酚类内分泌干扰物的污染现状及处理研究进展

为了更好的治理水体中pEDCs的污染,针对pEDCs的代表物质双酚A和烷基酚,综述了世界范围内污染源水中pEDCs的污染现状,并介绍了吸附法、膜处理法、生物降解法、化学氧化法及高级氧化法等主要处理方法。同时,展望了今后pEDCs处理的主要研究方向及现存处理方法的应用前景。两种或两种以上方法的联用将是未来研究的一个重要方向。     

自动消解仪-ICP法测定土壤中7种重金属离子实验研究

利用自动消解仪对土壤进行前处理,建立了电感耦合等离子体发射光谱法(ICP-OES)同时测定Cu、Zn、Ni、Cr、Sr、V、Co七种重金属元素含量的方法。该方法的相关系数均在3个9以上。测定了国家标准物质GBW07429土壤中的元素,测定值与标准值一致,相对标准偏差1.6%~4.5%,检出限0.000 2~0.005 mg/L。利用建立的方法测定了天津市土壤中的七种重金属元素含量,为土壤中重金属元素含量的测定提供了简单可靠的分析方法。     

Determination of optimum operating conditions for industrial dye wastewater treatment using adaptive heuristic criticism pH control

For a pilot-scale application, pH control in the treatment of highly contaminated dye industrial wastewater containing metallic compounds as the main pollutants has been investigated with a method using adaptive heuristic criticism control (AHCC). Subsequent experimentation on between 12 and 18 l of the wastewater was carried out using statistical experimental design methodology to evaluate the effects of three critical factors: slaked lime (calcium hydroxide, Ca(OH)(2)) concentration, iron chloride (FeCl(3)) concentration and wastewater volume. With these critical factors, the wastewater treatment process is modeled as an appropriate quadratic cost function of the turbidity of the clarified water. The model is optimized with Rosenbrock's method. Response surface topology of the wastewater treatment is given in terms of optimal concentrations of lime water and FeCl(3) and optimal wastewater volume at pH 11.     

Application of adaptive heuristic criticism control (AHCC) to dye wastewater

This paper presents an experimental application of AHCC to study the coagulation process of wastewater treatment in a dye plant. Also this study includes a series of tests in which an AHCC control was used for pH control. The performance results of the AHCC controller are compared with the results obtained by using a conventional proportional-integral-derivative (PID) algorithm. It is useful to compare PID with AHCC to illustrate the extreme range of the nonlinearity of the dye wastewater treatment process. Although the removal of pollutants from wastewater is similar with AHCC and PID, our results show excellent AHCC performance in the region where conventional PID control fails.     

南充炼厂循环水管理与处理技术探讨

文章介绍了南充炼油化工总厂循环水场循环水系统管理及处理技术现状,在与其他炼厂循环水处理状况分析比较的基础上,剖析了该厂循环水系统存在的问题,并就改善水系统、水冷设施和改进水处理技术、加大监测力度等方面进行了探讨,为炼油厂实现循环水全面达标、确保生产装置"安、稳、长、满、优"运行提供了参考。     

豆腐废水廉价培养制备微生物絮凝剂的研究

从活性污泥中筛选出一株有高效絮凝活性的菌株,经鉴定为酵母属(Saccharomyces sp).以豆腐废水为廉价培养基培养高效菌产生微生物絮凝剂,含有絮凝活性物质的发酵液的上清液对4g/L高岭土悬浊液的絮凝率达95.6%.正交实验表明,产生微生物絮凝剂的优化培养条件为:豆腐废水体积分数25%,初始pH值5.0,摇床速度160r/min,温度30℃.培养产生的微生物絮凝剂最佳收获时间为48 h.微生物絮凝剂在酸性和碱性环境中均有较好的适应性和热稳定性.     

Relationship between THC concentration in blood and impairment in apprehended drivers

OBJECTIVE: The most important psychoactive ingredient in cannabis, Delta (9)-tetrahydrocannabinol (THC) is one of the most frequently detected substances in blood samples from suspected impaired drivers in Norway. There is growing concern over possible links between the use of cannabis and increased risk of motor-vehicle crashes. Experimental studies have provided useful information on the role of THC and dose-effect relations with respect to psychomotor performance. The main purpose of the present study was to investigate whether a physician's judgment on impairment in a real-life setting among suspected drugged drivers, was related to blood THC concentration. METHODS: In Norway a police physician performs a clinical test for impairment (CTI) shortly after apprehension. The Norwegian Institute of Public Health analyze blood samples from all drivers suspected of driving under the influence of non-alcoholic drugs. In the present study 589 samples from approximately 30,000 cases of suspected drug impaired driving from the period 1997-99, contained THC as the only drug. In 456 of these cases a conclusion of the CTI was available. RESULTS: 230 (54%) drivers were considered not impaired and 226 (46%) impaired. Impaired drivers had higher blood THC concentration than the drivers who were judged as not impaired (median; 2.5 ng/mL (range; 0.3-45.3 ng/mL) vs 1.9 ng/mL (range; 0.32-24.8 ng/mL), (p < 0.05). Furthermore, drivers with blood THC concentrations above 3 ng/mL had an increased risk for being judged impaired compared to drivers with lower concentration ranges. CONCLUSION: The relationship between the concentration of THC in blood and risk of being assessed impaired found in this cross-sectional study of suspected drugged drivers, supports findings from previous experimental studies of concentration related effects of THC on psychomotor performance and driving skills.     

A practical look at the variable area transect

The variable area transect (VAT) is a plotless density estimator that has received little attention in the ecological literature despite having potentially robust estimation properties. VAT allows for density estimations without the lengthy search times associated with other plotless density estimators. In spite of this, little has been written about the effect of varying transect widths on its density estimation properties or on the practical implementation of the VAT in field settings. An artificial population sampler was used to examine the effect of transect width on density estimates obtained using the VAT. Three transect widths were chosen corresponding to the mean object size, the largest object size, and twice the size of the largest object. Transect width had a marked effect on the quality of the density estimation, with the largest transect width resulting in significant negative biases in estimation. For the narrowest width, most estimates were within 10% of the true value for a nonrandomly distributed population. The practical considerations of choosing a VAT transect width are enumerated.     

PCDD/Fs in ambient air collected in Zagreb, Croatia

Levels of PCDD/Fs were measured at four different sites in Zagreb, capital of Croatia. Also one sample was taken during spontaneously initiated open fire on a landfill and one sample where garden waste of unknown content was burnt. Over period 1997–2000, 28 samples were collected and levels ranged between 9 and 306 fg I-TEQ m⁻³, except in the sample collected during landfill fire. Air PCDD/F levels in Zagreb at four sites were different and the highest levels were observed in industrial area. Seasonal variation of levels is also evident with higher levels in winter than in summer. Our results show that PCDD/F levels in ambient air collected in Zagreb are at lower end of the published data range. In general, homologue profiles were quite similar for all locations, the concentration of PCDD homologues increased while the concentration of PCDF homologues decreased with increasing degree of chlorination. PCDD/F levels in the landfill fire sample was 13 200 fg I-TEQ m⁻³ which are much higher than levels in garden waste burning sample or in sample collected at industrial site. During landfill fire, the concentration of 2,3,7,8-TCDF becomes even higher than the concentration of OCDF and is equal to the concentration of 1,2,3,4,6,7,8-HpCDF.     

Bromate formation on the non-porous TiO2 photoanode in the photoelectrocatalytic system

The increasing use of ozone in water disinfection processes has been the focus of considerable concern in regards to inorganic disinfection by product formation of bromate in waters containing bromide. Due to the public health risk caused by the presence of bromate as a suspected carcinogen, attention had been addressed to the conditions under which bromate is formed. In this study, photoanodic bromine generation and bromate (BrO(3)(-)) formation were investigated using a TiO(2) electrode in a photoelectrocatalytic (PEC) treatment process. The separation of anodic and cathodic reactions in the PEC system resulted in a pH decrease from 9.3 to 3.0 in the photoanode compartment and an increase to 11.0 in the cathode compartment. Under a photo-illumination intensity of 5.7 m W cm(-2) UV, a biasing potential of +1.0V vs SCE, a pH of 6.0 and at a NaBr concentration of 1.0 x 10(-2) M, active bromine formation increased over time with 2.4 x 10(-6) M min(-6) rate and reached a steady-state concentration of 1.44 x 10(-4) M in 60 min. Bromate formation was detected after a lag-period of 15 min and exhibited a continuous increasing trend with respect to irradiation time. No bromate formation was observed below pH 6.5 whereas an increasing bromate concentrations and pH up to pH=8.5 were noted.