Case study of ex situ remediation and conversion to a combined in situ/ex situ bioremediation approach at an oxygenated gasoline release site

In response to an oxygenated gasoline release at a gas station site in New Hampshire, a temporary treatment system consisting of a single bedrock extraction well, a product recovery pump, an air stripper, and carbon polishing units was installed. However, this system was ineffective at removing tertiary butyl alcohol from groundwater. The subsequent remedial system design featured multiple bedrock extraction wells and an ex situ treatment system that included an air stripper, a fluidized bed bioreactor, and carbon polishing units. Treated effluent was initially discharged to surface water. Periodic evaluation of the remediation system performance led to system modifications, which included installing an additional extraction well to draw contaminated groundwater away from an on‐site water supply well, adding an iron and manganese pretreatment system, and discharge of treated effluent to an on‐site drywell. Later, the air stripper and carbon units were eliminated, and an infiltration gallery was installed to receive treated, oxygenated effluent in order to promote flushing of the smear zone and in situ bioremediation in the source area. This article discusses the design, operation, performance, and modifications to the remediation system over time, and provides recommendations for similar sites. © 2007 Wiley Periodicals, Inc.     

我国再生资源回收体系建设现状、问题及路径选择

再生资源回收体系建设是我国资源综合利用与循环经济重要的组成部分,先进、规范、完整的回收体系是推进再生资源产业发展的关键所在。总结、分析我国再生资源回收体系建设的现状和存在问题,科学地提出建立高效规范回收体系的路径选择,是当前需要研究的一项重要课题。     

Three-Dimensional Ground-Based Measurements of Urban Air Quality to Evaluate Satellite Derived Interpretations for Urban Air Pollution

Urban air quality and meteorological measurements were carried out in the region of Brescia (Italy) simultaneously to the acquisition of satellite data during winter and summer smog conditions in 1999. The main objectives of the campaigns were: delivery of data for the validation of air pollution interpretations based on satellite imagery, and determination of the aerosol optical thickness in spectral ranges similar to those used by satellites. During the winter campaign the ground-based network was complemented by local stations and by SODAR, DOAS, and FTIR remote sensing measurements. Size distributions of aerosol particles up to 4,000 m a.s.l. were measured by means of an ultra-light aircraft, which was also equipped with meteorological sensors and an ozone sensor. During the summer campaign an interference filter actinometer, an integrating nephelometer and an ozone LIDAR were operated additionally. The satellite images acquired and processed were taken from SPOT. Optical thickness retrieved from interference filter actinometer measurements were compared with the retrievals from the satellite imagery in the same spectral intervals. It is concluded that remaining aerosols in the reference image yield an off-set in the satellite retrieval data and that information about the vertical structure of the boundary layer is very important.     

Effect of Degree of Substitution of Octenyl Succinate Starch on the Emulsification Activity on Different Oil Phases

Octenyl succinic starch (OSA starch) was synthesized from an aqueous medium and pyridine medium using previously established literature methods. Such a substitution would conceivably impart some hydrophobicity to the already hydrophilic starch chain. Thus, an amphiphilic character could be introduced wherein while the water solubility of the final product would be retained or enhanced, interactions with hydrophobic phases could be enhanced. These products find a variety of applications. The emulsifying activity of OSA starch was tested against different oil phases. It was found that the activity was dependent on the oil phase chosen. The activity was largely independent of the concentration of the substrates when the modification was conducted in an aqueous medium. Products from an organic medium did show an increase in activity with concentration. This difference in activity was attributed to the molecular weight of the final product, which seemed to be lower for the products from an organic medium as suggested by viscometry. The granular state of starch could also have a great effect on the properties of modified starch.     

Impact of the Jatoba shell residue amount on polyurethane foams based on castor polyol

Journal of Material Cycles and Waste Management - This study proposes an alternative for Jatoba shell residues as reinforcement in castor oil-based polyurethane (PU), obtaining an eco-friendly...     

Evaluation of the Effect of Chemical or Enzymatic Synthesis Methods on Biodegradability of Polyesters

This work compares the biodegradability of polyesters produced by an esterification reaction between glycerol and oleic di-acid (D 18:1) issued from green chemical pathways, via either classical thermo-chemical methods, or an enzymatic method using the immobilized lipase of Candida antartica B (Novozym 435). An elastomeric polymer synthesized by enzymatic catalysis is more biodegradable than an elastomeric thermo-chemical polyester synthesized by a standard chemical procedure. This difference lies in percentage of the dendritic motifs, in values of the degree of substitution, and certainly in cross-links inducing an hyper-branched structure less accessible to the lipolytic enzymes in a waste treatment plant. However, when the elastomeric polymer synthesized by enzymatic catalysis is processed at high temperature as required for certain industrial applications, it presents an identical rate of biodegradation than the chemical polyester. The advantages of the thermo-chemical methods are greater speed and lower cost. Enzymatic synthesis appears be suited to producing polyesters, devoid of metallic catalysts, which must be used without processing at high temperature to keep a high biodegradability.     

Characteristics, treatment and utilization of residues from municipal waste incineration

Beneficial utilization of residues from municipal solid waste incineration is an important objective for integrated waste management in many jurisdictions. When residues are to be used as an aggregate substitute in construction applications, the release of constituents of concern to soils and water through leaching is an important environmental consideration. In this paper, residue characteristics that control constituent leaching and testing approaches for evaluating leaching are discussed. Quality control and potential improvement in case of beneficial application are addressed.     

Evaluation of the waste heat discharged from the Di-ammonium Phosphate production plant: a case study

Journal of Material Cycles and Waste Management - This work presents an energy analysis of an industrial plant of production of Di-ammonium Phosphate (DAP plant). It aims to evaluate the important...     

Fluidized bed PCB incineration in Alaska

Ogden Environmental Services Inc. (OES) is operating a PCB incineration project on the Kenai Peninsula, Alaska. The facility is approximately 150 miles from Anchorage, Alaska, on a U.S. Fish and Wildlife Service refuge and recreation area. Before attaining its current status, the area was an oil field; pipelines and compressor stations are still in the area. Ogden's facilities are located adjacent to an operating compressor station in an area transected by pipelines. The site became contaminated with PCBs as an indirect result of a compressor explosion in 1972. In March 1988 OES contracted to remediate the site using its proprietary transportable Circulating Bed Combustor (CBC), an advanced technology fluidized bed incinerator. The project will thermally treat more than 80,000 tons of PCB-contaminated soil. Treated soil (ash) contains less than 0.1 ppm PCB and is permanently placed on site. Ogden designed, constructed, permitted, conducted trial burns, and made fully operational this major facility on the remote Kenai Peninsula of Alaska. All systems were designed to withstand the rigors of shipping and to be highly reliable in cold weather and remote-site operations.     

Bio‐Based Poly(3-hydroxybutyrate)/Thermoplastic Starch Composites as a Host Matrix for Biochar Fillers

Journal of Polymers and the Environment - Biochar is an excellent, but less-used candidate to serve as an alternative filler in poly(3-hydroxybutyrate) (PHB)-based composites. Increasing amounts of...     

Biodegradable corn starch loose- fill. I. The effect of the extrusion temperature on the physical properties of loose-fill

Extrusion with an intermeshing corotating twin-screw extruder with a limited amount of water caused structural changes in corn starch. The structural changes resulted in a transformation-from a semicrystalline to an amorphous state and the development of orientation of molecular chains in the amorphous region during extrusion. These structural changes, in turn, caused an increase in theT _g, tensile strength, and resilience of the extruded corn starch. Our experimental results showed that the tensile properties and resilience of the expanded corn starch extruded at 240‡C were the best: tensile strength, 1.7 kPa; tensile modulus, 40.4 kPa; and resilience, 57.2%. Extrusion produced an expanded corn starch suitable for protective loose-fill.     

Kinetics of thermal de-chlorination of PVC under pyrolytic conditions

Although PVC-containing wastes are an important potential source of energy they are frequently disposed in landfill. In thermal treatment processes such as pyrolysis and gasification, the presence of poly(vinyl chloride) (PVC), a compound with 56.7% of chlorine, may cause problems concerned with environmental protection, as consequence of the formation of hydrochloric acid, chlorine gas and dioxins, as well as corrosion phenomena of the reactor/equipment materials. Thus, a possible solution may involve a previous removal of the chlorine from PVC containing waste through a pyrolysis process at low temperatures before the material being submitted to a subsequent thermal treatment, for energetic valorization. In this work, a kinetic model for the thermal decomposition of PVC has been developed, in view of its de-chlorination. DTA/TGA testing at different temperatures indicated a first order reaction and an activation energy of 133,800J/mol. An almost completed de-chlorination reaction was obtained at 340°C under an inert atmosphere. The resulted material is a C(n)H(n) type polymer with potential to be used in an energy recovery process. Validation test performed at laboratory scale indicate that the temperature of 340°C enables the removal of ～99.9% of the chlorine present in PVC. The chloride can be fixed in the form of an aqueous solution of HCl or calcium chloride, driving to an alternative full process with environmental benefits and reduction of the costs associated to the PCV - containing materials/wastes management.     

Model predictive control as a tool for improving the process operation of MSW combustion plants

In this paper a feasibility study is presented on the application of the advanced control strategy called model predictive control (MPC) as a tool for obtaining improved process operation performance for municipal solid waste (MSW) combustion plants. The paper starts with a discussion of the operational objectives and control of such plants, from which a motivation follows for applying MPC to them. This is followed by a discussion on the basic idea behind this advanced control strategy. After that, an MPC-based combustion control system is proposed aimed at tackling a typical MSW combustion control problem and, using this proposed control system, an assessment is made of the improvement in performance that an MPC-based MSW combustion control system can provide in comparison to conventional MSW combustion control systems. This assessment is based on simulations using an experimentally obtained process and disturbance model of a real-life large-scale MSW combustion plant.     

基于灰色关联度的西安市水环境承载力状况评价

结合西安市生态社会经济现状,建立与水环境系统密切相关的承载力指标体系;采用AHP法分析确定评价指标的权重,应用灰色关联度法和模糊综合评判构建水环境承载力评价模型,收集近年数据对西安市水环境承载力进行现状评价。结果表明,西安市水环境承载力从2000年的脆弱到2009年的良好大致呈现连年增强的趋势。但从隶属度矩阵发现,增长的动力来源于经济的良好发展势头,而生态系统已经遭到较严重的破坏,且修复不利,同时科技发展对承载力的贡献也呈现逐年下降趋势。研究表明,解决西安市水环境未来面临的恶化趋势的关键在于加速雨水资源化进程推进。     

Fast-track remediation for redevelopment of a former integrated steel mill site

Remedial action was initiated and completed on an approximately 500-acre brownfield site in southern California within a period of five months during the summer of 1995. Remedial actions included design and construction of an approximately 14-acre cap, including a synthetic membrane; design, construction, and testing of an in-situ soil vapor extraction system; excavation, on-site treatment, and off-site disposal of approximately 7,000 cubic yards of residual waste and affected soil; and verification sampling, analysis, and health risk screening in 20 units of a former integrated steel mill. Completion of remedial action on this portion of the mill site within this time frame was required due to site redevelopment plans which included construction of an auto raceway with scheduled races in early 1997. Rapid remedial action was possible only through simultaneous completion of multiple remediation tasks. This could be done only with continuous communication and close coordination among the site owner, lead regulatory agency, and contractors.     

Odour management and treatment technologies: an overview

There is a large variety of options available for the effective treatment of odorous emissions. The most important physical, chemical and biological treatment processes are shortly described and their favourable applications, as well as their limits, are highlighted. But for a sustainable solution of an industrial odour problem, there is more involved than just the installation of a waste gas treatment system. This article focuses on a general and systematic approach towards extensive odour management. First of all, an odour assessment should be worked out where all actual and potential odour emission sources are recorded and characterised. A special focus should be set on fugitive emissions, which may have an enormous impact on the overall odour problem. They need to be captured before they can be supplied to a treatment system. According to the composition and condition of the waste gases, an appropriate treatment system must be selected. For this purpose, test systems have been developed and are presented in this article.     

Photo-oxidation and Photo-toxicity of Crude and Refined Oils

The fate and effects of an oil spill are effected by solar radiation through the action of photo-oxidation and photo-toxicity. Photo-oxidation, an important process in the weathering of oil, produces a variety of oxidized compounds, including aliphatic and aromatic ketones, aldehydes, carboxylic acids, fatty acids, esters, epoxides, sulfoxides, sulfones, phenols, anhydrides, quinones and aliphatic and aromatic alcohols. Some of these compounds contribute to the marine biota toxicity observed after an oil spill. Photo-toxicity occurs when uptake of certain petroleum compounds, e.g. certain polycyclic aromatic hydrocarbons and benzothiophenes, is followed by solar exposure which results in much greater toxicity than after dark uptake. The mechanism of PAH photo-toxicity includes absorbance of solar radiation by the PAH which produces a free radical and this free radical in turn reacts with oxygen to produce reactive oxygen species that can damage DNA and other cellular macromolecules. While most studies on photo-toxicity have been carried out in the laboratory, there are studies showing that water from an oil spill is photo-toxic to bivalve embryos for at least a few days after the spill. Other studies have found that oil contaminated sediments are photo-toxic to several marine invertebrates. More studies are required to determine if marine fauna at an oil spill site are effected by the action of photo-toxicity and photo-oxidation.     

Biobased Epoxy/Layered Silicate Nanocomposites: Thermophysical Properties and Fracture Behavior Evaluation

The biobased epoxy containing epoxidized linseed oil (ELO) and its clay nanocomposites were processed with an anhydride curing agent. The certain amount of diglycidyl ether of bisphenol F (DGEBF) was replaced by ELO. The selection of the DGEBF, ELO, an anhydride curing agent, and organo-montmorillonite clay resulted in an excellent combination, to provide new biobased epoxy/clay nanocomposites showing high elastic modulus, high glass transition temperature, and high fracture toughness with larger amount of ELO. Izod impact strength was almost constant while changing the amount of ELO. This is a promising result for future applications in different engineering industries.     

Nanocomposites of Waterborne Polyurethane Reinforced with Cellulose Nanocrystals from Sisal Fibres

Cellulose nanocrystals (CNC) were isolated from sisal fibres and were incorporated in the form of an aqueous suspension to a waterborne polyurethane (WBPU) synthesized from components derived from natural sources using an aliphatic diisocyanate. Transparent nanocomposite films with different CNC contents were prepared using a casting method. The morphology, thermal behaviour and mechanical properties of the nanocomposite films were characterized. Homogeneous distribution of CNC in the WBPU, even at high CNC contents was observed, resulting in an increase of 100% in modulus for systems with 5 and 10 wt% of CNC, with high elongations around 650%.     

Energy recovery from municipal waste: a case study for a middle-sized Italian district

This paper reports the main outcome of research to compare and assess the merits of alternative strategies for energy recovery from municipal solid waste downstream of material recovery for an Italian province. Strategies analysed are based on well-established combustion technologies available at the commercial scale in the Italian market in comparison with an innovative but not yet proven option of refuse derived fuel gasification and subsequent co-combustion of syngas in a combined cycle power plant. The comparison is made using mass and energy balances, environmental assessment and economic analysis. From an energetic point of view, the best strategy is the one based on the refuse derived fuel gasification, which, on the contrary, does not show interesting environmental results. In this perspective, the best results are from strategies based on a dedicated plant, particularly when unsorted residual waste collected downstream of material recovery is used. Finally, from an economic point of view, the strategy with gasification allows the highest revenues from the sale of energy.