H 1.1 Using Bottom Ash Dewatering Systems to Treat Outage Wash Wastewater
H1.1 Lessons Learned from Using Bottom Ash Dewatering Systems to Treat Outage Wash Wastewater
David Donkin – UCC Environmental
The coal-fired electrical utility sector is faced with the regulatory requirement to retire their coal ash sluicing ponds under the finalized Coal Combustion Residuals (CCR) regulation in the Spring of 2021. Wet-to-dry ash handling solutions are being implemented throughout the fleet to allow ponds to come out of service. However, the final disposition of outage wash wastewater, specifically the wastewater generated from washing boiler internals, air pre-heater, economizer and precipitator systems must also be considered. Historically these washwaters were simply directed to the CCR pond along with other ash materials and treated by dilution and settling prior to discharge. This option is longer available. The primary constituents of concern are total suspended solids, iron, copper and other heavy metals, and pH control. In addition, outage wash wastewater presents unique challenges with respect to wide flow variations and contaminant loading changes throughout a wash. A temporary or permanent retro-fit of existing wet-to-dry bottom ash handling systems can allow these systems to serve as a wastewater treatment system in order to meet water quality requirements with respect to outage wash wastewater streams. UCC Environmental’s lessons learned from over 2 years providing these retrofits and treating wastewater from outage washes will be reviewed.
H 1.2 Engineered Soil Cover Systems for Sustainable CCR Closures
H1.2 Engineered Soil Cover Systems for Sustainable CCR Closures
Marc Theisen – Profile Products LLC
Design and construction of cost-effective cover systems are critical to successful CCR closure projects. Traditional cover system designs involve placement of highly specialized barrier and drainage systems capped with 12-18” of cover soils, then topped with 4-8” of a “vegetative soil layer”. On large closure projects the costs of procurement, transportation and placement of suitable topsoil can be exorbitant. Emerging topsoil alternatives such as Engineered Soil Media can make even marginal soils suitable for vegetative establishment while offering significant cost savings. Vegetation is the most sustainable consideration for CCR closures, providing immeasurable environmental benefits as expounded in this presentation.
H 1.3 Community Air Monitoring During Demolition and Management for Environmental Justice
H1.3 Community Air Monitoring During Demolition and Management for Environmental Justice
Melissa McLaughlin – AECOM
AECOM has been designing, installing and operating perimeter ambient air quality and meteorological programs for over 40 years. AECOM’s more recent experience includes numerous perimeter monitoring programs around hazardous waste sites, landfill excavation projects, former MGP site remediation projects, and dredging and sediment processing projects. The same guidelines and approaches apply to dust generated during demolition projects, especially for power plants that have known metals, asbestos, PCB, and crystalline silica impacted building materials. This presentation will focus on the past, present and future of fenceline air monitoring and how environmental justice is creating change.
H 1.4 Decommissioning & Demolition for Power Plants
H1.4 Planning and Implementation of Decommissioning & Demolition for Power Plants
Jeff Pope – Burns McDonnell
With the impending closure of fossil fuel-fired power plants around the country due to cheaper natural gas and environmental regulations, utilities are planning for decommissioning & demolition (D&D) of these plants. The D&D process presents a unique challenge to utilities to conduct the work safely, minimizing cost and concluding with a potentially reusable site.
Planning and implementation of the D&D of these facilities requires upfront planning and coordination with utilities’ operations, environmental, security, safety, management and other stakeholders to successfully complete the project. Upfront identification of permitting issues involving waste disposal, working within a floodplain, demolition permitting, asbestos abatement and isolation of common services at the plant prior to demolition is imperative to manage project expectations and minimize change orders due to technical requirements of any required permits.
This presentation provides a description of some of the key items required to plan and implement D&D process. Several recent project examples will be summarized identifying the actual activities undertaken and the resulting lessons learned.
H 1.6 Safety Considerations for Plant Decommissioning & Demolition
H4.4 Safety Considerations for Plant Decommissioning & Demolition
Jeff Pope – Burns & McDonnell
The demolition of a power plant presents a unique challenge to utilities. It is important to understand the steps involved in order to conduct abatement and demolition work safely. Demolition of a power plant is different from constructing a new facility in that the dropping and removal of equipment can be unpredictable, therefore safe and controlled methods must be employed. Proper planning is necessary to implement demolition for these plants so that the work can be conducted safely, reduce overall cost and the utility will have a clean, reusable site.
This presentation provides a description of some of the key items required to safely plan and implement a successful demolition project. Different types of demolition methods will be described along with several steps to be considered to plan a safe project.
Co-Author: Donald Barris, III, Burns and McDonnell Engineering Co., Inc.
H 2.1 Risk Assessment at Coal Combustion Product Sites for Remedy Selection and Public Communication
H2.1 Risk Assessment at Coal Combustion Product Sites for Remedy Selection and Public Communication
Ari Lewis – Gradient
The 2015 federal coal combustion products (CCPs) Rule does not include a specific provision for the use of risk assessment at CCP storage sites. However, issues related to remedy selction and potential future revisions to the CCP Rule raise the possibility of using risk assessment to support various closure-related activities, including remedy selection and implemenation, alternate liner demonstrations, and risk communication. In the absence of specific guidance from the federal government risk assessors will need to consider relevant state guidance, constituents of interest, populations of interest, exposure assumptions, and the appropriate use(s) of measured and modeled environmental data.
H 2.2 Beneficiation of CCPs through CO2 Uptake & Mineralization
H2.2 Beneficiation of CCPs through CO2 Uptake & Mineralization
Tiffany Duffy – Carbon Upcycling
This presentation will introduce the CCP beneficiation process developed by Carbon Upcycling Technology. The technology utilizes the CO2 from a power plant’s flue gas stream and CCP waste streams to improve the performance and marketability of low-quality materials. Information will include an explanation of the technology, real-world applications, and verified performance as a solution to recycle and reuse CCP waste streams.
H 2.3 Considerations for the Successful Pond Closure and Water Treatment Under Today’s CCR Rule
H2.3 Considerations for the Successful Pond Closure and Water Treatment Under Today's CCR Rule
Jack Ma – UCC Environmental
This paper discusses the key considerations for the coal combustion residuals (CCR) pond closure and impoundment water treatment. In the development of CCR rule, the EPA’s technical evaluation concluded that closure-in-place and closure-by-removal of coal ash ponds were the best options to protect our environment for generations to come. It is worth noting that the common denominator of closure-in-place and closure-by-removal is the dewatering process and water treatment. The development of cost-effective technologies to treat ash pond water and reliably remove arsenic, selenium and mercury from water have been prioritized by coal fired power industry as environmental standards are currently very low in North America with a potential to be even lower. In addition to provide insights on various physical and chemical technologies for ash pond water treatment, this paper highlights the lessons learned from one full-scale case study with arsenic as one of the primary treatment goals. The full-scale treatment process was configured as a robust system consisting of flow and constituent equalization, multi-chemical injection for the pH control and particulate coagulation, staged filtration for the solids separation, and activated media adsorption of dissolved arsenic. The development of project specific treatment technologies should be prioritized to ensure full compliance with regulatory limits while minimizing the costs attributed to ash handling and water treatment.
H 2.4 Insurance Coverage for CCR Investigation and Remediation
H2.4 Insurance Coverage for CCR Investigation and Remediation Costs
John Hagan and Mike Lynch – K&L Gates
Insurance policies may provide utilities with significant funding for CCR-related investigation and remediation costs. In particular, a utility’s historical liability policies purchased decades ago may pay for the property damage (including contamination of soil and groundwater) that has occurred. Our presentation will identify key issues relating to insurance recovery for CCRs, answer common questions, and offer tips from our decades of experience helping utilities secure coverage for environmental claims.
H 2.4 Utility Operations and Managing Environmental Risk
H4.1 Utility Operations and Managing Environmental Risk
Nick Steinke – Olsson
Utility environmental managers face an increasingly complex and changing landscape of risks and requirements while having limited resources available to effectively manage their responsibilities. A formal environmental management system (EMS) approach can help the organization to: identify, prioritize, and reduce risks; improve compliance with environmental requirements; encourage stakeholder engagement; and support the overall sustainability of the organization. This presentation will include: an overview of ISO 14001 for EMS; the benefits of a management system approach, including the use of audits to manage risks; implementation strategies and challenges; information management strategies; and an application of this approach at a Utility (pending confirmation).
H 3.1 Beneficiation of Harvested Fly Ash Using a Triboelectric Belt Separator
H3.1 Beneficiation of Harvested Fly Ash Using a Triboelectric Belt Separator
Kyle Flynn – Separation Technologies
Tribo-electrostatic separation has been used for the commercial beneficiation of coal combustion fly ash to produce a low carbon product for use as a cement replacement in concrete for twenty-five years. With 24 separators in 18 coal-fired power plants and cement plants across the world, Separation Technologies’ (ST) patented electrostatic separator has been used to produce over 20 Million tons of low carbon product that has been recycled for use in concrete or cement production.
To date, commercial tribo-electrostatic beneficiation of fly ash has been performed primarily on dry “fresh” or “production” ash. Reductions in the quantity of dry fly ash generated and requirements to empty historical ash landfills and ponds has created the need to develop a process to reclaim and beneficiate landfilled or ponded ash.
ST has developed and commercialized a new process for beneficiation of reclaimed fly ash from landfills and ponds that utilizes fly ash drying and deagglomeration technology together with the ST tribo-electrostatic carbon separation technology. ST has installed a demonstration of this new process at the Talen Energy Brunner Island power station near York PA. The ST fly ash beneficiation process offers both utility and cementitious materials customers an environmentally friendly, low-carbon emission, fly ash recycling technology which enables cost effective landfill and pond reclamation.
H 3.2 Coal Ash and Politics: Two Things That Aren’t Polite to Discuss at the Dinner Table
H3.2 Coal Ash and Politics: Two Things That Aren’t Polite to Discuss at the Dinner Table
John Ward – John Ward Inc
Implementation of the U.S. Environmental Protection Agency’s 2015 regulation for coal combustion residuals disposal is well under way, but that hardly means the science is settled. Several additional CCR related rulemakings remain open at EPA and recent actions by the Agency interpreting aspects of the 2015 rule have created uncertainty and attracted litigation. This presentation will summarize the current regulatory state of play and discuss potential future impacts of political shifts in Congress, the presidency, and U.S. Supreme Court.
H 3.3 Cost-effective, Green, Concrete Domes for Bulk Storage of CCPs
H3.3 Cost-effective, Green, Concrete Domes for Bulk Storage of CCPs
Michael Hunter, CEO – Domtec International, LLC
This paper focuses on optimizing bulk storage of Coal Combustion Products (CCPs). It discusses state-of-the-art, green (climate friendly), storage structure solutions for plants, terminals and ports using concrete domes in both domestic (USA) and overseas markets.
Various successful storage projects will be discussed including for fly ash, limestone, coal, and FGD gypsum. The benefits of dome storage will be addressed as well as various methods for product handling and reclaim, including automated reclaim systems mechanical and pneumatic (screws, stacker-reclaimers, and fluidized floors, etc.).
The paper will also demonstrate how concrete domes are truly a ‘green’ storage structure alternative.
3 short Questions
How are concrete domes a more efficient type of storage structure?
In what ways are concrete domes considered ‘green’?
H 3.4 Six Years of Service, Supply, and Success: Processing Harvested CCR from Impoundments
H3.4 Six Years of Service, Supply, and Success: Processing Harvested CCR from Impoundments
Bill Fedorka – The Sefa Group
The positive economic and technical benefits of utilizing fly ash as a replacement for cement in concrete has an extensive and successful history. However, the availability of fly ash for use as a supplementary cementitious material (SCM) in concrete has decreased dramatically. Harvested CCR from legacy disposal and storage sites has proven to be a valued source of material.
The SEFA Group began testing the use of harvested CCR as a replacement for production fly ash in 2012. In 2014, SEFA decommissioned its CBO Plant at Santee Cooper’s Winyah Station and constructed a STAR® facility designed to operate with 100% reclaimed fly ash as its primary raw feed source.
Since commercial operation in 2015, nearly two million tons of CCR from onsite ash impoundments has been reclaimed and processed at the Winyah STAR® Plant. It has consistently produced a product ash below 1.0% loss on ignition (LOI), while meeting all relevant specifications for use in ready mix concrete as a replacement for Portland cement.
In late 2020, and early 2021, SEFA commissioned three (3) new STAR Facilities in North Carolina that use 100% reclaimed CCR as raw feed. Combined, these facilities are capable of processing upwards of 1.5 million tons per year of legacy CCR. Since coming online, nearly 1 million tons of coal ash have been permanently removed from the environment and recycled for encapsulated use in the concrete products market.
H4.5 Understanding IPB Requirements for Transformer Change-Outs
Mohsen Tarassoly – Electrical Builder, Inc.
The purpose of this presentation is to provide a brief overview of a transformer replacement project requirements and critical paths. A key element in the generation system, transformers require regularly scheduled maintenance and upkeep. The requirement for replacement of transformers is rather common and consistent; stemming from the need for system uprate, age of the equipment, use of newer technologies, and transformer issues caused by lack of and/or poor maintenance. While much time is spent on analyzing the transformer exchange, often times, a critical factor that is often overlooked is the impact the exchange will have on the existing bus duct system. A variance in elevation, flange layout, orientation of contact surfaces, and phase spacing, are just a few obstacles that could easily cause major delays if not foreseen and properly planned for. The presentation highlights the process to initiate the transformer replacement process, where applicable (system uprate), the sequence by which such projects are carried out, and the pitfalls to avoid that can greatly impact the project’s schedule.
H 4.4 Taking on the Challenge of Ponded Ash Benefication & Generating Cementitious Fly Ash
H5.4 Taking on the Challenge of Ponded Ash Beneficiation & Generating Cementitious Fly Ash
Chris Poling – Ash-TEK
There are several technical challenges that must be overcome to beneficiate landfilled and ponded coal ash. These ashes undergo a series of chemical and physical changes which makes recovering them for beneficial re-use a challenge. After years of exposure to the elements many of the alkalis have dissolved and then re-deposited themselves as oxidation on the surface of the particle. The overall reactivity of the ash has been significantly reduced due to the high moisture content of the storage pond or landfill. The original qualities which prevented the ash from being used in concrete still exist in terms of ammonia, sulfur and/or high LOI or other contaminants.
The PABS offered by Ash-TEK and supported by LafargeHolcim delivers a consistently high quality ash which has repeatedly demonstrated improved performance above and beyond that of freshly generated ash in terms of strength, workability and water demand. The benefits include:
– elimination of groundwater contamination
– increased property values
– lower cost cementitious material
– contribution to the circular economy
– increased local employment
– Reduced GHG emissions compared to Portland Cement
The system is portable, patent pending, simple, and will be commencing industrial operation in 2023.
H 4.1 CCR Supply Today and Tomorrow – Closing the Gap Between Supply and Demand
H5.1 CCR Supply Today and Tomorrow - Closing the Gap Between Supply and Demand
Thomas Adams – ACAA
Demand for supplementary cementitious materials (SCMs), especially fly ash, has increased sharply over the past decade, outpacing supply in some regions of the country. This trend is expected to continue as durability expectations for concrete pavements and structures rise. With coal-fueled generation at about 20% of total generation, how will the gap between supply and demand be addressed? Several market developments hold great promise in meeting this challenge. Harvesting coal ash from disposal units for processing to concrete-grade quality is in its infancy. The blending of various types of fly ash and bottom ash is a reality in some markets. Blends of fly ash and natural pozzolans are finding commercial acceptance. Revisions to the specifications of ASTM International and the American Association of State Highway and Transportation Officials are under consideration. Other supplementary cementitious materials such as slag cement and natural pozzolans are filling some of the demand, but their combined volume available to the market is less than half of the fly ash supply. Importing is often mentioned as a part of the supply solution, but the costs and logistical challenges have kept imports to a minimal level. This presentation will discuss these solutions to meeting market demand over the coming decades.
H 4.2 Making ash harvesting pay, the low energy route
H5.2 Making ash harvesting pay, the low energy route
Richard Atkinson – Coomtech Ltd
Drying ponded ash is one of the most energy-intensive steps in beneficiation. For both cost and resource availability reasons, getting the energy budget down is a key step in economic harvesting.
Coomtech’s Kinetic Dryer cuts out the main cause of dryer energy consumption: boiling off the water. By replacing thermal drying with a turbulent air process that shears the water off the surface, Kinetic Drying can bring the drying energy budget down by 75%.
Richard will explain how the technology works, when it can be the right technology solution, and how it can be tailored to your ash harvesting situation.
3 short Questions:
Can you make use of low-grade waste heat?
What is the plant footprint?
What are the costs and capacity levels?
H 4.3 In-Situ Stabilization for Hydraulic Control at CCR Sites
H5.3 In-Situ Stabilization for Hydraulic Control at CCR Sites
Paul Lear – Forgen
Hydraulic containment involves controlling the movement of contaminated groundwater, preventing the continued expansion of the contaminated zone. CCR impoundments and landfills with impacts to groundwater can benefit from hydraulic containment.
Traditionally, slurry walls have been used for hydraulic containment. The installation of slurry walls require large work platforms adjacent to the trench and has stability issues when working along toe slopes. In-situ Stabilization (ISS) is an applicable technique for the installation of diaphragm walls for hydraulic containment. Producing a continuous wall in place by ISS eliminates the need for excavation and support of a trench under slurry and for a large work platform to prepare the trench backfill. ISS reduces the amount of reagents required and eliminates the need for a slurry-supported trench.
A overview of hydraulic control and ISS techniques will be given to familiarize the audience with these technologies. An example project where ISS was utilized to establish a one mile long, vertical, low permeability hydraulic control around a site containing two former landfills and adjacent to riverine wetlands, to prevent contaminated groundwater from entering a nearby river will be discussed to demonstrate the applicability of this technique.
H 4.5 COAL ASH HARVESTING FOR BENEFICIAL REUSE – CHALLENGES AND LESSONS LEARNED
H5.5 COAL ASH HARVESTING FOR BENEFICIAL REUSE – CHALLENGES AND LESSONS LEARNED
Tom Kierspe, P.E.
Issues and options to close and clean up legacy ash ponds can generate a great deal of attention from neighbors and local community organizations, environmental advocacy groups, ratepayers, economic development agencies, and ash users. Fortunately, the knowledge base for harvesting and beneficiation of CCP impoundments has continued to increase and thereby removed much of the uncertainty about the technical capability to beneficially reuse the CCP material. Now, based on years of commercial operating experience, there are many lessons learned surrounding characterization and management of the stored CCPs, harvesting practices, and other considerations that, taken into consideration, can serve to increase the likelihood of a positive outcome for all stakeholders. Minimizing overall cost, optimizing removal timeframes, and operational efficiencies for closure are just some of the factors that can be positively influenced by drawing on actual experience.
In this presentation, the challenges and lessons learned from active reclamation and beneficiation projects will be reviewed, as well as the potential benefits from incorporating this knowledge into future projects.
The SEFA Group, 219 Cedar Road, Lexington, SC 29073
H 3.6v Geochemical Changes at CCP Sites in Response to Mitigative Actions (Virtual)
H3.5V Evaluation of Long-Term Geochemical Changes at CCP Sites in Response to Mitigative Actions
PJ Nolan – WSP Golder
Power utilities worldwide are challenged by regulatory agencies to implement remediation strategies that anticipate long-term changes to groundwater quality in response to closure activities. In many cases, unanticipated changes to site geochemistry due to closure can have unforeseen impacts. Sometimes, the remediation efforts used can even initiate the re-mobilization of the original constituents, causing the site to be contaminated again. In this paper, we demonstrate how geochemical modeling can be used to evaluate the long-term stability of COIs in the subsurface, including the time required to meet compliance standards, providing a valuable decision-making tool for stakeholders.