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Regional patterns of the seasonal weather and atmospheric moisture origins can impact the seasonal activities of extreme precipitation in the eastern United States (eUS). At many locations, tracks of atmospheric moisture can have different influence on timing of extreme precipitation based on the moisture origin source. In this study, we evaluate the contribution of atmospheric rivers (ARs) and their moisture origin sources to the distribution and seasonal effectivity of annual maximum precipitation (AMP) across the eUS during 1950–2021. Our results suggest that AR is a dominant mechanism of AMP in the eUS as it contributes to 75% (31 438 out of 41 976) of total AMP events recorded between 1950 and 2021. The seasonal analysis based on the circular density approach shows that spring, summer, and fall seasons display strong signals of seasonality of AMP-AR events. The spatial patterns of AMP associated with the four major moisture sources (the Pacific Ocean, the Atlantic Ocean, the combined source of the Caribbean Sea and the Gulf of Mexico, and the local source of moisture) reinforce the key role ARs play in transporting water vapor to the eUS from both oceanic and inland originated moisture. The results additionally highlight the importance of moisture subsources (major source subregions) in modulating the seasonality of extreme precipitation in the eUS. [ABSTRACT FROM AUTHOR]

Temporal changes in the seasonality of extreme precipitation, and possible teleconnections between the seasonality of extreme precipitation and large‐scale climate patterns are not well understood. In this study, we investigated temporal changes in seasonality of annual daily maximum (ADM) and monthly maximum (MM) precipitation indices over the period 1951–2014 for 1,108 stations across the contiguous USA. We also examined seasonality of extreme precipitation during negative and positive phases of three major oscillations: the El Niño–Southern Oscillation, the Northern Atlantic Oscillation, and the Pacific Decadal Oscillation. Our results show that many climate regions within the contiguous USA display distinct seasonality for both ADM and MM. Comparison of seasonality between two historical records of equal length, that is, before and after 1981, shows great spatial variability across the contiguous USA. While a spatial coherence of change in the mean date of occurrence of extreme precipitation across a large area is not visible, a cluster of stations showing decrease in strength of seasonality for the recent period is concentrated in the eastern Gulf Coast and coastal sites of Northeast and Northwest regions. Extreme precipitation seasonality during negative and positive phases of three climate indices revealed that large‐scale climate variabilities have a strong influence on the mean date of occurrence of extreme precipitation but generally weak influence on the strength of seasonality in the contiguous USA. Results from our study might be helpful for sustainable water resource management, flood risk mitigation, and prediction of future precipitation seasonality. [ABSTRACT FROM AUTHOR]

Global warming is likely to provoke extreme storms in the eastern United States (eUS), ultimately affecting the probabilistic distribution of the dates of daily maximum precipitation. In this study, probabilistic properties of timing of annual maximum precipitation (AMP) were studied using circular statistics at 583 sites in the eUS (1950–2019). A kernel circular density method was applied to examine distributional modes of timing of AMP. The results of circular median show that seasonality is pronounced across the eUS with many locations having their median date of occurrence in summer, and AMP seasonality is strong in the East North Central region. Similarly, results of circular density method applied to the distribution of AMP timing shows that around 90% of the sites have two or three modes of AMP seasonality in the eUS. Comparison of seasonality between two historical records of equal length (1950–1984 and 1985–2019) shows great spatial variability across the eUS. Temporal changes in seasonal modes for AMP dates revealed four different cases of seasonality changes: (i) weakening of seasonality, (ii) strengthening of seasonality, (iii) strong seasonality for both the old and recent periods, (iv) or uniform or no preferred seasonality for both periods. While a spatial coherence of seasonality changes was not observed, majority of sites showed strong seasonality (case iii) for old and recent periods mainly during summer and fall seasons. [ABSTRACT FROM AUTHOR]

In the eastern United States, the empirical probability distribution of extreme daily precipitation comprises heavy rainfall events stemming from North Atlantic tropical cyclones (TCs). At many locations, these events influence estimates of extreme value statistics (e.g., 100‐year event), thus have important bearing on the sizing of flood protection infrastructure and, in general, flood risk management and preparedness. Consequently, a characterization of location specific and regional patterns in precipitation extremes and changes therein has salience for both scientific and engineering concerns. To this end, analysis of seasonal and annual maximum daily precipitation at 667 long‐term stations across the eastern United States was pursued to ascertain recent changes in the extreme events over the 1950–2011 period. Three key results from this study illuminate less understood facets of recent changes in precipitation extremes: (a) an overall increase in the fraction of seasonal and annual maximum precipitation events linked to TCs, (b) a dramatic increase in the correlation between Accumulated Cyclone Energy Index and the leading principal component of extreme precipitation, and (c) changes in the spatial patterns of regions with highest TC‐related risk for heavy precipitation. [ABSTRACT FROM AUTHOR]

Changes in extreme precipitation are associated with changes in their probability distributions and the characteristics of quantiles derived from fitted distributions. In this study, the linear quantile regression method is employed to analyse spatio‐temporal trends of extreme precipitation and to study the impact of North Atlantic tropical cyclones in the distribution of extreme precipitation for the southeastern United States. Daily annual maximum precipitation over the period of 64 years (1950–2013) for 107 sites was used for the analysis. Our results show that changes in upper quantiles of the distributions of the extreme precipitation have occurred in the southeastern United States. Analysis of the potential changes in the distribution of the extreme precipitation by separating the historical record into two periods, that is, before and after 1981, reveals that upper‐quantile trends have increasing magnitude in most of the sites for the latest time period. Analysis of the impact of tropical cyclones in the extreme precipitation distribution shows that overall the heavy rainfall events in the recent decades may have been caused by tropical cyclones. Such results are particularly useful for water managers who are more concerned with extreme values rather than the averaged one. Hence, our study has significant implication in environmental and infrastructural assessment as well as disaster risk management. [ABSTRACT FROM AUTHOR]

Controlling fouling in seawater reverse osmosis and ultrafiltration systems is a major challenge during algal blooms. This study investigates UF fouling potential of four marine algae and their algal organic matter (AOM): Chaetoceros affinis (Ch), Rhodomonas balthica (Rh), Tetraselmis suecica (Te), and Phaeocystis globulosa (Ph). Batch culture monitoring of the four different marine algal species showed remarkable differences in their production of biopolymers, transparent exopolymer particles (TEP) and their membrane fouling potential (MFI-UF 10 kDa ). MFI-UF 10 kDa was linearly related to biopolymer concentration, and TEP during the growth and stationary/death phase of all four algal species. But the linear relation of MFI-UF 10 kDa with algal cell density and chlorophyll-a concentration did not continue during the stationary/death phase. In experiments with capillary UF membranes, non-backwashable fouling of UF membranes varied strongly for the four different AOM solutions tested, and was linked to the presence of polysaccharides (stretching-OH) and sugar ester (stretching S˭O) groups in the AOM. The non-backwashable fouling coincided with MFI-UF 150 kDa and TEP concentration. Therefore, determination of these parameters (MFI and TEP) and correlating with MODIS satellite data may generate useful information about the fouling potential of seawater at different locations during an algal bloom. [ABSTRACT FROM AUTHOR]

This study aims at applying and verifying the MFI-UF method to predict particulate fouling in RO plants. Two full-scale RO plants treating surface water, with average capacity of 800–2000 m3/h, were studied. Firstly, the MFI-UF of RO feed and concentrate was measured using 5–100 kDa membranes at same flux applied in the RO plants (20–26 L/m2.h). Subsequently, the particle disposition factor (Ω) was calculated to simulate particle deposition in RO cross-flow filtration. Finally, particulate fouling rates were predicted based on MFI-UF and Ω , and compared with the actual fouling rates in the plants. For plant A, the results showed that the fouling rates predicted using MFI-UF measured with 100 kDa membrane have the best agreement with the actual fouling (with 3–11 % deviation). For plant B, the fouling rates predicted based on both 10 and 100 kDa membranes agree well with the actual fouling (with 2 % and 15 % deviation, respectively). However, the fouling predicted based on 5 kDa membrane is considerably overestimated for both plants, which is attributed to the effect of the low surface porosity of 5 kDa membrane. More widespread applications of MFI-UF in full-scale RO plants are required to demonstrate the most suitable MFI-UF membranes for fouling prediction. • MFI-UF method was used to predict particulate fouling rate in full-scale RO plants. • 10–100 kDa UF membranes can be used in MFI-UF test to predict particulate fouling. • The variation between the predicted and actual fouling rates in RO plants was <15 %. • Accuracy of fouling prediction depends highly on the flux consistency in RO plants. [ABSTRACT FROM AUTHOR]

This study aimed to quantify the effect of membrane surface porosity on particulate fouling predicted by the MFI-UF method at constant flux. Firstly, the surface porosity of polyethersulfone UF membranes (5–100 kDa) was determined using ultra-high resolution SEM. Thereafter, the MFI-UF was measured using suspensions of polystyrene particles (75 nm), which were pre-washed to remove surfactant and particle fractions smaller than the pores of MFI-UF membranes, thus ensuring complete retention of particles during MFI-UF measurements. Consequently, the MFI-UF values of washed polystyrene particle suspensions were independent of the pore size and depended only on the surface porosity of MFI-UF membrane. The results showed that the membrane surface porosity decreased with MWCO from 10.5% (100 kDa) to 0.6% (5 kDa), and consequently the MFI-UF increased from 3700 to 8700 s/L2, respectively. This increase in MFI-UF was attributed to the non-uniform distribution of membrane pores, which is exacerbated as surface porosity decreases. Consequently, preliminary correction factors of 0.4–1.0 were proposed for MFI-UF measured with UF membranes in the range 5–100 kDa. Finally, the surface porosity correction was applied to predict particulate fouling in a full-scale RO plant. However, additional research is required to establish correction factors for different types of feed water. [Display omitted] • Novel approach allows quantification of membrane surface porosity effect on MFI-UF. • Washed polystyrene particles were used to investigate the surface porosity effect. • Effect of surface porosity depends on how uniform the pores are distributed. • Low membrane surface porosity can result in overestimation of measured MFI-UF value. • Surface porosity correction improved particulate fouling prediction in an RO plan. [ABSTRACT FROM AUTHOR]

The rational method for peak discharge () estimation was introduced in the 1880s. The runoff coefficient () is a key parameter for the rational method that has an implicit meaning of rate proportionality, and the has been declared a function of the annual return period by various researchers. Rate-based runoff coefficients as a function of the return period, , were determined for 36 undeveloped watersheds in Texas using peak discharge frequency from previously published regional regression equations and rainfall intensity frequency for return periods of 2, 5, 10, 25, 50, and 100 years. The values and return period adjustments determined in this study are most applicable to undeveloped watersheds. The return period adjustments determined for the Texas watersheds in this study and those extracted from prior studies of non-Texas data exceed values from well-known literature such as design manuals and textbooks. Most importantly, the return period adjustments exceed values currently recognized in Texas Department of Transportation design guidance when . [ABSTRACT FROM AUTHOR]

Extreme climate events disrupt the stable, established interactions among the components of the socio-economic and environmental systems. The disruptions affect reaching the targets defined by the United Nations Sustainable Development Goals 1, 2, 6, and 7 that aim at ending poverty and hunger and ensuring access to clean water, sanitation, and affordable energy. We have semantically modeled the interactions of climate change events with the components of the food, water, and energy systems in the 'Sustainable Development and Climate' (SDC) ontology. The domain ontology formalizes the impacts of the events on the implementations of the actions, plans, strategies, and policies that are described by the targets of the selected goals. To ensure interoperability with other ontologies, our ontology extends classes and properties of the top-level Basic Formal Ontology, mid-level Common Core Ontologies, and other upper-level ontologies. The publicly-available SDC ontology facilitates automated discovery, management, integration, and reasoning of the indicator data of the selected goals by reusing the extensive resources of the Common Core Ontologies for data and information modeling. The SDC knowledge model allows government agencies to identify the consequences of their planned actions on people, resources, and the environment in their country, and assess the impacts of the current climate change on the successful implementation of the requirements for goals 1, 2, 6, and 7. [ABSTRACT FROM AUTHOR]

The rational method for peak discharge (Qp) estimation was introduced in the 1880s. Although the rational method is considered simplistic, it remains an effective method for estimating peak discharge for small watersheds. The runoff coefficient (C) is a key parameter for the rational method and can be estimated in various ways. Literature-based C values (Clit) are listed for different land-use/land cover (two words, no hyphen) (LULC) conditions in various design manuals and textbooks; however, these Clit values were developed with little basis on observed rainfall and runoff data. In this paper, Clit values were derived for 90 watersheds in Texas by using LULC data for 1992 and 2001; the Clit values derived from the two data sets were essentially the same. Also for this study, volumetric runoff coefficients (Cv) were estimated by using observed rainfall and runoff depths from more than 1,600 events observed in the watersheds. Watershed-median and watershed-average Cv values were computed, and both are consistent with data from the National Urban Runoff Program. In addition, Cv values were estimated by using rank-ordered pairs of rainfall and runoff depths (i.e., frequency matching). As anticipated, C values derived by all three methods (literature based, event totals, and frequency matching) consistently had larger values for developed watersheds than for undeveloped watersheds. Two regression equations of Cv versus percent impervious area were developed and combined into a single equation that can be used to rapidly estimate Cv values for similar Texas watersheds. [ABSTRACT FROM AUTHOR]

Measuring the bacterial growth potential of seawater reverse osmosis (SWRO) feed water is an issue that is receiving growing attention. This study developed and demonstrated the applicability of the flow-cytometry (FCM)-based bacterial growth potential (BGP) method to assess the biofouling potential in SWRO systems using natural microbial consortium. This method is relatively fast (2–3 days) compared to conventional bioassays. The effect of the potential introduction of nutrients during measurement has been studied thoroughly to achieve the lowest measure value of about 45,000 cells/mL, which is equivalent to about (10 µg-C glucose/L). The BGP method was applied in two full-scale SWRO plants that included (i) dissolved air flotation (DAF) and ultra-filtration (UF); (ii) dual-media filtration (DMF) and cartridge filter (CF), which were compared with the cleaning frequency of the plants. A significant reduction (54%) in BGP was observed through DAF–UF as pre-treatment (with 0.5 mg Fe3+/L), while there was a 40% reduction by DMF–CF (with 0.8 mg Fe3+/L). In terms of the absolute number, the SWRO feed water after DAF–UF supports 1.5 × 106 cells/mL, which is 1.25 times higher than after DMF–CF. This corresponds to the higher cleaning-in-place (CIP) frequency of SWRO with DAF–UF compared to DMF–CF as pre-treatment, indicating that the BGP method has an added value in monitoring the biofouling potential in SWRO systems. [ABSTRACT FROM AUTHOR]

Various bacterial growth potential (BGP) methods have been developed recently to monitor biofouling in seawater reverse osmosis (SWRO) systems such as assimilable organic carbon and bacterial regrowth potential. However, the relationship between these methods and biofouling in SWRO desalination plants has not yet been demonstrated. In this research, an attempt is made to investigate if a correlation exists between BGP of SWRO feed water and the chemical cleaning frequency in SWRO plants using an ATP-based BGP method employing an indigenous microbial consortium. Using ATP-based BGP method at 5 different seawater locations showed low variations of bacterial yield. The BGP method was applied to assess the pretreatment performance of three full-scale SWRO plants with different pretreatment processes. Dual media filtration (DMF) showed the highest BGP removal (>50%) in two SWRO plants. Removal of BGP and hydrophilic organic carbon in dissolved air floatation combined with ultrafiltration was similar to the removal achieved with DMF in combination with inline coagulation. For the three SWRO plants investigated, a higher BGP in SWRO feed water corresponded to a higher chemical cleaning frequency. However, more data is required to confirm if a real correlation exists between BGP and biofouling in SWRO plants. • BGP in seawater was measured using ATP with indigenous microbial consortium. • Bacterial growth in seawater correlated to the added glucose concentration. • BGP was monitored through the pretreatment of three full-scale SWRO plants. • Higher BGP in SWRO feed corresponded to a higher CIP frequency in three SWRO plants. [ABSTRACT FROM AUTHOR]

The FEWsOnt ontology models major structural and dynamic concepts of the food–energy–water (FEW) systems from the complex system perspective by defining the emergent, nonlinear, and scale-invariant state transitions and behaviors of the network elements that result from natural and planned processes. The model represents the semantics of concepts such as security, footprint, challenge, risk, impact, and uncertainty in relation to governance and assessment of the level of sustainability of the FEW systems in varied domains of usage. The ontology will allow stakeholders working with the FEW systems' data to draw new inferences using semantic facts and discover insights and relationships among the systems' elements to make improved assessment and decisions toward sustainable growth. The knowledge-based model will lead users to optimize the tradeoffs and identify and prevent adverse changes to the FEW systems in relation to the interacting natural and social systems. The annotated terminology and formalized interactions in the ontology will facilitate the integration of the diverse FEW data types, improve communication among researchers, and help to reduce environmental stresses. [ABSTRACT FROM AUTHOR]

Abstract For assessing the particulate fouling of water, the modified fouling index (MFI 0.45) is a superior test to the silt density index (SDI). There is a need to compare both tests in terms of sensitivity, how they are affected by the filter material and the type of support plate and also illustrate their use for monitoring of seawater quality over time. In this work, we studied seven different filter holders with different filter support plates and three different 0.45 μm filter materials, and we applied the tests for monitoring of North Sea water quality. The results illustrated that the type of support plate of the filter holder greatly influences the measured MFI 0.45 values and thus, a correction for the effective membrane area may be needed when carrying out an MFI 0.45 test. An attempt to normalize differences in MFI 0.45 due to filter material with a Formazin solution was tested but proven not successful. When monitoring the seawater, the MFI 0.45 was much more sensitive than SDI to water quality variations in particular during algal growth. As the SDI and MFI 0.45 tests can be measured with help of the same equipment, more alignment in the ASTM protocols for both methods is recommended. Highlights • The filter material influences the measurements of SDI and MFI 0.45. • The type of support plate and holder influence the measurements of MFI 0.45 and correction might be needed. • MFI 0.45 can be used to predict rate of RO fouling but is not sensitive enough. • MFI 0.45 was more sensitive to changes in water quality than SDI when monitoring North Sea water. [ABSTRACT FROM AUTHOR]

Concept of integrated brackish water batch reverse osmosis – forward osmosis (BRO – FO) is relatively new in the field of desalination. Recovery of the reverse osmosis (RO) system can be elevated using the free piston BRO concept, and the specific energy consumption (SEC) can be reduced. This study focuses on exergy, advanced exergy, and parametric analysis of the integrated BRO - FO system. The conventional exergy analysis suggests that the largest rate of exergy destruction is associated with the system's RO membrane module and pump, with values of 6.51 and 87.06 %, respectively. However, advanced exergy analysis shows that this rate can be reduced by 3.53 % and 62.89 %, respectively. Endogenous exergy destruction of pumps and membranes is higher compared to exogenous exergy destruction. These results are utilised to determine the system's optimal performance using parametric analysis. Sensitivity analysis was utilised to obtain an optimum recovery for system design, fresh water cost (FWC), and specific solution cost (SSC). The BRO can achieve >80 % recovery with 0.43 kWh/m3 SEC, and FO technology helps to attain minimal/zero waste discharge. Thus, a FWC of 0.50 $/m3 and a SWC of 0.44 $/m3 can be achieved. [Display omitted] • Quantified exergy destruction for optimization of an integrated BRO - FO system • Dual approach: Desalination and waste reuse with integrated BRO - FO system • Identified optimum recovery of BRO system for integrated operation • Determined minimum FWC and SSC at optimal recovery and specific energy consumption [ABSTRACT FROM AUTHOR]

Batch RO is a concept for achieving the minimum possible energy consumption in desalination, even at high recoveries. We present a batch RO design that operates cyclically in two alternating phases. The system uses a free piston, housed in a pressure vessel, to transfer pressure from the feed fluid to the recirculating fluid. No complete design procedure for this configuration currently exists. To fill this gap, we present a systematic model based on justified assumptions. The specific energy consumption (SEC) is broken down into contributions from the feed pump, recirculating pump, and auxiliary loads. The calculation of feed pump SEC includes three non-ideal correction factors: concentration polarisation, longitudinal concentration gradient, and salt retention. The model requires only the solution of explicit algebraic equations, without need of specialised numerical techniques, and is implemented in a simple 3-step procedure. The model is applied to an example involving desalination of brackish water using an 8-inch spiral-wound RO module. The design parameters are explored and optimised in a sensitivity analysis. The results show that the optimised batch RO at 80% recovery can produce fresh water with low-energy consumption, achieving 2nd law efficiency of 33.2% compared to 10–15% for conventional brackish water RO. Unlabelled Image • A detailed procedure for batch RO design favours large-scale brackish water desalination. • A model for designing the system using explicit algebraic equations • Feed and recirculation pump contribute respectively major and minor amounts to SEC. • The optimum recirculation flow is 2–3.5 times the permeate flow to minimise SEC. • The system gives high 2nd law efficiency compared to conventional RO. [ABSTRACT FROM AUTHOR]

Pollution is a major issue impacting the health of life and ecosystems. In particular, some pollutants may alter gene expression by epigenetic mechanisms such as deoxyribonucleic acid (DNA) methylation, histone modifications, and microRNA (miRNA) expression. Epigenetics is the study of heritable changes without alteration in the DNA sequence. In the healthy state, the coordinated actions of interconnected epigenetic factors are responsible for proper cell development and cell regulation. Epigenetic mechanisms are tissue-specific; hence, a pollutant may or may not cause an alteration depending on the type of tissue. Here we review mechanisms by which pollutants disrupt epigenetic factors. We focus on the impact of arsenic, cadmium, nickel, mercury, benzene, bisphenol A, dioxin, hexahydro-1,3,5-trinitro-1,3,5-triazine and diethylstilbestrol. A list of diseases related to epigenetic factors and heavy metals exposure is provided. [ABSTRACT FROM AUTHOR]

The modified rational method (MRM) is an extension of the rational method to develop triangular and trapezoidal runoff hydrographs. A trapezoidal unit hydrograph (UH) was developed from the MRM for the case when the duration of rainfall is less than the time of concentration of the watershed and is called the modified rational unit hydrograph (MRUH). The MRUH method was applied to 1400 rainfall-runoff events at 80 watersheds in Texas. Application of the MRUH method involved three steps: () determination of rainfall excess using the runoff coefficient; () determination of the MRUH using drainage area and time of concentration; and () simulating event runoff hydrographs. The MRUH performed as well as the Gamma function UH, Clark-HEC-1 UH and NRCS curvilinear UH methods when the same rainfall loss model was used. The MRUH method can be applied to time-variable rainfall distributions and at watersheds with drainage areas greater than typically used for the rational method (a few hundred acres). [ABSTRACT FROM AUTHOR]