Hanford Landfill Being Expanded, Modernized in Wa.

Thu May 01, 2008 - West Edition
CEG




RICHLAND, Wash. (AP) Change is under way at Hanford’s central landfill — the spot where vast amounts of low-level radioactive wastes have been disposed of in the last dozen years.

The landfill — officially the Environmental Restoration Disposal Facility — is being expanded and modernized with equipment that wasn’t available when it opened in 1996 on the nuclear reservation in southeast Washington.

The modernization is due at least in part to problems discovered early last year. A former worker fabricated results of compaction testing at the landfill, and an unrelated malfunction in a water collection system in the lining beneath the landfill went undetected for months.

In mid-April, two new machines with cleated rollers began compacting waste to make sure sinkholes don’t develop after a cap is eventually placed over the landfill. The compactors are equipped with global positioning systems to keep track of how many times each part of the landfill has been compacted as more waste is added.

The new system will replace the former requirement for manual compaction testing.

“No longer will people have to suit up and go into the contaminated area,” said Owen Robertson, the project engineer for the Department of Energy.

Meanwhile, a new computerized system will monitor the leachate collection system in the landfill’s clay lining. Data will be transmitted by radio frequency to the computer, which will automatically telephone managers if it detects a problem.

The landfill was designed to have 10 disposal “cells.” A subcontractor, DelHur Industries, is working on the construction of cells seven and eight. Workers have dug up 600,000 cu. yd. (458,700 cu m) of soil and will dig up a total of 1.3 million cu. yd. (900,000 cu m) to finish the two cells early next year.

The cells will be 70 ft. (21 m) deep and measure a combined 500 by 1,000 ft. (152 by 304 m) at their base — big enough to hold about 2.8 million tons (2.5 million t) of material.

The two cells will be the first to include a monitoring system for water beneath the landfill’s clay base. The system will check for moisture that could indicate contamination is seeping from the landfill long before it is detected in nearby monitoring wells.

Washington Closure Hanford, which operates the landfill, is preparing to start accepting more waste from around the Hanford site, including contaminated soil from along the reservation’s river corridor.

It has added a scale and is adding six new trucks. Drivers bring in about 150 truckloads of debris a day, and that could increase to as many as 250 truckloads.