Search results for "Environmental engineering"
showing 10 items of 2674 documents
Productivity growth of wastewater treatment plants – accounting for environmental impacts: a Malmquist-Luenberger index approach
2015
As the number of wastewater treatment plants (WWTPs) has increased, the economic considerations associated with their management have become more relevant. Measuring the productivity of WWTPs allows the best practice to be identified and resource use to be optimized. Previous studies assessing the productivity change of WWTPs have ignored undesirable outputs; thus, wastewater treatment was considered to be free of environmental impacts. To overcome this limitation and for the first time, we assessed the productivity growth of a sample of Spanish WWTPs, while also accounting for the emission of greenhouse gases and sludge production. The Malmquist-Luenberger productivity index (MLPI) and its…
Influence of greenhouse different coverings on chemical and physical risk factors
2005
Crop production in greenhouses needs the use of chemicals and requires high levels of temperature and relative humidity to assure the increasing of crop production. This can cause risks for the health of the operators, especially if they are not equipped with protection devices. The risks may also vary with the type and/or size and/or shape of the protected structures. In order to determine the influence of different coverings on type and amount of risks, chemical and physical risk factors were measured inside greenhouses with different cladding materials (glass panels and plastic films) after crop management. In these two different greenhouses typologies, that were similar for location and…
Sub-critical long-term operation of industrial scale hollow-fibre membranes in a submerged anaerobic MBR (HF-SAnMBR) system
2012
The aim of this study was to evaluate the long-term performance of hollow-fibre (HF) membranes used to treat urban wastewater in a submerged anaerobic MBR when operating sub-critically. To this end, a demonstration plant with two industrial scale HF ultrafiltration membrane modules was operated under different conditions. The main factor affecting membrane performance was the concentration of mixed liquor total solids (MLTS). The reversible fouling rate remained low even when MLTS levels (about 25 g L−1) in the membrane tank were high. No chemical cleaning was conducted whilst operating the plant for more than one year because no irreversible fouling problems were detected. The almost compl…
Occurrence of pesticide residues in Spanish beeswax
2017
Beeswax from Spain was collected during 2016 to determine pesticide residues incidence. The 35 samples were divided in foundation, old combs, cappings or virgin beeswax to compare pesticide content between groups. Wax was screened for 58 pesticides or their degradation products by QuEChERS extraction and liquid chromatography mass spectrometry (LC-MS/MS). Beeswax was uniformly contaminated with acaricides and, to a much lesser extent, with insecticide and fungicide residues. Virgin followed by cappings were less contaminated than foundation and old combs beeswax. The miticides applied in-hive had a contribution to average pesticide load higher than 95%. Compounds widely used as acaricides, …
Exposure and cumulative risk assessment to non-persistent pesticides in Spanish children using biomonitoring.
2020
Abstract The main objective of the present research is to evaluate the exposure to pesticides in children (n = 568) from the Valencian Region (Spain). Six non-specific and 20 specific metabolites of organophosphate pesticides (OPs), herbicides (Herb), and pyrethroids (Pyr) were analyzed in urine samples. The biomarkers with the highest detection frequencies (>70%) were diethyl phosphate, p-nitrophenol, 3-phenoxybenzoic acid, and 3,5,6-trichloro-2-pyridinol, whose geometric mean concentrations (ng·ml-n1) were 1.53, 1.03, 1.51 and 1.19, respectively. Robust regression models showed that the province of residence and the recent consumption of vegetables, legumes and cereals were some of the mo…
A two-year monitoring of pesticide hazard in-hive: High honey bee mortality rates during insecticide poisoning episodes in apiaries located near agri…
2019
Pesticide residues in beebread, live and dead honey bees, together with honey bee death rate were monitored from June 2016 to June 2018 in three apiaries, located near agricultural settings and in wildlands. Dead honey bees were only collected and analyzed when significant mortality episodes occurred and pesticide content in beeswax of each experimental apiary was evaluated at the beginning of the study. Samples were extracted by a modified QuEChERS procedure and screened for pesticides residues by liquid chromatography mass spectrometry (LC-MS/MS). Pesticide hazard in the samples was evaluated through the hazard quotient approach (HQ). Beebread was widely contaminated with coumaphos and am…
Chemical oxidation and reduction of hexachlorocyclohexanes: A review
2019
Abstract Lindane (γ-hexachlorocyclohexane) and its isomers (HCH) are some of the most common and most easily detected organochlorine pesticides in the environment. The widespread distribution of lindane is due to its use as an insecticide, accompanied by its persistence and bioaccumulation, whereas HCH were disposed of as waste in unmanaged landfills. Unfortunately, certain HCH (especially the most reactive ones: γ- and α-HCH) are harmful to the central nervous system and to reproductive and endocrine systems, therefore development of suitable remediation methods is needed to remove them from contaminated soil and water. This paper provides a short history of the use of lindane and a descri…
Photoelectrocatalyzed degradation of organophosphorus pesticide fenamiphos using WO3 nanorods as photoanode
2020
[EN] In this study, WO3 nanostructures were synthesized by the electrochemical anodization technique to use them on the degradation of persistent organic compounds such as the pesticide fenamiphos. The acids electrolyte used during the anodization were two different: 1.5 M H2SO4-0.05 M H2O2 and 1.5 M CH4O3S-0.05 M H2O2. Once the samples have been manufactured, they have been subjected to different tests to analyze the properties of the nanostructures. With Field Emission Scanning Electron Microscopy (FESEM) the samples have been examined morphologically, their composition and crystallinity has been studied through Raman Spectroscopy and their photoelectrochemical behaviour by Photoelectroch…
Gold-nanoparticles ingestion disrupts reproduction and development in the German cockroach.
2015
The present work shows the effects of gold nanoparticles (AuNPs) orally administered on reproduction and development of the insect Blattella germanica. Newly emerged females were provided with food containing AuNPs (87.44μg/g) of a size between 15 and 30nm (mean 21.8nm), and were allowed to mate with males. Food ingestion, mortality, reproductive parameters (time to ootheca formation and eclosion, ootheca viability and fertility) as well as postembryonic developmental parameters of the first ootheca (nymphal survival and life span) were recorded throughout the experiment. Gold from AuNPs was accumulated by adults of B. germanica with a bioaccumulation factor of 0.1. Ingestion of AuNPs did n…
A new potential toxaphene congener: synthesis, GC/EI-MS study, crystal structure, NMR analysis, and ab initio calculations of 3-endo,5-endo-dichloro-…
2001
Abstract A new potential toxaphene congener 3- endo ,5- endo -dichloro-7,7-bis-chloromethyl-4-dichloromethyl-tricyclo[2.2.1.0 2,6 ]heptane 2 has been isolated from reaction mixture obtained by the chlorination of 2- exo ,10,10-trichlorobornane 1 . The X-ray structural analysis of 2 revealed an unusual tricyclic structure, where the two chlorine atoms occupying endo -positions are in close spatial proximity with each other and near to the neighbouring CHCl 2 group. Further, it revealed that the symmetry of the molecule is distorted. The 1 H and 13 C NMR spectra of 2 have been assigned by means of 1 H, 1 H d ouble- q uantum f iltered co rrelation s pectroscop y (DQF COSY), PFG 1 H, 13 C HMQC …