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Light dilution via diffusers:enhancing algal productivity

Badby, Luke (2010) Light dilution via diffusers:enhancing algal productivity. Internship Report, Murdoch University.

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Microalgae are promising feedstock for biofuels. The productivity of these microorganisms greatly exceeds that of oil containing agricultural crops, without competing for arable land. The most common commercial microalgal culture system in use today is the paddlewheel driven raceway pond. The benefits of these ponds include ease of build and operation. The disadvantages include high contamination risks and lower productivity, mainly due to weak light penetration. This report describes the process of testing a device designed to dilute and diffuse light throughout an algal culture, thereby increasing growth and productivity. The limited amount of research that has been done on the concept of spatial light dilution has concentrated on applying the technique to enclosed photobioreactors (PBR). Using devices ranging from as basic as hollow glass cones to sophisticated computer controlled PBR’s, some promising results have emerged. Applying spatial light dilution to a raceway pond has not been reported within the known literature. Light diffusers were designed and constructed by Renewable Energy Investments©, an industry partner. The goal was to find benefits of the diffusers if applied to commercial algae cultivation. A control pond and a test pond were constructed to directly compare the effect of the diffusers on physiological algal characteristics such as growth rate and productivity. Light measurements indicate that under certain conditions the diffusers do enhance irradiance levels within the pond, by as much as 20%. So far no resulting increase in productivity has been observed. It is assumed that other factors are currently limiting any increase in growth. This assumption is currently being tested along with modified versions of the diffusers.

Item Type: Internship Report (Bachelor of Engineering)
Murdoch Affiliation(s): School of Engineering and Energy
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