Architectural adaptations of microbial fuel cells.

Conventional wastewater treatment consumes a large amount of money worldwide for removal of pollutants prior to its discharge into water body or facilitating reuse. Decreasing energy expenditure during wastewater treatment and rather recovering some value-added products while treating wastewater is an important goal for researchers. Microbial fuel cells (MFCs) are representative bioelectrochemical systems, which offer energy-efficient wastewater treatment. MFCs convert chemical energy of organic matter into electrical energy by using biocatalytic activities. Although MFCs are not truly commercialized, they have potential to make energy-gaining wastewater treatment technologies and represent their capabilities successfully. Over the last decade, MFCs have developed remarkably in almost every dimension including wastewater treatment capabilities, power output, and cost optimization; however, its architectural design is an important consideration for scaling up. Here, we review various architectural advancements and technology up-gradation MFCs have experienced during its journey, to take this technology step forward for commercialization.

Opportunities for public water utilities in the market of energy from water.

An inventory is made of the possibilities to recover sustainable energy from the water cycle by identifying different water flows in a municipal environment as a sustainable energy source. It is discussed what role public water utilities should play in the market of energy from water. This is done for Waternet, the public water utility of Amsterdam, by describing experiences on two practical applications for aquifer thermal energy storage and energy recovery from drinking water. The main conclusion is that public water utilities can substantially contribute to the production of sustainable energy, especially by making use of heat and cold from the water cycle. Public water utilities have the opportunity to both regulate and enter the market for energy from water.

Three-dimensional carbon nanotube-textile anode for high-performance microbial fuel cells.

Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater.

Algal biodiesel economy and competition among bio-fuels.

This investigation examines the possible results of policy support in developed and developing economies for developing algal biodiesel through to 2040. This investigation adopts the Taiwan General Equilibrium Model-Energy for Bio-fuels (TAIGEM-EB) to predict competition among the development of algal biodiesel, bioethanol and conventional crop-based biodiesel. Analytical results show that algal biodiesel will not be the major energy source in 2040 without strong support in developed economies. In contrast, bioethanol enjoys a development advantage relative to both forms of biodiesel. Finally, algal biodiesel will almost completely replace conventional biodiesel. CO(2) reduction benefits the development of the bio-fuels industry.

[Biomass energy utilization in microbial fuel cells: potentials and challenges].

Microbial fuel cells (MFCs) that can harvest biomass energy from organic wastes through microbial catalysis have garnered more and more attention within the past decade due to its potential benefits to ecological environment. In this article, the updated progress in MFCs is reviewed, with a focus on frontier technologies such as chamber configurations, feedstock varieties and the integration of MFCs with microbial electrolysis cells for hydrogen production. And on the other hand, the challenges like development of cost-effective electrode materials, improvement of biomass energy recovery and power output, design and optimization of commercial MFC devices are presented.

Assessment of technologies to meet a low carbon fuel standard.

California's low carbon fuel standard (LCFS) was designed to incentivize a diverse array of available strategies for reducing transportation greenhouse gas (GHG) emissions. It provides strong incentives for fuels with lower GHG emissions, while explicitly requiring a 10% reduction in California's transportation fuel GHG intensity by 2020. This paper investigates the potential for cost-effective GHG reductions from electrification and expanded use of biofuels. The analysis indicates that fuel providers could meetthe standard using a portfolio approach that employs both biofuels and electricity, which would reduce the risks and uncertainties associated with the progress of cellulosic and battery technologies, feedstock prices, land availability, and the sustainability of the various compliance approaches. Our analysis is based on the details of California's development of an LCFS; however, this research approach could be generalizable to a national U.S. standard and to similar programs in Europe and Canada.

The Roundtable on Sustainable Biofuels: plant scientist input needed.

The Energy Center at the Ecole Polytechnique Fédérale de Lausanne (Swiss federal institute of technology) is coordinating a multi-stakeholder effort, the Roundtable on Sustainable Biofuels (http://energycenter.epfl.ch/biofuels), to develop global standards for sustainable biofuels production and processing. Given that many of the aspects related to biofuel production request a high scientific level of understanding, it is crucial that scientists take part in the discussion.

Driving biofuels from field to fuel tank.

Rising oil prices, fears of global warming, and instability in oil-producing countries have ignited the rush to produce biofuels from plants. The science is progressing rapidly, driven by favorable policies and generous financing, but many hurdles remain before cars and trucks run on "gasohol" or "grassoline."

Engineering microbial fuels cells: recent patents and new directions.

Fundamental research into how microbes generate electricity within microbial fuel cells (MFCs) has far outweighed the practical application and large scale development of microbial energy harvesting devices. MFCs are considered alternatives to standard commercial polymer electrolyte membrane (PEM) fuel cell technology because the fuel supply does not need to be purified, ambient operating temperatures are maintained with biologically compatible materials, and the biological catalyst is self-regenerating. The generation of electricity during wastewater treatment using MFCs may profoundly affect the approach to anaerobic treatment technologies used in wastewater treatment as a result of developing this energy harvesting technology. However, the materials and engineering designs for MFCs were identical to commercial fuel cells until 2003. Compared to commercial fuel cells, MFCs will remain underdeveloped as long as low power densities are generated from the best systems. The variety of designs for MFCs has expanded rapidly in the last five years in the literature, but the patent protection has lagged behind. This review will cover recent and important patents relating to MFC designs and progress.