Integrated Membrane Bioreactor Research Articles

The effect of autochthonous metal ions and humic substances on landfill leachate ozonation: Reactive oxygen species and 3D fluorescence analysis

This study investigated the ozonation process for landfill leachate treatment, focusing on the impact of autochthonous metal ions (Fe3+, Cu2+, Mn2+, Mg2+) and humic substances on the degradation of pollutants. Our findings revealed that the presence of these metal ions significantly enhanced the generation of hydroxyl radicals (OH), especially for Fe3+, demonstrating the highest catalytic activity. However, the humic substance attenuated the signals of reactive oxygen species (ROS), particularly the superoxide radical (O2−) in the presence of Cu2+ and Mn2+. These suggested that metal ions could complex with humic substances and further inhibit ROS production. Despite this inhibition, Fe3+ maintained its ROS-generating capacity even in the presence of humic substances, indicating its potential as a robust catalyst in landfill leachate. Batch tests further demonstrated that Fe3+ had the most positive effect on the degradation of sodium humate, as evidenced by a significant reduction in fluorescence regional integration (FRI) values. An integrated membrane bioreactor (MBR) and ozonation system were conducted, which firstly processed activated sludge treatment in the MBR and then pumped into the ozonation system via a peristaltic pump. After ozonation, the leachate overflowed back into the MBR for further treatment, creating a closed-loop system. It was observed that there was a significant reduction in humic substances, with a decrease of 96.31% in the FRI. Parallel factor analysis (PARAFAC) results corroborated these findings, which indicated a marked reduction in the abundance of humic-like substances C-BO-1 and C-BO-4 during the 17 days treatment period. This study revealed the pivotal role of microorganisms, ROS, metal ions, and humic substances in the treatment of landfill leachate. The metal ions presented in the leachate were confirmed to produce ROS during the ozonation process. However, a significant quantity of humic-like substances reduced the reactive ROS through complexation and consumption reactions. Simultaneously, microorganisms in the MBR system consumed humic substances such as C-BO-1 and C-BO-4, which promoted the degradation of contaminants in the landfill leachate. These insights provided implications for optimizing ozonation processes in leachate management, potentially leading to more efficient and environmentally sustainable waste disposal practices.

Multi-Objective Optimization Based on Simulation Integrated Pareto Analysis to Achieve Low-Carbon and Economical Operation of a Wastewater Treatment Plant

It is essential to reduce carbon emissions in wastewater treatment plants (WWTPs) to achieve carbon neutrality in society. However, current optimization of WWTPs prioritizes the operation cost index (OCI) and effluent quality index (EQI) over greenhouse gas (GHG) emissions. This study aims to conduct a multi-objective optimization of a WWTP, considering GHG emissions, EQI, and OCI. The anaerobic-anoxic-oxic integrated membrane bioreactor (AAO-MBR) process in an actual WWTP was selected as a typical case, tens of thousands of scenarios with combinations of six operational parameters (dissolved oxygen (DO), external carbon resource (ECR), poly aluminum chloride (PAC), internal reflux ratio (IRR), external reflux ratio (ERR), and sludge discharge (SD)) were simulated by GPS-X software (Hydromantics 8.0.1). It was shown that ECR has the greatest impact on optimization objectives. In the optimal scenario, the main parameters of ATDO, MTDO, IRR, and ERR were 0.1 mg/L, 4 mg/L, 50%, and 100%, respectively. The EQI, OCI, and GHG of the best scenario were 0.046 kg/m3, 0.27 ¥/m3, and 0.51 kgCO2/m3, which were 2.1%, 72.2%, and 34.6% better than the current situation of the case WWTP, respectively. This study provides an effective method for realizing low-carbon and economical operation of WWTPs.

Environmental impact assessment via life cycle analysis on ultrafiltration membrane fabricated from polyethylene terephthalate waste to treat microalgal cultivation wastewater for reusability

The current study had conducted the life cycle analysis (LCA) to assess the environmental impact of microalgal wastewater treatment via an integrated membrane bioreactor. The functional unit selected for this analysis was 1 kg of treated microalgal wastewater with contaminants eliminated by ultrafiltration membrane fabricated from recycled polyethylene terephthalate waste. Meanwhile, the applied system boundary in this study was distinguished based on two scenarios, namely, cradle-to-gate encompassed wastewater treatment only and cradle-to-cradle which included the reutilization of treated wastewater to cultivate microalgae again. The environmental impacts and hotspots associated with the different stages of the wastewater treatment process had clearly elucidated that membrane treatment had ensued the highest impact, followed by microalgal harvesting, and finally cultivation. Among the environmental impact categories, water-related impact was found to be prominent in the following series: freshwater ecotoxicity, freshwater eutrophication and marine ecotoxicity. Notably, the key performance indicator of all environmental impact, i.e., the global warming potential was found to be very much lower at 2.94 × 10−4 kg CO2 eq as opposed to other literatures reported on the LCA of wastewater treatments using membranes. Overall, this study had proffered insights into the environmental impact of microalgal wastewater treatment and its stimulus for sustainable wastewater management. The findings of this study can be instrumental in making informed decision for optimizing microalgal wastewater treatment and reutilization assisted by membrane technology with an ultimate goal of enhancing sustainability.

Treatment of Membrane Cleaning Wastewater from Thermal Power Plant Using Membrane Bioreactor.

An integrated membrane bioreactor (MBR) with synthetic RO membrane cleaning wastewater from a thermal power plant was used to study the long-term operating characteristics, membrane fouling, and cleaning of membrane fouling. The results show that the MBR had a great removal effect on mainly an organic pollutant (citric acid) with an average of 98.4% rejection, and the concentration of organics in the effluent also achieved “Discharge standard of pollutants for municipal wastewater treatment plant” (GB12/599-2015). The optimal operating conditions were as follows: the membrane flux was 8 L/(m2·h); the hydraulic retention time (HRT) was 4 h; the sludge retention time (SRT) was 15 d, and the pH value was 6~7. A membrane fouling analysis showed that the resistance of the cake layer and the concentration polarization were the main components of membrane fouling. When the specific flux (SF) decreased to 10 L/(h·m2 mH2O), the membrane module was cleaned by tap water and then soaked in 0.05 wt% hydrochloric acid (HCl) and 3000 mg/L sodium hypochlorite (NaOCl) for 1 h and 3 h, respectively. Finally, the membrane flux could be recovered to 84.9% compared to the new membrane.

Design of an integrated membrane bioreactor process for effective and environmentally safe treatment of highly complex coffee industrial effluent

Food and beverage industries produce huge quantities of wastewater every day, with the coffee industry being one of the largest producers of effluents that pose grave environmental challenges due to high organic loading rate, strong odor and color. In the present study, the authors have investigated the performance of an integrated membrane bioreactor (IMBR) system using a combination of a biological process with side-steam ultrafiltration (UF) and subsequently reverse osmosis (RO) for the treatment of coffee industrial effluent. A significant reduction in chemical oxygen demand (COD) from 20,000 to 40 mg/L and turbidity from 1100 formazin attenuation unit (FAU) to 0 FAU, was achieved along with a considerable reduction in conductivity by 94 % (1.5 to 0.09 mS/cm) and total dissolved solids (TDS) by 76 %. The results revealed significant potential for meeting the acceptable range of parameters for safe disposal as specified by the central pollution control board (CPCB), while the recovered water was of a quality suitable enough for industrial reuse. A scale-up ratio of 10 from 2 L to 20 L in effluent batch size showed reproducible performance with pollutant diminution getting accelerated after 15 days to exhibit a significant removal of all pollutants, which emphasizes the effectiveness of the IMBR technology in meeting the environmental safety norms. This study reports for the first time 100 % separation of turbidity, color, and odor along with 99 % COD removal while successfully processing coffee industrial effluent. An economic estimate of a 1000 L/h capacity system confirms the commercial viability of the (IMBR) configuration.

A miniaturized air-lift membrane bioreactor for decentralized sewage treatment

Abstract In recent years, with the rapid development of rural economy and the improvement of living standards of local residents, the rural sewage discharge tends to concentrate and increase in amount, leading to growing concentration on the issue of rural sewage discharge and reuse. Nevertheless, the progress of sewage treatment has relatively been slow due to the backward level of technical management. In this study, a set of rural decentralized integrated membrane bioreactor system is developed in order to satisfy rural domestic sewage's characteristic of decentralization, including anaerobic tank, membrane bioreactor, clean water tank, aeration fan, suction pump and isolation plate. This invention possesses both technological advantages of the original membrane bioreactor and convenient operation which can be used to purify and to treat the domestic sewage of the scattered households, improving the flexibility of the sewage treatment. MBR equipment process flow chart Refluxed pipe of mixture and sludge Aerator ipe Outlet pipe Intake ipe Regulating pool Anaerobic pool Anoxic pool Aerobic pool Equipment room Figure Schematic diagram of construction Concri cfontmd Oto a rrm vrtlo, Lift 1 eg laI o i lLi) Pn iI I'll wellil, . Figure 2

Evaluation of advanced oxidation processes (AOPs) integrated membrane bioreactor (MBR) for the real textile wastewater treatment

A novel submerged membrane bioreactor integrated with ozonation and photocatalysis has been developed to treat the real textile wastewater and study the fouling behaviour. This study evaluates the performance efficiency in pilot-scale for the three reactors such as membrane bioreactor, ozonised membrane bioreactor and further clubbed with photocatalysis. The membrane filtration consists of polyvinilidine difluoride hollow fibre membrane module having pore size 0.1 μm. Tungsten oxide, a visible photocatalyst was made into spongy alginate beads and used in photocatalytic reactor. The photocatalyst dose has been optimised as 500 mg/L. About 10% membrane filterability ratio has been achieved by integrating ozone with MBR with the maximal ozone dosage of 5 g/h. It showed better removal efficiency in colour and chemical oxygen demand of 94% and 93% respectively. The biodegradability efficiency also was enhanced from 0.2 to 0.4 with optimised ozone dosage (5 g/h). The study on reversible and irreversible fouling has been done to understand the fouling nature. The important analysis such as microbial community and scanning electron microscopy analysis were done to study the biofouling and extent of fouling after filtration. The treatability studies implemented for textile wastewater showed that integrated MBR systems are suitable in meeting the discharge norms prescribed by the Indian statutory body in terms of chemical oxygen demand, colour and total suspended solids.

Development of integrated membrane bioreactor and numerical modeling to mitigate fouling and reduced energy consumption in pharmaceutical wastewater treatment

This work focus to alleviate the fouling in Membrane bioreactor (MBR) by integrating electrooxidation, adsorptive cake, bio-film carriers and ozonation referred as Integrated Moving Bed Bioreactor (IMBBR). The total organic carbon (TOC), Chemical Oxygen Demand (COD) and Total Dissolved Solids (TDS) removal were observed as above 95%, 95% and 70% at 300 kPa with the flux increase in 35%. The numerical model was developed which proved less fouling which was in agreement with Scanning electron microscopy (SEM) and Liquid Chromatography and Mass Spectroscopy (LCMS). This study showed less energy consumption without the problem of filamentous bulking.

Sensitivity and uncertainty analysis of an integrated ASM2d MBR model for wastewater treatment

An integrated membrane bioreactor (MBR) model was previously proposed and tested. The model provides a comprehensive and detailed description of the nitrogen biological removal processes with respect to up-to-date literature. This paper presents a sensitivity and uncertainty analysis aimed at identifying the key factors affecting the variability of the model predictions. The Standardized Regression Coefficients (SRC) method was adopted for the sensitivity analysis. The uncertainty analysis was employed by running Monte Carlo simulations by varying only the value of the key factors affecting the model outputs. The sensitivity analysis combined with the uncertainty analysis applied here enabled to gain useful insights about the robustness of the model. By means of the SRC method 45 model factors (of 122) were selected as important. The results obtained here allowed to investigate the advantage of a detailed description of the nitrogen transformation bioprocesses (nitrification/denitrification) in terms of model accuracy and uncertainty bandwidth. The model allows to simulate the intermediate product during nitrification/denitrification, thus providing the possibility to control the nitrogen compounds that favour the formation of nitrous oxide.

An integrated membrane bioreactor system with iron-dosing and side-stream co-fermentation for enhanced nutrient removal and recovery: System performance and microbial community analysis

An integrated membrane bioreactor (MBR) system was developed for enhanced nutrient (N and P) removal and effective P recovery in wastewater treatment. The system consisted of an iron-dosing MBR and side-stream fermentation for P removal and recovery and side-stream denitrification for N removal. Around 98.1% of the total phosphorus (TP) in wastewater was removed by ferric iron-induced precipitation and membrane filtration in the aerobic MBR, and nearly 53.4% of the TP could be recovered via anaerobic fermentation from the MBR sludge. In addition, the fermenter that allowed acidogenic co-fermentation with food waste provided sufficient soluble organics for biological denitrification, and an overall 91.8% total N removal was achieved through the side-stream denitrification. High-throughput sequencing was applied to analyse the microbial communities in the integrated system, and important functional bacteria were identified for nitrification, denitrification, acidogenic fermentation and dissimilatory iron reduction through the different components of the system.

Conceptual design optimization of an integrated membrane bioreactor system for wastewater treatment

This paper suggests an efficient optimization approach for the design of an integrated membrane bioreactor (MBR) system. Therefore, conceptual design studies to find optimal design conditions were performed with different constraints for the wastewater treatment using a mathematical modeling method. The integrated MBR system is composed of two anoxic tanks, two aerobic tanks, and one immersed membrane tank (Janus, 2013; Janus and Ulanicki, 2016). For the design of the system, the optimal process configurations, reactor volumes, and flow rates of each stream must be decided reasonably. Especially for the decision of the optimal process configurations, binary variables are generally employed as optimization decision variables for the mathematical modeling. Hence, a mixed integer nonlinear programming (MINLP) technique can be generally used to simultaneously determine the optimal design and operating conditions including process configurations. But if the MINLP problems are formulated as highly nonlinear dynamic equations, the optimal values of binary variables may sometimes be difficult to be properly decided. Thus, this paper introduces (1) the efficient optimization approach to solve the MINLP problems by parameterizing the binary variables leading to the reduction of the nonlinearity of the model, and (2) its applications to the conceptual designs of the integrated MBR system.

A comprehensive integrated membrane bioreactor model for greenhouse gas emissions

A comprehensive integrated membrane bioreactor (MBR) model for wastewater treatment is here proposed. The model quantifies the main biological and physical processes. The model describes the biological removal of organic matter, nitrogen and phosphorus including greenhouse gases (carbon dioxide, CO2 and nitrous oxide, N2O). The model takes into account the following main innovative aspects jointly: i. Two-step nitrification process; ii. N2O formation due to ammonia-oxidizing bacteria as a product of the hydroxylamine oxidation (NH2OH) and of the nitrite (NO2−) reduction; iii. Soluble microbial product (SMP) formation/degradation due to microbial growth and endogenous respiration; iv. Interlink between SMP and membrane fouling. The model was calibrated by employing a detailed calibration protocol and data from a University Cape Town (UCT) – MBR pilot plant. The key processes contributing to the N2O formation were properly described (total efficiency related to the calibrated model equal to 0.55). Results suggested that the incomplete hydroxylamine oxidation and the heterotrophic denitrification were the predominant processes influencing the N2O production. The model was able to describe the membrane fouling as demonstrated by the high efficiency (0.92) for the resistance state variable. This result confirms the importance in the modelling approach of considering both biological and physical processes jointly.

A novel gas separation integrated membrane bioreactor to evaluate the impact of self-generated biogas recycling on continuous hydrogen fermentation

A Gas Separation Membrane Bioreactor (GSMBR) by integrating membrane technology with a continuous biohydrogen fermenter was designed. The feasibility of this novel configuration for the improvement of hydrogen production capacity was tested by stripping the fermentation liquor with CO2- and H2-enriched gases, obtained directly from the bioreactor headspace. The results indicated that sparging the bioreactor with the CO2-concentrated fraction of the membrane separation unit (consisting of two PDMS modules) enhanced the steady-state H2 productivity (8.9–9.2 L H2/L-d) compared to the membrane-less control CSTR to be characterized with 6.96–7.35 L H2/L-d values. On the other hand, purging with the H2-rich gas strongly depressed the achievable productivity (2.7–3.03 L H2/L-d). Microbial community structure and soluble metabolic products were monitored to assess the GSMBR behavior. The study demonstrated that stripping the bioH2 fermenter with its own, self-generated atmosphere after adjusting its composition (to higher CO2-content) can be a promising way to intensify dark fermentative H2 evolution.

Increasing of leachate quality using an integrated aerobic membrane bioreactor

The aim of this study was the increasing of leachate quality using integrated membrane bioreactor (MBR). The reactor was fed with treated leachate with overall 70-1360 mg/l chemical oxygen demand (COD). The analysis of COD, biochemical oxygen demand (BOD 5 ), total suspended solids (TSS), and total dissolved solids (TDS) were performed in feed and filtrate, whenever the system reached steady state twice a week for 6 months. In all loading rate, BOD 5 concentration was less than the standard limit. The removal efficiency of COD in all experiments was up to 80%. Up to 99% of solids, which may mainly include colloidal solids, were removed with micropore membrane. There was no significant difference between TDS concentration in feed and filtrate. It was concluded that MBR is a versatile technology with high throughput and can treat compost leachate below standard limit if used after appropriate processes.

Sensitivity and uncertainty analysis of an integrated membrane bioreactor model

Sensitivity and uncertainty analysis, although can be of primarily importance in mathematical modelling approaches, are scarcely applied in the field of membrane bioreactor (MBR). An integrated mathematical model for MBR is applied with the final aim to pin down sources of uncertainty in MBR modelling. The uncertainty analysis has been performed combining global sensitivity analysis (GSA) with the generalized likelihood uncertainty estimation (GLUE). The model and methodology were applied to a University Cape Town pilot plant. Results show that the complexity of the modelled processes and the propagation effect from the influent to the effluent increase the uncertainty of the model prediction. It was found that the uncertainty of nitrogen and phosphorus model outputs increases from the first reactor-section plant to the last. Results show also that the GSA-GLUE methodology is a valid tool for uncertainty assessment for MBR modelling. Furthermore, the GSA-GLUE allows to identify the most critical processes/plant sections and the key sources of uncertainty where attention should be paid in view of model predictions improvement.

Heavy Metal Removal by Electrocoagulation Integrated Membrane Bioreactor

This study investigates the performance of electrocoagulation integrated membrane bioreactor (EMBR) in treating synthetic wastewater enriched with heavy metals (Cu, Cr, and Zn). This hybrid system was compared with a conventional membrane bioreactor (MBR). The results suggest that it is superior to conventional MBR in terms to chemical oxygen demand removal, flux improvement, fouling reduction, and metal removal. The metal removal efficiencies in both MBR and EMBR followed the sequence Cr > Cu > Zn. The average removal efficiencies in MBR were 60.90, 53.24, and 48.22% for Cr, Cu, and Zn, respectively, while for the EMBR 98.60, 97.53, and 93.52% could be achieved, respectively. The mixed liquor suspended solids (MLSS) concentration was also found to affect the metal removal potential of the MBR. In MBR, metal removal and MLSS concentration showed significant relationship, while in EMBR, this correlation was found to be less. The specific energy consumption for removing each metal by EMBR was calculated and found to be 6.62, 6.94, and 6.69 kWh/kg removed for Cr, Zn, and Cu, respectively.

Potential of Integrated Membrane Bioreactor in Batik Dye Degradation - A Review

The objectives of this study are mainly focusing on reviewing the potential of membrane bioreactor application in Batik dyes degradation and to identify the factors contributing to the permeability and selectivity of a membrane-coupled bacteria reactor. It is evidently that integrating membrane technology with biological reactors for the treatment of textile dyeing wastewaters has led to the development of three generic membrane processes within bioreactors: for separation and recycle of solids, for bubble-less aeration of the bioreactor, and for extraction of priority organic pollutants from hostile textile dyeing wastewaters. Thus, installation costs and usable floor area of the infrastructure are saved, due to the separation unit of MBR replaced the sedimentation basin that is used in current practice. It is well recognized that east coast states in Malaysia such as Kelantan and Terengganu are the main producers of “Batik” industries in which create a huge contribution to Malaysia textile economy development due to high demands from local and abroad. Batik textile wastewater is a complex and consist highly variable mixture of many polluting substances including dye. Existence of dyes in the wastewater plays a major issue and has raised significant concerns. Thus, selection of microorganism and the separation processes of the membrane bioreactor are vital to be evaluated towards an achievable productivity and efficient process separation. These are depended on several factors which include degradation of dye, temperature, retention time, pH and concentration of the textile wastewater.

Global sensitivity analysis in wastewater applications: A comprehensive comparison of different methods

Three global sensitivity analysis (GSA) methods are applied and compared to assess the most relevant processes occurring in wastewater treatment systems. In particular, the Standardised Regression Coefficients, Morris Screening and Extended-FAST methods are applied to a complex integrated membrane bioreactor (MBR) model considering 21 model outputs and 79 model factors. The three methods are applied with numerical settings as suggested in literature. The main objective considered is to classify important factors (factors prioritisation) as well as non-influential factors (factors fixing). The performance is assessed by comparing the most reliable method (Extended-FAST), by means of proposed criteria, with the two other methods. In particular, similarity to results obtained from Extended-FAST is assessed for sensitivity indices, for the ranking of sensitivity indices, for the classification into important/non-influential factors and for the method's ability to detect interaction among factors and to provide results in a reasonable time.It was found that the computationally less expensive SRC method was applied outside its range of applicability (R2) = (0.3–0.6) < 0.7. Still, the SRC produced a ranking of important factors similar to Extended-FAST. For some variables significant interactions among the factors were revealed by computing the total effect indices STi using Extended-FAST. This means that to obtain reliable variance decomposition and to detect and quantify interactions among the factors, the use of the Extended-FAST is recommended. Regarding the comparison between Morris screening and Extended-FAST a poor agreement was found. In particular, the Morris screening overestimated the number of both important and non-influential factors compared to Extended-FAST for the analysed case study.

Integrated Membrane Bioreactor for Water Quality Control in Marine Recirculating Aquaculture Systems

The aquaculture live feed organisms Acartia tonsa (a calanoid copepod, experiment 1) and Brachionus “Cayman” (a rotifer, experiment 2) were cultivated in marine recirculating aquaculture systems (RAS), respectively. The pilot plant was built as a combination of conventional RAS (cRAS) and as a modified RAS which implemented an ultrafiltration membrane bioreactor (MBR) for the removal of fine suspended solids and colloidal particles as part of the treatment system (mRAS). The two treatment schemes were connected to the same biofilter (a moving bed bioreactor). In the first experiment, the membrane was operated with no extraction of concentrate, and hydraulic retention time (HRT) of 6 hours (i.e., water exchange in the cultivation tanks of 4 times per day). In the second experiment, the membrane was operated with daily extraction of concentrate, and HRT of 12 hours. Results show that the MBR option is more efficient in removing particles from the recycle stream than conventional RAS. However, the impact this has on the number of particles in the live feed cultivation tanks is not readily apparent based on particle analysis. The amount of suspended solids added during feeding exceeds the amount removed in the recycle system. This requires a higher recirculation rate and different membrane operating conditions.

Characterisation of RO fouling in an integrated MBR/RO system for wastewater reuse

Membrane filtration has gradually gained acceptance as the preferred pre-treatment for reverse osmosis (RO). In this paper, an integrated membrane bioreactor (MBR)/RO system for wastewater reuse treating real sewage water has been evaluated and the RO fouling has been characterised. The MBR achieved low values of organic matter, total nitrogen, PO(4)(3-), total organic carbon, turbidity and conductivity. Filtration with two different RO commercial membranes was performed after the MBR pre-treatment and the same average fouling rate (0.08 bar day(-1)) was noted. These results gained from the characterisation of the high quality MBR/RO permeate show its potential for water reuse. Inorganic precipitation appears to be the predominant form of fouling in the RO membranes. Calcium phosphate and alumino-silicates were identified by a scanning electron microscope combined with an energy dispersive X-ray and polysaccharides, amide and aliphatic structures were detected with attenuated total reflection infrared microspectroscopy.