Adsorptive Removal Of Manganese Arsenic And Iron From Groundwater

Day-to-day water management is challenged by meteorological extremes, causing floods and droughts. Often operational water managers are informed too late about these upcoming events to be able to respond and mitigate their effects, such as by taking flood control measures or even requiring evacuation of local inhabitants. Therefore, the use of weather forecast information with hydrological models can be invaluable for the operational water manager to expand the forecast horizon and to have time to take appropriate action. This is called Anticipatory Water Management. Anticipatory actions may have adverse effects, such as when flood control actions turn out to have been unnecessary, because the actual rainfall was less than predicted. Therefore the uncertainty of the forecasts and the associated risks of applying Anticipatory Water Management have to be assessed. To facilitate this assessment, meteorological institutes are providing ensemble predictions to estimate the dynamic uncertainty of weather forecasts. This dissertation presents ways of improving the end-use of ensemble predictions in Anticipatory Water Management.

Part of Metals and Related Substances in Drinking Water Set - buy all five books together to save over 30%! The EU Drinking Water Directive sets a range of standards for metals and related substances in drinking water, many of which are concerned with health protection. A number of these standards are very stringent and require compliance to be assessed at the point of use. Because of the difficulties associated with monitoring, historic practices in many countries have concentrated on the quality of water within the distribution network. As a result, the magnitude of problems with some metals and related substances in drinking water is not fully appreciated in all European countries, and the extent and nature of corrective actions differ widely. This Best Practice Guide on Metals Removal From Drinking Water By Treatment describes drinking water standards and regulations, and explains the impact of a range of water treatment processes on metal levels in drinking water. Its objectives are to provide a basis for assessing the extent of problems and to identify appropriate water treatment options. The Guide provides a reasoned guide to selection of key water treatment processes. Each chapter focuses on a specific water treatment process and has been written by experts in that particular process. Best Practice Guide on Metals Removal From Drinking Water By Treatment provides practice-based knowledge for water engineers and scientists in large and small water utilities, regulatory agencies, health agencies and local municipalities (from cities through to small rural communities). It also supports university level teaching in degree schemes that relate to water management. This Guide is one of a series produced by the International Water Association’s Specialist Group on Metals and Related Substances in Drinking Water. The series is an up-to-date compilation of a range of scientific, engineering, regulatory and operational issues concerned with the control and removal of metals from drinking water.

Contamination of groundwater with arsenic is being considered a pervasive and critical issue in recent years. Large areas in India, Bangladesh, South East Asia, and other parts of the world are suffering from this problem. Arsenic Removal from Contaminated Groundwater presents a comprehensive discussion on various important issues, including state-of-the-art arsenic removal technologies, preparation and performance analysis of laterite, and scale-up issues and design of a household filter. It also expounds the potentiality of raw laterite and treated laterite as low-cost arsenic adsorbents. The efficiency of adsorbent capacity is evaluated using real arsenic contaminated groundwater collected from an affected area in West Bengal, India. The topic is an emerging area and most of the work presented has the potential of field application.

In The Netherlands, Belgium and other European countries, manganese is removed by conventional groundwater treatment with aeration and rapid (sand) filtration. Such a treatment process is easy to operate, cost effective and sustainable, because it does not make use of strong oxidants such as O3, Cl2, ClO2 and KMnO4 with the associated risk of by-product formation and over or under dosing. However, application of aeration-filtration is also facing drawbacks, especially the long ripening time of filter media. Due to the long ripening time, water companies have to waste large volumes of treated water, making this process less sustainable. Also, costs associated with filter media ripening (man power, electricity, operational and analysis costs) are high. Therefore decreasing the filter ripening time, regarding manganese removal is a big issue. Although already extended research has been carried out into manganese removal, the controlling mechanisms, especially of the start up face of filter media ripening, are not fully understood yet. The emphasis of this thesis is to provide a better understanding of the mechanisms involved in the ripening of virgin filter media, regarding manganese removal and how to shorten or completely eliminate the long ripening period of filters with virgin material. This thesis therefore highlights the role of the formation of a manganese oxide coating on virgin filter media. Characterization and identification revealed that the responsible manganese oxide for an effective manganese removal was Birnessite. It was found that Birnessite, formed at the beginning of the ripening process was of a biological origin. Based on the knowledge that manganese removal in conventional groundwater treatment is initiated biologically, long ripening times may be reduced by creating conditions favouring the growth of manganese oxidizing bacteria, e.g., by limiting the back wash frequency and / or intensity. Additionally, this thesis also shows that the use of freshly prepared manganese oxide, containing Birnessite, can completely eliminate filter media ripening time.

Interest in arsenic in ground water has greatly increased in the past decade because of the increased awareness of human health effects and the costs of avoidance or treatment of ground water supplies used for consumption. The goal of this book is to provide a description of the basic processes that affect arsenic occurrence and transport by providing sufficient background information on arsenic geochemistry and descriptions of hi- arsenic ground water, both affected and unaffected by human activity. An understanding of thermodynamics, adsorption, and the speciation of arsenic in solid phases, which are described in first three chapters, is needed to predict the fate of arsenic in ground water systems. Large-scale and deep movement of ground water can and has redistributed arsenic in the near surface environment, as described in the next two chapters. These large-scale systems can affect large volumes of both ground water and surface water, such as in the Yellowstone system, and can produce mineralised zones that subsequently release arsenic to ground water supplies. Regional identification of high-arsenic ground water and its consumption as described in the next three chapters clearly demonstrates a need for increased wat- quality monitoring, particularly in south and southeast Asia. Chapters 9-11 provide examples of high arsenic ground water associated with sulfide mineral oxidation and alkaline conditions. Finally, smaller scale studies of the effects of human activities that have produced high-arsenic ground water and methods for attenuation of ground water are presented.