Open-Raceway-Ponds

    The open raceway pond is currently the foremost frequently used and cheapest cultivation system for commercial production of microalgae. Cost investment for these systems range from 0.13 to 0.37 (M€/ha) at 100 ha scale (Chisti, 2012; Norsker et al., 2011). Raceway systems  are used commercially worldwide including the us , Thailand, China, Chile, and Israel to supply microalgae for relatively high-value applications associated with human consumption. At industrial scale, reactors from 1000 to 5000 m2 are used. These are built on compacted soil covered by polymers, although some examples also exist using only compacted soil, for instance , for wastewater treatment (Craggs et al., 2012). In these raceways, the biomass concentration remains on the brink of 0.5 g L− 1 to favour the penetration of sunshine , but this makes the harvesting process harder . Moreover, low biomass cultures are susceptible to contamination by other microorganisms, which increases the danger of culture collapse