石屏异龙湖区域环境与经济开发规划研究

通过对异龙湖区环境与经济发展现状的诊断分析，把经济再生产的投入、产出与污染物的产生、排放及治理间的数量关系列表扩张而成模型、对湖区域环境与经济的投入产出进行分析，确定了包括水量调蓄、水污染治理、合理利用、强化管理等措施的综合治理途径，据此制订了湖区综合治理规划，提出了主要经济开发建设项目，并已在６个方面得到了应用。     

Kinetics of catalytic oxidation of benzene, n-hexane, and emission gas from a refinery oil/water separator over a chromium oxide catalyst

With the advances made in the past decade, catalytic incineration of volatile organic compounds (VOCs) has become the technology of choice in a wide range of pollution abatement strategies. In this study, a test was undertaken for the catalytic incineration, over a chromium oxide (Cr2O3) catalyst, of n-hexane, benzene, and an emission air/vapor mixture collected from an oil/water separator of a refinery. Reactions were carried out by controlling the feed stream to constant VOC concentrations and temperatures, in the ranges of 1300-14,700 mg/m3 and 240-400 degrees C, respectively. The destruction efficiency for each of the three VOCs as a function of influent gas temperature and empty bed gas residence time was obtained. Results indicate that n-hexane and the oil vapor with a composition of straight- and branch-chain aliphatic hydrocarbons exhibited similar catalytic incineration effects, while benzene required a higher incineration temperature or longer gas retention time to achieve comparable results. In the range of the VOC concentrations studied, at a given gas residence time, increasing the operating temperature of the catalyst bed increased the destruction efficiency. However, the much higher temperatures required for a destruction efficiency of over 99% may be not cost-effective and are not suggested. A first-order kinetics with respect to VOC concentration and an Arrhenius temperature dependence of the kinetic constant appeared to be an adequate representation for the catalytic oxidation of these volatile organics. Activation energy and kinetic constants were estimated for each of the VOCs. Low-temperature destruction of the target volatile organics could be achieved by using the Cr2O3 catalyst.     

城镇污水处理厂除磷影响因素及优化运行研究

随着全国重点流域城镇污水处理厂迎来新一轮提标改造,其中部分污水处理厂对出水总磷（TP）的排放限值由0.5 mg/L降低为0.3 mg/L,甚至降至0.2 mg/L,这对城镇污水处理厂除磷提出了新的挑战。通过对全国58座执行GB 18918-2002《城镇污水处理厂污染物排放标准》一级A标准的城镇污水处理厂进行调研分析,探讨了目前污水处理厂在实际生产运行中除磷存在的主要问题并给出相应对策,为今后高TP标准排放下污水处理厂的运行管理提供技术指导。调研结果表明:各污水处理厂的释磷潜力为0.01~23.98 mg/（g·h）,其平均值为2.77 mg/（g·h）,释磷潜力普遍较弱。生物除磷效果较差的主要原因为进水碳源不足、厌氧区存在高浓度硝态氮及同步化学除磷的抑制作用。基于上述调查分析,有针对性地提出了具体的调控措施,并建议污水处理厂要根据进水水质情况,通过静态实验确定最佳除磷药剂种类及合适的投加量,有效控制化学除磷过程,从而达到节省药耗的目的。     

Determination of Source Contributions to Ambient PM2.5 in Kaohsiung,Taiwan, Using a Receptor Model

ABSTRACT

Ambient particulates of PM_2.5 were sampled at three sites in Kaohsiung, Taiwan, during February and March 1999. In addition, resuspended PM_2.5 collected from traffic tunnels, paved roads, fly ash of a municipal solid waste (MSW) incinerator, and seawater was obtained. All the samples were analyzed for twenty constituents, including water-soluble ions, organic carbon (OC), elemental carbon (EC), and metallic elements. In conjunction with local source profiles and the source profiles in the model library SPECIATE EPA, the receptor model based on chemical mass balance (CMB) was then applied to determine the source contributions to ambient PM_2.5.

The mean concentration of ambient PM_2.5 was 42.6953.68 μj.g/m³ for the sampling period. The abundant species in ambient PM_2.5 in the mass fraction for three sites were OC (12.7-14.2%), SO₄ ^2- (12.8-15.1%), NO₃ ^- (8.110.3%), NH₄+ (6.7-7.5%), and EC (5.3-8.5%). Results of CMB modeling show that major pollution sources for ambient PM_2.5 are traffic exhaust (18-54%), secondary aerosols (30-41% from SO₄ ^2- and NO₃ ^-), and outdoor burning of agriculture wastes (13-17%).     

Kinetics of Catalytic Oxidation of Benzene,n-Hexane,and Emission Gas from a Refinery Oil/Water Separator over a Chromium Oxide Catalyst

ABSTRACT

With the advances made in the past decade, catalytic incineration of volatile organic compounds (VOCs) has become the technology of choice in a wide range of pollution abatement strategies. In this study, a test was undertaken for the catalytic incineration, over a chromium oxide (Cr₂O₃) catalyst, of n-hexane, benzene, and an emission air/vapor mixture collected from an oil/water separator of a refinery. Reactions were carried out by controlling the feed stream to constant VOC concentrations and temperatures, in the ranges of 1300–14,700 mg/m³ and 240–400 ° C, respectively. The destruction efficiency for each of the three VOCs as a function of influent gas temperature and empty bed gas residence time was obtained.

Results indicate that n-hexane and the oil vapor with a composition of straight- and branch-chain aliphatic hydrocarbons exhibited similar catalytic incineration effects, while benzene required a higher incineration temperature or longer gas retention time to achieve comparable results.

In the range of the VOC concentrations studied, at a given gas residence time, increasing the operating temperature of the catalyst bed increased the destruction efficiency. However, the much higher temperatures required for a destruction efficiency of over 99% may be not cost-effective and are not suggested. A first-order kinetics with respect to VOC concentration and an Arrhenius temperature dependence of the kinetic constant appeared to be an adequate representation for the catalytic oxidation of these volatile organics. Activation energy and kinetic constants were estimated for each of the VOCs. Low-temperature destruction of the target volatile organics could be achieved by using the Cr₂O₃ catalyst.     

Assessing the potential exposure risk and control for airborne titanium dioxide and carbon black nanoparticles in the workplace

Purpose  

This study assessed the potential exposure risks for workers in the workplace exposed to airborne titanium dioxide nanoparticles (TiO₂-NPs) and carbon black nanoparticles (CB-NPs). The risk management control strategies were also developed for the NP engineering workplace.     

采用重选法处理蚀刻废液零排放资源化新工艺

阐述了广州市白云区南溪化工厂开发出的一套国内首创的对线路板蚀刻废液进行大规模集中资源化处理的零排放处理新工艺,这套新工艺采用重力分选的方法将在固相条件下生成的氧化铜分离出来,克服了原有工艺的缺陷,达到了理想的分离效果,使废液中所有的成分能够在较低的处理成本下全部分离回收,完全无三废排出,达到了清洁生产的要求。     

Optimization for solidification of low-level-radioactive resin using Taguchi analysis

Solidification of low-level-radioactive (LLW) resin was optimized using Taguchi analytical methodology. The ingredients in LLW mortar which caused the solidification of cement were evaluated through consecutive measurements of the effects of various concentrations of ingredients. Samples selected according to Taguchi's method were separated into 18 different categories and measured at the 7th, 21st, and 28th day after fabrication on developing effects. Evaluations of the various samples focused on whether the compressive and bending strength fulfilled the special criteria of the Taiwan Power Company (TPC). Similar results indicated that both furnace slag and fly ash were the dominant material resulting from the solidification of LLW mortar. The superior combination was obtained as furnace slag 24 wt.%, fly ash 24 wt.%, and cement 8 wt.% to mix 24 wt.% of resin with 20 wt.% of water, to fulfill the contemporary requirements of TPC.     

Study On the Hydraulic Characteristics of Taichung Harbour in Taiwan

For this study, field measurements of current profiles, buoy trajectories and the lag of two tidal stations were performed to explore the flow characteristics of Taichung Harbour. in order to distinguish the effects of wind drift current on circulation inside Taichung Harbour, field surveys during both summer and monsoon (winter) season were completed separately. the speed of the drift current was about 3.5% that of the, wind speed, based on the field data. the horizontal dispersion coefficients were close to Bowden's (1965) formula for the tidal current. the water temperature showed a two-layer profile, with the mixing thickness about 4 to 6 metres for the upper layer. the corresponding Richardson number was about 70. the tidal lag between the two tidal stations was 9.68 minutes. All the results agree well with the theoretical results.     

Estimating the change of porosity in the saturated zone during air sparging

Introduction A ir sparging rem oves volatile organic conta- m inants from a saturated zone by com bining volatilization and aerobic biodegradation. A ir is injected below the w ater table through a slotted screen in a sparging w ell, and then rises to the…