Publications by authors named "Yolanda Fernandez-Nava"

Coke wastewater is a complex industrial wastewater due to its high content of toxic compounds such as cyanides, thiocyanates, phenols, tar, oils, and fats. After a series of treatments, wastewater with a high ammonium content is obtained (around 4,150 mg·L-1). A stripping process is used to reduce it.

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Due to the COVID-19 pandemic, lockdown restrictions were established around the world. Many studies have assessed whether these restrictions affected atmospheric pollution. Comparison between them is difficult as the periods of time considered are generally not the same and thus, different conclusions may be reached.

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There is growing interest in investigating the human health risk associated with metals in airborne particulate matter. The objective of this paper is the health risk assessment of Al, Be, Sb, Sn, Ti and Tl in PM under different advections of air masses. These metals/semi-metal were studied in samples collected in an area influenced by industrial activities in northern Spain with the aim of analysing the variations in PM metal/semi-metal.

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Article Synopsis
  • PM10 samples were collected from two suburban locations in northern Spain: a traffic-industrial station in Gijón and an industrial station in Langreo, to analyze levels of toxic elements in the air.
  • Results indicated that concentrations of various metals, including As and Pb, were significantly higher in Langreo compared to Gijón, with Fe and Zn showing the highest levels at both sites.
  • Assessment of health risks revealed that while adults faced acceptable levels of risk, children were more vulnerable, particularly due to exposure to As, Pb, and Zn, which could lead to both carcinogenic and non-carcinogenic health issues.
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Thirty-two chemical species were determined in PM sampled at a suburban site on the north coast of Spain. Enrichment factors were applied to infer their soil/non-soil origin. The geochemical ratios were calculated using two databases: soil composition from locations in the surroundings of the sampling station and the Earth's average upper-crust composition.

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Article Synopsis
  • The study sampled PM10 particles in a suburban area of northern Spain influenced by traffic and industry, focusing on their chemical composition to assess toxicity.
  • Major constituents included total carbon, sulphates, ammonium, chlorides, and nitrates, with a significant correlation between PM10 concentration and nitrate levels.
  • Analysis revealed that many particles were carbon-rich, often resulting from combustion, and posed health risks as a significant portion of them could be inhaled into the respiratory tract, especially the smaller particles.
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To increase the production of methane, when cattle manure (CM) is digested, pretreatments can be applied and/or the manure can be co-digested with other wastes. In this research work, a mixture of CM, food waste (FW) and raw glycerine (Gly) in a proportion in weight of 87% CM, 10% FW and 3% Gly was digested, (a) without pretreatment and (b) with pretreatment by ultrasound, applying a sonication energy of 1040 kJ/kg total solids. Specific methane production was 290 L CH/kg volatile solids (VS) without pretreatment and 520 L CH/kg VS with pretreatment.

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This paper presents a study of the quartz fibrous filters used as a substrate for capturing the particulate matter (PM) present in the air. Although these substrates are widely used in environmental applications, their microstructure has been barely studied. The behavior of these devices during the filtration process was investigated in terms of their microstructure and the quartz fibers.

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Numerous papers related to the estimation of wastewater parameters have used artificial neural networks. Although successful results have been reported, different problems have arisen such as overtraining, local minima and model instability. In this paper, two types of neural networks, feed-forward and neural gas, are trained to obtain a model that estimates the values of nitrates in the effluent stream of a three-step activated sludge system (two oxic and one anoxic).

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Biochemical methane potential (BMP) tests have been carried out on sewage sludge from two wastewater treatment plants to assess the effect of additives (FeCl(3) and two cationic polyelectrolytes) used in sludge dewatering. BMP tests were also carried out on the concentrated solid phase from the enzymic hydrolysis pre-treatment (42 °C, 48 h). FeCl(3) had no significant effect on specific methane production, obtaining 242-246 LCH(4)/kgVSo.

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In the present research study, the weight composition, physical-chemical composition and net calorific values of unsorted municipal solid waste (MSW) generated by a population of around 1,080,000 inhabitants in a region of northern Spain were determined. The unsorted MSW was composed of 38.1% organic fraction and 42.

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