潜水式生态介质箱的优化设计及其修复黑臭水体的效果比较研究

第一代潜水式生态介质箱(装置组)能修复深层黑臭水体,但其对下层水体溶解氧的增加能力有限。本文在现有第一代生态介质箱的基础上增设水下深层化学增氧器并更换环境矿物基质,视为第二代生态介质箱(联合组),分别以未经任何处理的水样(空白组)、将沉水植物种植在底泥上(苦草组)作为对照,比较了联合组、装置组、苦草组修复黑臭水体的效果,及其对苦草生长生理的影响。结果表明,装置组和联合组的各项水质指标远优于空白组和苦草组,联合组的DO含量略低于装置组,两组的CODMn去除率无明显差异,而联合组的TN、NH4+-N和TP的去除效果均优于装置组,说明装置组内更换的环境矿物材料和深层化学增氧器有利于水体的净化;此外,以苦草组里的苦草长势最佳,但装置组、联合组、苦草组里的苦草均无叶片发黄和死亡现象发生,其中联合组中苦草的叶绿素a+b和丙二醛(MDA)含量略高于装置组中的,而质膜透性则无明显差异,说明矿物基质和增氧器的更换对苦草的生长影响不大。综上所述,尽管联合组和装置组中的矿物基质对苦草有胁迫作用,但不影响苦草的正常生长,反而有利于水体修复效果的提升,且联合组克服了装置组能耗高、扰动大、水体深层增氧效果差等缺点。以上研究结果可为潜水式生态介质箱的优化及黑臭水体的深层修复等提供技术支持。

Optimal Design of Submersible Eco-medium Box and Its Effect on the Repairing Black and Odorous Water

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 COD_Mn 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 conductive 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.