热分解技术在修复多氯联苯污染土壤中的应用

针对我国土壤中PCBs的污染特点,介绍了一种修复土壤的热分解技术,并详述了该技术的工作流程、影响因素、处理效率等问题。最后对该技术的发展趋势进行了展望,并对其在推广过程中可能遇到的困难进行了分析。     

Remediation of petroleum-contaminated soils by fluidized thermal desorption

A novel type of fluidized bed desorber was developed for the remediation of petroleum-contaminated soils at low temperature with high efficiency. Cahn balance® was utilized to investigate the thermal desorption behavior of soils contaminated by various hydrocarbons. The performance of the fluidized-bed desorber was investigated at different operating modes. Batch operation of the fluidized-bed desorber exhibited 99.9% desorption efficiency at temperatures of ca. 300°C within a half hour. Continuous operation of the fluidized-bed indicated that Q/F (the ratio of the mass flow rate of fluidizing gas to feeding rate of contaminated soils) is less important at higher temperature (>300°C), if proper fluidization is ensured. The periodic operation of the fluidized bed desorber shows the possibility to reduce off-gas volume significantly.     

Treatment of mercury‐contaminated soils with activated carbon: A laboratory,field, and modeling study

A series of laboratory batch leaching tests was conducted to evaluate the performance of different activated carbons in stabilizing mercury in soils. Based on the results of these experiments, an amendment application rate of 5 percent powdered activated carbon (PAC) was selected for in situ field application at a former industrial facility. A geochemical model was also developed to simulate the interactions between mercury and activated carbon in vadose‐zone soils. Modeling was used to (1) better understand possible mercury sequestration mechanisms and (2) predict the in situ performance of PAC. Model results indicate dissolved mercury concentrations observed in batch tests are consistent with equilibrium partitioning of mercury between dissolved organic matter, soil organic matter, and PAC. Activated carbon is predicted to reduce dissolved mercury concentrations via two mechanisms: (1) the formation of stable mercury complexes on PAC surfaces and (2) the direct adsorption of dissolved organic matter that would otherwise be available for mercury dissolution. Study results demonstrate PAC effectiveness for site soils with mercury concentrations below 200 mg/kg. © 2010 Wiley Periodicals, Inc.     

Characterizing soils contaminated with heavy metals: A uranium contamination case study

To stem rising remediation costs for soils contaminated with hazardous metals, increased emphasis is being placed on the development of in-situ and ex-situ treatment technologies. Often, a lack of basic information on the chemical and physical characteristics of the soil and contaminants hampers treatability studies used to design these technologies. This article proposes and demonstrates a characterization program to meet these information needs, employing standard analytical techniques coupled with advanced spectroscopy and microscopy techniques. To support treatments involving physical separation strategies, the program uses standard analytical techniques to characterize the soil and the association of contaminants with different soil fractions (e.g., size and density fractions). Where chemical treatments are required, spectroscopy and microscopy methods are employed to yield quantitative information on the oxidation state and speciation of the contaminant. Examples demonstrate the use of measured soil and contaminant characteristics in the screening of alternative treatment technologies and in the selection of soils for use in treatability studies. Also demonstrated is the use of these characterization tools in the design and optimization of treatment strategies and in support of risk assessment determinations.     

A laboratory study on migration of K+ in a two-layer landfill liner system.

Contaminant transport through the clay liner and the underIying secondary leachate drain layer (SLDL) in landfills was studied through a laboratory test, and analysis method on the transport of K+ in a two-layer soil system. The soils used for this study were Ariake clay and the underlying layer, Shirasu soil from the Kyushu region of Japan, representing the clay liner material and SLDL material, respectively. The effective diffusion coefficients (De) of the selected target chemical species, potassium (K+) for the Ariake clay and Shirasu soil were back-calculated using a computer program, and it was found that values of De derived from this study were consistent with those previously published. The hypothesis that the mechanical dispersion process can be negligible has been proved to be reasonable based on both the observation that the predicted values fit the experimental data and the analyses of two dimensionless parameters. Parametric analysis showed the transport of K+ through the soils is controlled by advection-diffusion rather than diffusion only, whereas at low Darcy velocity (i.e. < or = 10(-9) m s(-1)), transport of K+ would be controlled by diffusion. The test results and parametric analysis may be applied in design of landfill liners and SLDLs, particularly in coastal areas.     

中国与世界银行对新建火电厂的环保要求对比分析

详细介绍了中国和世界银行对新建火电厂的不同环保要求,比较分析了电厂污染物排放中的大气（颗粒物、二氧化硫、氮氧化物）、工业废水和噪声的排放限值,对规划、新建火电厂的主要污染物控制具有参考意义。     

Electroremediation: A study of the influence of buffering behavior in contaminated soils

This article presents the results of an experimental study conducted to evaluate the behavior of two types of andisol soils found in Tenerife, Canary Islands, Spain. The soils were evaluated in relation to their buffering capacity when confronted with acid and alkaline fronts generated during electroremediation treatment. The study was conducted using a cell, which established a continuous flow of distilled water through electrode chambers to remove H⁺ and OH^? generated during electrolysis. The results indicate that the soils had sufficient buffer capacity to support variations in pH independent of the maintenance of flow of solution in the electrode chambers. Although the mechanism of migration was not affected, the flow of water favored the movement of ions by diffusion monitoring of the electrolytic current allowed for a real‐time parameter to act as an indicator of the quantity of ions available in regions near the electrodes. © 2004 Wiley Periodicals, Inc.     

半饱和褐煤活性焦预吸附—生物降解—褐煤活性焦吸附组合工艺处理稠油废水的中试研究

为解决稠油废水的达标排放问题,构建了半饱和褐煤活性焦(HSLAC)预吸附—生物降解—褐煤活性焦吸附组合工艺处理稠油废水的中试装置(5 m3/h)。稠油废水经已吸附生化出水的HSLAC吸附预处理后,生物降解出水COD均值大幅降至82.49 mg/L,总出水COD均值为39.22 mg/L,实现了出水达标(COD≤50 mg/L)。三维荧光光谱分析表明,经HSLAC吸附预处理后,生化出水中溶解性有机碳浓度较未经吸附预处理时大幅降低,石油类和腐殖质是生化难降解的有机物。HSLAC预吸附可大幅降低处理成本。     

A dynamic study of the sorption and the transport processes of cadmium in calcareous sandy soils

The interactions of Cd2+ with silica and calcite were observed through laboratory dynamic experiments. Cd2+ sorption processes were characterised as a function of reaction kinetics in aqueous solutions saturated or not with respect to calcite. Chromatographic column experiments show that Cd2+ sorption on silica can be considered as a reversible equilibrate reaction which depends on water composition and pH. For a porous medium composed by a mixture of silica and calcite, the Cd2+ migration behaviours are predominantly controlled by calcite. The amount and the reversibility of sorbed Cd on calcite are strongly affected by kinetic limitations. Stirred flow through reactor experiments provide an original method to separate and characterise the 'fast' and 'slow' Cd sorption on calcite processes. The 'fast' Cd reversible adsorption isotherms and the rate of Cd subsequent uptake by 'slow' reactions are determined. In addition, the inhibition of calcite dissolution is observed as a function of sorbed Cd in order to provide a complete mechanistic database for coupled transport-geochemistry models.     

Comparison of end-of-life tire treatment technologies: A Chinese case study

The aim of this paper is to compare different end-of-life tire (ELT) treatment technologies in China from an environmental and economic perspective. Four treatment technologies were evaluated: ambient grinding, devulcanization, pyrolysis and illegal tire oil extraction.Life cycle assessment (LCA) was applied to evaluate the potential environmental impact of each treatment based on the Eco-indicator 99 (Hierarchist approach) method provided by GaBi 4 software. The final result shows that pyrolysis represents the environmentally benign option while illegal tire oil extraction caused the worst damages. For the three legal treatments, although high credit was obtained when considering avoided impacts from recycled materials and energy, they have great impact as to respiratory effects (inorganic) dominantly contributed by energy production stage, which implies that the emphasis on environmental policies related to ELT treatment should shift from the control of emissions from treatment process to the reduction of energy consumption.A simplified comparison of net benefits and total impacts shows that the most eco-effective ELT treatment technology is pyrolysis, followed by dynamic devulcanization and ambient grinding. The illegal tire oil extraction, however, must be prohibited immediately because of its highest environmental pollution and lowest net benefit.     

Cogeneration from thermal treatment of selected municipal solid wastes. A stoichiometric model building for the case study on Palermo

This paper aims to calculate the energetic and environmental effects of an integrated solid waste management system in Palermo, Italy. In particular, the thermal treatment of Municipal Solid Waste (MSW) with energy recovery is assessed. The current characterization at the local scale is taken into account. Two different options of collection are taken into account: (1) unselected wastes; and (2) sorted collection, according to the current Italian regulation. Combustion process is analyzed and the following features are calculated: (1) stoichiometric content of air and air excess; and (2) temperature and enthalpy of flue gases. Energy recovery is performed in the hypothesis of Hirn cycle both with steam condensation to produce only power, and with bleeding cycle for the combined production of power and thermal energy. Total electric efficiency is assumed as representative index of the technological level of the assessed plant. Results show that the thermal treatment of selected MSW, associated with a cogenerative recovery of energy, represents a relevant sustainable strategy of waste valorization as an alternative to fossil fuels.     

Feedstock recycling of waste polymers by thermal cracking in molten metal: thermodynamic analysis

Waste plastics contribute to serious environmental and social problems, such as the loss of natural resources, environmental pollution, and depletion of landfill space, but they also create demands on the environmentally-oriented part of the society. Feedstock recycling of scrap polymers by thermal and chemical methods is well known and environmentally accepted. The paper presents the results of thermodynamic analysis of the conversion of polyolefins in a fuel-like mixture of hydrocarbons using thermal cracking in a new type of tubular reactor with molten metal. Evaluation of the efficiency of the process was based on exergy calculations. Calculated exergy efficiency was ca. 79.5 %. It means that feedstock recycling of waste is better from an energetic and environmental point of view than other processes, particularly incineration.     

Feasibility study for thermal treatment of solid tire wastes in Bangladesh by using pyrolysis technology

In this study on the basis of lab data and available resources in Bangladesh, feasibility study has been carried out for pyrolysis process converting solid tire wastes into pyrolysis oils, solid char and gases. The process considered for detailed analysis was fixed-bed fire-tube heating pyrolysis reactor system. The comparative techno-economic assessment was carried out in US$ for three different sizes plants: medium commercial scale (144 tons/day), small commercial scale (36 tons/day), pilot scale (3.6 tons/day). The assessment showed that medium commercial scale plant was economically feasible, with the lowest unit production cost than small commercial and pilot scale plants for the production of crude pyrolysis oil that could be used as boiler fuel oil and for the production of upgraded liquid-products.     

A multi-criteria assessment of scenarios on thermal processing of infectious hospital wastes: A case study for Central Macedonia

In Greece more than 14,000 tonnes of infectious hospital waste are produced yearly; a significant part of it is still mismanaged. Only one off-site licensed incineration facility for hospital wastes is in operation, with the remaining of the market covered by various hydroclave and autoclave units, whereas numerous problems are still generally encountered regarding waste segregation, collection, transportation and management, as well as often excessive entailed costs. Everyday practices still include dumping the majority of solid hospital waste into household disposal sites and landfills after sterilization, still largely without any preceding recycling and separation steps. Discussed in the present paper are the implemented and future treatment practices of infectious hospital wastes in Central Macedonia; produced quantities are reviewed, actual treatment costs are addressed critically, whereas the overall situation in Greece is discussed. Moreover, thermal treatment processes that could be applied for the treatment of infectious hospital wastes in the region are assessed via the multi-criteria decision method Analytic Hierarchy Process. Furthermore, a sensitivity analysis was performed and the analysis demonstrated that a centralized autoclave or hydroclave plant near Thessaloniki is the best performing option, depending however on the selection and weighing of criteria of the multi-criteria process. Moreover the study found that a common treatment option for the treatment of all infectious hospital wastes produced in the Region of Central Macedonia, could offer cost and environmental benefits. In general the multi-criteria decision method, as well as the conclusions and remarks of this study can be used as a basis for future planning and anticipation of the needs for investments in the area of medical waste management.     

Co-processing of DVDs and CDs with vegetable cooking oil by thermal degradation

Waste DVDs and CDs were thermally degraded at 450°C by a semibatch process. In total, 40–50 wt% was converted into liquid product that consisted of phenol derivatives (∼75 wt%), bisphenol (∼10 wt%) and its derivatives, and small amounts of aromatic hydrocarbons such as benzene, toluene, ethylbenzene, dimethylbenzene, methylethylbenzene, diethylbenzene, and methylisopropyl benzene. Degradation of the polycarbonate support from DVDs and CDs was enhanced by coprocessing with vegetable cooking oil, the degradation of which gave a homologue series of hydrocarbons and organic acids with up to 25 and 18 atoms of carbon, respectively. Silver from the reflective coating on DVDs and CDs remained in the solid residue, its concentration increasing about 2.5 times compared to that of the original disks.     

Characterization of dried sewage sludge for co-firing in coal power plant by using thermal gravimetric analysis

This research studied the characteristics of dried sewage sludge using TGA to co-fire dried sewage sludge with coal in power plants. The sewage sludges that were discharged from Daejeon, Korea were dried and examined fundamental properties to use them as a fuel. Also, the properties of bituminous coal and wood pellet, which are used in domestic coal power plants, were analyzed and compared with them of sewage sludges and non-isothermal analyses of dried sewage sludges were performed at the heating rates of 5, 10, 20, and 30C /min using TG analyzer to investigate the basic combustion characteristics. As a results of these TGA/DTG analyses, sewage sludges showed its primary peak at the temperature of 250–500?°C, which overlapped with main peak of wood and secondary peak at around 500–600?°C, which overlapped with main peak of coals. Also for the interpretation by Friedman method, the activation energies in the section of highest weight loss were 525.16 kJ/mole for dried digested sewage sludge, 544.88 kJ/mole for dried excess sewage sludge, 203.86 kJ/mole for wood pellet and 146.4585 kJ/mole for bituminous coal. The reaction orders for dried digested excess sewage sludge, dried excess sewage sludge, wood pellet and bituminous coal were 28.775, 24.319, 18.398 and 9.1005, respectively, and the frequency factors were 5.89?\(\times \hspace{0.17em}\)10²⁸, 1.65?\(\times \hspace{0.17em}\)10^24,, 9.59?\(\times \hspace{0.17em}\)10¹⁶ and 1.77?\(\times \hspace{0.17em}\)10⁸ for each, respectively.     

Online elemental analysis of process gases with ICP-OES: A case study on waste wood combustion

A mobile sampling and measurement system for the analysis of gaseous and liquid samples in the field was developed. An inductively coupled plasma optical emission spectrometer (ICP-OES), which is built into a van, was used as detector. The analytical system was calibrated with liquid and/or gaseous standards. It was shown that identical mass flows of either gaseous or liquid standards resulted in identical ICP-OES signal intensities. In a field measurement campaign trace and minor elements in the raw flue gas of a waste wood combustor were monitored. Sampling was performed with a highly transport efficient liquid quench system, which allowed to observe temporal variations in the elemental process gas composition. After a change in feedstock an immediate change of the element concentrations in the flue gas was detected. A comparison of the average element concentrations during the combustion of the two feedstocks showed a high reproducibility for matrix elements that are expected to be present in similar concentrations. On the other hand elements that showed strong differences in their concentration in the feedstock were also represented by a higher concentration in the flue gas. Following the temporal variations of different elements revealed strong correlations between a number of elements, such as chlorine with sodium, potassium and zinc, as well as arsenic with lead, and calcium with strontium.     

Comparison of compostable bags and aerated bins with conventional storage systems to collect the organic fraction of municipal solid waste from homes. A Catalonia case study

The separation of biowaste at home is key to improving, facilitating and reducing the operational costs of the treatment of organic municipal waste. The conventional method of collecting such waste and separating it at home is usually done by using a sealed bin with a plastic bag. The use of modern compostable bags is starting to be implemented in some European countries. These compostable bags are made of biodegradable polymers, often from renewable sources. In addition to compostable bags, a new model of bin is also promoted that has a perforated surface that, together with the compostable bag, makes the so-called “aerated system”. In this study, different combinations of home collection systems have been systematically studied in the laboratory and at home. The results obtained quantitatively demonstrate that the aerated bin and compostable bag system combination is effective at improving the collection of biowaste without significant gaseous emissions and preparing the organic waste for further composting as concluded from the respiration indices. In terms of weight loss, temperature, gas emissions, respiration index and organic matter reduction, the best results were achieved with the aerated system. At the same time, a qualitative study of bin and bag combinations was carried in 100 homes in which more than 80% of the families participating preferred the aerated system.     

建设项目环境影响经济损益分析研究

介绍了建设项目环境影响经济损益分析的基本概念和主要内容，阐述了这一方法的应用原则并进行了利弊分析。针对我国开展建设项目环境影响经济损益分析中的一些突出问题提出了改进建议。     

A study of treatment options to remediate explosives and perchlorate in soils and groundwater at Camp Edwards,Massachusetts

The Army National Guard initiated an Innovative Technology Evaluation (ITE) Program in March 2000 to study potential remedial technologies for the cleanup of explosives‐contaminated soil and groundwater at the Camp Edwards site on the Massachusetts Military Reservation. The soil technologies chosen for the ITE program were: soil washing, chemical oxidation, chemical reduction, thermal desorption/destruction (LTTD), bioslurry, composting, and solid phase bioremediation. The technologies were evaluated based on their ability to treat both washed and untreated soil. A major factor considered was the ability to degrade explosives, such as RDX, found in particulate form in the soils. The heterogeneous nature of explosives in soils dictates that the preferred technology must be able to treat explosives in all forms, including the particulate form. Groundwater remediation technologies considered include: in situ cometabolic reduction, two forms of in situ chemical oxidation, Fenton‐like oxidation and potassium permanganate. This article presents the results of each of the remedial technologies evaluated and discusses which technologies met the established ITE performance goals. © 2003 Wiley Periodicals, Inc.