Michael R. Overcash

Fate of polynuclear aromatic compounds (PNAs) in soil-plant systems

Polycyclic aromatic hydrocarbons (PAH) consist of three or more fused benzene rings in linear, angular, or cluster arrangements. Substitution of carbon in the benzene ring with nitrogen, sulfur, oxygen, or other elements creates heterocyclic aromatic compounds (Blumer 1976). Excluding diphenyl types there are some 70 possible isomers of 4-6 fused rings. Additionally these isomers may be substituted by a variety of substituents (Erskine and Whitehead 1975). The aromatic hydrocarbons and heterocycles, unsubstituted and substituted, are referred to alternatively as polynuclear aromatics (PNAs), polycyclic aromatic compounds (PCAs), and polycyclic organic matter (POM) (NAS 1972, U.S. EPA 1975 b).

Methodology for developing gate-to-gate Life cycle inventory information

Life Cycle Assessment (LCA) methodology evaluates holistically the environmental consequences of a product system or activity, by quantifying the energy and materials used, the wastes released to the environment, and assessing the environmental impacts of those energy, materials and wastes. Despite the international focus on environmental impact and LCA, the quality of the underlying life cycle inventory data is at least as, if not more, important than the more qualitative LCA process.This work presents an option to generate gate-to-gate life cycle information of chemical substances, based on a transparent methodology of chemical engineering process design (an ab initio approach). In the broader concept of a Life Cycle Inventory (LCI), the information of each gate-to-gate module can be linked accordingly in a production chain, including the extraction of raw materials, transportation, disposal, reuse, etc. to provide a full cradle to gate evaluation. The goal of this article is to explain the methodology rather than to provide a tutorial on the techniques used. This methodology aims to help the LCA practitioner to obtain a fair and transparent estimate of LCI data when the information is not readily available from industry or literature. Results of gate-to-gate life cycle information generated using the cited methodology are presented as a case study.It has been our experience that both LCI and LCA information provide valuable means of understanding the net environmental consequence of any technology. The LCI information from this methodology can be used more directly in exploring engineering and chemistry changes to improve manufacturing processes. The LCA information can be used to set broader policy and to look at more macro improvements for the environment.

Methodology for systematic analysis and improvement of manufacturing unit process life cycle inventory (UPLCI) Part 1: Methodology Description

PurposeThis report proposes a life-cycle analysis (LCA)-oriented methodology for systematic inventory analysis of the use phase of manufacturing unit processes providing unit process datasets to be used in life-cycle inventory (LCI) databases and libraries. The methodology has been developed in the framework of the CO2PE! collaborative research programme (CO2PE! 2011a) and comprises two approaches with different levels of detail, respectively referred to as the screening approach and the in-depth approach.MethodsThe screening approach relies on representative, publicly available data and engineering calculations for energy use, material loss, and identification of variables for improvement, while the in-depth approach is subdivided into four modules, including a time study, a power consumption study, a consumables study and an emissions study, in which all relevant process in- and outputs are measured and analysed in detail. The screening approach provides the first insight in the unit process and results in a set of approximate LCI data, which also serve to guide the more detailed and complete in-depth approach leading to more accurate LCI data as well as the identification of potential for energy and resource efficiency improvements of the manufacturing unit process. To ensure optimal reproducibility and applicability, documentation guidelines for data and metadata are included in both approaches. Guidance on definition of functional unit and reference flow as well as on determination of system boundaries specifies the generic goal and scope definition requirements according to ISO 14040 (2006) and ISO 14044 (2006).ResultsThe proposed methodology aims at ensuring solid foundations for the provision of high-quality LCI data for the use phase of manufacturing unit processes. Envisaged usage encompasses the provision of high-quality data for LCA studies of products using these unit process datasets for the manufacturing processes, as well as the in-depth analysis of individual manufacturing unit processes.ConclusionsIn addition, the accruing availability of data for a range of similar machines (same process, different suppliers and machine capacities) will allow the establishment of parametric emission and resource use estimation models for a more streamlined LCA of products including reliable manufacturing process data. Both approaches have already provided useful results in some initial case studies (Kellens et al. 2009; Duflou et al. (Int J Sustain Manufacturing 2:80–98, 2010); Santos et al. (J Clean Prod 19:356–364, 2011); UPLCI 2011; Kellens et al. 2011a) and the use will be illustrated by two case studies in Part 2 of this paper (Kellens et al. 2011b).

Fate of polychlorinated biphenyls (PCBs) in soil-plant systems.

Polychlorinated biphenyls (PCBs) are a class of chlorinated aromatic hydrocarbons which are thermally and chemically very stable. The PCBs represent a mixture of specific biphenyl hydrocarbons with varying degrees of chlorination. Substitution for hydrogen on the ring structure of biphenyl by chlorine gives rise to a number of compounds and isomers with 209 possible combinations (HUTZINGER et al.1974). The nomenclature of chlorobiphenyls is based on the position and extent of substitution on the biphenyl ring structure as shown in Figure 1. The available sites for chlorination are 2 to 6 in ring A and 2′ to 6′ in ring B. Thus, chlorobiphenyls may carry 1 to 10 chlorine atoms, depending on the degree of chlorination. Usually in commercial preparations, different mixtures of chlorobiphenyls are produced rather than a single pure compound. Typical characteristics of polychlorinated biphenyls (PCBs) are high thermal and chemical stability, low vapor pressure, high dielectric constant, high electric resistivity, high density, substantially hydrophobic, and high lipophilicity. With increasing chlorination from 18.6% to 80% these properties are accentuated. Molecular weights of PCBs range from 188 for monochlorobiphenyl to 494 for decachlorobiphenyl. Their melting points range from 34° to 198°C and boiling points are usually 267°C. Appearances of PCBs range from clear mobile oils to light yellow, sticky, solid resins. PCBs are quite soluble in nonionic surfactants such as ethylene oxide, Tween 201 and Tween 80.

Methodology for systematic analysis and improvement of manufacturing unit process life cycle inventory (UPLCI) Part 2: Case Studies

PurposeThis report presents two case studies, one for both the screening approach and the in-depth approach, demonstrating the application of the life cycle assessment-oriented methodology for systematic inventory analysis of the machine tool use phase of manufacturing unit processes, which has been developed in the framework of the CO2PE! collaborative research programme (CO2PE! 2011) and is described in part 1 of this paper (Kellens et al. 2011).Screening approachThe screening approach, which provides a first insight into the unit process and results in a set of approximate LCI data, relies on representative industrial data and engineering calculations for energy use and material loss. This approach is illustrated by means of a case study of a drilling process.In-depth approachThe in-depth approach, which leads to more accurate LCI data as well as the identification of potential for environmental improvements of the manufacturing unit processes, is subdivided into four modules, including a time study, a power consumption study, a consumables study and an emissions study, in which all relevant process in- and outputs are measured and analysed in detail. The procedure of this approach, together with the proposed CO2PE! template, is illustrated by means of a case study of a laser cutting process.ResultsThe CO2PE! methodology aims to provide high-quality LCI data for the machine tool use phase of manufacturing unit processes, to be used in life cycle inventory databases and libraries, as well as to identify potential for environmental improvement based on the in-depth analysis of individual manufacturing unit processes. Two case studies illustrate the applicability of the methodology.

Biological activities of 2,4-dinitrophenol in plant-soil systems

2,4-Dinitrophenol (DNP)is a phenol prepared by alkaline hydrolysis of 2,4-dinitro-1-chlorobenzene which in turn is prepared from the nitration of monochlorobenzene (Hartford 1973). Alternative routes of preparation are by nitration of monochlorobenzene (Hartford 1973). Alternative routes of preparation are by nitration of benzene with NO2 and mercurous nitrate or by the oxidation of m-dinitrobenzene. Pure DNP is a solid of yellowish to yellow orthorhombic crystals, with molecular weight 184.11, density 1.683 g/ml, and melting point of 115° to 116°C (Windholz 1976). It has a water solubility of 6.0 g/L at 25°C (Morrison and Boyd 1973). DNP is soluble in most organic solvents and essentially nonvolatile, but does sublime at temperatures above its melting point (Windholz 1976). The compound is moderately acidic, with a pKA of 4.09 and ionizes as shown in Figure 1 (Pearce and Simpkins 1968). At pH 2.6, DNP is colorless but becomes yellow in solution at pH 4.4 and hence has been used as an indicator (Windholz 1976). DNP can also be used as a reagent to detect potassium and ammonium ions.

Life Cycle Assessment Study of Color Computer Monitor

The environmental performance of a color computer monitor is investigated by implementing a Life Cycle Assessment. The goal of this study is to collect LCI data of foreground systems, to identify hot spots, and to introduce life cycle thinking at the product design stage. Secondary data are used in the background system, and site-specific data are collected in the foreground system.Results show that the use phase is the most contributing phase. The operating mode and the energy saving mode during the overall use phase contribute to the total by 59% and by 9.9%, respectively. In the production phase, the cathode ray tube assembly process and the printed circuit board assembly process are the most contributing processes. The sensitivity analysis on the use pattern scenario shows that the contribution ratio of the use phase ranges from 32% to 84%. Even in the home use case, which is the best case scenario, the use phase is one of the most contributing processes to the environmental performance of the color computer monitor. There is no significant difference in the choice of the impact assessment methodologies for identifying the improvement opportunities.For the external use of Life Cycle Assessment in a short-run product for the market, it is recommended that Life Cycle Assessment should be carried out in parallel with the product design stage. It is also necessary to have a pre-existing, in-house database for a product group in order to accelerate life cycle procedures.

Allocation procedure in multi-output process: an illustration of ISO 14041

Allocation results for a multi-output process in a life cycle assessment study depend on the definition of the unit process which can vary with the depth of a study. The unit process may be a manufacturing site, a sub-process, or an operational unit (e.g. distillation column or reactor). There are three different approaches to define a unit process: macroscopic approach, quasi-microscopic approach, and microscopic approach. In the macroscopic approach, a unit process is the manufacturing site, while a unit process in the quasi-microscopic approach is a sub-process of the manufacturing site. An operational unit becomes the unit process in the microscopic approach.In the quasi-microscopic and the microscopic approaches, a process can be subdivided into a joint process, a physically separated process which is physically apart from other processes, and a fully separated process. Each type can be a unit process. Therefore, the multi-output process in the quasi-microscopic and the microscopic approaches can be subdivided among two or more unit processes depending on the actual operations.The allocation in the fully separated process can be avoided because this process fulfills one function. In the joint process and the physically separated process, which deliver two or more functions, allocation is still required.Ammonia manufacturing, where carbon dioxide is formed as a byproduct is given to show a specific detailed example of the allocation procedure by subdivision in ISO 14041. It is shown that the quasi-microscopic and the microscopic approaches can reduce the multi-output allocation of a given chemical product. Furthermore, the quasi-microscopic and the microscopic approaches are very useful in identifying key pollution prevention issues related with one product or function.

How do you select the “greenest” technology? Development of guidance for the pharmaceutical industry

There is widespread interest in government and industry in green chemistry and green technology. For truly “green” processes to be developed, scientists must take a concurrent, integrated approach that considers chemistry and technology. While it is vital to understand those things traditionally considered in technology selection such as operational, quality, and cost differences, it is equally vital to understand the associated environmental and safety issues that are inherent to the chosen technology. This is a major challenge and there is a clear need for guidance in this area. This paper proposes the concept of a “Clean/Green Technology Guide” as an expert system that would provide scientists and engineers with comparative environmental and safety performance information on available technologies for commonly performed unit operations in the pharmaceutical industry. At this stage, the framework has been developed to demonstrate the concept, using a metric set based on the concepts of sustainable development. This framework is used to evaluate the alternatives on a case-scenario basis, and will compare traditional and emerging technologies. A life-cycle approach is also used in the evaluation of the alternatives. This approach is illustrated by comparing batch, mini-, and microreactors.

Demonstration of photodegradation by sunlight of 2,3,7,8-tetrachlorodibenzo-p-dioxin in 6 cm soil columns

An in situ process, requiring only solvent addition and sunlight exposure, for treatment of soil sites contaminated with TCDD was successfully demonstrated. Substantial photodegradation (60% to 85%) of the total TCDD was found after 60 days of exposure.