Feasibility of Utilizing Moving Bed Biofilm Reactor to Upgrade and Retrofit Municipal Wastewater Treatment Plants

Document Type : Original Research Paper


1 Department of Environmental Engineering, Graduate school of the Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Department of Environmental Health Engineering, Graduate school of Public Health, Tehran Medical Branch, Islamic Azad University, Tehran, Iran

3 Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran


In this study, feasibility of upgrading and retrofitting municipal wastewater treatment plants
was investigated at laboratory scale using Moving Bed Biofilm Reactor (MBBR) process. For this purpose,
an aerobic pilot was operated for nearly one year in different conditions, in which a moving bed carrier with a
specific biofilm surface area of 500 m2/m3 and a filling rate of 60% was utilized. System efficiency in removal of BOD5 and COD was examined at different hydraulic retention times (HRTs) of 1, 1.5, 2, 2.5, 3 and 4 h. The obtained results indicated high ability of the system to tolerate organic loading and to remain stable at a high food to microorganism (F/M) ratio. The system produced effluents with good quality at low HRTs and led to an average BOD5 removal efficiency of nearly 88% during the operational period. The Organic Loading Rate (OLR) applied to the system had a range of 0.73-3.48 kgBOD5/m3.day and 2.43-11.6 gBOD5/m2.day, at which the reactor showed a good performance and stability. In general, it was concluded that (MBBR) can be an excellent alternative for upgrading and optimizing municipal wastewater treatment plants