Raceway pond

M.A, (2007) Limits to productivity of the alga Pleurochrysis carterae (Hap-tophyta) grown in outdoor raceway ponds. BiotechnoL Bioeng., 96 (1), 27-36,... 

As will be discussed elsewhere in this chapter microalgae are usually grown in dense cultures inside photobioreactors or raceway ponds. Consequently, microalgae will shade each other. Microalgae will experience maximal fight levels at the light-exposed surface of the culture and they will... 

When operating photobioreactors or raceway ponds in batch mode a compromise must be found between achieving a high volumetric... 

Chiaramonti D, Pmssi M, Casini D, et al Review of energy balance in raceway ponds for microalgae cultivation re-thinking a traditional system is possible, Appl Energy 102 101-111, 2013. 

Liffman K, Paterson DA, Liovic P, Bandopadhayay P Comparing the energy efficiency of different high rate algal raceway pond designs using computational fluid dynamics, Chem Eng Res Des 91(2) 221-226, 2013. 

Open systems include raceway ponds, circular ponds and tanks. They resemble mostly closely the nature of microalgae and serve as the oldest and simplest systems for algal produetion. The simplicity lowers the production costs. An open pond usually is shallow (0.25-0.4 m deep) beeause optical absorption and self-shading by the algal cells limits light penetration through the algal broth." ... 

MOHEiMANi N R and BOROWiTZKA M A (2006) The long-term culture of the coccohtho-phore Pleurochrysis carterae (Haptophyta) in outdoor raceway ponds. Journal of Applied Phycology, 18,703-712. 

Raceway pond Less expensive to construct Risk of contamination... 

Algae can be cultivated via an open system (as with natural growth) or a closed system. Raceway ponds are the most commonly used open system for growing algae, while PBRs are a popular closed system for algae cultivation [2,34,37,38]. 

Usually, smaller outdoor raceway ponds produce higher algal yield than a larger pond. Currently, 98% of commercial algae are produced in open systems. The open-pond system can be easily scaled up to several acres for individual ponds and can be... 

PBR technologies for optimal combinaticnis of biomass productivity and craicentra-tion, which have actually been achieved in large-scale PBRs and raceways. The PBRs provide much greater oil yield per hectare than raceway ponds. Both raceway and PBR production methods are technically feasible, however. 

The open pond is an effective reactor for algae growth. Simulation can be used to find the optimal operating conditions, and the traditional raceway pond design could be improved to raise the production rate and lower the cost [7]. 

Raceway ponds are popular algal pond systems and are the preferred production system for many of the commercial operations, including Cyanotech Corporation in Hawaii and Earthrise in California, both of which produce Arthrospira (Spirulim), as well as Seambiotic in Israel (Plate 9.1c). Excessive evaporation is a problem in these regions and a minimum depth of at least 15 cm is required to avoid a reduction in flow which can result in light limitation (Tredici, 1999). 

Raceway ponds can be constructed in a variety of ways. For wall supports, either earthen berms, which are made by moving around and compacting the earth with construction equipment (Lundquist et al., 2010), or concrete walls and floors can be implemented... 

Usually a relatively low cell density is achieved using the raceway pond system (< 1 g dry weight/L). Czech researchers developed an inclined thin-layer cascade system, which is able to sustain much higher cell density (Masojidek et al., 2011). In this system, the turbulent flow of Chlorella cultures on inclined channels is created by gravity a pump is applied to return the cultures fi-om the bottom to the top of the channels. The system is characterized by the highly turbulent flow, thin layer of suspension (less than 1 cm), and high ratio of exposed surface area to total volume, and thus can achieve dramatically higher volumetric yield (up to 40 g/L) than open ponds (Doucha and Livansky, 2009). However, the overall areal productivity obtained from this system is around 20—25 g/m /day (Doucha and Livansky, 2009), similar to that of open ponds (20 g/m /day, Richmond et al., 1990). 

Raceway ponds Fair-good Fair-good None Low Difficult None Very difficult... 

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