[NEWS] Chlorine, Mercury Emissions Under Scrutiny at Oregon Trash Incinerator
– by Tracy Loew, March 12, 2016, Statesman Journal
State environmental regulators are cracking down on the amount of chlorine and mercury Marion County’s waste-to-energy burner discharges to the Willamette River.
Covanta Marion, a subsidiary of New Jersey-based Covanta Energy Corp., operates the garbage incinerator for the county. It burns about 550 tons of municipal waste per day at the facility in Brooks.
Covanta uses well water for flushing built-up minerals from the boiler and cooling tower. That water – about 88,000 gallons per day – then is treated and discharged to a 12-inch pipe that runs six miles into the Willamette River at milepost 71.7, near the Wheatland Ferry.
Covanta’s federal permit to discharge wastewater to the river expired on Nov. 30, 2009. It has been allowed to continue operating under its previous permit because it filed a timely application with the state Department of Environmental Quality, which has been delegated authority over the permits.
DEQ now has proposed a new permit for the facility that addresses both chlorine and mercury.
According to the draft permit, Covanta uses chlorine as a biocide to control algae buildup in its cooling towers.
The new permit proposes lower limits on the average concentration of chlorine in the wastewater the company discharges.
DEQ plans to give Covanta until Nov. 30, 2016, to determine whether the new limits can be met simply by taking samples at the point the wastewater enters the river, rather than where it leaves the plant.
The thought is that much of that chlorine naturally evaporates during the water’s journey to the river.
If that doesn’t work, Covanta must submit plans for a dechlorination system within one year of the permit approval.
The new permit also gives Covanta two years to submit a plan to monitor and reduce the amount of mercury it releases to the river.
There is no mercury limit in the current permit. According to the proposed permit, the company uses sulfuric acid to adjust the water’s pH. That sulfuric acid contains trace amounts of mercury.
At DEQ’s request, in January 2015 Covanta sampled water at the river outfall and detected a mercury concentration of 1.5 nanograms per liter.
The company also tested at source water wells, and within the facility.
“The facility’s one-time mercury sampling event showed that there are mercury sources entering the waste stream that do not originate from the intake water,” DEQ wrote in the proposed permit.
The Willamette River exceeds water quality standards for mercury at the company’s outfall.
Covanta has proposed diverting about a quarter of the treated wastewater for use as irrigation water for grass, trees, shrubs and rose bushes on its 17-acre site.
That should help reduce the amount of mercury discharged into the river, said Darby Randklev, Covanta Marion manager.
The public is invited to comment on the proposal. Comments must be received by 5 p.m. March 26. They can be faxed to 503-378-7944; emailed to Everett.email@example.com; or mailed to Carrie Everett, permit coordinator, 4026 Fairview Industrial Drive, Salem, OR 97302-1142.
DEQ will hold a public hearing on the proposal if it receives written requests from at least 10 people or from an organization representing at least 10 people.
The facility has been in operation since 1986.