This work investigated two different approaches to optimize biological sulphate reduction in order to develop a process control strategy to optimize the input of an electron donor and to study how to increase the feasibility of using a cheap carbon source. Feast/famine regimes, applied to design the control strategy, were shown to induce the accumulation of storage compounds in the sulphate reducing biomass. This study showed that delays in the response time and a high control gain can be considered as the most critical factors affecting a sulphide control strategy in bioreactors. The delays are caused by the induction of different metabolic pathways in the anaerobic sludge, including the accumulation of storage products. On this basis, a mathematical model was developed and validated. This can be used to develop optimal control strategies. In order to understand the microbial pathways in the anaerobic oxidation of methane coupled to sulphate reduction (AOM-SR), diverse potential electron donors and acceptors were added to in vitro incubations of an AOM-SR enrichment at high pressure. Acetate was formed in the control group, probably resulting from the reduction of CO2. These results support the hypothesis that acetate may serve as an intermediate in the AOM-SR process.

The main objective of this research was to optimize the electron donor supply in sulphate reducing bioreactors treating sulphate rich wastewater. Two types of electron donor were tested: lactate and slow release electron donors such as carbohydrate based polymers and lignocellulosic biowastes. Biological sulphate reduction was evaluated in different bioreactor configurations: the inverse fluidized bed, sequencing batch and batch reactors. The reactors were tested under steady-state, high-rate and transient-state feeding conditions of electron donor and acceptor, respectively. The results showed that the inverse fluidized bed reactor configuration is robust and resilient to transient and high-rate feeding conditions at a hydraulic retention time as low as 0.125 d. The biological sulphate reduction was limited by the COD:sulphate ratio ( 82% either using carbohydrate based polymers or lignocellulosic bio-wastes, in batch bioreactors. The biological sulphate reduction was limited by the hydrolysis-fermentation rate and by the complexity of the slow release electron donors.

This work investigated two different approaches to optimize biological sulphate reduction: to develop a process control strategy to optimize the input of an electron donor and the applicability of a cheap carbon source, i.e., methane. For the design of a control strategy that uses the organic loading rate (OLR) as control input, feast and famine behaviour conditions were applied to a sulphate reducing bioreactor to excite the dynamics of the process. Such feast/famine regimes were shown to induce the accumulation of carbon, and possibly sulphur, storage compounds in the sulphate reducing biomass. This study showed that delays in the response time and a high control gain can be considered as the most critical factors affecting the application of a sulphide control strategy in bioreactors. The delays are caused by the induction of different metabolic pathways in the anaerobic sludge including the accumulation of storage products. Polyhydroxybutyrate (PHB) and sulphate were found to accumulate in the biomass present in the inversed fluidized bed used in this study, and consequently, they were considered to be the main storage compounds used by SRB. On this basis a mathematical model was developed which showed a good fit between experimental and simulated data giving further support to key role of accumulation processes. In order to understand the microbial pathways in the anaerobic oxidation of methane coupled to sulphate reduction (AOM-SR) diverse potential electron donors and acceptors were added to in vitro incubations of an AOM-SR enrichment at high pressure with several co-substrates. The AOM-SR is stimulated by the addition of acetate which has not been reported for any other AOM-SR performing communities. In addition, acetate was formed in the control group probably resulting from the reduction of CO2. These results support the hypothesis that acetate may serve as an intermediate in the AOM-SR process, at least in some groups of anaerobic methanotrophs (ANME) and sulphate reducing bacteria.

This work investigated two different approaches to optimize biological sulphate reduction in order to develop a process control strategy to optimize the input of an electron donor and to study how to increase the feasibility of using a cheap carbon source. Feast/famine regimes, applied to design the control strategy, were shown to induce the accumulation of storage compounds in the sulphate reducing biomass. This study showed that delays in the response time and a high control gain can be considered as the most critical factors affecting a sulphide control strategy in bioreactors. The delays are caused by the induction of different metabolic pathways in the anaerobic sludge, including the accumulation of storage products. On this basis, a mathematical model was developed and validated. This can be used to develop optimal control strategies. In order to understand the microbial pathways in the anaerobic oxidation of methane coupled to sulphate reduction (AOM-SR), diverse potential electron donors and acceptors were added to in vitro incubations of an AOM-SR enrichment at high pressure. Acetate was formed in the control group, probably resulting from the reduction of CO2. These results support the hypothesis that acetate may serve as an intermediate in the AOM-SR process.

The first edition of this book was published in 2008 and it went on to become IWA Publishing’s bestseller. Clearly there was a need for it because over the twenty years prior to 2008, the knowledge and understanding of wastewater treatment had advanced extensively and moved away from empirically-based approaches to a fundamental first-principles approach based on chemistry, microbiology, physical and bioprocess engineering, mathematics and modelling. However the quantity, complexity and diversity of these new developments was overwhelming for young water professionals, particularly in developing countries without readily available access to advanced-level tertiary education courses in wastewater treatment. For a whole new generation of young scientists and engineers entering the wastewater treatment profession, this book assembled and integrated the postgraduate course material of a dozen or so professors from research groups around the world who have made significant contributions to the advances in wastewater treatment. This material had matured to the degree that it had been codified into mathematical models for simulation with computers. The first edition of the book offered, that upon completion of an in-depth study of its contents, the modern approach of modelling and simulation in wastewater treatment plant design and operation could be embraced with deeper insight, advanced knowledge and greater confidence, be it activated sludge, biological nitrogen and phosphorus removal, secondary settling tanks, or biofilm systems. However, the advances and developments in wastewater treatment have accelerated over the past 12 years since publication of the first edition. While all the chapters of the first edition have been updated to accommodate these advances and developments, some, such as granular sludge, membrane bioreactors, sulphur conversion-based bioprocesses and biofilm reactors which were new in 2008, have matured into new industry approaches and are also now included in this second edition. The target readership of this second edition remains the young water professionals, who will still be active in the field of protecting our precious water resources long after the aging professors who are leading some of these advances have retired. The authors, all still active in the field, are aware that cleaning dirty water has become more complex but that it is even more urgent now than 12 years ago, and offer this second edition to help the young water professionals engage with the scientific and bioprocess engineering principles of wastewater treatment science and technology with deeper insight, advanced knowledge and greater confidence built on stronger competence.

The scope of this comprehensive new edition of Handbook of Biological Wastewater Treatment ranges from the design of the activated sludge system, final settlers, auxiliary units (sludge thickeners and digesters) to pre-treatment units such as primary settlers and UASB reactors. The core of the book deals with the optimized design of biological and chemical nutrient removal. The book presents the state-of-the-art theory concerning the various aspects of the activated sludge system and develops procedures for optimized cost-based design and operation. It offers a truly integrated cost-based design method that can be easily implemented in spreadsheets and adapted to the particular needs of the user. Handbook of Biological Wastewater Treatment: Second Edition incorporates valuable new material that improves the instructive qualities of the first edition. The book has a new structure that makes the material more readily understandable and the numerous additional examples clarify the text. On the website www.wastewaterhandbook.com three free excel design spreadsheets for different configurations (secondary treatment with and without primary settling and nitrogen removal) can be downloaded to get the reader started with their own design projects. New sections have been added throughout: to explain the difference between true and apparent yield while the section on the F/M ratio, and especially the reasons not to use it, has been expanded; to demonstrate the effect of the oxygen recycle to the anoxic zones on both the denitrification capacity and the concept of available nitrate is explained in more detail. the latest developments on the causes and solution to sludge bulking and scum formation to show the rapid developments of innovative nitrogen removal and sludge separation problems the anaerobic pre-treatment section is completely rewritten based on the experiences obtained from an extensive review of large full-scale UASB based sewage treatment plants a new section on industrial anaerobic wastewater treatment three new appendices have been added. These deal with the calibration of the denitrification model, empirical design guidelines for final settler design (STORA/STOWA and ATV) and with the potential for development of denitrification in the final settler. A new chapter on moving bed biofilm reactors Handbook of Biological Wastewater Treatment: Second Edition is written for post graduate students and engineers in consulting firms and environmental protection agencies. It is an invaluable resource for everybody working in the field of wastewater treatment. Lecturer support material is available when adopted for university courses. This includes course material for the first 7 modules in the form of PDF printouts and an exercise file with questions and answers and a symbol list. Authors: Prof. dr. ir. A.C. van Haandel, Federal University of Campina Grande - Brazil and Ir. J.G.M. van der Lubbe, Biothane Systems International - Veolia, The Netherlands

Environmental Technologies to Treat Sulfur Pollution: Principles and Engineering provides a definitive and detailed discussion of state-of-the-art environmental technologies to treat pollution by sulfurous compounds of wastewater, off-gases, solid waste, soils and sediments. Special attention is given to novel bioremediation techniques that have been developed over the last 10 years. Information density is unique owing to the many figures and graphs (150), tables (over 80) and over 1500 cited literature references. A detailed subject index helps the reader to find their way through the different technological applications, making it the perfect reference work for professionals and consultants dealing with sulfur-related environmental (bio)-technologies. Contents Part I - The sulfur cycle Part II - Technologies to Desulfurise Resources Part III - Treatment of Waters Polluted by Sulfurous Compounds Part IV - Treatment of Gases Polluted by Sulfurous Compounds Part V - Treatment of Soils and Sediments Polluted by Sulfurous Compounds Part VI - Other Applications of Sulfur Cycle: Bioconversions in Environmental Engineering Part VII - Problems Related to Sulfur Cycle: Bioconversions