Combination Of Membrane Bioreactor Research Articles

Combination of membrane bioreactor with chemical coagulation for the treatment of real pharmaceutical wastewater: Comparison of simultaneous and consecutive pre-treatment of coagulation on MBR performance

In this work, the combination of the coagulation process with the MBR system to reclaim effluent in pharmaceutical industries was investigated. In this research, comparison/concentration optimization of two modes of integrations, including simultaneous; one-step one pot, and consecutive coagulation MBR were investigated. Results showed that COD removal in simultaneous and consecutive modes at optimum values were 85 % and 95.8 %, respectively, which were considerably higher than that of control MBR; 53.89 %. The total fouling ratio for control MBR, simultaneous, and consecutive modes at optimum conditions were 70.69 %, 37.3 %, and 42.5 %, respectively, confirming that the integrated coagulation process and MBR system were considerably effective. Analyzing the secreted metabolite, e.g. protein, carbohydrate, and LB/TB-EPS ratio in the MBR tank as well as on the membrane surface showed that the charge-neutralization and entrapment of bio-foulants by aggregated clots during the coagulation hinder the adhesion of the biofouling agents on the membrane surface, therefore in-line with the flux attenuation trend, lower metabolite concentration results in less membrane fouling. It was found that simultaneous coagulative MBR with 100 mg/L FeCl3 concentration demonstrates better fouling mitigation in comparison with consecutive (even with poly aluminum chloride; PACl as coagulant aid) MBR, while the latter mode shows better performance in terms of wastewater treatment. These findings open avenues for future techno-economic assessments of a coagulation-assisted MBR, providing a cost-effective solution for treating high-strength wastewater on a larger scale.

Filtration Methods for Microplastic Removal in Wastewater Streams — A Review

Microplastics are commonly recognized as environmental and biotic contaminants. The prevalent presence of microplastics in aquatic settings raises concerns about plastic pollution. Therefore, it is critical to develop methods that can eliminate these microplastics with low cost and high effectiveness. This review concisely provides an overview of various methods and technologies for removing microplastics from wastewater and marine environments. Dynamic membranes and membrane bioreactors are effective in removing microplastics from wastewater. Chemical methods such as coagulation and sedimentation, electrocoagulation, and sol-gel reactions can also be used for microplastic removal. Biological methods such as the use of microorganisms and fungi are also effective for microplastic degradation. Advanced filtration technologies like a combination of membrane bioreactor and activated sludge method show high microplastic removal efficiency.

Microplastics in landfill leachate: Occurrence, health concerns, and removal strategies

Landfills are commonly used to manage solid waste, but they can contribute to microplastic (MPs) pollution. As plastic waste degrades in landfills, MPs are released into the surrounding environment, contaminating soil, groundwater, and surface water. This poses a threat to human health and the environment, as MPs can adsorb toxic substances. This paper provides a comprehensive review of the degradation process of macroplastics into microplastics, the types of MPs found in landfill leachate (LL), and the potential toxicity of microplastic pollution. The study also evaluates various physical-chemical and biological treatment methods for removing MPs from wastewater. The concentration of MPs in young landfills is higher than in old landfills, and specific polymers such as polypropylene, polystyrene, nylon, and polycarbonate contribute significantly to microplastic contamination. Primary treatments such as chemical precipitation and electrocoagulation can remove up to 60–99% of total MPs from wastewater, while tertiary treatments such as sand filtration, ultrafiltration, and reverse osmosis can remove up to 90–99%. Advanced techniques, such as a combination of membrane bioreactor, ultrafiltration, and nanofiltration (MBR + UF + NF), can achieve even higher removal rates. Overall, this paper highlights the importance of continuous monitoring of microplastic pollution and the need for effective microplastic removal from LL to protect human and environmental health. However, more research is needed to determine the actual cost and feasibility of these treatment processes at a larger scale.

Reuse-focused selection of appropriate technologies for municipal wastewater treatment: a multi-criteria approach.

Wastewater treatment technologies (WWTTs) are employed across the world, and the selection is mainly based on ‘past experiences’ aimed at ‘pollution prevention’ in the receiving water bodies. This paper aims to develop a methodology for the selection of an appropriate wastewater treatment chain that produces effluent suitable for the defined reuse. Adopting the least weighted cost approach, four decision criteria: Capital cost, Operation and Maintenance cost, Land requirement, and Energy requirement, have been used and the Full Consistency Method (FUCOM) has been employed for obtaining weights. Quality expectations for 14 reuses have been enlisted, and 25 WWTTs have been evaluated in a total of 360 combinations. In Kanpur city, for water reuse in industrial cooling under restricted land and challenging influent quality conditions, a combination of Membrane Bioreactor (MBR) with Wuhrmann process (WP) is obtained as the most preferred suggestion. For non-potable domestic reuse, Anaerobic Anoxic Oxic (A2O) with Ultrafiltration (UF) and Reverse Osmosis (RO) is the most preferred combination. In Varanasi city, for vehicular washing operations and for flow augmentation (inland surface water), under energy-constraint scenario, high-rate activated sludge-based biological filtration and oxygenated reactor (BIOFOR-F) is suggested. For technology supplementation to existing ASP-based STPs in the city to obtain effluent for inland surface water augmentation, WP in combination with microfiltration (MF) and reverse osmosis (RO) is suggested. Thus, the developed model may be used as a decision-making tool for planning a reuse-focused water reclamation program or for upgradation of existing STPs as per resource availability and target reuse objectives.

Advanced Phosphorus Recovery from Municipal Wastewater using Anoxic/Aerobic Membrane Bioreactors and Magnesium Carbonate-Based Pellets.

Effective recovery of phosphorus from municipal wastewater could be one of the best practical alternatives to protect aquatic environments from eutrophication and save natural phosphorus resources. This paper focuses on validating magnesium carbonate (MgCO3)-based pellets combined with a bench-scale anoxic/aerobic membrane bioreactor (MBR) system for advanced phosphorus recovery from municipal wastewater. As the flow rate of wastewater into the MgCO3 column decreased from 10 L/d to 2.5 L/d, the phosphorus recovery rate of the MgCO3-based pellets increased from 54.3 to 93.5%. However, the column's severe clogging was found after a 13-days operation due to the high removal of total suspended solids (TSS) (~82%) through the MgCO3 column. The anoxic/aerobic MBR introduction provided efficient removal of TSS, organic matter, and ammonia nitrogen before the MgCO3 column. The combination of MBR with the MgCO3 column achieved 73.1% phosphorus recovery from municipal wastewater without physical clogging. The P recovery capacity of the MgCO3-based pellets was maintained at 0.47 mg ortho-P/g MgCO3-based pellet during the continuous operation. Physical and chemical properties of MgCO3-based pellets before and after the experiment were characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface area analyzer.

Leachate treatment: Assessment of the systemic changes in the composition and biodegradability of leachates originating in an open co-composting facility in Canada

Leachate characterization is critical in order to design adequate treatment systems as well as establish effective management strategies that take into account systemic factors affecting the composition and biodegradability of the contamination. The purpose of this study is to provide an exhaustive analysis of composting leachate composition, with a particular focus on leachate from Northern climates. Leachate samples were analyzed on a monthly basis (from May to October) for 25 water quality parameters in three different locations (fresh leachate and two retention basins) at a co-composting facility located in Quebec, Canada. The highest concentrations of total nitrogen, ammoniacal nitrogen, total phosphorus, chemical oxygen demand and hazardous metals (Al, Cd, Cr, Ni, Pb, and Zn) were all measured in July and August, which correlates with the thermophilic phase of the composting process. A statistical analysis was performed to correlate both the climatic and operational influence factors to the leachate contamination. Temperature was found to be positively correlated, while precipitations were negatively correlated, with most quality parameters in fresh leachate. The biodegradability of organic contamination was also studied. The lowest biodegradability was observed in July and August as well. During these two months, the organic contamination was comprised of >85% of fulvic- and humic-like substance due to the humification of organic waste during the composting process. BOD5/COD ratios were <0,1 for at all locations. Finally, the suggested treatment option for this wastewater is the combination of membrane bioreactors with advanced oxidation processes.

Fate and distribution of phosphorus in laboratory-scale membrane bioreactors

In this study, the removal efficiencies of phosphorus from synthetic wastewater using laboratory-scale membrane bioreactors (MBRs) with the addition of different iron salts were investigated. The distributions of phosphorus in the effluent, suspension, and sludge of the MBR systems after the addition of iron salts were analyzed. The removal efficiency of phosphorus in actual domestic sewage via the combination of MBR and Fe(II) was also investigated. The results indicated that after the MBR system effluent stabilized, the added Fe(II) was more efficient than Fe(III) was in removing phosphorus. Among the suspensions present in different zones of the MBR systems, the phosphorus concentrations varied significantly. Namely, the concentration of phosphorus in the first anoxic zone was the highest, for which the concentration of phosphorus in the MBR with added Fe(II) was higher than that in the MBR with added Fe(III). In addition, the percentage of the dissociable phosphorus in the sludge was relatively low. For the treatment of actual domestic sewage using the combination of MBR and Fe(II), a specific concentration of Fe(II) resulted in greater than 99% phosphorus removal efficiency as well as a stable effluent concentration. Furthermore, microbes present in the sludge exhibited better tolerance to Fe(II).

Removal of Pollutants in Different Landfill Leachate Treatment Processes on the Basis of Organic Matter Fractionation.

A combination of processes was required for the proper treatment of old landfill leachate, as it contained a high concentration of pollutants. Humic substances comprised half of the total organic carbon in the raw leachate. Mobility of di(2-ethylhexyl) phthalate (DEHP) and metals could depend on the fate of these substances. Characterization of carbon in raw leachate and effluent of the membrane bioreactor, biofiltration, electro-oxidation, electro-coagulation, and nanofiltration showed complete removal of suspended solids and colloids. Physical processes could not remove the hydrophilic fraction due to its lower molecular weight. However, high removal of the hydrophilic fraction with a molecular weight <500 Da was expected in the biological process. In comparison with fulvic acid, larger sized humic acid resulted in complete removal by physicochemical processes. Because of DEHP partitioning on dissolved organic matter, especially on humic substances, its removal could be correlated with total organic carbon removal. Metals such as iron, aluminum, magnesium, and lead showed removal efficiency >80% in biological processes. Electro-deposition on the surface of an electrode and precipitation by hydroxide resulted in removal efficiencies >90 and >50% in electro-coagulation and electro-oxidation, respectively. Rejection of metals by nanofiltration was >80% and depended on the size and charge of cation. All in all, a combination of membrane bioreactor and nanofiltration seems to be the optimal process configuration for efficient treatment of old landfill leachate.

Membrane fouling control and enhanced removal of pharmaceuticals and personal care products by coagulation-MBR

We investigated the effects of the addition of two coagulants−polyaluminium chloride (PACl) and chitosan−into the membrane bioreactor (MBR) process on membrane fouling and the removal of pharmaceuticals and personal care products (PPCPs). Their addition at optimized dosages improved the permeability of the membrane by reducing the concentration of soluble microbial products in mixed liquor, the content of inorganic elements, and irreversible fouling of the membrane surface. During long-term operation, the addition of PACl increased removal efficiencies of tetracycline, mefenamic acid, atenolol, furosemide, ketoprofen, and diclofenac by 17–23%. The comparative evaluation using mass balance calculations between coagulation-MBR (with PACl addition) and control-MBR (without PACl addition) showed that enhanced biodegradability played a key role in improving removal efficiencies of some PPCPs in coagulation-MBR. Coagulation-MBR also had higher oxygen uptake rates and specific nitrification rates of microorganisms. Overall, our findings suggest that the combination of MBR with coagulation reduced membrane fouling, lengthening operation period of the membrane, and improved the removal of some PPCPs as a result of enhanced biodegradability.

Synthetic hospital wastewater treatment by coupling submerged membrane bioreactor and electrochemical advanced oxidation process: Kinetic study and toxicity assessment

In this work, the combination of membrane bioreactor (MBR) and electro-oxidation (EO) process was studied for the treatment of a synthetic hospital wastewater fortified with four pharmaceutical pollutants namely carbamazepine (CBZ), ibuprofen (IBU), estradiol (E-E) at a concentration of 10 μg L−1 venlafaxine (VEN) at 0.2 μg L−1. Two treatment configurations were studied: EO process as pre-treatment and post-treatment. Wastewater treatment with MBR alone shows high removal percentages of IBU and E-E (∼90%). Unlikely for CBZ and VEN, a low elimination percentage (∼10%) was observed. The hydraulic and the solid retention times (HRT and SRT) were 18 h and 140 d respectively, while the biomass concentration in the MBR was 16.5 g L−1. To enhance pharmaceuticals elimination, an EO pretreatment was conducted during 40 min at 2 A. This configuration allowed a 92% removal for VEN, which was far greater than both treatments alone, with lower than 30% and 50% for MBR and EO, respectively. The MBR-EO coupling (EO as post-treatment) allows high removal percentages (∼97%) of the four pharmaceutical pollutants after 40 min of treatment at a current intensity of 0.5 A with Nb/BDD as electrodes. This configuration appears to be very effective compared to the first configuration (EO-MBR) where EO process is used as a pre-treatment. Toxicity assessment showed that the treated effluent of this configuration is not toxic to Daphnia magna except at 100% v/v. The MBR-EO coupling appears to be a promising treatment for contaminated hospital effluents.

COUPLING OF MEMBRANE BIOREACTOR AND OZONATION FOR REMOVAL OF ANTIBIOTICS FROM HOSPITAL WASTEWATER

Antibiotic residues in the environment and their potential toxic effects have been considered as one of the emerging research area in the environmental field. Their continuous introduction in our environment may increase their negative impacts on human health. In this study, the eliminations of antibiotic such as Norfloxacin (NOR), Ciprofloxacin (CIP), Ofloxacin (OFL) and Sulfamethoxazole (SMZ) in wastewater of hospital were processed by membrane bioreactor (MBR) coupled with ozonation process. In particular, the MBR was applied for the antibiotic removals followed by ozonation process as a post-treatment stage to create an adequate integration to enhance removal efficiency. Achieved results after MBR treatment showed that the removal efficiency of NOR, CIP, OFL and SMZ were 90 ± 4.0% , 83 ± 13% , 81 ± 13 % and 39 ± 6%, respectivley. In addition, those antibiotic matters were continously removed by ozonation process with the removal efficiency of 87±9.0% , 83±1.0% , 81±2.3% and 66±2.3% for NOR, CIP, OFL and SMZ, respectively. In summary, antibiotics could be basically limited by the combination of MBR and ozonation before discharging in aquatic environment.

The color removal and fate of organic pollutants in a pilot-scale MBR-NF combined process treating textile wastewater with high water recovery.

A combination of membrane bioreactor (MBR) and nanofiltration (NF) was tested at pilot-scale treating textile wastewater from the wastewater treatment station of a textile mill in Wuqing District of Tianjin (China). The MBR-NF process showed a much better treatment efficiency on the removal of the chemical oxygen demand, total organic carbon, color and turbidity in comparison with the conventional processes. The water recovery rate was enhanced to over 90% through the recycling of NF concentrate to the MBR, while the MBR-NF showed a stable permeate water quality that met with standards and could be directly discharged or further reused. The recycled NF concentrate caused an accumulation of refractory compounds in the MBR, which significantly influenced the treatment efficiency of the MBR. However, the sludge characteristics showed that the activated sludge activity was not obviously inhibited. The results of fluorescence spectra and molecular weight distribution indicated that those recalcitrant pollutants were mostly protein-like substances and a small amount of humic acid-like substances (650-6,000 Da), which contributed to membrane fouling of NF. Although the penetrated protein-like substances caused the residual color in NF permeate, the MBR-NF process was suitable for the advanced treatment and reclamation of textile wastewater under high water yield.

Full-scale experience with the membrane bioreactor-reverse osmosis water reclamation process

The Gippsland Water Factory (GWF), owned and operated by Gippsland Water in south eastern Australia, is a 35,000 m3/day water reclamation facility which treats 16,000 m3/day of domestic wastewater and 19,000 m3/day of industrial (pulp and paper) wastewater through parallel membrane-bioreactor (MBR)-based treatment trains prior to discharge to the Pacific Ocean via the Regional Outfall Sewer. A portion of the domestic train MBR effluent is further treated through a chloramination and reverse osmosis (RO) system for reclamation, as needed to augment the regional water supply, and is supplied to Australia Paper, the source of the industrial wastewater treated at the GWF. While use of the MBR/RO combination for water reclamation is expected to provide advantages, little full-scale experience exists. Consequently, this paper reports operational and performance results for the first four years of operation for the MBR/RO water reclamation train. Details are provided, not only on process performance, but also on the resolution of equipment and plant performance issues along with ongoing plant optimization. On the basis of these operating results, it is concluded that the combination of MBR and RO is a reliable and robust option for producing high-quality reclaimed water from municipal wastewater.

Advanced treatment of semiconductor wastewater by combined MBR–RO technology

The combination of membrane bioreactor and reverse osmosis (MBR–RO) is becoming an attractive technology for wastewater reclamation and reuse. In this work, the combined MBR–RO technology was applied to treat the semiconductor wastewater through a two-phase (I, II) operation. To demonstrate the feasibility of this technology, the operational performances of MBR and RO were investigated in Phase I. The good operational stability, high contaminant removal efficiency of the combined system, as well as qualified treated water for reuse were observed. To understand the possible fouling characteristics of RO membrane in a long-term operation, the antiscalant addition and chemical cleaning in RO process were abolished in Phase II. The membrane autopsy analysis showed that the dominant foulants on the RO membrane surface were loose inorganic deposits with plate-like morphology, while the biological and organic fouling were ignorable. The major component of the foulants was BaSO4, with small amounts of SrSO4 and deposits involving Ca, Si, Al, Mg, Fe and Zn. The foulants could be effectively removed by chemical cleaning of HCl–NaOH/EDTA. After the cleaning, the RO membrane permeability was recovered to the fresh one. This work provides a deep understanding of treating the semiconductor wastewater by MBR–RO technology for industrial application.

Removal of emerging trace organic contaminants by MBR-based hybrid treatment processes

The aim of this study was to demonstrate the complementarity of combining membrane bioreactor (MBR) treatment with UV oxidation or high pressure membrane filtration processes such as nanofiltration (NF) or reverse osmosis (RO) for the removal of trace organic contaminants (TrOC). The results suggest that the removal mechanisms of TrOC by either UV oxidation or NF/RO membrane filtration differ significantly from those of an MBR system. Thus, they can complement MBR treatment very well to significantly improve the removal of TrOC. MBR treatment can effectively remove hydrophobic and readily biodegradable hydrophilic TrOC. The remaining hydrophilic and biologically persistent TrOC were shown to be effectively removed by either UV oxidation or NF/RO membrane filtration. The combination of MBR with UV oxidation or NF/RO membrane filtration resulted in a removal ranging from 85% to complete removal (or removal to below the analytical detection limit) of all 22 TrOC selected in this study. In particular, it is noteworthy that although MBR treatment and direct UV oxidation separately achieved low removal of carbamazepine (a widely reported problematic compound), the combination of these two processes resulted in more than 96% removal.

Effects of the pre‐treatment alternatives on the treatment of oil‐gas field produced water by nanofiltration and reverse osmosis membranes

AbstractBackgroundProduced water is generated in huge volumes from oil and gas production facilities. Different alternatives including physical, chemical, and biological methods can be applied for the treatment of produced waters. In this study, different pre‐treatment alternatives used before a final nanofiltration and reverse osmosis membrane system were evaluated. A membrane bioreactor and pressurized microfiltration and ultrafiltration systems were used in the pre‐treatment stage.ResultsAccording to the results, the highest flux was obtained by the combination of ultrafiltration/microfiltration and nanofiltration; whereas, the maximum removal efficiencies for conductivity and chemical oxygen demand were obtained by the combination of membrane bioreactor and reverse osmosis systems.ConclusionThe results of this study show that the emphasis should be placed on applying the right combination of membrane treatment processes instead of focusing only on pre‐ or final treatment units. © 2012 Society of Chemical Industry

Combining MBR and NF/RO membrane filtration for the removal of trace organics in indirect potable water reuse applications

The aim of this study was to demonstrate the complementarities of combining membrane bioreactor (MBR) treatment with nanofiltration (NF) or reverse osmosis (RO) membrane filtration for the removal of trace organic contaminants for potential indirect potable water recycling applications. Four commercially available NF/RO membranes, namely NF270, NF90, BW30 and ESPA2, were selected for this investigation. Challenge tests were conducted with 40 trace organic compounds at concentrations of approximately 2 μg/L in initial wastewater solutions using a laboratory scale MBR system and a cross-flow NF/RO rig. The results suggest that the MBR system effectively removes hydrophobic and biodegradable trace organic compounds. The adsorption of these hydrophobic compounds onto the MBR mixed liquor suspended solids (MLSS) leads to an extended retention time in the biological reactor, thereby enhancing their removal. The remaining, mostly hydrophilic, trace organic compounds were shown to be effectively removed by NF/RO membranes. The combination of MBR and a low pressure RO membrane resulted in more than 95% removal or removal to below the analytical detection limit of all 40 trace organic compounds investigated in this study. The results also suggest that NF/RO membrane fouling could be mitigated by appropriate membrane selection. Despite a relatively high initial permeate flux, negligible flow rate decline was observed with an NF membrane and a low pressure RO membrane over more than 25 h of filtration, possibly due to the smooth surfaces of these two particular membranes.

Developing industrial water reuse synergies in Port Melbourne: cost effectiveness, barriers and opportunities

Urban water scarcity from ongoing drought and an increasing population are driving a range of water saving options to be explored in Melbourne (Australia). This paper assesses the cost effectiveness of five water treatment and industrial reuse options in the Fishermans Bend industrial area at Port Melbourne. In consultation with industrial stakeholders and the local water utility, the study design began by identifying potential water sources and sinks in the area. Treatment technologies for each option – using a combination of membrane bioreactors (MBR) and in some cases reverse osmosis (RO) technologies – were developed. In evaluating the potential for future implementation, the cost effectiveness ($/kiloLitre) was assessed relative to water supply augmentation and water demand management options available in Melbourne. Additionally, the opportunities and barriers for option implementation in Port Melbourne were contrasted with the Kwinana Industrial Area, Western Australia where many regional synergy projects have been undertaken. This research identifies that the future implementation of industrial ecology opportunities requires strong and ongoing stakeholder involvement as described in this paper.

Integration of a membrane bioreactor coupled with reverse osmosis for advanced treatment of municipal wastewater

This work investigated the evaluation of a pilot-scale membrane bioreactor (MBR) system in combination with a reverse osmosis (RO) unit. The MBR treatment with biomass concentration (MLSS) of 5 mg/L provided a high level of treatment for primary municipal wastewater. The removal of SS reached 99.99% resulting in a MBR effluent with SS levels below 1 mg/L. This demonstrated excellent solids separation achieved by the UF membrane. Similar removal levels were achieved for turbidity (99.72%). The average COD removal was 97.3% resulting in an effluent with COD ranging between 8–32 mg/L. However, relatively low total nitrogen removal (TN) was achieved with a most likely mechanism for nitrogen removal nitrogen assimilation in the biomass. Heavy metal removals were very high: Pb and Ni were removed completely, indicating that these two metals were in particulate form, while Cr and Cu were removed by 89% and 49%, respectively. Combination of MBR and RO provided a superb quality effluent devoid of heavy metals and with very low organic matter concentration (DOC level below 4 mg/L). Yet, TN removal was not complete, resulting in a TN concentration around or less than 20 mg/L.