Environmental Assessment of Co-location Alternatives for a Microalgae Cultivation Plant: A Case Study in the City of Kingston (Canada)

Abstract

In recent years there has been growing interest in the use of microalgae as a feedstock for biofuels, particularly for biodiesel. The production process of biodiesel from microalgae generally consists of five different phases: cultivation, harvesting, drying, lipid extraction and transesterification. While existing technologies are available to undertake each of these phases, the process would benefit from enhanced sustainability achieved by reducing environmental impact and costs. One process innovation currently under consideration is the use of waste products as inputs to the process, including CO2 captured from industrial flue gas, or nutrients from wastewater. These could be employed in algae cultivation. The co-location of an algae cultivation plant with other industrial facilities, such as a cement plant or a wastewater treatment facility, could result in significantly reduced atmospheric emissions and improve wastewater effluent discharges. A comparative life cycle assessment approach is used to examine two different, realistic alternatives for the co-location of an algae cultivation plant with an existing cement plant or wastewater treatment facility near Kingston, Ontario, Canada. The study seeks to identify a preferred siting option from the perspective of minimizing environmental impacts. The first alternative involves the co-location with the Lafarge Cement plant, on the north shore of Lake Ontario, near Bath Ontario. The second alternative consists in the co-location with the Ravensview wastewater treatment facility east of the city of Kingston on the St. Lawrence River. The algae production plant is based on an open pond technology and is assumed to have a production capacity of about 120 tons of dry microalgal biomass per year. © 2016 The Authors

Advances in microalgal lipid extraction for biofuel production: a review

“…A number of studies have been performed to assess the environmental impact of producing microalgal FAMEs for biodiesel. [119][120][121][122] Unfortunately, limited data are available for meaningful comparisons between the various lipid extraction methods as each study uses different microalgal strains, each containing a variable amount of water. Moreover, these microalgal strains are cultivated and harvested under different conditions, which give rise to the production of different quantities and ratios of lipids and fatty acids.…”

“…Some research in this field has been done but progress is still limited, so this should be a focus of the research community moving forward. Life‐cycle assessments are important to highlight the true environmental costs associated with each lipid extraction method. A number of studies have been performed to assess the environmental impact of producing microalgal FAMEs for biodiesel . Unfortunately, limited data are available for meaningful comparisons between the various lipid extraction methods as each study uses different microalgal strains, each containing a variable amount of water.…”

Evaluating microalgae‐to‐energy ‐systems: different approaches to life cycle assessment (LCA) studies

“…It is often suggested that facilities for the production of biofuels should be placed wherever is most convenient, whether close to the feedstock supply, or close to end users . In some cases, facilities could be placed conveniently close to the sources of inputs, for example close to a cement plant (as a source of CO 2 ) or a waste‐water treatment plant (as a source of water and nutrients) . The use of waste water throughout the process seems to be promising way to improve the environmental and economic sustainability of algae cultivation …”

“…cement plants) has been evaluated as a potential source of CO 2 . The co‐location of microalgae production facilities with wastewater treatment plants (or anaerobic digestion facilities) can provide access to nutrients, waste energy and CO 2 , would could maximize the use of waste resources in the process and increase the techno‐economic feasibility of the overall process . Recovery of waste heat and flue gas for the generation of energy products could assist industrial partners in reducing carbon costs under cap‐and‐trade or carbon tax regimes.…”

“…For example, cost estimates could estimate the impact of increased or decreased water volume or arable land use . Similarly, the economic analysis could ‐determine the feasibility of using regional waste streams as resources (CO 2 , waste water, waste heat) and high algal production rates . Determining the economic impact of an investment, as was conducted in one study, was a more arm's‐length approach of measuring benefit as it required an accurate estimate of economic returns (i.e., gross and net profit) as well as accurate measurements of investment.…”