Omaha, NE, United States
Omaha, NE, United States

Time filter

Source Type

Cecconi M.,University of Perugia | Pane V.,University of Perugia | Napoli P.,Environmental Engineer | Cattoni E.,Biomedical University of Rome
Electronic Journal of Geotechnical Engineering | Year: 2012

Slope vegetation is currently finding wide applications all over the world to mitigate erosive phenomena and improve slope stability. An innovative natural technology for slope protection has been recently developed in Italy; this uses only natural perennial grass plants with deep roots and allows operating in areas where climatic conditions were, until a few years ago, considered prohibitive for the development of vegetation. Such technology appears promising with regard to shallow slope instability; the plant roots induce mechanical and hydraulic effects on slope equilibrium, which typically increase the soil shear strength. The mechanical effects of vegetation result from the root/soil interaction processes, while the hydraulic effects derive from the significant reduction of water content enhanced by plant transpiration. The quantitative evaluation of the mechanical effect has been modelled and implemented in a computing algorithm. © 2012 ejge.


De Feo G.,University of Salerno | De Gisi S.,Environmental Engineer
Water Science and Technology: Water Supply | Year: 2013

The aim of this paper is to study the treatment process of a Roman fullery ( fullonica) with particular attention to the water and wastewater management system. Remains of several fullonicae have been documented at Pompeii and Herculaneum (Campania, Southern Italy), Ostia and Rome (Latium region, Central Italy), Florence (Tuscany, Central Italy), etc. The common academic perception of Roman fullonicae is significantly influenced by the fullonica of Stephanus (I 6, 7) in Pompeii, which is assumed to be a paradigmatic case study in this paper. The use of urine as an alkaline chemical agent in the soaping phase of the filling treatment process was overstated, with there also being no evidence of the fact that fullers collected their urine by means of vessels in front of their workshops, as usually reported. Thus, it is not clear how the Roman fullers collected and transported the urine they used in the fulleries. Finally, the rinsing phase can be considered a clear example of water reuse. © IWA Publishing 2013.


von Stackelberg N.O.,Environmental Engineer | Neilson B.T.,Utah State University
Journal of Water Resources Planning and Management | Year: 2014

Stakeholder involvement in watershed management decisions remains challenging, particularly when one is relying upon modeling efforts as one of the primary means to understand and communicate the complicated processes controlling a natural riverine system. To determine how to meet the instream water quality standards as required by the total maximum daily load (TMDL) program, a QUAL2Kw water quality model was developed and calibrated for the Jordan River, Utah. To improve transparency, increase stakeholder engagement, and reach agreement more effectively, a collaborative approach was taken to calibrate the model that included Utah Division of Water Quality (UDWQ) staff, consultants, key stakeholder representatives, and independent experts. The study reach of the Jordan River flows 83 km from Utah Lake to the Great Salt Lake through the urbanized Salt Lake Valley in Utah. Several segments of the river have been listed by UDWQ as impaired for a number of constituents, but the present effort focuses on the dissolved oxygen (DO) impairment. In cooperation with stakeholder groups, four seasonal synoptic sampling surveys and additional research studies were conducted for use in calibrating and validating the model. The collaborative calibration process involved many meetings and workshops where model performance was iteratively evaluated in order to reach consensus on model inputs and parameterization. The end result of the collaborative calibration of the QUAL2Kw model was the development of a scientifically defensible tool used to establish a consensus that decomposition of organic matter and poor reaeration are the primary causes of the DO impairment in the Jordan River. Without the collaborative approach to calibration, agreement regarding the causes of water quality impairments would not likely have occurred. While clearly improving stakeholder believability in the model, a comparison of the collaborative calibration model performance to an autocalibrated version demonstrated that both approaches resulted in similar predictive accuracy. © 2014 American Society of Civil Engineers.


Stewart B.A.,Tetra Tech Inc. | New C.W.,Environmental Engineer | Hosni A.A.,Water Science Technologies | Dvorak B.I.,University of Nebraska - Lincoln
Journal of Environmental Engineering (United States) | Year: 2013

This study evaluated the system performance in terms of sorbent usage rate (SUR) of single column, two-column parallel, and lead-lag configurations, both with and without bypass blending, based on two normalized parameters describing the breakthrough profile (mass transfer zone length to lag ratio, or MTZ:Lag) and treatment objective (C/Co). The pore surface diffusion model was used to simulate a range of single compound scenarios to develop a framework for comparing configurations. From this analysis, regions on a MTZ:Lag versus C/Co plot could be identified in which particular configurations yielded the lowest system SUR. At low MTZ:Lag ratios, bypass blending (single column or lead-lag operation) offered significant improvements because of the ability to bypass untreated flow and reduce sorbent bed mass. However, at low target C/Co values, bypass offered little improvement. Lead-lag without bypass performed best at high MTZ:Lag ratios by passing the mass transfer zone through two columns in series. At high MTZ:Lag ratios and high target C/Co values, two-column parallel configurations yielded significant benefits by blending high and low concentration effluents and improving sorbent utilization. © 2013 American Society of Civil Engineers.


Mujiburrehman K.,Environmental Engineer
Water and Energy International | Year: 2014

The advent of satellite-based elevation dataset acquired by Shuttle Radar Topography Mission (SRTM) made new and novel techniques possible to model hydrological process in midsize to large scale watersheds. This application is important in regions with poor photogrammetric coverage and land use in appropriate scale like Mumbai. Watershed parameters include slope, area, perimeters and mean elevation are derived from SRTM dataset. SRTM-DEM (digital elevation model) can be used for extracting watershed parameters with a reasonable degree of accuracy. In this study, drainage analysis will be performed on a terrain model for Mumbai area draining into Mithi River. The Arc Hydro tool and HecGeoHMS extension into ArcMap 10.1 are used to derive several data sets that collectivity describe the drainage patterns of the Mithi River catchment. Raster analysis is performed to generate data on flow direction, flow accumulation, stream definition, stream segmentation, and watershed delineation. These data are then used to develop a vector representation of catchments and drainage lines from selected points. The utility of Arc Hydro tools is used to develop attributes that can be useful in hydrologic modeling. The main data is the DEM with 3 arcs second to get as much accurate results as could. The obtained catchment of Mithi River is verified with Google earth. The obtained river and its tributaries are found to be matching with Google earth. © 2014, Central Board of Irrigation and Power. All rights reserved.


Guner Y.,Environmental Engineer | Kayhan F.E.,Marmara University | Balkis N.,Istanbul University | Aksu A.,Istanbul University | Kaymak G.,Sakarya University
Pakistan Journal of Zoology | Year: 2016

The aim of this study was to determe cadmium and lead concentrations in the whole soft tissue of the black mussels (Mytilus galloprovincialis Lamarck, 1819) (n=60) caught from Pendik district coasts of Istanbul, Turkey. According to legal standards of Turkish Food Codex (TFC) and United Nations Environment Programme (UNEP) standards the level of Cd was low white that of Pb was high. The highest Pb concentration found in the whole soft tissue of mussels at S4 was 8.66 (February), 6.64 (January), 4.72 ppm Pb (July 2011) whereas in S5 it is 8.66 (November), 8.14 (February), 6.64 (October), 4.57 ppm (June 2012). Copyright 2016 Zoological Society of Pakistan.


Mimouni A.,Degremont | Kuzmyak N.,Environmental Engineer | Oort E.V.,University of Texas at Austin | Sharma M.,University of Texas at Austin | Katz L.,University of Texas at Austin
World Environmental and Water Resources Congress 2015: Floods, Droughts, and Ecosystems - Proceedings of the 2015 World Environmental and Water Resources Congress | Year: 2015

One of the main challenges in the reuse of flowback and produced water in slickwater hydraulic fracturing is the compatibility between additives and high total dissolved solids (TDS) concentrations, which are the most difficult contaminants to remove. Typical polyacrylamide friction reducers show reduced effectiveness in water with high ionic content, so water must either be treated or diluted with freshwater to reduce salt content before reuse. The case for directly reusing produced water with high salt content is presented in this research. The first part of the study ascertains the effectiveness of various friction reducers in brines. While typical polyacrylamide friction reducers lose their efficacy at high salt concentrations, we have identified other polymers that are generally resistant to changes in salt concentration. The second part of the research assesses not only the effect of pumping high-TDS water into a formation, but also the impacts of salt-tolerant friction reducers on shale stability and fracture conductivity. Shale compatibility experiments determined that injecting water with a higher salinity into a water-sensitive formation can benefit shale stability. In addition, the friction reducing agents were shown to have secondary stabilizing effects on shale. © 2015 ASCE.


Walker W.W.,Environmental Engineer | Kadlec R.H.,Chelsea Management
Critical Reviews in Environmental Science and Technology | Year: 2011

Longitudinal gradients in phosphorus (P) stored in the water column, vegetation, and soils develop in the wetlands where inflow P concentrations exceed background levels. Before the mid 1990's, the Everglades regional P gradient ranged from 100-200 mg L -1 in marsh inflows to background levels of 4-8 mg L -1. Subsequent implementation of P controls, including agricultural Best Management Practices and Stormwater Treatment Areas (STAs), has reduced the average inflow concentration along the northern edge of the Water Conservations Areas to approximately 30-50 mg L -1. Additional P controls are being implemented and further measures beyond those currently planned will be required to restore the entire marsh. The authors describe the evolution and application of relatively simple mass-balance models to simulate P storage and cycling processes along P gradients in the STAs and marsh. The models are practical tools with historical and future applications to designing P control measures involving source controls, water management, reservoirs, and STAs, as well as forecasting marsh responses to implementation of those control measures. Copyright © 2011 Taylor & Francis Group, LLC.


Pitta B.E.,Environmental Engineer | Palmer R.N.,University of Massachusetts Amherst
World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress | Year: 2011

Reservoir development on the Connecticut River Basin has altered the natural hydrograph and detrimentally affected the region's aquatic ecosystems that thrive on natural variability. This paper examines ways in which flows in the river and its tributaries can be returned to a more natural regime without negatively impacting other users. The analysis offers alternative operations to meet various objectives as well as evaluates the impacts of climate change on the basin. This paper focuses on the upper third of the basin as a proof of concept to demonstrate the decision support system and to generate initial results for the larger effort. © 2011 ASCE.


McAllister C.D.,Southeast Missouri State University | Ortiz A.Y.,Southeast Missouri State University | Southards T.J.,Environmental Engineer
Proceedings of the Institution of Civil Engineers: Water Management | Year: 2015

This study examines the ability of in-service domestic wastewater treatment facilities, as opposed to controllable laboratory experiments, to remove ammonia utilising recirculating sand filters (RSFs). Permitted facilities in Missouri, USA, are required to regularly sample, analyse and report discharged water quality. The Missouri Department of Natural Resources stores the results in a central database, which was queried and analysed to assess the performance of these facilities in both the summer and winter seasons and to determine if a correlation exists between ammonia removal and flow capacity. The RSFs were found to discharge ammonia under 44 mg/l 95% of the time in winter and under 30 mg/l in summer. No correlation between performance and flow was found. The results of the study suggest that RSF technology is presently unable to treat ammonia in domestic wastewater to meet acceptable water quality standards for surface discharge. ©.ICE Publishing: All rights reserved.

Loading Environmental Engineer collaborators
Loading Environmental Engineer collaborators