Dave Cook Delves into Ecology’s Affordable Housing Cleanup Grant Program at MTCA Law Seminar

Senior Principal Geologist Dave Cook, LG, CPG, will be a part of a seminar on Thursday, December 7 focused on the Model Toxics Control Act (MTCA). First adopted by the Washington State Department of Ecology (Ecology) in 1991, MTCA is now in its 33rd year regulating cleanup of contaminated sites in our state.

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The site of the future Maddux North building being readied for redevelopment in 2020. The property formerly housed a dry cleaner, which left contamination in the surrounding soils. Cleanup of the site followed regulations per MTCA.

Dave and Ali Furmall, LHG, Brownfield Program Lead at Ecology, will present “Community Investment: Overview of Affordable Housing Cleanup Grant Program and Other Brownfield Program Resources.” Their talk will give an overview of Ecology’s Affordable Housing Cleanup Grant Program, which helps organizations purchase and remediate sites across Washington to build affordable housing.

Since the program’s start in 2016, Dave and Aspect have actively collaborated with Ecology, real estate developers, legal teams, and nonprofit housing groups to get projects funded and properties ready for cleanup. Our work now spans Bellingham, Ellensburg, and several sites in Seattle, including the launch pilot-project Mt. Baker Housing Association’s Maddux development. The project built two buildings with 203 total units on the site of a former dry cleaner and gas station/auto repair shop.

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Maddux North, funded in part by the Affordable Housing Cleanup Grant program, welcomed residents in March 2023.

The day-long seminar hosted by Law Seminars International will spotlight other aspects of MTCA, including an overview of the recent updates—the first major updates in over 20 years—covering new decision-making criteria and other requirements that will impact future cleanup projects.

For the full seminar agenda and information how to register, visit the Law Seminars International website.

Boiling Groundwater and Steaming Soil: A Unique Cleanup for a Distinctive Site

The Spic’n Span property in Seattle’s International District has a unique story -- serving as the neighborhood’s only dry cleaning business for over 50 years, until it closed in 2019. It also has a unique story through the lens of a brownfield project. To clean up the chlorinated solvents and mineral spirits left in soil and groundwater from a half century of dry cleaning operations, the project team applied an innovative type of in situ thermal treatment, electrical resistance heating (ERH). ERH heats the shallow soil to an average temperature of 212 degrees Fahrenheit (100 Celsius), until the groundwater starts to literally boil, which then allows the vaporized contaminants to be captured and removed.

A Tailored Cleanup in a Historic Neighborhood

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The Spic‘n Span building is in Seattle’s Chinatown-International District and care needed to be taken to follow the neighborhood’s preservation goals during site remediation.
Photo Credit: grego1402, as licensed under Creative Commons

The Spic‘n Span building sits in Seattle’s International Special Review District (ISRD), which is one of Seattle's eight historic districts. The ISRD is a collection of early 20th-century commercial and hotel buildings in the center of this historically Asian American community. It also has the Seattle Chinatown National Register Historic District within it, which helps spotlight the important contributions of the Chinatown/International District area on a national level.

From a pure remedial design perspective, knocking the former dry cleaner building down and excavating the contaminated soil and groundwater directly beneath it likely would have been chosen as the solution at a similar site. But because of the ISRD’s preservation goals, there are established processes for reviewing changes to any existing building within the district. Keeping the existing building as-is during treatment allowed for a smoother approval process with the ISRD.

Not only does ERH treatment result in less ground disturbance compared to a remedial excavation, but contamination is permanently removed and destroyed in the subsurface without requiring excavation and off-site disposal at a landfill. It can target a very specific treatment depth interval, without the need to remove overlying uncontaminated fill or deal with excavation shoring or dewatering. ERH treatment can also potentially reach areas where excavation isn’t possible, such as underneath the sidewalk. The advantages of ERH for this specific site made it a clear winner for the project team.

What is Electrical Resistance Heating?

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ERH runs electrical current through arrays in shallow soil, the current heats the soil, which in turn heats groundwater to a boiling point where it vaporizes. The vapors are captured and treated and then safely discharged.
Photo Credit: TRS Group, Inc

ERH is a relatively new remediation technology that can be the right fit for certain cleanup sites. It involves passing an electrical current through moisture in the soil between an array of electrodes. As the current flows through the moisture in soil pores, the resistance of the soil produces heat.

The heat strips the volatile contaminants out of the soil and vaporizes groundwater and non-aqueous phase liquid (NAPL), if present. steam and contaminant vapors produced by the heat are captured by subsurface vapor extraction systems, conveyed to the surface, and then treated for permitted discharge. ERH is a highly effective remediation solution for contaminated soil, as it is able to reduce contaminated soil and groundwater concentrations up to 99 percent. It has been successfully implemented at over 300 sites worldwide.

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Fall 2021 temperature reading of soil cores, still at 130 F, from the active ERH operation phase of the project cleanup.
Photo Credit: Aspect Consulting

The Spic‘n Span site was a good fit for this type of treatment, as ERH would eliminate the majority of contamination without having to disturb the building. However, care had to be taken to confirm that the subsurface was the right makeup for ERH. For instance, the soil type dictates the soil resistivity, which determines how readily the soil will conduct electricity—a low resistivity will require large amounts of electrical current, and a high resistivity will require high voltages. The fill and historical marine deposits (sandy silt, stiff silt and medium dense silty and gravelly sands) at Spic‘n Span fell in the sweet spot of optimal ERH performance.

Another consideration for ERH application is high concentrations of organic carbon in soil, which can cause chemicals to stick to the soil and not evaporate easily and ERH is less effective for heavy petroleum compounds. Lastly, ERH demands careful logistical planning and constant and methodical monitoring to confirm that the heat generated doesn’t affect underground utilities (especially plastic ones) or change the soil properties resulting in damage to the structural integrity of the building. All of these considerations were closely evaluated before and during the ERH implementation at the Spic’n Span site.

Plugging In 52 Electrodes to Power Cleanup

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Over 50 electrodes and 40 vapor recovery wells were installed across the 0.3-acre site.
Photo Credits: Aspect Consulting

Aspect led the remediation evaluation and technology selection, working closely with the City’s ISRD team to confirm that proper care would be taken during the cleanup selection. Aspect partnered with the TRS Group, who are ERH specialists, to design and build the system at the property. Bench scale testing was conducted to confirm the effectiveness of ERH for site soils and contaminants, and provide the basis for the full-scale design.

The Site was divided into four areas based on depth of contamination and 52 electrodes – 15 feet apart – were installed into the shallow subsurface. Over 40 vapor recovery wells along with a vapor recovery system were installed to capture and convey the permitted discharge. A temporary transformer and power poles were installed by Seattle City Light to power the ERH system. Once the system was in place, the team was ready to flip the switch.

Treatment Goals Achieved

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At system shutdown in early 2022, the average temperature in shallow soil was 97 degrees Celsius in the focused treatment area.
Figure Credit: Aspect Consulting

The ERH system powered up in August 2021. Over about 6 months of operation, the cleanup action removed approximately 800 pounds of air phase petroleum hydrocarbons and 42 pounds of perchloroethylene. Once confirmation soil samples were below cleanup levels, the system was shut down and the post-treatment “cool-down” period was initiated. Fast forward to 2023 and, following 12 months of post-treatment monitoring, contaminant concentrations detected on the property are below cleanup levels.

ERH is a remediation solution that is suited for very specific brownfield situations. In this case, the restrictions of having to leave the building intact and treat contamination in place led to the selection of this innovative cleanup solution. Unique site challenges require unique solutions, which is what makes our job so exciting as environmental consultants.

Contact Principal Engineer Jeremy Porter or Project Engineer Delia Massey for more information.

Data Teams as Gatekeepers to Unlock Brownfield Cleanups

Environmental data teams methodically confirm cleanup levels and visualize the 'cleanup finish line' with the regulatory criteria and client end goals

What is the measure of ‘clean’ at brownfield sites? Before any digging of contaminated dirt or treatment of contaminated groundwater, there is much upfront work by regulators and project teams – chemists, data analysts, geologists, engineers, and more – to determine the appropriate cleanup levels to use for a given site. The cleanup levels are the north star that every brownfield cleanup team steers by.

To Succeed, Be Sure What ‘Clean’ Looks Like

Aspect’s environmental data team regularly keeps the finger on the pulse of regulatory databases and uses tools – such as the open-source programming language R – to streamline brownfield cleanup projects.

Using R to automate screening level updates allows project teams to:

• Make changes quickly and confidently

• Minimize the risk of errors and omissions

• Provide much-improved process transparency

• Streamline communications across the project team

Keeping up on the best available science gives project managers greater assurance that their sites are being appropriately measured against regulatory criteria, providing a smoother path forward in the management and remediation of contaminated sites.

A Peek into Regulatory Data World with CLARC

CLARC is the Washington State Department of Ecology’s (Ecology) Cleanup Levels and Risk Calculation spreadsheet that is the basis for calculating cleanup levels under Ecology’s Model Toxics Control Act (MTCA). MTCA is Washington state’s cleanup rule which governs over 13,000+ known or suspected contaminated sites. CLARC is a key measure of what defines success at these cleanup projects and a living document that is maintained and updated by Ecology, as needed, with major updates every six months to align with changes to state and federal regulatory (e.g., US Environmental Protection Agency (EPA)) criteria.

Aspect engineer evaluating a vapor intrusion system at Art Brass Plating – a South Seattle cleanup site. The measure of success for these systems — and projects — rely on knowing the correct and up-to-date cleanup level criteria

The data tables in CLARC provide the various input parameters used to calculate screening levels for a huge array of chemicals in soil, groundwater, surface water, soil gas, and air—as well as the resulting calculated cleanup level values themselves. The calculated values are routinely used by remediation project managers to screen analytical results (from samples collected in the field) against federal, state, or other regulatory thresholds.

What is R and How Does it Accurately Automate Away Manual Data Entry?

R is an open-source software environment used for statistical computing and graphics. Recently, Aspect’s data team wrote a package of R code to use CLARC’s input parameters to calculate a suite of specific screening levels. The same code can be run any time the input values in CLARC are updated, generating quality assurance tables to alert Aspect’s data team of potential issues, and providing summary tables for Aspect project managers to review cleanup level changes and consider their potential impact to their various environmental sites.

Various input parameters, including regulatory requirements, chemistry, site use, human safety and environmental quality are entered into our custom R tool to make and maintain a reliable, reproducible metric set for project success

Since there are usually screening levels for hundreds of different analytes at remediation cleanups  – e.g., petroleum and diesel, arsenic, tetrachloroethylene and more – when the CLARC database is updated by the regulator, it can be difficult to see if there have been any changes and which analytes may have been affected.

Aspect uses the industry standard EQuiS environmental data management system. The R tool helps us better use EQuIS to manage and screen environmental data against cleanup levels. Before using R, preparing CLARC-based screening and cleanup levels for upload to EQuIS required tedious data wrangling in Excel and institutional knowledge of what analytes should be compared to which screening levels. With R, the process involves little more than a click of a button

Data Problem Solving that Makes Remediation Easier

R simplifying the complexity of the brownfield cleanup level process

Brownfield remediation cleanups require imagining a range of scenarios for the future use of a ‘clean’ property. Will the site be used for residential, commercial, or industrial purposes? What pollutants are present and where? It all starts with the cleanup level criteria.

Overall, this work by Aspect’s data team – who are meticulous at knowing the state-of-the-science regulatory criteria – ensures Aspect’s project teams have the correct screening or cleanup levels based on the most current toxicity guidance, which helps avoid rework later on in the process and saves time and money for the client.

$23 Million for Affordable Housing Funding in Seattle

Lots of happy faces, hugs, and cheers at a recent June press conference as Amazon’s Housing Equity Fund director, Catherine Buell, announced the $23 Million award to Gardner Global for their Central District project; Mt. Baker Housing Association for their Grand Street Commons project; Mt. Baker Housing Village projects; and to El Centro de la Raza for their El Centro Columbia City project.

Over several years, Aspect has partnered with Mt. Baker Housing, Lake Union Partners, and Gardner Global on revitalizing several key brownfield cleanup sites in south Seattle for Affordable Housing goals.

Learn more about Aspect’s affordable housing work here: Affordable Housing — Aspect Consulting

This week, Aspect staff attended an event featuring Jaebadiah Gardner with Gardner Global, David Tan with Mt. Baker Housing Association, Estela Ortega with El Centro de la Raza, as well as Seattle Mayor Bruce Harrell.

Groundbreaking Ground Improvements for Seattle Affordable Housing

Construction at Mt. Baker Housing Association’s Maddux Development is underway—the beginning of the end of a project that is bringing 203 units of affordable housing to Seattle’s Mt. Baker neighborhood. It features an innovative partnership between MBHA and Ecology as the first project under Ecology’s Healthy Housing program to help fund the environmental cleanup of future affordable housing sites. It also features a first-in-Seattle use of a ground improvement technique called displacement rigid inclusions to address the site’s challenging geology and the project’s limited budget.

Drilling the displacement rigid inclusions columns.

Soil Liquefaction Muddies Building Design

The land under the new Maddux buildings consists of very loose fill soils that lie on top of glacial recessional deposits – a hodgepodge of loose soils left behind as the last glaciers retreated from the Puget Sound area thousands of years ago. Under that are stiffer soils that were consolidated by the weight of the glacier. The loose soils are saturated by groundwater that lies on top of it unable to infiltrate into the harder soil underneath.

During an earthquake, the saturated, loosely packed grains of soils at the Maddux site could be shaken to a point where the elevated water pressure within the pore spaces increases the space between grains and causes the soil to lose strength and flow like a liquid in a process called liquefaction.

Think of wiggling your toes in the sand while standing on a beach near where the waves come in—the Maddux site soils would respond in similar fashion. When the shaking starts, the loose soils would become even weaker and any foundation bearing weight on them would settle, crack, and potentially collapse. Structures on sites like Maddux require particular design for seismic conditions in order to be built safely.

Weak Soils Get an Automatic F

The building code divides the soils at sites into six classes – ranging from A (strong rock)  to F (weak, loose, liquefiable soils) – based on the characteristics of the upper 100 feet of soil from the base of any future building. These site classes set the parameters for how a building must be designed to respond to strong shaking from earthquakes.

The building code rates sites with any amount of soils at risk of liquefaction as Site Class F. Building on Site Class F sites usually requires either deep foundations or ground improvement—both of which are more expensive than conventional shallow foundations. The building itself can also be more expensive, since building on weaker soils often requires more steel and other materials. And for an affordable housing project like this one, cost is a critical factor to the viability of the project.

Conscious of these cost concerns, Aspect’s geotechnical team started to investigate the most effective foundation design for building on a Site Class F site such as Maddux. In a nutshell: It’s complicated.

Design vs. Complex Site Geology vs. Costs

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This figure shows the varying elevations of bearing layer –soils that can safely bear the weight of a building foundation – at the Maddux site.

The land the Maddux site is on has been through a lot. The last glacier left not just weak soils but left them at wildly varying depths. You can drill at one spot and reach stiffer soils within a few feet of the surface, then move over 10 feet, drill again, and have the strong glacial soils be 15 or more feet further down.

Add to this the legacy contamination from former dry cleaners and a gas station that has since spread throughout the soil and groundwater. Excavation to remove contaminated soil was already part of the site’s environmental plan, but to extend that excavation to remove all the soft and liquefiable soils in addition to all the contaminated soils would have required more digging, deeper shoring, and more off-site soil disposal – and a lot more money. We also needed to make sure whatever ground improvement we used didn’t interfere with our environmental team’s remediation plan.

Whatever the method, we wanted it to be as cost-effective as possible. Ecology’s funding for the Maddux development only covers the environmental remediation. Any expense for building foundations is the responsibility of MBHA, which as a nonprofit has limited funding. Our geotechnical team carefully weighed the costs versus benefits of several options. For example, conventional deep auger cast piles, which are often used at sites like Maddux, are relatively inexpensive to install, but they require a lot of concrete and steel to construct, adding more to the cost of materials. They also don’t improve the ground around the piles; the class rating would still be an F, which increases the cost of the building itself.

Displacement Rigid Inclusions to Raise the Grade

As we weighed the factors, it became apparent that displacement rigid inclusions were the most appropriate and cost-effective technique for the site. Rigid inclusions are a ground improvement method that use columns of concrete to transfer the weight of a structure through loose soils down to more competent bearing soils below, thereby reducing potential damage from liquefaction.

What made the ground improvement for the Maddux project unique in the Seattle area was the use of displacement rigid inclusions. Displacement rigid inclusions are a type of rigid inclusion that involve specialty tooling that densifies the soil around each column. The act of drilling the columns “displaces” the ground around it. The soil between the columns is pushed together and becomes denser, thereby reducing the chance it will liquefy during an earthquake. Displacement rigid inclusions provide structural support for the building with the same element that is used to mitigate liquification.

Tests to Pass the SDCI Test

There aren’t many chances to test seismic design—the Seattle area hasn’t experienced a “design-level” earthquake, one with the magnitude we are designing our buildings for, in hundreds of years, so it can be hard to predict exactly how a building will respond. Instead, engineers study what has happened during other earthquakes under similar circumstances. We can then apply that understanding to safely develop innovative techniques to protect against earthquakes at more problematic sites like Maddux. To use displacement rigid inclusions for the Maddux project, the design required approval from the City of Seattle. Displacement rigid inclusions had never been used before to change the site class of a project in Seattle.

During design, we conducted cone penetrometer tests (CPTs) to determine the soils’ geotechnical engineering properties plus extensive laboratory tests on the soils. We worked with specialty ground improvement contractor Condon Johnson to assess whether the soils would respond to the displacement the way we thought they could. From those tests, the detailed ground improvement design was established including the spacing of each column needed to effectively strengthen the soil between columns.

Our team met regularly with Seattle Department of Construction and Inspections (SDCI) to present our design approach. Conservative estimates were developed for how much densification would be possible in the site soils. We found that the ground improvement could be designed to achieve adequate densification to eliminate liquefaction risk –and thus raise the site class.

SDCI approved the approach during design, but all was contingent on the results of verification testing after the rigid inclusions were installed. If we installed the columns and performed more CPTs that showed enough improvement in the soil strength, they would give final approval.

Installing the Columns

We started installing the displacement rigid inclusion columns at the Maddux site at the beginning of 2021. The drilling required specialty displacement auger tooling, and because this technique isn’t used much in this area, the driller had to bring the displacement auger up from California.

Displacement rigid inclusion installation in early 2021 at the Maddux site

A cage of rebar is set in place after the column is filled with concrete.

The displacement auger drilled 18-inch-diameter columns down through the weaker soils and into the underlying dense glacially overridden soil layer. As the auger pulled out, it pumped concrete into the void created by the auger pushing soil to the side. The concrete itself is under pressure, which pushed out the soil even more, which aides in densification. Once the auger was fully removed, a “cage” of rebar could then be lowered in to reinforce the concrete once it cures.

In all, there were 249 columns drilled at Maddux North and 219 at Maddux South, each placed about 5 feet apart center to center, installed over two months.

The Results

Once the displacement rigid inclusions were installed, we completed another round of CPTs to physically verify that we achieved the level of densification we predicted in design. Results from the post-treatment CPTs showed the displacement rigid inclusions had worked even better than we thought. Our team delivered the data to the City that showed the soils at Maddux were no longer liquifiable.

Aspect, as the geotechnical engineer of record, then gave the recommendation that the site class could change. This opinion was backed by the robust quality controls we used during construction, documentation of the verification CPTs, and post-treatment liquefaction analyses showing the liquefaction risk had been removed.

The Site Class at Maddux was raised from an ‘F’ to a ‘D’. A ‘D’ rating allowed for the structures to be designed using less materials, therefore saving money on construction costs.

The Maddux project represents a successful use of an innovative ground improvement technique on a complicated site in conjunction with an extensive environmental cleanup. See the Maddux ‘Story Map’ for more context on the project.

What if You Can’t Dig Your Way Out of a Brownfield Cleanup?

Brownfield site cleanups are difficult for construction teams, redevelopment plans, and the community. It’s even harder when you can’t dig and haul the contaminated soil and there’s impacts to groundwater. Aspect’s Adam Griffin and Doug Hillman discuss successful strategies for complicated cleanup sites in this Daily Journal of Commerce article.

Inspecting the Vapor Intrusion Mitigation System at Art Brass Plating in Seattle

Seattle Commits $110 Million to Create Almost 2,000 Affordable Homes

The City of Seattle will make the largest award in the City’s history to invest $110 Million for 1,944 new affordable homes. This announcement continues the recent affordable housing funding the City has made over the last several years.

This is great news for the region as well as the group of sponsoring organizations that are leading the projects. Organizations like Mt. Baker Housing Association (MBHA) and the Seattle Chinatown International District Preservation and Development Authority (SCIDpda) are instrumental in developing and promoting access to housing for the community. To help them reach their development goals to create more local housing options, Aspect is currently providing environmental cleanup, regulatory negotiation, and public outreach support to MBHA and SCIDpda on several affordable housing projects in Seattle.

The ongoing Maddux development provides 150+ affordable housing units close to transit in the Mt. Baker neighborhood. The City of Seattle’s recent investment news will help create close to 2,000 affordable homes like this across the region.

Our work with MBHA includes three projects in the Mt. Baker and Rainier Beach neighborhoods. We’re also helping SCIDpda, along with Lake Union Partners and Capitol Hill Housing, on the 3-block Goodwill site in the International District.

Learn more about Aspect’s work to help our partners transform and restore urban sites into affordable housing communities here: http://www.aspectconsulting.com/affordablehousing

Innovative Affordable Housing Solutions Continue in South Seattle

The Seattle City Council recently approved the 2nd Redevelopment Opportunity Zone (ROZ) in Seattle’s history for the 700-unit Grand Street Commons housing development near the future Judkins Park light-rail station. The ROZ designation means that this innovative $20 Million private/non-profit partnership (Lake Union Partners and Mt. Baker Housing, respectively) now has direct access to state funds to build a 700-unit development—with about half of those units earmarked for affordable housing. These 350 future units, together with the 160 units planned at The Maddux (the City’s first ROZ zone near the Mt. Baker light-rail station), brings 500+ ROZ-designated affordable housing units coming online in the next five years in South Seattle.

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The 700-unit Grand Street Commons is a unique private/public partnership, where approximately half the units will be affordable housing. The cleanup for this brownfield site is being led by Aspect and funded by a new approach to access money specifically for affordable housing projects.

Aspect, with law firm Perkins Coie, has helped Mt. Baker Housing pioneer this ROZ model to unlock state-backed grant funding in a first-of-its-kind model. Recognizing this success, the state introduced the Healthy Housing Program this fall– earmarked specifically for affordable housing developers looking at restoring land at brownfield sites.

Learn more about new approaches to restore land and find solutions for our affordable housing crisis here: www.aspectconsulting.com/affordablehousing.

Washington State Helps Turn Brownfields into Affordable Housing

See Washington State Department of Ecology’s new article covering the state’s new Healthy Housing Remediation Program for restoring contaminated land to promote affordable housing. Mt. Baker Housing’s 160-unit project in South Seattle — which Aspect is leading the cleanup for — was the inspiration for this program.

Read more here.

Learn more here: https://www.aspectconsulting.com/affordablehousing