Previously, an electrochemical bandage (e-bandage) that uses a three-electrode system to produce hydrogen peroxide (H2O2) electrochemically on its working electrode was developed as a potential strategy for treating biofilms; it showed activity in reducing biofilms in an agar biofilm model. Xanthan gum-based hydrogel, including NaCl, was used as the electrolyte. While H2O2 generated at the working electrode in the vicinity of a biofilm is a main mechanism of activity, the role of the counter electrode was not explored. The goal of this research was to characterize electrochemical reactions occurring on the counter electrode of the e-bandage. Counter electrode potential varied between 1.2 and 1.5 VAg/AgCl; ∼125 µM hypochlorous acid (HOCl) was generated within 24 h in the e-bandage system. When HOCl was not produced on the counter electrode (achieved by removing NaCl from the hydrogel), reduction of Acinetobacter baumannii BAA-1605 biofilm was 1.08 ± 0.38 log10 CFU/cm2 after 24 h treatment, whereas when HOCl was produced, reduction was 3.87 ± 1.44 log10 CFU/cm2. HOCl inhibited catalase activity, abrogating H2O2 decomposition. In addition to H2O2 generation, the previously described H2O2-generating e-bandage generates HOCl on the counter electrode, enhancing its biocidal activity.

Oxygen and reactive oxygen species (ROS) produced during algal photosynthesis are important electron acceptors in photosynthetic algal microbial fuel cell (PAMFC) cathodes. In this study, spongy and petaline ZnO-NiO@rGO carbon felt cathodes were first fabricated through in situ ZnO-NiO growth and further modified with reduced graphene oxide (rGO) via electrodeposition and cyclic voltammetry reduction. The structural and electrochemical properties of the ZnO-NiO@rGO carbon felt cathodes were characterized, and the ROS adsorption capacity of the cathodes was analyzed via temperature programmed desorption and UV spectrophotometry. The results illustrated that the optimal molar ratio of Zn to Ni was 0.2 for cathode surface modification, and the specific surface areas of spongy and petaline ZnO0.2-NiO@rGO reached 215.26 and 230.88 mg.g(-1), respectively, which were more than 200-fold higher than that of prefabricated carbon felt. The areal capacitance values of spongy and petaline ZnO0.2-NiO@rGO cathodes reached 3033.5 and 6388.92 mC.cm(-2), respectively. The ROS concentrations on the spongy and petaline ZnO0.2-NiO@rGO cathode surfaces reached 52.36 and 64.02 mu mol.L-1, respectively, which were nearly 2-fold higher than that for prefabricated carbon felt cathode. The power densities of PAMFCs using spongy and petaline ZnO0.2-NiO@rGO as cathode electrodes were 20.18 and 31.92 mW.m(-2), respectively. The improvement of electrochemical performance of PAMFCs is partially ascribed to the enhanced ROS adsorption capacity of ZnO-NiO@rGO cathodes. Therefore, ROS adsorption capacity is recommended as an evaluation indicator for PAMFC cathodes.

MABRs with a two-step startup facilitate the formation of layered distribution of nitrifiers and denitrifiers and have higher pollutant removal rates.

The goal of this study was to investigate the effect of transmembrane gas pressure (P g) on the specific ammonium removal rate in a membrane-aerated biofilm reactor (MABR). Our experimental results show that the specific ammonium removal rate increased from 4.98 to 9.26 gN m−2 day−1 when P g increased from 2 to 20 kPa in an MABR with a biofilm thickness of approximately 600 μm. However, this improvement was not linear; there was a threshold of P g separating the stronger and weaker effects of P g. The ammonium removal rate was improved less significantly when P g was over the threshold, indicating that there is an optimal threshold of P g for maximizing ammonium removal in an MABR. The change in oxygen penetration depth (d p) is less sensitive to P g in the ammonia-oxidizing active layer than in the inactive layer in membrane-aerated biofilm. The location of the P g threshold is at the same point as the thickness of the active layer on the curve of d p versus P g; thus, the active layer thickness and the optimal P g can be determined on the basis of the changes in the slope of d p to P g.

The goal of this study was to quantify and demonstrate the dynamic effects of hydraulic retention time (HRT), organic carbon and various components of extracellular polymeric substances (EPS) produced by microorganisms on the performance of submersed hollow-fiber microfiltration (MF) membrane in a hybrid powdered activated carbon (PAC)-MF membrane bioreactor (MBR). The reactors were operated continuously for 45 days to treat surface (river) water before and after pretreatment using a biofiltration unit. The real-time levels of organic carbon and the major components of EPS including five different carbohydrates (d(+) glucose and d(+) mannose, d(+) galactose, N-acetyl-d-galactosamine and d-galactose, oligosaccharides and l(−) fucose), proteins, and polysaccharides were quantified in the influent water, foulants, and in the bulk phases of different reactors. The presence of PAC extended the filtration cycle and enhanced the organic carbon adsorption and removal more than two fold. Biological filtration improved the filtrate quality and decreased membrane fouling. However, HRT influenced the length of the filtration cycle and had less effect on organic carbon and EPS component removal and/or biodegradation. The abundance of carbohydrates in the foulants on MF surfaces was more than 40 times higher than in the bulk phase, which demonstrates that the accumulation of carbohydrates on membrane surfaces contributed to the increase in transmembrane pressure significantly and PAC was not a potential adsorbent of carbohydrates. The abundance of N-acetyl-d-galactosamine and d-galactose was the highest in the foulants on membranes receiving biofilter-treated river water. Most of the biological fouling compounds were produced inside the reactors due to biodegradation. PAC inside the reactor enhanced the biodegradation of polysaccharides up to 97% and that of proteins by more than 95%. This real-time extensive and novel study demonstrates that the PAC-MF hybrid MBR is a sustainable technology for treating river water.

Fluid Mechanics of Environmental Interfaces, Second EditionUnderstanding BiocorrosionTextbook of Diagnostic Microbiology E-BookFundamentals of Food BiotechnologyFundamentals and Applications of BioremediationBiofilm InfectionsBiofilm Control and Antimicrobial AgentsPhoton CountingHandbook of Nanoceramic and Nanocomposite Coatings and MaterialsMathematical Modeling of BiofilmsBiofilms in Wastewater TreatmentFundamentals of Biofilm Research, Second EditionRecent Trends in Image Processing and Pattern RecognitionBiofilm and Materials ScienceThe Microbiology of Nuclear Waste DisposalBiofilms and Veterinary MedicineThe New Science of MetagenomicsManual of BiocorrosionFundamentals and Applications of BioremediationFundamentals of Biofilm Research, Second EditionBioprocess EngineeringEncyclopedia of Meat SciencesBiofilms in Bioelectrochemical SystemsMicrobiologyProceedings-Second International Conference on Fixed-Film Biological ProcessesEnvironmental Biotechnology: Principles and Applications, Second EditionThe Microbiological Quality of FoodFundamentals of Biofilm ResearchCharacterization of BiomaterialsMicrobial BiofilmsAdvances in Ceramics for Environmental, Functional, Structural, and Energy Applications IIRecent Trends in Biofilm Science and TechnologyMicrobial BiofilmsFundamentals of MicrobiologyBiomaterials and Medical Device Associated InfectionsFundamentals of Microbiome ScienceAnnual Reports on NMR SpectroscopyAdvances in Ceramics for Environmental, Functional, Structural, and Energy ApplicationsHeterotrophic Plate Counts and Drinking-water SafetyThe MBR Book This book will cover both the evidence for biofilms in many chronic bacterial infections as well as the problems facing these infections such as diagnostics and treatment regimes. A still increasing interest and emphasis on the sessile bacterial lifestyle biofilms has been seen since it was realized that that less than 0.1% of the total microbial biomass lives in the planktonic mode of growth. The term was coined in 1978 by Costerton et al. who defined the term biofilm for the first time.In 1993 the American Society for Microbiology (ASM) recognised that the biofilmmode of growth was relevant to microbiology. Lately many articles have been published on the clinical implications of bacterial biofilms. Both original articles and reviews concerning the biofilm problem are available.Annual Reports on NMR Spectroscopy, Volume 97, provides an in-depth accounting of progress in nuclear magnetic resonance (NMR) spectroscopy and its many applications. In recent years, no other technique has gained as much significance. It is used in all branches of science in which precise structural determination is required, and in which the nature of interactions and reactions in solution is being studied. This book has established itself as a premier resource for both specialists and non-specialists who are looking to become familiar with new techniques and applications pertaining to NMR spectroscopy. Serves as the premier resource for learning the new techniques and applications of NMR spectroscopy Provides a key reference for chemists and physicists using NMR spectroscopy to study the structure and dynamics of molecules Covers all aspects of molecular science, including MRI (Magnetic Resonance Imaging)This book explains the formation of biofilm on materials surfaces in an industrial setting. The authors describe new developments in understanding of biofilm formation, detection, and control from the viewpoint of materials science and engineering. The book details the range of issues caused by biofilm formation and the variety of affected industries.This book serves as a manual of research techniques for electrochemically active biofilm research. Using examples from real biofilm research to illustrate the techniques used for electrochemically active biofilms, this book is of most use to researchers and educators studying microbial fuel cell and bioelectrochemical systems. The book emphasizes the theoretical principles of bioelectrochemistry, experimental procedures and tools useful in quantifying electron transfer processes in biofilms, and mathematical modeling of electron transfer in biofilms. It is divided into three sections: Biofilms: Microbiology and microbioelectrochemistry Focuses on the microbiologic aspect of electrochemically active biofilms and details the key points of biofilm preparation and electrochemical measurement Electrochemical techniques to study electron transfer processes Focuses on electrochemical characterization and data interpretation, highlighting key factors in the experimental procedures that affect reproducibility Applications Focuses on applications of electrochemically active biofilms and development of custom tools to study electrochemically active biofilms. Chapters detail how to build the reactors for applications and measure parametersPublisher's Note: Products purchased from Third Party sellers are not guaranteed by the publisher for quality, authenticity, or access to any online entitlements included with the product. The classic environmental biotechnology textbook—fully updated for the latest advances This thoroughly revised educational resource presents the biological principles that underlie modern microbiological treatment technologies. Written by two of the field’s foremost researchers, Environmental Biotechnology: Principles and Applications, Second Edition, clearly explains the new technologies that have evolved over the past 20 years, including direct anaerobic treatments, membrane-based processes, and granular processes. The first half of the book focuses on theory and tools; the second half offers practical applications that are clearly illustrated through real-world examples. Coverage includes: • Moving toward sustainability • Basics of microbiology • Biochemistry, metabolism, genetics, and information flow • Microbial ecology • Stoichiometry and energetics • Microbial kinetics and products • Biofilm kinetics • Reactor characteristics and kinetics • Methanogenesis • Aerobic suspended-growth processes • Aerobic biofilm processes • Nitrogen transformation and recovery • Phosphorus removal and recovery • Biological treatment of drinking waterBiocorrosion refers to corrosion influenced by bacteria adhering to surfaces in biofilms. Biocorrosion is a major problem in areas such as cooling systems and marine structures where biofilms can develop. This book summarises key recent research in this subject. Part one looks at theories of biocorrosion and measurement techniques. Part two discusses how bacteria and biofilms result in biocorrosion. The final part of the book includes case studies of biocorrosion in areas as diverse as buildings, fuels, marine environments and cooling systems. Provides a detailed overview of biocorrosion and the different scientific and/or industrial problems related to microbially induced corrosion Introduces a variety of investigative techniques and methodologies that are employed in diagnosing and evaluating microbially induced corrosion Includes case studies on: biodeterioration of building materials; biocorrosion issues associated with diesel and biofuels; marine biocorrosion; corrosion of open recirculating cooling water systems and cooling system components; the effect of H2S on steel corrosionThe Microbiology of Nuclear Waste Disposal is a state-of-the-art reference featuring contributions focusing on the impact of microbes on the safe long-term disposal of nuclear waste. This book is the first to cover this important emerging topic, and is written for a wide audience encompassing regulators, implementers, academics, and other stakeholders. The book is also of interest to those working on the wider exploitation of the subsurface, such as bioremediation, carbon capture and storage, geothermal energy, and water quality. Planning for suitable facilities in the U.S., Europe, and Asia has been based mainly on knowledge from the geological and physical sciences. However, recent studies have shown that microbial life can proliferate in the inhospitable environments associated with radioactive waste disposal, and can control the long-term fate of nuclear materials. This can have beneficial and damaging impacts, which need to be quantified. Encompasses expertise from both the bio and geo disciplines, aiming to foster important collaborations across this disciplinary divide Includes reviews and research papers from leading groups in the field Provides helpful guidance in light of plans progressing worldwide for geological disposal facilities Includes timely research for planning and safety case developmentBioprocess Engineering involves the design and development of equipment and processes for the manufacturing of products such as food, feed, pharmaceuticals, nutraceuticals, chemicals, and polymers and paper from biological materials. It also deals with studying various biotechnological processes. "Bioprocess Kinetics and Systems Engineering" first of its kind contains systematic and comprehensive content on bioprocess kinetics, bioprocess systems, sustainability and reaction engineering. Dr. Shijie Liu reviews the relevant fundamentals of chemical kinetics-including batch and continuous reactors, biochemistry, microbiology, molecular biology, reaction engineering, and bioprocess systems engineeringintroducing key principles that enable bioprocess engineers to engage in the analysis, optimization, design and consistent control over biological and chemical transformations. The quantitative treatment of bioprocesses is the central theme of this book, while more advanced techniques and applications are covered with some depth. Many theoretical derivations and simplifications are used to demonstrate how empirical kinetic models are applicable to complicated bioprocess systems. Contains extensive illustrative drawings which make the understanding of the subject easy Contains worked examples of the various proc

The goal of this study was to develop a power management system (PMS) that could power a submersible ultrasonic receiver (SUR) continuously to keep accurate time and listen to ultrasonic signals when there was enough energy for a complete scan. We developed a PMS and modified the hardware and firmware of the SUR to allow it to be controlled by our PMS. Thus, the SUR became optimized for the SMFC and was controlled by the PMS. The SUR switched to idle mode without stopping the RTC when there was not enough energy for a complete scan. The PMS used a 350-F capacitor to store microbial energy. The SMFC was deployed in the Palouse River, Pullman, WA. The integrated PMS was tested and operated the SUR continuously for six weeks. Our integrated PMS and sensor could make SMFCs a more viable renewable power source for continuous environmental monitoring. We found that the SUR could only be powered continuously if its operation was controlled by the PMS. We believe that future applications of more complex sensors could benefit from our novel approach of controlling the sensor using the PMS for uninterrupted operation even when the data are collected intermittently.

This review examines the electrochemical techniques used to study extracellular electron transfer in the electrochemically active biofilms that are used in microbial fuel cells and other bioelectrochemical systems. Electrochemically active biofilms are defined as biofilms that exchange electrons with conductive surfaces: electrodes. Following the electrochemical conventions, and recognizing that electrodes can be considered reactants in these bioelectrochemical processes, biofilms that deliver electrons to the biofilm electrode are called anodic, ie electrode-reducing, biofilms, while biofilms that accept electrons from the biofilm electrode are called cathodic, ie electrode-oxidizing, biofilms. How to grow these electrochemically active biofilms in bioelectrochemical systems is discussed and also the critical choices made in the experimental setup that affect the experimental results. The reactor configurations used in bioelectrochemical systems research are also described and the authors demonstrate how to use selected voltammetric techniques to study extracellular electron transfer in bioelectrochemical systems. Finally, some critical concerns with the proposed electron transfer mechanisms in bioelectrochemical systems are addressed together with the prospects of bioelectrochemical systems as energy-converting and energy-harvesting devices.

To quantify the effect of dynamic particle size changes and degradation and accumulation of suspended solids (SS) in influents to reactors on membrane fouling frequency in hybrid powder-activated carbon (PAC)–microfiltration (MF) reactors, we operated a PAC–MF system (hollow-fiber module) for more than five months to purify river water before and after pretreatment by a biofilter. The transmembrane pressure, backwashing pressure, resistance to filtration, and SS accumulation and degradation during these dynamic changes were evaluated. The initial dose of PAC was 40g/L of the reactor and no additional PAC was added during this continuous operational period. The presence of PAC reduced the membrane resistance to filtration even at the end of filtration period when the number of particles in the smallest range (>1.0–3.6μm) was the highest measured by the flow cytometer and microscopy image analysis. This resistance was reduced further when the river water was biofiltered prior to membrane filtration. This real-time study demonstrates that over time PAC and other particles coming into the reactors through the influents degrade and/or become smaller because of the turbulence caused by continuous aeration below the MF membrane fibers. The number of particles in the reactors with diameters less than 10μm increased with time, increasing the fouling frequency; however, the presence of PAC further reduced the particle enhanced fouling. The presence of PAC also increased SS degradation by up to 10%. The increased number of bacteria inside the PAC–MF systems did not contribute to the number of membrane fouling. Even though the particle sizes inside the reactors became smaller with time, the gradual increase in net accumulation of SS was also an important factor controlling the performance of the PAC–MF system.

This paper presents a power management system for energy harvesting with multiple microbial fuel cells (MFCs), devices that can generate electricity in water environments using electro-chemical reactions caused by bacteria. The system first connects a capacitor to each MFC in parallel so that the capacitors are charged by the MFCs. Then the system disconnects the capacitors from the MFCs, connects all the capacitors in series, and connects all the series-connected capacitors to a boost converter. As a result, the boost converter receives sufficient voltage and energy from the capacitors and starts up, providing high enough voltage and current to the load. The system allows low voltage low current MFCs to be used to power high voltage high current electronic devices deployed in the water. The system was tested in the lab.

The structure of biofilms can be numerically quantified from microscopy images using structural parameters. These parameters are used in biofilm image analysis to compare biofilms, to monitor temporal variation in biofilm structure, to quantify the effects of antibiotics on biofilm structure and to determine the effects of environmental conditions on biofilm structure. It is often hypothesized that biofilms with similar structural parameter values will have similar structures; however, this hypothesis has never been tested. The main goal was to test the hypothesis that the commonly used structural parameters can characterize the differences or similarities between biofilm structures. To achieve this goal (1) biofilm image reconstruction was developed as a new tool for assessing structural parameters, (2) independent reconstructions using the same starting structural parameters were tested to see how they differed from each other, (3) the effect of the original image parameter values on reconstruction success was evaluated, and (4) the effect of the number and type of the parameters on reconstruction success was evaluated. It was found that two biofilms characterized by identical commonly used structural parameter values may look different, that the number and size of clusters in the original biofilm image affect image reconstruction success and that, in general, a small set of arbitrarily selected parameters may not reveal relevant differences between biofilm structures. Biotechnol. Bioeng. 2011; 108:1383–1394. © 2011 Wiley Periodicals, Inc.

This paper presents a system that can harvest energy in the water and use the harvested energy to power electronic devices deployed in the water. The system consists of a microbial fuel cell (MFC) and a power management system. The MFC uses electrochemical reactions and bacteria that are safe and abundant in the water to harvest energy and generate electricity. The power management system, consisting of a charge pump, a super capacitor, and a boost converter, accumulates and stores the energy harvested by the MFC in the super capacitor and bursts power to the load. The power management system also boosts the voltage of the MFC to a sufficient level for the electronic devices. The presented energy harvest system is sustainable, environmentally friendly and maintenance free. The system has been tested and proven through experimental work.

Effect of Location on the Performance of Benthic Microbial Fuel CellsThe lifetime of remote sensors is often limited by battery power. Replacing batteries is costly and time-consuming, and it may be impractical when the sensors are deployed at remote locations. Benthic microbial fuel cells (BMFCs) constitute a promising alternative power source that may replace or supplement batteries. In this study we investigated power generation by BMFCs deployed in coastal...Author(s)Alim DewanTimothy EwingMark E. NielsenClare E. ReimersBart ChadwickKen RichterZbigniew LewandowskiHaluk BeyenalSourceProceedings of the Water Environment FederationSubjectSession 1: Microbial Fuel CellsDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2010ISSN1938-6478SICI1938-6478(20100101)2010:7L.48;1-DOI10.2175/193864710798208520Volume / Issue2010 / 7Content sourceResiduals and Biosolids ConferenceFirst / last page(s)48 - 51Copyright2010Word count182Subject keywordsMicrobial fuel cellremote sensorsrenewable power generation

This chapter, as the title indicates, is about imaging and quantifying biofilm structure. The term biofilm structure was conceived in reference to the distribution of biomass in the space occupied by a biofilm, after it became obvious that this distribution was nonuniform. This is the original definition of biofilm structure and we have adhered to this definition in most parts of this text. However, we cannot ignore the fact that the definition of biofilm structure has expanded. Since the time when the original meaning of the term was proposed, nonuniform distribution of other components of biofilm has been demonstrated, in particular the nonuniform distribution of various physiological groups of microorganisms and the nonuniform distribution of various polymeric substances, collectively called extracellular polymeric substances (EPS). The distribution of physiological groups in biofilms has become a well-studied branch of biofilm research - known as microbial community structure analysis, and quantification of the distribution of various polymers constituting EPS has made progress as well. The tools used to quantify the nonuniform distribution of various components in biofilms have much in common. The smallest dimension of the biofilm, the thickness, is conveniently expressed in microns, and it determines that the resolution of tools used to study the distribution of the components in biofilms must provide spatial resolution better than the thickness of the biofilm. This clearly includes several types of microscopy. In this chapter, we discuss these tools and where appropriate we illustrate their use with examples. Finally, the distribution of the components in biofilms needs to be quantified, and we describe software packages that can be used for this purpose. The concept of biofilm structure is dynamic and flexible, and able to accommodate the distributions of the components that have been described as well as the distribution of components that will be described in the future.

A combination of microfiltration (MF) membrane with a high concentration (40g/L of the reactor) of powdered activated carbon (PAC) efficiently and continuously removed trihalomethanes (THMs) and total organic carbon (TOC) from river water for a period of two months. Without PAC, the membrane reactor was able to remove less than 18% of THMs and less than 5% of TOC; with PAC, 65 to 95% of THMs and TOC were removed. Even though the THMs concentration in the influent was steadily increasing (reaching 50μg/L), THMs concentration in the effluents from the reactors with PAC were consistently below 15μg/L. While the MF membranes alone could not remove organics, PAC and microbial activity in the biofilm deposited on the PAC particles assured long term and continuous removal of THMs. No additional PAC was added into or removed from the reactors during the filtration period. Operational parameters such as the backwashing of the membrane, interval of the filtration cycle and biological pretreatment of the river water had a small effect on the extent of THMs removal, but they increased the filtration time prior to membrane cleaning and improved the overall performance of the reactors.

The chapter demonstrates that biofilms can influence the corrosion of metals (1) by consuming oxygen, the cathodic reactant; (2) by increasing the mass transport of the corrosion reactants and products, therefore changing the kinetics of the corrosion process; (3) by generating corrosive substances; and (4) by generating substances that serve as auxiliary cathodic reactants. These interactions do not exhaust the possible mechanisms by which biofilm microorganisms may affect the corrosion of metals; rather, they represent those few instances in which we understand the microbial reactions and their effect on the electrochemical reactions characteristic of corrosion. In addition, we can use electrochemical and chemical measurements to detect one or more products of these reactions. An important aspect of quantifying mechanisms of microbially influenced corrosion is to demonstrate how the microbial reactions interfere with the corrosion processes and, based on this, identify products of these reactions on the surfaces of corroding metals using appropriate analytical techniques. The existence of these products, associated with the increasing corrosion rate, is used as evidence that the specific mechanism of microbially influenced corrosion is active. There is no universal mechanism of MIC. Instead, many mechanisms exist and some of them have been described and quantified better than other. Therefore, it does not seem reasonable to search for universal mechanisms, but it does seem reasonable to search for evidence of specific, well-defined microbial involvement in corrosion of metals.

In this study, we compare the efficiencies of harvesting energy from microbial fuel cells (MFC) using two modes of operation: (1) continuous-passing the current through an electrical load-and (2) intermittent-first accumulating the energy in a capacitor and then discharging it through the load. Each of these two modes of operation has advantages and disadvantages: the first mode of operation allows the continuous powering of low-power-consuming devices, and the second mode of operation allows the intermittent powering of high-power-consuming devices. We used a two-compartment MFC: in the anodic compartment, Shewanella oneidensis MR-1 was grown using lactate as an electron donor, whereas in the cathodic compartment we used an electrode made of manganese-based catalyzed carbon bonded to a current-collecting screen made of platinum mesh and oxygen as the electron acceptor. The maximum power generated by harvesting energy intermittently was 152 microW, which is 111% higher than the 72 microW generated by harvesting the energy continuously. We conclude that in the operation of MFCs it is beneficial to harvest the energy intermittently. This not only allows the powering of external devices of high power consumption but also allows generating power with greater energy efficiency than does harvesting the energy continuously.