ประสิทธิภาพของสาหร่ายช่อพริกไทย Caulerpa lentillifera และสาหร่ายหนาม Acanthophora spicifera ในการบำบัดสารประกอบไนโตรเจน ในน้ำทิ้งจากบ่อเลี้ยงกุ้งกุลาดำ / อลิสา โชควิวัฒนวนิช = Efficiency of the macroalgae Caulerpa lentillifera and Acanthophora spicifera for the treatment of nitrogen compound from shrimp pond effluent / Alisa Chokwiwattanawanit
Caulerpa lentillifera and Acanthophora spicifera are the macroalgae often used for taking up nitrogen waste in shrimp wastewater treatment pond in Thailand. The present study aims to evaluate photosynthesis efficiency and nitrogen uptake in these algae. It was found that Caulerpa letillifera and Acanthophora spicifera had light saturation, indicated by oxygen evolution, at approximately 15,000-20,000 lux. On the other hand, ammonium and nitrate uptake kinetic of both algae in laboratory condition (30 ppt, 30 ํC and 15000 lux light intensity) were studied using Michaelis-Menten equation. It results showed that Caulerpa lentillifera had maximum ammonium uptake rate (Vmax) and half saturation constant (Km) of 0.0897 mgNH4+ -N/g(fw)/hr and 18.5822 mgNH4+ -N/l, respectively, while Acanthophora spicifera had Vmax = 0.3406 mgNH4+ -N/g(fw)/hr and Km = 50.9554 mgNH4+ -N/l, respectively. For nitrate uptake, Caulerpa lentillifera had maximum nitrate uptake rate (Vmax) of 0.0175 mgNO3- -N/g(fw)/hr with Km = 40.7094 mgNO3- -N/l while Acanthophora spicifera had Vmax = 0.0425 mgNO3- -N/g(fw)/hr and Km = 90.0509 mgNO3- -N/l. The results suggested that Acanthophora spicifera had the higher nitrogen uptake rate than Caulerpa lentillifera. Ammonium was found the primary nitrogen source and high concentration of nitrate was not effect ammonium uptake rate in both algae. In the experiment with the water from shrimp pond algae could rapidly reduce ammonium and the treatment with continuous artificial light (15,000 lux) had higher efficiency than natural light (control). The results also indicated that Acanthophora spicifera had higher treatment efficiency than Caulerpa lentillifera which was related to the kinetics experiments.
