Search results for "Aigua"
showing 10 items of 90 documents
Founder effects drive the genetic structure of passively dispersed aquatic invertebrates
2018
Populations of passively dispersed organisms in continental aquatic habitats typically show high levels of neutral genetic differentiation, despite their high dispersal capabilities. Several evolutionary factors, including founder events and local adaptation, and life cycle features such as high population growth rates and the presence of propagule banks, have been proposed to be responsible for this paradox. Here, we have modeled the colonization process in these organisms to assess the impact of migration rate, growth rate, population size, local adaptation and life-cycle features on their population genetic structure. Our simulation results show that the strongest effect on population st…
Environment and Space Rule, but Time also Matters for the Organization of Tropical Pond Metacommunities
2020
Metacommunities are dynamic systems, but the influence of time independently of environmental change in their configuration has been rarely considered. Temporary ponds are excellent ecosystem models, as they have well-defined boundaries in time and space; their communities are relatively isolated through a landscape matrix, and the progress of time leads to major changes through ecological succession and in habitat suitability related to hydroperiod dynamics. Therefore, strong temporal effects are expected to influence their metacommunity structure. We surveyed 30 temporary ponds along the dry tropical region of western Costa Rica and Nicaragua at three different moments of their hydroperio…
Granulation and microbial community dynamics in the chitosan-supplemented anaerobic treatment of wastewater polluted with organic solvents.
2018
Abstract The effect of chitosan on the development of granular sludge in upflow anaerobic sludge blanket reactors (UASB) when treating wastewater polluted with the organic solvents ethanol, ethyl acetate, and 1-ethoxy-2-propanol was evaluated. Three UASB reactors were operated for 219 days at ambient temperature with an organic loading rate (OLR) of between 0.3 kg COD m −3 d −1 and 20 kg COD m −3 d −1 . One reactor was operated without the addition of chitosan, while the other two were operated with the addition of chitosan doses of 2.4 mg gVSS −1 two times. The three reactors were all able to treat the OLR tested with COD removal efficiencies greater than 90%. However, the time required to…
Decision support systems (DSS) for wastewater treatment plants - A review of the state of the art.
2019
The use of decision support systems (DSS) allows integrating all the issues related with sustainable development in view of providing a useful support to solve multi-scenario problems. In this work an extensive review on the DSSs applied to wastewater treatment plants (WWTPs) is presented. The main aim of the work is to provide an updated compendium on DSSs in view of supporting researchers and engineers on the selection of the most suitable method to address their management/operation/design problems. Results showed that DSSs were mostly used as a comprehensive tool that is capable of integrating several data and a multi-criteria perspective in order to provide more reliable results. Only …
Are there so many congeneric species of chironomid larvae in a small stream?
2018
The co-occurrence of larvae of congeneric chironomid species is common in natural stream assemblages, and raises the problem of finding mechanisms to explain the co-existence of species with similar ecological requirements. In this contribution, we explored the co-occurrence of chironomid larvae belonging to congeneric species within four genera of chironomids: Cricotopus, Eukiefferiella, Orthocladius and Rheocricotopus (with 2, 7, 2 and 4 species, respectively) in the headwaters of a small Mediterranean calcareous stream. Due to the intrinsic, natural spatial and temporal variability in these habitats, we studied three different sites at two different seasons within the annual hydrological…
Analysis of uncontrolled phosphorus precipitation in anaerobic digesters under thermophilic and mesophilic conditions.
2019
This study compares the operation of mesophilic and thermophilic anaerobic digestion of sewage sludge and their effects in uncontrolled phosphorus precipitation. The research has been carried out using a pilot plant consisting of two digesters of 1.6 m3 working volume, treating the mixed sludge of Alzira WWTP (Valencia, Spain). The digesters were operated in parallel, at different conditions: mesophilic (38 ± 2.0°C) and thermophilic (55 ± 2.5°C) temperatures and organic loading rates (OLR) ranging from 1.1 to 1.7 kg volatile solids (VS) m−3 d−1 and different hydraulic retention times (HRT) 20, 15 and 12 days. Uncontrolled precipitation was evaluated through P, Mg and Ca mass balances in bot…
Inter- and intraspecific variability in invertebrate acute toxicity response to Arsenic and Fluoride exposure
2018
The adverse effects of arsenic and fluoride exposure on six groups of freshwater invertebrates were investigated. Acute toxicity tests (48-h) with arsenic trioxide (As2NO3) resulted in the following pattern of sensitivity: Daphnia magna 24-h-old = Brachionus patulus 72-h-old = Daphnia. cf. prolata, 21-d-old = D. magna 5-d-old > Heterocypris incongruens juvenile instars > Culex sp. Heterocypris juv. incongruens instars were the second group more tolerant to arsenic and the second group that bioconcentrates arsenic the least. In contrast, invertebrates exposed to sodium fluoride (NaF), showed a different pattern of sensitivity: H. incongruens instars > B. patulus = D. magna 24-h-old > D. cf. …
A comprehensive assessment of energy efficiency of wastewater treatment plants: An efficiency analysis tree approach
2023
Producción Científica
Eliminación de metales pesados en aguas mediante bioadsorción. Evaluación de materiales y modelación del proceso.
2010
Una de las principales fuentes de contaminación de las aguas es el vertido de efluentes insuficientemente depurados, razón por la que el control de vertidos ha centrado gran parte de las actuaciones legislativas de las administraciones competentes en esta materia. Las técnicas convencionales de depuración de metales pesados presentan dificultades para lograr el cumplimiento de los límites de vertido siendo necesaria la búsqueda de técnicas alternativas para reducir estas emisiones. En este sentido, la investigación en bioadsorción ha mostrado en los últimos años el potencial de esta tecnología para el tratamiento de aguas contaminadas por metales pesados. El objetivo de la tesis doctoral es…
Water Supply in Rwanda Use of Photovoltaic Systems for Irrigation
2015
The current energy situation in the world where most of the energy needed is generated from non-renewable sources such as fossil fuels is no longer sustainable. During few years, nonrenewable sources have become an interesting solution to provide energy to areas with small needs of electricity, rather than using non-renewable sources. Therefore, this project has pursued to implement photovoltaics panels to supply energy in a rural region in central Africa, contributing to the development of the area and proving that this technology is viable to pump water for irrigation instead of the conventional electric grid. A rural area between Kidogo Lake and Rilima town, in Bugesera district of Rwand…