Municipal Wastewater Treatment in a New Type Bio-Carrier Reactor

A newly designed bio-carrier was used in an A/O system to investigate nutrients removal from municipal wastewater. The system was operated for 120 days including two successive phases. Only bio-carrier was used in Phase I without suspended sludge. Suspended sludge was combined with biofilm in Phase II. Results showed that in the whole process, removal efficiency of COD, NH4+-N and TN could be respectively up to 76.0%, 72.6% and 43.3%. A/O system obtained the best treatment effect under the condition of HRT = 16.7 h and internal flux radio = 150%. And in the same conditions, suspended sludge-biofilm in Phase II performed a better removal effect than biofilm in Phase I. In addition, a simplified mathematical model was proposed, which provided an accurate tool for describing the steady-state suspended sludge-biofilm system.