Application of photosynthetic oxygen of microalgae for reducing energy in single algae–nitrification reactor

The paradigm of wastewater treatment system is changing from viewing the municipal wastewater treatment plants (MWTPs) as a center of energy consumption to viewing it as a center of energy production. Recently, many studies have focused on utilizing algae photosynthetic oxygen as a method for energy saving and production in MWTPs. However, such algae are still viewed as a target for treatment and research has been conducted completely on application in Korea. In this research, laboratory-scale algal-nitrification reactors were operated to investigate the practicality of using photosynthesis by algae to increase the energy efficiencies of nitrification in MWTPs. Three operating parameters were mainly examined: hydraulic retention time (HRT), mixed liquor suspended solids (MLSS):algae ratio and light. As a result, stable ammonia nitrogen removal at high efficiency was demonstrated in line with the HRT. When the algae concentration was held constant, the nitrification efficiency increased as the MLSS concentration was reduced. The results of this research could be used as a useful basic data for the algae-nitrification process.