bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anaerobic Sewage Treatment
Authors: Seghezzo Lucas , Zeeman Grietje , Lettinga Gatze 
Published: July 2005

AbstractThe state‐of‐the art of the anaerobic treatment of sewage, or domestic wastewater, is presented. The chapter begins with a brief definition of sewage and a description of the main pollutants contained in it. Negative consequences of the uncontrolled discharge of raw or badly treated sewage into the environment are summarized, with emphasis on health aspects. The technologies available to treat sewage are presented, focusing on the upflow anaerobic sludge bed (UASB) reactor. Some examples of the use of UASB reactors for sewage treatment are discussed. The chapter ends with an indication of the potential of UASB reactors to contribute to the achievement of more sustainable sanitation in developing countries.
Application of Risk Assessments in Crafting Drinking Water Regulations
Authors: Macler Bruce A. 
Published: July 2005

Abstract
Assessments of adverse health outcomes and estimations of health risks from contaminants of drinking water are used at several points in the overall development of U.S. drinking water regulations. They are applied during the extensive discussions surrounding consideration of a contaminant's risk and approaches to risk mitigation, and in the required elements of National Primary Drinking Water Regulation (NPDWR) proposals, support documents, and final rules. Risk assessments are of several types with substantially different intents and characteristics. No one approach fits all applications. The type of assessment chosen depends on the application and the nature and availability of relevant data.
The regulatory process starts with the identification of a constituent as either a possible contaminant of drinking water or as having some adverse toxicological or pathogenic properties. Available health data are then collected and analyzed, leading to the possible development of a toxicological profile of adverse health outcomes and dose–response characteristics. This is then coupled with occurrence data and exposure estimates to provide an estimate of national public health impact.
Multistage Drinking Water Filtration
Authors: Rooklidge Stephen J. 
Published: July 2005

AbstractMultistage drinking water filtration is a combination of roughing filter and slow sand filter unit processes that broadens the use of these passive treatment methods to include source water whose turbidity is higher than that normally suitable for biological filtration. Slow sand filtration is one of the oldest surface water treatment techniques, but it is easily compromised by source water with high turbidity caused by erosional or meteorologic events in the upstream watershed. By providing roughing filter pretreatment, suspended solids are decreased and the biological integrity of the slow sand filter is maintained with a concomitant extension of the filtration period. Slow sand filtration is still a viable method of water treatment most suitable for raw water sources low in turbidity and suspended solids. Multistage filtration has been shown to be an efficient and effective drinking water treatment technique for source water with high turbidity, organic matter, and suspended solids.
Approaches for Securing a Water Distribution System
Authors: Hosner Marsha A. 
Published: July 2005

Abstract
The world focus on water security has been extremely heightened since the attack on the World Trade Center on September 11, 2001. The thinking behind the new focus is in response to terrorist threats on our drinking water and infrastructure in general. This heightened focus is generally a public response—citizens wanting something to be done to make them safer than they are currently. But water related security issues are not new.
The possibilities of things that could go wrong are impossible to list—a fact that points to a reality that has to be faced. There is no way to stop things from happening to your water systems. And though there are a number of things you can do to reduce the risk, the most important step to take is preparing in advance for the time when something does happen.
Nitrification of Potable Water Using Trickling Filters
Authors: Vayenas D.V. , Lyberatos Gerasimos 
Published: July 2005

Abstract

Due to the nitrogenous oxygen demand and the carcinogenic chloramines that are formed, ammonia needs to be removed from potable water before it can be consumed. Ammonia may be removed chemically or biologically. Biological ammonia removal (nitrification) is carried out by two different nitrifying bacteria,
Nitrosomonas
and
Nitrobacter
. Due to the low specific growth rates of these bacteria, high nitrification rates can be secured only in attached growth systems such as trickling filters. This allows retaining the slow‐growing nitrifiers even at high hydraulic loadings. The choice of filter medium is of great importance because it provides the surface for bacterial growth and determines the air and water flow characteristics of the filter. Recirculation may enhance nitrification in trickling filters for high hydraulic and ammonia loads, whereas iron and manganese inhibit nitrification. Modeling of nitrification in trickling filters allows proper design of the filters and prediction of their performance. Such mathematical models have been used to develop operating diagrams that may be used to ensure safe and complete nitrification of potable water for a wide range of flow rates and ammonia feed concentrations.
Design of Water Distribution Systems
Authors: Lingireddy Srinivasa , Ormsbee Lindell E. , Wood Don J. , Ramalingam D. 
Published: July 2005

AbstractThe ultimate goal of drinking water utilities is to provide adequate quantities of water to its consumers while maintaining satisfactory pressures throughout the distribution system. Efficient design of water distribution system components is an important step that allows not only achieving this goal but also enabling the utilities to provide water at affordable costs. Design of water distribution systems is a complex and tedious process. Several optimization techniques have been reported in literature to automate and reduce the complexity of the design process. However, lack of robust optimization platforms that allow specification of preferred objective functions and desired combinations of constraints and decision variables have seriously limited the use of available optimization technology for water distribution systems design. This article presents a comprehensive iterative method that makes use of a hydraulic network model for design of water distribution systems. The article describes various components of a water distribution system that would affect the design process along with a list of constraints that should be considered for efficient design. Although the procedure presented is for design of new water distribution systems, the method can be easily adapted for sizing enhancements to existing systems.
Municipal Water Supply: Ozonation
Authors: Kim Jaehong 
Published: July 2005

AbstractSince the first full‐scale application of ozone for water treatment in late 1800s, ozone has been widely used in municipal water supplies in many countries. The primary goal of the ozonation process in water treatment is often disinfection, but ozonation is also used in many other applications, including taste and odor control, color removal, oxidation of manganese and iron, flocculation enhancement, oxidation of natural organic matter (NOM) and accompanying promotion of its biodegradability, and control of chlorination byproducts (1). Recently, the application of ozone as a disinfectant has been receiving more attention because of its effectiveness in treating pathogens, such as oocysts of the protozoan parasiteCryptosporidium parvum, which have shown strong resistance to chlorine‐based disinfectants (2, 3).In water treatment, ozone can be applied either at the early stage of treatment (i.e., preozonation) or after other treatment processes, including conventional processes such as coagulation/flocculation and sedimentation. Ozone is sometimes used with hydrogen peroxide or UV to promote the formation of hydroxyl radicals in advanced oxidation processes (AOPs). Due to the increased biodegradability of organic matter after ozonation, ozonation is typically followed by biological filtration to remove biodegradable organic matter and to minimize microbial regrowth in the distribution system. Ozone decomposes relatively fast, so secondary disinfectants such as free chlorine and monochloramine are often applied after ozonation to provide residual disinfectant in the distribution system.
Ozone With Activated Carbon for Drinking Water Treatment
Authors: Ahmad Rasheed 
Published: July 2005

Abstract
Ozone is a very strong oxidant and powerful disinfectant that has been used for water treatment in many countries. In addition to its strong oxidation and disinfection properties, ozone has other beneficial effects. Ozone aids in coagulation and flocculation, acts effectively in taste and odor removal, does not produce halogenated disinfection by‐products (DBPs) except in bromide‐rich water, extends filter runs due to lower rates of head loss, and helps in removing natural organic matter in conventional treatment or in activated carbon adsorption processes. However, the use of ozone has limitations. It does not produce a persistent disinfectant residual. Ozone is relatively costly, and it produces suspected carcinogens like bromates in bromide‐rich water.
Particulate Matter Removal by Coagulation
Authors: Ahmad Rasheed 
Published: July 2005

Abstract

Coagulation is used in water treatment plants as a pretreatment step to remove particulate matter and dissolved materials, especially natural organic material (NOM). Examples of particulate matter in surface water include clay and silt particles, bacteria, viruses, and protozoan cysts such as
Giardia
and
Cryptosporidium
. NOM is formed in surface water from biodegradation and/or transformation of plant and animal material in the watershed. Although the removal of particulate matter continues to be an important reason for using coagulation, recent concern about carcinogenic by‐products has emphasized that the coagulation process must also optimize the removal of NOM to reduce the formation of disinfection by‐products.

The major purposes of coagulation include destabilizing colloidal particles, removing color and precursors of disinfection by‐products, enhancing flocculation, improving filtration, and pretreating to prolong the life of granular activated carbon contactors.
Particulate Matter Removal by Filtration and Sedimentation
Authors: Ahmad Rasheed 
Published: July 2005

Abstract
Sedimentation is the step in conventional water treatment systems that follows flocculation and precedes filtration. Its purpose is to enhance the filtration process by removing particulate matter. Sedimentation requires that the water flow through a basin at a slow enough velocity to permit the particulate matter to settle to the bottom of the basin before the water exits the basin. The equipment required for this process includes a rectangular, square, or circular settling basin. The basin includes provisions for inlet and outlet structures and a sludge collection system. In addition, sedimentation systems are optionally equipped with tube or plate settlers to improve performance.

The settling velocity of the particles or particulate matter is governed by the particle size, shape, density, and water viscosity (which varies with temperature). Stokes' law describes the terminal velocity of discrete spherical particles in a laminar flow regime. In an ideal up‐flow rectangular settling tank, all particles that have a settling velocity greater than the liquid up‐flow velocity will be captured. This up‐flow velocity is more commonly called the hydraulic overflow rate or surface loading rate. The surface overflow rate is the primary design parameter for sizing sedimentation basins. This rate is defined as the rate of inflow (
Q
) divided by the tank surface or floor area (
A
). Units are typically rated in gallons per day per square foot, gallons per minute per square foot, or cubic meters per hour per square meter. Design hydraulic overflow rates vary with the nature of the settling solids, the water temperature, and the hydraulic characteristics of the sedimentation basin.
Particulate Removal
Authors: Ahmad Rasheed 
Published: July 2005

Abstract
Particulate removal is extremely important in providing safe and aesthetically pleasing drinking water. A wide variety of particulate matter is present in raw water sources as a result of either natural events or human activities. Other particulates, mainly chemical precipitants, are created intentionally to remove other contaminants. Naturally occurring particulates are clay, silt, metal oxides, biological and organic detritus, and biota such as bacteria, viruses, protozoa, and algae. Chemical precipitants and particulate oxides, the other type of particulate, are produced when coagulants or chemical oxidants are used.
There are two categories of particulate removal process technologies in drinking water treatment: the particle alteration and particle production process and particle separation process technology. Coagulation and chemical oxidation are considered particle alteration and particle production processes. Sedimentation, filtration, flotation, and membrane processes fall under particle separation technology. For effective and complete particulate removal, a particle alteration and particle production process should be followed by a particle separation process.
Settling Tanks
Authors: Voutchkov Nikolay 
Published: July 2005

Abstract
Settling tanks (clarifiers) are key wastewater treatment facilities used for gravity separation of settleable solids contained in the wastewater. Depending on their geometrical shape settling tanks could be rectangular or circular. Clarifier shape most suitable for a given application depends on a number of factors and has to be selected based on a cost‐benefit analysis. Depending on their function, settling tanks are classified in two general categories: primary and secondary. The main purpose of the primary settling tanks is to remove suspended solids from the wastewater treatment plant influent. Secondary clarifiers are located downstream of the plant's biological treatment facilities, such as aeration basins or tricking filters, and are used to separate the biomass generated during the secondary treatment process from the treated plant effluent. Key design criteria used for sizing primary settling tanks are surface overflow rate and hydraulic detention time, while secondary settling tanks are usually designed based on surface and solids loading rates. Recommended values for these design criteria according to various design guideline sources are presented in a table format.
Slow Sand Filtration and the Impact of
Schmutzdecke
Authors: Rooklidge Stephen J. 
Published: July 2005

Abstract
The use of sand media to filter drinking water dates to the early nineteenth century; and rural areas are the primary benefactors of slow sand technology due to the passive nature of the treatment process and the availability of large tracts of land necessary for filter construction. The source water flows by gravity through the filter column, and biomass forms at the sand/water interface (schmutzdecke) that provides an effective layer for removing pathogenic microorganisms. Although source water quality is an important design consideration when communities consider this technique as a treatment method, slow sand filtration is one of the oldest drinking water treatment techniques and is still a viable method of biological water treatment best suited for raw water sources low in turbidity and suspended solids.
Synthetic and Natural Organic Removal by Biological Filtration
Authors: Ahmad Rasheed 
Published: July 2005

AbstractThe use of biologically active gravity filters to produce biologically stable water has been recognized in Western Europe for at least two decades. In the United States, biological filtration for drinking water treatment is recently gaining interest because of increased use of ozone as a disinfectant. The increased interest also stems from recent stringent water quality regulations. When ozone is used as a predisinfectant in conventional water treatment, rapid gravity filters become biologically active. Without using ozone, there are a variety of approaches to achieve biological filtration or biological treatment of drinking water. Biological treatment can be achieved by slow sand filtration, bank filtration, ground passage, and granular activated carbon (GAC) contact. Although the approaches differ substantially in process configuration, they all have two common and critically important characteristics. The first characteristic is that all of the processes are of the biofilm type in which bacteria are stably retained in the process by natural attachment to a solid surface, such as sand and carbon. The second characteristic is that the processes select oligotrophic bacteria or those bacteria especially adapted to function when their substrate concentrations are very low.
The State of the Water Industry—2004
Authors: Maxwell Steve 
Published: July 2005

Abstract
The water and wastewater treatment industry continues to be an evolving and often unpredictable business, and the year 2003 did not disappoint. The ongoing corporate consolidation in the industry produced surprises and new directions, whereas the headlong rush toward privatization seemed to falter, or at least slow a bit. Water resource issues and water management controversies continued to climb onto the front pages of the popular media; water quality scares, water rights battles, and water security issues gained significant public exposure. Wide‐ranging debate over how to best fund the vast future capital needs of the water business began to take center stage. The extensive regional droughts of 2002 are still fresh in the minds of many people. And although water stocks outperformed the general stock market this year, there still seem to be no big winners emerging.
Water Security: An Emerging Issue
Authors: Purohit Hemant J. , Devotta Sukumar 
Published: July 2005

Abstract
Identification of the links between rapidly growing populations and shrinking freshwater supplies is the essential first step in making water use sustainable. Various models are proposed for prediction of water usage based on climate data. Even water security has been correlated with food security by modeling (8). Yates (9) presented an integrated assessment model for continental scale runoffs where the limiting data for the spatial and temporal variability of freshwater resources is the constraint. An analysis of Western Europe's and Africa's freshwater runoff, which spans a range of climate variability, was performed at varying levels of spatial aggregation and at both monthly and annual time steps. Model results showed that regional runoff characteristics were lost beyond a data aggregation of 1° × 1° resolution. A macroscale hydrological model, designed to simulate stream flow from climatic inputs over a large geographic domain, has been proposed by Arnell (10). In the case of Hydrological Model of WaterGAP 2 (WGHM), the model tuning has aimed at achieving a good representation of the long‐term average discharges (11). It has a strong positive effect on the performance of all proposed water availability indicators.
Well Head Protection
Authors: Makinde‐Odusola Babalola 
Published: July 2005

AbstractGroundwater, especially karst aquifers (1) or groundwater under the direct influence (2) of surface water, is vulnerable to contamination from possible contaminating activities (PCAs) (3) related to land use. A wellhead protection (WHP) plan (WHPP) essentially includes the integrated proactive management practice(s) that protect the quality of groundwater that is a source of drinking water. WHP is part of an integrated (from source to consumer's tap) multibarrier system to reduce risks to public health from drinking water. WHP fits into the World Health Organization's (WHO's) Water Safety Plan that recommends the use of hazard analysis and critical control points (HACCPs) as a risk management tool in drinking water operations (4). In the United States, many public water systems (PWSs) are required to conduct source water assessment (SWA) (3, 5, 6, 7). For PWSs that source from groundwater, a WHPP can be part of their SWA program (SWAP). A PWS must develop its WHPP in accordance with guidelines established by regulatory agencies (1, 2, 3).
Drinking Water Quality Standards (DWQS)‐UnitedStates
Authors: Makinde‐Odusola Babs A. 
Published: July 2005

AbstractIn 1974, the U.S. Congress, through the Safe Drinking Water Act (SDWA), created the first‐ever mandatory national program to protect consumers from harmful contaminants in drinking water. There have been several amendments to the Act—the most recent in 1996. The SDWA requires the U.S. Environmental Protection Agency (EPA) to set national drinking water quality standards (DWQS). The EPA has set primary and secondary DWQS for chemical, physical, radiological, and microbiological contaminants listed in Tables and. More Americans are now served by water systems without health risk violations since the EPA began tracking violations around 1980.
Evaluation of Microbial Components of Biofouling
Authors: Smith Stuart A. 
Published: July 2005

AbstractDetecting the occurrence of biofouling and assessing its impact involve a range of analytical techniques, including informed observation and inspection of well components, interpretation of hydraulic and water quality testing, and direct analysis of microbial components of biofouling. The latter is the subject of this article.Symptoms: Indirect Analysisclogging (both formation/well and pump/discharge systems).corrosionalteration of water quality in pumped samplesdistinct coating on surfaces visible during inspections, such as borehole television surveys.Such symptoms are indications of biofouling and should trigger analysis to determine the nature of the biofouling.
Seawater Temperature Estimates in Paleoceanography
Authors: Cortese Giuseppe 
Published: July 2005

Abstract
Temperature, together with salinity, determines the density of seawater, and therefore, it strongly influences its circulation and sinking characteristics.
In turn, the important role oceanic circulation and deep‐water formation play in past, present, and future climatic change lend a special significance to the estimate of past seawater temperature.
As the past values of this important climatic variable in the distant, geological past are impossible to measure directly, a variety of indirect methods, so‐called “proxies,” have been developed. These methods are usually based on the fossil faunal/floral composition of sediment core samples, as a close link exists between species occurrences/abundances and environmental variables.
Semiquantitative (e.g., faunal provinces indexes) and quantitative (e.g., transfer functions, neural networks) techniques are therefore applied to reconstruct past sea surface water variables, including temperature.
Additionally, several geochemical methods have been recently developed to estimate past ocean temperatures by measuring chemical elements (Mg/Ca, Sr/Ca) or organic compounds (alkenones), which are either incorporated in the organism shell, or produced during its life cycle.