The microbial fuel cell (MFC) is an upsurging technology in the field of bio-energy generation along with wastewater treatment. The microbial fuel cell generates energy with the help of microbes that makes it green future source of energy. In MFC, anaerobic microbes degrade organic matter and produce hydrogen ions (H+) and electrons (e-) at the anode. H+ ion diffuses through the proton exchange membrane (PEM); and e- are transported through an electrode via an external circuit to the cathode. At a cathode, e- and H+ ions combine with oxygen to form water (H2O), this results in power generation [1]. MFC has limited open circuit voltage (OCV) of 1.14 V because of the standard redox potential of NADH/ NAD+ and O2/H2O of -0.32 V and +0.82 V respectively [2]. NAD+ (Nicotinamide adenine dinucleotide) is a coenzyme found in all living cells. It is involved in redox reactions, carrying electrons in reaction during metabolism.
Double chamber MFC has been proven more efficient over single chamber MFC for treatment efficiency as removal of COD, BOD, nitrate, etc. [3, 4]. Advantage of aerobic conditions at the cathode can be taken in both either abiotic or biotic forms. Recently, bio-cathode has attracted attention of many researchers because of the increment in efficiency. In a bio-cathode, microbes act as electron mediator and also provide aerobic treatment. It as well provides a variety of terminal electron acceptors and microbes catalyze electron transfer, diminishing requirement of expensive metals like platinum and electrolyte [6]. Sun et al. [7] obtained 300% increment in power density using the bio - cathode. Hence, sequentially configured bio-anode (anaerobic treatment), and bio-cathode (aerobic treatment) assemblies may enhance per...
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...rrents using stacked microbial fuel cells. Environ. Sci. Technol. 2006; 39: 3388–3394.
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Cyclic voltammetry makes possible the elucidation of the kinetics of electrochemical reactions taking place at the electrode surface [31, 32]. In a typical voltammogram, there can be several peaks. From the sweep-rate dependence of the possible to investigate the role of adsorption, diffusion and coupled homogeneous chemical reaction mechanism. [33]
Fuel cells could create new markets for steel, electronics, electrical and control industries and other equipment suppliers. They could provide tens of thousands of high-quality jobs and reduce trade deficits.
In most cases, hydrogen cannot be stored by itself. Because of this, hydrogen is usually stored in forms of hydrides. One example of a hydride is called a fuel cell. Although other forms of storing hydrogen are found to be difficult, Eisenstien (2000) has found that the cell is not a very complicated device (Eisenstien, 2000, p.22). This is because all that there is to do is to pump hydrogen into one side and then pump oxygen on the other (Eisenstien, March 2000, p.22). This results to the gases combining to form energy and water vapor, which can be used to run electric motors (Eisenstien, March 2000, p.22). Another type of hydride is called a reformer. A reformer is simply a chemical pla...
Talaro , K., & Chess, B. (2012). Foundations in microbiology. (8th ed., pp. 563-564). New York, NY:
Kapley, A., Purohit, H. J., Chhatre, S., Shanker, R., Chakrabarti, T., Khanna, P. (1999). Osmotolerance and hydrocarbon degradation by a genetically engineered microbial consortium. Bioresource technology 67, 241-245.
Stephenson, R., & Blackburn, J. J. (1998). The Industrial Wastewater Systems Handbook. New York: Lewis Publishers.
Not mentioned in the report is a technique called bioremediation, which uses microbes to clean up the hazardous waste. Some small natural organisms, such as bacteria, can eat, digest and gain energy from contaminants, converting them into small amounts of water or innocuous gases. Specific conditions must be present for bioremediation to be successful. Natural amendments can be added if ideal conditions are not present, or contaminated soil can be treated ex situ. Traditionally, it takes anywhere between a few months and several years for bioremediation to fully clean a Superfund site, depending on the size of the site and extent of contamination. Bioremediation is currently being used to clean up contaminated groundwater at the Iceland Coin Laundry Superfund Site in New Jersey (EPA, n.d.). Additionally, experiments are currently underway to determine if fungi can help remediate some of the contamination at the Newtown Creek Superfund Site in New York City (Parry, 2012). As an all-natural alternative, bioremediation is a particularly appealing clean up method. If ideal conditions for microbial growth are not present at the Portland Harbor Superfund site, bioremediation could be a good ex situ treatment
Microbial Fuel cells are extremely versatile, being able to work in a number of different environments with many different conditions. They can use almost all types of waste as long as it’s possible for it to organically decompose; it also does not require a further input of electricity or power. It does however require certain parts and certain bacteria, though many different types are currently being tested out in different research institutes to see which one is the most successful. This is a solar-based alternative energy as the bacteria consume the glucose that arri...
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
There are several types of treatment methods present but biological treatment methods have gained much traction in the recent years due to their low operation costs, comparatively benign effects on the environment and their ease of handling and maintenance. Biological wastewater treatment methods can be subcategorized into dispersed growth systems and attached growth systems. Biofilms fall under the latter category (Sehar & Naz, 2016)
Addition of air and mechanical mixing to enchance the growth of bacteria and ficilitate subsequent waste reduction
Energy, especially from fossil fuels, is a key ingredient for all sectors of a modern economy and plays a fundamental role in improving the quality of life in less developed economies. In 2007, India is ranked fifth in the world in terms of energy demand; accounting for 3.6% of total energy consumed, and is expected to grow at 4.8% in the future. India imports 70% of the oil it uses, and the country has been hit hard by the increasing price of oil, uncertainty and environmental hazards that are concerned with the consumption of fossil fuels. In such context, bio energy constitutes a suitable alternative source of energy for India, as large amounts of raw material are available to be harnessed.
The fuel cell manufactured by Ballard Power Systems is fuel cell that requires hydrogen and oxygen to create electricity. The fuel cell itself consists of two flow field plates, and two thin sheets of catalysts with a Polymer Electrolyte Membrane or Proton Exchange Membrane (PEM) in between (see Figure 1). The hydrogen is fed in through one plate and oxygen collected from the air in another – on either side of the membrane. Of the two electrodes on is the anode and the other is the cathode. The hydrogen reaches the ano...
Leboffe, M. J., & Pierce, B. E. (2010). Microbiology: Laboratory Theory and Application, Third Edition 3rd Edition (3rd Ed.). Morton Publishing
...croorganisms present in wastewater as the anodic solution obtained from different sources made me to understand that microbes present in domestic as well as industrial waste can even be proved beneficial if they are tapped for electricity generation. Such results were based on the preliminary experiments which need further research in the field . I did it on laboratory level and at the end could generate enough electrical energy to light a bulb or to run a calculator for a few hours to a day.