Increasing CO2 concentration impact upon nutrient absorption and removal efficiency of supra intensive shrimp pond wastewater by marine microalgae Tetraselmis chui.

The objective of this study was to investigate the effect of increasing CO2 concentration on the growth and the capability of Tetraselmis chui. in removal of nitrate, ammonium and phosphate from shrimp pond wastewater (SPWW). The factorial experimental design was used with the treatment of SPWW percentage in culture medium, namely: 100% SPWW, 75% SPWW + 25% Sea Water (SW) and 75% SW + 25% SPWW coupled with three CO2 concentration treatments: 390 ppm, 550 ppm and 1000 ppm using CO2 system. Growth of T. chui. for lengh of cultivation period tended to be higher at treatments of 390 ppm CO2 and 100% SPWW, however there was a declining growth over period of cultivation for both treatments. The growth rate of T. chui was higher for all percentage of SPWW treatments in culture medium at 390 ppm CO2 concentration compared to other percentage of SPWW treatments and CO2 concentration treatments. There was a decreasing of growth rate with increasing CO2 concentration at 100% SPWW and 75% SPWW + 25% SW in culture medium. Nitrogen removal efficiency and removal rate by T. chui. were strongly affected by CO2 concentration. However, there was no significant effect of increasing CO2 concentration to removal efficiency and rate of PO4 by T. chui.