南通市任港河底泥重金属污染的磁学诊断

以江苏省南通市任港河底泥柱样为研究对象,在系统的环境磁学、粒度、重金属及总有机碳含量分析的基础上,探讨了沉积物重金属污染的环境磁学诊断的可行性.结果表明,表层12cm以上样品中重金属Pb、Zn、Cu、Ni含量超出江苏省土壤背景值,剔除粒度影响后,重金属含量"上高下低"的特征仍很明显.该底泥柱样沉积物的磁性特征为亚铁磁性矿物所主导,亚铁磁性矿物含量在表层12cm以上沉积物要高于下部沉积物,其含量在沉积物上部的升高受到污染的影响.磁化率(χ)、饱和等温剩磁(SIRM)和非磁滞剩磁磁化率(χARM)与Pb、Zn、Cu、Ni含量有显著的正相关关系(r≥0.74,p<0.01,n=54),可用于定性评价任港河底泥的重金属污染程度.但因受到磁性矿物的来源和成岩作用等因素影响,表层沉积物亚铁磁性矿物与重金属含量升高不尽一致,利用磁性参数定量诊断重金属含量仍需慎重.     

Contaminant removal from low-concentration polluted river water by the bio-rack wetlands

The bio-rack is a new approach for treating low-concentration polluted river water in wetland systems. A comparative study of the efficiency of contaminant removal between four plant species in bio-rack wetlands and between a bio-rack system and control system was conducted on a small-scale (500 mm length × 400 mm width × 400 mm height) to evaluate the decontamination effects of four different wetland plants. There was generally a significant difference in the removal of total nitrogen (TN), ammonia nitrogen (NH₃-N) and total phosphorus (TP), but no significant difference in the removal of permanganate index (COD_Mn) between the bio-rack wetland and control system. Bio-rack wetland planted with Thalia dealbata had higher nutrient removal rates than wetlands planted with other species. Plant fine-root (root diameter ≤ 3 mm) biomass rather than total plant biomass was related to nutrient removal efficiency. The study suggested that the nutrient removal rates are influenced by plant species, and high fine-root biomass is an important factor in selecting highly effective wetland plants for a bio-rack system. According to the mass balance, the TN and TP removal were in the range of 61.03--73.27 g/m² and 4.14--5.20 g/m² in four bio-rack wetlands during the whole operational period. The N and P removal by plant uptake constituted 34.9%--43.81% of the mass N removal and 62.05%--74.81% of the mass P removal. The study showed that the nitrification/denitrification process and plant uptake process are major removal pathways for TN, while plant uptake is an effective removal pathway for TP.     

天津北塘排污河沉积物的重金属污染及评价

北塘排污河是天津市海河以北市政污水的主要受纳水体,其污染十分严重。该研究于2009年沿河采集其沉积物,调查重金属Zn、Cu、Cr、Pb、Cd和Hg的污染状况。结果表明,沉积物中这6种重金属沿河呈波浪变化,其中Cu和Zn在西碱河入河口处最高,Pb、Cd和Hg在靖江桥处最高,而Cr在京津高速路桥处最高,其平均含量的大小变化顺序为Zn﹥Cu﹥Cr﹥Pb﹥Cd﹥Hg。采用地质累积指数法和潜在生态风险指数法对其评价表明,这6种重金属的整体污染和潜在生态风险均比较严重,京津高速路桥处污染最为严重;靖江桥处风险等级最高,潜在生态风险最大;就整条河而言,重金属污染程度大小顺序为Cd﹥Hg﹥Cu﹥Zn﹥Pb﹥Cr,而潜在生态风险大小顺序为Cd﹥Hg﹥Cu﹥Pb﹥Zn﹥Cr。     

Effect of artificial aeration on the performance of vertical-flow constructed wetland treating heavily polluted river water

Three lab-scale vertical-flow constructed wetlands (VFCWs), including the non-aerated (NA), intermittently aerated (IA) and continuously aerated (CA) ones, were operated at different hydraulic loading rates (HLRs) to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water. Results indicated that artificial aeration increased the dissolved oxygen (DO) concentrations in IA and CA, which significantly favored the removal of organic matter and NH₄⁺-N. The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen (TN). Although the removal efficiencies of COD_Cr, NH₄⁺-N and TN in the three VFCWs all decreased with an increase in HLR, artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings. The maximal removal efficiencies of COD_Cr, NH₄⁺-N and total phosphorus (TP) (i.e., 81%, 87% and 37%, respectively) were observed in CA at 19 cm/day HLR, while the maximal TN removal (i.e., 57%) was achieved in IA. Although the improvement of artificial aeration on TP removal was limited, this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted river water, particularly at a high HLR.     

淮河下游小流域空间开发功能分区研究-以江苏沿海地区为例

基于区域开发与水环境保护的相互作用关系,以江苏沿海地区某小流域为研究对象,在流域层面上,建立定性与定量相结合,环境、经济、社会紧密结合的区域分析方法。选取水体使用功能、水质目标、清水通道、水体通达性、现状水质达标情况5项指标,将流域分为强约束区、较强约束区、中等约束区、弱约束区4类空间开发功能区。以此为依据,对各分区针对性提出了空间开发和产业发展的导向。其中水环境约束较弱的地区可以适当布局酿造、造纸、化工等水污染物排放量相对较大的产业;水环境约束较强的地区需要严格控制乃至禁止水污染物排放量大的产业,而适度发展编织品制造等不排水的农副产品加工业,或清洁生产水平先进、中水回用率高、排水量小的家具制造、木材加工等。     

BAF-BAC组合工艺对受污染河水水质净化研究

研究通过采用BAF-BAC组合工艺净化受污染河水,进行了该系统对主要污染物指标的去除效果分析,并结合多种生物毒性效应检测,进行了系统对生物毒性物质的去除研究。结果表明:组合工艺系统稳定运行阶段,对COD、NH3-N和TN平均去除率分别在60%、96%和19%左右。试验条件下最适宜水力负荷10 L/h,BAF单元最佳气水比为7:1时,系统对上述污染物的去除率分别达到72%、99%和20%。发光菌抑制试验表明,受污染河水在浓缩50、10和2倍时,相对抑制率均高于80%,经BAF-BAC组合装置净化后,相对抑制率分别为15.8%、7.8%和3%,出水水质没有表现出明显急性毒性特征;受污染河水对大型蚤急性致死率达到100%,而最终出水大型蚤死亡率为0%;在浓缩50倍、20倍、10倍和1倍时,受污染河水水样对仔鱼的致死性分别为100%、70%、20%和0,最终出水水样中仔鱼死亡率均为0,说明组合工艺系统各单元对此类毒性物质均有去除效果。     

城市滞流河道黑臭发生及控制研究

为了研究常州市老城区典型河道—北市河的黑臭现象发生原因,采用自主研发的一套滞流型河道沉积物污染释放与抑制装置,通过综合黑臭指数分析表明黑臭现象的发生耗时很长,由此推断导致水体黑臭发生的主要原因是外源污染物的排入。此外还从曝气深度和净化剂2个方面出发,研究其对黑臭的控制作用。在实验装置中选定距表面50 cm、100 cm、150 cm 3个深度,采用间歇纯氧曝气方式对水体进行处理,水质变化情况表明采用100 cm深度进行曝气对水体黑臭的控制效果最好。在净化剂比选实验中,在实验柱中分别投加商品钝化剂、过氧化氢、过氧化钙,并设置空白对照实验,监测水质参数随时间的变化情况,采用层次分析法进行净化剂的优选,分析结果表明过氧化钙的净化效果最好。     

大辽河感潮河段水体交换的数值研究

基于FVCOM建立大辽河感潮河段的水动力-扩散数值模型,采用保守物质输运扩散法研究大辽河感潮河段在潮和径流作用下的水体交换特征。结果表明:径流是影响大辽河感潮河段水交换的主要因素,径流为114 m3/s条件下,半交换时间为226 h,587 h后达到90%的交换状态,且径流加倍,对应交换时间近似线性递减;子区域水交换差异由潮和径流的相互作用决定,径流越大,靠向上游河段水体交换得越快,径流减小时近河口区段水体交换变快,而中游河段交换变慢。     

山西汾河流域生态修复技术与对策探讨

汾河流域近年来污染严重,其污染治理和生态修复已引起高度重视。通过对汾河中下游流域存在问题的分析和以人工湿地为主的生态修复技术的概述,提出汾河流域的污染治理和生态修复的对策。     

浊漳河山西省潞城市境内段河流生态健康评价研究

浊漳河山西省潞城市境内干流段及南源段河道生态环境目前最突出的问题在于水质恶化、水量减少以及生物多样性衰退。本文从水质、水量、生物状况三个要素出发,通过建立浊漳河潞城市境内河段的水生态健康评价体系,对浊漳南源及干流段进行了生态健康诊断。结果显示,浊漳干流段生态健康总指数36.74,呈生态病态状;南源段生态健康总指数60.03,呈基本健康状态。据此,浊漳河潞城境内段目前的核心问题是生态恢复问题,应当针对其存在的问题选择适当的生态修复模式,采取相应的生态环境管理方法,把生态系统的恢复和重建作为其流域治理的最终目标。