Improving petroleum contaminated land remediation decision-making through the MCA weighting process

Internationally petroleum contamination is widespread, posing serious environmental risks including surface and groundwater contamination, thus remediation is essential. The implementation of remediation options is becoming more complex with the increasing influence of stakeholders on the outcome of decision-making processes. Acceptance of remediation schemes during implementation can be increased by involving stakeholders and the public in the decision-making stage. In petroleum remediation involving multiple stakeholders, Multicriteria Analysis has been employed due to its ability to incorporate the preferences of each stakeholder through weighting. The research focused on investigating ways to improve the weighting process. The study demonstrated the utility of SWING, and determined which type of participant and how many participants to include in the decision process, through the application of ELECTRE III and Weighted Summation. It was recommended that a mixture of stakeholders, the public and experts be involved. The total number of participants will be limited by the choice of participatory and weighting methods. The careful selection of participants, as well as the choice of participatory and weighting methods, can minimize the subjectivity involved in MCA weighting, thereby lending decisions in petroleum remediation greater legitimacy.     

Socioeconomic Dimensions of Changes in the Agricultural Landscape of the Mediterranean Basin: A Case Study of the Abandonment of Cultivation Terraces on Nisyros Island,Greece

Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published literature, as well as surveys of the islanders. Population increases during the late 19^th to early 20^th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4% of the island. By the mid-20^th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes) and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including those on other islands in this region. The island’s unique terraced landscapes may qualify Nisyros to become an archive or repository of old agricultural management techniques to be used by future generations and a living resource for sustainable management.     

Evaluation of the potential for the natural attenuation of hexavalent chromium within a sub-wetland ground water

In this work, the potential for natural attenuation (NA) of Cr(VI) is evaluated for sub-wetland ground water at a chromium-contaminated site in Connecticut, incorporating the experimental findings of previous work at the site. Experimental data is assessed through long-term attenuation capacity calculations and modeling, which incorporates statistical uncertainty of parametric values. The NA evaluation yielded the following results: (1) Significant increases in Cr(VI) concentration and extremely long chromium source dissolution timeframes are required to exceed the attenuation capacity of the sub-wetland region soils studied in this work; and (2) Based on the 1-D transport modeling and incorporating input parameter uncertainty, there is an approximately 92% and 98% probability that the applicable regulatory criteria will not be exceeded at Point C, near a river which serves as the receptor, for the cases of (1) sorption of Cr(VI) only and (2) pseudo first order disappearance of Cr(VI) from the aqueous phase only, respectively.     

Distribution and sources of polycyclic aromatic hydrocarbons in the middle and lower reaches of the Yellow River, China

In this study, concentrations, distribution between different phases, transition along the Middle and Lower reaches of the Yellow River and possible sources of PAHs were assessed. Results demonstrated that the relative proportions of 15 PAHs in all stations of the main River were similar, with concentrations of benzo[a]pyrene all above drinking water standards in most of the stations sampled. PAHs concentrations in tributaries were higher than those in the corresponding sites in the main River. PAHs concentrations of suspended particles were mainly correlated with contents of total organic carbon. However, PAHs concentrations in sediments were mainly correlated to the volume of particles with size smaller than 0.01 mm. The distribution of PAHs in all media sampled indicated that sediments could act as a sink/source for PAHs in different sections and source analysis revealed that PAHs mainly originated from coal burning, although in some tributaries PAH inputs could come from combustion of petroleum.     

Influence of soil inorganic amendments on heavy metal accumulation by leafy vegetables

Environmental Science and Pollution Research - The present study aims to assess the effect of four inorganic soil amendments, such as lime (CaCO3), red mud consisting of 75% hematite (Fe2O3),...     

An economic evaluation framework for membrane reactor modules in the presence of uncertainty: The case for process safety investment and risk reduction

A comprehensive Net Present Value (NPV) model has been developed to demonstrate the economic advantages of process safety and risk reduction investments on Pd/Au-based membrane reactors. In particular, the economic viability of Pd/Au-based membrane reactor modules incorporated into Integrated Gasification Combined Cycle (IGCC) plants is evaluated within the aforementioned framework by pro-actively following sound process safety design principles. Sources of irreducible uncertainty (market, technological, operational) as well as safety risk are explicitly recognized, such as the Pd/Au prices, membrane life-time and loss in the power plant capacity factor due to possible accidents. The effect of the above uncertainty drivers on the membrane module cost along with production disruption and associated revenue losses is elucidated using Monte-Carlo simulation techniques that enable the propagation of the above uncertain inputs through the NPV-model, and therefore, generate a more realistic distribution of the process system's value rather than a single-point/estimate that overlooks these uncertainties. Pre-investment on risk reducing measures, such as spare safety relief systems (cautionary redundancy) for membrane reactor modules operating at high pressures (e.g. 50 atm), is shown to be economically more attractive than cases where analogous safety measures are not implemented. Since accidents and possibly catastrophic events do happen in an uncertain world, additional investment on safety measures could ensure a safer and more profitable operation of the process system under consideration giving credence to the thesis that process safety investments may result in enhanced techno-economic performance in the presence of irreducible uncertainties.     

Risk informed optimization of a hazardous material multi-periodic transportation model

This paper presents a systematic framework toward the development of a Transportation Model for Hazardous Materials (HazMat). In practice, the proposed modeling framework is realized through an appropriate generalization of the traditional transportation network problem in the presence of safety constraints that need to be satisfied. The objective is to minimize transportation cost while reducing risks at the desired levels.In particular, the present research study identifies and evaluates different risk factors that influence the HazMat transportation network. Next, the transportation model is depicted graphically using nodes and arcs and optimal conditions are identified by solving the associated minimum cost flow network problem. The results show safety levels that help making informed decisions on choosing the optimal transportation configuration for hazardous material shipments.Within the proposed methodological context, appropriately parameterized simulation studies elucidate the effects of occurrence probabilities of the different risk events on transportation cost. Furthermore, as the appropriate management decisions must consider the effect of actions in one time period on future periods, the proposed model is structured as a multi-periodic model.Finally, the proposed methodological approach is employed to demonstrate the utility of proper analytical tools in decision making and particularly in ensuring that scientifically informed safety procedures are in place while transporting goods that can be potentially proven dangerous to the public and the surroundings.     

Process safety aspects in water-gas-shift (WGS) membrane reactors used for pure hydrogen production

The syngas produced by coal gasification processes can be utilized in Pd-based water-gas-shift membrane reactors for the production of pure H₂. Pd/alloy composite membrane reactors exhibit comparative advantages over traditional packed bed reactors such as simultaneous reaction/separation in one compact unit and increased reaction yields. Furthermore, the development of comprehensive process intensification strategies could further enhance membrane reactor performance resulting in a substantially smaller and functional, inherently safer, environmentally friendlier and more energy efficient process.A systematic non-isothermal modeling framework under both steady state and dynamic/transient conditions for a catalytic high temperature water-gas shift reaction in a Pd-based membrane reactor has been developed to characterize the dynamic behavior of the process system at various operating conditions from a process safety standpoint. In particular, various reaction conditions as well as key process variables such as feed temperature and flow rate, catalyst loading, driving force for H₂ permeation are considered as they are critically related to various safety aspects in the operation of a Pd-based membrane reactor. Within the proposed framework, process parameters and operating conditions which may induce hazards and compromise process safety are identified, analyzed and characterized. Finally, the proposed approach is evaluated through detailed simulation studies in an illustrative case study involving a real Pd-based membrane reactor used for pure hydrogen production and separation that exhibits complex behavior over a wide operating regime.     

Biogas upgrading to methane and removal of volatile organic compounds in a system of zero-valent iron and anaerobic granular sludge

Environmental Science and Pollution Research - The current study presented a novel process of biogas upgrading to biomethane (higher than 97%) based on anaerobic sludge and zero-valent iron (ZVI)...     

Safety certification requirements for domestic robots

Domestic robotics is a growing sector with the potential for a large number of commercial applications. Robotics technologies have been successfully applied in industrial production lines, yet, for them to be successful in a dynamic household environment the need for increased reliability, robustness and other special capabilities become paramount. We are not far from the time when people will live and interact with robots and, thus, safety becoming the fundamental issue to observe. Robot designers should produce safe products for humans no matter what failure, malfunction or mishandle may occur. Thus, respective safety procedures ought to be applied to domestic robots as well. The most critical challenge is to preserve safety of humans without forfeiting a single token of the efficiency required to perform any task. In this technical communication, the authors address the need for safety regulations in domestic robotics and, while they do not intend to replace any current robot safety standards or guidelines, the proposed work may serve as a supplement to the standards. Since specific safety standards for domestic robots are not available, we propose that their safety verification should be carried out on the base of well-applied standards that developed in other areas and discussed here. The communication in hand provides the ground upon which a standard on domestic robots can be built. Moreover, it proposes a systemic approach that explicitly relates the system and user requirements to a list of safety problems, in order to achieve an adequate level of safety in domestic robotics.