Membrane Bioreactor System Research Articles

Effect of quorum quenching on biofouling control and microbial community in membrane bioreactors by Brucella sp. ZJ1

Quorum quenching (QQ) has been demonstrated to be a novel technique for controlling biofouling in membrane bioreactors (MBRs), as it can significantly inhibit biofilm formation by disrupting quorum sensing (QS). The exploration of new QQ bacterial strains and the evaluation of their performance in mitigating membrane fouling in MBR systems is significant. In this study, an efficient QQ strain, Brucella sp. ZJ1 was encapsulated in alginate beads and evaluated for its ability to mitigate biofouling. The findings revealed that MBR with QQ beads extended the operation time by 2–3 times without affecting pollutant degradation. QQ beads maintained approximately 50% QQ activity after more than 50 days operation, indicating a long-lasting and endurable QQ effect. The QQ effect reduced extracellular polymeric substance (EPS) production especially in terms of polysaccharide and protein by more than 40%. QQ beads in the MBR also reduced the cake resistance and the irreversible resistance of membrane biofouling. Metagenomic sequencing suggests that QQ beads suppressed the QS effect and increased the abundance of QQ enzyme genes, ultimately inducing efficient membrane biofouling control.

Kinetic Effects of Ciprofloxacin, Carbamazepine, and Bisphenol on Biomass in Membrane Bioreactor System at Low Temperatures to Treat Urban Wastewater

This study analysed the kinetic results in the presence and absence of micropollutants (bisphenol A, carbamazepine, ciprofloxacin, and the mixture of the three compounds) obtained with respirometric tests with mixed liquor and heterotrophic biomass in a membrane bioreactor (MBR) working for two different hydraulic retention times (12-18 h) and under low-temperature conditions (5-8 °C). Independently of the temperature, the organic substrate was biodegraded faster over a longer hydraulic retention time (HRT) with similar doping, which was probably due to the longer contact time between the substrate and microorganisms within the bioreactor. However, low values of temperature negatively affected the net heterotrophic biomass growth rate, with reductions from 35.03 to 43.66% in phase 1 (12 h HRT) and from 37.18 to 42.77% in phase 2 (18 h HRT). The combined effect of the pharmaceuticals did not worsen the biomass yield compared with the effects caused individually.

Membrane fouling mechanism of submerged membrane bioreactor during erythromycin removal

Background: Based on the previous studies, antibiotics can have affected biological properties of biomass and fouling properties of mixed liquor in aeration tank. The present study was conducted to explore the fouling mechanisms of membrane bioreactor (MBR) system during the treatment of wastewater containing erythromycin (ERY) antibiotic under several mixed liquor suspended solids (MLSS) concentrations. Methods: A lab-scale two-chamber MBR system equipped with a polypropylene hollow fiber submerged membrane was fed with synthetic wastewater containing different initial concentrations of ERY. MBR system was operated under the constant flux mode and different MLSS concentrations (5.0-13.0 g/L) and the obtained results were evaluated using different individual and combined fouling models. Results: The variation of MLSS concentrations had not significantly affected the kind of best-fitted model. From the individual models, the standard model indicated the best performance for permeate prediction under different MLSS concentrations (R2 adj>0.997). For all studied MLSS concentrations, the R2 adj values of combined fouling models were higher than 0.986 and demonstrated good fitness performance of combined models compared to individual models. Overall, the cake-intermediate model showed the lowest fitness, and cake-complete and complete-standard models were the most successful models in filtrated volume prediction in comparison with other combined fouling models. Conclusion: This study indicated that mechanistic models are suitable for fouling prediction of MBR systems in ERY removal and under a wide range of MLSS concentrations and provide valuable information on fouling mechanisms of full-scale MBR systems.

Study the Potential of Biological Growth on Dead-end Hollow Fiber Membrane using Oilfield Effluent

Abstract: Oil and gas-producing countries are suffering from water resource depletion without any treatment or with technologies that have the same impact, regardless of how expensive or large a land area required. On the other hand, domestic wastewater also has many treatment technologies, and biological full cell is one of them. Using an end-of-tube hollow fiber membrane in domestic wastewater allows biological microorganisms to grout and treat the water, whereas using oil-filled water has not been studied so far. This study addresses the potential of biological growth on two different types of dead-end hollow fiber membranes by using three samples of oilfield water i.e., Membrane Aerated Biofilm Reactor OxyMem and MEMCOR® Ultrafiltration. The Membrane Bioreactor Systems are selected for the current studies and scanning electron microscopy (SEM) is used to show the biological growth on selected types of membrane to treat the oilfield wastewater. As a result, the growth in OxyMem is better which is 54% of COD removal and 55% NT removal for 55 days, whereas MEMCOR shows comparatively less growth in SEM results with 33% of COD removal and 9% NT removal during the same period. Therefore, this confirms that both types of membranes can be used to treat oilfield water in biological cells and noticed a better performance in OxyMem compared to MEMCOR.

Study the Potential of Biological Growth on Dead-end Hollow Fiber Membrane using Oilfield Effluent

Abstract: Oil and gas-producing countries are suffering from water resource depletion without any treatment or with technologies that have the same impact, regardless of how expensive or large a land area required. On the other hand, domestic wastewater also has many treatment technologies, and biological full cell is one of them. Using an end-of-tube hollow fiber membrane in domestic wastewater allows biological microorganisms to grout and treat the water, whereas using oil-filled water has not been studied so far. This study addresses the potential of biological growth on two different types of dead-end hollow fiber membranes by using three samples of oilfield water i.e., Membrane Aerated Biofilm Reactor OxyMem and MEMCOR® Ultrafiltration. The Membrane Bioreactor Systems are selected for the current studies and scanning electron microscopy (SEM) is used to show the biological growth on selected types of membrane to treat the oilfield wastewater. As a result, the growth in OxyMem is better which is 54% of COD removal and 55% NT removal for 55 days, whereas MEMCOR shows comparatively less growth in SEM results with 33% of COD removal and 9% NT removal during the same period. Therefore, this confirms that both types of membranes can be used to treat oilfield water in biological cells and noticed a better performance in OxyMem compared to MEMCOR.

Performance and mechanism of microbial fuel cell coupled with anaerobic membrane bioreactor system for fouling control

To remove membrane fouling, a bio-electrochemical system that can generate a micro-electric field and micro-current was constructed. After 11 days of operation, the trans-membrane pressure difference of membrane modules in the open- and closed-circuit groups increased by 35.8 kPa and 6.2 kPa, respectively. The concentrations of total polysaccharide and protein in the open-circuit group were 1.8 and 1.1 times higher than those in the closed-circuit group, respectively. In addition, X-ray photoelectron spectroscopy and thermogravimetric analysis showed that inorganic crystals such as calcium carbonate were present on the membrane surface, and the concentration of calcium ion in the control group was 14.7 times that of the experimental group. High-throughput sequencing demonstrated that the enrichment of some electroactive bacteria and other microorganisms has a positive effect on the control of membrane fouling. Therefore, this system can effectively alleviate membrane fouling of a bioreactor, by targeting the membrane foulants.

Application of Encapsulated Quorum Quenching Strain Acinetobacter pittii HITSZ001 to a Membrane Bioreactor for Biofouling Control

Quorum quenching (QQ) is a novel anti-biofouling strategy for membrane bioreactors (MBRs) used in wastewater treatment. However, actual operation of QQ-MBR systems for wastewater treatment needs to be systematically studied to evaluate the comprehensive effects of QQ on wastewater treatment engineering applications. In this study, a novel QQ strain, Acinetobacter pittii HITSZ001, was encapsulated and applied to a MBR system to evaluate the effects of this organism on real wastewater treatment. To verify the effectiveness of immobilized QQ beads in the MBR system, we examined the MBR effluent quality and sludge characteristics. We also measured the extracellular polymeric substances (EPS) and soluble microbial products (SMP) in the system to determine the effects of the organism on membrane biofouling inhibition. Additionally, changes in microbial communities in the system were analyzed by high-throughput sequencing. The results indicated that Acinetobacter pittii HITSZ001 is a promising strain for biofouling reduction in MBRs treating real wastewater, and that immobilization does not affect the biofouling control potential of QQ bacteria.

The Advancement in Membrane Bioreactor (MBR) Technology toward Sustainable Industrial Wastewater Management.

The advancement in water treatment technology has revolutionized the progress of membrane bioreactor (MBR) technology in the modern era. The large space requirement, low efficiency, and high cost of the traditional activated sludge process have given the necessary space for the MBR system to come into action. The conventional activated sludge (CAS) process and tertiary filtration can be replaced by immersed and side-stream MBR. This article outlines the historical advancement of the MBR process in the treatment of industrial and municipal wastewaters. The structural features and design parameters of MBR, e.g., membrane surface properties, permeate flux, retention time, pH, alkalinity, temperature, cleaning frequency, etc., highly influence the efficiency of the MBR process. The submerged MBR can handle lower permeate flux (requires less power), whereas the side-stream MBR can handle higher permeate flux (requires more power). However, MBR has some operational issues with conventional water treatment technologies. The quality of sludge, equipment requirements, and fouling are major drawbacks of the MBR process. This review paper also deals with the approach to address these constraints. However, given the energy limitations, climatic changes, and resource depletion, conventional wastewater treatment systems face significant obstacles. When compared with CAS, MBR has better permeate quality, simpler operational management, and a reduced footprint requirement. Thus, for sustainable water treatment, MBR can be an efficient tool.

Progress on the Development of Techniques to Remove Contaminants from Wastewater: A Review

The continuous depletion of fresh drinking water resources throughout the world has increased the necessity for the development of new techniques for wastewater treatment and recycling process. Domestic, industrial and agricultural wastes are major sources of aquatic contamination all over the world. Before discharging wastewater into natural water bodies, it must be treated. Apart from primary, secondary and tertiary treatment, membrane separation techniques and electrochemical membrane bioreactors for wastewater treatment have all been studied in this review paper. The electrochemical membrane bioreactor (EMBR) system has a lot of potential for treatment of wastewater and energy recovery. These novel EMBR techniques give feasible solutions for renewable treatment of wastewater and resource resumption.

Machine learning reveals the complex ecological interplay of microbiome in a full-scale membrane bioreactor wastewater treatment plant

Membrane bioreactor (MBR) systems are one of the most widely used wastewater treatment processes for various municipal and industrial waste streams. The present study aimed to advance the understanding of ecologically important keystone taxa that play an important role in full-scale MBR systems. A machine-learning (ML) modeling framework based on microbiome data was developed to successfully predict, with an average accuracy of >91.6%, the operational characteristics of three representative full-scale wastewater systems: an MBR, a conventional activated sludge system, and a sequencing batch reactor. ML-based feature-importance analysis identified Ferruginibacter as a keystone organism in the MBR system. The phylogeny and known ecophysiology of members of Ferruginibacter supported their role in metabolizing complex organic polymers (e.g., extracellular polymeric substances) in MBR systems characterized by high concentrations of mixed liquor suspended solids and a high solid retention time. ML regression modeling also revealed temporal patterns of Ferruginibacter in response to water temperature. ML modeling was thus successfully employed in the present study to investigate complex/non-linear relationships between keystone taxa and environmental conditions that cannot be detected using conventional approaches. Overall, our microbiome-data-enabled ML modeling approach represents a methodological advance for identifying keystone taxa and their complex ecological interactions, which has implications for the sustainable and predictive management of MBR systems.

Fate and removal of iodinated X-ray contrast media in membrane bioreactor: Microbial dynamics and effects of different operational parameters

Iodinated X-ray contrast media (ICM) are mainly used in medical sector, and their presence in environmental waters is a cause of concern as they are capable of forming highly toxic iodinated disinfection byproducts. In the present study, the removal mechanisms of the three ICM- iohexol, iopromide, and iopamidol were elucidated in a lab-scale aerobic membrane bioreactor (MBR). At steady-state operation (solids retention time (SRT)- 70 days, organic loading rate (OLR)- 0.80 KgCOD/m3-day, nitrogen loading rate (NLR)- 0.08 KgNH4-N/m3-day, hydraulic retention time (HRT)- 12 h), the average removal of iohexol and iopromide was found to be 34.9 and 45.2 %, respectively, whereas iopamidol proved to be highly recalcitrant in aerobic conditions of the MBR (removal <10 % in all phases of the MBR operation). Further, through batch kinetic studies and mass balance analysis, it was observed that ICM were primarily biotransformed in the MBR system and biosorption (Kd < 10 L/Kg) was negligible. The biodegradation rate coefficient values (Kbiol) of the ICM were found to be <0.65 L/g-d which indicate that biotransformation rate of ICM was slow. Increased OLR (1.60 KgCOD/m3-day) and reduced SRT (20 days) were found to negatively affect the removal of the ICM. Further, the removal of ICM was found to depend on its initial concentration, and the increment in the ammonium loading (0.16 KgNH4-N/m3-day) did not favor its removal. The dosing of ICM altered the microbial dynamics of the mixed liquor and reduced the microbial diversity and richness. Bdellovibrio, Zoogloea, and bacteria belonging to TM7-3 class, Cryomorphaceae and Hyphomonadaceae families may contribute in ICM biotransformation.

Effect of mixing iron-containing sludge to domestic wastewater on wastewater characteristics under different conditions: types of domestic wastewater, varying pH and mixing ratios

Large volumes of iron-containing sludge (Fe-Sludge) would be generated with the application of iron salts in drinking water treatment plants, which must be disposed appropriately. One of the common disposal solutions for Fe-Sludge is through direct disposal into the municipal sewer system, whereby it would be mixed with domestic wastewater and treated in the wastewater treatment plant. To better understand the properties of Fe-Sludge and the effect of dosing Fe-Sludge to the real domestic wastewater (WW) on the wastewater characteristics, a serial batch tests were conducted on a local wastewater reclamation plant (WRP). It was found that the impact of dosing Fe-Sludge at a Fe/P ratio of 5 did not vary with the types of WW, i.e., filtered or non-filtered by the 5 mm screen. In addition, the soluble organic, phosphate and total soluble iron concentrations mostly decreased with the dosing of Fe-Sludge within the dosage range of 0–5 (Fe/P ratio). In contrast, the suspended solid (SS) and volatile suspended solid (VSS) concentrations increased with the dosage of Fe-Sludge within the dosage range of 0–5 (Fe/P ratio). Furthermore, the pH condition of the domestic wastewater affected the phosphate removal efficiency by Fe-Sludge and influenced the total soluble iron concentration and iron species distribution. These findings will provide fundamental support for the further study of the effect of Fe-Sludge on the biological treatment performance and membrane filtration performance of the membrane bioreactor (MBR) system.

Evaluating the Optimal Oil Concentrations in the Startup Performance of a Membrane Bioreactor Treating Oily Noodle-soup Wastewater

The discharge of high-strength oily wastewater adversely affects the environment; therefore, the treatment of wastewater containing fats, oils, and grease from the food industry is of importance. In this study, we used a membrane bioreactor (MBR) to treat Ramen noodle-soup wastewater, and we evaluated the optimal oil concentration in the wastewater for the startup of the MBR treatment in winter and summer. The MBR system had a sufficient startup in both seasons when fed with a 20-fold dilution of the original oily wastewater, containing approximately 950 to 1,200 mg/L oil and approximately 3,000 to 4,400 mg/L biological oxygen demand (BOD; BOD-SS load of 0.1 to 0.2 kg/kg/d). The reactor performance in winter were relatively stable during the operation. While, activated sludge microbes in summer were not highly active with a 40-fold dilution of wastewater, because of the decreased mixed liquor suspended solid concentration during the operation period. Population shifts in the sludge microbiome with increasing oil concentrations were analyzed using high-throughput sequencing, and the relative abundance of operational taxonomic units belonging to the phylum Bacteroidetes were highest in both winter and summer when fed with 20-fold dilution of the wastewater. In particular, the family Chitinophagaceae was dominant, with relative abundances of 13.5% in winter and 5.1% in summer, suggesting that this family may play important roles in the startup of a MBR treating the wastewater.

Review on MBR Technologies for Emerging Pollutant Removal from Wastewater and Their Associated Antifouling Strategies

It was necessary to reclaim water from wastewater to tackle water scarcity issues. However, it was difficult to treat waste-water for resue purpose through conventinal treatment technologies due to the wastewater contains various emerging contaminants. Membrane bioreactors (MBRs) were promising techniques to reclaim wastewater, which hybrid activity sludge and membrane technol- ogies. Although it was a challenge to eliminate the emerging contaminants efficiently through conventional MBRs due to specific chem- ical structures of these chemicals, more and more novel hybrid MBRs were applied to the removal of emerging contaminants. The evo- lution of MBR systems for treating emerging pollutants was summarized in this review. In addition, the process of biofouling on mem- branes and the development of relevant antifouling technologies were investigated. Besides, the perspectives of MBR systems on the ap- plication of emerging pollutant treatment were provided, which would help support the research and development of technologies in the field of water reclaiming in the future.

Municipal wastewater treatment and recycle by an electrocoagulation process and a submerged membrane bioreactor system

To remove phosphates and nitrates from municipal wastewater, an electrocoagulation process with membrane bioreactor process (EC-MBR) was used. Experiments were carried out incrementally to evaluate the new design. In a lab-scale (EC-MBR) treatment of municipal wastewater, the structure and distribution of the organic matter removal utilizing the membrane are being examined. The study's objectives were to evaluate the efficiency of the Al-Hawraa wastewater's organic matter removal process for nitrate (NO-3) and phosphate (PO4-3) as well as how it related to machine learning indicators. It was chosen to use an EC-MBR with operational parameters of 25 Co, pH 7 and DO (4-6 mg/L), initial and final concentrations of NO-3 (4.4-0.6 mg/L), and (PO4-3) (6.0-0.1 mg/L) to collect and analyze effluent from municipal wastewater treated using biological and chemical methods. According to the results, it may be possible to measure the effectiveness of organic matter removal using a neural network method. The results also showed that an overall reactor had agreeablemaximum NO-3 and (PO4-3) removal efficiencies of (87.6% and 98.1%), respectively. The accuracy model by its (98.1 and 85.7) for both NO-3 and (PO4-3) was effective, according to the models' accuracy results.

Simultaneous Carbamazepine and Phosphate Removal from a Moving-Bed Membrane Bioreactor Effluent by the Electrochemical Process: Treatment Optimization by Factorial Design.

Pharmaceutical and personal care products are frequently used in various fields and released into water bodies from the outlets of wastewater treatment plants. These products can harm the environment and human health even at low concentrations. Carbamazepine (CBZ), the most persistent pharmaceutical, has frequently been found in surface waters that bypassed the secondary treatments of conventional activated sludge. In addition, the treatment of phosphate in wastewater by the electrochemical process has recently attracted much attention because of its ability to remove, recover, and prevent environmental problems associated with eutrophication. This study proposes using the electrochemical process as an advanced oxidation process to simultaneously treat CBZ and phosphate from the moving-bed membrane bioreactor effluent. The study includes a long-term survey of CBZ treatment efficiency and common parameters of synthetic wastewater in the moving-bed membrane bioreactor system. Afterward, the electrochemical process is applied as an advanced oxidation process for the simultaneous removal of CBZ and phosphate from the moving-bed membrane bioreactor. Under the investigated conditions, CBZ has proven not to be an inhibitor of microbial activity, as evidenced by the high extent of chemical oxygen demand and nutrient removal. Using a factorial design, the electrochemical process using Pt/Ti as anode and cathode under optimal conditions (reaction time-80 min, bias potential-3 V, and electrode distance-1 cm) resulted in as high as 56.94% CBZ and 95.95% phosphate removal, respectively. The results demonstrated the ability to combine an electrochemical and a moving-bed membrane bioreactor process to simultaneously remove CBZ and phosphate in wastewater.

Biochar-assisted anaerobic membrane bioreactor towards high-efficient energy recovery from swine wastewater: Performances and the potential mechanisms

A high-efficient energy recovery system of biochar-assisted anaerobic membrane bioreactor (BC-AnMBR) was established for swine wastewater treatment. Comparing with a conventional AnMBR, biochar addition accelerated volatile fatty acids (VFA) degradation during start-up stage, thereby shortened start-up duration by 44.0 %. Under a high organic loading rate (OLR) of 21.1 gCOD/L/d, BC-AnMBR promoted COD removal efficiency from 90.1 % to 95.2 %, and maintained a high methane production rate of 4.8L CH4/L/d. The relative abundance of Methanosaeta declined from 53.9 % in conventional AnMBR to 21.0 % in BC-AnMBR, whereas that of Methanobrevibacter dramatically increased from 10.3 % to 70.9 %, respectively. Metabolic pathway analysis revealed that biochar not only strengthened hydrogenotrophic methanogenesis pathway, but also upregulated the genes encoding electron transfer carriers and riboflavin metabolism, suggesting the role of biochar facilitating direct interspecies electron transfer for syntrophic methanogenesis. The excellent energy yield performances under high OLR confirmed BC-AnMBR as an advanced system for high-strength swine wastewater treatment.

Modified Graphene Oxide/Polyvinyl Chloride Membranes for Wastewater Treatment

AbstractGraphene oxide (GO) was modified by citric acid (CA) and embedded into polyvinyl chloride (PVC) membranes. The PVC/GO‐CA (0.15 wt %) membrane showed the best hydrophilicity, porosity, and tensile strength. The results of membranes' performance in a membrane bioreactor (MBR) system demonstrated that the critical flux had a noticeable improvement after adding 0.15 wt % GO‐CA. Also, the irreversible fouling ratio of PVC/GO‐CA membranes was lower than that of the neat PVC membrane, indicating an improvement in antifouling properties of the nanocomposite membrane. Moreover, the soluble microbial product (SMP) and the extracellular polymeric substance (EPS) of the cake layer reduced for the PVC/GO‐CA (0.15 wt %) membrane because of its higher hydrophilicity and better antifouling behavior.

Fabrication, characterization and treatment of polymeric membranes with submerged membrane bioreactor system: fruit juice industry wastewater

Fabrication, characterization and treatment of polymeric membranes with submerged membrane bioreactor system: fruit juice industry wastewater

Evaluating Laboratory Side-stream Membrane Bioreactor and Nanofiltration System for Treating Domestic Wastewater and Reuse

This paper presents Membrane Bioreactor (MBR) and Nanofiltration (NF) systems as alternative and effective approaches for treatment and reusing domestic sewage. The goal is to investigate the general performance of a membrane bioreactor and nanofilteration membrane ability to satisfy water reuse requirements using water quality index such as total suspended solids (TSS), chemical oxygen demand (COD), and ammonia (NH3). The findings show that the MBR system produces high-quality permeating water. TSS, COD and NH3 rejection rates were 99%, 90.3%, and 82.5% (on average). In addition, MBR technology is quite successful as a pre-NF treatment. We also evaluated how pressure and temperature affect the effectiveness of the NF membrane removal of TDS, COD, ammonia, and permeating flux. The results showed that the applied pressure has a favorable impact on the total removal rate; however, the feeding temperature has a negative impact. The feeding temperature, in addition to pressure, has a good influence on the flux of the NF system.