Zahra Khodabakhshi - MSc. Department of Civil and Environmental Engineering, Babol Noshirvani University of Technology, Babol, Iran
Mohsen Taghavijeloudar - PhD. Department of Civil and Environmental Engineering, Seoul National University, Seoul, Korea

Microalgel-based biological treatment of municipal wastewater has received great attritiondue its simplicity and environmentally friendly features. In this research, FeCl۲ andZnCl۲ were used as trace elements (TEs) to improve microalge growth rate andwastewater treatment ability. The removal of nutrients from real municipal wastewaterwas monitored during ۱۵ days. According to the results, adding ۰.۲ and ۰.۵ mg/L ofFeCl۲ and ZnCl۲ could increase microalge biomass concentration from ۲.۲ mg/L(without adding TEs) to ۳.۲۴ g/L (۴۵%) and ۳.۸۴ g/L (۷۵%), respectively after ۱۲ dayscultivation. The results of nutrients removal revealed that adding TEs couldsignificantly improve microalgal-based biological treatment of municipal wastewater.Based on the treatment results, after ۱۲ days of microalge cultivation in the wastewaterthe final concentrations of COD, PO۴۳, NO۳ and NH۳ were significantly reduces from۱۹۸, ۷.۲۴, ۲.۸۱ and ۳۵.۵ mg/L (without treatment) to ۵۱.۱۲, ۰.۸۱, ۰.۵ and ۵.۴۱ mg/Land۲۲.۱۳, ۰.۱, ۰.۲۵ and ۰.۰۰ mg/L by adding ۰.۵ mg/L of FeCl۲ and ۰.۲ mg/L of ZnCl۲,respectively. The final concentrations of the nutrients in the wastewater meet theminimum stand or reuse-water for agriculture purposes.

Microalage, Municipal Wastewater, Biological Treatment, FeCl۲, ZnCl۲