Modeling re-oxygenation performance of fine-bubble–diffusing aeration system in aquaculture ponds

Fine-bubble-diffusing (FBD) aeration system is widely used in aquaculture ponds. To maximize its re-oxygenation capability, it is needed to have a quantitative understanding of the reoxygenation performance. In practice, two indexes, namely oxygen volume mass transfer coefficient (KLa) and standard oxygen transfer efficiency (E), are commonly used to measure the re-oxygenation performance. However, few mathematical models are available to accurately predict these two indexes. The objective of this regard was to develop such a model driven by commonly available data. In this regard, the results from 54 group laboratory tests were regressed on four independent variables, including air flow rate (Qg), aeration tube length (L), submerged water depth of the diffuser (hd), and plane-view tank area (Acs). The regression revealed that both KLa and E are negatively related to hd and Acs, but they are positively related to L. In addition, KLa was found to be positively related to Qg, whereas E was found to be negatively related to Qg. Two regression models, one for KLa while another for E, are expected to be effective tools for operating FBD aeration system in practice to maximize its re-oxygenation capability though they may need to be further verified using field data.