Major Milestone at Complex Pasco Landfill Cleanup to Remove 35,000 Drums of Waste

The Pasco Landfill Site reached a recent milestone from the State Department of Ecology. Ecology announced plans to remove over 35,000 drums from an industrial waste cell and haul away the worst contaminants for disposal. While the landfill received municipal solid waste from 1958 to 1993, industrial waste was received only during the early 1970s. Since 1992, over 32 entities have investigated and grappled with how to cleanup the Site. In 2014, cleanup planning for the latent industrial waste took a turn with the development of a subsurface fire and product observed at the water table. Aspect's landfill engineering team has been working on cleanup design engineering and strategies at this Site for over 12 years.

See Ecology's video to learn more about this project as well as the current public comment period, now open through October 3.

Air Quality Rule Change Means Lower Hurdle for Washington State Landfill Owners

The Washington State Department of Ecology is revising the air quality thresholds for toxic air pollutants (TAPs; WAC 173-460), based on best available science. These proposed changes have some significant effects for landfill owners looking to keep air quality good, protective of human health and the environment, and doing so cost effectively. The key proposed changes are:

The last flare this landfill in Port Angeles will ever need. When the gas is no longer combustible, reliable treatment will be provided by biofilter technology – made easier by recent updates in air quality criteria.

  • Two of the most conservative constituents commonly found in landfill gas, benzene and vinyl chloride, will have higher thresholds (by factors of 3.7 and 8.9, respectively).

  • The threshold for hydrogen sulfide – a common driver for odor control in landfill gas – did not change. However, biofilter technology is showing promise as an economic and reliable method for polishing treatment.

  • The threshold for trichloroethene went down by a factor of 0.4. This constituent has also been commonly found in landfill gas, and the new threshold may or may not change our clients’ treatment obligations.

What this means for landfill owners is that air quality compliance should be easier to demonstrate. This means:

  • Downscaling treatment at older landfills can focus on odor control instead of destruction efficiency for volatile organic compounds (VOCs) as TAPs.

  • The costs associated with flaring landfill gas can be re-directed to biofilter technology for polishing treatment for odor control.

  • The schedule for ending or minimizing post-closure obligations associated with landfill gas treatment can be accelerated.

Next Steps

This rule-making process is on-going, and details of the process are provided at Ecology’s website: https://ecology.wa.gov/460rulemaking.

A hearing on the re-calculated air quality thresholds is planned for July 16, 2019, and comments are due be July 23, 2019.

Barring delays, the new rule on air quality thresholds becomes effective in late October 2019.

For more information on what the implication of these changes for landfill owners and managers, contact Associate Engineer Peter Bannister at (206) 780-7728 and pbannister@aspectconsulting.com.

Inspiring Burgeoning Environmental Consultants

For an interdisciplinary WWU course led by Dr. Ruth Sofield and focused on the Science and Management of Contaminated Sites (SMoCS), Aspect’s Steve Germiat and Kirsi Longley gave budding environmental consultants a look at what life and work is really like for professional environmental consultants.

To complement the students’ landfill RI/FS case study, Kirsi presented Aspect’s recent RI/FS work at a landfill in western Washington. The presentation focused on the scope of the investigation, the findings, including how volatile contaminants can transfer between landfill gas and groundwater, and how the findings were developed into recommendations for remedial alternatives.  In addition to the scientific and technological challenges of environmental remediation, Steve and Kirsi addressed the nuts and bolts of a consultant’s role in the MTCA cleanup process, and the skills and attributes that enable a consultant to excel. Looking back on the presentation, Dr. Sofield said “Students benefit so much from interactions with Steve and Kirsi.  To actually learn from a practitioner and see that classroom material has real application changes how students think about and participate in their education.  It changes a lot for the students, including their intended career path.”

About SMoCS

In collaboration with Washington State Department of Ecology Toxics Cleanup Program, WWU’s Huxley College of the Environment (Huxley) offers undergraduate students a course series in the Science and Management of Contaminated sites (SMoCS). The SMoCS series includes three courses that build knowledge of the contaminated site cleanup process in Washington State with an emphasis on how scientific investigations are conducted, use of the technical documents associated with cleanups, the roles of different parties in cleanup decisions, and enhanced professional skills.  For more information on the program visit http://faculty.wwu.edu/harperr3/SMoCS.shtml.

30 Years and Beyond: Caring for Landfills Post Closure

For landfill owners and operators, an ounce of prevention can be worth hundreds of thousands of dollars of cure. Read Chris Augistine’s DJC article about navigating the regulatory requirements and applying strategies to reduce monitoring requirements, save money, and successfully plan for post-closure care at closed landfills.

READ IT HERE

How Dirty is the Dirt: Ripple Effects of Proposed Solid Waste Handling Regulations

The difference between “clean” and “dirty” dirt may become a lot more complex if new solid waste handling regulations take effect in Washington state. The state’s Department of Ecology (Ecology) has proposed significant revisions to Washington Administrative Code (WAC) Chapter 173-350, which governs how solid waste is managed. The proposed changes, which will be formally proposed later this year, will affect a number of solid waste practices, but the key revisions with the most significant implications concern creation of a new section establishing and standardizing criteria for managing the movement, reuse and disposal of soil and sediment  that is considered “clean” under the state’s Model Toxics Control Act (MTCA) but may have trace levels of contaminants (draft WAC 173-350-995).

Excavated soil from Seattle City Light’s new Denny Substation in South Lake Union. Under proposed new solid waste regulations, managing, hauling, and receiving this soil will likely be much more complicated for engineers, redevelopment teams, and landfill operators.

With the Puget Sound region by some counts leading the nation in development projects – which all generate dirt during construction excavation that must be reused or hauled away – establishing soil management protocols will likely have significant ripple effects in the business and regulated community. Consider just one urban skyrise, as this article on construction dirt does. A typical downtown Seattle building project could potentially generate 250,000 cubic yards of soil (equal to 25,000 dump truck loads) that must be removed from the site. The new soil and sediment criteria would potentially mean higher sampling costs, more complex soil management plans, additional reuse constraints, and greater soil volumes filling up limited landfill space.

How managing “Dirty” Dirt would change

Contaminated sites are regulated under MTCA, which provides screening criteria for defining impacted soil. Soil with contaminants below MTCA screening levels is considered “clean”. Currently, the end use of “clean” excavated soil is largely determined by criteria set by individual receiving facilities—gravel mine, landfill, reuse site, etc. These facilities may all have different standards for what level of impacted soil they will accept. The new proposed regulation would change that, formulating the screening process for “clean” soil and creating formal soil reuse and disposal acceptance criteria. This means that “clean” soil (albeit with low levels of contaminants at concentrations protective of human health and the environment) would now need to go through rigorous sampling, laboratory analysis, evaluation, and jurisdictional health department permitting just to be hauled away. This would be a big change from the current process, where this same “clean” soil can be reused as fill because it is deemed “protective” of human health and the environment, per MTCA.

Implications of new regulations

At the heart of the update is the intent to formally regulate soils that are not perfectly clean. Ecology hopes the rule update will streamline management, decrease delays in soil movement, reduce the potential for creating new cleanup sites, and reduce environmental damage. Practitioners see the implications of these proposed rule updates as increasing the cost of development projects, slowing development schedules, creating a regulatory quagmire, and causing landfills to fill with soil that could be put to use elsewhere.  

Too Much Flare, Not Enough Gas

Aspect’s Peter Bannister, along with King County’s Dan Swope, will co-present at the 2016 Solid Waste Association of North America (SWANA) Northwest Regional Symposium in Vancouver, BC on Friday April 8th.

As landfills age and landfill gas generation inevitably declines, landfill operators face the problem of using legacy collection and control systems that weren’t designed to harvest dwindling amounts of landfill gas. Simply continuing operation of these oversized systems is often not practical or financially prudent.

Peter and Dan will present the Enumclaw Landfill case-study and focus on how landfill gas forensics has proven to be an innovative solution to coaxing better performance out of existing landfill gas collection and control systems, and designing downscaled systems, at closed landfills in King County, Washington State.

Peter and Dan will present Friday morning at 10:30AM in technical session 6B – Advances in Landfill Gas Management.  Learn more about the conference HERE and view the agenda HERE.

We look forward to seeing you there!