Grant County Ephrata Landfill 1

Ecology and the two parties responsible for cleanup, Grant County and the City of Ephrata, have negotiated an agreed order for cleanup work at the Grant County Ephrata Landfill 1. The order includes an interim remedial action plan outlining cleanup that will be completed before the remedial investigation/feasibility study to guide final cleanup.

The City of Ephrata began operating the Ephrata Landfill around 1942 and owned and managed it until 1974. Grant County has managed the landfill since 1974. The landfill was an open dump before 1962. Waste was put into an unlined cell until a new, lined cell with leak containment opened in 2005, which still accepts waste.

About 2,000 drums of industrial waste were buried in August 1975. The Environmental Protection Agency added the landfill to the list of potential hazardous sites in 1979. Ecology completed a Phase I site investigation in 1987, and groundwater sampling began in 1988. In 1990, contaminants, including metals, solvents, and other chemicals, were found in groundwater.

Since 2007, the site has had ongoing investigation into the extent of contamination, and the parties responsible have completed a number of interim cleanup actions.

2008: Drum removal

All 2,353 drums of industrial waste were removed from the north end of the landfill. Forty-six drums were empty, and 1,038 drums were partially empty. Most drums contained liquid, but some had solid material. Leaking was noted in 209 drums as they were pulled from the ground. Moderate-to-heavy damage was noted on 1,579 drums. Samples from the drums went to a lab for analyses before disposal. Most of the drums were placed in overpacks before shipment to an incinerator in Aragonite, Utah. Contaminated soil and spilled drum contents that were hazardous waste were sent to a disposal facility. Photos of the drum removal are available on Ecology's Flickr account.

Contaminated water pooled in the bottom of the excavation. Volatile organic compounds in the water included methylene chloride, acetone, 1,1-dichloroethane, 2-butanone, MIBK, toluene, ethyl-benzene, and xylenes. Contractors made sumps to drain the liquid. Over 6,000 gallons of water were removed. The contaminated water was stored in a tank on-site and then transported to a disposal facility.

2009: Landfill capping

A protective cap was completed over the old cell, including the area where the drums of industrial waste used to be buried. This cap keeps rain and snow melt from infiltrating contaminated soil.

2012: Soil removed from north end

Contaminated soil from the Neva Lake Road extension was removed in November and December 2012. After, the consultants for the parties responsible for cleanup decided more work was needed to complete the feasibility study, so the deadline was changed to June 30, 2017.

2017: Pilot system installed to remove soil contamination

The multi-phase extraction (MPE) pilot test started on May 23, 2017, and continued for 4.5 months. The purpose of the test was to evaluate its ability to treat contaminants in groundwater and soil. Work included installing several new extraction and observation wells, piping, contaminated vapor and liquid treatment systems, and an evaporation pond.

A total of 87,000 gallons of groundwater were extracted, treated, and disposed. A total of 7,100,000 cubic feet of vapor were extracted, treated, and vented. The pilot test showed that a full MPE system should have 6-inch wells spaced no more than 40 feet apart, should be operated at a low vacuum, and additional liquid treatment steps should be considered.

2018: More soil removed from north end and investigation work continues

In February 2018, 25 test pits were sampled in the area where contaminated soil was removed in 2012. The sampling found an area of arsenic-contaminated soil. The area was excavated to bedrock, and approximately 1,210 cubic yards of contaminated soil were removed.

In late 2018, one of the parties responsible for cleanup hired new technical consultants. After reviewing the cleanup work at the landfill, they decided the complex hydrogeology of the area needed more characterization before the feasibility study is completed. Eighty-one new wells began being drilled in September 2019. After information from the wells is reviewed, they will decide whether more is needed or if the feasibility study can be completed.

When the draft remedial investigation and feasibility study are complete, they will be available for public review and comment. The remedial investigation documents the extent and locations of contamination, and the feasibility study presents options for final cleanup.