One of the most reliable alternative solutions to water shortage and scarcity in urban areas is potable reuse of what would otherwise be considered "waste" water. The combination of low and high-pressure membrane processes is the favoured technology for direct and indirect potable water recycling due to the very high water quality produced. Despite the fact that membrane technology is well established, membrane fouling remains a major challenge affecting plant operation technically and economically. This thesis aims to contribute to the understanding of membrane fouling in water reuse by investigating the importance of the feed water quality on fouling development and the impact of the fouling on the treated water quality. In order to achieve these objectives, it was important to develop better knowledge of the impact of feed water quality on the membrane process. The organic composition of the effluents was successfully differentiated with the use of advanced analytical tools such as fluorescence excitation emission matrix (EEM) and liquid chromatography-organic carbon detection (LC-OCD). To evaluate water quality impact on membrane fouling, a membrane pilot unit consisting of ultrafiltration and a two stage reverse osmosis train was operated on two different sites. Different monochloramine dosages (0 to 2 mg/L NH2Cl) were applied and their impact on RO membrane performance was studied in order to provide recommendations for plant design.

Pollution of water sources with emerging contaminants (micropollutants) is a fact known worldwide. Although the risks of micropollutants in sources of water are partly recognized, interpretation of consequences are controversial; thus, the future effects of altered water with micropollutants remains uncertain and may constitute a point of conc

The book covers the subject of membrane bioreactors (MBR) for wastewater treatment, dealing with municipal as well as industrial wastewaters. The book details the 3 types of MBR available and discusses the science behind the technology, their design features, operation, applications, advantages, limitations, performance, current research activities and cost. As the demand for wastewater treatment, recycling and re-use technologies increases, it is envisaged that the membrane separation bioreactor will corner the market. Contents Membrane Fundamentals Biological Fundamentals Biomass Separation Membrane Bioreactors Membrane Aeration and Extractive Bioreactors Commercial Membrane Bioreactor Systems Membrane Bioreactor Applications Case Studies

Reusing wastewater can assist in solving water shortage problems, reduce the amount of wastewater discharged to surface water bodies and, by extension, alleviate its adverse effects on humans and the environment. Organics found in wastewater can be removed through biological treatment, however, if secondary effluent is to be reused for potable or some nonpotable applications, some form of advanced treatment is required. Membranes are often used to further treat these effluents for water reuse as they require only a small footprint and can provide a high quality treated water. They are also robust as is relates to dealing with feed waters of varying composition. However, due to the accumulation of rejected contaminants and certain natural organic matter (NOM) constituents on membrane surfaces and within pores, fouling can be an important shortcoming of this technology. Small improvements in the reduction of foulants can translate into substantial improvements in production quantity and cost savings. As such, it is worth the investment of time and research into common pre-treatment methods to identify technologies that can reduce foulant accumulation on membranes. The primary objective of this study was to extend previous research which investigated the use of ultrafiltration (UF) membranes for secondary effluent treatment for water reuse purposes. The most appropriate UF pre-treatment method was identified by comparing three different pre-treatment process modes (biofiltration, in-line coagulation, and a combination of the two processes). In parallel, the primary UF membrane foulant types found in a secondary effluent with high biopolymer content were identified, as well as those removed by the pre-treatment methods used in this research. In this study, aerobic biofilters typically used in drinking water treatment, were investigated for improving the characteristics of Waterloo Wastewater Treatment Plant treated secondary effluent for reuse. Two biofilters, one containing sand and the other containing anthracite, were operated under identical conditions (empty bed contact time [EBCT] of 60 min & hydraulic loading rate [HLR] of 0.75 m/h). Four different coagulants (alum, polyaluminum chloride [PACl], ferric chloride, and ferric sulfate) with a no coagulant control and two different dosages (0.5 and 5.0 mg/L) of each were investigated for their potential to remove UF foulants. To investigate the effect of combining in-line coagulation prior to biofiltration for improving UF performance, one biofilter (containing anthracite media) and one coagulant (1.0 mg/L ferric sulfate) were selected. The organic compound fractions found in secondary effluent, were quantified by Liquid Chromatography-Organic Carbon Detection (LC-OCD) analyses in all water samples before and after each treatment step. Data revealed that both biofilters reduced dissolved organic carbon (DOC), especially the high molecular weight biopolymer fraction, which was reduced by 25-30%. However, the biopolymer concentrations in the biofiltered secondary effluent were somewhat higher than in river and lake water sources, so even with these reductions the biopolymer levels in the effluent of the biofilters were higher than would typically be seen using those sources as biofilter feed. The reduction of organic compounds attributable to biodegradation occurred in the upper layer of the biofilter as confirmed by the highest consumption of dissolved oxygen and biomass concentrations at that location. The higher removals of different DOC fractions achieved by sand appear to be attributable to the increased amount of attached biomass (measured as ATP). Physical properties of secondary effluent were also improved after biofiltration, and turbidity in the effluent of the biofilters did not exceed 1.0 NTU despite influent values ranging from 1.1 to 10.3 NTU. To investigate the impact of pre-treatment methods, UF experiments were conducted with both secondary effluent (as collected from the full-scale plant) and after pre-treatment processes. To assess the development of UF fouling rates, changes in transmembrane pressure through UF runs were monitored and measured every 10 sec. Biofiltration effectively improved the performance of UF by reducing fouling development. The observed reduction in TMP was attributed to the removal of biopolymers (especially the protein component) and turbidity through biofiltration. Under the investigated conditions, sand as a biofilter media performed better than anthracite for reducing UF fouling. When the UF membrane was fed with biofilter effluents, both the reversible and irreversible fouling were correlated with biopolymer concentrations in feed water. Particulate matter was also weakly correlated with reversible fouling. In-line coagulation experiments demonstrated a sustainable reduction in both reversible and irreversible fouling, and coagulant type and dosage had a major impact in improving the performance of UF. Fouling reduction by in-line coagulation was primarily attributed to the alteration of organic composition of secondary effluent and/or the size modification of particles that contributed to membrane pore blocking. The most substantial impact of in-line coagulation was observed for the irreversible fouling reduction, which is more important for sustainable operation of membranes. The higher of the two coagulant dosages tested improved foulant removal and additional reduction of membrane reversible and irreversible fouling rates. Under the conditions investigated, ferric-based coagulants were better for UF fouling control than the aluminum-based coagulants. In-line coagulant provided additional removal of particles and organics through biofilter. In this instance it appears as if the negative surface charge of colloids and organics surface is reduced by charge neutralization resulting in larger compounds being produced and rejected by straining processes through the biofilter. In-line coagulation prior to biofiltration further improved membrane performance by reducing fouling and enhancing the removal of particles and DOC fractions (biopolymer and humic substances) through UF. Biofilter hydraulic performance was relatively unaffected by the upstream addition of coagulant. This study demonstrated that biofiltration and in-line coagulation can, under the investigated conditions, remove some treated wastewater constituents which have been associated with membrane fouling, and negatively affect other advanced treatments for water reuse. The integration of the two pre-treatment processes provided additional fouling reduction and a better UF permeate water was produced than that of the individual pre-treatments.

This book covers the topic of microplastics in water and wastewater. The chapters start with introductory issues related to the growing interest in the scientific community on microplastics and the human water cycle and point out where the microplastics could interact with water. The subsequent chapters examine evidence of the microplastic presence in freshwater, such as in both rivers and lakes, in freshwater biota, and hazardous chemicals associated with microplastics in such systems. Another set of chapters discuss the presence of microplastics in wastewater: their sources; their transfer through a wastewater treatment plant; the concentration of microplastics in effluents throughout the world; the plastic biomedia used in wastewater treatment plants and the effect on the surrounding environment of effluent wastewater pipes. These chapters also discuss the sampling methods, the sample treatment and analysis techniques used so far for microplastics in wastewater. Additionally, the presence of microplastics in sewage sludge and in soils irrigated with wastewater or fertilized with sludge are discussed. The possible impact of plastics and their additives on plants, microalgae, and humans are reviewed and presented in a critical way. Finally, a chapter summarizes all the relevant regulations and initiatives that point to the necessity of a global directive for the protection of the environment from plastic and microplastic pollution. The topic of microplastics in freshwater systems and in wastewater has scarcely been studied and requires more attention. Microplastics in Water and Wastewater aims to bring these initial findings to the attention of a broader audience and especially to operators and managers of freshwater and wastewater systems. It will also be helpful to people already aware of the marine debris problem to understand the sources of microplastics in the oceans, from freshwater systems and wastewater treatment plants.

In recent years the MBR market has experienced unprecedented growth. The best practice in the field is constantly changing and unique quality requirements and management issues are regularly emerging. Membrane Biological Reactors: Theory, Modeling, Design, Management and Applications to Wastewater Reuse comprehensively covers the salient features and emerging issues associated with the MBR technology. The book provides thorough coverage starting from biological aspects and fundamentals of membranes, via modeling and design concepts, to practitioners’ perspective and good application examples. Membrane Biological Reactors focuses on all the relevant emerging issues raised by including the latest research from renowned experts in the field. It is a valuable reference to the academic and professional community and suitable for undergraduate and postgraduate teaching in Environmental Engineering, Chemical Engineering and Biotechnology. Editors: Faisal I. Hai, University of Wollongong, Australia Kazuo Yamamoto, University of Tokyo, Japan Chung-Hak Lee, Seoul National University, Korea.