inoculation and growth of arthrospira maxima in a high-rate algal pond (hrap) to purify biogas from swine waste

Culture de microalgues pour l’obtention de biométhane à partir de biogaz de déchets porcins

In recent years, several technologies have emerged to purify biogas to biomethane, promoting its use as non-fossil fuel, therefore mitigating undesairable methane emissions1. Air pollution is a problem that affects most of the world&#39;s population, particularly in urbanized areas; ultimately, around 92% of the world&#39;s population breathe polluted air2. In Latin America, the air pollution rates are mostly created by the use of fuels, whereby in 2014, 48% of the air pollution was brought on by the electricity and heat production sector3.
In the last decade, more and more studies on the relationship between pollutants in the air and the increase in mortality rates have been proposed, arguing that there is a strong correlation between both datasets, particularly in children populations.
As a way to avoid the continuation of air pollution, several strategies have been proposed; one of these is the use of renewable energy sources, including wind turbines and photovoltaic cells, which diminish the CO2 release into the atmosphere4,5. Another renewable energy source comes from biogas, a byproduct of the anaerobic digestion of organic matter, produced along with a liquid organic digestate6. This gas is composed of a mixture of gasses, and their proportions depend on the source of organic matter used for anaerobic digestion (sewage sludge, cattle manure, or agro-industrial biowaste). Generally, these proportions are CH4 (53%-70%vol), CO2 (30%-47%vol), N2 (0%-3%vol), H2O (5%-10%vol), O2 (0%-1%vol), H2S (0-10,000 ppmv), NH3 (0-100 ppmv), hydrocarbons (0-200 mg/m3) and siloxanes (0-41 mg/m3)7,8,9, where the scientific community is interested in the methane gas since this is the renewable energetic component of the mixture.
However, biogas cannot be simply burned as obtained because the byproducts of the reaction can be harmful and contaminant; this raises the need to treat and purify the mixture to increase the percentage of methane and decrease the rest, essentially converting it into biomethane10. This process is also known as upgrading. Even though, currently, there are commercial technologies for this treatment, these technologies have several economic and environmental drawbacks11,12,13. For example, systems with activated carbon and water washing (ACF-WS), pressure water washing (PWS), gas permeation (GPHR), and pressure swing adsorption (PSA) present some economic or other drawbacks of environmental impact. A viable alternative (Figure 1) is the use of biological systems such as those that combine microalgae and bacteria grown in photobioreactors; some advantages include the simplicity of design and operation, the low operating costs, and its environmentally friendly operations and byproducts10,13,14. When biogas is purified to biomethane, the latter can be used as a substitute for natural gas, and the digestate can be implemented as a source of nutrients to support microalgae growth in the system10.
A method widely used in this upgrading procedure is the growth of microalgae in open raceway photoreactors coupled with an absorption column due to the lower operation costs and the minimal investment capital needed6. The most used type of raceway reactor for this application is the high-rate algal pond (HRAP), which is a shallow raceway pond where the circulation of the algal broth occurs via a low-power paddle wheel14. These reactors need large areas for their installation and are very susceptible to contamination if used in outdoor conditions; in biogas purification processes, it is advised to use alkaline conditions (pH &#62; 9.5) and the use of algal species that thrive in higher pH levels to enhance the removal of CO2 and H2S while avoiding contamination15,16.
This research aimed to determine the biogas treatment efficiencies and final production of biomethane using HRAP photobioreactors coupled with an absorption-desorption column system and a microalgae consortium.

Pleins feux sur l’auteur : Mise à l’échelle de la biotechnologie des microalgues pour une production accrue de biométhane 

Purification du biogaz par l’utilisation d’un système microalgue-bactérien dans des étangs semi-industriels à haute teneur en algues

Our research focuses on developing sustainable and viable microalgal biotechnology for biomethane We show that it was possible to scale the biogas filter up to some industrial scale under other conditions. The process of scaling is aimed at treating larger flows of biogas in smaller facilities with the aim of making it more economically viable. Additionally, the process seeks to promote operating conditions that can lead to greater production of value by products extracted from microalgal biomass.Through a full scale process exposed to outdoor conditions, we have discovered various species of microalgae that enable us to operate the microalgal filter efficiently. We have also identified the optimal operating conditions that lead to a higher volumetric concentration of biomethane. We were able to successfully scale up the microalgal filter to full scale operations, and identify the optimal operating conditions for photo bioreactors and microalgae filter to achieve methane concentrations of up to 85%volume.The use of other species of microalgae under the same operating conditions could improve the performance efficiency of the microalgae filter. In spring summer, the increase in temperature will help the efficiency of the system.

Watch this Scientific Journal Video about Inoculation and Growth of Arthrospira maxima  in a High-Rate Algal Pond HRAP to Purify Biogas from Swine Waste at JoVE.com

Inoculation and Growth of Arthrospira maxima  in a High-Rate Algal Pond (HRAP) to Purify Biogas from Swine Waste  

Inoculation et croissance d’Arthrospira maxima dans un étang d’algues à haut débit (HRAP) pour purifier le biogaz à partir de déchets porcins

Pour commencer, transférez une souche pure d’Arthrospira maxima à partir de plaques de gélose à 15 millilitres de milieu minéral acquiesce. À l’aide du milieu d’acquiescement Jordan, augmentez la culture à des flacons de 500 millilitres. Cultivez-le pendant 12 heures de lumière et d’obscurité à l’aide de lampes LED avec dispositif de montage en surface 2835, fournissant une lumière froide blanche et assurant un mélange continu par bulles d’air.Pour continuer le processus de mise à l’échelle, ajoutez 20 % du volume de culture précédent au nouveau volume jusqu’à ce que 50 litres soient atteints. Adaptez la culture aux conditions de lumière naturelle et aux milieux de culture Jordan dans une serre dans des sacs transparents de 50 litres. Ajoutez le volume total des cinq mètres cubes de photobioréacteurs HRAP à 13 mètres cubes HRAP situés à l’extérieur.Remplissez le reste du volume avec du milieu de culture Jordan. Mélangez les composants à l’aide d’une roue à aubes et cultivez la culture en mode batch pendant 15 jours ou jusqu’à ce qu’elle atteigne 0,7 gramme par litre. Une fois que la croissance atteint 0,7 gramme par litre, transférez le volume au HRAP de 22,2 mètres cubes en fonctionnement.Remplissez le reste avec du support Jordan et réglez la roue à aubes. Laissez la biomasse croître jusqu’à ce qu’elle atteigne 0,7 gramme par litre et un pH de 10. Démarrer la recirculation du liquide du photobioréacteur HRAP vers le réservoir d’absorption à débit variable pour augmenter la productivité de la biomasse.Commencez à faire bouillonner le biogaz à un débit moyen de 3,5 mètres cubes par heure après deux heures pour fournir du carbone inorganique à la culture. Surveillez le pH, en vous assurant qu’il reste au-dessus de neuf.

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Environment

Inoculation and Growth of Arthrospira maxima in a High-Rate Algal Pond (HRAP) to Purify Biogas from Swine Waste

278 vues.  Universidad Nacional Autónoma de México. Pour commencer, transférez une souche pure d’Arthrospira maxima à partir de plaques de gélose à 15 millilitres de milieu minéral acquiesce. À l’aide du milieu d’acquiescement Jordan, augmentez la culture à des flacons de 500 millilitres. Cultivez-le pendant 12 heures de lumière et d’obscurité à l’aide de lampes LED avec dispositif de montage en surface 2835, fournissant une lumière froide blanche et assurant un mélange continu par bulles d’air.Pour continuer le ...

Vidéo: Inoculation and Growth of Arthrospira maxima  in a High-Rate Algal Pond (HRAP) to Purify Biogas from Swine Waste  

Biogas Purification through the use of a Microalgae-Bacterial System in Semi-Industrial High Rate Algal Ponds

In recent years, a number of technologies have emerged to purify biogas into biomethane. This purification entails a reduction in the concentration of polluting gases such as carbon dioxide and hydrogen sulfide to increase the content of methane. In this study, we used a microalgal cultivation technology to treat and purify biogas produced from organic waste from the swine industry to obtain ready-to-use biomethane. For cultivation and purification, two 22.2 m3 open-pond photobioreactors coupled with an absorption-desorption column system were set up in San Juan de los Lagos, Mexico. Several recirculation liquid/biogas ratios (L/G) were tested to obtain the highest removal efficiencies; other parameters, such as pH, dissolved oxygen (DO), temperature, and biomass growth, were measured. The most efficient L/Gs were 1.6 and 2.5, resulting in a treated biogas effluent with a composition of 6.8%vol and 6.6%vol in CO2, respectively, and removal efficiencies for H2S up to 98.9%, as well as maintaining O2 contamination values of less than 2%vol. We found that pH greatly determines CO2 removal, more so than L/G, during cultivation because of its participation in the photosynthetic process of microalgae and its ability to vary pH when solubilized due to its acidic nature. DO, and temperature oscillated as expected from the light-dark natural cycles of photosynthesis and the time of day, respectively. Biomass growth varied with CO2 and nutrient feeding as well as reactor harvesting; however, the trend remained primed for growth.

Air pollution impacts the quality of life of all organisms. Here, we describe the use of microalgae biotechnology for the treatment of biogas (simultaneous removal of carbon dioxide and hydrogen sulfide) and the production of biomethane through semi-industrial open high-rate algal ponds and subsequent analysis of treatment efficiency, pH, dissolved oxygen, and microalgae growth.

In recent years, a number of technologies have emerged to purify biogas into biomethane. This purification entails a reduction in the concentration of ...