bluuebunny/crossref_metadata_2025 huggingface dataset:
Graphene Coatings for Microbial Corrosion Applications
Authors: Chilkoor Govinda , Shrestha Namita , Karanam Sushma Priyanka , Upadhyayula Venkata K.K. , Gadhamshetty Venkataramana
Published: December 2019

Protective coatings are widely used to control microbially induced corrosion (MIC) of ferrous and nonferrous metals and maintain their aesthetic appeal and structural integrity. The use of ultrathin graphene films as protective coatings in biological environments is discussed in this article. The way the atomic scale surficial features of graphene coatings influence adherence, colonization, and biofilm growth aspects of bacteria responsible for MIC of underlying metals is discussed. A critical review of the literature is carried out to evaluate the microbial corrosion resistance of pristine graphene and its functionalized forms. The article is concluded with a discussion on environmental impacts, technical challenges and potential solutions, and commercialization prospects of graphene coatings.
Water Conservation for Sustainable Agriculture
Authors: Shen1 Yanjun , Pei2 Hongwei
Published: December 2019

Agriculture not only consumes 70% of global freshwater and 90% of global groundwater but also causes a lot of environmental problems, such as drying up of rivers, groundwater depletion and pollution. Thus, water conservation is considered a necessary requirement if we are to feed the booming global population by supporting sustainable agriculture. Generally, increasing water supply (e.g. interbasin water transfer, artificial precipitation) and enhancing water use efficiency via water‐saving technologies (e.g. dripping irrigation, mulching, deficit irrigation, and water‐saving cultivars) are the main ways to solve water resources shortage in agriculture. In practice, water use efficiency in different scales is measured to help people to realize the importance of the process of water consumption and to enhance water productivity. Water transfer and other human actions also aim to sustain the water demand of human society. However, overuse of water resources is still threatening human lives in most countries globally, and we need to employ water‐saving technologies, increase reuse of water continually, and also mind the risks from agricultural intensification (irrigation and fertilization) and climate change on food production.
Nuclear Wastes in the United States
Authors: King1 Judy Y. , Hylko2 James M.
Published: December 2019

The nuclear fuel cycle in the United States began during World War II and was associated with the Manhattan Project. The presence of nuclear wastes has been under review and control by the federal government since that era.

The techniques for treating liquid wastes are well established and effective to meet the current government standards. The future treatment and handling of waste residuals from the nuclear industry elements (mining, beneficiation, use and disposal) require additional study and, potentially, different technical solutions to meet health and exposure standards.
Hydrology and Climate Change in Pacific and Similar Regions: Insights from Hawaii
Authors: Leta Olkeba Tolessa , El‐Kadi Aly I.
Published: December 2019

Population growth in Hawaii is causing major stress on available water resources. In addition, it is anticipated that climate change will lead to challenges concerning freshwater availability and negatively affect related natural habitats. This article reviews the consequences of changing rainfall, temperature, and solar radiation on groundwater resources. It also addresses the effect of sea level rise on the inundation of the coastal zone areas. Studies have shown that Hawaii is generally expected to face an overall decline in rainfall amount, increase in temperature, with a higher rate at elevated altitudes, and amplified rate of sea level rise. Such changes are projected to threaten groundwater availability and sustainability, cause recurrent hydrological droughts, and groundwater inundation and flooding of coastal zones. Nearshore problems can include damages to coastal infrastructures, salt‐water intrusion, and reduction in groundwater quality, and loss of aquatic habitats. Further, these impacts are anticipated to be amplified toward the end of this century. Owing to limited groundwater resource over the Islands, water use restrictions are most probably to happen with expected increases in agricultural water and other water‐use demands. Therefore, utilizing adaptation measures to climate change for Hawaii and similar Islands are of critical importance.
Using Citizen Science to Raise Public Awareness and Engagement with Water Issues
Authors: Araya Yoseph
Published: December 2019

The world faces increasing freshwater supply challenges, fueled partly by rising demand as well as mismanagement of existing resources. This necessitates an aware and engaged public as well as sound water resource management that is supported by data‐driven scientific knowledge. Often the public lacks sufficient awareness to participate in resource management; and too often scientists and decision‐makers struggle to obtain sufficient good quality data (across time and space scales) to effect change. Citizen science offers a powerful tool to tackle both these challenges by providing efficient and effective ways to obtain useful data while educating citizens about water issues. This article uses examples to describe the role of citizen science, the opportunities available for engagement and identifies criteria for success.
European Marine Biodiversity Observatory Systems
Authors: Hummel Christiaan , Hummel Herman , van Avesaath Pim , Magni Paolo
Published: December 2019

This article provides an overview of European Marine Biodiversity Observatory Systems. It explains why more attention should be focused on marine biodiversity and raises concern about the understudied marine realm. It builds on a historical perspective of the creation of networks of marine stations, as well as the need of harmonization among them. Finally, a few examples of successful projects and results obtained are given, followed by concluding remarks from the current situation to a future perspective.
Kinetics of Halogenated Disinfection By‐Products Formation in Chlorinated Seawater
Authors: Elsaid Khaled , Batchelor Bill , Abdel‐Wahab Ahmed
Published: December 2019

The use of seawater as a source for potable water supply after desalination, and in once‐through industrial cooling is a common practice in many parts of the world that have limited fresh‐water resources. A disinfectant (commonly chlorine) is added to the seawater to control biofouling in desalination or cooling systems. The added chlorine reacts with bromide and other compounds present in seawater to produce a wide range of chemical oxidants. Regrettably, reactions between the residual oxidants and natural organic matter present in seawater lead to the formation of halogenated organic compounds that have detrimental effects on human health and the environment. Of particular note is the fact that brominated forms of disinfectants are more effective in producing halogenated organic by‐products than chlorinated forms. In this article, the kinetics of residual oxidants decay and formation of halogenated disinfection by‐products (DBPs) in seawater is discussed and explained in detail. A kinetic model is developed, which includes rate constants for all base reactions and stoichiometric coefficients for all halogenated (DBPs) formed by these base reactions. The model is calibrated using experimental results to obtain the different kinetic rate coefficients.
Retardation
Authors: Holzbecher Ekkehard
Published: December 2019

The transport of chemical or other type species in a flow field may be retarded in relation to that of mean fluid particles. Measurements may indicate that the species in question has a lower velocity than the fluid. Such retardation is observed in natural and artificial systems of various types. In the different environments, different processes are responsible for the observed phenomenon. They all have in common that for a certain time period, a part of the substances are not participating in the transport, but are stagnant or almost stagnant. The mathematical description is outlined, which is common for various cases and that leads to the introduction of a retardation factor as a measure for the effect. It is shown that retardation cannot be understood in a strict sense as a simple prolongation of the timescale. Finally, also thermal retardation is covered analogously to solute retardation.
Potential Flow
Authors: Holzbecher Ekkehard
Published: December 2019

The concept of potential flow is derived from a classical mathematical theory that can be formulated in terms of complex analysis (in 2D). The basic definitions of this classical theory are presented, followed by the presentation of elemental potential flows. The powerful technique of superposition allows the construction of solutions with specific properties, concerning sinks, sources, rotations, boundary conditions, etc. The technique of mapping enables the construction of solutions in irregular domains from solutions in simpler geometries. The field of groundwater and porous media flow is taken as an example for a brief demonstration of how potential flow solutions are used in applied problems.
Wind Generation of Waves
Authors: Hristov Tihomir
Published: December 2019

The mechanism responsible for the generation of ocean waves by wind is described. The physical analysis here develops from first principles and requires only the well‐verified premise of small‐slope waves, ensured by the phenomenon of wave breaking. The wind generated waves occur from the coherent interaction between two distinct and random fluid‐mechanical fields – the turbulent atmospheric flow and the compliant ocean surface. The dynamic and statistical patterns of the wave‐coherent air motion as well as the dynamic significance of the critical height in the air flow are outlined. The phase discontinuity of the wave‐coherent air flow at the critical height is specifically discussed, as it is among the testable predictions of the theory. Experimental evidence in support of wind wave generation through wave‐coherent flow with a critical layer is presented.
Wastewater Treatment: Mathematical Modeling
Authors: Dudley Jeremy
Published: December 2019

In 1985, mathematical modeling in wastewater was described as having no real value and that the use of existing rules of thumb and loading rates was sufficient to design treatment systems. Two years later, the release of the IWA Activated Sludge Model No. 1 kick‐started the wide use of mathematical modeling for activated sludge systems. Since then modeling has seen wider use, for design and operation and covering more process units. This article provides a summary of the more commonly available models. There is a brief summary of literature references for solving differential equations, and for applying the unit process models as part of an integrated flowsheet for whole treatment trains.
Phosphorus and the Baltic Sea: Sustainable Management
Authors: Berthold Maximilian , Nausch Günther , von Weber Mario , Koch Stefan , Kahle Petra , Lennartz Bernd , Tränckner Jens , Buczko Uwe , Tonn Claudia , Ekardt Felix , Bathmann Ulrich
Published: December 2019

Worldwide, many aquatic systems are under anthropogenic induced pressure by elevated nutrient inputs. In particular, increased nitrogen and phosphorus usage have led to human‐induced eutrophication (including cyanobacterial blooms and hypoxia) of all kinds of water bodies. Associated pressures need to be described, and diminished, in order to reach a sustainable human usage of ecosystems. The Baltic Sea is a model system, as it is prone to Global Change, and is strongly influenced by human actions and shows recurrent cyanobacterial blooms and hypoxia. There have already been several actions to ameliorate these problems, e.g. by reducing the inflow of phosphorus. However, even the strongest possible reductions are currently not enough to restore the Baltic Sea. Coastal water bodies are still highly eutrophic, and the catchment area is affected by permanent runoff‐events from adjacent land. Furthermore, new approaches are needed to improve the efficiency of water treatment plants. On the other side, legislation is sometimes inefficient on a local scale. Such problems can only be solved in multidisciplinary approaches that include environmental, engineering and social sciences. Here, we present an overview of recent research with emphasis on phosphorus and its flows and controls into the Baltic Sea from the German catchment area.

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Undergraduate Geoscience Education in Environmental and Water Sciences
Authors: Arthurs Leilani A.
Published: December 2019

The landscape of undergraduate geoscience education in the United States is changing, and existing research supports a shift in educational practices away from traditional lecture toward more active learning. Translating the general best practice of active learning into domain‐specific instruction (e.g. environmental and water sciences domains) remains a challenge. Findings from emerging areas of undergraduate geoscience education research and geocognition research can help to meet this challenge. In the meantime, instructors of undergraduate environmental and water sciences courses can access several repositories for class activities and assessments. These include the
Journal for Geoscience Education
,
Digital Library for Earth System Education
,
Science Education Resource Center
,
On the Cutting Edge: Strong Undergraduate Geoscience Teaching
, and
Teaching about Earth for a Sustainable Future
. These resources can help advance individual geoscience instructor efforts to transform their courses and, thereby, transform the landscape of undergraduate geoscience education.
Water Well Drilling Methods
Authors: Jacobs James A.
Published: December 2019

Water well installation, for domestic or public water supply purposes, groundwater monitoring projects or for irrigation involves a variety of drilling techniques, depending on subsurface conditions, groundwater depth, access, and other factors. The three most common drilling methods for potable water supply wells are rotary drilling, auger drilling, and cable tool drilling. More recently sonic drilling has been used in certain for potable water well construction. The main challenge in drilling is to drive the drill string to the target depth while removing the drill cuttings and maintaining borehole wall integrity. Each drilling location has site‐specific surface and subsurface conditions, selecting the optimal drilling method is critical to installing a successful well. Drilling method selection relates to a variety of factors, including rig and crew availability, site accessibility, time and cost of project, sediment type (consolidated rock or unconsolidated soils), special drilling problems (unconsolidated sediments and soils, pressurized saturated sands, lost circulation zones, cobbles, and boulders), soil/rock sample type desired (undisturbed vs. disturbed), and sample integrity.

For contaminant studies and environmental projects, monitoring and remediation water wells (and vapor wells) are installed, which frequently relate to chemical spillage on or near the surface. The most common drilling method for installing shallow monitoring and remediation wells is hollow stem auger drilling which works well in soil and unconsolidated sediments, and soft rocks. Hard rock drilling required for environmental projects have used air rotary or cable tool drilling rigs, and to a lesser degree, mud rotary drilling rigs. Soil/rock, soil vapor, and groundwater collection and integrity are critical for environmental projects where depth discrete sampling is common as well as vadose zone sampling. The vadose zone, also called the unsaturated zone, includes the zone immediately above the water table to the surface. The lower vadose zone includes the capillary fringe, the zone where water is drawn upward by capillary force. The water table is the top of the saturated or phreatic zone within the aquifer. Other drilling methods are used for contaminant studies, including direct push and sonic drilling.
Cobalt in Groundwater: Chemical Behavior and Treatment
Authors: Jacobs James A.
Published: December 2019

Cobalt occurs naturally in ores with oxygen as cobalt oxide and with other elements and has characteristics similar to the properties associated with iron and nickel. Cobalt has an atomic number of 27 and there is only one stable isotope of cobalt, having an atomic mass number of 59. There are many unstable or radioactive isotopes of Cobalt, two of which are important commercially: cobalt‐60 (Co‐60 or
60
Co) and cobalt‐57 (Co‐57 or
57
Co). All isotopes of cobalt behave the same chemically. Cobalt enters the environment through both natural processes and anthropogenic activities. The metal has been known to be contained within windblown dust, seawater spray, forest fires, and volcanic eruptions. When deposited as part of particulate, the cobalt can be leached by rainwater taking the cobalt into the vadose zone and possibly deeper into shallow groundwater. Soil near cobalt ore deposits, phosphate rocks or other ore smelting facilities, may contain high levels of cobalt as well as soils and dust generated from highway and airport traffic and other industrial activities creating air pollution. Cobalt has also been known to be released into the air from a variety of common industrial uses or processes, including coal‐fired power plants, mining, and processing of cobalt ores, production and use of cobalt alloys and chemicals, vehicular exhaust and incinerators Remediation of cobalt is similar to other metals where cobalt in a reduced state as cobalt sulfide precipitates out of groundwater in the presence of a strong reducing agent such as sodium metabisulfite, calcium polysulfide or ferrous sulfate. Permeable reactive barriers with zero‐valent iron (ZVI) and other amendments have also been used to create reducing conditions for metal precipitation.
Soil and Groundwater Sampling Methods
Authors: Jacobs James A.
Published: December 2019

Groundwater assessment for environmental projects involves significant soil sampling to evaluate hydrologic and lithologic conditions. Soil samples in environmental investigations are typically collected at a minimum of 1–2 m and at changes of lithology or obvious signs of contamination, based on soil staining or discoloration of the soil or in the case of volatile organic compounds, organic vapor readings. Continuous coring is recommended for a minimum of at least one soil boring per site to characterize the subsurface adequately. Soil samples collected in the vadose zone above the water table are in the unsaturated zone. Groundwater is moving generally vertically, and some horizontal movement is caused by rootlets, faults, impermeable layers, or other conduits. Soil samples collected within the capillary fringe or below the groundwater table are in the saturated zone.

The capillary fringe moves up and down with seasonal variations of the groundwater table. Petroleum hydrocarbons move vertically from the source, such as an underground storage tank, through the vadose zone. As the hydrocarbons move vertically through the lithologic section, in general, the finer grained the soil, the greater the lateral spreading of the contaminant. The capillary fringe, within the saturated zone, is the zone immediately above the water table, where water is drawn upward by capillary attraction. Owing to irregularities in pore sizes among the grains of sediment, the capillary water does not rise to an even height above the water table but rather forms an irregular capillary fringe. The capillary fringe is higher in fine‐grained soils such as a fine silt than in coarse‐grained soil such as a gravel due to greater tensions created by the smaller pore openings. The capillary fringe can be the zone of direct evaporation of groundwater if the water table is close enough to the surface. This article is an updated version of an earlier article from 2005.
Watershed Nitrogen Budgets
Authors: Fisher Thomas R. , Fox Rebecca J. , Knee Karen L. , Jordan Thomas E.
Published: December 2019

Nitrogen (N) limits primary production in many terrestrial and aquatic systems, a paradox in a world with 78% N2in the atmosphere. Nitrogen has nine valence states ranging from reduced (−3, NH3, amino groups) to oxidized (+5, NO3−), creating opportunities for energy‐yielding microbial transformations of N along redox gradients. Anthropogenic N additions increase plant production and food supplies on land, but simultaneously result in contaminated drinking water, algal blooms, and hypoxia in adjacent waters. Management of these problems is often informed by N flux measurements and budgets. However, in watershed N budgets, measured N inputs typically exceed measured stream output, leading to the conundrum of “missing N.” The missing N is either stored internally within watersheds or lost to the atmosphere as N gases (NH3, N2, N2O, NO). Measurements of both N storage and N gas fluxes have accounted for the missing N in a few cases, but there are few examples of complete N budgets because measurements of the spatially/temporally heterogeneous N pools and N gas fluxes are difficult at the watershed scale. Therefore, investigating watershed N budgets remains a fruitful area for future research to control the deleterious effects of anthropogenic N in aquatic systems.
Xenobiotic Chemicals: Emerging Contaminants and Recalcitrant Compounds in Groundwater
Authors: Jacobs James A. , Mohr Thomas K.G.
Published: December 2019

Xenobiotic contaminants released to soil and groundwater are classified as recalcitrant when they are minimally degraded by common biodegradation and abiotic pathways, and as emerging contaminants when the contaminants meet several criteria, such as (i) potentially harmful to human health, (ii) newly identified due to advances in laboratory analytical capabilities or general awareness, (iii) poorly removed by existing treatment technologies.

In situ
microbial colonies have evolved over time to degrade naturally occurring compounds by exuding enzymes and using various available compounds for either a terminal electron acceptor or as a food source. Xenobiotic chemicals (anthropogenic organic compounds and their reaction products) have chemical characteristics and bond structures which are less susceptible to break down under normal subsurface biogeochemical conditions. Therefore, attenuation of xenobiotic compounds from biodegradation by indigenous soil microbes generally does not occur. Although the source for xenobiotic chemicals relates to synthetic production, the compounds which become emerging contaminants or recalcitrant compounds can originate from a range of uses and activities, from a stabilizing chemical added to an industrial solvent, a reaction product from an industrial process, or a residual waste mixed in and sold as part of a commercial industrial chemical product. More emerging contaminants have been identified in recent years due to advances in laboratory chemical analytical methods, improved understanding of the composition of waste mixtures, and improved monitoring and sampling.
Organic Compounds in Water and Organic Sorption to Minerals
Authors: Maurice Patricia A.
Published: December 2019

Natural organic matter is ubiquitous in aquatic environments and can affect water pH and color. Man‐made organic contaminants are also widespread, ranging from pesticides and herbicides to petroleum products and even pharmaceuticals. This article provides brief background material on aqueous organic chemistry followed by discussion of several different groups of organic compounds, including comments on their sorption to minerals.
Porosity and Permeability
Authors: Maurice Patricia A.
Published: December 2019

Porosity and permeability, two of the most important factors controlling storage and movement of fluids in rocks, soils, and sediments, are briefly discussed here. This material is presented as background for other articles on various topics of soil and groundwater hydrology and geochemistry.
MtBE: Environmental Impacts
Authors: Jacobs James A.
Published: December 2019

Methyl tertiary‐butyl ether (MtBE) is a synthetic compound that was developed as a solution to the problem of air pollution from vehicle emissions. MtBE was originally added to gasoline as a fuel oxygenate in approximately 1979 to reduce air emissions and make the fuel burn cleaner, allowing more complete combustion in internal combustion engines. The concept was to improve air quality by producing fuels that were more readily oxidized and decrease the resulting tropospheric ozone production. In the late 1980s, the U.S. EPA supported the use of fuel oxygenates in reformulated gasoline to achieve air quality goals. Later, between 2000 and 2007, 23 states instituted a partial or complete ban on MtBE. The product bans combined with numerous lawsuits and policy changes effectively destroyed the domestic MtBE market. Now, decades after the introduction of MtBE into the nation's gasoline supply, it is easy to see where the physical and chemical characteristics of MtBE, the limitations of historic storage container designs and the lack of a life‐cycle analysis led to the predictable unintended consequence of MtBE water supply impacts. In 2017, Gulf Coast petroleum refineries are still exporting MtBE as a gasoline additive to other countries.
Sorption and Transport in Porous Media: The Distribution Coefficient

K
d

Approach
Authors: Maurice Patricia A.
Published: December 2019

Sorption, or the uptake of a molecule or ion onto a solid surface such as a mineral or a bacterium, can play an important role in determining the fate and transport of contaminants in subsurface environments. One simple approach that has been widely used to incorporate sorption to the surfaces of porous media into hydrologic transport models is the partition or distribution coefficient, referred to as the linear
K
d
. While the
K
d
approach is not robust and has many limitations, it has been widely used because of its ease of incorporation in transport models. The
K
d
approach is briefly outlined, herein, along with discussion of some of its applications and strengths and weaknesses. While this approach can be problematic, especially when applied to metals, it has been so widely used that it is worthy of discussion.
Water, Life, and the Critical Zone
Authors: Maurice Patricia A.
Published: December 2019

All life as we know it requires the presence of liquid water. This article briefly discusses how and why water is essential for life. Next, the hydrologic cycle, whereby water is moved amongst reservoirs through flow paths, is introduced, along with some key observations about water quality. Finally, the concept of the “
critical zone
” is introduced as the heterogeneous, near‐surface Earth environment where the hydrosphere, the biosphere, the geosphere, and the atmosphere interact with one another and with the human sphere in a complex manner that is of critical importance to life on Earth. Although the term “critical zone” often is used in a manner that specifically excludes coastlines and large bodies of water, it is certainly true that lakes, oceans and coastal regions represent crucial ecosystems and support human societies and economies.
Groundwater and Soil Remediation Using Fenton's Chemistry
Authors: Jacobs James A.
Published: December 2019

Hydrogen peroxide, an
in situ
chemical oxidizer in the form of Fenton's Chemistry, can rapidly treat wastewaters, sludges, and contaminated soils and groundwater. The effect of the Fenton's Chemistry is organic contaminant destruction, toxicity reduction, and biodegradability improvement. In addition, removal of biological oxygen demand (BOD), chemical oxygen demand (COD), odor, and color occur. If Fenton's Chemistry is allowed to be carried to completion, then all organic molecules will ultimately be broken into carbon dioxide and water. Fenton's Chemistry is a nonselective oxidizer. Fenton's Chemistry is also called Fenton's Reagent in the literature.

Soils contaminated with toxic and recalcitrant organic wastes such as petroleum hydrocarbons and chlorinated solvents can be effectively treated with Fenton's Chemistry.
In situ
chemical oxidation (ISCO) uses contact chemistry of the oxidizing agent to react with petroleum hydrocarbons, volatile organic compounds, munitions, certain pesticides, and wood preservatives in the vadose zone or in the groundwater. The gasoline including benzene, the gasoline additive, methyl tertiary butyl ether (MtBE), as well as a variety of chlorinated solvents such as tetrachloroethylene (PCE), trichloroethylene (TCE), and other synthetic compounds have been shown to break down with Fenton's Chemistry.
Advanced Water Main Deterioration Model Using Bayesian Geoadditive Quantile Regression
Authors: Balekelayi Ngandu , Tesfamariam Solomon
Published: December 2019

Once installed, water pipes “condition degrade” until failure. Utility managers anticipate the failure of water mains through a proactive management of urban water systems. In proactive management, deterioration models are used to predict the actual condition of uninspected pipes and forecast the future condition of all the pipes in the network. For an efficient planning, these models' predictions should be as close as the observed conditions of pipes during inspections. High‐degree polynomials can capture the complexity of water pipes deterioration process. However, these polynomials wiggly estimate such relationships and are unsatisfactory in some regions where they fail to fit the observed data. Flexible regression techniques that enable automatic data‐driven estimation of nonlinear relations between covariates and response constitute an alternative approach that can represent the stochastic deterioration process. In this article, a semiparametric deterioration model based on geoadditive quantile regression with smooth nonlinear function estimation of the effects of continuous covariates is proposed. The results confirm the nonlinear assumption of the continuous covariates and highlight factors contributing to the appearance of extreme values in the response variables. Maps representing the effects of the unobserved covariates on the pipes breakage rate are also produced.
Biofilm Formation in Water Supply Pipes
Authors: Xiao Yeyuan , Waheed Hira
Published: December 2019

Biofilm formation in water supply pipes is ubiquitous despite the practice of keeping a certain level of disinfectant residual. Biofilms in water supply pipes play a dominant role in shaping the microbial community and governing the microbial quality of tap water. However, this role has long been overlooked largely due to the unavailability ofin situbiofilm monitoring tools and complexity of biofilm ecology. Recent development in molecular biology techniques has opened up a new window for biofilm studies, and thus sparked a new boom in research on biofilms in water supply pipes. This article introduces the new knowledge of occurrence and significance of biofilms in water supply pipes, their impacts on water quality and relationships with pipe corrosion. Then the factors affecting biofilm formation and methods to control it are elaborated. Furthermore, new insights into the microbial ecology of biofilms are presented, which include the dominant microorganisms and their potential roles in biofilms, the diversity and richness of the microbial communities, etc. At the end, future perspectives of research on biofilms in water supply pipes are discussed.
Coastal Oceanography: Physics and Biology
Authors: Wang Xiao Hua , Gao Yue Xin , Wang Qian , He Tianqi , Guan Weibing , Chai Fei
Published: December 2019

Many world estuaries and coastal environments are under tremendous stress in response to the increased anthropogenic forcing and climate change. A good understanding of the current state of these marine environments and lessons learnt from these human influences would be extremely valuable to restore and protect these habitats and ecosystems from further environmental degradation and catastrophe. This article provides a synthesis in which the latest research addressing the physics, sedimentary processes, biology, chemistry, and ecological processes is associated with these rapidly changing estuarine and coastal environments. It will explore the challenges and opportunities for future research in China's estuaries and coastal waters around the world.
Climate Change and Agriculture
Authors: Todorović Mladen , Jovanović Nebojša
Published: December 2019

Climate change impacts on agriculture are driven by many complex factors and feedback mechanisms. The principal climate change processes influencing agriculture are global warming, elevated CO2, air pollution, and changes in precipitation patterns. The main effects are increased potential crop productivity through CO2fertilization, changes in crop growth and development through temperature increase, phytotoxicity due to air pollutants such as O3, and increased risks of extreme events (droughts, floods, heat waves, cyclones, etc.). This results in socioeconomic impacts such as reduced profits, changes in the price of agricultural products, food insecurity, and population displacement and migration. A large set of “climate‐smart” technical and institutional measures are proposed in order to mitigate/adapt to climate change both for crop and livestock production. Such measures are beneficial to agriculture regardless of climate change (“no regret actions”) and they cover both the biophysical and socioeconomic spheres in order to facilitate the uptake by practitioners. Scientific efforts should be strengthened in order to address research gaps (e.g. predictive modeling at local scale, the impacts of climate change on complex processes such as pest and disease occurrence) and to promote capacity building and public awareness on climate change impacts to agriculture, mitigation, and adaptation measures.
Water Infrastructure and Asset Management
Authors: Kabir Golam , Tesfamariam Solomon , Sadiq Rehan
Published: December 2019

Health, safety, and economic prosperity of the citizens of any country are ensured with services provided by core public infrastructures such as water, roads, transit, bridges, and wastewater. The water infrastructures are linear systems, among the most important and expensive municipal infrastructure assets. Maintaining integrity and reliability of water infrastructures is the primary goal of water utilities, governmental agencies, and other stakeholders. It has been quite challenging to maintain the integrity and reliability of water infrastructures because of the aging, aggressive environmental factors, climate change, improper maintenance and renewal, and resource shortages. In this article, the asset management framework for the water infrastructures has been discussed. The main objective of the asset management framework is to provide a desired level of service at a minimum cost. The asset management framework will provide the water utility with the capacity to make informed decisions based on the current and anticipated future performance of the asset. This framework will also help the water utility to improve strategic, tactical, and operational planning‐level decisions considering different dimensions of analysis such as performance, risk, and cost analysis.
Water Supply Systems: Performance Indicators
Authors: Haider Husnain , Sadiq Rehan
Published: December 2019

A water utility consists of different key components (to operate one or more water supply systems in its geographical jurisdiction), including water resources and environmental, physical assets, operations, public health, services, personnel, and finance. Performance of these components can be assessed using suitable performance indicators (PIs). Indicators should be cautiously selected based on their relevance, measurability, and comparability for both the inter‐utility benchmarking and Intra‐utility performance assessment. Inter‐utility benchmarking process may generate long documentation presenting the comparisons of several indicators. Conversely, performance indices are generated by aggregating the PIs at the component level, which are more convenient to top‐level utility's management, policy makers, and the general public. Operations managers are more engrossed in the underlying processes. Intra‐utility performance assessment informs about the performance of subcomponents for each water supply system operating in a utility's dominion. Knowledge shared in this article reveals that effective use of PIs can contribute to the overall sustainability of our water supply systems. More recent applications, (i) multilevel performance assessment, (ii) risk‐based benchmarking, and (iii) continuous performance improvement, are also discussed.
The 2010 Marshall, Michigan Tar Sands Oil Spill
Authors: Insko Jeffrey
Published: December 2019

On 25 July 2010, an oil pipeline transporting diluted bitumen from the tar sands region of Alberta, Canada ruptured near Marshall, Michigan. Over the course of 17 hours, oil gushed from a six‐foot seam in the pipeline. By the time personnel from the pipeline company Enbridge, Inc., finally realized the line was compromised, over a million gallons of oil had spilled into Talmadge Creek, a tributary of the Kalamazoo River. The oil traveled almost two miles down the creek and entered the river, which flows some 130 miles in a northwesterly direction until it reaches Lake Michigan. Because a spill of this type and magnitude had never before occurred in a body of fresh water, it would ultimately take nearly seven years and cost more than a billion dollars to clean it up, making it the costliest inland oil spill in the US history. The Marshall spill is significant for what it taught scientists, industry, and the public about the behavior of diluted bitumen in fresh water, for bringing into visibility the threats posed by the nation's vast pipeline infrastructure to sensitive freshwater resources, and for its bellwether role in North American grassroots and indigenous movements focused on water protection.
Co‐Digestion of Food Waste at Wastewater Treatment Plants
Authors: Martis Mary , Leverenz Harold , Raibley Tim , Thomas Brian , Roa Amanda
Published: December 2019

It is well established that the addition of food waste and similar feedstock to municipal wastewater anaerobic digesters, a practice known as co‐digestion, can be used to increase the production of biogas. The purpose of this report is to provide an overview of the practice and considerations for food waste co‐digestion for engineers and planners. Items discussed include the rationale for the practice of co‐digestion, including legal requirements, excess capacity, potential revenue, and sustainability goals. Details on food waste sources, conducting a food waste survey, and food waste collection programs are discussed. This report also contains a review of considerations for food waste loading to an anaerobic digester, including potential challenges and costs.
Water Distribution Systems: Hydraulics and Quality Modeling
Authors: Mian Haroon R. , Saleem Sana , Hu Guangji , Sadiq Rehan
Published: December 2019

Water is considered one of the key elements of life. It is important to deliver, manage, and maintain the quantity and quality of drinking water for safe ingestion. Water is supplied through a water distribution system (WDS), which delivers water from the source to end consumers with required flow and pressure. Moreover, water treatment is applied to maintain the quality of water. To achieve the required water quantity and quality, it is important to evaluate the conditions of water in WDS. Motivated by rapid population growth and urbanization, city planners, designers, and engineers are more interested in evaluating water quantity and quality in the planning phase. Development of models (numerical or conceptual) has become a widely recognized approach for any system, especially in the evaluation stage. Several models have been developed in the context of WDS to evaluate water quantity and quality, and most of these have been developed based on real‐world water sampling data. This article comprehensively reviews the existing hydraulic and quality models that have been applied in various WDSs. Some of the commonly used water modeling software used in WDS hydraulic and quality designs are also listed.
Water Quality Failure Pathways
Authors: Hu Guangji , Mian Haroon R. , Hager James , Sadiq Rehan
Published: December 2019

Water utilities around the globe strive to provide safe and reliable drinking water supplies to the public. Based on human health and aesthetic considerations, various water quality parameters have been developed by the World Health Organization (WHO) for effective water quality monitoring and communication. The water quality parameters are listed in the Guidelines for Drinking‐water Quality, providing references to water regulatory authorities in developing water guidelines/standards that fit local circumstances. Water quality parameters can generally be divided into four aspects, including chemical, biological, radiological, and acceptability parameters. Water quality failure in water distribution systems (WDSs) can pose great threats to human health since a WDS in many cases is the last barrier providing water quality protection. In WDSs, five important pathways, including contaminant intrusion, leaching and corrosion, permeation, biofilm formation and microbial regrowth, and the formation of disinfectant byproducts (DBPs), are responsible for water quality failure. A water quality management system (WQMS) comprises operational protocols and communication mechanisms and is required as guidance on effective water quality management. A WQMS standard has also been recommended by the WHO to assist water supply stakeholders in developing localized water quality management frameworks to minimize the risk of water quality failure.
Water Desalination: Electrostatic and Electrochemical Separation Processes
Authors: Shanbhag Sneha , Karimi Leila , Whitacre Jay F. , Mauter Meagan S.
Published: December 2019

Electrostatic and electrochemical separations offer significant potential in the deionization of water as either stand‐alone processes or pre‐/posttreatment processes for achieving targeted water quality. This article critically reviews these electrically driven methods for the desalination of water. We begin by chronicling the historical development of electrostatic and electrochemical separation processes in both research and commercial applications. Further, we review the fundamental transport and reaction phenomenon critical to process performance and define metrics for assessing this performance. The subsequent two sections provide a deeper review of CDI (electrostatic) and electrosorption (electrochemical ion removal), and electromembrane separation systems, such as electrodialysis (ED), electrodialysis reversal (EDR), and electrodeionization (EDI), as well as membrane‐assisted electrosorption systems. For each of these electrostatic or electrochemical separation methods, we discuss the process fundamentals, key challenges associated with these technologies as well as recent innovations in materials and process design that are overcoming historical limits. Finally, we conclude with a discussion of practical applications of these methods and summarize opportunities to advance electrochemical processes for materially and energy‐efficient ionic separations.
Drinking Water Treatment Unit Processes: Computational Fluid Dynamics Modeling
Authors: Ladner David A. , Zhou Zuo , Xie Peng
Published: December 2019

The conventional drinking water treatment plant train of unit processes includes an intake structure, rapid mix, flocculation, sedimentation, granular media filtration, disinfection, and distribution. As populations grow and unconventional sources of water are sought, alternative unit processes are becoming more common, such as ozonation and reverse osmosis. Novel ideas to accomplish certain goals in the treatment plant have resulted in modified processes that function differently than their conventional counterparts; static mixers are one example. With this changing landscape of drinking water treatment, it behooves engineers to use modern tools to compare options and optimize their designs. Computational fluid dynamics (CFD) modeling is a method for accomplishing those goals. This article discusses CFD modeling in the context of the above drinking water treatment plant unit processes. The most common software packages are discussed, including ANSYS Fluent, COMSOL Multiphysics, and OpenFOAM. With each unit process, the goals of CFD modeling are explored. Some common threads emerge among processes, such as the utility of identifying dead zones or eddies in vessels and the importance of calculating shear and mixing intensity. This article thus serves as an overview for practitioners or others interested in using CFD as a drinking‐water treatment plant design tool.
Overview of Drinking Water Distribution System Microbiome and Water Quality
Authors: Gomez Christa K. , Aggarwal Srijan
Published: December 2019

After treating the source water at the water treatment plant, the water is distributed to the consumer through the large network of drinking water distribution system pipes and mains. Since the water can spend days to weeks in this buried infrastructure, there is a possibility of introduction of recontamination or undesirable biological growth in the treated water. There needs to be a delicate balance among the three components of this system: water, microbiome, and the infrastructure itself; with the overarching goal to provide high‐quality drinking water to ensure public health and safety. There exists a strong interplay and feedback among these three components, each impacting the other. While drinking water treatment revolutionized public health in the last few decades, in the United States we are currently dealing with an aging water infrastructure which is nearing the end of its life – making it all the more important to understand the processes that impact water quality during distribution. In this article, we provide an overview of factors and processes that govern the microbial communities and biofilms in the distribution system, and thereby impacting water quality – by revisiting key concepts and highlighting new information as well as future directions.
Water Distribution System
Authors: Saleem Sana , Mian Haroon R. , Hu Guangji
Published: December 2019

Providing sufficient water with appropriate quality has been an important challenge in human history. This challenge has become more significant in recent years due to increased water demands as a result of global population growth. To address the challenge, water infrastructure, known as water supply system, has been specially designed to provide a sufficient supply of clean water to the public. A water supply system broadly consists of four components: collection works, treatment works, transmission works, and distribution works. Among these components, distribution works, also collectively known as a water distribution system (WDS), is recognized as one of the main components of the water supply system. WDS comprises pipes, storage tanks, valves, and pumps. A WDS can be very complex because different types of components are used and different areas may have different water demands. Many efforts have been made to improve WDSs for better water supply services. These studies developed some design parameters to ensure reliable, long‐range operations of WDSs. This article classifies WDSs according to their sizes and components and highlights some key challenges related to the operation and management of WDSs.