Food-based sizing criteria of bead filters with floating media in serial treatment with moving bed bioreactors

The bead filter and moving bed biological reactor (MBBR) are two common technologies used in tandem to remove solids and ammonia from recirculating aquaculture systems. While the sizing of these two technologies is well understood when designed separately, the same sizing guidelines lead to inefficiencies when the two are used together. This is primarily due to the sizing by part design philosophy not considering processes that occur in multiple system components. In response, the authors have reviewed and amended sizing recommendation to avoid unnecessary oversizing. This analysis presents three cases to examine how sizing by parts can lead to system inefficiencies and to lay out a better design approach. Case 1 utilizes the bead filter as a solids capture device, ignoring the impact of the system’s recirculating flow rate and bead filter’s nitrification capacity. Case 2 uses the bead filter’s volume to determine the system’s recirculating flow rate without considering the bead filter’s nitrification capacity. In Case 3 the bead filter’s nitrification capacity is utilized in sizing the moving bed reactor placed in series after the bead filter. In summary, the high-rate floating bead filters (Ω=2888 m3 day −1 m−3 media) should be utilized to remove solids prior to a moving bed reactor and the nitrification capacity of the floating bead filter should be consideration in the MBBR sizing. This will produce a more cost-effective design and result in a balanced design free of transport limitations.