The sequencing batch reactor (SBR) is perhaps the most promising and viable of the proposed activated sludge modifications today for the removal of organic carbon and nutrients. In a relatively short period, it has become increasingly popular for the treatment of domestic and industrial wastewaters, as an effective biological treatment system due to its simplicity and flexibility of operation. Mechanism and Design of Sequencing Batch Reactors for Nutrient Removal has been prepared with the main objective to provide a unified design approach for SBR systems, primarily based on relevant process stoichiometry. Specific emphasis has been placed upon the fact that such a unified design approach is also by nature the determining factor for the selection of the most appropriate cyclic operation scheme, the sequence of necessary phases and filling patterns for the particular application. The proposed basis for design is developed and presented in a stepwise approach to cover both organic carbon and nutrient removal, domestic and industrial wastewaters, strong and specific wastes. The merits of model simulation as an integral complement of process design, along with performance evaluation of SBR models are also emphasized. Scientific and Technical Report No. 19

ABSTRACT In the last decades, the awareness of environmental issues has increased in society considerably. There is an increasing need to improve the effluent quality of domestic wastewater treatment processes. This thesis describes the application of the Sequencing Batch Reactor (SBR) technology for Biological Nutrient Removal (BNR) from the wastewater. In particular, the work presented evolves from the nitrogen removal to the biological nutrient removal (i.e. nitrogen plus phosphorous removal) with special attention to the operational strategy design, the identification of possible reactor cycle controls or the influent composition related to the process efficiency. In such sense, also the use of ethanol as an external carbon (when low influent Carbon:Phosphorus (C:P) or Carbon:Nitrogen (C:N) ratios are presented) are studied as an alternative to maintain the BNR efficiency.

The practical guide on what to do right when biological influences cause a sequencing batch reactor to go wrong This richly illustrated, straightforward guide carries forth the legacy established by previous editions in the Wiley Wastewater Microbiology series by focusing attention on the mixed gathering of organisms cohabitating within a sequencing batching reactor (SBR), and the key roles their biology plays in this wastewater processing tank's function. With a clear, user-friendly presentation of complex subject matter, Troubleshooting the Sequence Batch Reactor first teaches plant operators how to differentiate the positive and expected organismal dynamics present in optimal SBR performance from the negative and damaging ones that create unhealthy sludge, and a stoppage in SBR operations. Next, Troubleshooting the Sequence Batch Reactor delivers all the tools necessary to get an SBR back on track and running safely. In this book you'll get: Short-course situations tested by the author for the past fifteen years Accessible material aimed at operators instead of design and consulting engineers Essential information for understanding biological conditions such as aerobic, anoxic, and anaerobic/fermentative at the treatment process Examination of the properties of protozoa (single-celled) and metazoa (multi-celled) organisms, and their significance in wastewater treatment Devoid of overwhelming scientific jargon, chemical equations, and kinetics, this book simplifies details to provide quick instruction for plant operators on how to make more informed day-to-day process control decisions, how to troubleshoot confidently when SBR conditions become compromised, and how to act decisively when the problem is ultimately identified.

Contents - List of Tables - List of Figures - PART ONE: NITRIFICATION - Chapter 1 Introduction - Chapter 2 Nitrogenous and Phosphorous Compounds - Chapter 3 Nitrification: The Basics - Chapter 4 Nitrifying Bacteria - Chapter 5 Nitrification and Limiting Factors - Chapter 6 Promoting Nitrification - PART TWO: DENITRIFICATION - Chapter 7 Denitrification: The Basics - Chapter 8 Denitrifying Bacteria - Chapter 9 Denitrification and Limiting Factors - PART THREE: BIOLOGICAL PHOSPHORUS REMOVAL - Chapter 10 Biological Phosphorus Removal: The Basics - Chapter 11 EBPR: Process Control - Abbreviations and Acronyms - Glossary - Bibliography - Biological nutrient removal (BNR), the removal of nitrogen and phosphorus from wastewater, is a complex process. Although the activated sludge process is an efficient technology for the removal of biochemical oxygen demand (BOD) and total suspended solids (TSS), it provides less-than-optimal conditions for the removal of nitrogen and phosphorus, and presents numerous challenges to the operator trying to satisfy the many requirements for several different groups of bacteria. In addition to satisfying the requirements there are numerous, highly variable operational conditions that impact BNR. These conditions include: changes in strength and composition of the wastewater, alkalinity and pH, temperature, and presence of inhibitory and toxic wastes. Even fluctuations in flows, especially from inflow and infiltration, can adversely impact the aerobic, anoxic, and anaerobic conditions needed for successful BNR. Of the three treatment processes, nitrification, denitrification, and enhanced biological removal, nitrification is often the most difficult to achieve. Therefore, a large portion of this book reviews nitrification. Operators of the activated sludge process need to understand the basic biological, chemical, and physical requirements for BNR in order to improve the performance of these treatment processes. An Operator's Guide to Biological Nutrient Removal (BNR) in the Activated Sludge Process is intended to help operators in the monitoring, troubleshooting, and process control of BNR. Numerous tables and figures are included in the book to help the operator understand the biological and chemical reactions that are involved in BNR processes and how the reactions can be monitored for process control. Design of BNR processes is not addressed in this book. Design is addressed in numerous engineering publications. The book serves to help operators achieve permit compliance for nitrogen and phosphorus discharge limits and obtain cost-effective operation. -

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.