Download or read book Development and Implementation of Household Level Intermittent Slow Sand Filters for Rural Areas to Mitigate Water related Diseases written by Sangya-Sangam Kumari Tiwari and published by . This book was released on 2008 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Progress in Slow Sand and Alternative Biofiltration Processes written by Rolf Gimbel and published by IWA Publishing. This book was released on 2006-03-31 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Slow sand filtration is typically cited as being the first "engineered" process in drinking-water treatment. Proven modifications to the conventional slow sand filtration process, the awareness of induced biological activity in riverbank filtration systems, and the growth of oxidant-induced biological removals in more rapid-rate filters (e.g. biological activated carbon) demonstrate the renaissance of biofiltration as a treatment process that remains viable for both small, rural communities and major cities. Biofiltration is expected to become even more common in the future as efforts intensify to decrease the presence of disease-causing microorganisms and disinfection by-products in drinking water, to minimize microbial regrowth potential in distribution systems, and where operator skill levels are emphasized. Recent Progress in Slow Sand and Alternative Biofiltration Processes provides a state-of-the-art assessment on a variety of biofiltration systems from studies conducted around the world. The authors collectively represent a perspective from 23 countries and include academics, biofiltration system users, designers, and manufacturers. It provides an up-to-date perspective on the physical, chemical, biological, and operational factors affecting the performance of slow sand filtration (SSF), riverbank filtration (RBF), soil-aquifer treatment (SAT), and biological activated carbon (BAC) processes. The main themes are: comparable overviews of biofiltration systems; slow sand filtration process behavior, treatment performance and process developments; and alternative biofiltration process behaviors, treatment performances, and process developments.
Download or read book Intermittent Slow Sand Filters written by Magdalena Pachocka and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As many as 500,000 people in developing countries rely on an intermittent slow sand filter, called the BioSand filter to provide safe drinking water. However, it has been shown that BioSand filters do not remove all of the pathogens. The mechanisms of water purification in slow sand filtration have not been clearly understood until this day. In order to successfully influence intermittent slow sand filters performance we need to have a full understanding of removal processes that govern their efficiency. In the first part of this study pathogen removal mechanisms in intermittent slow sand filtration were investigated. In the second part of this study the effect on pathogen removal of a zero-valent iron-sand mixed layer, placed at the bottom of an intermittent slow sand filter was investigated. A series of experiments was performed on sand columns ripened with creek water. It was shown that the majority of E.coli was removed during filtration through the schmutzdecke, while the residence time in the biologically active layer did not have a significant effect on its removal. Quite to the contrary, the majority of MS-2 virus was removed with the residence time in the biologically active layer while the filtration through the schmutzdecke did not have significant affect on its removal. Clearly, two different mechanisms govern bacteria and virus removal in intermittent slow sand filtration. The EDX analysis of the schmutzdecke material revealed that it was primarily composed of O, C, Si, Al, Fe, Ca, and Mn. The zeta potential analysis showed that the schmutzdecke was neutral in charge and was composed of positively, neutrally and negatively charged particles. It was determined that a flocculation process was not a likely mechanism of either E.coli or MS-2 removal in intermittent slow sand filtration. The disturbance of the schmutzdecke had a significant impact on E.coli removal but only a slight effect on MS-2 removal. The intricate internal structure of the schmutzdecke might affect bacteria removal by an increase in rate of collisions. The disturbance of the schmutzdecke may cause the water to bypass the treatment in the schmutzdecke "network" of polymeric strands. It was concluded that an additional treatment step is needed in order to efficiently remove viruses; that the residence time in the schmutzdecke affects the quality of the effluent.; that the disturbance of the schmutzdecke might lead to a significant compromise in water quality and thus should be avoided; and that the addition of Al or Fe into the filter influent might benefit the pathogen removal efficiency. In the second part of the study an intermittent slow sand filter was amended with a zero-valent iron-sand mixture at the bottom of the column in order to improve its performance, especially virus removal. In the first challenge experiment the ZVI amended filter removed 100% of both E.coli and MS-2. Although, in the second challenge experiment the zero-valent iron-sand layer caused a decrease in E.coli/MS-2 concentration for unknown reasons, both E.coli and MS-2, exhibited breakthrough in the effluent. The ZVI powder can be obtained by sieving iron filings which are a waste byproduct of iron industry. Therefore, it is readily available to communities in developing countries. It was shown that use of ZVI in an intermittent slow sand filter can greatly improve its safety. However, the mechanisms responsible for this benefit and limitations of ZVI are not yet explained and deserve to be investigated.
Download or read book Slow Sand Filtration written by Nigel Jonathon Douglas Graham and published by . This book was released on 1988 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water and Sanitation Related Diseases and the Changing Environment written by Janine M. H. Selendy and published by John Wiley & Sons. This book was released on 2019-02-06 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: The revised and updated second edition of Water and Sanitation Related Diseases and the Changing Environment offers an interdisciplinary guide to the conditions responsible for water and sanitation related diseases. The authors discuss the pathogens, vectors, and their biology, morbidity and mortality that result from a lack of safe water and sanitation. The text also explores the distribution of these diseases and the conditions that must be met to reduce or eradicate them. The text includes contributions from authorities from the fields of climate change, epidemiology, environmental health, environmental engineering, global health, medicine, medical anthropology, nutrition, population, and public health. Covers the causes of individual diseases with basic information about the diseases and data on the distribution, prevalence, and incidence as well as interconnected factors such as environmental factors. The authors cover access to and maintenance of clean water, and guidelines for the safe use of wastewater, excreta, and grey water, plus examples of solutions. Written for students, and professionals in infectious disease, public health and medicine, chemical and environmental engineering, and international affairs, the second edition of Water and Sanitation Related Diseases and the Changing Environment isa comprehensive resource to the conditions responsible for water and sanitation related diseases.
Download or read book Progress in Slow Sand and Alternative Biofiltration Processes written by Nobutada Nakamoto and published by IWA Publishing. This book was released on 2014-05-14 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a state-of-the-art assessment on a variety of biofiltration water treatment systems from studies conducted around the world. The authors collectively represent a perspective from 23 countries and include academics/researchers, biofiltration system users, designers, and manufacturers. Progress in Slow Sand and Alternative Biofiltration Processes - Further Developments and Applications offers technical information and discussion to provide perspective on the biological and physical factors affecting the performance of slow sand filtration and biological filtration processes. Chapters were submitted from the 5th International Slow Sand and Alternative Biological Filtration Conference, Nagoya, Japan in June 2014. Authors: Nobutada Nakamoto, Shinshu University, Japan, Nigel Graham, Imperial College London, UK, M. Robin Collins, University of New Hampshire, Durham, NH, USA and Rolf Gimbel,Universität Duisburg, Essen, Germany.
Download or read book Slow Sand Filtration written by American Water Works Association and published by . This book was released on 1994 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Slow Sand Filtration written by American Society of Civil Engineers. Task Committee on Slow Sand Filtration and published by American Society of Civil Engineers. This book was released on 1991 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarises current practice regarding slow sand filtration in the US. It examines topics such as the biological and physical mechanisms, appropriate water quality, micro-organisms removal, filter design, construction, operation, maintenance, costs and pilot studies.
Download or read book Environmental Health Engineering in the Tropics written by Sandy Cairncross and published by Routledge. This book was released on 2018-11-12 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fully updated third edition of the classic text, widely cited as the most important and useful book for health engineering and disease prevention, describes infectious diseases in tropical and developing countries, and the effective measures that may be used against them. The infections described include the diarrhoeal diseases, the common gut worms, Guinea worm, schistosomiasis, malaria, Bancroftian filariasis and other mosquito-borne infections. The environmental interventions that receive most attention are domestic water supplies and improved excreta disposal. Appropriate technology for these interventions, and also their impact on infectious diseases, are documented in detail. This third edition includes new sections on arsenic in groundwater supplies and arsenic removal technologies, and new material in most chapters, including water supplies in developing countries and surface water drainage.
Download or read book Intermittent Sand Filtration of Household Wastewater Under Field Conditions written by David K. Sauer and published by . This book was released on 1975 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Water Filtration for Rural Areas written by N. C. Thanh and published by . This book was released on 1982 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Filtration Practices written by Gary S. Logsdon and published by American Water Works Association. This book was released on 2011-01-12 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water operators will find a wealth of hands-on information on the operation and maintenance of pretreatment, rapid-rate granular media filtration, slow-sand filtration, and diatomaceous-earth filtration systems in this book. This practical guide provides recommended procedures for operating, monitoring, and maintaining all types of filters used for conventional water treatment. These procedures are tested and time-proven by hundreds of water utilities and filtration experts to provide high filter efficiency, excellent water quality, long filter runs and minimum downtime. The book also gives advice on what not to do-and why-so you can avoid water quality problems, filter damage, and treatment problems in the future.
Download or read book Advances in Slow Sand and Alternative Biological Filtration written by Nigel Graham and published by Wiley. This book was released on 1996-07-10 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: Slow sand filtration is credited with being the first drinking water treatment process utilised to improve the quality of water in both modern Europe and the USA. Within the last 10 years, there has been a renaissance of interest in the potential use of enhanced processes of slow sand filtration throughout the world, especially for small and rural communities, and it continues to be the primary treatment process for many major European cities. The book deals with the latest research developments in slow sand and alternative biological filtration processes for drinking water treatment, including advances in the understanding of the fundamental mechanisms of the processes. In addition, progress in the techniques of operation and upgrading of the processes are described, with case studies from around the world. The principal themes of the book are: General overview; Removal of Natural Organic Matter (NOM), Biodegradable Organic Carbon (BOC) and Ozonation by-products; Biofilter media characteristics; Influence of process design variables and modifications; Modelling process performance; Pre-treatment applications; Operational experience and cleaning; and Upgrading treatment processes. The book also has an international perspective with case-studies from around the world.
Download or read book Manual of Design for Slow Sand Filtration written by and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sustainable Drinking Water Treatment for Small Communities Using Multistage Slow Sand Filtration electronic Resource written by Cleary, Shawn A and published by University of Waterloo. This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Slow sand filtration is a proven and sustainable technology for drinking water treatment in small communities. The process, however, is sensitive to lower water temperatures that can lead to decreased biological treatment, and high raw water turbidity levels that can lead to premature clogging of the filter and frequent cleaning requirements, resulting in increased risk of pathogen breakthrough. Multistage filtration, consisting of roughing filtration followed by slow sand filtration, can overcome these treatment limitations and provide a robust treatment alternative for surface water sources of variable water quality in northern climates, which typically experience water temperatures ranging down to 2C̊. Prior to this study, however, multistage filtration had yet to be systematically challenged in colder climates, including testing of its performance under increased hydraulic loadings and elevated influent turbidity together with cold water conditions. The primary goal of this research was to demonstrate the reliability of multistage filtration for small communities in northern climates with reference to the Ontario Safe Drinking Water Act. In this research, testing was conducted on two different pilot multistage filtration systems and fed with water from the Grand River, a municipally and agriculturally impacted river in Southern Ontario. One system featured pre-ozonation and post-granular activated carbon (GAC) stages, and shallower bed depths in the roughing filter and slow sand filter. The other system featured deeper bed depths in the roughing filter and slow sand filter, two parallel roughing filters of different design for comparison, and a second stage of slow sand filtration for increased robustness. Removal of turbidity, total coliforms, and fecal coliforms under a range of influent turbidities (1 to>100 NTU), water temperatures (~2 to 20C̊), and hydraulic loading rates (0.2 to 0.8 m/h) were investigated. In addition, the slow sand filters in each pilot system were challenged with high concentrations (~10¡ oocyst/L) of inactivated Cryptosporidium parvum oocysts. The performance of both pilot multistage filtration systems was highly dependent on the biological maturity of the system and its hydraulic loading rate. In a less mature system operating in cold water conditions (5C̊), effluent turbidity was mostly below 0.5 NTU during periods of stable influent turbidity (no runoff events) and a hydraulic loading of 0.4 m/h, however, runoff events of high influent turbidity (50 NTU), increased hydraulic loadings (0.6 m/h), and filter cleaning occasionally resulted in effluent turbidity above 1 NTU. Furthermore, in a less mature system operating during runoff events of high turbidity, reducing the hydraulic loading rate to 0.2 m/h was important for achieving effluent turbidity below 1 NTU. However, in a more mature system operating in warm water conditions (19-22C̊), effluent turbidity was consistently below 0.3 NTU at a hydraulic loading rate of 0.4 m/h, and below 0.5 NTU at 0.8 m/h, despite numerous events of high influent turbidity (>25 NTU). It remains to be seen whether this performance could be sustained in colder water temperatures with a fully mature filter. Removal of coliform bacteria was occasionally incomplete in a less mature multistage system, whereas, in a more mature system operating in warm water conditions (>9C̊), removal was complete in all measurements. Furthermore, the average removal of Cryptosporidium was greater than 2.5 logs in both systems (with hydraulic loading rates ranging from 0.4 to 0.8 m/h) and improved with increased filter maturity. Each individual stage of the multistage system was an important treatment barrier in the overall process of turbidity and pathogen removal. The roughing filter was not only important for protecting the slow sand filter from solids loading and increasing its run length, but was also a significant contributor to coliform removal when the system was less mature. Removal of turbidity was significantly improved when the roughing filter was more mature, suggesting that biological treatment was an important treatment mechanism in the roughing filter. Although pre-ozonation was used mainly for the removal of organic carbon and colour, it achieved complete removal of coliform bacteria and was also suspected to be important for enhanced removal of turbidity. The second slow sand filter in series provided additional robustness to the process by reducing effluent turbidity to below 1 NTU during cold water runoff events of high turbidity and increased hydraulic loadings (0.6 m/h), while achieving effluent below 0.3 NTU during normal periods of operation. It also provided additional removals of coliforms under challenging operating conditions, and contributed an additional average removal of Cryptosporidium of 0.8 logs, which resulted in cumulative removal of 3.7 logs, approximately 1 log greater than all the other challenge tests. Collectively, the entire multistage system performed well with water temperatures ranging down to 2C̊, limited filter maturity, elevated raw water turbidities, and increased hydraulic loading rates. Its ability to meet the current Ontario turbidity regulations and greater than 2 log removal of Cryptosporidium over a range of operating conditions, with little or no process adjustment, is a testament to the robustness and minimal maintenance requirements of the process, which are desirable attributes for small water systems that are often located in rural areas. While this research demonstrated the performance of multistage filtration using pilot scale testing, it is important to note that full-scale plants tend to produce significantly better results than pilot facilities, due to long term biological maturation of the system. Overall, multistage filtration is a sustainable and cost-effective technology that, through this research, appears to be a safe, reliable, and robust treatment alternative for small and non-municipal water systems in North America and the developing world. Further, based on its performance with challenging influent water quality and cold water conditions, multistage filtration holds particular promise for small communities in northern climates that are required to meet safe drinking water regulations, but are dependent on surface water sources of variable water quality and temperatures.
Download or read book Management of Legionella in Water Systems written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2020-02-20 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: Legionnaires' disease, a pneumonia caused by the Legionella bacterium, is the leading cause of reported waterborne disease outbreaks in the United States. Legionella occur naturally in water from many different environmental sources, but grow rapidly in the warm, stagnant conditions that can be found in engineered water systems such as cooling towers, building plumbing, and hot tubs. Humans are primarily exposed to Legionella through inhalation of contaminated aerosols into the respiratory system. Legionnaires' disease can be fatal, with between 3 and 33 percent of Legionella infections leading to death, and studies show the incidence of Legionnaires' disease in the United States increased five-fold from 2000 to 2017. Management of Legionella in Water Systems reviews the state of science on Legionella contamination of water systems, specifically the ecology and diagnosis. This report explores the process of transmission via water systems, quantification, prevention and control, and policy and training issues that affect the incidence of Legionnaires' disease. It also analyzes existing knowledge gaps and recommends research priorities moving forward.
Download or read book Intermittent Sand Filtration to Upgrade Existing Wastewater Treatment Facilities written by Gary R. Marshall and published by . This book was released on 1974 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
