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.

Testing Innovative Methods for Landfill Gas Monitoring in King County

Scientists from the CSE Corporation (a company developing cutting-edge gas detection devices used in air-quality monitoring) and Aspect remediation engineers are working in partnership to develop new methods for continuous methane-gas monitoring at landfills. CSE’s methane-gas monitoring products use solar-powered instruments outfitted with telemetry. Solar power eliminates the need for frequent battery replacement while telemetry allows remote monitoring of the data. With cooperation from King County Solid Waste Division, CSE has provided Aspect with test units to install at several of the County’s closed landfills to gauge the effectiveness of this technology for the landfill industry.

CSE has roots in the mining industry and a history of innovations, including the first self-contained rescue-breathing apparatus for use by mine personnel. KCSWD, Aspect, and CSE are testing the devices ability to monitor methane, a primary source of greenhouse gas emissions from landfills.
 

Got methane? CSE remote methane monitoring setup with telemetry and solar panel  on a passive landfill gas collection system in King County, Washington.

Got methane? CSE remote methane monitoring setup with telemetry and solar panel  on a passive landfill gas collection system in King County, Washington.

You can get there from here: Ending post-closure activities at old landfills

After landfills stop accepting waste, they transition into a post-closure period of typically 30 years or more. Towards the end of the post-closure period, landfill managers try to terminate or modify monitoring requirements in compliance with criteria and regulations.  Data collected on settlement, leachate generation, groundwater quality and landfill gas production are evaluated to demonstrate if monitoring activities can be terminated or reduced.

In one example of successful post-closure transition, see Seattle’s South Park Landfill before (2007) and after (2016) closure. The landfill was capped and redeveloped as a parking and storage facility.

On April 26 at the 2017 NW Regional SWANA (Solid Waste Association of North America) Conference in Tulalip, Aspect’s Peter Bannister will discuss his experience at closed landfills in eastern and western Washington and lessons learned that have set these sites up for terminating or reducing post-closure activities with regulatory certainty.

Learn more and register here.

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!