We model a municipal solid waste (MSW)-to-ethanol facility that employs dilute acid hydrolysis and gravity pressure vessel technology and estimate life cycle energy use and air emissions. We compare our results, assuming the ethanol is utilized as E85 (blended with 15% gasoline) in a light-duty vehicle, with extant life cycle assessments of gasoline, corn-ethanol, and energy crop-cellulosic-ethanol fueled vehicles. We also compare MSW-ethanol production, as a waste management alternative, with landfilling with gas recovery options. We find that the life cycle total energy use per vehicle mile traveled for MSW-ethanol is less than that of corn-ethanol and cellulosic-ethanol; and energy use from petroleum sources for MSW-ethanol is lower than for the other fuels. MSW-ethanol use in vehicles reduces net greenhouse gas (GHG) emissions by 65% compared to gasoline, and by 58% when compared to corn-ethanol. Relative GHG performance with respect to cellulosic ethanol depends on whether MSW classification is included or not. Converting MSW to ethanol will result in net fossil energy savings of 397-1830 MJ/MT MSW compared to net fossil energy consumption of 177-577 MJ/MT MSW for landfilling. However, landfilling with LFG recovery either for flaring or for electricity production results in greater reductions in GHG emissions compared to MSW-to-ethanol conversion.
Petroleum sludge is a complex mixture of hydrocarbons, water, metals, and suspended fine solids. The objective of this research was to develop a technique that will lead to the separation of phases ready for further reuse. A study was carried out to investigate a combination of various systems of electrokinetic cells, to which oily sludge, conditioning liquids, and different electrical potentials were applied. The developed electrokinetic phase separation is a new cost-effective technology, which in turn will permit the revitalization of petroleum sludge. This method can significantly reduce the amount of wasted sludge and can recover new fuels free of metals and water. Life cycle analysis of the recovered fuel shows that a new petroleum waste management protocol might reduce emissions of major greenhouse gases such as CO2, CH4, and N2O by 40 026 000, 1057, and 566 kg, respectively, per refinery per year.Key words: oily sludge, electrokinetics, fuel recovery, sustainable management, life cycle analysis.
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