Biologically induced phosphorus precipitation in aerobic granular sludge process

Aerobic granular sludge is a promising process for nutrient removal in wastewater treatment. In this work, for the first time, biologically induced precipitation of phosphorus as hydroxyl-apatite (Ca5(PO4)3(OH)) in the core of granules is demonstrated by direct spectral and optical analysis: Raman spectroscopy, Energy dispersive X-ray (EDX) coupled with Scanning Electron Microscopy (SEM), and X-ray diffraction analysis are performed simultaneously on aerobic granules cultivated in a batch airlift reactor for 500 days. Results reveal the presence of mineral clusters in the core of granules, concentrating all the calcium and considerable amounts of phosphorus. Hydroxyapatite appears as the major mineral, whereas other minor minerals could be transiently produced but not appreciably accumulated. Biologically induced precipitation was responsible for 45% of the overall P removal in the operating conditions tested, with pH varying from 7.8 to 8.8. Major factors influencing this phenomenon (pH, anaerobic phosphate release, nitrification denitrification) need to be investigated as it is an interesting way to immobilize phosphorus in a stable and valuable product

Editorial: Perceiving and Acting in the real world: from neural activity to behavior

The interaction between perception and action represents one of the pillars of human evolutionary success. Our interactions with the surrounding world involve a variety of behaviors, almost always including movements of the eyes and hands. Such actions rely on neural mechanisms that must process an enormous amount of information in order to generate appropriate motor commands. Yet, compared to the great advancements in the field of perception for cognition, the neural underpinnings of how we control our movements, as well as the interactions between perception and motor control, remain elusive. With this research topic we provide a framework for: 1) the perception of real objects and shapes using visual and haptic information, 2) the reference frames for action and perception, and 3) how perceived target properties are translated into goal-directed actions and object manipulation. The studies in this special issue employ a variety of methodologies that include behavioural kinematics, neuroimaging, transcranial magnetic stimulation and patient cases. Here we provide a brief summary and commentary on the articles included in this research topic

Parameters influencing calcium phosphate precipitation in granular sludge sequencing batch reactor

Parameters influencing calcium phosphate precipitation in Calcium phosphate precipitation inside microbial granules cultivated in a granular sequenced batch reactor (GSBR) has been demonstrated to contribute to phosphorus removal during wastewater treatment. Whereas hydroxyapatite (HAP) is proven to accumulate in the granule, the main calcium phosphate precursors that form prior to HAP are here investigated. A separate batch reactor was used to distinguish reactions involving biological phosphate removal from physicochemical reactions involving phosphateprecipitation in order to establish the kinetics and stoichiometry of calcium phosphate formation. Experiments and simulations with PHREEQC and AQUASIM software support the assumption that amorphous calciumphosphate (ACP) is the intermediary in HAP crystallization. The results provide the kinetic rate constants and thermodynamic constants of ACP. The formation of bioliths inside biological aggregates as well as the main parameters that drive their formations are discussed here. Finally, the influence of pH and calcium and phosphate concentrations in the influent was also assessed, in order to determine the contribution of precipitation in the different operating conditions

Stability and performance of two GSBR operated in alternating anoxic/aerobic or anaerobic/aerobic conditions for nutrient removal

Two granular sludge sequencing batch reactors (GSBR) with alternating anoxic/aerobic (R1) and anaerobic/aerobic (R2) conditions were operated with a 4-carbon-source synthetic influent. The physical properties of the granular sludge were very good (SVI≈20 mL g−1) and high solid concentrations (up to 35 g L−1) were obtained in the bioreactor operated with a pre-anoxic phase with additional nitrate (R1). In contrast, performance and granule settleability were lower in R2 due to the development of filamentous heterotrophic bacteria on the surface of granules. These disturbances were linked to the fact that a fraction of COD remained during the aerobic phase, which was not stored during the anaerobic period. To stabilize a GSBR with a mixture of organic carbon sources, it is thus necessary to maximize the amount of substrate used during the non-aerated, anaerobic or anoxic, phase. Comparable phosphate removal efficiency was observed in both systems; enhanced biological P removal being greater in anaerobic/aerobic conditions, while the contribution of precipitation (Ca–P) was more significant in anoxic/aerobic conditions

Location and chemical composition of microbially induced phosphorus precipitates in anaerobic and aerobic granular sludge

This work focuses on combined scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) applied to granular sludge used for biological treatment of high-strength wastewater effluents. Mineral precipitation is shown to occur in the core of microbial granules under different operating conditions. Three dairy wastewater effluents, from three different upflow anaerobic sludge blanket (UASB) reactors and two aerobic granular sequenced batch reactors (GSBR) were evaluated. The relationship between the solid phase precipitation and the chemical composition of the wastewater was investigated with PHREEQC software (calculation of saturation indexes). Results showed that pH, Ca:P ratios and biological reactions played a major role in controlling the biomineralization phenomena. Thermodynamics calculations can be used to foresee the nature of bio-precipitates, but the location of the mineral concretions will need further investigation as it is certainly due to local microbial activity

How to Choose Weightings to Avoid Collisions in a Restricted Penalty Logic

International audiencePenalty Logic is a natural and commonsense Knowl- edge Representation technique to deal with potentially inconsistent beliefs. Penalty Logic allows some kind of compensation between different pieces of information. But one of the main and less studied flaws of Penalty Logic is the influence of the choice of weights on in- ference: the same pieces of information can provide ex- tremely different results just by changing some weights. This paper concentrates on weightings and on the prob- lem of collisions between interpretations which yield weak conclusions. It focuses more particularly on a family of weightings, the σ -weightings. We show that some of these weightings avoid collisions but that in the meanwhile they disable the mechanism of compensa- tion (and so the interest) of Penalty Logic. We establish then that two of them are suitable for avoiding collisions and maintaining compensation. We obtain their logical characterizations while considering the weightings only and not the associated formulas. Finally, we propose an original weighting, the Paralex Weighting, that improves even more the previous weightings

L'école à l'hôpital: quelle scolarité pour les enfants malades

Ce travail de recherche traite de la scolarité des enfants malades et de l’école à l’hôpital. Je me suis intéressée à la vie de ces enfants, une fois qu’ils n’ont plus la possibilité de rester en classe régulière et à ce qui est mis en place pour leur garantir un moyen de continuer leur scolarité en milieu hospitalier. Je me suis penchée plus spécifiquement sur les moyens mis en oeuvre au sein du Centre Hospitalier Universitaire Vaudois (CHUV), où trois enseignantes sont présentes quotidiennement auprès des enfants malades afin qu’ils puissent poursuivre leur scolarité. Ce travail a pour but de répondre à la question de recherche suivante : Quels sont concrètement les dispositifs mis en place au sein de l’hôpital pour permettre à l’enfant malade, hospitalisé de façon répétée ou/et sur une longue durée de pouvoir poursuivre sa scolarité ? Pour ce faire, je me suis dans un premier temps rendue une semaine au CHUV afin de me plonger dans mon terrain d’études. J’ai pu observer l’école à l’hôpital de l’intérieur et interagir avec les différents acteurs de l’école à l’hôpital. Suite à cela, j’ai mené trois entretiens qualitatifs avec les enseignantes du CHUV, une infirmière et une enseignante donnant ponctuellement des cours de soutien à l’hôpital. Enfin, j’ai confronté et comparé mes observations aux résultats des entretiens menés, ceci dans le but de synthétiser les informations obtenues et de répondre à ma question de recherche

O capitalismo tardio na contemporaneidade Latino-Americana: uma aproximação ao caso Mexicano

Anais do VI Encontro de Iniciação Científica e II Encontro Anual de Iniciação ao Desenvolvimento Tecnológico e Inovação – EICTI 2017 - 04 a 06 de outubro de 2017 - temática Ciências Sociais AplicadasO Capitalismo Tardio (MANDEL, 1982) é uma concepção teórica que visa sintetizar alguns elementos presentes na fase contemporânea do capitalismo. Este estágio se inicia com as derrotas da classe trabalhadora diante dos fascismos e das guerras, desenvolvendo-se a partir da Terceira Revolução Tecnológica. Enquanto uma nova fase de desenvolvimento do capital, este estágio, síntese das etapas anteriores, tem traços distintivos, tais quais “a redução do ciclo vital do capital fixo, a aceleração das inovações tecnológicas (geradoras de rendas que se tornam a principal forma dos superlucros monopolistas sob o capitalismo tardio) e a absorção do capital excedente pelo rearmamento ininterrupto” (MANDEL, 1982, p. 4)Universidade Federal da Integração Latino-Americana (Unila); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação Araucária; Parque Tecnológico Itaipu (PTI) e Companhia de Saneamento do Paraná (SANEPAR

Intracapillary leucocyte accumulation as a novel antihaemorrhagic mechanism in acute pancreatitis in mice

Background: Pancreatic infiltration by leucocytes represents a hallmark in acute pancreatitis. Although leucocytes play an active role in the pathophysiology of this disease, the relation between leucocyte activation, microvascular injury and haemorrhage has not been adequately addressed.Methods: We investigated intrapancreatic leucocyte migration, leucocyte extravasation and pancreatic microperfusion in different models of oedematous and necrotising acute pancreatitis in lys-EGFP-ki mice using fluorescent imaging and time-lapse intravital microscopy.Results: In contrast to the current paradigm of leucocyte recruitment, the initial event of leucocyte activation in acute pancreatitis was represented through a dose- and time-dependent occlusion of pancreatic capillaries by intraluminally migrating leucocytes. Intracapillary leucocyte accumulation (ILA) resulted in dense filling of almost all capillaries close to the area of inflammation and preceded transvenular leucocyte extravasation. ILA was also initiated by isolated exposure of the pancreas to interleukin 8 or fMLP, demonstrating the causal role of chemotactic stimuli in the induction of ILA. The onset of intracapillary leucocyte accumulation was strongly inhibited in LFA-1-/- and ICAM-1-/- mice, but not in Mac-1-/- mice. Moreover, prevention of intracapillary leucocyte accumulation led to the development of massive capillary haemorrhages and transformed mild pancreatitis into lethal haemorrhagic disease.Conclusions: ILA represents a novel protective and potentially lifesaving mechanism of haemostasis in acute pancreatitis. This process depends on expression of LFA-1 and ICAM-1 and precedes the classical steps of the leucocyte recruitment cascade