Chiang Mai Journal of Science

 Algae are very important ecologically since they comprised the major portion of primary producers in the aquatic environment. Currently, algal biomass had attracted much interest for the production of food, bioactive compounds and bioenergy. This study utilized the natural water medium to cultivate the algal biomass of the mixed culture with different detention time in the photo-bioreactors. The environmental parameters were monitored continuously during growth period. The study showed that natural water resource had suitable nutrients for micro-algal growth. The best biomass productions were observed in detention times of 10 days and 7 days by the total suspended solids (TSS) average 0.15g/L and 0.14g/L respectively. In the short detention time of 4 days, there was less biomass yield with large amount of water medium consumption. Consequently, we proved the production of algal biomass by the natural water was prospectively feasible in the ecological sense. The study results of the different detention time which represented the various types of natural water bodies could help us to understand the algal growth in the ecosystem better.