Search results for "PAPER"
showing 10 items of 2166 documents
Total (fumarolic + diffuse soil) CO2 output from Furnas volcano
2015
Furnas volcano, in São Miguel island (Azores), being the surface expression of rising hydrothermal steam, is the site of intense carbon dioxide (CO2) release by diffuse degassing and fumaroles. While the diffusive CO2 output has long (since the early 1990s) been characterized by soil CO2 surveys, no information is presently available on the fumarolic CO2 output. Here, we performed (in August 2014) a study in which soil CO2 degassing survey was combined for the first time with the measurement of the fumarolic CO2 flux. The results were achieved by using a GasFinder 2.0 tunable diode laser. Our measurements were performed in two degassing sites at Furnas volcano (Furnas Lake and Furnas Villag…
Cryptogein-Induced Anion Effluxes
2014
Anion effluxes are amongst the earliest reactions of plant cells to elicitors of defence responses. However, their properties and their role in disease resistance remain almost unknown. We previously demonstrated that cryptogein, an elicitor of tobacco defence responses, induces a nitrate (NO(3) (-)) efflux. This efflux is an early prerequisite to the cryptogein-triggered hypersensitive response (HR). Here, we analyzed the electrophysiological properties of the elicitor-mediated NO(3) (-) efflux and clarified the mechanisms through which it contributes to cell death. Application of the discontinuous single electrode voltage-clamp technique in tobacco cells elicited with cryptogein enabled u…
Nouvelles perspectives concernant la structure et la fonction du domaine carboxyl terminal de Hfq
2015
Accumulating evidence indicates that RNA metabolism components assemble into supramolecular cellular structures to mediate functional compartmentalization within the cytoplasmic membrane of the bacterial cell. This cellular compartmentalization could play important roles in the processes of RNA degradation and maturation. These components include Hfq, the RNA chaperone protein, which is involved in the post-transcriptional control of protein synthesis mainly by the virtue of its interactions with several small regulatory ncRNAs (sRNA). The Escherichia coli Hfq is structurally organized into two domains. An N-terminal domain that folds as strongly bent β-sheets within individual protomers to…
Performance of an outdoor membrane photobioreactor for resource recovery from anaerobically treated sewage
2018
[EN] The objective of this work was to evaluate the performance of a pilot scale membrane photobioreactor (MPBR) for treating the effluent of an anaerobic membrane bioreactor (AnMBR) system. In particular, new experimental data on microalgae productivity, nutrient recovery, CO2 biofixation and energy recovery potential was obtained under different operating conditions, which would facilitate moving towards cost-effective microalgae cultivation on wastewater. To this aim, a 2.2-m(3) MPBR equipped with two commercial-scale hollow-fibre ultrafiltration membrane modules was operated treating the nutrient-loaded effluent from an AnMBR for sewage treatment. The influence of several design, enviro…
Comprehensive assessment of the microalgae-nitrifying bacteria competition in microalgae-based wastewater treatment systems: Relevant factors, evalua…
2022
[EN] Due to their capacity to assimilate carbon dioxide and nutrients, microalgae-based cultivation systems have emerged as a green solution for intensive wastewater treatment. However, when large concentrations of ammonium are present the competition between microalgae and ammonium-oxidising bacteria plays a significant role. Microalgae use ammonium to synthesise proteins, photosynthetic pigments and nucleic acids, while ammonium-oxidising bacteria use it as a source of electrons and oxidise it to nitrite.Several authors have studied the isolated factors that influence microalgae-nitrifying bacteria competition, although a comprehensive analysis of this interesting topic is still lacking. …
On-line monitoring of photosynthetic activity based on pH data to assess microalgae cultivation
2020
[EN] Microalgae performance of outdoor cultivation systems is influenced by environmental and operating dynamics. Monitoring and control systems are needed to maximise biomass productivity and nutrient recovery. The goal of this work was to corroborate that pH data could be used to monitor microalgae performance by means of data from an outdoor membrane photobioreactor (MPBR) plant. In this system, microalgae photosynthetic activity was favoured over other physical and biological processes, so that the pH data dynamics was theoretically related to the microalgae carbon uptake rate (CUR). Shortand long-term continuous operations were tested to corroborate the relationship between the first d…
Continuous 3-year outdoor operation of a flat-panel membrane photobioreactor to treat effluent from an anaerobic membrane bioreactor
2020
[EN] A membrane photobioreactor (MPBR) plant was operated continuously for 3 years to evaluate the separate effects of different factors, including: biomass and hydraulic retention times (BRT, HRT), light path (Lp), nitrification rate (NOxR), nutrient loading rates (NLR, PLR) and others. The overall effect of all these parameters which influence MPBR performance had not previously been assessed. The multivariate projection approach chosen for this study provided a good description of the collected data and facilitated their visualisation and interpretation. Forty variables used to control and assess MPBR performance were evaluated during three years of continuous outdoor operation by means …
Resource recovery from sulphate-rich sewage through an innovative anaerobic-based water resource recovery facility (WRRF)
2018
[EN] This research work proposes an innovative water resource recovery facility (WRRF) for the recovery of energy, nutrients and reclaimed water from sewage, which represents a promising approach towards enhanced circular economy scenarios. To this aim, anaerobic technology, microalgae cultivation, and membrane technology were combined in a dedicated platform. The proposed platform produces a high-quality solid- and coliform-free effluent that can be directly discharged to receiving water bodies identified as sensitive areas. Specifically, the content of organic matter, nitrogen and phosphorus in the effluent was 45 mg COD.L-1 , 14.9 mg N.L-1 and 0.5 mg P.L-1 , respectively. Harvested solar…
Outdoor flat-panel membrane photobioreactor to treat the effluent of an anaerobic membrane bioreactor. Influence of operating, design, and environmen…
2018
[EN] As microalgae have the ability to simultaneously remove nutrients from wastewater streams while producing valuable biomass, microalgae-based wastewater treatment is a win-win strategy. Although recent advances have been made in this field in lab conditions, the transition to outdoor conditions on an industrial scale must be further investigated. In this work an outdoor pilot-scale membrane photobioreactor plant was operated for tertiary sewage treatment. The effects of different parameters on microalgae performance were studied including: temperature, light irradiance (solar and artificial irradiance), hydraulic retention time (HRT), biomass retention time (BRT), air sparging system an…
Improving membrane photobioreactor performance by reducing light path: operating conditions and key performance indicators
2020
[EN] Microalgae cultivation has been receiving increasing interest in wastewater remediation due to their ability to assimilate nutrients present in wastewater streams. In this respect, cultivating microalgae in membrane photobioreactors (MPBRs) allows decoupling the solid retention time (SRT) from the hydraulic retention time (HRT), which enables to increase the nutrient load to the photobioreactors (PBRs) while avoiding the wash out of the microalgae biomass. The reduction of the PBR light path from 25 to 10 cm increased the nitrogen and phosphorus recovery rates, microalgae biomass productivity and photosynthetic efficiency by 150, 103, 194 and 67%, respectively.The areal biomass product…