Research Information System
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH, vol.12, no.3, pp.303-311, 2018 (SCI-Expanded)
Photobioreactor design and determination of operation conditions for pollution removal from wastewater by algae Chlorella vulgaris is a challenge to develop a low cost bioprocess technology alternative to conventional bacterial nutrient removal processes. Fed-batch operation strategy, commonly used in bacterial wastewater treatment, was applied to algal nutrient removal to determine the operating conditions and to evaluate its photobioreactor behavior. The process was operated at different influent NH4-N (12.6-32 mg/L), PO4-P concentrations (3.2-8 mg/L) and then at varying N/P ratio of 4.6/1 and 7.3/1 at NH4-N concentration of 42 +/- 2 mg/L. The other operating conditions were adjusted as light intensity = 1100 lx, LID = 20 h/4 h and hydraulic retention time, HRT = 3 days. The results indicated that nutrient removal in fed-batch operated photobioreactor was mainly affected by the influent NH4-N concentration. The highest NH4-N and PO4-P removal efficiencies were obtained as 84 and 83% at NH4-N = 12.6 mg/L and PO4-P = 3.2 mg/L influent concentrations, respectively. The best N/P ratio for efficient removal of nitrogen (75%) and phosphorus (75%) was determined to be N/P = 4.6. Fed-batch operated photobioreactor provided excess algae growth through which nutrient uptake was enhanced.