Carbon and nitrogen removal in a biofilm reactors system with raw wastewater stream distribution.

Experiments were carried out on a laboratory scale with four moving bed biofilm reactors (MBBRs) with step-feed. The first and third reactors were anoxic and the second and fourth aerobic. The aim of this experiment was to investigate the system's capacity for, and efficiency of organic carbon and nitrogen removal. Four tests examined the effect of the distribution between stages of raw stream wastewater, the recirculation ratio, and the effect of increasing nitrogen and organic carbon loads on nitrogen and carbon removal. It was concluded that in this system the proper selection of recirculation ratio R, and the parameters of the coefficient of raw wastewater stream distribution theta ensures greater efficiency of nitrogen removal than activated sludge systems.