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281.
采用静态吸附实验,对比了岷江砂、沱江砂、青衣江砂、沸石、活性炭对猪场废水厌氧消化液中氨氮的吸附去除效率,基于氨氮去除能力、购买成本与运费的比较,筛选出性价比较高的基质--岷江砂作为四川地区人工湿地的基质处理猪场废水厌氧消化液.吸附实验表明,砂对氨氮的去除率随振荡时间和投加量的增加而增加.通过吸附等温曲线Langmuir...  相似文献   
282.
Pollution prevention/waste minimization is a win-win-win situation for government, industry, and the public, which offers more than just protection of the environment for all. Industry gains from reduced capital and operating costs, reduced liabilities, cleaner and safer working conditions, conservation of energy and material resources, and the opportunity for government and industry to work together in a cooperative manner. However, a number of regulatory barriers exist which discourage pollution prevention/waste minimization. This paper provides examples from the aluminum, chemical, petroleum, and wood treating industries of how these regulatory barriers become disincentives. To promote pollution prevention/waste minimization, Congress and the U.S. EPA need to reexamine those RCRA provisions which support a command and control strategy that creates the barriers. The barriers include the distinction between value and valueless materials, offsite storage requirements prior to reuse/recycle, the “Derived from Rule”, the “Burning for Fuel Rule”, land ban technology standards, and RD&;D restrictions. A new RCRA Pollution Prevention/Waste Minimization subtitle is proposed to eliminate or minimize these barriers.  相似文献   
283.
Environmental Science and Pollution Research - Improved understanding of the fractionation and geochemical characteristic of rare earth elements (REEs) from steel plant emissions is important due...  相似文献   
284.
碳羟基磷灰石对水中Cr(Ⅵ)的吸附性能研究   总被引:2,自引:0,他引:2  
利用废弃蛋壳为原材料,水热法合成碳羟基磷灰石(CHAP),并利用X射线衍射、扫描电镜、能谱分析手段对其结构进行了表征.将CHAP作为含铬废水的吸附剂,考察了pH、Cr(Ⅵ)初始浓度、吸附时间等对Cr(Ⅵ)吸附行为的影响.结果表明,初始质量浓度为50 mg/L的Cr(Ⅵ)溶液,在常温(22±2) ℃、溶液pH为3.0、CHAP用量为5 g/L时,30 min基本达到吸附平衡,Cr(Ⅵ)去除率为98.3%,饱和吸附容量达29.85 mg/g.CHAP对Cr(Ⅵ)的吸附行为符合Langmuir吸附等温式和Freundlich吸附等温式,相关系数分别为0.998 4和0.922 6.通过10%(体积分数)H2SO4对吸附Cr(Ⅵ)的CHAP进行再生,再生率最高达95.8%.  相似文献   
285.
针对北京城市河湖的污染状况,论述了传统絮凝-气浮工艺在污染治理中的应用研究及以该工艺为基础的集成系统的开发.结果表明,该系统对TP、COD去除率分别达81%和75%.该系统的研制成功为城市河湖的污染治理开辟了新途径.  相似文献   
286.
287.
张衍  郑炜  刘锐  李伟  李荧  陈吕军 《环境工程学报》2012,6(12):4355-4360
对化学合成橡胶碱洗废水进行了有机组分和可生化性分析,废水主要含有氯甲烷、六甲苯、异丁醇、甲醇等污染物质,生化降解实验中废水TOC可在6 d内从60.9 mg/L下降至0.0 mg/L,可生化降解性好,适于生化处理。选择混凝-生物接触氧化组合工艺对废水进行处理,采用优化条件(pH=8、PAC=40 mg/L、PAM=8 mg/L)进行混凝,碱洗废水COD去除率为9.95%~72.94%(平均31.51%);混凝后的碱洗废水与冲洗废水1∶5混合进行接触氧化处理,在HRT为36 h的情况下,COD去除率为65.6%~72.6%(平均70.4%),出水COD为134~331 mg/L,满足企业废水排放市政管网的要求;同时,实验发现COD去除率与COD容积负荷存在指数函数变化关系。  相似文献   
288.
    
ABSTRACT

A laboratory thermal desorption apparatus was used to measure emissions from a number of nominally identical photocopier toners—manufactured to meet the specifications of one specific model copier—when these toners were heated to fuser temperature (180-200 °C). The objective was to assess how potential volatile organic compound (VOC) emissions from the toner for a given copier can vary, depending upon the production run and the supplier. Tests were performed on a series of toner (and associated raw polymer feedstock) samples obtained directly from a toner manufacturer, representing two production runs using a nonvented extrusion process, and on toner cartridges purchased from two local retailers, representing three different production lots (histories unknown). The results showed that the retailer toners consistently had up to 350% higher emissions of some major compounds (expressed as |ig of compound emit-ted/g of toner), and up to 100% lower emissions of others, relative to the manufacturer toners (p ≤ 0.01). The manufacturer toners from one production run had emissions of certain compounds, and of total VOCs, that were modestly higher (13-18%) than those from the other run (p ≤ 0.01). The emission differences between the retailer and manufacturer toners are probably due to differences  相似文献   
289.
    

The present study aimed to improve the performance of microbial fuel cells (MFCs) by using an intermittent connection period without power output. Connecting two MFCs in parallel improved the voltage output of both MFCs until the voltage stabilized. Electric energy was accumulated in two MFCs containing heavy metal ions copper, zinc, and cadmium as electron acceptors by connection in parallel for several hours. The system was then switched to discharge mode with single MFCs with a 1000-Ω resistor connected between anode and cathode. This method successfully achieved highly efficient removal of heavy metal ions. Even when the anolyte was run in sequencing batch mode, the insufficient voltage and power needed to recover heavy metals from the cathode of MFCs can be complemented by the developed method. The average removal ratio of heavy metal ions in sequencing batch mode was 67 % after 10 h. When the discharge time was 20 h, the removal ratios of zinc, copper, and cadmium were 91.5, 86.7, and 83.57 %, respectively; the average removal ratio of these ions after 20 h was only 52.1 % for the control group. Therefore, the average removal efficiency of heavy metal ions increased by 1.75 times using the electrons stored from the bacteria under the open-circuit conditions in parallel mode. Electrochemical impedance data showed that the anode had lower solution resistance and polarization resistance in the parallel stage than as a single MFC, and capacitance increased with the length of time in parallel.

  相似文献   
290.
多氯联苯醚类化合物污染研究进展   总被引:2,自引:0,他引:2       下载免费PDF全文
综述了当前国际上多氯联苯醚的研究现状,详细论述了环境中多氯联苯醚的来源、毒性效应、污染状况、迁移转化和生物富集规律以及多氯联苯醚形成机制.我国关于多氯联苯醚类污染物的研究相对滞后,当前开展适合我国国情的多氯联苯醚物质的环境水平、生态安全与毒理学研究十分必要.  相似文献   
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