Culture studies of phytoplankton isolated from Sumiling Dam and their bioremediation capacity in aquaculture wastewater.

Sumiling Dam in Sarrat, Ilocos Norte, is home to diverse phytoplankton species. This study aims to isolate and identify phytoplankton species, optimize the cultivation of one phytoplankton under varying light, pH, and temperature conditions, and assess its bioremediation capacity in aquaculture wastewater. Three stations were set up at the site, each with three sampling points spaced 3-5 m apart. From each point, 300 ml of water was collected using standard procedures and transported to the lab for phytoplankton identification. Samples were incubated in algae culture broth for 14 days, streak-plated for isolation, and cultured under light. Microscope examination was used to characterize phytoplankton species, and the identification was verified by a professional. Ten phytoplankton species were identified, with Haematococcus sp. selected for wastewater bioremediation due to its optimal growth under specific conditions (81 µmol m-2 s-1, pH 9, 25°C ± 2°C). Experiments showed that Haematococcus sp. significantly reduced nitrogen and phosphorus in wastewater over 7-14 days, with Treatment 3 (1000 mg/l) achieving the highest growth, chlorophyll, and nitrogen reduction, while Treatment 2 (750 mg/l) excelled in phosphorus removal. These results underscore phytoplankton's potential for sustainable, large-scale wastewater bioremediation.