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Jiang D.,University of Connecticut | Curtis M.,Fuss and oNeill Inc. | Troop E.,Fuss and oNeill Inc. | Scheible K.,Hydroqual Inc | And 5 more authors.
International Journal of Hydrogen Energy | Year: 2011

A new type of microbial fuel cell (MFC), multi-anode/cathode MFC (termed as MAC MFC) containing 12 anodes/cathodes were developed to harvest electric power treating domestic wastewater. The power density of MAC MFCs increased from 300 to 380 mW/m2 at the range of the organic loading rates (0.19-0.66 kg/m3/day). MAC MFCs achieved 80% of contaminant removal at the hydraulic retention time (HRT) of 20 h but the contaminant removal deceased to 66% at the HRT of 5 h. In addition, metal-doped manganese dioxide (MnO 2) cathodes were developed to replace the costly platinum cathodes, and exhibited high power density. Cu-MnO2 cathodes produced 465 mW/m2 and Co-MnO2 cathodes produced 500 mW/m2. Due to the cathode fouling of the precipitation of calcium and sodium, a decrease in the power density (from 400 to 150 mW/m2) and an increase in internal resistance (Rin) (from 175 to 225 ) were observed in MAC MFCs. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

Zhang W.,Wuhan University | Wang Y.,Wuhan University | Peng H.,Wuhan University | Li Y.,Wuhan University | And 2 more authors.
Water Resources Management | Year: 2010

As the demand for water continuously increases with population growth and economic development, the gap between water supply and demand in China has become increasingly wide. In recent years worsening water pollution has caused this gap to become much more serious. Conventional allocation pattern, which mainly considers water quantity as the key factor, is no longer satisfying the water allocation need. A coupled water quantity-quality model in a river basin is presented in this paper to provide a tool for water allocation schemes analysis. The pollutants transport and hydrological cycling processes in a river basin are involved in the model. A river network is divided into different reaches. According to the division of river network, the areas out of the river are divided into a series of tanks. In each tank, hydrologic processes, pollutant loading production, water demand of users and water supply are calculated. In river network, hydrodynamics processes and water quality are simulated. Water quantity and quality exchanges between each tank and river are also considered. The time step of water quality calculation is 24 h, the same with that of water quantity calculation. In each time step period, the connections of river reaches and tanks are realized through the exchange of water quantity and quality between rivers and tanks: pollutants discharge from tanks to rivers and water intake from rivers to satisfy water demand in tanks. The water use in each tank includes three types: domestic, industrial and agricultural water use. Water allocation schemes are one of the input conditions of the model. Using the proposed model, in each tank, water demand and deficit of different uses, in both water quantity and quality, can be obtained under different water allocation schemes. According to the water deficit, water allocation schemes are analyzed to make proper allocation schemes. In this aspect, the proposed model can also be thought as a water allocation model. The model is tested and applied to the Jiaojiang River basin, Zhejiang Province, China, to analyze the different water resource allocation schemes. © Springer Science+Business Media B.V. 2009.

England J.F.,Bureau of Reclamation | Julien P.Y.,Colorado State University | Velleux M.L.,Hydroqual Inc
Journal of Hydrology | Year: 2014

Traditionally, deterministic flood procedures such as the Probable Maximum Flood have been used for critical infrastructure design. Some Federal agencies now use hydrologic risk analysis to assess potential impacts of extreme events on existing structures such as large dams. Extreme flood hazard estimates and distributions are needed for these efforts, with very low annual exceedance probabilities (≤10 - 4) (return periods >10,000years). An integrated data-modeling hydrologic hazard framework for physically-based extreme flood hazard estimation is presented. Key elements include: (1) a physically-based runoff model (TREX) coupled with a stochastic storm transposition technique; (2) hydrometeorological information from radar and an extreme storm catalog; and (3) streamflow and paleoflood data for independently testing and refining runoff model predictions at internal locations. This new approach requires full integration of collaborative work in hydrometeorology, flood hydrology and paleoflood hydrology. An application on the 12,000km2 Arkansas River watershed in Colorado demonstrates that the size and location of extreme storms are critical factors in the analysis of basin-average rainfall frequency and flood peak distributions. Runoff model results are substantially improved by the availability and use of paleoflood nonexceedance data spanning the past 1000years at critical watershed locations. © 2013 .

Naddy R.B.,AECOM Technology Corporation | McNerney G.R.,AECOM Technology Corporation | Gorsuch J.W.,Gorsuch Environmental Management Services Inc. | Bell R.A.,McMaster University | And 3 more authors.
Ecotoxicology | Year: 2011

Acute silver toxicity studies were conducted with and without food for four common freshwater test species: Daphnia magna, Ceriodaphnia dubia, Pimephales promelas (fathead minnow-FHM), and Oncorhynchus mykiss (rainbow trout-RBT) in order to generate acute-to-chronic ratios (ACR). The studies were conducted similarly (i.e., static-renewal or flow-through) to chronic/early-life stage studies that were previously performed in this laboratory. The acute toxicity (EC/LC50 values) of silver without food ranged from 0.57 μg dissolved Ag/l for C.dubia to 9.15 μg dissolved Ag/l for RBT. The presence of food resulted in an increase in EC/LC50 values from 1.25× for RBT to 22.4× for C. dubia. Invertebrate food type was also shown to effect acute silver toxicity. Food did not affect EC/LC50s or ACRs as greatly in fish studies as in invertebrate studies. ACRs for both invertebrate species were <1.0 when using acute studies without food but were 1.22 and 1.33 when using acute studies with food. ACRs for FHMs ranged from 4.06 to 7.19, while RBT ACRs ranged from 28.6 to 35.8 depending on whether food was present in acute studies. The data generated from this research program should be useful in re-determining a final ACR for silver in freshwater as well as in risk assessments. © 2011 Springer Science+Business Media, LLC.

Esbaugh A.J.,University of Miami | Esbaugh A.J.,University of Texas at Austin | Mager E.M.,University of Miami | Brix K.V.,University of Miami | And 2 more authors.
Aquatic Toxicology | Year: 2013

The toxicity of many metals is impacted by environmental pH, through both competition and complexation by hydroxide and carbonate ions. To establish safe environmental regulation it is important to properly define the relationship between pH and metal toxicity, a process that involves manipulating the pH of test water in the lab. The current study compares the effects of the three most common pH manipulation methods (carbon dioxide, acid-base addition, and chemical buffers) on acute Pb toxicity of a model fish species, Pimephales promelas. Acidification of test water revealed that the Pb and Pb2+ LC50 values were impacted by the pH manipulation method, with the following order of effects: HCl

Takamatsu M.,Hydroqual Inc | Barrett M.,University of Texas at Austin | Charbeneau R.J.,University of Texas at Austin
Journal of Environmental Engineering | Year: 2010

Treatment of storm-water runoff may be necessary before discharge to surface waters. In urban areas, space constraints limit selection of conventional treatment systems, and alternative systems are needed. This research program involves design and laboratory testing of a small footprint nonproprietary detention basin which consists of pipes and box culvert sections with a specialized inlet and outlet system. This system can be placed below grade near the roadway section as part of the conventional drainage system and does not require additional right-of-way. A mathematical model, based entirely on hydraulic principles, is developed to estimate particle removal efficiency of the rectangular detention basin for the treatment of storm-water runoff by extending ideal horizontal tank theory under the condition in which water level is varied. A physical model was built in 1/5 scale to measure particle removal performance and validates the conceptual model. Experiments were performed for steady inflow conditions with different inflow rates, durations, and suspended sediment concentrations. Measured time series outflow suspended sediment concentrations and particle removal efficiency compare well with calculated results from the conceptual model. The outflow particle-size distribution can also be estimated using the conceptual model. © 2010 ASCE.

Mager E.M.,University of Miami | Brix K.V.,University of Miami | Gerdes R.M.,Cold Spring Harbor Laboratories | Ryan A.C.,Hydroqual Inc | Grosell M.,University of Miami
Ecotoxicology and Environmental Safety | Year: 2011

As the first step toward parameterization of a chronic lead (Pb) biotic ligand model (BLM) for Ceriodaphnia dubia, 7-d toxicity tests were performed in waters modified to evaluate the influences of hardness, DOM (as Suwannee River NOM and Aldrich humic acid (HA)), pH (buffered with 4mM MOPS) and alkalinity on the chronic toxicity of Pb. Calculated EC20s for the control base water test and each of the most extreme modified test waters were as follows in γgL-1 Pb (95% confidence interval): base water control=45 (14-53), 5mM CaSO4=22 (12-30), 32mgL-1 DOM=523 (388-573), 2.5mM NaHCO3=73 (21-120) and pH 6.4 buffered with MOPS=3.9γgL-1 Pb (1-5). Results indicate that hardness does not protect against chronic toxicity of Pb to C. dubia, whereas HA does protect at the highest concentration tested (597γM). Additionally, our findings suggest that low pH increases the chronic toxicity of Pb whereas increased alkalinity is protective. The findings reported herein support the need for a chronic Pb BLM as an alternative approach to hardness-based regulations. © 2010 Elsevier Inc.

Isleib R.R.,Hydroqual Inc | Thuman A.J.,Hydroqual Inc
Watershed Management Conference 2010: Innovations in Watershed Management under Land Use and Climate Change - Proceedings of the 2010 Watershed Management Conference | Year: 2010

Lake Loiza and Lake La Plata are two impaired lakes located in Eastern Puerto Rico. Both lakes are impaired due to excessive phosphorus inputs from the surrounding watersheds with upstream river impairments due to fecal coliform. The goal of the Watershed Stewardship Program is to develop meaningful water quality improvement strategies for impaired waters in the Rio Grande de Loiza and Rio La Plata Watersheds tributary to and including Lakes Loiza and La Plata. Included in these location specific strategies is the identification of the water quality problems, identification of the sources of these problems, the development of water quality models to provide insight, and to develop remedies for these problems. During Phase 1 of the program, TMDLs were developed using the Loading Simulation Program in C++ (LSPC) model and existing data. The existing data were relatively sparse and unevenly distributed within the Loiza and La Plata watersheds. Phase 2 of the program involved identifying four small pilot subwatersheds that could be used to test the modeling assumptions of Phase 1 by collecting site specific data and developing Hydrologic Simulation Program - Fortran (HSPF) models for total phosphorus and fecal coliform. As LSPC and HSPF are "lumped parameter" models, they are useful for examining large scale watersheds and producing generalized results. Many of the large scale assumptions can break down when assessing smaller areas within the larger watershed. Overall the modeling analysis of the small subwatersheds verified the assumptions of the original TMDL analysis. However, certain loading assumptions, such as estimates of the percentage of failing septic systems, varied widely from one subwatershed to another. Management plans were also developed and implemented during Phase 2 of the Watershed Stewardship Program to improve water quality in each of the pilot subwatersheds based on the needs in each subwatershed. Post-implementation sampling is planned during 2010 to assess the effectiveness of the management plans. The intent is to use the pilot subwatershed management plans as a model for other watersheds within Puerto Rico. © 2011 ASCE.

Mager E.M.,University of Miami | Esbaugh A.J.,University of Miami | Brix K.V.,University of Miami | Ryan A.C.,Hydroqual Inc | Grosell M.,University of Miami
Comparative Biochemistry and Physiology - C Toxicology and Pharmacology | Year: 2011

The acute toxicity of lead (Pb) was examined for fathead minnows (Pimephales promelas; 96-h) and daphnids (Ceriodaphnia dubia; 48-h) in waters modified for hardness (as CaSO4), dissolved organic carbon (DOC; as Aldrich humic acid) and alkalinity (as NaHCO3) for parameterization of an acute freshwater biotic ligand model (BLM). Additionally, acute (96-h) and chronic (30-d) bioassays were performed for P. promelas to more clearly define the influence of pH (5.5-8.3) on Pb toxicity as modified by addition of HCl or NaOH using an automated titration system. Results indicate that Ca2+ is protective against acute Pb toxicity to P. promelas but not C. dubia. Strong protection was afforded by DOC and NaHCO3 against acute Pb toxicity to P. promelas, whereas milder protection was observed for C. dubia with both parameters. Dissolved Pb LC50s from the P. promelas pH bioassays revealed a complex effect of pH on Pb toxicity, likely explained in part by Pb speciation and the competitive interaction of H+ with ionic Pb2+. Chronic pH bioassays also demonstrated that 30-d growth is not impaired in fathead minnows at relevant Pb concentrations. The findings reported herein suggest that development of separate BLMs for P. promelas and C. dubia should be considered. © 2010 Elsevier Inc.

Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 149.88K | Year: 2010

This Small Business Innovation Research Phase I project will investigate a new enhanced filter media for decentralized water purification systems. Whereas implementation of ultraviolet (UV), membrane, or ozonation systems at water treatment facilities is capital-intensive and potentially infeasible for smaller plants, decentralized systems, such as point-of-use (POU) and point-of-entry (POE) devices, are treatment options that are relatively inexpensive and provide additional protection for consumers. Recent studies have shown that nanoparticles of the reactive element zero-valent iron (ZVI) can adsorb and inactivate viruses and other microbial pathogens in water. In this project, we will develop a process to create high-surface area coatings of nano-ZVI onto granular media to enable a superior POU filtration product. By incorporating this new material, we can significantly improve the ability of POU/POE devices to remove viruses, other microorganisms, and other contaminants (e.g. arsenic, lead, and disinfection byproducts) from drinking water. In Phase I, we will develop a process to coat nano-ZVI onto filtration media, characterize the media, and test the resulting filter with respect to key organic and inorganic contaminants. The broader impact/commercial potential of this project will be a new filter technology which will perform as well as, or better than, existing technologies (e.g., ultraviolet, reverse osmosis, and nanofiltration), but which is cheaper to manufacture. In 2005, the US market for household water treatment products was $2.6 billion, with the European market forecasted to reach $1 billion by the year 2014. Once successfully demonstrated, the proposed innovation will offer consumers with considerable benefits including reduced health risks and greater water supply security for homeowners and military personnel stationed in remote locations, enhanced portable water treatment capabilities for campers and field workers, and potential new job opportunities in the water treatment technology manufacturing industry. One of the major advantages of the proposed innovation is that it builds upon existing POU/POE technologies. It would, therefore, be familiar to customers and could be marketed as an ?improved? product.

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