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The role of steric hindrance and charge interactions in governing ionic transport through reduced graphene oxide (rGO) and commercial (DOW-Filmtec NF270) membranes was elucidated by a comprehensive study of experimental and established mathematical analysis based on Nernst-Planck equation. A charge-dominated salt exclusion mechanism was observed for the rGO membranes, which exhibited retention from low (7%) to moderate (70%) extent depending on the nature of ions (5 mM). Swelling of GO (1.2 nm interlayer distance) in water beyond the hydrated diameter of ions was attributed as a primary cause for lowering steric hindrance effects. The influence of parameters affecting charge interactions, such as pH and ionic strength, on the extent of salt rejection was modelled. The potential impact of the membranes charge density, GO loading and interlayer spacing on salt retention was quantified by performing sensitivity analyses. For a high TDS produced water sample, the rGO membranes partially retained divalent cations (Ca:13%) and exhibited high dissolved oil rejection. The membranes were found to be suitable for the treatment of high TDS water with the goal of selectively removing organic impurities, and thus minimizing the impact of osmotic pressure effect. Performance of the membranes was also investigated for retention of water remediation related organic anions, using perfluoro octanoic (PFOA) acid as a model compound. rGO membranes exhibited a charge-dominated exclusion mechanism for retention (90%) of PFOA (1 ppm).

The NIEHS-sponsored "Appalachian Health & Well-Being Community Forum" held in Eastern Kentucky brought various community members together to communicate and establish better coordination of efforts to improve health and address regional environmental issues. The 2-hour forum discussion provided bi-directional feedback about the needs and interests of community members. Top concerns of community members included obesity and obesity-related diseases and environmental pollution. Healthful lifestyles were identified as part of the remedy to protect health from potential adverse health effects associated with environmental pollution. This study highlights opportunities to engage with Appalachian communities around topics related to health and environmental pollution.

Key Takeaways: Kentucky, like other states, faces growing challenges in recruiting and retaining qualified water operators. A recent survey of managers and operators from Kentucky water utilities identified weaknesses in the areas of pay, benefits, training, employee appreciation, COVID, and job satisfaction. The recommendations generated by this survey apply not only to water utilities in Kentucky but possibly to the water industry as a whole. [ABSTRACT FROM AUTHOR]

This paper describes the development of an optimal water quality tool for managing wet weather discharges that uses a macrolevel simulation model (i.e., the Streeter-Phelps equation) linked with a highly efficient optimization algorithm (i.e., a modified version of the Box complex method). The proposed approach can be applied to an urban watershed impaired by multiple sources of wet weather discharges. As an application, the proposed approach is used to develop optimal water quality management strategies for the Beargrass Creek watershed in Louisville, Ky. DOI: 10.1061/(ASCE)0733-9496(2009) 135:4(276) CE Database subject headings: Optimization; Computation; Mathematical models; Simulation models; Surface water; Watersheds.

This paper describes the use of inductive models developed using two artificial intelligence (AI)-based techniques for fecal coliform prediction and classification in surface waters. The two AI techniques used include artificial neural networks (ANNs) and a fixed functional set genetic algorithm (FFSGA) approach for function approximation. While ANNs have previously been used successfully for modeling water quality constituents, FFSGA is a relatively new technique of inductive model development. This paper will evaluate the efficacy of this technique for modeling indicator organism concentrations. In scenarios where process-based models cannot be developed and/or are not feasible, efficient and effective inductive models may be more suitable to provide quick and reasonably accurate predictions of indicator organism concentrations and associated water quality violations. The relative performance of M-based inductive models is compared with conventional regression models. When raw data are used in the development of the inductive models described in this paper, the AI models slightly outperform the traditional regression models. However, when log transformed data are used, all inductive models show comparable performance. While the work validates the strength of simple regression models, it also validated FFSGA to be an effective technique that competes well with other state-of-the-art and complex techniques such as ANNs. FFSGA comes with the added advantage of resulting in a simple, easy to use, and compact functional form of the model sought. This work adds to the limited amount of research on the use of data-driven modeling methods for indicator organisms. DOI: 10.1061/(ASCE)0733-9372(2008) 134:9(789) CE Database subject headings: Artificial intelligence; Neural networks; Computation; Pathogens; Regression models; Surface waters; Watersheds; Predictions.

This paper presents a methodology for developing total maximum daily loads (TMDLs) for pH impaired streams that characterizes the pH impact in terms of an associated hydrogen ion load. Because pH and an equivalent ion load can be related as a function of discharge and ionic strength, a functional relationship can be developed between discharge and the associated ion loading for a given pH value. By specifying a minimum pH value (e.g., 6.0) and an associated ion activity correction factor, an envelope of ion loads may be obtained as a function of discharge. By identifying a critical discharge for a given watershed, the hydrogen ion load and associated TMDL can be obtained. Determination of the associated ion load reduction can further be accomplished by developing functional relationships between measured discharges and measured ion loads for a given watershed. Finally, the required mass loading of an associated neutralizing agent (e.g. CaC[O.sub.3]) can be determined by constructing a functional relationship between the neutralizing agent and the required hydrogen ion reduction. The proposed approach has been applied to several watersheds in the state of Kentucky and was recently approved by EPA Region IV as an acceptable protocol for pH TMDLs. An application of the methodology is presented for the Beech Creek watershed, which is located in Muhlenberg County, Kentucky. DOI: 10.1061/(ASCE)0733-9372(2004)130:2(167) CE Database subject headings: Watersheds; Streams; Kentucky; Water pollution; Pollutants.

A nonlinear heuristic is developed for use in obtaining least-cost pump-operation policies for multisource, multitank water-distribution systems. The proposed algorithm links a minimum-cost-constraint identification methodology with a network-simulation model in order to provide the resulting policy. The algorithm has the advantage of being computationally efficient while incorporating the nonlinear characteristics of the water-distribution network. In addition, the algorithm has the added advantage of providing several feasible solutions to the control problem, which then provides the system operator with increased flexibility in selecting a particular policy.

The requirements and basic components of a typical optimal control environment for water-supply pumping systems are presented and discussed. Examined model components include hydraulic network models, demand forecast models, and optimal control models. A review of existing optimal control methodologies for water-supply pumping systems is also provided. Examined methodologies are classified on the basis of the type of system to which the methodology can be applied (single source - single tank or multiple source - multiple tank), the type of hydraulic model used (mass balance, regression, or hydraulic simulation), the type of demand model used (distributed or proportional), the type of optimization method used (linear programming, dynamic programming, or nonlinear programming), and the nature of the resulting control policy (implicit or explicit). Advantages and disadvantages of each approach are presented, along with recommendations for future work. The applicability of current technology to an existing water-supply pumping system is examined in light of existing technical limitations and operator acceptance issues.

The NIEHS-sponsored Appalachian Health & Well-Being Community Forum held in Eastern Kentucky brought various community members together to communicate and establish better coordination of efforts to improve health and address regional environmental issues. The 2-hour forum discussion provided bi-directional feedback about the needs and interests of community members. Top concerns of community members included obesity and obesity-related diseases and environmental pollution. Healthful lifestyles were identified as part of the remedy to protect health from potential adverse health effects associated with environmental pollution. This study highlights opportunities to engage with Appalachian communities around topics related to health and environmental pollution. [ABSTRACT FROM AUTHOR]

A network design based on the flow uniformity in various pipes improves the reliability of the network. One way to obtain such a flow distribution is by minimizing the variance of pipe flows. The available analytical method is critically studied, and observed to fail in providing global minimum variance of flow series. The analytical method accounts for the flow directions, while a variance evaluation requires that only the magnitude of flows is considered. A general nonlinear programming approach is tried, and it is observed that it requires correct knowledge of the flow direction. This article presents a genetic algorithm-based method to avoid this limitation. A linear programming-based algorithm is then suggested for selecting the optimal pipe sizes considering reliability. The proposed method is found to provide better design solutions than those obtained using some of the methodologies previously suggested for expansion of a water main system. [ABSTRACT FROM AUTHOR]