Zhu Lin, Li Xun, Zhang Chen, Duan Zengqiang
State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science, Chinese Academy of Sciences 71 East Beijing Road, Nanjing 210008, China.
Int J Environ Res Public Health. 2017 Apr 1;14(4):374. doi: 10.3390/ijerph14040374.
Heavily polluted sediment is becoming an important part of water pollution, and this situation is particularly acute in developing countries. Sediment has gradually changed from being the pollution adsorbent to the release source and has influenced the water environment and public health. In this study, we evaluated the pollutant distribution in sediment in a heavily polluted river and agitated the sediment in a heavily polluted river to re-suspend it and re-release pollutants. We found that the levels of chemical oxygen demand (COD), NH₄⁺-N, total nitrogen (TN), and total phosphorus (TP) in overlying water were significantly increased 60 min after agitation. The distribution of the pollutants in the sediment present high concentrations of pollutants congregated on top of the sediment after re-settling, and their distribution decreased with depth. Before agitation, the pollutants were randomly distributed throughout the sediment. Secondly, deep sediment aeration equipment (a micro-porous air diffuser) was installed during the process of sedimentation to study the remediation of the sediment by continuous aeration. The results revealed that deep sediment aeration after re-suspension significantly promoted the degradation of the pollutants both in overlying water and sediment, which also reduced the thickness of the sediment from 0.9 m to 0.6 m. Therefore, sediment aeration after suspension was efficient, and is a promising method for sediment remediation applications.
重度污染的沉积物正成为水污染的重要组成部分，这种情况在发展中国家尤为严重。沉积物已逐渐从污染吸附剂转变为释放源，并对水环境和公众健康产生了影响。在本研究中，我们评估了一条重度污染河流中沉积物的污染物分布情况，并对该河流中的沉积物进行搅动使其重新悬浮，进而重新释放污染物。我们发现，搅动60分钟后，上覆水中的化学需氧量（COD）、铵态氮（NH₄⁺-N）、总氮（TN）和总磷（TP）水平显著升高。沉积物中污染物的分布情况是，重新沉降后，高浓度污染物聚集在沉积物顶部，且其分布随深度降低。搅动前，污染物在整个沉积物中随机分布。其次，在沉积物沉降过程中安装了深层沉积物曝气设备（微孔空气扩散器），以研究通过持续曝气对沉积物进行修复的效果。结果表明，重新悬浮后的深层沉积物曝气显著促进了上覆水和沉积物中污染物的降解，沉积物厚度也从0.9米减至0.6米。因此，悬浮后进行沉积物曝气是有效的，是一种很有前景的沉积物修复应用方法。
