Abstract
Applying environmental sustainability concepts to contaminant remediation continues to evolve in the remediation cleanup marketplace. Increasingly, we recognize that mass transfer remediation practices only defer contamination problems to the future. The importance of environmental footprints in remediation work related to global issues has led to the consideration and development of sustainable practices in the selection and design of remediation systems. The recent development of Remediation Carbon Footprint Models (RCFMs) globally illustrate a variety of approaches to estimating the carbon footprints of remediation activities, ranging from simple, user-friendly input to comprehensive inputs resulting in cradle-to-grave considerations of carbon footprint impacts. Preferred practices in environmental sustainability increasingly contribute to long-term protection of human health and the environment, conservation of natural resources, and biodiversity – all balanced against economic viability. Sustainable remediation seeks to connect and balance shared values between economics, environmental, and social contributions.
Introduction
In the past few years, carbon footprint estimating tools have been developed for varied uses ranging from personal or household applications created by worldwide private, educational, and government sources. Examples of household on-line calculators for estimating individual carbon emissions include Cool Climate (UC Berkeley, 2010) and USEPA's Household Emissions Calculator (USEPA, 2009).
Another example of a carbon footprint calculator is Carbon Footprint (Carbon Footprint Ltd, 2010) efforts to quantify individual carbon emissions as well as small to large organization carbon emissions. Extending the carbon footprint calculation even further, University of California-Berkeley became the first United States university to calculate its supply chain carbon footprint (University of California-Berkeley, 2007).
SimaPro (PRé, 2009) is an example of a robust Life Cycle Assessment (LCA) model, first released in 1990, that analyzes complex life cycles of materials, products, and activities in a systematic and transparent way, following the ISO 14040 series recommendations. SimaPro comes inclusive of several inventory databases with thousands of processes. SimaPro is primarily used for the assessment of products, processes and services.
These models have led the development of specific RCFMs that span the knowledge and expertise of varied users who provide the site-specific inputs for carbon footprint analyses.
Principle Factors of Impact for Sustainable Remediation
The Remediation Carbon Footprint Model (RCFM) approaches simulate and evaluate sustainability in the application of technologies during selection, design, execution, and optimization phases of remediation work. Global as well as local considerations in carbon emissions have been implemented into most RCFM approaches for remediation technology processes. One primary factor, the user, dictates the depth of knowledge and expertise required to properly input data and information into any of these models. Other desired RCFM outputs, such as site-by-site comparison, technology comparisons, and cost comparisons, are focused differently for the various modeling approaches.
HMVT's Carbon Footprint Model (HMVT, 2008) illustrates an early RCFM adaptation of carbon emission calculations into remediation elements consisting of materials, transportation, energy, remedial approaches, and waste disposal.
A further advancement in RCFM estimating is the Sustainable Remediation Tool (SRT). The SRT development (AFCEE, 2009) served two general purposes: 1) planning for future implementation of remediation technologies at a particular site, as well as, 2) a means to evaluate optimization of remediation technology systems already in place or to compare remediation approaches based on sustainability metrics.
Last, the USEPA's development of the LUST Cleanup Footprint Calculator (the LUST Calculator) is a tool used to quantify the carbon footprint of leaking underground storage tank (LUST) remediation sites. The LUST Calculator (USEPA, 2010) provides initial default values as inputs, as well as allowing user-selected custom inputs, based upon surveyed baseline data for generating site-specific carbon emissions estimations. Remediation technology environmental impacts are generated for three output metrics: green house gas emissions, energy, and water usage.
All of these RCFMs allow users to estimate sustainability metrics for specific technologies.
The remaining focus of this paper is to inspect and compare inputs and outputs of two RCFM approaches: HMVT's Carbon Footprint Model and the U.S. EPA LUST Calculator.
Presentation of Data and Results
HMVT Carbon Footprint Model
HMVT's Carbon Footprint Model (CFM) collects site remediation data, convert data into equivalent CO2 emissions, and evaluate CO2 emissions in a comparative fashion. The CFM's goal is to create a model to compare different types of remedial alternatives with each other and understand each alternative's carbon footprint.
Beyond the compiled carbon emissions data outputs, the CFM seeks to reduce CO2 emissions even further using a ‘green sheet’ of remediation options utilizing heat pumps, solar panels, and recycling options during clean-up operations.
HMVT's CFM is based on calculating nearly all of the emissions of carbon dioxide (CO2) to estimate a relatively quick and clean overview of the potential total CO2 emissions. The CFM displays the total emissions of CO2 resulting from consumption of electricity, water, natural gas, chemicals, and petroleum fuels for yellow iron equipment and transportation. Soil treatment options (biological, thermal, physical/chemical) and other remediation materials (granular activated carbon and HDPE piping used) are also evaluated.
Inputs are saved by the user as individual carbon footprint computer files for site-to-site comparisons to other combinations of inputs.
Comparisons for the remediation estimation of carbon emissions are through numerical inputs, comparison to matching household annual emissions, and graphical outputs of the relation between CO2-sources.
US-EPA LUST Cleanup Footprint Calculator
Another recent user-friendly RCFM is the US-EPA's LUST Cleanup Footprint Calculator (the LUST Calculator). The the LUST Calculator was created in 2010 as a tool used to quantify the carbon footprint of Leaking Underground Storage Tank (LUST) remediation sites. The Calculator evaluates remediation technologies with user-selected baseline inputs into the Calculator tool.
Remediation technology environmental carbon footprint impacts are generated for three output metrics:
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Green House Gas (GHG) emissions
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Energy Usage
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Water Usage.
The LUST Calculator allows for site-specific consideration and inputs for general Site Assessment (i.e. Site Investigation) work as well as for inputs related to implementing five remediation technologies.
These technologies are:
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Monitored Natural Attenuation (MNA)
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Soil Excavation (Excavation)
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Soil Vapor Extraction (SVE)
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Pump and Treat of Ground Water (P&T)
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Multi-Phase Extraction of Fluids and Air (MPE)
The LUST Calculator provides a user-friendly input environment to initially establish representative input values, typically median data inputs. Selecting from Baseline Ranges is accomplished with drop-down menus for additional input range choices. Pop-up windows illustrate baseline data and statistical evaluations of the peer-reviewed input data and ranges. The user can input a Custom Response when more precise input data are desired or known. Multiple technologies can be quickly evaluated for one site in 15 to 30 minutes of user-input time.
Initial LUST Calculator use defaults to values typical of relative site complexities (i.e. low, medium, high) as starting points. The user can accept or modify any of the default inputs with input range selections or custom input values that are site-specific to the LUST project. Default inputs have been vetted based upon surveys of actual site remediation scenarios by remediation practitioners experienced in implementing corrective action at thousands of LUST remediation sites.
LUST Calculator Variables, Units, Output Values, Calculations, and Reference Equation data
LUST Calculator Variables, Units, Output Values, Calculations, and Reference Equation data
Transparency in the input to output results is provided by instantaneous Output values, listing of the variable and units used, and the Calculation using the units. All variables and calculations as well as Assumptions have detailed references accessible in various data sheets.
Easy to understand output data and graphics provide objective CO2 equivalent emissions comparisons of the remediation technologies.
Conclusions
The presented Remediation Carbon Footprint Models (RCFMs) note differing user-input flexibility and input details adapted to user and site-specific knowledge and information. These RCFM tools allow multiple technologies to be quickly assessed and compared for one site's respective carbon emissions. Visualizations of the output carbon emissions serve to quickly illustrate greener cleanup options for specific work activities or major emission sources during the execution of remediation projects. Inputs that have the largest impact on GHG emissions are highlighted. All equations and assumptions are transparent for all calculations in the LUST Calculator.
This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.
Acknowledgment
Eric Magnan, USEPA-Region 9, provided project management of the EPA LUST Calculator development, and his project contributions are gratefully acknowledged. The views and opinions expressed in this paper represent only the Antea Group authors. The views or policies of the USEPA are not represented in this paper.
