1 research outputs found
Life Cycle Environmental Impacts of Wastewater-Based Algal Biofuels
Recent research has proposed integrating
wastewater treatment with
algae cultivation as a way of producing algal biofuels at a commercial
scale more sustainably. This study evaluates the environmental performance
of wastewater-based algal biofuels with a well-to-wheel life cycle
assessment (LCA). Production pathways examined include different nutrient
sources (municipal wastewater influent to the activated sludge process,
centrate from the sludge drying process, swine manure, and freshwater
with synthetic fertilizers) combined with emerging biomass conversion
technologies (microwave pyrolysis, combustion, wet lipid extraction,
and hydrothermal liquefaction). Results show that the environmental
performance of wastewater-based algal biofuels is generally better
than freshwater-based algal biofuels, but depends on the characteristics
of the wastewater and the conversion technologies. Of 16 pathways
compared, only the centrate cultivation with wet lipid extraction
pathway and the centrate cultivation with combustion pathway have
lower impacts than petroleum diesel in all environmental categories
examined (fossil fuel use, greenhouse gas emissions, eutrophication
potential, and consumptive water use). The potential for large-scale
implementation of centrate-based algal biofuel, however, is limited
by availability of centrate. Thus, it is unlikely that algal biofuels
can provide a large-scale and environmentally preferable alternative
to petroleum transportation fuels without considerable improvement
in current production technologies. Additionally, the cobenefit of
wastewater-based algal biofuel production as an alternate means of
treating various wastewaters should be further explored