Exergoeconomic and exergoenvironmental analyses of a combined cycle power plant with chemical looping technology

CO₂ capture and storage from energy conversion systems is one option for reducing power plant CO₂ emissions to the atmosphere and for limiting the impact of fossil-fuel use on climate change. Among existing technologies, chemical looping combustion (CLC), an oxy-fuel approach, appears to be one of the most promising techniques, providing straightforward CO₂ capture with low energy requirements.This paper provides an evaluation of CLC technology from an economic and environmental perspective by comparing it with to a reference plant, a combined cycle power plant that includes no CO₂ capture. Two exergy-based methods, the exergoeconomic and the exergoenvironmental analyses, are used to determine the economic and environmental impacts, respectively. The applied methods facilitate the iterative optimization of energy conversion systems and lead towards the improvement of the effectiveness of the overall plant while decreasing the cost and the environmental impact of the generated product. For the plant with CLC, a high increase in the cost of electricity is observed, while at the same time the environmental impact decreases.     

Evaluation of groundwater quality and its suitability for drinking,domestic, and agricultural uses in the Banana Plain (Mbanga,Njombe, Penja) of the Cameroon Volcanic Line

Groundwater quality of the Banana Plain (Mbanga, Njombe, Penja—Cameroon) was assessed for its suitability for drinking, domestic, and agricultural uses. A total of 67 groundwater samples were collected from open wells, springs, and boreholes. Samples were analyzed for physicochemical properties, major ions, and dissolved silica. In 95% of groundwater samples, calcium is the dominant cation, while sodium dominates in 5% of the samples. Eighty percent of the samples have HCO₃ as major anion, and in 20%, NO₃ is the major anion. Main water types in the study area are CaHCO₃, CaMgHCO₃, CaNaHCO₃, and CaNaNO₃ClHCO₃. CO₂-driven weathering of silicate minerals followed by cation exchange seemingly controls largely the concentrations of major ions in the groundwaters of this area. Nitrate, sulfate, and chloride concentrations strongly express the impact of anthropogenic activities (agriculture and domestic activities) on groundwater quality. Sixty-four percent of the waters have nitrate concentrations higher than the drinking water limit. Also limiting groundwater use for potable and domestic purposes are contents of Ca²⁺, Mg²⁺ and HCO₃ ⁻ and total hardness (TH) that exceed World Health Organization (WHO) standards. Irrigational suitability of groundwaters in the study area was also evaluated, and results show that all the samples are fit for irrigation. Groundwater quality in the Banana Plain is impeded by natural geology and anthropogenic activities, and proper groundwater management strategies are necessary to protect sustainably this valuable resource.     

Ecotoxicology of glyphosate and recent advances in its mitigation by adsorption

Environmental Science and Pollution Research - Glyphosate (N-[phosphonomethyl]glycine) is one of the most popular herbicides now used in agricultural practice. The aim of this paper was to discuss...     

Waste management options in southern Europe using field and experimental data

The applicability of the Waste Management Hierarchy concept that appeared to be an essential element in current national environmental policies was investigated in the case of a region in Southern Europe. The waste generation profile that determines the appropriateness of different waste management options was created after a 1-year municipal waste sampling investigation conducted in the Municipality of Pilea in Northern Greece. The paper describes the results of (1) the sampling method, which was conducted four times during 1 year (once per season) in selected areas of the city, (2) the qualitative analysis of the collected samples and (3) the waste treatment, which consisted of drying, grinding, calorific value measurement, incineration and chemical analysis of the collected samples. Comparative analysis between the above mentioned data and on past data derived from investigations conducted in other Greek regions with similar characteristics to those of Pilea were used to identify and discuss future trends in the composition of generated waste over time. An analysis of the current waste management status in Greece as well as the feasibility of implementing a comprehensive management approach is assessed taking into account guidelines set worldwide to promote renewable energy sources use. It is concluded that recycling, perhaps the most positively received of all waste management practices, is going to be an essential part of contemporary waste management strategies, composting can play an important role, while incineration seems to be a conditionally feasible solution.     

Modeling Hydrologic Benefits of Low Impact Development: A Distributed Hydrologic Model of The Woodlands,Texas

Low Impact Development (LID) is alternative design approach to land development that conserves and utilizes natural resources to minimize the potential negative environmental impacts of development, such as flooding. The Woodlands near Houston, Texas is one of the premier master‐planned communities in the United States. Unlike in a typical urban development where riparian corridors are often replaced with concrete channels, pervious surfaces, vegetation, and natural drainage pathways were preserved as much as possible during development. In addition, a number of detention ponds were strategically located to manage runoff on site. This article uses a unique distributed hydrologic model, Vflo?, combined with historical (1974) and recent (2008 and 2009) rainfall events to evaluate the long‐term effectiveness of The Woodlands natural drainage design as a stormwater management technique. This study analyzed the influence of LID in The Woodlands by comparing the hydrologic response of the watershed under undeveloped, developed, and highly urbanized conditions. The results show that The Woodlands drainage design successfully reflects predeveloped hydrologic conditions and produces peak flows two to three times lower than highly urbanized development. Furthermore, results indicate that the LID practices employed in The Woodlands successfully attenuate the peak flow from a 100‐year design event, resulting in flows comparable to undeveloped hydrologic conditions.     

McKusik-Kaufman syndrome: prenatal diagnosis,genetics and follow up

McKusick-Kaufman syndrome (MKKS) is a rare autosomal recessive genetic disease with classical hexadactyly and hydrocolpos in females and sometimes cardiac abnormality. We report such a case diagnosed just before birth with a favourable outcome. From this case we describe and discuss all the prenatal sonographic signs which are not always present. On the genetic side, the gene has recently been localized together with the mutation responsible for MKKS. The phenotypic relationship between MKKS which has a good prognosis and Bardet-Biedl syndrome (BBS) with a worse prognosis requires great caution before diagnosing MKKS and a long follow-up is necessary to recognize obesity, growth retardation and pigmentary retinitis. Copyright © 2002 John Wiley & Sons, Ltd.