电Fenton方法处理六氯苯污染沉积物工艺参数研究

采用正交试验方法对六氯苯污染的沉积物进行了电Fenton修复研究,分析了各影响因素的显著性水平。在此基础上利用Matlab软件进行了响应曲面和回归分析,探讨了各影响因素分别对HCB的去除率影响程度;确定了电Fenton修复的最佳工作条件:以不锈钢片为电极,处理135gHCB污染沉积物,H2O2(30%V/V)投加量5mL电极间距为6cm,在外加电压13.43V,电解质NaCl投加量5.30g,初始pH值为1.98,经过2h的处理后,六氯苯去除率可达70.9%。     

火焰原子吸收法测定痕量重金属有关问题的探讨

通过实验探讨了火焰原子吸收法测定痕量重金属的最佳条件和消除干扰液的使用,为准确测定其含量,提供了很好的经验。     

海洋环境氯离子沉降率及腐蚀严酷度评价研究

目的 通过大气环境氯离子沉降率和严酷度评价研究,为海水抽水蓄能电站设备防腐蚀设计提供数据支撑.方法 主要利用干片法和银测试片法对海南某地区远海a点和近海b点3—6月大气中的氯离子沉降率和腐蚀速率进行研究.结果 干片法数据分析发现,每月b点氯离子沉降率高于a点,其平均温度低于a点,平均相对湿度高于a点.银片数据分析发现,...     

氨氮实验室空白偏高的影响因素研究

利用排除法对影响氨氮实验室空白测定的各种因素进行了考察。结果表明,固定剂硫酸的添加不会引起空白值偏高。滤纸因含有铵盐会引起空白偏高,但可采取用去离子水浸泡的方法消除。絮凝沉淀过程中应避免将水体pH调至9.0左右。在水体pH=9.0左右时,沉淀物颗粒尺寸最小,过滤时渗入滤后液中,影响吸光度;过滤后的滤液pH会降低,导致滤液中重新析出沉淀物,也影响吸光度。     

微污染原水处理的吸附和沉淀以及预涂过滤一体化技术

集成膨润土吸附与硅藻土预涂膜过滤技术为一体处理微污染源水,同时在内部引入沉淀单元,在单一设备中实现了膨润土吸附、沉淀、过滤三位一体的目的.研究结果表明,吸附-沉淀-分离一体化技术有效地延缓了硅藻土预涂膜过滤时水头损失的上升速度,和原有的吸附预涂膜分离一体化技术相比,有效延长了运行周期,同时,微污染源水有机污染物的去除效果得到显著提高,表明该技术对于微污染源水的处理具有良好的应用前景.     

电解预处理-UASB-CASS工艺处理糠醛废水

对电解预处理-UASB-CASS工艺处理糠醛废水进行了研究,通过试验确定了电解预处理阶段主要影响因素为电流强度大小和电解时间,极板间距对COD去除率影响不大;电解预处理最佳工艺参数为:电流强度0.3 A,电解时间4 h,极板间距30 mm.在此条件下COD去除率为20.6%,废水可生化性提高了38.1%.加上后续的UASB-CASS工艺,出水COD浓度＜150 mg/L,满足《污水综合排放标准》(GB8978-1996)二级排放标准.     

絮凝沉淀-生物接触氧化法处理洗毛废水

针对羊毛脂较低的原料,采用絮凝沉淀-生物接触氧化工艺处理洗毛废水.本文介绍了该工艺的设计参数和运行情况.监测结果表明,其运行效果稳定,出水水质达到《污水综合排放标准》(GB 8978-1996)二级排放标准.     

Bridging the gap between laboratory experiments and naturally occurring markets: An inferred valuation method

Several recent studies have found important differences between behavior in the laboratory and the field. We explore two possible causes for the divergence: social concerns and unfamiliarity with the traded good. Consistent with our conceptual model, we find that people overstated their preferences for relatively familiar goods with normative attributes and understated their preferences for a relatively unfamiliar good with low normative motivations in the laboratory as compared to the field. We also find that for goods with a normative dimension, a new method we refer to as inferred valuation has the potential to narrow the lab–field gap. In some cases, willingness-to-pay obtained from a conventional valuation elicitation method is more than twice the value from the new inferred valuation approach.     

Adsorption distribution impact on preferential transport within horizontal flow constructed wetland (HFCW)

Predicting preferential water flow and solute transport in soils is in the interest of scientists and engineers in the fields of agricultural soil, forest hydrology, soil physics and wastewater treatment by constructed wetland. In artificial wetlands, any preferential pathway induces an insufficient residence time of pollutants in the soil, making an incomplete and unfinished biodegradation process, a wrong evaluation of the hydraulic residence time of the system which would hinder its management in a complete system with several entities of treatment and a non-homogeneous growth of the biofilm in the solid filter mass. This paper is a contribution in tracer experiment data analysis within a horizontal flow constructed wetland built in a storm water basin. A two-dimensional numerical model was used to simulate flow and reactive solute transport. The flow model was successfully calibrated in very dry soil conditions. The adsorption profiles used in the reactive transport modeling are those of five molecules: metolachlor, atrazine, deethylatrazine (DEA), deisopropylatrazine (DIA), and hydroxyatrazine (HA). We show that the adsorption distribution is an internal factor of soil which is responsible to the “preferential” pathway transport in a homogeneous gravel texture. The mean residence time of pollutants within the filter is strongly correlated with the average value of the adsorption coefficient. Moreover, we note a lack of significant impact of the heterogeneity of the medium on the statistical moments of breakthrough curve. It appears that a uni-modal breakthrough curve is not significant to the absence of preferential flow in the medium and at least a two-dimensional display can provide sufficient evidence on the presence or absence of preferential pathways. Finally, using a PLS regression, it is possible to perfectly discriminate the number of peaks of concentration and the asymmetry of the breakthrough curve.     

Buying Time: Real and Hypothetical Offers

This article provides the results of a field test of contingent valuation estimates within a willingness to accept framework. Using dichotomous choice questions in telephone–mail–telephone interviews, we compare survey respondents' responses to real and hypothetical offers for the opportunity to spend time in a second set of interviews on an undisclosed topic. Five hundred and forty people were randomly split between the real and hypothetical treatments. Our findings indicate no significant differences between people's choices with real and hypothetical offers. Choice models werenotsignificantly different between real and hypothetical offers.