The integration of trajectory models and analysis into spill response information systems

The spill response community is engaged in a technological rush towards computer-based, information-synthesis systems. Typically, they are modeled after many successful ‘incident command’ or ‘command and control’ systems that rely on micro- or mini-computer technology that is friendly and graphically oriented. Virtually all of these systems offer spill trajectory modeling components. What is typically lacking in this modeling output is any reliable way to estimate the uncertainty. This means that advice derived from the models is of questionable value, and when integrated into a complex response plan, the propagation of errors could seriously compromise the usefulness of results. It is shown that no single trajectory model run can provide the necessary information to respond in an optimal, ‘minimum regret’ strategy. However, a well-defined series of model runs used as the basis for trajectory analysis can provide the required information. A discussion of options suggests that the adoption of a minimum standard analysis procedure would significantly improve the ability of integrated response systems to use the predictions of oil distributions.     

Analysis of Methods Used in Spill Response Planning: Trajectory Analysis Planner TAP II

Long records of geophysical forcing have been used in numerous studies to estimate a statistical distribution of oil spill scenarios. The resulting set of spill scenarios is then used as a basis for planning a robust response capability that should be able to handle all likely real spills. For model developers to be able to support these expectations there are a number of criteria that must be satisfied: (1) Models must develop and retain the data necessary to answer key response questions; (2) developers must understand the limitations in resolution imposed by the specific algorithms they use; and (3) the cardinality of the long geophysical records (with respect to modeled spill behavior) should be determined and the final collection of spill scenarios must span this set. This paper considers these specific constraints and discusses methods that can be used to quantify some aspects of the uncertainty in the output.     

The application of ecological risk assessment principles to dispersant use planning

Ecological risk assessment is a formal process, either quantitative or semi-quantitative, to evaluate the possible ecological consequences of human activities and natural catastrophes. While formal risk assessments have been used for years when dealing with risks to human health, the application of such structured analyses is less common for environmental issues. It is, however, an area of intense interest, both scientifically and technically, in the United States at the present time. This paper suggests a methodology for applying ecological risk assessment protocols to the oil spill response planning process, which should improve our ability to compare and evaluate response options, especially controversial options such as the use of dispersants.     

Quantitative analysis of alternate oil spill response strategies using OSCAR

A three-dimensional numerical model of the physical and chemical behavior and fate of spilled oil has been coupled to a model of oil spill response actions. This coupled system of models for Oil Spill Contingency and Response (OSCAR), provides a tool for quantitative, objective assessment of alternative oil spill response strategies. Criteria for response effectiveness can be either physical (‘How much oil comes ashore?’ or ‘How much oil have we recovered?’) or biological (‘How many biologically sensitive areas were affected?’ or ‘What exposures will fish eggs and larvae experience in the water column?’). The oil spill combat module in the simulator represents individual sets of equipment, with capabilities and deployment strategies being specified explicitly by the user. The coupling to the oil spill model allows the mass balance of the spill to be affected appropriately in space and time by the cleanup operation as the simulation proceeds. An example application is described to demonstrate system capabilities, which include evaluation of the potential for both surface and subsurface environmental effects. This quantitative, objective approach to analysis of alternative response strategies provides a useful tool for designing more optimal, functional, rational, and cost-effective oil spill contingency solutions for offshore platforms, and coastal terminals and refineries.     

The 1993 oil spill of Tampa Bay,a scenario for burning?

This viewpoint paper considers the potential of offshore burning of oil in the recent Tampa Bay spill as a generic oil spill response option. While the oil spilled might not have been amenable to burning, the physical constraints of the spill and subsequent environmental conditions provide a scenario for future consideration of this option.     

Real time oil spill forecasting during an experimental oil spill in the arctic ice

The oil spill trajectory and weathering model OILMAP was used to forecast spill trajectories for an experimental oil spill in the Barents Sea marginal ice zone. The model includes capabilities to enter graphically and display environmental data governing oil behavior: ice fields, tidal and background current fields, and wind time series, as well as geographical map information. Forecasts can also be updated from observations such as airplane overflights. The model performed well when wind was ‘off-ice’ and speeds were relatively low (3–7 m s⁻¹), with ice cover between 60 and 90%. Errors in forecasting the trajectory could be directly attributed to errors in the wind forecasts. Appropriate drift parameters for oil and ice were about 25% of the wind speed, with an Ekman veering angle of 35° to the right. Ice sheets were typically 1 m thick. When the wind became ‘on-ice’, wind speeds increased to about 10 m s⁻¹ and trajectory simulations began to diverge from the observations, with observed drift parameters being 1.5% of the wind speed, with a 60° veering angle. Although simple assumptions for the large scale movement of oil in dense ice fields appear appropriate, the importance of good wind forecasts as a basis for reliable trajectory prognoses cannot be overstated.     

Modeling the fate of oil spills at sea

A numerical model for the simulation of the physicochemical weathering processes of an oil spill at sea is presented based on state-of-the-art models. The model includes the most significant processes: spreading, evaporation, dispersion into the water column, emulsification and the change in viscosity and density. These processes depend on each other and are allowed to vary simultaneously since processes are described by a set of differential equations, solved by a fourth-order Runge-Kutta method. Numerical examples are given, in order to test the results obtained, and compared with available experimental data in the literature. The model predicts well the variation of water incorporation, density and viscosity but seems to overestimate the fraction evaporated. However more experimental data are needed to calibrate and validate the model since differences in the composition of the simulated oil and the samples from which experimental data are taken may occur in evaporation studies. The model is suitable to join other modules for the prediction of the spill trajectory by advection due to winds and currents and sub-sea transport.     

Comparative occurrence rates for offshore oil spills

Estimates of occurrence rates for offshore oil spills are useful for analysis of potential oil spill impacts and for oil spill response contingency planning. As the Oil Pollution Act of 1990 (U.S. Public Law 101–380, 18 August 1990) becomes fully implemented, estimates of oil spill occurrence will become even more important to natural resource trustees and to responsible parties involved in oil and gas activities. Oil spill occurrence rate estimates have been revised based on U.S. Outer Continental Shelf platform and pipeline spill data (1964–1992) and worldwide tanker spill data (1974–1992). These spill rates are expressed and normalized in terms of number of spills per volume of crude oil handled. The revisions indicate that estimates for the platform spill occurrence rates declined, the pipeline spill occurrence rates increased, and the worldwide tanker spill occurrence rates remained unchanged. Calculated for the first time were estimates of tanker and barge spill rates for spills occuring in U.S. waters, and spill occurrence rates for spills of North Slope crude oil transported by tanker from Valdez, Alaska. All estimates of spill occurrence rates were restricted to spills greater than or equal to 159 m³ (1000 barrels).     

Optimal planning for the sustainable utilization of municipal solid waste

The increasing generation of municipal solid waste (MSW) is a major problem particularly for large urban areas with insufficient landfill capacities and inefficient waste management systems. Several options associated to the supply chain for implementing a MSW management system are available, however to determine the optimal solution several technical, economic, environmental and social aspects must be considered. Therefore, this paper proposes a mathematical programming model for the optimal planning of the supply chain associated to the MSW management system to maximize the economic benefit while accounting for technical and environmental issues. The optimization model simultaneously selects the processing technologies and their location, the distribution of wastes from cities as well as the distribution of products to markets. The problem was formulated as a multi-objective mixed-integer linear programing problem to maximize the profit of the supply chain and the amount of recycled wastes, where the results are showed through Pareto curves that tradeoff economic and environmental aspects. The proposed approach is applied to a case study for the west-central part of Mexico to consider the integration of MSW from several cities to yield useful products. The results show that an integrated utilization of MSW can provide economic, environmental and social benefits.     

Optimal design for sustainable development of a material recovery facility in a fast-growing urban setting

Installing material recovery facilities (MRFs) in a solid waste management system could be a feasible alternative to achieve sustainable development goals in urban areas if current household and curbside recycling cannot prove successful in the long run. This paper addresses the optimal site selection and capacity planning for a MRF in conjunction with an optimal shipping strategy of solid waste streams in a multi-district urban region. Screening of material recovery and disposal capacity alternatives can be achieved in terms of economic feasibility, technology limitation, recycling potential, and site availability. The optimization objectives include economic impacts characterized by recycling income and cost components for waste management, while the constraint set consists of mass balance, capacity limitation, recycling limitation, scale economy, conditionality, and relevant screening constraints. A case study for the City of San Antonio, Texas (USA) presents a vivid example where scenario planning demonstrates the robustness and flexibility of this modeling analysis. It proves especially useful when determining MRF ownership structure. Each scenario experiences two case settings: (1) two MRF sites are proposed for selection and (2) a single MRF site is sought. Cost analysis confirms processing fees are not the driving force in the City's operation, but rather shipping cost. Sensitivity analysis solidifies the notion that significant public participation plays the most important role in minimizing solid waste management expenses.     

COASTMAP: An integrated monitoring and modeling system to support oil spill response

One of the most difficult tasks in oil spill response modeling is to provide accurate estimates of the currents and winds during the spill event. This is typically done in an ad-hoc, subjective manner combining very limited field observations with simplified hydrodynamic and meteorological models. As an alternative an integrated environmental monitoring and modeling system, called COASTMAP, is presented. COASTMAP allows the user to collect, manipulate, display, and archive real-time environmental data through an embedded geographic information system and environmental data management tools; to perform simulations with a suite of environmental models (e.g. hydrodynamics, meteorological) in order to predict dynamics in the operational area and to assimilate real-time data into the models to allow hindcasting, nowcasting and forecasting. COASTMAP, operational on a personal computer, is controlled by mouse/keyboard through a series of menus and uses color graphics to present model predictions (plots, graphs, animations) and the results of data analyses. The software is designed using a shell based architecture making application to any geographic location simple and straightforward.In the present paper, COASTMAP is linked with OILMAP to provide a fully operational, real-time system that allows prediction of circulation, winds and oil spill trajectory and fate for estuarine and coastal sea areas. System performance is illustrated by the simulation of the trajectory of oil tracking buoys during two experiments performed in the lower west passage of Narragansett Bay. Simulation results using several forecast procedures, with/without real-time data, are presented.     

A methodology for optimal MSW management,with an application in the waste transportation of Attica Region,Greece

The paper describes a software system capable of formulating alternative optimal Municipal Solid Wastes (MSWs) management plans, each of which meets a set of constraints that may reflect selected objections and/or wishes of local communities. The objective function to be minimized in each plan is the sum of the annualized capital investment and annual operating cost of all transportation, treatment and final disposal operations involved, taking into consideration the possible income from the sale of products and any other financial incentives or disincentives that may exist. For each plan formulated, the system generates several reports that define the plan, analyze its cost elements and yield an indicative profile of selected types of installations, as well as data files that facilitate the geographic representation of the optimal solution in maps through the use of GIS. A number of these reports compare the technical and economic data from all scenarios considered at the study area, municipality and installation level constituting in effect sensitivity analysis. The generation of alternative plans offers local authorities the opportunity of choice and the results of the sensitivity analysis allow them to choose wisely and with consensus.The paper presents also an application of this software system in the capital Region of Attica in Greece, for the purpose of developing an optimal waste transportation system in line with its approved waste management plan. The formulated plan was able to: (a) serve 113 Municipalities and Communities that generate nearly 2 million t/y of comingled MSW with distinctly different waste collection patterns, (b) take into consideration several existing waste transfer stations (WTS) and optimize their use within the overall plan, (c) select the most appropriate sites among the potentially suitable (new and in use) ones, (d) generate the optimal profile of each WTS proposed, and (e) perform sensitivity analysis so as to define the impact of selected sets of constraints (limitations in the availability of sites and in the capacity of their installations) on the design and cost of the ensuing optimal waste transfer system. The results show that optimal planning offers significant economic savings to municipalities, while reducing at the same time the present levels of traffic, fuel consumptions and air emissions in the congested Athens basin.     

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.     

On the optimal design of the disassembly and recovery processes

This paper tackles the problem of the optimal design of the recovery processes of the end-of-life (EOL) electric and electronic products, with a special focus on the disassembly issues. The objective is to recover as much ecological and economic value as possible, and to reduce the overall produced quantities of waste. In this context, a medium-range tactical problem is defined and a novel two-phased algorithm is presented for a remanufacturing-driven reverse supply chain. In the first phase, we propose a multicriteria/goal-programming analysis for the identification and the optimal selection of the most ‘desirable’ subassemblies and components to be disassembled for recovery, from a set of different types of EOL products. In the second phase, a multi-product, multi-period mixed-integer linear programming (MILP) model is presented, which addresses the optimization of the recovery processes, while taking into account explicitly the lead times of the disassembly and recovery processes. Moreover, a simulation-based solution approach is proposed for capturing the uncertainties in reverse logistics. The overall approach leads to an easy-to-use methodology that could support effectively middle level management decisions. Finally, the applicability of the developed methodology is illustrated by its application on a specific case study.     

Air cushioned vehicles: Efficient alternative transportation for spill response

During the first 72 h of a spill, the focus is on stabilization of the casualty and on open water recovery. As the oil moves into shallow water, technology often gives way to labor and the ensuing battle is won or lost on an efficient means of transporting a vast network of responders and their equipment. From an operations perspective, transportation alternatives can be evaluated, most simplistically, by two standards: speed and cargo capacity. How fast can resources be delivered to the site? What is the payload of the vehicle delivering the resources? As the life of the incident grows and more resources are committed to the project, the issues of delivery speed and delivery volume become more critical. The traditional means of transporting a response organization by land, air, or water always seem to leave a gap in efficiency, particularly when mounting a shoreline clean-up campaign. This paper seeks to build enthusiasm within the response community for viewing the air cushioned vehicle (ACV) as the amphibious alternative in marine spill response transportation. Theory, case histories, and personal experience are used to develop support for planning ACVs into future response roles.     

Oil Spill Modeling towards the Close of the 20th Century: Overview of the State of the Art

The state-of-the-art in oil spill modeling is summarized, focusing primarily on the years from 1990 to the present. All models seek to describe the key physical and chemical processes that transport and weather the oil on and in the sea. Current insights into the mechanisms of these processes and the availability of algorithms for describing and predicting process rates are discussed. Advances are noted in the areas of advection, spreading, evaporation, dispersion, emulsification, and interactions with ice and shorelines. Knowledge of the relationship between oil properties, and oil weathering and fate, and the development of models for the evaluation of oil spill response strategies are summarized. Specific models are used as examples where appropriate. Future directions in these and other areas are indicated     

Selection criteria for waste management processes in manned space missions

Management of waste produced during manned space exploration missions will be an important function of advanced life support systems. Waste materials can be thrown away or recovered for reuse. The first approach relies totally on external supplies to replace depleted resources while the second approach regenerates resources internally. The selection of appropriate waste management processes will be based upon criteria which include mission and hardware characteristics as well as overall system considerations. Mission characteristics discussed include destination, duration, crew size, operating environment, and transportation costs. Hardware characteristics include power, mass and volume requirements as well as suitability for a given task. Overall system considerations are essential to assure optimization for the entire mission rather than for an individual system. For example, a waste management system designed for a short trip to the Moon will probably not be the best one for an extended mission to Mars. The purpose of this paper is to develop a methodology to identify and compare viable waste management options for selection of an appropriate waste management system.     

Integration of RBCA frameworks and remediation technologies

Decisions that determine the proper risk-based remediation approach are based on technical, regulatory, cost, legal, and political factors. A wide variety of options such as the ASTM RBCA tiered approach, the API Decision Support Software, and a host of agency-specific methods and commercial risk assessment software are all available. The optimization of a remediation project requires the right remediation technology coupled with the appropriate analytical framework. For groundwater remediation, the application of various “risk reduction” technologies can be classified as aggressive (pump and treat), moderate intensity (air sparging), low intensity (oxygen release compound-ORC®), and intrinsic (monitor only). The time frame of risk analysis will establish the proper risk reduction strategy. The selection process is inherently iterative, and the approach by which an optimal solution can be derived forms the basis of this article. A case study of a Texas site put these issues into context.