Research on heavy metal release with suspended sediment in Taihu Lake under hydrodynamic condition

Heavy metals are often stored in the sediment of lakes or reservoirs and are easily released to the overlying water in the case of strong wind, which greatly affects the water environment of lakes or reservoirs. The conventional investigation of heavy metals in lakes has been relatively extensive, but there is no numerical model for heavy metals released into overlying water with suspended sediment under hydrodynamic action. In this paper, laboratory experiments were carried out, and it is found that the concentration of heavy metals (Cr, Cu, Cd) often begins to stabilize after the concentration of total suspended solids (TSS) reaches a stable level. With the increase of flow velocity (3.2 to 14 cm/s), the final equilibrium concentration of TSS, Cr, Cu, and Cd will also increase from 174 to 1102 mg/L, 0.72 to 1.14 mu g/L, 2.34 to 10.45 mu g/L, and 0.13 to 0.35 mu g/L, respectively. Based on lattice Boltzmann method (LBM), a numerical model of heavy metal released into overlying water under hydrodynamic conditions is established. Compared the simulated data with measured data, the average R-2 of LBM model can be reached at 0.827, higher than 0.711 of traditional simulation model. The development of the numerical model is conducive to the prediction of lake or reservoir environment and also provides a theoretical basis for heavy metal treatment in reservoirs.

Automated summary

This paper investigates the release of heavy metals into overlying water under hydrodynamic conditions in lakes. Experimental results show that the concentration of heavy metals is closely related to the concentration of total suspended solids and is influenced by flow velocity. A numerical model based on lattice Boltzmann method is established, and it outperforms traditional simulation models in terms of accuracy. This research contributes to the prediction of lake environments and provides a theoretical basis for heavy metal treatment in reservoirs.