Riverbend fined $13K for leachate spills
According to spokeswoman Jackie Lang, the company has not decided whether to file an appeal. It has 20 days to do so.
Leachate is the leftover liquid that migrates to the bottom of the landfill and is then collected in ponds or in storage tanks, depending on its toxicity. It contains volatile organic compounds, including acetone, 2-butanone and 2-hexanone, along with heavy metals, including arsenic, barium and chromium.
The seepages, characterized as minor in reports filed with DEQ, contaminated soil and a nearby creek.
The January spill occurred when work on a stormwater diversion swale clogged a French drain. Soil testing conducted in response revealed “residual contaminant concentrations below safe levels.”
No traces of volatile organic compounds were detected. Traces of potentially toxic metals were found, but reflected levels typically occurring naturally in the Willamette Valley.
The larger February spill occurred during a snowstorm, when weather prevented material stored in tanks from being pumped into trucks for transportation to a treatment facility.
Workers discovered the leakage on the snowy morning of Feb. 10, some 12.5 hours after an earlier check showed nothing amiss. There is no way to tell whether it continued for only a few minutes or stretched over several hours.
The leachate, consisting primarily of liquid collected in the landfill’s gas extraction wells, reached a creek roughly 300 feet from the landfill.
To keep the extraction wells working properly, the leachate that collects is routinely pumped into three 21,000 gallon storage tanks near the north side of the landfill. It is kept separate from the rest of the landfill leachate, which is pumped to an on-site pond, because it poses a greater odor threat.
Testing of the creek downstream, undertaken twice at three separate locations, showed contamination “below safe levels for both humans and animals, even based on long-term exposure,” according to the engineering firm CH2M-Hill.
Fifteen soil samples taken from 12 locations showed traces of mercury, cyanide, nitrite, and volatile and semi-volatile organic compounds, such as dichloromethane, napthalene, acetone, phenol and 2-hexanone. The report said levels of nearly all samples were below the amounts deemed potentially harmful to plants, animals and people.
“Our staff identified the problem and took immediate action to address it,” Lang said. “We self-reported the incidents to the DEQ and we are now in full compliance. We have also made a number of structural and operational changes to ensure this doesn’t happen again.”
Lang said Riverbend had installed additional berms, alarms and diversion pipes. Also, she said, it plans to install a fourth leachate storage tank by May 30, serving to significantly increase the landfill’s leachate holding capacity.