不同覆盖层对生物滞留系统运行特性的影响

覆盖层可有效减少雨水径流中的悬浮物(TSS)对种植层填料的阻塞。对于高TSS含量的道路雨水径流而言,在生物滞留设施中构建覆盖层可延缓填料的阻塞,并避免表层土壤发生板结而造成滞留设施渗透性能的降低。研究采用椰丝(CC)、沸石(ZE)、火山岩(SC)等3种材料作为覆盖层,考察其对滤柱水力性能及其除污特性的影响,并采用递阶层次模型对不同滤柱性能进行层次分析评估,以确定具有耐堵特性且较优除污性能的覆盖层构造。结果表明,ZE和CC作为覆盖层时,滤柱的水力性能在试验期内持续下降;SC组的渗透系数稳定在(72±9.9) mm/h,滤料层表现出良好的耐堵塞特性,并具有较优的除污性能,对TSS、COD、NH~+_4-N、TN、NO~-_3-N和TP的去除率(中位数)分别可达99.8%、72.6%、99.7%、87.1%、89%和98.1%。生物滞留设施的最佳覆盖层构造为进水区采用CC,而非进水区采用SC。     

基于不同疏浚绞刀结构的底泥污染物释放情况分析

分别采用普通绞刀、加罩普通绞刀、螺旋绞刀和加罩螺旋绞刀进行疏浚模拟试验,通过比较疏浚点周围上覆水中各污染物浓度变化情况,分析不同结构绞刀的环保性能。结果表明:采用螺旋绞刀疏浚下,底泥中污染物释放量较采用普通绞刀疏浚时小;在这两类绞刀上加装罩壳均能有效抑制底泥中污染物释放,特别是疏浚后1h内营养盐氮释放;理想的绞吸式挖泥船环保功能改造方案为采用螺旋绞刀替换普通绞刀并加装罩壳(防扩散装置)。     

Application of Improved Comprehensive Water Quality Marking Index Method in Water Quality Evaluation of Pearl River EstuaryEI北大核心CSCD

To study the characteristics of water quality variation in the Pearl River Estuary during the recent years, the water quality in the Pearl River Estuary is evaluated and the tempo-spatial distribution characteristics of water quality is analyzed, based on data from 51 monthly collected water quality sampling points from 2018 to 2020, with evaluation indices filtered using principal factor analysis and improvement on traditional comprehensive water quality identification index method using combinatorial integration method.Results show that the comprehensive water quality identification index method combined with combinatorial integration method takes both excessive pollutants index and other indices into account, so as to obtain reasonable and reliable results, which means the method is suitable for large-scale watershed water quality assessment. The water qualities in all drainages tend to improve over the years, mainly from class of inferior Ⅴ to Ⅲ, which met the water quality goals in water environment function zones. The water quality in the western regions was slightly worse than that in the eastern regions.The river water quality in the Nanshan district was better than that in the Dakonggang district, however the improvement in river water quality in Dakonggang and Qianhai district was more significant. The water quality of the upstream was generally better than that of the downstream. Estuary water quality fluctuates greatly with the seasons, which was generally affected by sea water pollution and the tidal sluice operations. © 2022, Editorial Board of Water Resources Protection. All rights reserved.