Assessing the Phytoremediation Potential of Tall Fescue and Sericea Lespedeza for Organic Contaminants in Soil

The phytoremediation potential of using tall fescue (Festuca arundinacea Schreb.) grass and sericea lespedeza (Lespedeza cuneata [Dum. ‐Cours.]) legume species was assessed using three different groups of organic contaminants in soil. One hundred parts per million (ppm) each of a nitroaromatic compound (TNT), a polycyclic aromatic hydrocarbon (Pyrene), and a polychlorinated biphenyl (Aroclor 1248) were used to contaminate the soils. The experiments were conducted using soils with high and low organic‐matter content. The results indicate that recoveries of Pyrene and TNT were very low in all treatments in soil with high organic‐matter content (6.3 percent) compared with recoveries in soil with low organic‐matter content (2.6 percent). In contrast, recoveries of PCB from soil were not dependent on the soil's organic‐matter content. Planting both the legume and grass species had significant effect on the transformations of TNT and PCB in the soil with low organic‐matter content and did not affect the fate of Pyrene in both soils. The amount of TNT transformed in the four months of plant growth was 63 percent in the tall fescue and 46 percent in the sericea‐planted soils, compared with only a 15 percent unaccounted loss in the unplanted control soils. Furthermore, the grass species, with its massive root system, was significantly better at causing TNT dissipation compared with the legume species, which has less root vegetative mass. The plant biomass, particularly the shoot weight of the tall fescue grass, was significantly increased as a result of TNT treatment. Tall fescue and sericea biomass did not appear to have any significant effect on Pyrene transformation. Planting sericea provided a significantly high level of PCB transformation in soils with either high or low amounts of organic matter. Tall fescue did not appear to have any significant effect on PCB transformation. © 2002 Wiley Periodicals, Inc.     

A Study of the Use of Alfalfa (Medicago sativa L.) for the Phytoremediation of Organic Contaminants in Soil

This article presents the results of a study that was conducted to determine the effectiveness of using alfalfa (Medicago sativa L.) to enhance the phytoremediation of three different types of chemical contaminants. The chemicals studied were trinitrotoluene (TNT), the polycyclic aromatic hydrocarbon (PAH) pyrene, and the polychlorinated biphenyl (PCB) Aroclor 1248. Experiments were conducted using soils that contained high and low organic matter content. The results indicated that recoveries of pyrene and TNT from soil were highly dependent on the soil organic matter content, while the recovery of PCB was not. Significantly low levels of pyrene and TNT were recovered from all treatments in the soil with 6.3 percent organic matter content compared to recovery levels found in soil with 2.6 percent organic matter. The presence of alfalfa plants had a significant effect on the transformation of TNT and PCB in the low organic matter content soil only and had no effect on the fate of pyrene. In the low organic matter soil, only 15 percent and 17 percent of the initial TNT and PCB levels, respectively, were transformed in the unplanted control soils compared to 66 percent and 77 percent in the alfalfa planted pots. In both soil types, pyrene dissipation could not be attributed to the presence of alfalfa plants. Overall, it was concluded that under high soil organic matter conditions, adsorption and covalent binding to the soil organic matter appeared to be the dominant force of pyrene and TNT removal. The effectiveness of using alfalfa to enhance PCB and TNT transformations was more significant in the lower organic matter soil; thus phytoremediation had a greater effect in soils with lower organic matter content. © 2001 John Wiley & Sons, Inc.     

Characterization of Sorghum Bran/Recycled Low Density Polyethylene for the Manufacturing of Polymer Composites

The objective of the study was to investigate the suitability of using sorghum bran in recycled low density polyethylene (R-LDPE) composites manufacturing. In response to the disposal of environmental problematic agricultural and polymer waste, composite sheets using recycled low density polyethylene and sorghum bran of different loadings (5, 10, 15 and 20 wt%) were prepared by melt compounding and compression molding. The effects of sorghum bran loadings on the mechanical, thermal, water absorption, swelling and crystalline properties of the composites were determined. Characterization of composites was carried out using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermo gravimetric (TGA/DTG) and mechanical analyses. It was found that increasing fiber loadings resulted to increased moduli and tensile strength while hardness was decreased. XRD indicated that fiber addition to R-LDPE did not change characteristic peak position. DSC results showed that the R-LDPE had significantly larger peak heat flow during cooling run than the blank R-LDPE, showing higher crystallization rates for R-LDPE. The results obtained confirmed that sorghum bran particles showed some potential as a good reinforcement in polymer matrix composites and indicate its thermal stability for possibly future composite applications.     

On the Methods for the Delimitation of Seasons

It is well known that air pollution is one of the major factors affecting human health and the activities in a town. Among the various air pollutants an interesting one, especially for sunny climates, is the reactive O₃. O₃ varies significantly through the year; it is therefore very important to know the onset and the duration of the warm period of the year since at that time O₃ concentrations increase significantly. In this work, an attempt was made to determine the onset of warm season of the year as well as its duration in various sites located in Northeastern Mediterranean. For this purpose, a fuzzy clustering method is used. The method was applied on the isobaric thickness between 1000 and 500 hPa for the period from 1974 to 1997. The results were compared to conventional methods based on synoptic classification and were found to be in good agreement.     

The Use of Hydrogen Release Compound for the Accelerated Bioremediation of Anaerobically Degradable Contaminants: The Advent of Time-Release Electron Donors

Hydrogen Release Compound (HRC®) is a simple, passive, low-cost, and long-term option for the anaerobic bioremediation of chlorinated hydrocarbons (CHs) via reductive dehalogenation. Applications to the remediation of other compounds, such as MTBE and perchlorate, that are anaerobically degradable by other reductive mechanisms, are in progress. HRC should be viewed as a tool for the acceleration of natural attenuation at sites that would otherwise require high levels of capital investment and operating expense. HRC is a proprietary, food-quality, polylactate ester that, upon being deposited into the subsurface, slowly degrades to lactic acid. Lactic acid is then metabolized to hydrogen, which in turn drives the reductive dechlorination of CHs. This has been demonstrated effectively in the laboratory and in the field. HRC can be manufactured as a moderately flowable, injectable material, or as a thicker, implantable hard gel, to facilitate localized treatment and passive barrier designs. HRC is best utilized for the remediation of dissolved phase plumes and the associated hydrophobically sorbed contaminant. The use of HRC is not appropriate for use on free-phase DNAPL unless the total mass to be remediated is within the scope of economic feasibility in comparison to alternative treatments. Evidence suggests there is competition between reductive dehalogenators and methanogens in which the methanogens compete for the use of hydrogen in the conversion of carbon dioxide to methane. Some researchers believe that a low concentration of hydrogen favors the reductive dehalogenators and starves out the methanogens. The objective, therefore, is to keep hydrogen concentrations low. The time-release feature of HRC, which is based on the hydrolysis rate of lactic acid from the ester and the subsequent lag time to hydrogen conversion, facilitates this objective. HRC, therefore, becomes a passive form of accelerated natural attenuation, in contrast to the more capital-and management-intensive alternatives now available. Laboratory and field results are presented, the latter expanding on the first uses of HRC by various members of the engineering and consulting firm community. © 1999 John Wiley & Sons, Inc.     

The Use of Oxygen Release Compound for the Accelerated Bioremediation of Aerobically Degradable Contaminants: The Advent of Time-Release Electron Acceptors

Oxygen Release Compound (ORC®) is a patented formulation of intercalated magnesium peroxide that releases oxygen slowly when hydrated. ORC treatment represents a “low intensity” approach to site remediation. It provides a simple, passive, low-cost and long-term acceleration of aerobic natural attenuation and has been shown to cost-effectively reduce time to site closure. ORC is now a proven technology as evidenced by its five years of use on over 5,000 sites in 50 states and 11 countries, and the existence of a full body of independent, peer reviewed literature on its performance. The first applications of ORC were for the treatment of benzene, toulene, ethylbenzene, and xylene (BTEX) and other light petroleum hydrocarbon fractions. Use has now expanded to the treatment of heavier fractions such as heating oil and some of the Polycyclic aromatic hydrocarbons (PAHs). More recently. ORC has been used to bioremediate the highly mobile and problematic gasoline oxygenate methyl tertiary butyl ether (MTBE) and has been applied to sites impacted with nitroaromatics, chloroaromatics, and some of the lower-order chlorinated hydrocarbons that can be treated aerobically—most notably vinyl chloride. Since ORC is an insoluble powder, it can be packaged in material composed of a specially designed filter fabric. These “filter socks” are then contacted with contaminated groundwater via an array of wells or trenches. ORC can also be mixed directly with water to form a slurry for permanent injection applications in the saturated zone or dispersed in powdered form for the in-situ or ex-situ treatment of soil. A broad array of treatment points, in which ORC slurry is backfilled or injected, can be implemented with low-cost, small-bore push-point technologies to directly treat dissolved phase plumes and moderate levels of sorbed contaminants. Powder or slurry is traditionally used in the remediation of residual contamination at the bottom of contaminated soil excavations. © 1999 John Wiley & Sons, Inc.     

Molecular Weight Changes and Polymeric Matrix Changes Correlated with the Formation of Degradation Products in Biodegraded Polyethylene

The molecular weight changes in abiotically and biotically degraded LDPE and LDPE modified with starch and/or prooxidant were compared with the formation of degradation products. The samples were thermooxidized for 6 days at 100°C to initiate degradation and then either inoculated with Arthobacter paraffineus or kept sterile. After 3.5 years homologous series of mono- and dicarboxylic acids and ketoacids were identified by GC-MS in abiotic samples, while complete disappearance of these acids was observed in biotic environments. The molecular weights of the biotically aged samples were slightly higher than the molecular weights of the corresponding abiotically aged samples, which is exemplified by the increase in from 5200 g/mol for a sterile sample with the highest amount of prooxidant to 6000 g/mol for the corresponding biodegraded sample. The higher molecular weight in the biotic environment is explained by the assimilation of carboxylic acids and low molecular weight polyethylene chains by microorganisms. Assimilation of the low molecular weight products is further confirmed by the absence of carboxylic acids in the biotic samples. Fewer carbonyls and more double bonds were seen by FTIR in the biodegraded samples, which is in agreement with the biodegradation mechanism of polyethylene.     

Methods for determining the biomass content of waste.

As CO2 emission trading in Europe has been established it is of essential importance to distinguish between biogenic and fossil emissions. Emissions resulting from bio-fuels and biogenous fractions are categorized as climate-neutral. Determination of plants using only fossil or bio-fuels is simple but categorization becomes more difficult for plants using a mix of fossil and bio-fuel such as solid recovered fuels. In the meantime, different methods for solving this problem have been developed. Using different approaches and technologies, all of these methods have the same goal: determining the biomass content (biogenic fraction), for example, in solid recovered fuels or in the off-gas of a mono- or co-incineration plant in order to calculate the biogenic carbon dioxide emissions. In the following article, the most common methods for determining the biogenic fraction of fuels, namely the Selective Dissolution Method, the Balance Method and the 14C-Method will be explained in detail.     

Immobilization of Horseradish Peroxidase on Macroporous Glycidyl-Based Copolymers with Different Surface Characteristics for the Removal of Phenol

Journal of Polymers and the Environment - Novel macroporous copolymers of glycidyl methacrylate and ethylene glycol dimethacrylate with mean pore size diameters ranging from 150 to...     

Assessment of the Whole Environmental Degradation of Oxo-Biodegradable Linear Low Density Polyethylene (LLDPE) Films Designed for Mulching Applications

The current paper is aimed at understanding the environmental fate of linear low density polyethylenes (LLDPE) films designed for mulching purposes and loaded with different pro-degradant additives. These were analyzed, upon exposure to natural sunlight for a period intended to mimick a general crop season in the mediterranean region. The selected samples underwent a relatively low extent of degradation as monitored by carbonyl index, molecular weight variation, extractability by solvent, changes in the onset of the decomposition temperature and crystallinity. The tendency to biodegradation of outdoor exposed LLDPE was then assessed under different environmental compartments including soil medium, aqueous medium as well as in axenic culture of white-rot fungus Phanerochaete chrysosporium. That fungus is known to be effective in the degradation of recalcitrant organic materials and plastic items. During the soil burial biodegradation test, lasted for 27?months, samples specimen were withdrawn at time intervals and characterized by means of structural and thermal analysis. These analytical assessments allowed to monitor any progress of oxidative degradation as a direct effect of the incubation in an active microbial environment. Analogous characterizations were carried out at the end of the biodegradation tests in aqueous medium and in P. chrysosporium axenic cultures. Data presented here are in keeping with the initial abiotic oxidation via a free radical chain reaction promoted by a pro-degradant additive acting on hydroperoxides and peroxide moieties present initially in the polymer bulk. This step was followed by a free radical cascade reactions leading to degradation once the oxidation started under relatively mild conditions (sunlight exposure). During the incubation step in soil, the abiotically degraded samples underwent significant variation in the level of oxidation and degradation with respect to the detected starting values. Indications were gained on the synergistic effect of a random fashion microbial metabolization coupled to biotically mediated oxidation of the original abiotically fragmented samples. Similar results were obtained in the biodegradation tests carried out in the aqueous media and in presence of P. chrysosporium axenic cultures. These evidences are suggesting the role of natural occurring microorganisms in promoting both partial oxiditation and degradation of LLDPE samples in combination with contextual mineralization process of the oxidized fragments.     

Assessment of Several Test Methods for the Determination of the Anaerobic Biodegradability of Polymers

Anaerobic degradation of eight commercially available biodegradable polymers was compared in two anaerobic tests using digestion sludge, according to ISO 11734 and ASTM D.5210-91. Cotton, polyhydroxybutyrate/hydroxyvalerate copolymer (PHB/PHV), starch blend, thermoplastic cellulose acetate, and cellulose acetate fibers proved to be anaerobically degradable, but only a low extent of degradation was found for polylactide, polyvinylalcohol, and polycaprolactone. Both test methods gave the same overall results, but with the ISO medium, longer lag phases and greater ranges of variation in the results were observed. These effects are presumably due to low concentrations of carbon dioxide in the ISO medium. Carbon dioxide has been demonstrated to be essential for the growth of various anaerobic bacteria, notably homoacetogenic and methanogenic bacteria.     

Potential Use of Recycled PET in Comparison with Liquid Crystalline Polyester as a Dual Functional Additive for Enhancing Heat Stability and Reinforcement for High Density Polyethylene Composite Fibers

The recycle poly(ethylene terephthalate) (rPET) used as an alternative reinforcing material for in situ microfibrillar-reinforced composite, compared with liquid crystalline polymer (LCP), was investigated. The PE-LCP and PE-rPET composites were prepared as fiber using hot drawing process. The effects of draw ratios and compatibilizer (styrene-ethylene butylene-styrene-grafted maleic anhydride, SEBS-g-MA) loading on morphology, tensile properties, thermal stability and dynamic mechanical characteristics of the LCP- and rPET-composite systems were studied. In as-spun samples containing compatibilizer, the fibrillation of LCP domains was observed whereas rPET domains appeared as droplets. After drawing, good fibrillation of LCP and rPET domains is remarkably observed especially in the composite fibers with compatibilizer loading. The mechanical properties of the composite fibers were strongly depended on the fibrillation of the dispersed phases which directly related the levels of draw ratio and compatibilizer loading. The mechanical properties enhanced by SEBS-g-MA were more pronounced in the rPET than LCP systems. The presence of rPET in the composite fibers alone or with the compatibilizer clearly improved the thermal resistance of PE whereas no significant change in thermal stability for the LCP-containing composite fibers with and without compatibilizer loading. The results from dynamic mechanical analysis revealed that an improvement in dynamic mechanical properties of the composite fibers could be achieved by drawing with optimum draw ratio together with optimum compatibilizer dosage. All obtained results suggested the high potential of rPET minor blend-component as a good reinforcing and thermal resistant materials for the thermoplastic composite fiber, in replacing the more expensive LCP.     

硫酸生产废水中砷去除方法的研究

对硫酸生产中水洗净化工序排放的废水分别采用灰灰石和鼓风氧化法,铁屑法和铁盐法进行处理试验,结果表明,采用铁盐法级处理工艺处理废废水是可行的,控制组处理的ＰＨ分别为８－１０和８－９,Ｆｅ／Ａｓ摩尔比分别为１和５,当进水Ａｓ含量为１１５ｍｇ／Ｌ时,经两组处理后,出水Ａｓ含量〈０．５ｍｇ／Ｌ,重金属离子,ＰＨ,ＳＳ等指标均符合国家排放标准。     

Classification and categorization of treatment methods for ash generated by municipal solid waste incineration: A case for the 2 greater metropolitan regions of greece

The primary goal of managing MSW incineration residues is to avoid any impact on human health or the environment. Incineration residues consist of bottom ash, which is generally considered as rather harmless and fly ash which usually contains compounds which are potentially harmful for public health. Small quantities of ash (both bottom and fly) are produced currently in Greece, mainly from the healthcare waste incineration facility in Attica region. Once incineration plants for MSW (currently under planning) are constructed in Greece, the produced ash quantities will increase highly. Thus, it is necessary to organize, already at this stage, a roadmap towards disposal/recovery methods of these ash quantities expected.Certain methods, related to the treatment of the future generated ash which are more appropriate to be implemented in Greece are highlighted in the present paper. The performed analysis offers a waste management approach, having 2016 as a reference year for two different incineration rates; 30% and 100% of the remaining MSW after recycling process. The results focus on the two greater regions of Greece: Attica and Central Macedonia. The quantity of potential future ash generation ranges from 137 to 459 kt for Attica region and from 62 to 207 kt for central Macedonia region depending on the incineration rate applied. Three alternative scenarios for the treatment of each kind of ash are compiled and analysed. Metal recovery and reuse as an aggregate in concrete construction proved to be the most advantageous -in terms of economy-bottom ash management scenario. Concerning management of the fly ash, chemical treatment with phosphoric solution addition results to be the lowest total treatment cost and is considered as the most profitable solution. The proposed methodology constitutes a safe calculation model for operators of MSW incineration plants regardless of the region or country they are located in.     

A criticism of applications with multi-criteria decision analysis that are used for the site selection for the disposal of municipal solid wastes

The main aim of this study is to criticize the process of selecting the most appropriate site for the disposal of municipal solid wastes which is one of the problematic issues of waste management operations. These kinds of problems are pathological symptoms of existing problematical human–nature relationship which is related to the syndrome called ecological crisis. In this regard, solving the site selection problem, which is just a small part of a larger entity, for the good of ecological rationality and social justice is only possible by founding a new and extensive type of human–nature relationship. In this study, as a problematic point regarding the discussions on ecological problems, the existing structure of the applications using multi-criteria decision analysis in the process of site selection with three main criteria is criticized. Based on this critique, fundamental problematic points (to which applications are insufficient to find solutions) will be defined. Later, some modifications will be suggested in order to provide solutions to these problematical points. Finally, the criticism addressed to the structure of the method with three main criteria and the feasibility of the new method with four main criteria is subjected to an evaluation process. As a result, it is emphasized that the new structure with four main criteria may be effective in solution of the fundamental problematic points.     

An LCA model for waste incineration enhanced with new technologies for metal recovery and application to the case of Switzerland

A process model of municipal solid waste incinerators (MSWIs) and new technologies for metal recovery from combustion residues was developed. The environmental impact is modeled as a function of waste composition as well as waste treatment and material recovery technologies. The model includes combustion with a grate incinerator, several flue gas treatment technologies, electricity and steam production from waste heat recovery, metal recovery from slag and fly ash, and landfilling of residues and can be tailored to specific plants and sites (software tools can be downloaded free of charge). Application of the model to Switzerland shows that the treatment of one tonne of municipal solid waste results on average in 425 kg CO₂-eq. generated in the incineration process, and 54 kg CO₂-eq. accrue in upstream processes such as waste transport and the production of operating materials. Downstream processes, i.e. residue disposal, generates 5 kg CO₂-eq. Savings from energy recovery are in the range of 67 to 752 kg CO₂-eq. depending on the assumptions regarding the substituted energy production, while the recovery of metals from slag and fly ash currently results in a net saving of approximately 35 kg CO₂-eq. A similar impact pattern is observed when assessing the MSWI model for aggregated environmental impacts (ReCiPe) and for non-renewable resource consumption (cumulative exergy demand), except that direct emissions have less and no relevance, respectively, on the total score. The study illustrates that MSWI plants can be an important element of industrial ecology as they provide waste disposal services and can help to close material and energetic cycles.     

国内温室气体减排:基本框架设计的生态经济问题——与刘世锦等商榷

碳中和是节能减排的生态机制及碳均衡的基础,新能源替代是化石能源枯竭前的必须及节能减排的根本,而直接的节能减排是近期、初期、最多中期的过渡手段。因此国内温室气体减排基本框架设计的方向,应该是在生态经济、循环经济及低碳社会转型中的节能减排、新能源替代和碳中和三方面通盘考虑的基础上,巧妙使用价格杠杆的作用,才能达到"建立起促进技术进步、经济增长和发展方式转变的新机制"的效果。建立带有经济杠杆形式的"碳排放权交易市场",运用"碳源"及"碳汇"的主观价格及市场均衡价格作为灵敏度调节的"手柄"或"砝码",甚至可以"内生性"而不是"外科手术"式地一揽子解决老少边穷地区脱贫问题、退耕还林问题、森林分类经营及生态效益补偿问题、产业的"双转移"问题、主功能区规划中"限制开发区"的生存机制问题、各种企业的高碳能源"碳排放"问题,以及国家层面的新能源基本替代及最大幅度的节能减排之根本问题。     

Integration of the Pesticide Impact Rating Index with a Geographic Information System for the Assessment of Pesticide Impact on Water Quality

The pesticide impact rating index (PIRI) has been integrated with a Geographic Information System (GIS) to enable regional assessment of pesticide impact on groundwater and surface water resources. The GIS version of PIRI (PIRI-GIS) was used to assess the impact of pre-planting atrazine use in the pine plantations on the Gnangara Mound, Western Australia. The impact on groundwater was found to be spatially variable, mainly dependent on soil type and depth to groundwater, because land use variables were spatially constant. Areas with the greatest impact on groundwater were those where the soil had a low sorption capacity for atrazine. Knowledge of the spatial distribution of the sorption coefficient based on organic carbon (K _oc) for atrazine was found to significantly improve the results from PIRI-GIS. Average values for K _oc (i.e. based on overseas data) were too low for most of the local soil types, resulting in a general overestimation of pesticide impact on groundwater resources, but an underestimation of impact in areas that should be of greatest concern (i.e. where the soil has a low sorption capacity for atrazine).