Illumination system for growth and net energy ratio enhancement of Arthrospira (Spirulina) platensis outdoor cultivation in deep raceway pond

Abstract

One major problem found in open raceway ponds for algae production is the limited light penetrability, which means that the pond depth should not exceed 25–30 cm. This study aimed to use transparent light-scattering column (LSC) to enhance the brightness in the deeper level of a deep raceway pond. A maximum of 16 LSCs were immersed vertically in the testing pond, which was compared with a control pond without LSC. The results showed that the cultivation period to the stationary phase of the LSC pond was 4 days faster than that of the control pond. The biomass productivity and net energy ratio of the LSC pond were respectively found to increase by about 48.3% and 41.7%, while the water loss from evaporation decreased by about 13.6%. The overview from the results indicated that the environment can be conserved by means of reducing the energy, time and water for cultivation.