Sustainable Development of Algal Biofuels in the United States (2012) / Chapter Skim
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5 Environmental Effects
5 Environmental Effects
Pages 139-190
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From page 139... ...
Potential environmental effects discussed in this chapter include those resulting from land-use changes, water quality, net greenhousegas (GHG) emissions, air quality, biodiversity, waste generation, and effects from genetically engineered algae (with an emphasis on new or enhanced traits)
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From page 140... ...
Some of the environmental risks might require exploratory assessment and subsequent monitoring to ensure that they do not become sustainability concerns if algal biofuel production is scaled up. 5.1 WATER QUALITY Producing algal biofuels could improve or harm water quality depending on the resource input and management used in algae cultivation, weather events, integrity of infrastructure, and processing of spent water.
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From page 141... ...
However, producers are likely to take preventive measures when extreme weather events are forecasted, and they would put effort into preventing accidental releases of cultivation water because such events could adversely affect their profit margin. 5.1.2 Eutrophication 5.1.2.1 Potential Environmental Effects Large-scale algae cultivation requires the provision of large quantities of nutrients, especially nitrogen and phosphorus, to ensure high yield (see section Nutrients in Chapter 4)
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From page 142... ...
It is unknown whether rare releases of culture water or the physical appearance of open ponds for algae cultivation could have negative effects on the social acceptability of algal biofuels. 5.1.2.2 Opportunities for Mitigation Quantifying water losses from raceways, ponds, or photobioreactors would indicate whether repairs of small leaks are necessary.
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From page 143... ...
. 5.1.4 Groundwater Pollution 5.1.4.1 Potential Environmental Effects Open ponds may not be suitable for many soil types without using lining, and a thorough review of potential effects on surface water and groundwater quality would have to be conducted if clay-lined ponds are to be used.
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From page 144... ...
during extreme weather events would be helpful in preventing water pollution. 5.1.5 Wastewater Treatment Wastewaters derived from municipal, agricultural, and industrial activities potentially could be used for cultivating algal feedstocks either in open ponds or in photobioreactors for algal biofuels and could provide an environmental benefit.
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. Whether pollutant uptake by algae is desirable depends on whether coproducts are to be produced with algal biofuels or whether the lipid-extracted algae are to be used for nutrient recycling.
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. Concentrations of nutrients are included because they relate to benefits or potentially adverse effects on water quality (for example, eutrophication)
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From page 147... ...
need to be characterized, particularly if wastewater or produced water is used as culture medium. Information on the nutrient removal efficiencies of commercial-scale facilities would be needed if algal biofuel production is to be combined with wastewater treatment.
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From page 148... ...
Competing land demands could change over time and may influence the landscape of algal biofuels. For example, some of the same lands that are attractive for algal biofuel development are also attractive for large-scale solar power development (BLM and DOE, 2010)
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From page 149... ...
The indirect land-use changes not only affect ecosystem services, but result in changes in GHG emissions that have to be considered in life-cycle GHG assessments for algal biofuels. If the indirect effects of algal biofuel production are to be quantified, then the potential biodiversity, water quality, and water balance impacts would include those associated with indirect land conversions.
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From page 150... ...
. TABLE 5-3 Illustrative Land Condition Factors for Land-Cover Changes Relevant to Algal Biofuel Production Land Use or Land Cover Type Land Conditionc Builta (refineries, offices)
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From page 151... ...
studies of GHG emissions are reviewed critically. 5.3.1 Life-Cycle GHG Emissions of Algal Biofuels Primary GHG emissions from algal biofuels are expected to be connected to the use of energy in the processing chain (see section Energy in Chapter 4)
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From page 152... ...
It is, however, premature to conclude that algal biofuels based on recycling CO2 and producing biogas has net negative GHG emissions. The variability in Table 5-5 is based on differences in energy data and assumptions in the six existing studies.
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From page 153... ...
The potential for N2O and methane emissions could be reduced through thorough mixing and proper management of algae cultivation (Fagerstone et al., 2011)
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From page 154... ...
5.4.3 Information and Data Gaps While parallels can be drawn from the introduction of large reservoirs in arid regions, the variability in size, geography, and production methods that will emerge as the algae industry grows will necessitate additional research to fully understand and address the impacts associated with local climate alteration. 5.5 AIR QUALITY 5.5.1 Potential Environmental Effects The air quality impacts of algal biofuel production will depend on system design.
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From page 155... ...
However, emissions from fossil fuels used along the production pathway of algal biofuel would need to be considered in any LCA of the airquality impacts of different algal biofuel designs. Further, how algal biofuels will be scaled up and how air quality might change with increasing scale is uncertain.
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From page 156... ...
5.5.1.5 Anaerobic Digestion Anaerobic digestion for processing wastewater from algal biofuel production facilities is described in Chapter 2. NH3 has been observed to be present in biogas from anaerobic digestion at concentrations up to 450 ppm (Schomaker, 2000)
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From page 157... ...
. 5.5.1.7 Life-Cycle Assessment Emissions of air pollutants need to be assessed over the life cycle of algal biofuels and compared to petroleum-based fuels and other alternatives.
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From page 158... ...
If an algal biofuel facility is located near human populations, measures likely will be taken to contain or limit the release of any products that negatively affect local air quality or are perceived to be a risk to public health. The health costs of some types of air emissions were discussed in Hill et al.
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From page 159... ...
Siting facilities at a distance from human population centers and ecological species of concern would mitigate potential adverse effects of air pollution on humans. 5.5.5 Sustainability Indicators Appropriate sustainability metrics for air quality would depend on the processes used in algal biofuel production.
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From page 160... ...
5.6.2 Releases of Algae to Natural Environments Releases of improved nongenetically engineered or genetically engineered strains of algae from biofuel production cultures to natural environments can be expected to be common, especially from open ponds. Releases may occur during the feedstock production stage or possibly during the harvesting or drying stages.
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From page 161... ...
Although some researchers and producers are considering the use of regionally native species that are adapted to the local climate (Odlare et al., 2011) , other algal production facilities may use nonnative species or species that have been selected and bred or genetically modified for desirable characteristics for algal biofuel production.
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From page 162... ...
Invasiveness varies in different natural environments, and site-specific assessments might be necessary to reduce risks of invasion. Moreover, species that are intolerant of conditions in natural waters (for example, salinity)
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Additional sustainability indicators for aquatic biodiversity might include the types of metrics found in recovery plans for species protected under the Endangered Species Act (Table 5-9)
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influence the magnitude of potential effects on ecological populations and communities. Displacement of native vegetation and individual vertebrates usually is limited to the area of the facility, but some species are sensitive to human infrastructure and tend to be displaced to distances beyond the boundaries of the facility, for example, female sage grouse avoiding nesting within 950 meters of infrastructure associated with natural gas fields (Holloran et al., 2010)
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From page 165... ...
In planning the size of individual ponds, their density on the landscape, and associated production facilities, managers would have to consider potential environmental impacts on biodiversity. 5.7.2 Wildlife Drinking 5.7.2.1 Potential Environmental Effects Open algal ponds may be sources of water to wildlife that may prove beneficial in arid conditions or harmful if toxic to certain species.
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. To consider potential exposures of wildlife to toxicants in culture water from algal biofuel facilities and their potential effects, analogies may be made to agricultural evaporation ponds and oil-field wastewater evaporation ponds.
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From page 167... ...
Similarly, mitigation strategies used in agricultural evaporation ponds, such as steepening pond slopes or maintaining deep water levels that reduce suitability of bird feeding habitat, are not practical for algae cultivation that requires shallow ponds (Evaporation Ponds Technical Committee, 1999)
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Some algal biofuel companies, such as Algenol and Synthetic Genomics, are conducting research on genetically engineered organisms for algal biofuel production (Gressel, 2008)
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. Predictors of potential adverse effects of genetically engineered algae include probability of release, abundance of organisms released (predictor of establishment)
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are less likely to have new traits and to cause adverse effects. 5.8.2 Social Acceptability of Genetically Engineered Algae If algal biofuel companies are moving toward the use of genetically engineered algae, popular and political resistance could be anticipated.
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suggested that options regarding the use of genetically engineered organisms for hazardous waste remediation likely would be presented in the context of multiple technology options. It is less likely that stakeholders evaluating the use of genetically engineered algae in their regions would be explicitly weighing the relative benefits and risks of different liquid fuels produced elsewhere.
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From page 172... ...
Moreover, markers could be added to algae to allow easy measurement in specific media. 5.8.5 Information and Data Gaps The ecological risks of a release of genetically engineered microorganisms have to be carefully assessed before they are used in commercial-scale algal biofuel production.
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, who chaired the "Committee on Technical Standards" for the Algal Biomass Organization, "there are as many proposed processes for producing algal biofuels as there are companies." Thus, whether generation of waste products would be a concern cannot be known until operations at commercial scale are in place and compositions can be ascertained. Maximizing recycling would reduce the need for waste product disposal.
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From page 174... ...
The current state of knowledge about phytoplankton community composition is not sufficient to predict whether toxin-producing strains could invade and bloom in algal biofuel production systems, even if these systems are seeded either initially or continuously with non-toxigenic algal strains. Compounds presently not known to be harmful because of their presence in low concentrations in small-scale, low-intensity algal biomass production may have harmful impacts when concentrated 100,000 times during the harvesting and drying phases.
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From page 175... ...
, or manures are used as water or nutrient supplies. Although the algal cultivation systems using wastewater are similar to the thousands of algal wastewater ponds in the United States, different occupational exposures might arise because the algal biomass being handled in algal biofuel production is larger in quantity (that is, higher sludge mass in algae cultivation for fuels than in algal wastewater pond)
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From page 176... ...
. 5.10.4 Sustainability Indicators for Algal Toxins and Pathogens Indicators of sustainable development of algal biofuels include metrics of algal toxins and pathogens in water, which consist of concentrations of toxins in water, measures of toxic effects (for example, in animal models)
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From page 177... ...
. 5.11 MOSQUITO-BORNE DISEASES 5.11.1 Potential Environmental, Health, and Social Acceptability Effects Health effects from and social acceptability of algal biofuels could be affected if open ponds are poorly managed and provide habitats for mosquito larvae.
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From page 178... ...
5.12 CONCLUSIONS Reducing GHG emissions from the transportation sector has been one of the primary motivations for using alternative liquid transportation fuels. Therefore, the life-cycle GHG emissions are key factors in considering the sustainable development of algal biofuels.
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· Effects on terrestrial biodiversity from changing landscape pattern as a result of infrastructure development for algal biofuels. · Potential adverse effects and unintended consequences of introduction of geneti cally engineered algae for biofuel production.
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From page 180... ...
2008. Opportunities and challenges in algae biofuel production.
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From page 181... ...
Received by the NRC Committee on Sustainable Development of Algal Biofuels on July 25.
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From page 182... ...
2011. Quantitative measurement of direct nitrous oxide emissions from microalgae cultivation.
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2009. Air quality issues associ ated with biofuel production and use.
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2010. Comparative energy life-cycle analyses of microalgal biomass production in open ponds and photobioreactors.
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Bioresource Technology 73(3)
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From page 186... ...
2011. The potential of sustainable algal biofuel production using wastewater resources.
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Presentation to the NRC Committee on Sustainable Development of Algal Biofuels on June 13. Scheffer, M., S
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2012. Genetically engineered algae for biofuels: A key role for ecologists.
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2010. An outlook on microalgal biofuels.
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2012. Acetic acid-induced programmed cell death and release of volatile organic compounds in Chlamydomonas reinhardtii.
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