scholarly journals Improvement of Hydrogen Production during Anaerobic Fermentation of Food Waste Leachate by Enriched Bacterial Culture Using Biochar as an Additive

2021 ◽  
Vol 9 (12) ◽  
pp. 2438
Author(s):  
Van Hong Thi Pham ◽  
Jaisoo Kim ◽  
Soonwoong Chang ◽  
Woojin Chung

It has become urgent to develop cost-effective and clean technologies for the rapid and efficient treatment of food waste leachate, caused by the rapid accumulation of food waste volume. Moreover, to face the energy crisis, and to avoid dependence on non-renewable energy sources, the investigation of new sustainable and renewable energy sources from organic waste to energy conversion is an attractive option. Green energy biohydrogen production from food waste leachate, using a microbial pathway, is one of the most efficient technologies, due to its eco-friendly nature and high energy yield. Therefore, the present study aimed to evaluate the ability of an enriched bacterial mixture, isolated from forest soil, to enhance hydrogen production from food waste leachate using biochar. A lab-scale analysis was conducted at 35 °C and at different pH values (4, no adjustment, 6, 6.5, 7, and 7.5) over a period of 15 days. The sample with the enriched bacterial mixture supplemented with an optimum of 10 g/L of biochar showed the highest performance, with a maximum hydrogen yield of 1620 mL/day on day three. The total solid and volatile solid removal rates were 78.5% and 75% after 15 days, respectively. Acetic and butyrate acids were the dominant volatile fatty acids produced during the process, as favorable metabolic pathways for accelerating hydrogen production.

Nanoscale ◽  
2021 ◽  
Author(s):  
Woong Choi ◽  
Joon Woo Park ◽  
Woonghyeon Park ◽  
Yousung Jung ◽  
Hyunjoon Song

Electrochemical CO2 reduction reaction (eCO2RR) has been considered one of the potential technologies to store electricity from renewable energy sources into chemical energy. For this aim, designing catalysts with high...


2021 ◽  
Vol 13 (24) ◽  
pp. 13934
Author(s):  
Hanan S. S. Ibrahim ◽  
Ahmed Z. Khan ◽  
Yehya Serag ◽  
Shady Attia

Retrofitting “nearly-zero energy” heritage buildings has always been controversial, due to the usual association of the “nearly-zero energy” target with high energy performance and the utilization of renewable energy sources in highly regarded cultural values of heritage buildings. This paper aims to evaluate the potential of turning heritage building stock into a “nearly-zero energy” in hot, dry climates, which has been addressed in only a few studies. Therefore, a four-phase integrated energy retrofitting methodology was proposed and applied to a sample of heritage residential building stock in Egypt along with microscale analysis on buildings. Three reference buildings were selected, representing the most dominant building typologies. The study combines field measurements and observations with energy simulations. In addition, simulation models were created and calibrated based on monitored data in the reference buildings. The results show that the application of hybrid passive and active non-energy generating scenarios significantly impacts energy use in the reference buildings, e.g., where 66.4% of annual electricity use can be saved. Moreover, the application of solar energy sources approximately covers the energy demand in the reference buildings, e.g., where an annual self-consumption of electricity up to 78% and surplus electricity up to 20.4% can be achieved by using photo-voltaic modules. Furthermore, annual natural gas of up to 66.8% can be saved by using two unglazed solar collectors. Lastly, achieving “nearly-zero energy” was possible for the presented case study area. The originality of this work lies in developing and applying an informed retrofitting (nearly-zero energy) guide to be used as a benchmark energy model for buildings that belong to an important historical era. The findings contribute to fill a gap in existing studies of integrating renewable energy sources to achieve “nearly-zero energy” in heritage buildings in hot climates.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Priyanka Supraja Balaji ◽  
Ellen Torres Thompson ◽  
Lawrence Edmond IV ◽  
Nicole Della Santina

There is a growing need for sustainable forms of renewable energy sources that are efficient, and cost-beneficial. Finding such energy sources is one of the critical challenges of the 21st century. This paper focuses on the prospects of using high energy particles abundant in the universe as a solution to the energy crisis faced around the world. The high energy particle studied in this paper is the neutrino. Neutrinos are subatomic particles that are one-millionth the size of an electron (“How much does a neutrino weigh”, n.d). They are of interest to physicists because they are present virtually everywhere, travel through regular forms of matter, and have exceptionally high energy levels (“What is a Neutrino”, 1999). Neutrinos have ten billion electron volts when traveling freely across space, which is enough energy to break up the nucleus of an atom (“Neutrino Energies”, n.d). Due to their high energy levels and eternal presence, neutrinos are a promising candidate for a renewable energy source. However, due to minimal reactions with other forms of matter, it is difficult to harness their intrinsic energies. A panel that is capable of absorbing neutrinos can potentially produce substantial amounts of heat energy, which can then be converted into electricity.  Energy from neutrinos is a great theoretical alternative and a clean source of energy for our planet and future generations to come. This paper takes another step forward in the mission to produce a primary source of energy that is green and sustainable for our planet.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kehinde Oladoke Olatunji ◽  
Noor A. Ahmed ◽  
Oyetola Ogunkunle

AbstractPopulation increase and industrialization has resulted in high energy demand and consumptions, and presently, fossil fuels are the major source of staple energy, supplying 80% of the entire consumption. This has contributed immensely to the greenhouse gas emission and leading to global warming, and as a result of this, there is a tremendous urgency to investigate and improve fresh and renewable energy sources worldwide. One of such renewable energy sources is biogas that is generated by anaerobic fermentation that uses different wastes such as agricultural residues, animal manure, and other organic wastes. During anaerobic digestion, hydrolysis of substrates is regarded as the most crucial stage in the process of biogas generation. However, this process is not always efficient because of the domineering stableness of substrates to enzymatic or bacteria assaults, but substrates’ pretreatment before biogas production will enhance biogas production. The principal objective of pretreatments is to ease the accessibility of the enzymes to the lignin, cellulose, and hemicellulose which leads to degradation of the substrates. Hence, the use of pretreatment for catalysis of lignocellulose substrates is beneficial for the production of cost-efficient and eco-friendly process. In this review, we discussed different pretreatment technologies of hydrolysis and their restrictions. The review has shown that different pretreatments have varying effects on lignin, cellulose, and hemicellulose degradation and biogas yield of different substrate and the choice of pretreatment technique will devolve on the intending final products of the process.


Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 547
Author(s):  
Marco Martino ◽  
Concetta Ruocco ◽  
Eugenio Meloni ◽  
Pluton Pullumbi ◽  
Vincenzo Palma

Due to its characteristics, hydrogen is considered the energy carrier of the future. Its use as a fuel generates reduced pollution, as if burned it almost exclusively produces water vapor. Hydrogen can be produced from numerous sources, both of fossil and renewable origin, and with as many production processes, which can use renewable or non-renewable energy sources. To achieve carbon neutrality, the sources must necessarily be renewable, and the production processes themselves must use renewable energy sources. In this review article the main characteristics of the most used hydrogen production methods are summarized, mainly focusing on renewable feedstocks, furthermore a series of relevant articles published in the last year, are reviewed. The production methods are grouped according to the type of energy they use; and at the end of each section the strengths and limitations of the processes are highlighted. The conclusions compare the main characteristics of the production processes studied and contextualize their possible use.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5347 ◽  
Author(s):  
Andrea Pietra ◽  
Marco Gianni ◽  
Nicola Zuliani ◽  
Stefano Malabotti ◽  
Rodolfo Taccani

Storing renewable energy in chemicals, like hydrogen, can bring various benefits like high energy density, seasonal storability, possible cost reduction of the final product, and the potential to let renewable power penetrate other markets and to overcome their intermittent availability. In the last year’s production of this gas from renewable energy sources via electrolysis has grown its reputation as one feasible solution to satisfy future zero-emission energy demand. To extend the exploitation of Renewable Energy Source (RES), small-scale conversion plants seem to be an interesting option. In view of a possible widespread adoption of these types of plants, the authors intend to present the experimental characterization of a small-scale hydrogen production and storage plant. The considered experimental plant is based on an alkaline electrolyser and an air-driven hydrogen compression and storage system. The results show that the hydrogen production-specific consumption is, on average, 77 kWh/kgH2. The hydrogen compressor energy requirement is, on average, 15 kWh/kgH2 (data referred to the driving compressed air). The value is higher than data found in literature (4.4–9.3 kWh/kgH2), but the difference can be attributed to the small size of the considered compressor and the choice to limit the compression stages.


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