Research on the adsorption rule of porous media on supersaturated total dissolved gas

Abstract

Discharge of high dams may result in supersaturated total dissolved gas (TDG) in water, which could cause fish that live downstream river to suffer from gas bubble disease. If supersaturated TDG water was taken as a water source for breeding and proliferation stations, farmed fish was confined and may face more severe problems than fish living in the river. Therefore, it is critical to develop strategies to reduce the negative effects of supersaturated TDG. In this research, the adsorption effect of porous media on supersaturated TDG was explored, including biofilter adsorption experiments and previously existing activated carbon adsorption experiments. The experimental results showed that adding porous media to the water effectively accelerated the dissipation of supersaturated TDG, and the adsorption effect was associated with the specific surface area, mass density, and initial TDG saturation. To quantitively evaluate the adsorption effects of the porous media, the porous adsorption coefficient was proposed to express the adsorption rate of porous media on supersaturated TDG. The porous adsorption coefficient was related to the initial TDG saturation and the specific surface area of the porous media. The porous adsorption coefficient increased with increasing the specific surface area and decreasing initial TDG saturation. Based on this, an equation related to the specific surface area, initial TDG saturation, and the porous adsorption coefficient was developed. This equation may be used to evaluate the adsorption effect of porous media on supersaturated TDG. This study could serve as a crucial resource in reducing the adverse impacts of supersaturated TDG.