YANG Na, WANG Chenyi, XU Yuanyuan, ZHENG Yu, LI Yuan, CHEN Zilin
(College of Biology and Environment, Zhejiang Wanli University, Ningbo, 315100, China)

Abstract: The first-generation submersible eco-medium box (device group) can repair deep black and odorous water bodies, but its ability to increase dissolved oxygen in the lower water is limited. The second-generation added a deep underwater chemical oxygenator to the first-generation submersible eco-medium box and replaced the internal minerals, thus, is referred to combined group. Take the water samples without any treatment (blank group) and plant the submerged plants (Vallisneria) on bottom mud as a control (Vallisneria group) to compare the effects of the combined group and the device group on the repairing black and odorous water bodies, and the influence on the growth and physiology of Vallisneria. The results show that the water quality indicators of the device group and the combined group were better than those of the blank group and the Vallisneria group. Compared with the device group, the DO content of the combined group was slightly lower than that of the device group, and there was no significant difference in CODMn removal rate between the two groups. The removal effects of TN, NH4+-N and TP by the combined group were better than those of the device group, and it shows that the environmental mineral materials and deep chemical oxygenator are conducive to the purification of water bodies. Besides, the Vallisneria in the Vallisneria group grew best, however, there was no plant died and no leaves become yellow in the device group, in the combined group, and in the Vallisneria group. Among them, the content of chlorophyll a+b and malondialdehyde (MDA) in the combined group was slightly higher than that in the device group, but there was no significant difference in plasma membrane permeability, and it shows that the replacement of the mineral substrate and aerator has little effect on the growth of Vallisneria. To sum up, although the mineral matrix in the combined group and the device group is stressful to the Vallisneria, it does not affect the normal growth of Vallisneria, and it is useful to improve the water body restoration, and the combined group overcomes the shortcomings of high energy consumption, large disturbance, and poor effect of increasing oxygen in deep water bodie. This research provides technical support for the design optimization of submersible eco-medium box and for the deep restoration of black and odorous water bodies.

Key word: black and odorous water bodies repair; submersible eco-medium box; underwater deep chemical oxygenator; pollution remediation effect; the growth physiology of Vallisneria

EARTH AND ENVIRONMENT Vol.49, No.4, Tot No.342, 2021, Page 447-454