Search results for "algae"
showing 10 items of 403 documents
HYDROTHERMAL LIQUEFACTION OF MICROALGAE IN THE PRESENCE OF HOMOGENEOUS AND HETEROGENEOUS CATALYSTS
2015
The continuous raise in the prices of fossil fuels and the awareness of the society challenges related to their use has recently driven a strong growth of interest on the investigation of different biochemical or thermochemical processes for the production of liquid biofuels .
Inoculum of Indigenous Microalgae/Activated Sludge for Optimal Treatment of Municipal Wastewaters and Biochemical Composition of Residual Biomass for…
2022
In this work, municipal wastewater was treated with microalgal/activated sludge consortia. We aimed at obtaining a positive interaction between the microalgae and the heterotrophic bacteria and identifying the best combination for bioremediation purposes. A strain of Chlorella sp CW2 employed in this work was isolated from AS and molecularly characterised in this work for the first time. This strain and another previously isolated strain (Chlorella sp Pozzillo) were inoculated alone and in combination with AS in different ratios in wastewaters. Microalgae/activated sludge growth curves were obtained by using a UV–vis spectrophotometer and a fluorimeter to distinguish the contribution of the…
The distinction betweenChondrophycus patentirameusandC. paniculatus(Ceramiales, Rhodophyta)
2000
The red algae Chondrophycus patentirameus (Montagne) Nam (‘patentiramea’) and L. paniculata (C. Agardh) J. Agardh were investigated on the basis of type material and recent collections. Both species show the following features: (i) production of two vegetative pericentral cells from each axial segment; (ii) absence of secondary pit connections between cortical cells; (iii) lack of projecting cortical cells near the apex; (iv) absence of lenticular thickenings in the walls of medullary cells; and (v) perpendicular arrangement of tetrasporangia, each of which is produced from the second pericentral cell in each fertile segment with no additional tetrasporangial pericentral cells. However, C. …
Optimising an outdoor membrane photobioreactor for tertiary sewage treatment
2019
[EN] The operation of an outdoor membrane photobioreactor plant which treated the effluent of an anaerobic membrane bioreactor was optimised. Biomass retention times of 4.5, 6, and 9 days were tested. At a biomass retention time of 4.5 days, maximum nitrogen recovery rate:light irradiance ratios, photosynthetic efficiencies and carbon biofixations of 51.7¿±¿14.3¿mg¿N·mol¿1, 4.4¿±¿1.6% and 0.50¿±¿0.05¿kg CO2·m3influent, respectively, were attained. Minimum membrane fouling rates were achieved when operating at the shortest biomass retention time because of the lower solid concentration and the negligible amount of cyanobacteria and protozoa. Hydraulic retention times of 3.5, 2, and 1.5 days …
Supercritical water gasification of microalgae and their constituents in a continuous reactor
2016
The supercritical water gasification of Nannochloropsis gaditana microalgae has been studied in term of process development at 24 MPa and 663 °C. Gasification has been investigated using a 200 cm3 down flow reactor working continuously. The effect of microalgae slurry concentration, with or without alkali catalysts, was studied. Moreover, the role played by different constituents of microalgae on gasification was investigated. Particularly, gasification of amino acids, carbohydrates and model mixtures among them was studied. Nannochloropsis gaditana was successfully gasified up to 97.4 wt% as gasification efficiency and 86.0 wt% as carbon efficiency. The product gas is mainly composed of hy…
Outdoor microalgae-based urban wastewater treatment: recent advances, applications and future perspectives
2021
[EN] Although microalgae-based wastewater treatment has been traditionally carried out in extensive waste stabilization ponds, recent trends focus on the use of microalgae to apply the circular economy principles in the wastewater treatment sector due to the capacity of algae to absorb carbon dioxide while recovering nutrients from sewage. To this aim, the development of new intensive microalgae-based systems with higher efficiency and level of process control is required. Results obtained for these systems at lab scale are generally promising. However, upscaling to outdoor conditions is often uncertain. Some advances have been made in terms of applying open systems at large scale. However,…
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…
Dataset to assess the shadow effect of an outdoor microalgae culture
2019
[EN] This data in brief (DIB) article is related to a Research article [1]. Microalgae biomass absorb the light photons that are supplied to the culture, reducing the light availability in the inner parts of the photobioreactors. This is known as self-shading or shadow effect. This effect has been widely studied in lab conditions, but information about self-shading in outdoor photobioreactors is scarce. How this shadow effect affects the light availability in an outdoor photobioreactor was evaluated. In addition, advantages and disadvantages of different artificial light sources which can overcome light limitation are described.
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…