Article as posted on: http://www.thonline.com/article.cfm?id=305015
2-TABLESPOON MERCURY SPILL COULD BE COSTLY — MAYBE EVEN $1.5 MILLION
Looking for the proverbial needle in a haystack, the city hunts for the toxin that dripped across two(2) 200-foot diameter tank filled with 9 feet of rock.
The total cost and who will bear the burden for a mercury spill cleanup at Dubuque’s Water Pollution Control Plant has yet to be determined, but it could reach $1.5 million.
The cleaning process continues at the plant. The spill occurred Sept. 23 when workers deconstructing a long-dormant filtering system released the mercury while removing machinery. The Iowa Occupational Safety and Health Administration issued three citations and fined the city $1,925.
“The feeling between the city and the contractor is to move forward and keep the project on schedule,” plant manager Jonathan Brown said. “Then we’ll go back to the contract documents and decide who is responsible for what.”
Project engineer Steve Sampson-Brown said all city contracts contain a dispute-resolution provision, and the city will seek reimbursement for the cleanup. Part of the cost is part of the original bid because the city planned to remove 30,000 tons of rock from the filtering tanks and transport it to the landfill for use in road construction.
Brown said the EPA has measurements for what it considers clean stone, and 90 percent of the stone from the plant is clean and has gone to the landfill. The remaining 10 percent will be pulled apart and tested in smaller groups.
“They test the air for the presence of mercury vapor and it will be tested in smaller and smaller amounts,” Brown said.
About 2 tablespoons of mercury dripped across a 200-foot diameter tank filled with 9 feet of rock.
Brown compared the spill to slowly shaking a teaspoon of salt over a bushel basket of pebbles.
“It’s not quite the needle in the haystack analogy, but it is very close,” he said. “It is a very involved process. Initially, regulators considered the whole tank contaminated, and it took a considerable amount of negotiation to reduce the amount of contaminated stone.”
Brown said the mercury was used as a sealant in trickling filters manufactured in the 1950s and 1960s.
“Through the years, those things have been redesigned, but there is still mercury in old trickling filters across the country,” Brown said.
Brown said the filter tanks are being converted into water-storage units as part of the plant’s conversion to anaerobic digestion. The tanks hold about 3 million gallons each and that capacity holds excess water for treatment during heavy rains when the stormwater system infiltrates the sanitary sewer system. The city has been cited for releasing untreated wastewater during those rain events.
“We will be able to eliminate about 90 to 95 percent of our recent effluent violations by using these tanks,” Brown said. “At the time, it seemed like a good idea.”
* The city is contesting one of the three citations. It reads: “Prior to permitting employees to start demolition operations, when the presence of any hazardous substances was apparent or suspected, testing and purging was not performed and the hazard eliminated before demolition was started. This violation carries a proposed penalty of $1,375.
“We feel in the contract between the city and the contractor there is a written plan in place for each part or the process,” Brown said. “We did have a plan in place and it was a matter of the contractor’s workers moving the trickling filters out of sequence.”
* The second citation reads: “The written emergency plan was not kept at the workplace and made available for employee review.”
There is no proposed penalty for this violation.
“We didn’t have an emergency plan for mercury,” Brown said. “We haven’t used that equipment for 30 years and, quite frankly, I didn’t think of it. I don’t know how I can be any more brutal to myself than that.”
* The third citation reads: “The employer’s hazard communication program did not include methods the employer will use to inform the other employer(s) of any precautionary measures that need to be taken to protect employees during the workplace’s normal operating conditions and in foreseeable emergencies.” This violation carries a proposed penalty of $550.
“In the contract documents there are several references to asbestos, chlorine and mercury, so from a practical standpoint we were doing it, but it was not written down in the overarching documents,” Brown said. “The underground storage removal is all spelled out in the contract.”
– end of article –
Notes from Keith Hitzke, President of NSEC:
Mercury Spill Clean-up at the Pollution Control Plant, Dubuque Iowa 1/4/2011 fromKeith Hitzke on Vimeo.
The Elemental Mercury spill was much larger than initially reported of two tablespoons. On September 23, 2010, Clean Harbors provided emergency response mercury spill clean-up services at the Pollution Control wastewater plant in Dubuque Iowa. After several days of spill clean-up by Clean Harbors, NSEC was contracted by Miron Construction to take control of the spill and develop a work plan for review and approval by the Iowa DNR and EPA Region 7 to complete the mercury spill response clean-up. The spill’s involve two(2), 200’ diameter concrete trickling filter tanks with estimated 15,000 tons of 2”-6” fractured stone per tank. The amount of elemental mercury spilled is undetermined but much greater than initially reported (2 tablespoons) to the Iowa Department of Natural Resources. The spill occurred during the removal of two large mercury filled bearings from the center columns of the trickling filters by a local contractor. The elemental mercury was also spilled outside the tanks.
NSEC is currently working to recover the elemental mercury with a chemical process designed and constructed by NSEC. The project is expected to be completed in March of 2011. It is currently undetermined as to the actual amount of elemental was spill during the bearing dismantlement. Keith Hitzke, principal response manager for NSEC is providing the lead on-site management for the duration of the project.
