bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bacteriophages in Engineered Bioreactors
Authors: Islam Md Imdadul , Goel Ramesh 
Published: December 2019

AbstractBacteriophages, viruses that infect bacteria, coexist with their prokaryotic hosts in activated sludge reactors. They are among the most diverse biological entities in aquatic and terrestrial ecosystems, surviving through predation and horizontal gene transfer and have profound effects on microbial ecosystems everywhere. As microbial ecology is an integral part of any environmental biotechnology process, it is important to understand the factors that affect the microbial ecology composition. Little attention has been paid to the diversity of phages in engineered bioreactors, such as in activated sludge processes (ASPs). Phage treatments have the potential to control environmental wastewater process problems including, but not limited to, foaming in activated sludge plants, sludge dewaterability and digestibility; pathogenic bacteria; and to reduce competition between nuisance bacteria and functionally important microbial populations. These problems affect the treatment process and deteriorate the quality of effluent and sludge. Understanding phage–bacterial dynamics is important for successful application of phage therapy to wastewater problems. In this article, we present some important features of bacteriophages and then summarize the current state of knowledge related to the presence of bacteriophages in engineered bioreactors. Finally, we conclude this article with some future recommendations related to the need to study phages in engineered bioreactors.
Microbial Interactions in Anaerobic Wastewater Treatment
Authors: Wang Yongfeng , He Qiang 
Published: December 2019

AbstractAnaerobic treatment technology, represented by anaerobic digestion, is an important microbial process for wastewater treatment. Anaerobic treatment is superior to aerobic processes with reduced energy demand, lower excess sludge production, and the generation of methane as a source of renewable energy. In anaerobic treatment, organic waste is converted into methane and carbon dioxide via four successive steps – hydrolysis, acidogenesis, acetogenesis, and methanogenesis. The interactions between microbial populations have major impacts on the performance of anaerobic treatment processes. The competition between populations ofFirmicutesandBacteroidetesis closely correlated to process stability. Similarly, the competition between two acetoclastic methanogens with distinct kinetics characteristics, i.e.MethanosaetaandMethanosarcina, is linked to changes in the level of acetate as a metabolic intermediate associated with process perturbations. Further, syntrophic interactions between theBacteriaandArchaeaplay central roles in maintaining process balance. Indeed, syntrophic interactions are required for the conversion of diverse intermediates and substrates, including organic acids, alcohols, and aromatics, in anaerobic treatment. The microbial interactions underlying anaerobic treatment are critical to process performance. The availability of new tools, such as high‐throughput sequencing technologies, makes it possible to gain further understanding of population interactions at the microbiome level in order to develop more robust anaerobic treatment processes for broader applications as sustainable alternatives.
Energy Use in Water Distribution Systems: A Life Cycle Perspective
Authors: Karunathilake Hirushie , Prabatha Tharindu , Khan Shahnawaz , Hewage Kasun 
Published: December 2019

Abstract
Water distribution systems (WDSs) serve to deliver water from the source to intended consumers or endpoint applications, with the requisite quality and quantity. While these systems are a critically needed aspect of modern civilizations and their infrastructure, they also consume significant amounts of energy during their life cycle. The environmental impacts related to energy use have received global attention in recent times, with increasing concerns about anthropogenic climate change. Efforts are being made at all levels to reduce energy use in order to achieve the climate action targets set at regional, federal, and global levels. Water pumping to end users causes the highest energy use impacts in a WDS. The flow distances, component sizing and facility locations, flow rates, and other parameters need to be carefully managed in designing water distribution networks to minimize energy use and economic impacts. In attempting to develop more energy efficient WDSs, their energy use and impacts need to be contemplated from a holistic life cycle perspective.
Hofmeister Effects
Authors: Parsons Drew F. , Boström Mathias , Kunz Werner , Ninham Barry W. 
Published: December 2019

Abstract

Hofmeister effects, also known as specific ion effects, are variations in interactions between particles and surfaces or other particles in salt solutions that depend on the specific identity of the ions comprising the salt. Na
+
is the dominant cation in physiological fluids, Li
+
is used to treat bipolar disorder, K
+
is used in lethal injections. The differences matter, and yet these ions are identical if considered solely as simple point charges. Hofmeister effects are ubiquitous, observed in protein aggregation, surface tension, bubble coalescence, pH. The origin of specific ion effects can be understood as a consequence of electron structure, both in ion size and in polarizability of the electron cloud. Not only the intrinsic size of the ion but also recent theoretical developments suggest the formation of the cavity in the solvent, in which the ion resides, plays a key role in determining these effects, alongside ionic van der Waals interactions driven by ion polarisability.
Canopy‐Forming Ecosystem Engineers in Aquatic Ecosystems
Authors: Hendriks Iris E. , van Duren Luca A. , Ackerman Josef D. 
Published: December 2019

AbstractAquatic vegetation can form dense beds, spanning a range of scales, from forestlike canopies of tens of meters high created by giant kelps to small meter‐ or decimeter‐scale canopies of seaweeds and aquatic plants. These canopies interact with the flowing water in the overlying water column and have a profound effect on biogeochemical, biological, and ecological processes. In near‐bottom environments these organisms contribute substantially to bottom roughness as they form flexible canopies, which modify hydrodynamic properties in the near bed region with concomitant effects on sediment and ecological processes. In this article, we describe the environment aquatic macrophytes live in and then consider the fundamental biological and ecological processes including mass transport of dissolved material, such as nutrients, carbon, and oxygen, and their uptake by the vegetation and transport of particulate matter, such as sediment and organic matter, which has implications for carbon sequestration and sediment accretion.These processes, aptly called ecosystem services, are important for human societies and attract the interest of researchers who will add to our understanding of the fundamental processes that are due to the interaction of fluid dynamics and macrophytes in a changing climate. This will facilitate transformational thinking and ultimately innovative solutions required for the future of humanity.
Nonlinear Wave Interactions over Coastal Muds
Authors: Tahvildari Navid , Sharifineyestani Elham 
Published: December 2019

AbstractMany coasts around the world are fully or partially muddy. Surface waves sustain attenuation and modulation over mud, and bottom mud is fluidized and suspended in response to surface forcing. Surface wave–mud interaction has been studied numerically, theoretically, and in the field. In this study, we outline some recent theoretical and numerical work on the subject. Particularly, we discuss phase‐resolved numerical simulation of surface wave evolution over viscoelastic mud in the presence of currents and highlight the significance of mud elasticity on the process. Ignoring mud elasticity, which is the case in operational models, questions their application to a wide range of wave conditions where mud exhibits solid‐like behavior. We also discuss analytical models, developed using perturbation theory, to study generation of interfacial waves by a surface wave in a two‐fluid system as a feedback from the mud layer to surface forcing. Comparison between a second‐ and third‐order model shows that while the second‐order model is sufficient to study the generation process, it substantially overestimates long‐term amplitude of interface oscillations. Impacts of important parameters on dynamics of interfacial wave generation, namely relative thickness of mud layer, ratio of density and viscosity of mud to water, and surface wave properties are investigated.
Methane in Groundwater: Pathways
Authors: Martini Anna , Osborn Stephen , McIntosh Jennifer 
Published: December 2019

Abstract

Groundwater can contain measurable quantities of methane associated with
in situ
processes of methanogenesis and desorption from geologic materials, and also from external migration from deeper gas‐bearing units. It may also contain “fugitive gas” due to leakage from exploration and production of hydrocarbons or from the microbial breakdown of organic contaminants introduced to the aquifer. More recently, natural gas production via high volume hydraulic fracturing of tight formations has been implicated as a route for both methane and other fluids to enter groundwater resources. While distinguishing the source of the gas is often critical, secondary processes such as mixing and aerobic and anaerobic oxidation make these identifications difficult. Important to these determinations is an understanding of the hydrology, geology, and history of development in the watershed, coupled with detailed geochemical and isotopic analysis.
Low‐Flow Groundwater Purging and Sampling
Authors: Vance David B. , Jacobs James A. 
Published: December 2019

Abstract
Low‐flow groundwater sampling was developed in the 1990s as a way to obtain accurate, representative, and reproducible groundwater samples in a manner which generated less sampling‐derived liquids requiring disposal. Groundwater monitor wells are installed primarily as tools to measure the dissolved concentrations of contaminants in groundwater in and around facilities where the release of contaminants has occurred or where the potential exists for such a release. Although they are widely used, there are still questions about how best to collect samples from groundwater monitoring wells in such a way as to generate representative results. Installation of a well always results in some disturbance of the local environment around the well. Moreover, water in a well can become stagnant and often does not reflect the surrounding groundwater conditions. Traditional methods of purging can be problematic. Thus, low flow groundwater purging is an important method to be used prior to sampling. This article discusses methods of low flow purging for groundwater monitoring wells
Microbes and Inorganic Colloids in Particulate Transport in Groundwater
Authors: Vance David B. , Jacobs James A. 
Published: December 2019

Abstract

Enhanced bioremediation via bioaugmentation requires understanding of groundwater flow of both colloids and microbes. Groundwater microbes not only include primarily bacteria but also may include archaea, fungi, protists, viruses, and other microscopic organisms. Bacteria, the largest portion by mass or population of groundwater microbes, are single‐celled organisms that lack a true nucleus and normally have a cell wall. There may be from 100 million to 1 billion bacteria per gram of dry soil in the shallow soil near plant roots. There may be as many as 10–100 million bacteria per gram in groundwater, depending on depth, nutrients, carbon sources, and redox conditions. Evaluation of mass transport of entrained material in groundwater flow systems is typically focused on two primary areas, dissolved organic or inorganic species, and flowing free phase liquids. However, although generally not as dominant overall, the movement of small particles in groundwater can cause problems at the low concentrations required by regulatory limits. In addition, the proponents of
in situ
bioaugmentation, through injection of bacteria, must rely on successful particulate mass transport through the saturated soil matrix.
Natural Attenuation and Enhanced Bioremediation of Petroleum Hydrocarbons Geochemical Factors in Groundwater Remediation
Authors: Jacobs James A. , Vance David B. 
Published: December 2019

Abstract

In situ
monitored natural attenuation (MNA) and enhanced bioremediation of petroleum hydrocarbons released into the environment are affected by a variety of limiting factors, including the availability of a terminal electron acceptor (TEA), macronutrients (nitrogen and phosphate), as well as an energy source (carbon). The TEA for aerobic degradation is limited to oxygen. For anaerobic degradation, TEA processes include denitrification using nitrate (NO
3
−
), manganese reduction using manganese dioxide (MnO
2
), iron reduction using bioavailable iron that includes the hydroxide form (Fe(OH)
3
), sulfate reduction using the sulfate ion (SO
4
2−
), and methanogenesis using carbon dioxide (CO
2
). Of this list, dissolved oxygen is usually the limiting factor. Other factors that limit or inhibit microbial growth include toxic concentrations of naturally occurring or anthropogenic metals or other contaminants.

Macronutrients are measured in the laboratory as nitrogen in the form of ammonia or nitrate and orthophosphate. Nutrients, although important, are not as critical as depletion of the TEA. The energy source is the carbon in the hydrocarbons or chlorinated solvents that act as food for the microbes.
MNA occurs when these processes are believed to be occurring on their own without additives. Natural attenuation frequently starts on many hydrocarbon sites, but the aerobic degradation process frequently stops or slows down considerably because of the limiting factors of oxygen and nutrient depletion.
Benzene in Groundwater: Chemical Behavior and Treatment
Authors: Jacobs James A. 
Published: December 2019

Abstract

Benzene (C
6
H
6
) is a clear, colorless, highly flammable aromatic hydrocarbon liquid. As an important ingredient for making plastics, rubber, resins, and synthetic fabrics like nylon and polyester, benzene is one of the most commonly used industrial chemicals in the world. It is also used as a solvent in printing, paints, and dry cleaning. It is also a major component of gasoline. The wide ranging industrial applications of benzene make it widely distributed, particularly in the case of petroleum products, of which it is a primary constituent. Benzene is highly toxic to humans and the environment. Because of its severe toxic effects, both in the short and long term, benzene use has been under strict regulations for many years. Nonetheless, widespread contamination of benzene has occurred in the environment, and, therefore, significant regulatory efforts in the United States and other nations are being enacted to limit or eliminate potential impacts.
Organic Compounds Present at Minute Concentrations in the Hydrologic System
Authors: Jacobs James A. 
Published: December 2019

Abstract

Laboratory analytical methods have continuously improved during the past few decades with much lower detection levels enabling some interesting studies of human impact on the condition of the hydrologic system. Certain organic contaminants are present at extremely low concentrations in surface and groundwaters throughout the nation, even in remote wilderness areas. This article focuses on some organic contaminants frequently found at extremely low levels. Such compounds include organic wastewater contaminants (OWCs) such as steroids, nonprescription drugs, insect repellent, detergent metabolites, disinfectants, plasticizers, and fire retardants. The gasoline additive methyl
tert
‐butyl ether (M
t
BE) and certain chlorinated solvents can also be found at very low levels in some public supply wells. This article provides a brief overview of some key organic contaminants that occur at very low levels in waters in the United States and many other parts of the world. Their occurrence and distribution are starting to be better understood as more waters are sampled and surveyed using low‐detection‐limit methods of organic analysis.
Nitrate in Groundwater: Chemical Behavior and Treatment
Authors: Jacobs James A. 
Published: December 2019

AbstractNitrate (NO3) is a naturally occurring substance, which is an essential nutrient for the growth of plants. Nitrates from animal manure such as cattle and oxen have long been used as a natural fertilizer in fields. Early commercial sources of nitrates were guano, the accumulated excrement of seabirds and bats, rich in nitrogen, phosphate, and potassium. With the development of the Haber–Bosch process, an industrial‐scale manufacturing of nitrate fertilizers was possible in 1910. This breakthrough in chemistry has allowed farmers the availability of low‐cost artificial nitrate fertilizers for over the past 100 years. Excessive nitrate fertilizer use combined with runoff from fertilized farmer fields, gardens, golf courses, lawns, and other facilities, has, over time, allowed for nitrate impacts to ground and surface waters. Today, nitrates are sourced from nitrate fertilizers, the storage or use of animal manure, leaky septic systems, leaky sanitary sewer pipelines, and improper disposal of treated wastewater containing high nitrate levels. Through storm runoff and leaching processes, nitrates have become dissolved in stormwater runoff or infiltration waters. These sources of dissolved nitrates have created significant impacts on worldwide surface water and groundwater resources. The impacts may vary with the season, where nitrate‐rich stormwater is commonly associated with spring storms and runoff. The excess nutrients in rivers, lakes, bays, and marine waters create ecological dead zones. Dead zones exist where dissolved oxygen concentration are low and fish and other aquatic life cannot survive and suffocate. Dead zones are biological desserts where healthy and diverse marine life are absent and only jellyfish and organisms capable of surviving hypoxic marine conditions can survive.Nitrate is an integral part of the nitrogen cycle, especially at the microbial level. A microbial process called nitrification is performed by nitrifying bacteria. Although ammonia can be used by some plants as an essential nutrient, most nitrogen taken up by plants is processed by nitrifying bacteria to convert ammonium (NH4+) into nitrite (NO2–), and then into nitrate (NO3–) where it can be used by the plant. At an even smaller scale, at the molecular level, nitrate is used in the respiratory electron transport chain in the absence of oxygen. For subsurface remediation in the absence of oxygen, anaerobic microbes in the groundwater can use available nitrate for cellular respiration, making nitrate one of four alternate terminal electron acceptors.
Uranium in Groundwater: Chemical Behavior and Treatment
Authors: Jacobs James A. 
Published: December 2019

Abstract
Uranium can occur naturally in groundwater or it can be present as a result of processing for nuclear reactors, nuclear weapons, and other uses. Uranium can occur in nature in four oxidation states, and environmental redox conditions can affect uranium fate and transport in groundwater. Although uranium is radioactive and can cause cancer, its primary toxic effect when consumed in water is that of a heavy metal. This article outlines the occurrence, distribution, redox chemistry, and fate and transport of uranium in groundwater. The article also introduces a variety of methods for uranium groundwater remediation.
Arsenic in Groundwater: Chemical Behavior and Treatment
Authors: Vance David B. , Jacobs James A. 
Published: December 2019

AbstractArsenic (As) is a naturally occurring metalloid element with atomic number 33. Although widely distributed in the Earth's crust, Arsenic is only the 52nd element in terms of crustal abundance. Because arsenic is toxic and can cause various forms of cancer, it must be removed from drinking water. A variety of different removal treatments and technologies are discussed in this article.
Groundwater Remediation and Horizontal Wells
Authors: Jacobs James A. , Vance David B. 
Published: December 2019

Abstract
Horizontal wells have been used in an increasing number of groundwater remediation projects. In addition to chemical and biological reactive barriers, horizontal borings can be used for groundwater extraction and control, air sparging, bioremediation, groundwater injection, for vadose zone soil vapor extraction or bioventing systems, and free product recovery. This article provides an introduction to horizontal well technology and its use in groundwater remediation.
Groundwater Remediation by Injection
Authors: Vance David B. , Jacobs James A. 
Published: December 2019

Abstract

With few exceptions, groundwater remediation requires either an
in situ
injection of reactive chemicals or groundwater recovery, treatment, and disposal. The reinjection of treated water or the placement of chemicals in the subsurface used to treat contaminants can cause unintended subsurface geochemical conditions that may create new contamination issues or impact
in situ
transport properties. This article discusses methods for preventing subsurface challenges related to water injection during groundwater remediation or water disposal.
Remediation of Metals in Groundwater
Authors: Jacobs James A. , Vance David B. 
Published: December 2019

Abstract
Many ground waters and soils around the world are plagued by metals contamination, which can pose substantial ecosystem and human health risks. Given the widespread problem and the paucity of innovative approaches to remediation, it is clear that metal contamination represents a serious environmental concern as well as a significant market opportunity for environmental service companies. This article provides some general background on metals chemistry and insight into potential groundwater remediation strategies.
Vibrio Bacteria in Aquatic Ecosystems: Effects of Climate Change on Antibiotic Resistance
Authors: Scott Cecile Hart , Horton Cassie , Brett Catherine , Palmer Emily , Pipes Shannon , Tufford Dan , Sandifer Paul A. , DeLorenzo Marie , Pennington Paul L. , Porter Dwayne E. , Ek Christina , Norman Sean , Scott Geoffrey I. 
Published: December 2019

AbstractWater is essential for all life as we know it, but it can also be the source of dangerous and even fatal diseases, such as those associated with certain Vibrio bacteria. This article focuses on several Vibrio bacteria that are known to cause severe and potentially fatal illnesses, the most high profile of which is cholera. The article begins by discussing how Dr. John Snow first recognized that cholera was a waterborne disease, using data he collected in Victorian Age London. Three prominent disease‐causing Vibrio species:V. cholerae,V. parahaemolyticus, andV. vulnificusare then discussed in some detail in terms of how they cause illness, primarily from seafood consumption, wound infections, and waterborne illness as well as the role climate change may play in terms of impacting the rapid spread of Vibrio illness observed globally the past 25 years. Today environmental scientists and epidemiologist are faced with the same dilemma with climate change and Vibrio bacteria that Sir John Snow was faced with cholera and urbanization in the nineteenth century. Since climate change may be affecting the occurrence, distribution, and even the virulence of these pathogenic organisms, we conclude by discussing how interdisciplinary teams of scientists are developing complex epidemiological tools and forecast models to better inform the public and prevent future Vibrio‐associated illnesses just as Sir John Snow did with cholera.