Cost of Remediation
Costs of remediation technologies can be separated into two broad categories: (1) upfront costs required to complete installation of a particular treatment technology and (2) operation and maintenance (O&M) costs. Upfront costs include design, construction, and administrative costs for the installed remedy including all components that are needed for complete process operation. These costs include those to prepare documents such as the remedial design, work plan, sampling and analysis plan, and health and safety plans; to interact with regulatory agencies and acquire permits; to prepare site infrastructure including performing a site survey, locate subsurface utilities and other obstructions; to construct/procure infrastructure to supply electricity, water, and natural gas as needed; to mobilize and install the process equipment; and to perform startup and shakedown testing.
After completing installation of a treatment system and/or introducing the necessary amendments into the aquifer, O&M is conducted, and ongoing costs are incurred. Operations must be monitored, powered, inspected, repaired, and reviewed. These activities require additional capital that must be spent over the duration of the remedy until the remedy has achieved its remedial goals (RGs). Specific costs include those for monitoring the performance of the technology, performing maintenance, and collecting groundwater, soil, and/or vapor samples to monitor progress toward RGs.
For the purpose of these technology profiles it should be noted that upfront costs for those technologies that rely on the emplacement of amendments (e.g., enhanced reductive dechlorination [ERD], in situ chemical oxidation [ISCO], and in situ chemical reduction [ISCR]) include the capital necessary to introduce the amendments to the aquifer if the amendments are added during a single event over a short period (i.e., weeks or less). If amendment application is performed over an extended period (months to years), only those costs associated with equipment mobilization, installation, startup and shakedown are included as upfront costs. Additional costs are included as O&M costs. For instance, direct injection of emulsified vegetable oil (EVO) into 40 direct push technology locations over a 2-week period is considered an upfront cost. However, performing these injections once per month over a 12-month period or introducing EVO over a 6-month period using a recirculation system would be considered O&M costs. Only those costs associated with the first injection or startup/shakedown of the recirculation system would be considered upfront costs.
Each profile provides technology-specific upfront and O&M costs. The profiles highlight those cost dependencies specific to the technology described and do not consider the dependencies that are general to most in situ remediation technologies. A description of various costs is provided below. Project-specific cost estimates should be developed considering the information provided in the technology profile along with the additional information presented below and should be developed using an integrated cost-estimating application such as RACER® or consulting with a subject matter expert.
Investigation and Design Costs
Before designing and implementing a treatment remedy, a conceptual site model (CSM) must be developed to the extent necessary to establish appropriate design criteria. Locating the contaminant source mass and characterizing site heterogeneity is paramount to the design phase. Some technologies, such as in situ barriers, require less knowledge of the exact location of contamination than others, such as highly targeted amendment delivery using hydraulic fracturing. Site data are reviewed and data gaps are identified, and then additional characterization is conducted as necessary leveraging existing monitoring infrastructure when possible. Variables that impact pre-design costs include the resolution of the CSM required by the technology, the breadth of the existing dataset, the extent of existing infrastructure that can be used (e.g., a monitoring well network that simply needs to be sampled for additional analytes versus an uncharacterized site), the complexity of the site and its lithology, and the types/diversity of contaminants of concern (COCs).
Traditional techniques to develop a CSM can include sampling a previously installed monitoring well network, grab sampling, or installing additional monitoring wells or soil vapor probes. Often the resolution of site characterization is a significant factor of the pre-design phase costs. Many times, mobile laboratory or field detection techniques are used to iteratively develop a real-time understanding of the site. These techniques help develop a high-resolution CSM with minimal increase in overall lifecycle cost. Increasing effort in the pre-design phase often has the effect of reducing overall costs associated with remediation technologies, by either reducing risks associated with uncertainty (e.g., costs due to remedy failure) or by trimming excess treatment volume.
Design phase costs vary depending on the size and complexity of the site and the remedy, novelty of the remedy, and degree of monitoring and instrumentation. For example, the design of an experimental groundwater extraction and treatment train with a high level of instrumentation might cost more than simple excavation and off-site disposal.
During all phases of the remedial process, there exists a risk of failure and the event that a contingency strategy must be implemented, which increases cost (e.g., having to perform an additional unexpected injection event due to stalled groundwater concentrations). There is a trade-off between risk of failure and increased investment in upfront costs. Decision-making techniques have been developed that compare cumulative probability of success with total cost, which is useful for comparing the lifecycle cost of various remedy pathways. Remedial alternatives with greater upfront costs that offer high probabilities of success are more likely to be cheaper over their lifecycle than a risky, low-cost alternative that can lead to a runaway budget.
Bench-and Pilot-Scale Tests
Bench-scale treatability studies and pilot tests also factor into design costs. Unless data are available through previous investigations, bench tests to determine design factors such as reaction chemistry, sorption properties and other chemical, physical and biological parameters, can be performed in the laboratory. Bench-scale testing is particularly important to estimate mass of reagents that will be required for various in situ technologies such as in situ chemical oxidation (ISCO) and enhanced reductive dechlorination (ERD).
Pilot tests generally are performed in a small area of the site and are useful for measuring radius of influence and the impact that site-specific aquifer properties will have on a particular technology. In some cases, a technology may be relatively new and/or substantial design data may not be available to treat a particular (emerging) contaminant and therefore a pilot test is recommended to provide additional data to design a full-scale system.
Costs associated with bench- or pilot-scale tests depend heavily on variables such as the coverage of existing site data and the complexity of the site and its lithology. However, increased investment in the design phase often decreases overall costs associated with the remedy. Bench- and pilot-scale testing is technology specific and is further discussed in each profile as applicable.
Regulatory Program/Oversight and Document Preparation
Remedial actions may be performed under various regulations such as Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Resource conservation and Recovery Act (RCRA) and cleanup programs such as the Defense Environmental Restoration Program (DERP), State-led underground storage tank (UST) programs, Brownfields, voluntary cleanup programs, and others. Each of these has various requirements related to the types of documents that are prepared and how information is communicated with the public. These requirements are not trivial and can significantly impact the cost of a restoration project. Many times, multiple versions of design documents including remedial designs, remedial action work plans, remedial alternative analyses, and sampling and analysis plans may be required to allow stakeholder review and buy in. CERCLA and DERP require a high degree of community involvement for most remedial actions. Restoration Advisory Board meetings attended by the public, proposed plans, and fact sheets are generally required and can substantially increase upfront costs.
Costs for any necessary permits also must be considered and included in the budget. Oftentimes permits are required to install and abandon wells, inject fluids, install utility infrastructure, and excavate soils. The United States Environmental Protection Agency (U.S. EPA) waives the requirement to obtain a permit and associated administrative and procedural requirements of permits for on-site CERCLA response actions. However, all activities must comply with the substantive provisions of the permitting regulations.
Construction and Startup Costs
Construction-phase activities typically include mobilization and site preparation; equipment procurement, construction, and installation; monitoring network installation; and startup and shakedown. A description of associated costs for these activities is included below.
Labor is required for every element of the installation and startup of the remedial system. Cost dependencies for labor include prevailing wage rates, the size and complexity of the site and associated treatment equipment, and site-specific infrastructure and conditions (e.g., presence of buildings, active parking lot), which can increase time and cost to install and secure equipment and associated distribution piping. Specialized training may be required to perform various site-related activities (e.g., Hazardous Waste Operations and Emergency Response, confined space, and first aid), which may affect the prevailing wage rates.
Equipment and Specialized Services Procurement — Equipment must be procured in accordance with contract requirements. In addition, services such as drilling, electricians, utility locating, heavy equipment operators, welders, and others may be required. Solicitation of multiple bids for equipment and services is recommended to ensure a fair and reasonable price. The level of effort required for these activities is dependent on the complexity of the remedy. For instance, procurement activities associated with the installation of a permanent pump-and-treat system that is expected to operate one or more decades and will be housed in its own building will require substantial more level of effort compared to installation of a trailer-mounted multi-phase extraction system.
Site Preparation — Preparation consists of locating subsurface utilities; supplying power, potable water, or any other utility to the site; securing the site with temporary fencing or other means as necessary. These activities are site-specific and vary depending on site conditions and infrastructure. For example, it might be costly to provide roads, utilities, and a temporary workspace to the example site on a remote Aleutian Island, but excess costs of securing the site with fencing and providing traffic detours might also be avoided.
Mobilization — All necessary equipment and personnel must be transported to the site. Cost considerations include site location, access, duration of the construction phase, and the complexity and quantity of materials and equipment. Mobilization to remote, difficult-to-access sites (e.g., a remote Aleutian Island) has higher associated costs. Construction duration has a complicated cost-dependency; costs increase as the duration of the construction phase increases up until a point when construction would be less expensive because semi-permanent or local residents could be hired to staff the project. Complex or sensitive equipment or materials also will increase mobilization costs. Staff are often required to coordinate and receive the mobilized equipment at the site, which is another cost factor for mobilization.
Construction and Installation — Manpower, tools, and expendable materials are necessary to complete the installation of the remedy. Costs are dependent on the degree of complexity and instrumentation along with the novelty of the technology. For instance, custom-designed and hand-assembled treatment systems are much more expensive to procure and install on site than a commercially-available trailer-mounted unit. The extent of subsurface features (e.g., wells and piping), investigation derived waste (IDW) disposal requirements, and the scale of the project all impact costs.
Monitoring Requirements — Process and performance monitoring are required to ensure that the technology is operating according to design and gauge its progress toward achieving RGs Although costs for monitoring itself is an element of O&M costs, a performance monitoring network typically is required and installed during construction of the remedy. Monitoring costs are technology-specific and can consist of anything from instrumentation such as in situ thermocouples or stack emissions monitoring devices to groundwater wells. Costs can be minimized by leveraging existing site infrastructure when possible. Costs also are highly dependent on regulatory requirements, the complexity and novelty of the technology, and the areal extent of contamination.
Operation and Maintenance Costs
Process and Performance Monitoring
Monitoring includes a wide array of tasks associated with evaluating successful operation of a remediation technology. These tasks are technology-specific, but typically cover two broad areas: (1) monitoring parameters associated with the technology itself (process monitoring), and (2) monitoring the remediation progress in the context of remedial action goals, such as measuring changes in concentrations in the impacted media (performance monitoring). These profiles do not consider monitoring and associated costs beyond what is required to implement and monitor a specific technology.
Process Monitoring — Information pertaining to the operation of the remedy must be collected from sources such as data loggers, gauges, sampling ports, down-hole probes, or other operational measurements. Activities and associated costs are technology-specific. Complex systems (such as components of groundwater extraction and treatment plants) often have both programmable logic controllers (PLCs) and/or proportional-integral-derivative (PID) controllers that operate collectively with a supervisory control and data acquisition (SCADA) system that uses networked data communications and graphical user interfaces for high-level management tasks. If so equipped, monitoring generally is conducted remotely with occasional routine visits for collecting operational data during O&M activities. For less complex systems and technologies, performance monitoring can be as simple as keeping a yearly record of visual observations and manual entry of various key data. For instance, photos, measurements of height and width of plants, and moisture content in soil may suffice for a phytoremediation application. Costs associated with process monitoring often can be correlated to the number of labor hours required for data collection. Labor cost dependencies include prevailing wage rates, the size of the site, and complexity of the treatment equipment. Site-specific requirements for site access and personal protective equipment and decontamination also can impact costs.
Performance Monitoring — Collecting groundwater, soil and/or vapor samples for analysis and comparing the results to those from a baseline sampling event conducted prior to remedial operation. General cost dependencies include the areal extent of contamination, complexity of the remedial action, sampling frequency, and analytical and regulatory requirements. Performance monitoring costs are highly dependent on the number of samples collected, types of media sampled, analyses performed, and nature and volume of IDW requiring disposal. Larger sites, at which multiple media (e.g., soil and groundwater) are monitored, with a wide-range of contaminants will have much greater performance monitoring costs than smaller sites at which few contaminants are monitored in a single media.
Utilities, Raw Materials, and Waste Products
Operation of the remediation technology often requires utilities such as electricity, natural gas, fuel, water, or telecommunications as well as raw materials such as chemical amendments, sorbent materials, and a wide range of other consumable materials. Many technologies require the disposal of waste, be it from spent granular activated carbon or filter cake to phytoaccumulation plant matter harvested for off-site disposal or soil cuttings from sampling activities. Cost dependencies include power requirements, which are a function of the size and complexity of the treatment technology and the site, and utility and material unit rates, which are a function of the location of the site. Costs for materials can often be reduced by using local and recycled or repurposed materials (e.g., used frying oil as an ERD amendment substrate).
Operation of a remediation technology often requires routine and non-routine maintenance. The intent of maintenance is to reduce operational downtime and the depreciation of fixed capital and to increase the effectiveness of the remedy. Maintenance is technology-specific and can involve a wide range of activities such as repair of physical equipment or performance, descaling of wells and pipes, reinjection of amendments or the irrigation of a phytoremediation site among many others. Typically, increasing the duration and complexity of the remedy intensifies the prescription of maintenance activities, which increases cost. Much like performance monitoring, costs with this task can often be correlated to the quantity of hands-on labor hours required for maintenance activities.