Comparative Assessment of Pharmaceutical Removal from Wastewater by the Microalgae Chlorella sorokiniana, Chlorella vulgaris and Scenedesmus obliquus

In view of risks associated with the discharge of pharmaceuticals in the aquatic environment, the objective of this work was to assess the removal of paracetamol, salicylic acid and diclofenac from water by a microalgae‐based treatment. For a comparison purpose, the growth and kinetic parameters for the removal of drugs were determined for three different microalgae strains, namely Chlorella sorokiniana, Chlorella vulgaris and Scenedesmus obliquus. It was found that the drugs removal efficiency by these strains was related to their growth. Comparing the three pharmaceuticals, the salicylic acid was the most efficiently removed, especially by S. obliquus (>93% batch culture, >99% semicontinuous culture) and C. sorokiniana (>73% batch culture, >93% semicontinuous culture). Contrarily, paracetamol was the most poorly removed, the maximum efficiencies being those attained by C. sorokiniana (>67% batch culture, >41% semicontinuous culture). On the other hand, diclofenac was efficiently removed only by S. obliquus (>98% batch culture, >79% semicontinuous culture). For the three considered drugs, C. vulgaris was the strain showing the lowest removal capacity. The large differences here revealed between microalgae strains regarding their removal capacity of pharmaceuticals, pointed to the strain selection as a key issue for a successful application in wastewater treatment

Effect of Applying Organic Amendments on the Pyrolytic Behavior of a Poplar Energy Crop

Thermal conversion of biomass derived from energy crops is one alternative for the production of energy. In this work, thermogravimetric analysis of poplar biomass was carried out and both the kinetic parameters (activation energy and frequency factor) and characteristic indexes were determined. Four poplar clones (UNAL, I-214, AF-2 and AF-8) under no fertilization (CONTROL) or under fertilization with either dehydrated composted sewage sludge (BIOSOLIDS) or sludge from dairy wastewater treatment (MUD) were used in this work. Five weight loss stages were identified in the DTG pyrolysis curves: moisture loss, active pyrolysis (two phases), passive pyrolysis and a high-rank pyrolysis phase. Among them, the second pyrolysis active phase was the most representative one. For this stage, BIOSOLIDS-UNAL poplars biomass was the one that achieved the highest weight loss values. The characteristic parameters and indexes (especially P and Pi indexes) also pointed to UNAL poplars under BIOSOLIDS fertilization as the most favourable for pyrolytic thermal conversion.SIAuthors would like to thank funding given by the Junta de Castilla y León (Project LE129A11). Also, Sergio Paniagua and Carla Escapa are grateful to the Spanish Ministry of Education, Culture and Sports for their PhD fellowships (FPU14/05846 and FPU12/03073, respectively)

Chlorella sorokiniana thermogravimetric analysis and combustion characteristic indexes estimation

This work aimed to investigate thermal decomposition of microalgae throughout the different culture stages. For this purpose, Chlorella sorokiniana was cultured in photobioreactors, and microalgae biomass was sampled at different days throughout the development of the culture. The aim was to analyze the energetic value of this biomass by thermogravimetric analysis as well as to calculate combustion characteristic indexes during the different culture stages. In all cases, thermal decomposition of microalgae biomass during combustion denoted two stages. The first one encompassed the carbohydrates and proteins decomposition and the breakdown of hydrocarbon chains of fatty acids, whereas the second step was closely related to the combustion of the formed char. Fuel composition analysis denoted a microalgae HHV value quite similar to that of Poplar (considered as an energy crop) biomass and slightly higher than published values for herbaceous biomass. In relation with the culture stages, a better combustion performance was found (higher thermal indexes as well as higher DTGmax values) for microalgae biomass sampled at days 19 and 21. These results point to the importance of the culture stage for the thermal valorization of microalgae biomass.S

Aprovechamiento de lodos de depuradora. Utilización de la termogravimetría para el seguimiento de los procesos de combustión y estabilización : fabricación de nuevos materiales

[ES] Desde un punto de vista medioambiental resulta evidente la necesidad de llevar a cabo la depuración de las aguas residuales. Ahora bien, el conjunto de tratamientos que esta agua sufren a su paso por una estación depuradora genera unos residuos, los fangos de depuradora, cuyo destino incide igualmente en la calidad del medio, puesto que en ellos se concentran todas aquellas especies que se han retirado de las aguas. Afrontar de forma integral el problema de las aguas residuales, incluyendo todos los aspectos inducidos, como son la disposición de los lodos y su impacto ambiental, suele ser una labor difícil,pero se debe escoger, siempre que sea posible, aquella opción que resulte menos agresiva para el entorno. En este sentido, el presente trabajo supone el estudio de posibles alternativas que permitan su aprovechamiento y valorización. La aplicación agrícola de fangos constituye una practica simple y beneficiosa en muchos casos, aunque no siempre factible. Así, partiendo de la problemática asociada a la utilización de lodos en la agricultura se han planteado, como alternativas, la producción de absorbentes a partir de fangos por un lado y, por otro, su combustión y aprovechamiento energético. El estudio realizado abarca muy diversos campos, lo que implica la utilizacion de una metodologia diversa. En dicha metodologia se ha tratado de incluir el analisis termico como tecnica que, aunque de uso poco frecuente en este ambito, puede aportar informacion relevante. Se ha realizado el seguimiento del tratamiento de digestion de fangos mediante termogravimetria, dada la obligatoriedad de la estabilización de cara a una aplicación agricola. A partir del analisis termico se ha definido un criterio de estabilidad para los lodos estudiados, según el nivel de digestion alcanzad

OPERATING METHOD AT ENGINEERING CLASSES: A TWIST IS NECESSARY

This work aims to transform the conventional class based on simple problem solving by active playful dynamics, in which each student participates actively as a role-play with his/her peers. It has been detected that the way that students have to face the resolution of an engineering problem goes a long way from how it would be solved in the world of work (students are accustomed to raise the resolution of an exercise according to the data that they have). However, the real experience is not so, but it is precisely the acquisition of data, and more specifically, the knowledge of what data to acquire, the real problem in solving this type of exercises. In this sense, a series of play activities were carried out (including the generation of an App) in order that students value the importance of the acquisition of data for the resolution of a problem. The conclusion obtained from this work indicates, on the one hand, the distance between the conventional teaching methodology used and the actual methodology to be applied and, on the other hand, this work presents the new dynamics proposed as a bridge to unify these differences.&nbsp