Kinetics of soil ozonation: an experimental and numerical investigation

This study investigates the use of ozone for soil remediation. Batch experiments, in which ozone-containing gas was continuously recycled through a soil bed, were conducted to quantify the rate of ozone self-decomposition and the rates of ozone interaction with soil organic and inorganic matter. Column experiments were conducted to measure ozone breakthrough from a soil column. Parameters such as ozone flow rate, soil mass, and ozonation time were varied in these experiments. After ozone concentration had reached steady state, the total organic carbon concentration was measured for all soil samples. The ozonation efficiency, represented by the ratio of soil organic matter consumed to the total ozone input, was quantified for each experiment. Numerical simulations were conducted to simulate experimentally obtained column breakthrough curves. Experimentally obtained kinetic rate constants were used in these simulations, and the results were in good agreement with experimental data. In contrast to previous studies in which soil inorganic matter was completely ignored, our experiments indicate that soil inorganic matter may also promote depletion of ozone, thus reducing the overall ozonation efficiency. Three-dimensional numerical simulations were conducted to predict the efficacy of ozonation for soil remediation in the field. These simulations indicate that such ozonation can be very effective, provided that effective circulation of ozone is achieved through appropriately placed wells.     

三维电极-Fenton试剂耦合法去除废水COD实验研究

以对苯二酚模拟废水为处理对象，研究了三维电极-Fenton试剂耦合法，并对三维电极法、Fenton法及三维电极-Fenton试剂耦合法去除废水COD的效率进行了对比，结果表明，三维电极-Fenton试剂耦合法处理效率明显高于普通Fenton法和三维电极法。且最佳工艺条件下，三维电极-Fenton试剂耦合法对模拟对苯二酚废水COD去除率可达92．03％。     

Detection of geosmin and 2-methylisoborneol by liquid-liquid extraction-gas chromatograph mass spectrum (LLE-GCMS) and solid phase extraction-gas chromatograph mass spectrum (SPE-GCMS)

Two sample preparation methods were introduced and compared in this paper to establish a simple, quick and exact analysis of geosmin and 2-methylisoborneol. LC-18 column was employed in solid phase extraction (SPE), 1.0 mL of hexane was adopted in liquid-liquid extraction (LLE), and the extracts were analyzed by gas chromatograph mass spectrum (GCMS) in selected ion mode. Mean recoveries of SPE were low for 2-methylisoborneol (2-MIB) and geosmin (GSM) with values below 50%. For LLE, the recoveries were satisfyingly above 50% for 2-MIB and 80% for GSM. Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB. A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer, there was a serious odor problem induced by a high concentration of 2-MIB. The highest concentration of 152.82 ng/L appeared in July in raw water, while GSM flocculation was minimal with concentrations below odor threshold.     

模拟纳污水体底质参数变化

本文介绍了模拟纳污水体中ＷＡＲ，ＷＭＲ，ＷＣＨ，ＳＡＲ，ＳＭＲ，ＳＳＦ和ＲＯＣ的变化。过程曲线表明水体污染时底质参数出现累积现象。     

喀什地区农村改水后饮水状况研究

喀会地区农村改水后，水质仍较差，饮用符合Ⅰ、Ⅱ、Ⅲ级水及饮用水不合格水的人数的百分比分别是５．４％、９．９％、２６．０％和５４．１％。     

Practical field application of a novel BOD monitoring system

A biochemical oxygen demand (BOD) monitoring system, based on electrochemically-active bacteria in combination with a microbial fuel cell, has been developed for the purpose of on-site, on-line and real-time monitoring of practical wastewater. A microbial fuel cell that had been enriched with electrochemically-active bacteria was used as the basis of the measurement system. When synthetic wastewater was fed to the system, the current generation pattern and its Coulombic yield were found to be dependent on the BOD5 of the synthetic wastewater. A linear correlation between the Coulombic yields and the BOD5 of the synthetic wastewater were established. Real wastewater obtained from a sewage treatment plant also produced a highly linear correlation between the Coulombic yield and BOD5 in the system. To examine on-site, on-line and real-time monitoring capability, the BOD monitoring system was installed at a sewage treatment plant. Over 60 days, the measurement system was successfully operated with high accuracy and good stability with the measuring period for a sample being 45 min. This application showed that the application of the measurement system was a rapid and practical way for the determination of BOD5 in water industries.     

Physicochemical factors affecting the sensitivity of Ceriodaphnia dubia to copper

The effects of physicochemical conditions, such as pH, water hardness, flow rates and natural organic substances on the sensitivity of Ceriodaphnia dubia to the toxic effects of copper were investigated using static bioassay cups and specially designed flow-through bioassay chambers. We found that C.dubia was very sensitive to pH changes and the total copper LC50 values of C. dubia neonates increased by 15-fold as the pH increased from pH 7 to 10. It was also observed that the LC50 values increased sharply upon increasing the water hardness value to 2.4 meq. In addition, increasing flow rates from zeroto 50 mL hr^-1 also increased its sensitivity to copper, which was possibly due to hydrodynamic stress.The presence of natural organic substances (humic acid and dissolved organic matter) and suspended particles decreased thetoxic effect of copper. This significant decrease in the toxicity of copper in the presence of natural organic materialscan be explained by a reduction in the free ion concentration due to complexation. Furthermore, we observed that the kinetics of copper interactions with natural organic materials are a significant factor in the toxic effect of copper and that the acute LC50 values increased with increasing reaction time betweensolubilized copper and water-borne organics.     

Phosphine production in anaerobic wastewater treatment under tetracycline antibiotic pressure

The influence of tetracycline(TC) antibiotics on phosphine(PH_3) production in the anaerobic wastewater treatment was studied. A lab-scale anaerobic baffled reactor with three compartments was employed to simulate this process. The reactor was operated in a TC-absence wastewater and 250 μg/L TC-presence wastewater for three months after a start-up period,respectively. The responses of p H, oxidation–reduction potential(ORP), chemical oxygen demand(COD), total phosphorus(TP), enzymes activity(dehydrogenase and acid phosphatase),and microbial community were investigated to reveal the effect of TC on PH_3 production.Results suggested that the dehydrogenase(DH) activity, acid phosphatase(ACP) activity and COD have positive relationship with PH_3 production, while p H, ORP level and the TP in liquid phase have negative relationship with PH_3 production. With prolonged TC exposure, decrease in p H and increase in DH activity are beneficial to PH_3 production, while decrease in COD and ACP activity are not the limiting factors for PH_3 production.     

分子筛在铅污染土壤修复中的应用研究

采用溶液试验,从待选钝化材料中初步筛选出对Pb具有较好钝化效果的钝化材料,运用经典混料设计的试验方法,将优选出的13X分子筛、凹凸棒土、粉煤灰三种钝化材料复配成钝化剂,添加到Pb含量为1 500mg/kg的污染土中,添加量为污染土的20％,并保持土壤的含水率35％,3天后取钝化后土壤,采用(HJ/T 300-2007)(固体废物浸出毒性浸出方法醋酸缓冲溶液法)测其浸出液中的重金属Pb含量,采用Minitab软件对混料设计试验数据进行处理,优选出钝化重金属Pb的最佳钝化剂配方:分子筛25％,凹凸棒土42.6％,粉煤灰32.4％,钝化后浸出液中重金属Pb含量为0.027 1 mg/L,明显低于地表水质量标准的Ⅲ类标准0.05 mg/L.     

基于两高司法解释的突发环境事件应急监测风险管理的思考

突发环境污染事故的发生,往往伴随着环境违法行为,因此突发性环境污染监测涉刑的可能性更大.因此环境监测站在实施突发性环境污染事件监测工作时,在环境监测环节及时收集可能的违法证据,形成证据链,为复现环境污染事件提供证据,为司法界入及时提供技术支持.根据风险管理原则,采用矩阵法对涉刑下的突发性环境事件应急监测进行了风险事件识别和风险评价,详细地对涉刑情形下的突发性环境事件应急监测进行环境分析,并提出了相应的风险应对措施,为环境监测系统防范和规避风险提供参考.