Design And Retrofit Of Wastewater Treatment Plants For Biological Nutritient Removal

This book presents information that can be used for the design and operation of wastewater treatment plants that utilize biological nutrient removal processes, i.e., processes that utilize biological mechanisms instead of chemical mechanisms, to remove phosphorus and nitrogen from wastewaters. The book provides: basic fundamentals, concepts, and theories; design of prefermentation units, various types of BNR systems, and secondary clarifiers; retrofitting conventional activated sludge plants; modeling considerations; and special considerations for BNR systems. It includes full-scale and pilot plant case histories, design examples, and retrofit of existing plants.

Written by noted experts in the field sharing extensive academic and industrial experience, this thoroughly updated Second Edition covers commonly used and new suspended and attached growth reactors. The authors discuss combined carbon and ammonia oxidation, activated sludge, biological nutrient removal, aerobic digestion, anaerobic processes, lagoons, trickling filters, rotating biological contactors, fluidized beds, and biologically aerated filters. They integrate the principles of biochemical processes with applications in the real world-communicating approaches to the conception, design, operation, and optimization of biochemical unit operations in a comprehensive yet lucid manner.

Simultaneous biological nutrient removal (SBNR) is the removal of nitrogen and/or phosphorus in excess of that required for biomass synthesis in biological wastewater treatment systems where there are no defined anaerobic and/or anoxic zones. The hypothesis is that one or more of three mechanisms is responsible within individual systems: variations in the bioreactor macroenvironment created by the mixing pattern, gradients within the floc microenvironment, and/or novel microorganism activity. Understanding of the mechanisms of SBNR can be expected to lead to improved efficiency and reliability in its application. Preliminary work documented SBNR in 7 full-scale OrbalTM closed loop bioreactors. A batch assay demonstrated that novel microorganism activity was of little importance in SBNR at the three plants tested. While the floc microenvironment likely plays an important role in nitrogen removal in such plants, it cannot explain phosphorus removal. A computational fluid dynamics (CFD) model was developed to elucidate the role of the bioreactor macroenvironment in SBNR. This is the first reported application of CFD to activated sludge biological wastewater treatment. Although the software and computational requirements limited model complexity, it still simulated the creation of dissolved oxygen gradients within the system, demonstrating that the anaerobic zones required for SBNR could occur.

FROM THE PREFACE In this time of dwindling budgets, increasing service needs, and increasing regulatory requirements, wastewater treatment professionals are continually called upon to upgrade their wastewater treatment plants. To do so efficiently and effectively, one must develop a clear approach to use in upgrading a plant and have the proper tools available to implement that approach. This book is meant to assist readers in developing and implementing their upgrading projects. First, Chapter 1 details the upgrading approach. The tools to be used are presented in Chapters 2 through 6. Finally, in Chapter 7, six case histories are presented to illustrate the plant upgrading techniques presented in the previous chapters. Through this book, the authors hope to assist readers in meeting their upgrade requirements, while making the most efficient use of the resources at hand.

Instrumentation, Control and Automation of Water and Wastewater Treatment and Transport Systems 1993 comprises a selection of manuscripts on the development of control strategies and their applications and on the status and future directions of Instrumentation, Control, and Automation (ICA) in the water and wastewater industry. The book starts by providing an overview of the status, the constraints and the future prospects for ICA in water and wastewater treatment and transport based on the survey responses of experts from 16 different countries. The text continues by presenting the need for dynamic modeling and simulation software to assist operations staff in developing effective instrumentation control strategies and to provide a training environment for the evaluation of such strategies. The book also covers the critical variables in system success; the use of an enterprise-wide computing that emphasizes the importance of strategic planning, performance measures, and human factors associated with the suggested implementation of applied technology; and the use of part-time unmanned operation at a large wastewater treatment plant. A functional approach based on the utility’s water and wastewater functional requirements; the collection system monitoring and control; water distribution and control systems; dynamic modeling and simulation; and process control strategy and development are also considered. This book will be beneficial to biochemists, wastewater technologists, and public health authorities.

This investigation addressed the technical and economic feasibility ofretrofitting existing Canadian municipal wasterwater treatment plants forenhanced biological phosphorus removal (EBPR). Various EBPR processes werereviewed briefly and the practicality of using these technologies compared toconventional chemical precipitation technology for removing phosphorus frommunicipal wastewaters was assessed. An attempt was made to identify thetype and size of existing treatment plants in Canada that would be mostamenable to retrofit for enhanced biological phosphorus removal. Costs werecompared for a number of EBPR alternatives and chemical precipitation. Thisstudy was not limited to a single specific plant, but was conducted inbroader context so that those conditions under which either chemical orenhanced biological phosphorus removal was more cost-effective could beidentified.

Step-by-step procedures for planning, design, construction and operation: * Health and environment * Process improvements * Stormwater and combined sewer control and treatment * Effluent disposal and reuse * Biosolids disposal and reuse * On-site treatment and disposal of small flows * Wastewater treatment plants should be designed so that the effluent standards and reuse objectives, and biosolids regulations can be met with reasonable ease and cost. The design should incorporate flexibility for dealing with seasonal changes, as well as long-term changes in wastewater quality and future regulations. Good planning and design, therefore, must be based on five major steps: characterization of the raw wastewater quality and effluent, pre-design studies to develop alternative processes and selection of final process train, detailed design of the selected alternative, contraction, and operation and maintenance of the completed facility. Engineers, scientists, and financial analysts must utilize principles from a wide range of disciplines: engineering, chemistry, microbiology, geology, architecture, and economics to carry out the responsibilities of designing a wastewater treatment plant. The objective of this book is to present the technical and nontechnical issues that are most commonly addressed in the planning and design reports for wastewater treatment facilities prepared by practicing engineers. Topics discussed include facility planning, process description, process selection logic, mass balance calculations, design calculations, and concepts for equipment sizing. Theory, design, operation and maintenance, trouble shooting, equipment selection and specifications are integrated for each treatment process. Thus delineation of such information for use by students and practicing engineers is the main purpose of this book.