Solar photodegradation of dichloroacetic acid and 2,4-dichlorophenol using an enhanced photo-Fenton process

The photo-Fenton process using potassium ferrioxalate as a mediator was investigated for the photodegradation of dichloracetic acid (DCA) and 2,4-dichlorophenol (DCP) in aqueous medium using solar light as source of irradiation. The influence of the solution depth, the light intensity and the effect of stirring the solution during irradiation process were evaluated using DCA as a model compound. A negligible influence of stirring the solution was observed when the concentration of ferrioxalate (FeOx) was 0.8 mM and solution depth was 4.5 or 14 cm. The optimum FeOx concentration determined for solution depths between 4.5 and 14 cm was 0.8 mM considering total organic carbon (TOC) removal during DCA irradiation. The high efficiency of the photo-Fenton process was demonstrated on summer days, when only 10 min of exposition (around noon) were sufficient to completely destroy the organic carbon of a 1.0 mM DCA solution in the presence of 0.8 mM FeOx and 6.0 mM H2O2 using a solution depth of 4.5 cm. It was observed that the photodegradation efficiency increases linearly with the solar light intensity up to values around 15 Wm(-2) but this linear relationship does not hold above this value showing a square root dependence. The photodegradation of a solution of DCP/FeOx showed a lower TOC removal rate than that observed for DCA/FeOx, achieving approximately 90% after 35 min irradiation under 19 W m(-2), while under this light intensity, the same TOC removal of DCA/FeOx was achieved in only 10 min irradiation.     

Comparison between EMINENT and other energy technology assessment tools

Currently, issues related with climate change, security of energy supply, energy efficiency and sustainability are at the core of all energy policies and strategies. The current technologies are not able to face this challenge; therefore, the development of new and more sustainable energy technologies must be supported.As part of this, energy technology assessment tools can help decision-makers in the identification and evaluation of sustainable energy solutions, in order to integrate them in long term energy strategies.The EMINENT tool was developed to assess the performance and market potential of early stage technologies (EST) in a pre-defined energy chain, under national conditions, in terms of financial, energy and environmental criteria.This paper presents a comparative study between EMINENT and other tools for energy technology assessment. The tools analysed were CO2DB, MARKAL, IKARUS and E3Database.Although there are many different energy technology assessment tools, EMINENT seems to be the only one targeting EST.     

Modeling human exposures to air pollution control (APC) residues released from landfills in England and Wales

Human exposures to air pollution control (APC) residues released from 6 landfills were modeled and assessed. Following a qualitative risk characterisation, direct and indirect exposures were quantified. Site-specific air dispersion modeling was conducted for PM(10), PCDDs/PCDFs, Pb, Cd, As and Cr(VI) concentrations at the closest residential points of exposure for 4 landfill sites accepting, in total, 75% w/w of the APC residues disposed of in 2000-2001 (UK). Inhalation risks, assessed by reference to air quality standards at residential exposure points, were assessed as insignificant. Preliminary modeling suggested that indirect exposures from PCDDs/PCDFs at the 95th percentile level for the site where APC deposition rates were highest could potentially exceed the tolerable daily soil intake (TDSI) but this warrants further study given the model limitations. These results offer an initial screen of the significance of potential risks from APC disposal, which is of value in addressing concerns about the uncertainty of potential risks to human health from bulk APC disposal at strategic locations.     

Prediction of temperature and thermal inertia effect in the maturation stage and stockpiling of a large composting mass

A macroscopic non-steady state energy balance was developed and solved for a composting pile of source-selected organic fraction of municipal solid waste during the maturation stage (13,500 kg of compost). Simulated temperature profiles correlated well with temperature experimental data (ranging from 50 to 70 degrees C) obtained during the maturation process for more than 50 days at full scale. Thermal inertia effect usually found in composting plants and associated to the stockpiling of large composting masses could be predicted by means of this simplified energy balance, which takes into account terms of convective, conductive and radiation heat dissipation. Heat losses in a large composting mass are not significant due to the similar temperatures found at the surroundings and at the surface of the pile (ranging from 15 to 40 degrees C). In contrast, thermophilic temperature in the core of the pile was maintained during the whole maturation process. Heat generation was estimated with the static respiration index, a parameter that is typically used to monitor the biological activity and stability of composting processes. In this study, the static respiration index is presented as a parameter to estimate the metabolic heat that can be generated according to the biodegradable organic matter content of a compost sample, which can be useful in predicting the temperature of the composting process.     

Reference values for acetyl and butyrylcholinesterases in cattle under actual management conditions,hepatic and renal function by application of chlorpyrifos

Chlorpyrifos is an anticholinesterase organophosphate insecticide widely used in Argentina in the production of food derived from animal, fruit and horticultural origin and is reported as a residue within these products. Local reference values for acetyl and butyrylcholinesterase were determined in Aberdeen Angus bovine and cross bred cattle (n = 25), a requirement to be able to evaluate toxicity of commercial organophosphate and carbamate formulations. The activity of cholinesterase enzymes presented an overall mean of 2,183.00 ± 485.6 IU L^?1 for erythrocyte acetylcholinesterase and 203.1 ± 42.06 IU L^?1 for plasma butyrylcholinesterase, which are used as reference values for meat steers within a system of intensive production in a semi-arid region. The toxic potential of chlorpyrifos in steers of the same breeds (n = 12) was assessed applying chlorpyrifos 15.00% Tipertox® in a single therapeutic dose of 7.50 mg kg^?1 by topical route. Prior to application and then on day 1 and day 21 post-application, both blood cholinesterases, serum chlorpyrifos concentration by ultra-high resolution liquid chromatography with mass detector, analysis of blood counts, total proteins, liver enzymes, urea and creatinine were evaluated. The mean plasma concentration of chlorpyrifos was 27.90 ug L^?1 at 24 h. The findings indicate that the therapeutic treatment of castrated male bovines treated with chlorpyrifos, applied by pour-on according to the manufacturer's instructions, does not cause changes in the variables evaluated.     

Spatial modeling of factor analysis scores

The use of mosses as biomonitors operates as an indicator of their concentration in the environment, becoming a methodology which provides a significant interpretation in terms of environmental quality. The different types of pollution are variables that can not be measured directly in the environment - latent variables. Therefore, we propose the use of factor analysis to estimate these variables in order to use them for spatial modelling. On the contrary, the main aim of the commonly used principal components analysis method is to explain the variability of observed variables and it does not permit to explicitly identify the different types of environmental contamination. We propose to model the concentration of each heavy metal as a linear combination of its main sources of pollution, similar to the case of multiple regression where these latent variables are identified as covariates, though these not being observed. Moreover, through the use of geostatistical methodologies, we suggest to obtain maps of predicted values for the different sources of pollution. With this, we summarize the information acquired from the concentration measurements of the various heavy metals, and make possible to easily determine the locations that suffer from a particular source of pollution.     

Sediments as a potential tool for assessment of sewage pollution in Barigüi River, Brazil

Sediments constitute a pollutant trap and have proven to be an efficient tool to identify environmental impacts. Sediments are considered a very important means to assess the level of contamination of water bodies because of their ability to accumulate metals and organic. The anthropogenic inputs of sewage, with or without prior treatment, in aquatic environments, affect the geochemical composition of sediment. In addition, the sediment adsorbs hydrophobic compounds found in feces, such as the fecal sterols. The granulometric and geochemical composition of the sediment of Barigüi River-Brazil was investigated. The results show that silt and clay dominate the granulometric composition of the sediments. The geochemical composition of sediments showed high concentrations of phosphorus and nitrogen. The Redfield ratios confirm the inputs of phosphorus and nitrogen. The TOC/N ratio was used to identify the source of pollution. N/TP ratios were found between 1.0 and 3.5. Clearly, an input of phosphorus, sewage is the most acceptable source, following the historic profile of the Barigüi River. High concentration of nitrogen phosphorus labels the area to be polluted by sewage. To confirm the sewage pollution, adsorbed fecal sterols in sediments were investigated. The concentration of total sterols was found between 0.86 and 304.58 μg g^???1. Two distinguished scenario was found, one severely polluted and another slightly polluted. The highest concentrations of total fecal sterols were associated with sediment whose geochemical composition showed higher levels of TOC, as well as higher proportions of silt and clay. Also, epicoprostanol, a coprostanol isomer, was used as an indicator of the level of treatment or age of the fecal matter because it is formed during the treatment of wastewater and sludge digestion. If the treatment of sludge takes a long time, epicoprostanol can form from cholesterol, and relative proportions of those compounds may be used as an indicator of the presence of untreated sewage in the sediments. The epicoprostanol was found in the range between 0.02 and 9.71 μg g^???1; concentration of up to 0.015 μg g^???1 represents situations where there is strong contamination by sewage. All sites investigated showed a concentration of epicoprostanol higher than the value adopted as threshold. The lower concentration of epicoprostanol found for all sites is consistent with the high concentration found for coprostanol, and this is typical for untreated sewage.