Characterization and possible uses of ashes from wastewater treatment plants

This work, on the ashes from the wastewater treatment plant of Galindo (Vizcaya, Spain), has been outlined with the purpose of finding their physico-chemical properties and suggesting possible applications. Ashes contain important quantities of iron, calcium, silica, alumina and phosphates. X-Ray diffraction data make it possible to estimate the mineralogical compositions of the original ashes and also, after thermal treatment at 1200 and 1300 degrees C, the main reactions occurring in thermal treatment. Particle size analysis makes it possible to classify ashes as a very fine powdered material. The thermal treatment leads to a densification of the material and provokes losses of weight mainly due to the elimination of water, carbon dioxide and sulphur trioxide. Application tests show that ashes are not suitable for landfill and similar applications, because of their plastic properties. Testing for pozzolanic character, after the ashes had been heated at 1200 degrees C, did not lead to a strong material probably due to low contents in silica and alumina or to requiring a higher heating temperature. Thermal treatment leads to densification of the material with a considerable increase of compressive strength of the probes. The use of additives (clays and powdered glass) to improve ceramic properties of ashes will be the aim of a future work.     

Rainfall and flooding in the Guayas river basin and its effects on the incidence of malaria 1982–1985

Inasmuch as health is at cross purposes with illness, suffering, disability and death, it is clear that all measures that are adopted with foresight to reduce the repercussions of natural disasters have consequences for health     

Distribution-free changepoint detection tests based on the breaking of records

Environmental and Ecological Statistics - The analysis of record-breaking events is of interest in fields such as climatology, hydrology or anthropology. In connection with the record occurrence,...     

The effect of pore geometry in constitutive hysteretic models for unsaturated water flow

Environmental Fluid Mechanics - Water flow in porous media is strongly controlled by the microscale structure of the pore space. Therefore, understanding the dynamics at pore scale is fundamental...     

Assessing the effects of multivariate functional outlier identification and sample robustification on identifying critical PM2.5 air pollution episodes in Medellín,Colombia

Environmental and Ecological Statistics - Identification of critical episodes of environmental pollution, both as a outlier identification problem and as a classification problem, is a usual...     

Modeling the sulfamethoxazole degradation by active chlorine in a flow electrochemical reactor

Environmental Science and Pollution Research - The aim of this study is to propose a continuous physicochemical model accounting for the active chlorine production used to degrade recalcitrant...     

Effects of climate change on species distribution, community structure, and conservation of birds in protected areas in Colombia

Climate change is expected to cause shifts in species distributions worldwide, threatening their viability due to range reductions and altering their representation in protected areas. Biodiversity hotspots might be particularly vulnerable to climate change because they hold large numbers of species with small ranges which could contract even further as species track their optimal habitat. In this study, we assessed the extent to which climate change could cause distribution shifts in threatened and range-restricted birds in Colombia, a megadiverse region that includes the Tropical Andes and Tumbes-Choco-Magdalena hotspots. To evaluate how climate change might influence species in this region, we developed species distribution models using MAXENT. Species are projected to lose on average between 33 and 43 % of their total range under future climate, and up to 18 species may lose their climatically suitable range completely. Species whose suitable climate is projected to disappear occur in mountainous regions, particularly isolated ranges such as the Sierra Nevada de Santa Marta. Depending on the representation target considered, between 46 and 96 % of the species evaluated may be adequately represented in protected areas. In the future, the fraction of species potentially adequately represented is projected to decline to 30–95 %. Additional protected areas may help to retain representativeness of protected areas, but monitoring of species projected to have the largest potential declines in range size will be necessary to assess the need of implementing active management strategies to counteract the effects of climate change.