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Li Z.,Carbon Capture Scientific | Buchberger S.G.,University of Cincinnati | Clark R.M.,Environmental Engineering and Public Health Consultant | Jeffrey Yang Y.,U.S. Environmental Protection Agency | Swertfeger J.,Greater Cincinnati Water Works
Journal - American Water Works Association

Full-scale field measurement and rapid small-scale column test data from the Greater Cincinnati (Ohio) Water Works (GCWW) were used to calibrate and investigate the application of the logistic model for simulating breakthrough of total organic carbon (TOC) in granular activated carbon (GAC) contactors. The logistic model parameters were estimated using a nonlinear regression algorithm. The calibrated logistic model was validated using data from multiple GAC contactors operating in parallel at the GCWW Richard Miller Treatment Plant. This facility has experienced large seasonal variations in flow rate and TOC influent concentration. Proper estimation of logistic model parameters depends on the run-time length of the GAC breakthrough data set. A critical minimum runtime threshold must be achieved to produce reliable parameter estimates. A properly calibrated logistic model provides an effective tool for accurately simulating the blended TOC concentrations in the GAC contactor effluent at a municipal drinking water treatment plant. © 2012 American Water Works Association. Source

Herrick R.L.,University of Cincinnati | Buchberger S.G.,University of Cincinnati | Clark R.M.,Environmental Engineering and Public Health Consultant | Kupferle M.,University of Cincinnati | And 2 more authors.
Health Economics (United Kingdom)

Approximately 690 000-1 790 000 Salmonella cases, 20 000 hospitalizations, and 400 deaths occur in the USA annually, costing approximately $2.6bn. Existing models estimate morbidity, mortality, and cost solely from incidence. They do not estimate illness duration or use time as an independent cost predictor. Existing models may underestimate physician visits, hospitalizations, deaths, and associated costs. We developed a Markov chain Monte Carlo model to estimate illness duration, physician/emergency room visits, inpatient hospitalizations, mortality, and resultant costs for a given Salmonella incidence. Interested parties include society, third-party payers, health providers, federal, state and local governments, businesses, and individual patients and their families. The marginal approach estimates individual disease behavior for every patient, explicitly estimates disease duration and calculates separate time-dependent costs. The aggregate approach is a Markov equivalent of the existing models; it assumes average disease behavior and cost for a given morbidity/mortality. Transition probabilities were drawn from a meta-analysis of 53 Salmonella studies. Both approaches were tested using the 1993 Salmonella typhimurium outbreak in Gideon, Missouri. This protocol can be applied to estimate morbidity, mortality and cost of specific outbreaks, provide better national Salmonella burden estimates, and estimate the benefits of reducing Salmonella risk. Copyright © 2011 John Wiley & Sons, Ltd. Source

Clark R.M.,Environmental Engineering and Public Health Consultant | Li Z.,University of Cincinnati | Buchberger S.G.,University of Cincinnati
Frontiers of Earth Science

It is anticipated that global climate change will adversely impact source water quality in many areas of the United States and will therefore, potentially, impact the design and operation of current and future water treatment systems. The USEPA has initiated an effort called the Water Resources Adaptation Program (WRAP) which is intended to develop tools and techniques that can assess the impact of global climate change on urban drinking water and wastewater infrastructure. A three step approach for assessing climate change impacts on water treatment operation and design is being persude in this effort. The first step is the stochastic characterization of source water quality, the second step is the application of the USEPA Water Treatment Plant model and the third step is the application of cost algorithms to provide a metric that can be used to assess the coat impact of climate change. A model has been validated using data collected from Cincinnati's Richard Miller Water Treatment Plant for the USEPA Information Collection Rule (ICR) database. An analysis of the water treatment processes in response to assumed perturbations in raw water quality identified TOC, pH, and bromide as the three most important parameters affecting performance of the Miller WTP. The Miller Plant was simulated using the EPA WTP model to examine the impact of these parameters on selected regulated water quality parameters. Uncertainty in influent water quality was analyzed to estimate the risk of violating drinking water maximum contaminant levels (MCLs). Water quality changes in the Ohio River were projected for 2050 using Monte Carlo simulation and the WTP model was used to evaluate the effects of water quality changes on design and operation. Results indicate that the existing Miller WTP might not meet Safe Drinking Water Act MCL requirements for certain extreme future conditions. However, it was found that the risk of MCL violations under future conditions could be controlled by enhancing existing WTP design and operation or by process retrofitting and modification. © 2011 Higher Education Press and Springer-Verlag Berlin Heidelberg. Source

Clark R.M.,Environmental Engineering and Public Health Consultant | Thurnau R.C.,Eastern Research Group
14th Water Distribution Systems Analysis Conference 2012, WDSA 2012

Condition Assessment (CA) modeling is drawing increasing interest as a technique that can assist in managing drinking water infrastructure. This paper presents a model based on the use of a Cox Proportional Hazard (PH) approach modified by shared frailty and applies it to the drinking water network of the Laramie Water Utility (located in Laramie, Wyoming (USA) ). Using this model a cost/benefit analysis incorporating the Inspection Value Method (IVM), is used to assist in making improved repair, replacement and rehabilitation decisions for drinking water distribution system pipes. A separate analysis was conducted using a national data base model focused on prestressed concrete cylinder pipe (PCCP). Various currently available inspection technologies are presented and discussed. Copyright © (2012) by Engineers Australia. Source

Clark R.M.,Environmental Engineering and Public Health Consultant
World Environmental and Water Resources Congress 2015: Floods, Droughts, and Ecosystems - Proceedings of the 2015 World Environmental and Water Resources Congress

Even though drinking water hydraulic and water quality models are a recent development in the water industry, they have become widely used by both large and small utilities. The U.S. Environmental Protection Agency (US EPA) played a major role in the development of hydraulic/water quality modeling techniques and they have become embedded in the US Safe Drinking Water Act (SDWA). A key factor in encouraging the development of hydraulic/water quality modeling was the decision by the US EPA that drinking water standards promulgated under the SDWA of 1974 would apply at the consumers tap. The SDWA also requires that the cost of meeting standards at the tap must be considered. After passage of the SDWA (1974), and based on mandates contained in the Act, the US EPA began a systematic research effort that carefully examined the factors affecting the cost and quality of treated drinking water as it is transported through a pipe network. Research included theoretical analysis, mathematical modeling and field studies and lasted more than 20 years eventually leading to the development of EPANET. An early decision made during the development of EPANET was to make it open-source software and as a consequence, it has provided the basis for many research projects and studies including numerous graduate dissertations throughout the world. It has also provided the foundation for most of the proprietary models in use by the industry today including the quasi-public model PipeLine Net. In Fiscal year 2013 the US EPA recorded over 66,000 downloads of the software. © 2015 ASCE. Source

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