchers have extended their work to investigate the performance of an MBR-NF system for wastewater treatment with NF concentrate recycling to the MBR process, by considering the fouling potential of the membrane in MBR and of the NF membrane, and the quality of NF permeate. Li et al (2016) apply an MBR coupled with an NF membrane in cross-flow mode to treat wastewater from antibiotic production, where NF concentrate is recycled back to the MBR unit [16]. Their results demonstrate that the MBR-NF process is successful in treating the antibiotic wastewater with NF concentrate recirculation, achieving a high water recovery higher than 92% and an excellent water quality that meets the standard for industrial use.…”

“…On the other hand, ionic salts and SMPs brought by NF concentrate recirculation are two main constituents that result in severe membrane fouling in MBR. In addition, the accumulation of non-biodegradable organic components in NF concentrate exhibits a remarkable impact on NF membrane fouling [16]. Before NF process, pre-treatment, including activated carbon, advanced oxidation process (AOPs) and coagulation, has been proposed to reduce membrane fouling [17].…”

Διερεύνηση Του Μικροβιακού Πληθυσμού Και Της Βιοαποδομησιμότητας Διασταλαγμάτων

“…Σε συμφωνία με τα ευρήματα της παρούσας διδακτορικής διατριβής, το κλάσμα των SMP έχει βρεθεί να είναι μεγαλύτερο από αυτό των EPS σε συστήματα που Κεφάλαιο 4 ο : Αποτελέσματα -Συζήτηση 202 επεξεργάζονται υγρά απόβλητα υψηλής αλατότητας (Luo et al, 2015). Επίσης, όμοια με την παρούσα έρευνα, η συγκέντρωση των SMP, η αλατότητα και η διαμεμβρανική πίεση έχουν αναφερθεί να συσχετίζονται σε σύστημα MBR που επεξεργαζόταν υγρό απόβλητο υψηλής συγκέντρωσης σε αντιβιοτικά (Li et al, 2016). Επιπλέον, έχει αναφερθεί ότι οι μικροοργανισμοί της ενεργού ιλύος δύνανται να παράξουν πολυσακχαρίτες κάτω από συνθήκες υψηλής αλατότητας για να αντιμετωπίσουν την ωσμωτική πίεση που ασκείται από την υψηλή συγκέντρωση ιόντων (Jang et al, 2013…”