Download or read book Volatile Fatty Acid Effects on Nitrite Removal and Nitrate Formation During Activated Sludge Treatment written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reaction sequences of nitrifying and denitrifying bacteria are widely used to eliminate nitrogenous compounds from wastewater. During nutrification, ammonia is oxidized to nitrite by autotrophic ammonia oxidizing bacteria and nitrite is further oxidized to nitrate by nitrite oxidizers. Subsequently, nitrate or nitrite is reduced by denitrifying bacteria to gaseous nitrogen compounds. It is common knowledge that nitrification is an aerobic process and denitrification an anaerobic process. However, recent research has shown that denitrification can occur under aerobic conditions in pure cultures. Volatile fatty acids (VFAs), produced during anaerobic treatment processes, can affect both nitrite oxidation and aerobic denitrification. VFAs were shown to reduce nitrate formation via nitrite oxidation in activated sludge systems and to simulate aerobic denitrification in pure cultures. Nitrite removal inhibition by VFAs observed in activated sludge systems may be due to the level of aerobic denitrification which occurs. Investigation of this possibility can provide a new insight for the removal of nitrogen from wastewater and possibly reduce the chemical and energy demand for nitrogen treatment. The overall goal of this research was to demonstrate that nitrification and denitrification could occur in the same reactor under aerobic conditions in the presence of VFAs. The impact of VFAs on nitrite removal and nitrate formation in activated sludge systems was studied in batch and CSTR experiments. The experimental work included measurements of nitrite removal, nitrate formation and CO2 fixation in the absence and presence of VFAs. In addition, molecular tools were applied to examine changes in microbial population density when the population was exposed to VFAs. Production of N2O and activity of periplasmic nitrate reductase enzyme (NAP) which catalyses the first step of aerobic denitrification were also analyzed. Nitrite removal and nitrate formation rates were reduced in the presence of VFA's in batch experiments. Nitrate formation rate was reduced to a greater extent (74%) than nitrite removal rate (35%) indicating that products other than nitrate were formed during nitrite oxidation. The addition of VFAs into an activated sludge CSTR treating municipal wastewater resulted in a rapid decrease in nitrate formation rate (> 70% reduction); however, nitrite removal was not reduced. No nitrogen was discharged in the effluent of the CSTR indicating that nitrogenous compounds were completely removed from the wastewater. In contrast, VFAs were not found to impact carbon dioxide fixation efficiency in either batch or CSTR experiments although it is generally believed to be limited by the availability of energy derived from nitrite oxidation.
Download or read book Acclimation of Nitrifiers for Activated Sludge Treatment written by Robert A. Zimmerman and published by IWA Publishing. This book was released on 2004-06-30 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrification kinetics were evaluated in bench-scale batch reactors fed with a synthetic wastewater containing approximately 1,000 mg ammonia-nitrogen (NH3-N)/L operated at 5, 10, and 20 day solids retention times (SRTs) and with dewatered biosolids supernatant (1,126 to 1,680 mg NH3-N/L) operated at a 20-day SRT. For the 5- and 10-day SRTs, complete nitrification appeared to be inhibited by the presence of un-ionized ammonia and un-ionized nitrous acid. For the 20-day SRT, near complete nitrification was observed for both substrates. Observed ammonium oxidation rates decreased with increasing SRT. Observed yield coefficients were similar for all SRTs and substrates. Fully established steady-state conditions were observed at higher SRTs despite process start-up and operational considerations. Although it may be possible to culture a nitrifier population capable of near-complete nitrification at lower SRTs, the design configuration and operational strategy must mitigate the potential for un-ionized ammonia and un-ionized nitrous acid inhibition (e.g. process start-up at lower concentration with gradual increase to higher concentration, continuous feed operation, etc). Batch bioaugmentation analyses were conducted in the mixed liquor suspended solids and final clarifier effluent from a non-nitrifying activated sludge with seed nitrifiers developed from the 20-day SRT reactors and with biomass from a nitrifying trickling filter facility. Ammonia removal was observed in all bioaugmentation analyses with no apparent lag or acclimation period. Observed ammonium oxidation rates were not significantly different between the seed and batch bioaugmentation reactors. Acclimation does not appear to be a critical obstacle for nitrifier bioaugmentation when environmental conditions (e.g. temperature, pH, etc.) between the seed and bioaugmentation processes are not significantly different.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aerobic Granular Sludge written by S. Bathe and published by IWA Publishing. This book was released on 2005-03-31 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerobic Granular Sludge has recently received growing attention by researchers and technology developers, worldwide. Laboratory studies and preliminary field tests led to the conclusion that granular activated sludge can be readily established and profitably used in activated sludge plants, provided 'correct' process conditions are chosen. But what makes process conditions 'correct'? And what makes granules different from activated sludge flocs? Answers to these question are offered in Aerobic Granular Sludge. Major topics covered in this book include: Reasons and mechanism of aerobic granule formation Structure of the microbial population of aerobic granules Role, composition and physical properties of EPS Diffuse limitation and microbial activity within granules Physio-chemical characteristics Operation and application of granule reactors Scale-up aspects of granular sludge reactors, and case studies Aerobic Granular Sludge provides up-to-date information about a rapidly emerging new technology of biological treatment.
Download or read book Understanding of Nitrifying and Denitrifying Bacterial Population Dynamics in an Activated Sludge Process written by Tongzhou Wang and published by . This book was released on 2014 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen removal from wastewater has been an important objective in treatment since the 1960s and is one of the most important biological processes used. The progression of knowledge has evolved in stages moving from simple stoichiometric equations into the modern activated sludge models of today. These models use surrogates such as volatile solids for biomass and outcome parameters such as nitrate and nitrite in the secondary effluent to simulate biological activity. Thus, even the most complex models fail to capture the cyclical nature of bacterial abundance and the operating parameters which drive these cycles in full-scale plants. Better understanding of microbial communities has been attempted through the application of florescent in situ hybridization (FISH), which has determined the presence of specific organisms and the distributions of nitrifying and denitrifying populations within a single grab sample. New techniques such as quantitative polymerase chain reaction (qPCR) allowed the identification and quantification of nitrifying and denitrifying bacterial populations over time in full- scale plants. This has permitted the determination of relationships between organisms and operating parameters, which is missing from the majority of earlier microbial studies of wastewater treatment processes.Intense monitoring of bacterial populations involved in nitrification and denitrification was used in this dissertation to identify and illustrate how application of these molecular tools can be used improve plant performance. The overall findings of this study showed that plant performance should be optimized seasonally for maximum nitrification and to maximize denitrification anoxic dissolved oxygen needs to be carefully monitored during the winter and spring to prevent excess oxygen from inhibiting denitrification activity. Furthermore, this study suggests that consortia of bacterial groups carried out denitrification and no one single group could be identified which represented more than 50% of the population. This latter finding suggests that interactions, of what might otherwise be considered as minor groups, become important in understanding overall influences on the denitrification process. This was shown by the inhibition of the abundance of denitrifying bacteria through the production of nitrite by a bulking organism (Thiothrix Eikelboomii ).In the first study, we determined the nitrifying populations (ammonia oxidizing bacteria, Nitrobacter spp. and Nitrospira spp.) and the total bacterial population were most affected by five of the major physicochemical parameters. Water temperature, nitrite produced, nitrate produced, solids retention time, and pH were found to be the major physicochemical parameters controlling these bacterial dynamics. Two clusters in Principal Component 1(PC1) reflected a seasonality shift at 26.9°C. Temperature was found to be the parameter most directly affecting all bacterial populations in the warmer seasons (July-December), while nitrite produced and pH showed direct negative impacts on the bacterial populations in the cooler seasons (January-June) in the principal component analysis plot. PC1 and PC2 together accounted for 59.8% of the total variance, and the first six Principal Components accounted for 90.2% of total variance. Nitrifying and total bacterial abundance were strictly dependent on temperature in the summer time and inhibited by pH and nitrite in the winter season. This study found SRT needs to be extended by approximately 3.6 days to achieve optimum nitrification and the reduction of the ammonia-oxidizing bacteria: nitrite-oxidizing bacteria ratio of 9.5:1 to 2:1, because the SRT is too short for the Nitrobacter spp. and Nitrospira spp. growth rates.In the second study, two major denitrifying microbial groups, Thauera-like bacteria and Zoogloea-Methyloversatilis-like bacteria, which accounted for 34% on average of the total bacterial community measured using quantitative PCR (qPCR), were investigated in relation to the denitrification ability in a full scale plant. In this study of 11-months in warm wastewater (23-28.6 °C), dissolved oxygen (DO) in the anoxic zone was the most important parameter that determined denitrification efficiency when the temperature was below 27°C. Zoogloea-Methyloversatilis -like bacteria correlated significantly with denitrification ( r= 0.52, p
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1991 with total page 1210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biological Phosphorus Removal written by P. M. J. Janssen and published by IWA Publishing. This book was released on 2002-05-31 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological phosphorus (bio-P) removal has become a reliable and well-understood process within wastewater treatment, despite being one of the most complex processes in the activated sludge process. Extended fundamental and full-scale research has been carried out into the bio-P process and the state-of-the-art is described in this report. A summarising historical overview gives insight into the establishment of the appropriate microbiological and biochemical basis of the process and the development of bio-P configurations in practice. Aspects of the bio-P process that have a direct influence on the efficiency of phosphorus removal are subjected to an in-depth investigation. This report presents guidelines for design and dimensioning in order to introduce and/or optimise the bio-P process in practice. Twelve bio-P installations are extensively described and the operational results and experiences are related to existing bio-P knowledge and guidelines. Based on a number of parameters, a comparison is made between the described bio-P plants. A steady state model is verified with extensive periods of practical experience of the plants. The bio-P model, which is provided on CD-ROM (available for download here), offers a reliable insight into the bio-P process, coupled with sensitivity analyses regarding wastewater characteristics and process parameters for the anaerobic volume and the P-ortho concentration in the final effluent. The report ends with a systematic approach to the design of the bio-P process, based on the background of the bio-P process itself, much practical experience and the analysis of operational bio-P plants. Also presented is a systematic approach to tackle operational aspects of the bio-P process in order to generate an acceptable low P effluent concentration. This optimisation of the bio-P process operation is supported by a decision diagram. Biological Phosphorus Removal will be an invaluable source of information for all those concerned with wastewater treatment, including plant managers, process designers, consultants and researchers.
Download or read book Anaerobic Fermentations written by Illinois State Water Survey and published by . This book was released on 1939 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Denitrification Using Volatile Fatty Acids VFAs written by Dayong Li (M.E.) and published by . This book was released on 2001 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Prokaryotes written by Edward F. DeLong and published by Springer. This book was released on 2013-03-22 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Prokaryotes is a comprehensive, multi-authored, peer reviewed reference work on Bacteria and Achaea. This fourth edition of The Prokaryotes is organized to cover all taxonomic diversity, using the family level to delineate chapters. Different from other resources, this new Springer product includes not only taxonomy, but also prokaryotic biology and technology of taxa in a broad context. Technological aspects highlight the usefulness of prokaryotes in processes and products, including biocontrol agents and as genetics tools. The content of the expanded fourth edition is divided into two parts: Part 1 contains review chapters dealing with the most important general concepts in molecular, applied and general prokaryote biology; Part 2 describes the known properties of specific taxonomic groups. Two completely new sections have been added to Part 1: bacterial communities and human bacteriology. The bacterial communities section reflects the growing realization that studies on pure cultures of bacteria have led to an incomplete picture of the microbial world for two fundamental reasons: the vast majority of bacteria in soil, water and associated with biological tissues are currently not culturable, and that an understanding of microbial ecology requires knowledge on how different bacterial species interact with each other in their natural environment. The new section on human microbiology deals with bacteria associated with healthy humans and bacterial pathogenesis. Each of the major human diseases caused by bacteria is reviewed, from identifying the pathogens by classical clinical and non-culturing techniques to the biochemical mechanisms of the disease process. The 4th edition of The Prokaryotes is the most complete resource on the biology of prokaryotes. The following volumes are published consecutively within the 4th Edition: Prokaryotic Biology and Symbiotic Associations Prokaryotic Communities and Ecophysiology Prokaryotic Physiology and Biochemistry Applied Bacteriology and Biotechnology Human Microbiology Actinobacteria Firmicutes Alphaproteobacteria and Betaproteobacteria Gammaproteobacteria Deltaproteobacteria and Epsilonproteobacteria Other Major Lineages of Bacteria and the Archaea
Download or read book Sludge Reduction Technologies in Wastewater Treatment Plants written by Paola Foladori and published by IWA Publishing. This book was released on 2010-07-31 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sludge Reduction Technologies in Wastewater Treatment Plants is a review of the sludge reduction techniques integrated in wastewater treatment plants with detailed chapters on the most promising and most widespread techniques. The aim of the book is to update the international community on the current status of knowledge and techniques in the field of sludge reduction. It will provide a comprehensive understanding of the following issues in sludge reduction: principles of sludge reduction techniques; process configurations; potential performance; advantages and drawbacks; economics and energy consumption. This book will be essential reading for managers and technical staff of wastewater treatment plants as well as graduate students and post-graduate specialists.
Download or read book Industrial Biorefineries and White Biotechnology written by Ashok Pandey and published by Elsevier. This book was released on 2015-05-08 with total page 731 pages. Available in PDF, EPUB and Kindle. Book excerpt: Industrial Biorefineries and White Biotechnology provides a comprehensive look at the increasing focus on developing the processes and technologies needed for the conversion of biomass to liquid and gaseous fuels and chemicals, in particular, the development of low-cost technologies. During the last 3-4 years, there have been scientific and technological developments in the area; this book represents the most updated information and technological perspective on the topic. Provides information on the most advanced and innovative pretreatment processes and technologies for biomass Covers information on lignocellulosic and algal biomass to work on the principles of biorefinery Provides information on integration of processes for the pretreatment of biomass Designed as a textbook for both graduate students and researchers
Download or read book Mathematical Modelling and Computer Simulation of Activated Sludge Systems written by Jacek Makinia and published by IWA Publishing. This book was released on 2020-03-02 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and the latest developments in modelling the innovative nitrogen removal processes. Furthermore, a new section on micropollutant removal has been added. The focus of modelling has been shifting in the last years to models that can describe the performance of a whole plant (plant-wide modelling). The expanded part of this new edition introduces models describing the most important processes interrelated with the mainstream activated sludge systems as well as models describing the energy balance, operating costs and environmental impact. The complex process evaluation, including minimization of energy consumption and carbon footprint, is in line with the present and future wastewater treatment goals. By combining a general introduction and a textbook, this book serves both intermediate and more experienced model users, both researchers and practitioners, as a comprehensive guide to modelling and simulation studies. The book can be used as a supplemental material at graduate and post-graduate levels of wastewater engineering/modelling courses.
Download or read book Handbook of Water and Wastewater Microbiology written by Duncan Mara and published by Elsevier. This book was released on 2003-08-07 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Access to safe water is a fundamental human need and therefore a basic human right" --Kofi Annan, United Nations Secretary General Edited by two world-renowned scientists in the field, The Handbook of Water and Wastewater Microbiology provides a definitive and comprehensive coverage of water and wastewater microbiology. With contributions from experts from around the world, this book gives a global perspective on the important issues faced in the provision of safe drinking water, the problems of dealing with aquatic pollution and the processes involved in wastewater management. Starting with an introductory chapter of basic microbiological principles, The Handbook of Water and Wastewater Microbiology develops these principles further, ensuring that this is the essential text for process engineers with little microbiological experience and specialist microbiologists alike. Comprehensive selection of reviews dealing with drinking water and aquatic pollution Provides an understading of basic microbiology and how it is applied to engineering process solutions Suitable for all levels of knowledge in microbiology -from those with no background to specialists who require the depth of information
Download or read book Metalloenzymes in Denitrification written by Isabel Moura and published by Royal Society of Chemistry. This book was released on 2016-11-15 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reduction of nitrate to nitrogen by metalloenzymes is a vital step in the nitrogen cycle. The importance of this pathway has inspired efforts to understand in greater depth the mechanisms involved. This book presents and discusses the latest information on multiple aspects of denitrification. Written by recognized specialists in the field, this book describes the bioinorganic aspects and the key enzymes involved in denitrification, including their structure, function and mechanisms. Active site modelling, novel methodologies for monitoring denitrification in vivo and biotechnological methods for water treatment are discussed. The book also focusses on the environmental implications of denitrification, such nitrate accumulation and the release of nitrous oxide into the atmosphere from excessive fertiliser use. An important topic in many biological, environmental and agricultural contexts, this book will aid teaching and help bioinorganic chemists and biotechnologists gain an up-to-date picture of the science behind the denitrification process.
Download or read book Waste Biorefinery written by Thallada Bhaskar and published by Elsevier. This book was released on 2018-04-13 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: Waste Biorefinery: Potential and Perspectives offers data-based information on the most cutting-edge processes for the utilisation of biogenic waste to produce biofuels, energy products, and biochemicals – a critical aspect of biorefinery. The book explores recent developments in biochemical and thermo-chemical methods of conversion and the potential generated by different kinds of biomass in more decentralized biorefineries. Additionally, the book discusses the move from 200 years of raw fossil materials to renewable resources and how this shift is accompanied by fundamental changes in industrial manufacturing technologies (from chemistry to biochemistry) and in logistics and manufacturing concepts (from petrochemical refineries to biorefineries). Waste Biorefinery: Potential and Perspectives designs concepts that enable modern biorefineries to utilize all types of biogenic wastes, and to integrate processes that convert byproduct streams to high-value products, achieving higher cost benefits. This book is an essential resource for researchers and students studying biomass, biorefineries, and biofuels/products/processes, as well as chemists, biochemical/chemical engineers, microbiologists, and biotechnologists working in industries and government agencies. Details the most advanced and innovative methods for biomass conversion Covers biochemical and thermo-chemical processes as well as product development Discusses the integration of technologies to produce bio-fuels, energy products, and biochemicals Illustrates specific applications in numerous case studies for reference and teaching purposes
Download or read book Anaerobic Digestion Model No 1 ADM1 written by IWA Task Group for Mathematical Modelling of Anaerobic Digestion Processes and published by IWA Publishing. This book was released on 2002-02-01 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: The IWA Task Group for Mathematical Modelling of Anaerobic Digestion Processes was created with the aim to produce a generic model and common platform for dynamic simulations of a variety of anaerobic processes. This book presents the outcome of this undertaking and is the result of four years collaborative work by a number of international experts from various fields of anaerobic process technology. The purpose of this approach is to provide a unified basis for anaerobic digestion modelling. It is hoped this will promote increased application of modelling and simulation as a tool for research, design, operation and optimisation of anaerobic processes worldwide. This model was developed on the basis of the extensive but often disparate work in modelling and simulation of anaerobic digestion systems over the last twenty years. In developing ADM1, the Task Group have tried to establish common nomenclature, units and model structure, consistent with existing anaerobic modelling literature and the popular activated sludge models (See Activated Sludge Models ASM1, ASM2, ASM2d and ASM3, IWA Publishing, 2000, ISBN: 1900222248). As such, it is intended to promote widespread application of simulation from domestic (wastewater and sludge) treatment systems to specialised industrial applications. Outputs from the model include common process variables such gas flow and composition, pH, separate organic acids, and ammonium. The structure has been devised to encourage specific extensions or modifications where required, but still maintain a common platform. During development the model has been successfully tested on a range of systems from full-scale waste sludge digestion to laboratory-scale thermophilic high-rate UASB reactors. The model structure is presented in a readily applicable matrix format for implementation in many available differential equation solvers. It is expected that the model will be available as part of commercial wastewater simulation packages. ADM1 will be a valuable information source for practising engineers working in water treatment (both domestic and industrial) as well as academic researchers and students in Environmental Engineering and Science, Civil and Sanitary Engineering, Biotechnology, and Chemical and Process Engineering departments. Contents Introduction Nomenclature, State Variables and Expressions Biochemical Processes Physicochemical Processes Model Implementation in a Single Stage CSTR Suggested Biochemical Parameter Values, Sensitivity and Estimation Conclusions References Appendix A: Review of Parameters Appendix B: Supplementary Matrix Information Appendix C: Integration with the ASM Appendix D: Estimating Stoichiometric Coefficients for Fermentation Scientific & Technical Report No.13
