Hydraulic characteristics and startup of anaerobic rotating biological contactors

In this study the hydraulic characteristics and the start-up of anaerobic rotating biological contactor (AnRBC) were investigated experimentally and theoretically. Results of tracer study showed that the AnRBC reactor is a well-mixed reactor in the first and second stages. Start-up of the AnRBC reactor was successfully carried out using high strength synthetic wastewaters at hydraulic retention time of 21.6 hours, organic surface loading of 111.4 g-COD/m(2) . d, organic volumetric loading of 13.33 Kg-COD/m(3) . d, disk rotational speed of 12 rpm and 100% disk submergence. In the steady-state operating condition, the removal efficiencies of soluble COD and BOD could be up to 71% and 76% for the inlet COD and BOD concentrations of 12,000 and 7,267 mgL(-1), respectively. The microscopic observations after start-up of the AnRBC reactor showed that the acetogenic bacteria are significant in the first two stages while the methanogenic bacteria predominate in the last two stages.