Salman's Infobahn

First-generation biofuels (produced primarily from food crops such as grains, sugar beet and oil seeds) are limited in their ability to achieve targets for oil-product substitution, climate change mitigation, and economic growth. Their sustainable production is under scanner, as is the possibility of creating undue competition for land and water used for food and fibre production. The cumulative impacts of these concerns have increased the interest in developing biofuels produced from non-food biomass. Feedstocks from ligno-cellulosic materials include cereal straw, bagasse, forest residues, and purpose-grown energy crops such as vegetative grasses and short rotation forests. These second-generation biofuels could avoid many of the concerns facing first-generation biofuels and potentially offer greater cost reduction potential in the longer term. The largest potential feedstock for ethanol is lignocellulosic biomass, which includes materials such as agricultura...

Depending on the use of the biogas, most trace components must be removed from the biogas. Water vapour can be particularly hazardous because it is highly corrosive when combined with acidic components such as hydrogen sulfide and to a lesser extent, carbon dioxide. The major contaminant in biogas is H 2 S. This component is both poisonous and corrosive, and causes significant damage to piping, equipment and instrumentation. The concentration of various components of biogas has an impact on its ultimate end use. While boilers can withstand concentrations of H 2 S up to 1000 ppm, and relatively low pressures, internal combustion engines operate best when H 2 S is maintained below 100 ppm. Most commonly used methods for hydrogen sulphide removal are internal to the digestion process: ·          air/oxygen dosing to digester biogas and ·          iron chloride dosing to digester slurry. B...

The conversion of organic waste material to energy can proceed along three main pathways – thermochemical, biochemical and physicochemical. Thermochemical conversion, characterized by higher temperature and conversion rates, is best suited for lower moisture feedstock and is generally less selective for products. Thermochemical conversion includes incineration, pyrolysis and gasification. The incineration technology is the controlled combustion of waste with the recovery of heat to produce steam which in turn produces power through steam turbines. Pyrolysis and gasification represent refined thermal treatment methods as alternatives to incineration and are characterized by the transformation of the waste into product gas as energy carrier for later combustion in, for example, a boiler or a gas engine. Bio-chemical conversion processes, which include anaerobic digestion and fermentation, are preferred for wastes having high percentage of organic biodegradable (putrescible) matter and hi...

Ultrasound activated sludge disintegration could positively affect sludge anaerobic digestion. Due to sludge disintegration, organic compounds are transferred from the sludge solids into the aqueous phase resulting in an enhanced biodegradability. Therefore disintegration of sewage sludge is a promising method to enhance anaerobic digestion rates and lead to reduce the volume of sludge digesters. The addition of disintegrated surplus activated sludge and/or foam to the process of sludge anaerobic digestion can lead to markedly better effects of sludge handling at wastewater treatment plants. In the case of disintegrated activated sludge and/or foam addition to the process of anaerobic digestion it is possible to achieve an even twice a higher production of biogas. Here are few examples: STP Bad Bramstedt, Germany (85,000 PE or 4.49 MGD) First fundamental study on pilot scale by Technical University of Hamburg-Harburg, 3 years, 1997 - 1999 • reduction in digestion time from 20 to 4 day...