Identifying the Key Parameters in Mathematical Model to Simulate the Main Nutrients Transformation Process in Vietnamese Catfish (pangasianodon hypophthalmus) Ponds ☆

Pangasius farming is a process that involves putting a large amount of material into the pond but then only harvesting a small amount of farmed fish, the rest is waste put into the aquatic environment. Pangasius farming can lead to water pollution, the main reason for the deterioration of the water environment in the rivers and canals of the Pangasius farming area. Establishing a mathematical model to simulate the nutrient transformation processes in the pond is necessary. This study aims to set up a mathematical model to simulate the change in the composition of major nutrients in Pangasius ponds to determine the key parameters that affect the model and maximize the culture regime and help improve fish quality and minimize environmental impact. The results have shown that model output data after calibration are relatively close to reality and the key parameters of the model were defined with value as: VPsettling = 0.5; 0.4, FBMPOC(i) = 0.7, KrefrespDOC = 0.01, kfo = 0.493, kfn = 0.025, Ψ(i) = 0.65, nitrifmax = 0.85, kfp = 0.001277, Kreaeration = 2.4.