Membrane Bioreactor Design Research Articles

Effect of biomass concentration in membrane bioreactor design on alpha factor for two large pilot systems: Case study of mechanical surface aeration and air insufflation system

In the literature, the studies on wastewater treatment process have shown a great interest in aeration system, most of them were performed on small pilot lab-scale. However, it still an important need to provide useful information aiming at reducing the operating costs and providing decision support to choose aeration devices. Considering that membrane bioreactors operating with high biomass concentrations up to 20–30 g of suspended solids (SS) per liter, the present study was carried out on a larger pilot lab-scale ( ± 500 l) of insufflation system and mechanical surface aeration on the same fresh sludge with concentration varying between 4.6 and 19.8 g/l. The comparison with literature data shows good correspondence with values obtained with our insufflation system but a great difference from values obtained in a mechanical system. In addition, this research provides a better insight on the calculation method that can be used to estimate the critical parameters of the oxygen transfer, and analyses the feasibility of air diffusion substitution by surface aeration system of Louvain La Neuve wastewater treatment plant of 13000 population equivalent. This extrapolation proved that a saving of ± 50,000 € per year can be achieved by choosing surface aeration rather than aeration by air insufflation.

Superior performance of a membrane bioreactor through innovative in-situ aeration and structural optimization using computational fluid dynamics.

The optimization of membrane bioreactors (MBRs) involves a critical challenge in structural design for mitigation of membrane fouling. To address this issue, a three-dimensional computational fluid dynamics (CFD) model was utilized in this study to simulate the hydrodynamic characteristics of a flat sheet (FS) MBR. The optimization of the membrane module configuration and operating conditions was performed by investigating key parameters that altered the shear stress and liquid velocity. The mixed liquor suspended solids (MLSS) concentration was found to increase the shear stress, leading to a more uniform distribution of shear stress. By optimizing the appropriate bubble diameter to 5mm, the shear stress on the membrane surface was optimized with relatively uniform distribution. Additionally, extending the side baffle length dramatically improved the uniformity of the shear stress distribution on each membrane. A novel in-situ aeration method was also discovered to promote turbulent kinetic energy by 200 times compared with traditional aeration modes, leading to a more uniform bubble streamline. As a result, the novel in-situ aeration method demonstrated superior membrane antifouling potential in the MBR. This work provides a new approach for the structural design and optimization of MBRs. The innovative combination of the CFD model, optimization techniques, and novel in-situ aeration method has provided a substantial contribution to the advancement of membrane separation technology in wastewater treatment.

Interfacial interaction between ellipsoidal particle and membrane surface with random topographies

Modeling rough surfaces has received attention as it can facilitate understanding of colloidal systems. This work comprehensively discussed a facile approach for simulating the surface morphologies of ellipsoidal particles and membrane surfaces three-dimensionally. The fractal geometry theory was applied to construct a randomly rough surface. The assessment approach involving the surface element integral (SEI) method based on the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was proposed to quantify the interfacial interaction between the constructed ellipsoidal particle and membrane surface. The simulated results demonstrated that the total interaction energy created between the particle and membrane surface was intensified by enlarging the particle and elevating the fractal dimension of the surface. The fractal roughness and orientation angle of the particle negatively affected the total interfacial energy between the particle and membrane surface. Moreover, the shape of the particle was found to have a profound effect on the total interaction energy. The new method has a wide range of potential applications in membrane bioreactor design and operation since it can predict the interaction of sludge flocs and membrane surface.

Membrane BioReactor (MBR) Activated Sludge Surrogate Alternatives Carboxymethyl Cellulose and Xanthan Gum: A Statistical Analysis and Review.

Membrane Bioreactors (MBR) combine traditional biological treatments such as Activated Sludge (AS) with a membrane-based filtration process to extract suspended and organic solids. MBR operation involves high shear rates near the membrane surface due to the high crossflow velocity, which complicates any simulation process from a hydrodynamic point of view. In this regard, the viscosity as a function of total suspended solids (TSS) plays an essential role in characterizing and modeling the behavior of activated sludge (AS). However, AS has an intransparency property that prevents experimental measurements (i.e., velocity profiles) commonly associated with optical techniques from being peformed. In light of this limitation, two polymeric compounds, carboxymethyl cellulose (CMC) and xanthan gum (XG), are considered here in order to explore the possibility of mimicking the rheological behavior of AS. These compounds are commonly used in the food industry as food thickeners, and their rheological behavior is supposedly well defined in the literature. In this work, we reviewed the viscosity behavior of these compounds through their reported flow behavior and consistency indexes. It was found that the rheological properties of these two polymers differ depending on the chemical manufacturer, rheometers, and measurement protocols involved. Different curves (shear rate vs. viscosity/shear stress) are obtained, as each device and procedure seem to modify the polymer structure. Therefore, a statistical analysis was performed based on the flow and consistency indexes using different concentrations and temperatures reported in experimental data. Several insights regarding CMC, XG, and AS performance were obtained, including a better relationship with concentration than with temperature or certain exponential-based performances, which can support further MBR design and operational decision-making.

Simultaneous Enzymatic Cellulose Hydrolysis and Product Separation in a Radial-Flow Membrane Bioreactor.

Hydrolysis is the heart of the lignocellulose-to-bioethanol conversion process. Using enzymes to catalyze the hydrolysis represents a more environmentally friendly pathway compared to other techniques. However, for the process to be economically feasible, solving the product inhibition problem and enhancing enzyme reusability are essential. Prior research demonstrated that a flat-sheet membrane bioreactor (MBR), using an inverted dead-end filtration system, could achieve 86.7% glucose yield from purified cellulose in 6 h. In this study, the effectiveness of flat-sheet versus radial-flow MBR designs was assessed using real, complex lignocellulose biomass, namely date seeds (DSs). The tubular radial-flow MBR used here had more than a 10-fold higher membrane surface area than the flat-sheet MBR design. With simultaneous product separation using the flat-sheet inverted dead-end filtration MBR, a glucose yield of 10.8% from pretreated DSs was achieved within 8 h of reaction, which was three times higher than the yield without product separation, which was only 3.5% within the same time and under the same conditions. The superiority of the tubular radial-flow MBR to hydrolyze pretreated DSs was confirmed with a glucose yield of 60% within 8 h. The promising results obtained by the novel tubular MBR could pave the way for an economic lignocellulose-to-bioethanol process.

Мембранные биореакторы: опыт применения в зарубежных странах

This article addresses advanced methods of wastewater treatment, which presents an urgent global problem. The use of membranes or so-called membrane bioreactors (MBR) at treatment facilities comprises an efficient method of wastewater treatment. The characteristics of membrane designs along with their practical advantages and disadvantages are considered. Examples of using MBR at wastewater treatment plants in Germany, Italy and Sweden are examined. A recently developed MBR technology based on filtration through micro- or ultrafiltration membranes is gaining in popularity. In such technologies, the high quality of treated water is achieved due to the MBR design, which increases both the concentration of activated sludge in the bioreactor and its filtering capacity. Over 100 years of contemporary residential and industrial wastewater treatment, no other implemented technology has exhibited as many positive effects. Due to the wide range of available membranes and modules, suitable systems can be found for almost any type of water treatment application. In addition, these membranes are compact, which becomes an advantage when clearing areas for new construction or when the expansion of a wastewater treatment plant is limited.

Comparing the performance of the conventional and fixed-bed membrane bioreactors for treating municipal wastewater.

Membrane bioreactor (MBR) is relatively a new technology in wastewater treatment. It can efficiently remove soluble and suspended organics. However, it may constantly encounter bio-fouling and cannot efficiently remove nutrient pollutants. These two deficiencies have motivated researchers to upgrade the design and operation of conventional MBR (CMBR). This study evaluates the performance of hybrid fixed bed MBR (FBMBR) treating real domestic wastewater in different operational conditions. It also compares the experimental results of FBMBR with the CMBR. For this purpose, two identical reactors are constructed as CMBR and FBMBR. Each module contains the net volume of 140L and is operated continuously in two aerobic (DO > 4mg/L) and anoxic (DO < 1mg/L) conditions with average organic loading rates (OLRs) of 0.58, 0.71 and 1.55 kgCOD/m3d. The pore sizes of flat sheet membranes are 0.2-0.8μm with total surface area of 1.4m2 per module. The experimental results revealed that the removal efficiencies of BOD, COD and TSS are above 95 % in both CMBR and FBMBR in all operating conditions. However, fouling occurs with lower rates in FBMBR. The growing rate of transmembrane pressure (TMP) in aerobic condition is 1.7mBar/day in CMBR, while it reduces to 1.2mBar/day for FBMBR in solid retention time (SRT) of 75 days and OLR of 0.58 and 0.71 kgCOD/m3d. In anoxic condition with SRT of 100 days and OLR of 1.55 kgCOD/m3d, the TMP in FBMBR is 59 % of CMBR. In addition, total nitrogen (TN) removal is between 12 % (aerobic) and 27 % (anoxic) in CMBR, while it is between 25 % (aerobic) and 49 % (anoxic) in FBMBR. Total phosphorous (TP) removal also ranges between 50 and 66 % in CMBR, while it is between 51 and 86 % in FBMBR. Consequently, using hybrid systems of FBMBR can reduce membrane fouling rate and improve nutrient removal efficiency in comparison with CMBR. This approach can reinforce the biological treatment efficiency and preserve permeate quality in higher OLRs or in lower DO level.

Particle size distribution as a major characteristic of domestic wastewater: implications for the modeling and design of membrane bioreactors

AbstractThis study reviews the evolution of the concept and the methodology of particle size distribution (PSD) analysis for sewage. Evaluation of experimental data indicated that the analytical approach started with an empirical identification of soluble, colloidal and supra‐colloidal organic matter. Then, it evolved into a sequential filtration and ultrafiltration methodology, yielding results useful enough to be an integral complement of respirometric chemical oxygen demand (COD) fractionation based on biodegradation characteristics. Default values could be defined for the distribution of COD fractions in terms of both size and biodegradation characteristics, which practically showed similar profiles, suggesting that PSD of COD could be directly used for model evaluation and design of activated sludge configurations. Size distribution of COD in sewage should be regarded as a prerequisite for activated sludge systems with a membrane module, mainly to assess the fate of COD fractions that would be entrapped and recycled back to the reactor by membrane filtration. © 2020 Society of Chemical Industry

MBR treatment of leachates originating from waste management facilities: A reference study of the design parameters for efficient treatment

The main objective of the study was to define the interaction between the solid retention time (SRT) and the contaminant loading rate on a membrane bioreactor's efficacy in removing contaminants frequently detected (chemical oxygen demand (COD), NH4+, total phosphorus and metals) above the discharge criteria in waste-originating leachates. The rates and coefficient calculated from this study's experimental data can be used for the design of membrane bioreactor treating wastewaters, even beyond the scope of this experiment. Over a period of 152 days, SRTs of 28 and 47 days and HRTs of 13, 25, 36 and 52 h were studied using a real leachate with a constant composition. Results showed that membrane bioreactors can efficiently treat >1850 mg COD L−1 d−1 of highly to moderately biodegradable COD, with the SRT having no significant impact on the removal of recalcitrant COD. Overall ammonium removal rates of >740 mg NH4–N L−1 d−1 can be achieved as long as a residual alkalinity of 200 mg CaCO3 L-1 and an adequate dissolved oxygen concentration (6–7 mg L−1) are both maintained. Overall phosphorus removal rates are independent of the phosphorus loading rate. However, the highest overall phosphorus removal rate (39 ± 2 mg P per g of total suspended solids) was obtained at the lowest SRT (28 days) due to an increased extracellular polymeric substance production. Finally, membrane bioreactor's metal removal capacity is mostly dependent on the metals' affinity to both the leachate's recalcitrant COD as well as sludge concentrations.

Current Status and Future Prospects of Membrane Bioreactors (MBRs) and Fouling Phenomena: A Systematic Review

AbstractMembrane bioreactors (MBRs) have been widely used for municipal and industrial wastewater treatment around the world due to their advantages, which include higher efficiency, smaller footprint, and lower sludge production over other conventional activated sludge (CAS) processes. However, membrane fouling that results from physicochemical interactions between the membrane and the components of the mixed liquor still remains the most challenging matter preventing the broad application of MBR technology. Recently, a considerable number of experimental and modelling investigations have been conducted concerning MBRs and membrane fouling. Despite the development of low‐fouling membrane systems, more research and engineering activities with a focus on surface modification, wastewater specifications, pre‐treatment and treatment conditions, and efficient fouling control and remedy strategies are still needed to minimize the probability of the occurrence of fouling. It is vital to investigate important aspects of the characterization and mechanisms of the fouling phenomenon to find reliable and long‐term solutions. This review provides a detailed survey of the main aspects of the MBR processes, configurations, advantages and disadvantages, fouling phenomenon, and fouling control strategies in MBRs. Past research and engineering activities in this area are critically reviewed such that pros and cons of recent developments in fouling inhibition and mitigation approaches are also discussed. The main practical and theoretical challenges for the effective utilization of MBRs in various municipal and industrial sectors are then addressed. At the end, we offer useful practical guidelines and recommendations for the better design and operation of MBRs in industrial and public communities.

Ceramic membrane fouling by dissolved organic matter generated during on-line chemical cleaning with ozone in MBR

Ceramic membrane bioreactor (MBR) has attracted increasing interest due to its high flux, long membrane life-span and excellent resistance to hash operation conditions. Although ozone has been used for chemical cleaning of ceramic membranes, it is still unclear about the role of dissolved organic matter (DOM) generated during on-line chemical cleaning with ozone in the development of membrane fouling in ceramic MBR. This study clearly revealed that the released DOM could considerably induce irreversible membrane fouling, and humic acid like-substances (HAL) with molecular weight (MW) of about 500 Da were mainly responsible for the observed membrane fouling. A strong positive relationship existed between the membrane fouling rate of supernatant and the rejection level of HAL, evidenced by a high correlation coefficient (R2) of 0.99. Meanwhile, the results also showed that biopolymers with MW greater than 10 kDa were easily rejected by the ceramic membranes used, leading to the development of membrane fouling. However, the high ozone concentration helped to reduce the generation of biopolymers. The organic fractions with MW less than 500 Da in the DOM (e.g. building blocks, low-MW acid and low-MW neutrals) could pass through the ceramic membranes used, i.e. their contributions to the observed membrane fouling could be considered insignificant. Consequently, it appeared from this study that membrane fouling associated with the DOM generated by ozone during on-line chemical cleaning should not be ignored in the design and operation of ceramic MBR towards long-term process sustainability.

Computer-Aided Design and Simulation of a Membrane Bioreactor for Produced Water Treatment

Membrane Bio Reactor (MBR) has been designed and simulation for the treatment of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Organic Carbon (TOC), Total Dissolved Solid (TDS) and Oil/ Grease in produced water at a capacity of 54.1778 kg/hr for removal of 95%-99% contaminants. The MBR design equations were developed using the law of conservation of mass to determine the dimensions and functional parameters. The developed performance equations were integrated numerically using fourth-order Runge-Kutta embedded in MATLAB computer program to determine the optimum range of values of the reactor functional dimensions and functional parameters. The effect of rate of energy supply per reactor volume and substrate specific rate constant on the capacity of the membrane bioreactor were investigated. Also, the effect of initial loading of substrate on Solid Retention Time (SRT) was also investigated. Results showed that kinetic parameters influenced the percentage removal of contaminants as Hydraulic Retention Time (HRT) and size of MBR decreased with increase in specific rate constant at fixed conversion of contaminants. Also, HRT and MBR size increased as the conversion of Chemical Oxygen Demand (COD) was increased, while increased in the ratio of energy supplied per volume resulted in decreased of MBR volume. The effect of initial loading of substrate on SRT showed that increased in substrate loading increased the retention time of the solid at fixed substrate conversion, while the conversion of substrate to microorganism increased as the solid retention time was increased. The increased in initial loading of substrate concentration increased the production of Mixed Liquor Suspended Solids (MLSS). Thus, the size of MBR required for the conversion of the investigated contaminants at the design percentage removal increased in the following order: oil/grease < TSS < TOC < TDS. The MBR volume, height and HRT were 1.10 and 5.29 m3; 0.98 and 4.68 m; and 1.38 and 6.62 at 95% and 99% respectively, while the SRT was 82.67 days.

Significance of membrane bioreactor design on the biocatalytic performance of glucose oxidase and catalase: Free vs. immobilized enzyme systems

Membrane separation of xylose and glucose can be accomplished via oxidation of glucose to gluconic acid by enzymatic glucose oxidase catalysis. Oxygen for this reaction can be supplied via decomposition of hydrogen peroxide by enzymatic catalase catalysis. In order to maximize the biocatalytic productivity of glucose oxidase and catalase (gluconic acid yield per total amount of enzyme) the following system set-ups were compared: immobilization of glucose oxidase alone; co-immobilization of glucose oxidase and catalase; glucose oxidase and catalase free in the membrane bioreactor. Fouling-induced enzyme immobilization in the porous support of an ultrafiltration membrane was used as strategy for entrapment of glucose oxidase and catalase. The biocatalytic productivity of the membrane reactor was found to be highly related to the oxygen availability, which in turn depended on the reactor configuration, hydrogen peroxide concentration and catalase origin. When glucose oxidase and catalase (from Aspergillus niger) were free in the membrane bioreactor a total biocatalytic productivity of 122mg gluconic acid/mg enzyme was obtained after five consecutive reaction cycles. The free enzymes showed superior performance compared to the immobilized systems as a result of limited substrate and product diffusion in the latter case.

Impact of sludge retention time on the fine composition of the microbial community and extracellular polymeric substances in a membrane bioreactor.

Membrane bioreactors (MBRs) are an advanced technology for wastewater treatment whose wide application has been hindered by rapid fouling of the membranes. MBRs can be operated with long sludge retention time (SRT), a crucial parameter impacting microbial selection in the reactor. This also affects filtration performance, since a major fouling agent are the extracellular polymeric substances (EPS). In this study, the impact of the SRT on the ecophysiology of the MBRs and, consequently, on membrane fouling was evaluated. A MBR was operated under a SRT of 60days followed by a SRT of 20days. A comprehensive analysis of the microbial community structure and EPS proteins and polysaccharide profiles of the mixed liquor and cake layer was carried out throughout both operation periods. The results of this study showed that the imposition of a shorter SRT led to a shift in the dominant bacterial populations. The mixed liquor and cake layer communities were very different, with Actinomycetales order standing out in the cake layer at SRT of 20days. Overall, higher EPS concentrations (particularly proteins) were found at this SRT. Furthermore, EPS profiles were clearly affected by the SRT: it was possible to correlate a group of soluble EPS proteins with the SRT of 60days, and a lower sludge age led to a lower diversity of polysaccharide sugar monomers, with an increase of glucose and galactose in the cake layer. This study improves our knowledge regarding the molecular reasons for fouling, which may contribute to improve MBR design and operation.

Effect of turbulence on fouling control of submerged hollow fibre membrane filtration

In this study, we investigated the effect of turbulence on hollow fibre membrane filtration in terms of membrane fouling performance experimentally. In particular, a special setup with a turbulence generator using a vibrating perforated plate was constructed in the laboratory. The setup enabled the hollow fibre membrane filtration to be carried out within a design ambient with targeted levels of turbulence without mean shears. The non-intrusive laser imaging approach of Particle Image Velocimetry (PIV) was used to quantify the characteristics of the turbulence ambient. Subsequently, by monitoring the rate of trans-membrane pressure (TMP) rise with constant permeate flux experiments using 4 g/L yeast feed suspensions, we obtained unique data sets that revealed the quantitative effects of turbulence on membrane fibre filtration, which are not available in the literature so far. Overall, the results indicated that the presence of turbulence moderated the membrane fouling and reduced the corresponding rate of TMP rise (dTMP/dt). Two key turbulence parameters, namely, turbulence kinetic energy (TKE) and eddy length scale, were found to relate to the membrane fouling reduction, with the rate of TMP rise generally decreasing when TKE or eddy length scale increases. In addition, there exists an optimum eddy length scale beyond which the eddy size (comparable to approximately ten times of the hollow fibre diameter in the present study) has no more influence on the fouling behaviour. A direct comparison between turbulence and membrane vibration for fouling control was also performed. The implications of the present results on the design of membrane bioreactors (MBRs) are discussed.

N-acyl homoserine lactone-mediated quorum sensing with special reference to use of quorum quenching bacteria in membrane biofouling control.

Membrane biofouling remains a severe problem to be addressed in wastewater treatment systems affecting reactor performance and economy. The finding that many wastewater bacteria rely on N-acyl homoserine lactone-mediated quorum sensing to synchronize their activities essential for biofilm formations; the quenching bacterial quorum sensing suggests a promising approach for control of membrane biofouling. A variety of quorum quenching compounds of both synthetic and natural origin have been identified and found effective in inhibition of membrane biofouling with much less environmental impact than traditional antimicrobials. Work over the past few years has demonstrated that enzymatic quorum quenching mechanisms are widely conserved in several prokaryotic organisms and can be utilized as a potent tool for inhibition of membrane biofouling. Such naturally occurring bacterial quorum quenching mechanisms also play important roles in microbe-microbe interactions and have been used to develop sustainable nonantibiotic antifouling strategies. Advances in membrane fabrication and bacteria entrapment techniques have allowed the implication of such quorum quenching bacteria for better design of membrane bioreactor with improved antibiofouling efficacies. In view of this, the present paper is designed to review and discuss the recent developments in control of membrane biofouling with special emphasis on quorum quenching bacteria that are applied in membrane bioreactors.

Energy efficiency in membrane bioreactors

Energy consumption remains the key factor for the optimisation of the performance of membrane bioreactors (MBRs). This paper presents the results of the detailed energy audits of six full-scale MBRs operated by Suez Environnement in France, Spain and the USA based on on-site energy measurement and analysis of plant operation parameters and treatment performance. Specific energy consumption is compared for two different MBR configurations (flat sheet and hollow fibre membranes) and for plants with different design, loads and operation parameters. The aim of this project was to understand how the energy is consumed in MBR facilities and under which operating conditions, in order to finally provide guidelines and recommended practices for optimisation of MBR operation and design to reduce energy consumption and environmental impacts.

Biological nitrogen and phosphorus removal in membrane bioreactors: model development and parameter estimation

Membrane bioreactors (MBR) are being increasingly used for wastewater treatment. Mathematical modeling of MBR systems plays a key role in order to better explain their characteristics. Several MBR models have been presented in the literature focusing on different aspects: biological models, models which include soluble microbial products (SMP), physical models able to describe the membrane fouling and integrated models which couple the SMP models with the physical models. However, only a few integrated models have been developed which take into account the relationships between membrane fouling and biological processes. With respect to biological phosphorus removal in MBR systems, due to the complexity of the process, practical use of the models is still limited. There is a vast knowledge (and consequently vast amount of data) on nutrient removal for conventional-activated sludge systems but only limited information on phosphorus removal for MBRs. Calibration of these complex integrated models still remains the main bottleneck to their employment. The paper presents an integrated mathematical model able to simultaneously describe biological phosphorus removal, SMP formation/degradation and physical processes which also include the removal of organic matter. The model has been calibrated with data collected in a UCT-MBR pilot plant, located at the Palermo wastewater treatment plant, applying a modified version of a recently developed calibration protocol. The calibrated model provides acceptable correspondence with experimental data and can be considered a useful tool for MBR design and operation.

ChemInform Abstract: Selection and Design of Membrane Bioreactors in Environmental Bioengineering

AbstractReview: 76 refs.

Operating Large Scale Membrane Bioreactors for Municipal Wastewater Treatment

During the last decade membrane bioreactor (MBR) technology has grown up to be state of the art in municipal wastewater treatment. Since 1999 the Erftverband has designed, tendered and commissioned three MBR for municipal wastewater treatment in Germany, with capacities from 3,000 to 45,000 m3/d. The Erftverband was one of the pioneers in the full scale application of the technology regularly hosted training and information workshops for plant designers and operators from all over the world.Operating Large Scale Membrane Bioreactors for Municipal Wastewater Treatment provides hands-on information on many aspects of MBR technology based on more than ten years of practical experience in the operation of MBR plants with hollow-fiber microfiltration units. It gives details on process configuration, investment and operation costs based on case studies and also in comparison to data from conventional activated sludge (CAS) treatment processes. The book contains the most recent research findings as Erftverband has been collaborating on many of the major European research projects dedicated to MBR technology.Actual process data from all treatment steps of the plants (mechanical pre-treatment, bioreactors, filtration, membrane cleaning) gives an insight into the long-term performance of the MBR plants and into the possible do's and dont's of full scale applications and the potential for further process optimisation. It is a good source of practical advice on tendering and construction, plant management and operation.Operating Large Scale Membrane Bioreactors for Municipal Wastewater Treatment is essential reading for practitioners and researchers, providing information on many aspects of MBR technology, including actual process data, graphs and pictures that illustrate the challenges of MBR design and operation.ISBN: 9781843393054 (Print)ISBN: 9781780401409 (eBook)