太湖内源释放及营养盐输运研究

从对流-扩散方程出发,通过公式推导,建立了包含底泥污染的水流-水质模型,对模型进行了率定和验证后,应用于太湖.该模型将湖泊水相和内源悬移相污染作为一个整体,结合污染物在悬移泥沙上的各种迁移过程,研究了太湖总氮、总磷内源释放的分布和数量,过程中考虑了悬移泥沙的各种影响因素,得到了较理想的模拟结果,当风速≤3.5 m/s时,冲刷和悬移造成的内源污染物释放量较小,内源污染物释放主要通过泥-水界面的静态释放;当风速>3.5 m/s时,冲刷和悬移造成的内源污染物释放量随风速增加迅速增大.通过计算得出2001年太湖内源释放的总氮为3.0万t,总磷为0.8万t.     

生物滴滤塔净化苯乙烯废气的实验研究

采用生物滴滤(BTF)系统对含苯乙烯的有机废气进行了生物净化实验并研究该系统VOCs生物降解性能。实验表明,苯乙烯进气浓度低于20 mg/m3时BTF去除效率可达92%以上,出口苯乙烯浓度低于1.6 mg/m3,达到GB14554-1993中规定的排放标准;该BTF装置对苯乙烯的去除负荷在2.0 g/(m3.h)左右;系统稳定运行时循环液COD、浊度和pH等都保持稳定,无脱落生物膜积累现象;生物滴滤塔系统适宜的气液比为300;系统总压降约100 Pa,鲍尔环填料和聚氨酯发泡填料混合装填方式可以降低系统压降并有利于微生物挂膜。     

沛沿河流域土壤肥料释放的降雨模拟研究

为有效控制农业面源污染,改善沛沿河流域水质状况,通过对水稻田、杨树林和果园的土壤分别施用不同类型化肥后,模拟研究了土壤在受雨水短期浸泡及连续降雨情况下氮、磷的释放特征。研究结果表明,稻田土壤对氮磷的保肥能力最佳,施肥时应以基肥为主;果园土壤及林地土壤的保肥能力均劣于稻田土壤,应采用少量多次追肥的方法。尿素与碳铵宜做基肥使用,而氯化铵与硫酸铵宜做追肥使用。     

Tributyltin distribution in the coastal environment of Peninsular Malaysia

The occurrence of tributyltin (TBT) is reported in the coastal waters of a few selected sites in Peninsular Malaysia. Water, bivalves and sediment samples collected were analysed specifically for TBT using sensitive analytical methods which involved a solvent extraction procedure with appropriate clean-up followed by graphite furnace atomic absorption spectrometric measurements. The levels of TBT in the seawater in unexposed areas were found in the range from <3.4 to 20 ng litre(-1) as compared to coastal areas with high boat and ship activities where TBT levels in seawater were generally above 30 ng litre(-1), with the highest level found at 281.8 ng litre(-1). TBT levels in the tissues of random cockle and soft-shell clam samples from local markets were found in the range from <0.5 to 3.7 ng g(-1) wet weight. The levels of TBT found in green mussel samples both from the market (23.5 ng g(-1) wet weight) and those from a mussel farm (14.2 ng g(-1) wet weight) indicate slight accumulation of TBT. In sediments, TBT levels were found ranging from <0.7 ng g(-1) dry weight in unexposed coastal sites to as high as 216.5 ng g(-1) dry weight for a site within a port area.     

高压纸上电泳研究汞的络合水解状态 ⅠHgCl2-NaCl体系

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The quality of fiber counts using improved slides with relocatable fields

A parameter based on discrepancies between reported fibers and verified fibers of relocatable slides is shown to be effective in monitoring the quality of airborne fiber counts. Analysts report only the fibers in each field examined. The verified fibers were determined by two experienced analysts, and are here considered as a "true" value. Most of the verified fibers were confirmed by the reported fibers, and the disputed fibers or fiber counting errors were all located and accounted for. In this study, reference (REF) slides were manufactured from proficiency analytical test (PAT) filter samples from the American Industrial Hygiene Association containing chrysotile or amosite. The slides were made using coverglasses bearing a grid pattern to allow accurate re-examinations. These coverglasses are an improved version of those used in previous studies. Seventy-four out of 85 amosite results and 51 out of 60 chrysotile results of REF slides were within their PAT proficiency ranges. When all reported fibers were normalized against their respective verified fibers, the average fiber count was over-estimated for amosite by 38.3% and under-estimated for chrysotile by 30.4%. The error from counting short fibers (sizing-extra) was 82.6% of the extra fibers and accounted for the 38% over-estimation of amosite fibers. For chrysotile fibers, sizing-extra errors were 74.0% of the extra fibers, but by far the larger errors were oversight-missing errors, which were 96.7% of the missing fibers and accounted for the 30% under-estimation of the chrysotile fibers. The discrepancies were found to be linearly related to counting errors as had been noted in a previous study, giving further weight to a proposed score, calculated from the discrepancy parameter (SigmaD(+) + |SigmaD(-)|)/VF(total), for evaluating the proficiencies of analysts. If a proficiency score =60 is selected, 48 out of 85 amosite results and 17 out of 60 chrysotile results satisfied this criterion in this study. The number of fiber counting errors in this study was larger than could be expected by PAT proficiency criteria. It may be useful to complement existing proficiency test programs with these REF slides. At the end of each proficiency testing round, detailed reports of discrepancies can be provided to participants so that they can improve on their skills in searching and sizing fibers and minimize their counting errors. In addition, the internal quality control program of each laboratory could include counting REF slides regularly by all analysts with control charts of (SigmaD(+)/VF(total)), (SigmaD(-)/VF(total)), (SigmaD(+) + |SigmaD(-)|)/VF(total) and RF(total)/VF(total) maintained to monitor errors, proficiencies and intercounter variations. Ten percent of relocatable slides of routine samples could also be recounted to monitor intracounter variation.     

Use of tandem circulation wells to measure hydraulic conductivity without groundwater extraction

Conventional methods to measure the hydraulic conductivity of an aquifer on a relatively large scale (10-100 m) require extraction of significant quantities of groundwater. This can be expensive, and otherwise problematic, when investigating a contaminated aquifer. In this study, innovative approaches that make use of tandem circulation wells to measure hydraulic conductivity are proposed. These approaches measure conductivity on a relatively large scale, but do not require extraction of groundwater. Two basic approaches for using circulation wells to measure hydraulic conductivity are presented; one approach is based upon the dipole-flow test method, while the other approach relies on a tracer test to measure the flow of water between two recirculating wells. The approaches are tested in a relatively homogeneous and isotropic artificial aquifer, where the conductivities measured by both approaches are compared to each other and to the previously measured hydraulic conductivity of the aquifer. It was shown that both approaches have the potential to accurately measure horizontal and vertical hydraulic conductivity for a relatively large subsurface volume without the need to pump groundwater to the surface. Future work is recommended to evaluate the ability of these tandem circulation wells to accurately measure hydraulic conductivity when anisotropy and heterogeneity are greater than in the artificial aquifer used for these studies.     

医院污水处理设备管理

提高废水处理设备运转率,完好率的首先问题是废水处理设备归谁管、怎样管的问题,纳入企业管理的组成部分,明确管理部门,建立以设备选型到报废更新的工作程序,制定管理制度和岗位责任制,分清职责,分工协作,齐抓共管.同时,因为废水处理设备有它的运行、操作、保养、维修规律,正确操作与维修保养才能使设备处于良好的技术状态,同时机械设备在长期运行中,因摩擦、高温、湿气和各种化学效应的作用不可避免地遣成零部件损坏,配合失调,技术状态逐渐恶化,作业效果逐渐下降.多年实践证明作好废水处理管理的五个要点,才能及时、快速、高质量地维修设备以恢复性能,处于良好的工作状态.