Biota–sediment accumulation factor (BSAF), bioaccumulation factor (BAF), and contaminant levels in prey fish to indicate the extent of PAHs and OCPs contamination in eggs of waterbirds

Samples of pond sediment, fish, and shrimp were collected from the Ramsar site at Mai Po marshes, Hong Kong (south China), and samples of pond sediment, fish, and shrimp, as well as eggs of water birds (Chinese Pond Herons (Ardeola bacchus) and Little Egrets (Egretta garzetta)), were collected from two smaller wetland sites at Jiangsu Province (mid-China), between 2004 and 2007. Accumulation levels of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the biota were used to calculate biota–sediment accumulation factor (BSAF) and bioaccumulation factor (BAF). For fish and shrimp, BSAFs of OCPs (3.8–56) were greater than those of PAHs (0.12–6.3). BSAFs and BAFs of 11–79 and 4–34, respectively, were registered for OCPs in eggs of the birds and were greater than those for PAHs (0.11–1.5 and 0.02–1.3, respectively). Assuming that fish were the main prey of the birds, greater bioaccumulation of OCPs was detected for both bird species (BAFs?=?4.5–34), while accumulation of PAHs was only detected in Little Egret (BAF?=?1.3). A significant linear relationship (p?<?0.01) was observed between concentrations of OCPs in bird eggs and in the prey fish. The present study provides a new possibility of using OCP levels detected in prey fish to predict the extent of OCPs contamination in eggs of waterbirds including the endangered species, as a noninvasive method.     

Residue determination and dissipation of ioxynil octanoate in maize and soil

A simple and efficient residue analysis method for direct determination of ioxynil octanoate in maize and soil was developed and validated with High Performance Liquid Chromatography-Ultra Violet (HPLC-UV). The samples were extracted with mixtures of acetonitrile and deionized water followed by Solid Phase Extraction (SPE) to remove co-extractives prior to analysis by HPLC-UV. The recoveries of ioxynil octanoate extracted from maize and soil samples ranged from 86 %–104 % and 84 %–96 %, respectively, with relative standard deviation (RSD) less than 7.84% and sensitivity of 0.01 mg kg^?1. The method was applied to determine the residue of ioxynil octanoate in maize and soil samples from experimental field. Data had shown that the dissipation rate in soil was described as pseudo-first-order kinetics and the half-life (t_1/2) was less than 1.78 days. No ioxynil octanoate residue (<0.01 mg kg^?1) was detected in maize at harvest time withholding period of 60 days after treatments of the pesticide. Direct confirmation of the analytes in field trial samples was realized by Liquid Chromatography-Mass Spectrometry (LC-MS).     

Removal of algal blooms from freshwater by the coagulation–magnetic separation method

This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation–magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe₃O₄). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L^?1). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic–coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups.     

Aquatic plant debris improve phosphorus sorption into sediment under anoxic condition

The effects of plant debris on phosphorus sorption by anoxic sediment were investigated. Addition of plant debris significantly enhanced the decrease of soluble relative phosphorus (SRP) in overlying water at both 10 and 30 °C during the 30-day investigation. Both cellulose and glucose, two typical plant components, also clearly enhanced the SRP decrease in anoxic overlying water. The measurement of phosphorus (P) fractions in sediment revealed that the levels of unstable P forms were decreased by plant debris addition, whereas the opposites were true for stable P forms. However, under sterilized condition, plant debris/glucose addition has no effect on the SRP decrease in overlying water. Overall, our results suggested that plant debris improve P sorption into sediment under anoxic condition through a microorganism-mediated mechanism.     

玉裂废水粘度对二氧化锰臭氧催化氧化处理特性的影响

通过FT-IR和GC—MS检测分析,表明了压裂废水中有机物主要以苯环结构为主的芳香类化合物和其他杂环化合物,苯环及杂环上的主要官能团包括酮、酯、羧酸、醛、酚、氨基等。同时,压裂废水中的粘度为常规水粘度的2～3倍。针对压裂废水高粘度和高COD污染水质特征,实验研究了压裂废水二氧化锰臭氧催化氧化处理特性以及粘度对处理效果的影响,研究结果表明,在粘度较高（2．2×10-3 Pa·s）压裂废水中,投加的化学药剂很难扩散,羟基自由基·OH的利用效率较低,处理效果较差。通过投加过硫酸钾（5g／L）降粘后,可在很大程度上提高二氧化锰臭氧催化氧化的处理效果。通过对压裂废水中有机物分子量分布、FT-IR分析以及GC—MS分析可知,二氧化锰臭氧催化氧化处理压裂废水是通过激发羟基自由基,破坏水中有机物极性和有机物化学构造,将复杂长链有机物转变为简单有机物,其出水COD可达到国家污水综合排放标准中的二级排放标准。     

典型危险废物的工程力学特性

掌握填埋废物的工程力学特性是确保危险废物填埋堆体稳定性的重要前提条件,因此,针对6种典型危险废物的工程力学特性开展了调查研究.研究结果表明,污泥类危险废物的含水率和有机质含量远高于非污泥类危险废物,而前者的比重则显著低于后者.污泥类危险废物的渗透系数相对较小,比污染土壤和飞灰炉渣混合物的渗透系数小1个数量级,比滤池填料的渗透系数小2个数量级.不同危险废物的无侧限抗压强度排序为:飞灰炉渣混合物(314.3 kPa)和滤池填料(278.9 kPa)＞污染土壤(124.9 kPa)＞杭州氧气厂污泥(68.6 kPa)、锌铬污泥(71.4 kPa)、油泥(58.4 kPa).不同危险废物的粘聚力排序为:飞灰炉渣混合物(40.8 kPa)、滤池填料(31.1 kPa)＞污染土壤(20.9 kPa)＞杭州氧气厂污泥(1.94kPa)、锌铬污泥(3.10 kPa)、油泥(1.81 kPa).此外,不同危险废物的内摩擦角差异相对较小,其变化范围在18.8°～35.0°之间.综合分析可知,飞灰炉渣混合物和滤池填料的工程力学特性较好,而污泥类危险废物的工程力学特性则较差.     

低浓度含砷污酸处理工艺的比较研究

比较研究了石灰中和法和石灰-铁盐法对硫化后含低浓度砷(20～50 mg/L)污酸的处理效果。结果表明,单纯采用石灰法,废水难以达标排放;而两段石灰-铁盐(氯化铁)法满足达标排放的同时,一段及二段沉淀物的浸出液中砷、镉、铜、铅和锌含量均低于危险废物鉴别标准要求(GB 5085.3-2007);其最优工艺参数为一段终了pH=2,反应时间为2 h,二段终了pH=8、Fe/As=8、反应时间为60 min、氧化剂投加量(Ca(ClO)2/As)为6∶1;正交实验结果中各参数对铁盐除砷效果影响顺序为终了pH>反应时间>Fe/As>氧化剂投加量。     

不同碳源添加量对垂直流人工湿地污水处理效果的影响

以垂直流人工湿地小试系统为研究对象,采用碱处理过的千屈菜(Lythrum salicaria)作为反硝化碳源补充材料,探讨了不同碳源添加量对系统COD及氮、磷去除效果的影响。结果表明,一定剂量经过碱处理的千屈菜材料可以为人工湿地系统脱氮提供反硝化所需要的碳源,而且具有缓效持续释放的特点。添加此碳源材料可明显提高系统的脱氮效率,最高可提升30.85%,但随着C/N比的增加,硝态氮去除率逐渐降低,C/N比为3、5、8时分别为91.20%、87.72%和84.19%。添加碳源量达到C/N比为3时系统能够发生最大程度反硝化,此时不仅人工湿地系统脱氮效果得到提高,同时人工湿地除磷能力也有所增强。碱处理过的千屈菜材料在本系统中的最适宜添加量为5 g,即100 g/m2(C/N=3),远低于在进水中为满足反硝化所需调控的C/N比(5～8),可以节约外加碳源成本。     

KMnO4缓释剂的释放性能及其在垃圾渗滤液处理中的应用

为延长KMnO4在地下水原位修复中的作用时间,通过改变KMnO4与石蜡的分散方式以及KMnO4与石蜡的质量比(P/W),对KMnO4缓释剂的制备过程进行了优化.采用超声与搅拌联用(搅拌速度150 r/min)的分散方式更有利于KMnO4的均匀分布,随着P/W的升高,KMnO4负载量逐渐增大而绝对回收率逐渐减小.静态实验分别研究了缓释剂在8℃、不同pH与DO浓度下的释放性能.结果表明,在8℃环境下,缓释剂仍具有释放性能;缓释剂受pH影响较大而受DO浓度影响较小.利用缓释剂降解垃圾渗滤液中的COD以及对沉淀物进行定量分析.结果表明,缓释剂对COD去除率可高达57.1％,而沉淀量最少仅为投加纯KMnO4的8.5％.     

压裂废水粘度对二氧化锰臭氧催化氧化处理特性的影响

通过FT-IR和GC-MS检测分析,表明了压裂废水中有机物主要以苯环结构为主的芳香类化合物和其他杂环化合物,苯环及杂环上的主要官能团包括酮、酯、羧酸、醛、酚、氨基等。同时,压裂废水中的粘度为常规水粘度的2~3倍。针对压裂废水高粘度和高COD污染水质特征,实验研究了压裂废水二氧化锰臭氧催化氧化处理特性以及粘度对处理效果的影响,研究结果表明,在粘度较高(2.2×10^-3Pa·s)压裂废水中,投加的化学药剂很难扩散,羟基自由基·OH的利用效率较低,处理效果较差。通过投加过硫酸钾(5 g/L)降粘后,可在很大程度上提高二氧化锰臭氧催化氧化的处理效果。通过对压裂废水中有机物分子量分布、FT-IR分析以及GC-MS分析可知,二氧化锰臭氧催化氧化处理压裂废水是通过激发羟基自由基,破坏水中有机物极性和有机物化学构造,将复杂长链有机物转变为简单有机物,其出水COD可达到国家污水综合排放标准中的二级排放标准。